python: urls return [None] if not pypi

.github/workflows/build-containers.yml

@@ -113,7 +113,7 @@ jobs:
           password: ${{ secrets.DOCKERHUB_TOKEN }}
 
       - name: Build & Deploy ${{ matrix.dockerfile[0] }}
-        uses: docker/build-push-action@5cd11c3a4ced054e52742c5fd54dca954e0edd85
+        uses: docker/build-push-action@16ebe778df0e7752d2cfcbd924afdbbd89c1a755
         with:
           context: dockerfiles/${{ matrix.dockerfile[0] }}
           platforms: ${{ matrix.dockerfile[1] }}

.github/workflows/unit_tests.yaml

@@ -16,27 +16,38 @@ jobs:
       matrix:
         os: [ubuntu-latest]
         python-version: ['3.7', '3.8', '3.9', '3.10', '3.11', '3.12']
+        concretizer: ['clingo']
         on_develop:
         - ${{ github.ref == 'refs/heads/develop' }}
         include:
+        - python-version: '3.11'
+          os: ubuntu-latest
+          concretizer: original
+          on_develop: ${{ github.ref == 'refs/heads/develop' }}
         - python-version: '3.6'
           os: ubuntu-20.04
+          concretizer: clingo
           on_develop: ${{ github.ref == 'refs/heads/develop' }}
         exclude:
         - python-version: '3.7'
           os: ubuntu-latest
+          concretizer: 'clingo'
           on_develop: false
         - python-version: '3.8'
           os: ubuntu-latest
+          concretizer: 'clingo'
           on_develop: false
         - python-version: '3.9'
           os: ubuntu-latest
+          concretizer: 'clingo'
           on_develop: false
         - python-version: '3.10'
           os: ubuntu-latest
+          concretizer: 'clingo'
           on_develop: false
         - python-version: '3.11'
           os: ubuntu-latest
+          concretizer: 'clingo'
           on_develop: false
 
     steps:
@@ -74,6 +85,7 @@ jobs:
     - name: Run unit tests
       env:
           SPACK_PYTHON: python
+          SPACK_TEST_SOLVER: ${{ matrix.concretizer }}
           SPACK_TEST_PARALLEL: 2
           COVERAGE: true
           UNIT_TEST_COVERAGE: ${{ matrix.python-version == '3.11' }}
@@ -170,6 +182,7 @@ jobs:
     - name: Run unit tests (full suite with coverage)
       env:
           COVERAGE: true
+          SPACK_TEST_SOLVER: clingo
       run: |
           share/spack/qa/run-unit-tests
     - uses: codecov/codecov-action@e28ff129e5465c2c0dcc6f003fc735cb6ae0c673
@@ -200,6 +213,7 @@ jobs:
         brew install dash fish gcc gnupg2 kcov
     - name: Run unit tests
       env:
+        SPACK_TEST_SOLVER: clingo
         SPACK_TEST_PARALLEL: 4
       run: |
         git --version

etc/spack/defaults/config.yaml

@@ -170,6 +170,23 @@ config:
   # If set to true, Spack will use ccache to cache C compiles.
   ccache: false
 
+
+  # The concretization algorithm to use in Spack. Options are:
+  #
+  #   'clingo': Uses a logic solver under the hood to solve DAGs with full
+  #       backtracking and optimization for user preferences. Spack will
+  #       try to bootstrap the logic solver, if not already available.
+  #
+  #   'original': Spack's original greedy, fixed-point concretizer. This
+  #       algorithm can make decisions too early and will not backtrack
+  #       sufficiently for many specs. This will soon be deprecated in
+  #       favor of clingo.
+  #
+  # See `concretizer.yaml` for more settings you can fine-tune when
+  # using clingo.
+  concretizer: clingo
+
+
   # How long to wait to lock the Spack installation database. This lock is used
   # when Spack needs to manage its own package metadata and all operations are
   # expected to complete within the default time limit. The timeout should

etc/spack/defaults/packages.yaml

@@ -20,14 +20,12 @@ packages:
       awk: [gawk]
       armci: [armcimpi]
       blas: [openblas, amdblis]
-      c: [gcc]
       cxx: [gcc]
       D: [ldc]
       daal: [intel-oneapi-daal]
       elf: [elfutils]
       fftw-api: [fftw, amdfftw]
       flame: [libflame, amdlibflame]
-      fortran: [gcc]
       fortran-rt: [gcc-runtime, intel-oneapi-runtime]
       fuse: [libfuse]
       gl: [glx, osmesa]

etc/spack/defaults/windows/config.yaml

@@ -1,5 +1,6 @@
 config:
   locks: false
+  concretizer: clingo
   build_stage::
     - '$spack/.staging'
   stage_name: '{name}-{version}-{hash:7}'

lib/spack/docs/conf.py

@@ -206,7 +206,6 @@ def setup(sphinx):
     ("py:class", "six.moves.urllib.parse.ParseResult"),
     ("py:class", "TextIO"),
     ("py:class", "hashlib._Hash"),
-    ("py:class", "concurrent.futures._base.Executor"),
     # Spack classes that are private and we don't want to expose
     ("py:class", "spack.provider_index._IndexBase"),
     ("py:class", "spack.repo._PrependFileLoader"),

lib/spack/docs/packaging_guide.rst

@@ -1263,11 +1263,6 @@ Git fetching supports the following parameters to ``version``:
   option ``--depth 1`` will be used if the version of git and the specified
   transport protocol support it, and ``--single-branch`` will be used if the
   version of git supports it.
-* ``git_sparse_paths``: Use ``sparse-checkout`` to only clone these relative paths.
-  This feature requires ``git`` to be version ``2.25.0`` or later but is useful for
-  large repositories that have separate portions that can be built independently.
-  If paths provided are directories then all the subdirectories and associated files
-  will also be cloned. 
 
 Only one of ``tag``, ``branch``, or ``commit`` can be used at a time.
 
@@ -1366,41 +1361,6 @@ Submodules
   For more information about git submodules see the manpage of git: ``man
   git-submodule``.
 
-Sparse-Checkout
-  You can supply ``git_sparse_paths`` at the package or version level to utilize git's 
-  sparse-checkout feature. This will only clone the paths that are specified in the 
-  ``git_sparse_paths`` attribute for the package along with the files in the top level directory.
-  This feature allows you to only clone what you need from a large repository.
-  Note that this is a newer feature in git and requries git ``2.25.0`` or greater.
-  If ``git_sparse_paths`` is supplied and the git version is too old
-  then a warning will be issued and that package will use the standard cloning operations instead.
-  ``git_sparse_paths`` should be supplied as a list of paths, a callable function for versions,
-  or a more complex package attribute using the ``@property`` decorator. The return value should be
-  a list for a callable implementation of ``git_sparse_paths``.
-
-  .. code-block:: python
-
-    def sparse_path_function(package)
-        """a callable function that can be used in side a version"""
-        # paths can be directories or functions, all subdirectories and files are included
-        paths = ["doe", "rae", "me/file.cpp"]
-        if package.spec.version >  Version("1.2.0"):
-            paths.extend(["fae"])
-        return paths
-
-    class MyPackage(package):
-        # can also be a package attribute that will be used if not specified in versions
-        git_sparse_paths = ["doe", "rae"]
-
-        # use the package attribute
-        version("1.0.0")
-        version("1.1.0")
-        # use the function
-        version("1.1.5", git_sparse_paths=sparse_path_func)
-        version("1.2.0", git_sparse_paths=sparse_path_func)
-        version("1.2.5", git_sparse_paths=sparse_path_func)
-        version("1.1.5", git_sparse_paths=sparse_path_func)
-
 .. _github-fetch:
 
 ^^^^^^

lib/spack/external/__init__.py

@@ -18,7 +18,7 @@
 
 * Homepage: https://pypi.python.org/pypi/archspec
 * Usage: Labeling, comparison and detection of microarchitectures
-* Version: 0.2.5-dev (commit 7e6740012b897ae4a950f0bba7e9726b767e921f)
+* Version: 0.2.4 (commit 48b92512b9ce203ded0ebd1ac41b42593e931f7c)
 
 astunparse
 ----------------

lib/spack/external/_vendoring/distro/distro.py

@@ -1265,29 +1265,27 @@ def _distro_release_info(self) -> Dict[str, str]:
             match = _DISTRO_RELEASE_BASENAME_PATTERN.match(basename)
         else:
             try:
-                with os.scandir(self.etc_dir) as it:
-                    etc_files = [
-                        p.path for p in it
-                        if p.is_file() and p.name not in _DISTRO_RELEASE_IGNORE_BASENAMES
-                    ]
+                basenames = [
+                    basename
+                    for basename in os.listdir(self.etc_dir)
+                    if basename not in _DISTRO_RELEASE_IGNORE_BASENAMES
+                    and os.path.isfile(os.path.join(self.etc_dir, basename))
+                ]
                 # We sort for repeatability in cases where there are multiple
                 # distro specific files; e.g. CentOS, Oracle, Enterprise all
                 # containing `redhat-release` on top of their own.
-                etc_files.sort()
+                basenames.sort()
             except OSError:
                 # This may occur when /etc is not readable but we can't be
                 # sure about the *-release files. Check common entries of
                 # /etc for information. If they turn out to not be there the
                 # error is handled in `_parse_distro_release_file()`.
-                etc_files = [
-                    os.path.join(self.etc_dir, basename)
-                    for basename in _DISTRO_RELEASE_BASENAMES
-                ]
-
-            for filepath in etc_files:
-                match = _DISTRO_RELEASE_BASENAME_PATTERN.match(os.path.basename(filepath))
+                basenames = _DISTRO_RELEASE_BASENAMES
+            for basename in basenames:
+                match = _DISTRO_RELEASE_BASENAME_PATTERN.match(basename)
                 if match is None:
                     continue
+                filepath = os.path.join(self.etc_dir, basename)
                 distro_info = self._parse_distro_release_file(filepath)
                 # The name is always present if the pattern matches.
                 if "name" not in distro_info:

lib/spack/external/_vendoring/jsonschema/_format.py

@@ -231,6 +231,96 @@ def is_host_name(instance):
     return True
 
 
+try:
+    # The built-in `idna` codec only implements RFC 3890, so we go elsewhere.
+    import idna
+except ImportError:
+    pass
+else:
+    @_checks_drafts(draft7="idn-hostname", raises=idna.IDNAError)
+    def is_idn_host_name(instance):
+        if not isinstance(instance, str_types):
+            return True
+        idna.encode(instance)
+        return True
+
+
+try:
+    import rfc3987
+except ImportError:
+    try:
+        from rfc3986_validator import validate_rfc3986
+    except ImportError:
+        pass
+    else:
+        @_checks_drafts(name="uri")
+        def is_uri(instance):
+            if not isinstance(instance, str_types):
+                return True
+            return validate_rfc3986(instance, rule="URI")
+
+        @_checks_drafts(
+            draft6="uri-reference",
+            draft7="uri-reference",
+            raises=ValueError,
+        )
+        def is_uri_reference(instance):
+            if not isinstance(instance, str_types):
+                return True
+            return validate_rfc3986(instance, rule="URI_reference")
+
+else:
+    @_checks_drafts(draft7="iri", raises=ValueError)
+    def is_iri(instance):
+        if not isinstance(instance, str_types):
+            return True
+        return rfc3987.parse(instance, rule="IRI")
+
+    @_checks_drafts(draft7="iri-reference", raises=ValueError)
+    def is_iri_reference(instance):
+        if not isinstance(instance, str_types):
+            return True
+        return rfc3987.parse(instance, rule="IRI_reference")
+
+    @_checks_drafts(name="uri", raises=ValueError)
+    def is_uri(instance):
+        if not isinstance(instance, str_types):
+            return True
+        return rfc3987.parse(instance, rule="URI")
+
+    @_checks_drafts(
+        draft6="uri-reference",
+        draft7="uri-reference",
+        raises=ValueError,
+    )
+    def is_uri_reference(instance):
+        if not isinstance(instance, str_types):
+            return True
+        return rfc3987.parse(instance, rule="URI_reference")
+
+
+try:
+    from strict_rfc3339 import validate_rfc3339
+except ImportError:
+    try:
+        from rfc3339_validator import validate_rfc3339
+    except ImportError:
+        validate_rfc3339 = None
+
+if validate_rfc3339:
+    @_checks_drafts(name="date-time")
+    def is_datetime(instance):
+        if not isinstance(instance, str_types):
+            return True
+        return validate_rfc3339(instance)
+
+    @_checks_drafts(draft7="time")
+    def is_time(instance):
+        if not isinstance(instance, str_types):
+            return True
+        return is_datetime("1970-01-01T" + instance)
+
+
 @_checks_drafts(name="regex", raises=re.error)
 def is_regex(instance):
     if not isinstance(instance, str_types):
@@ -250,3 +340,86 @@ def is_draft3_time(instance):
     if not isinstance(instance, str_types):
         return True
     return datetime.datetime.strptime(instance, "%H:%M:%S")
+
+
+try:
+    import webcolors
+except ImportError:
+    pass
+else:
+    def is_css_color_code(instance):
+        return webcolors.normalize_hex(instance)
+
+    @_checks_drafts(draft3="color", raises=(ValueError, TypeError))
+    def is_css21_color(instance):
+        if (
+            not isinstance(instance, str_types) or
+            instance.lower() in webcolors.css21_names_to_hex
+        ):
+            return True
+        return is_css_color_code(instance)
+
+    def is_css3_color(instance):
+        if instance.lower() in webcolors.css3_names_to_hex:
+            return True
+        return is_css_color_code(instance)
+
+
+try:
+    import jsonpointer
+except ImportError:
+    pass
+else:
+    @_checks_drafts(
+        draft6="json-pointer",
+        draft7="json-pointer",
+        raises=jsonpointer.JsonPointerException,
+    )
+    def is_json_pointer(instance):
+        if not isinstance(instance, str_types):
+            return True
+        return jsonpointer.JsonPointer(instance)
+
+    # TODO: I don't want to maintain this, so it
+    #       needs to go either into jsonpointer (pending
+    #       https://github.com/stefankoegl/python-json-pointer/issues/34) or
+    #       into a new external library.
+    @_checks_drafts(
+        draft7="relative-json-pointer",
+        raises=jsonpointer.JsonPointerException,
+    )
+    def is_relative_json_pointer(instance):
+        # Definition taken from:
+        # https://tools.ietf.org/html/draft-handrews-relative-json-pointer-01#section-3
+        if not isinstance(instance, str_types):
+            return True
+        non_negative_integer, rest = [], ""
+        for i, character in enumerate(instance):
+            if character.isdigit():
+                non_negative_integer.append(character)
+                continue
+
+            if not non_negative_integer:
+                return False
+
+            rest = instance[i:]
+            break
+        return (rest == "#") or jsonpointer.JsonPointer(rest)
+
+
+try:
+    import uritemplate.exceptions
+except ImportError:
+    pass
+else:
+    @_checks_drafts(
+        draft6="uri-template",
+        draft7="uri-template",
+        raises=uritemplate.exceptions.InvalidTemplate,
+    )
+    def is_uri_template(
+        instance,
+        template_validator=uritemplate.Validator().force_balanced_braces(),
+    ):
+        template = uritemplate.URITemplate(instance)
+        return template_validator.validate(template)

lib/spack/external/archspec/cpu/detect.py

@@ -47,11 +47,7 @@ def decorator(factory):
 
 
 def partial_uarch(
-    name: str = "",
-    vendor: str = "",
-    features: Optional[Set[str]] = None,
-    generation: int = 0,
-    cpu_part: str = "",
+    name: str = "", vendor: str = "", features: Optional[Set[str]] = None, generation: int = 0
 ) -> Microarchitecture:
     """Construct a partial microarchitecture, from information gathered during system scan."""
     return Microarchitecture(
@@ -61,7 +57,6 @@ def partial_uarch(
         features=features or set(),
         compilers={},
         generation=generation,
-        cpu_part=cpu_part,
     )
 
 
@@ -95,7 +90,6 @@ def proc_cpuinfo() -> Microarchitecture:
         return partial_uarch(
             vendor=_canonicalize_aarch64_vendor(data),
             features=_feature_set(data, key="Features"),
-            cpu_part=data.get("CPU part", ""),
         )
 
     if architecture in (PPC64LE, PPC64):
@@ -351,10 +345,6 @@ def sorting_fn(item):
     generic_candidates = [c for c in candidates if c.vendor == "generic"]
     best_generic = max(generic_candidates, key=sorting_fn)
 
-    # Relevant for AArch64. Filter on "cpu_part" if we have any match
-    if info.cpu_part != "" and any(c for c in candidates if info.cpu_part == c.cpu_part):
-        candidates = [c for c in candidates if info.cpu_part == c.cpu_part]
-
     # Filter the candidates to be descendant of the best generic candidate.
     # This is to avoid that the lack of a niche feature that can be disabled
     # from e.g. BIOS prevents detection of a reasonably performant architecture

lib/spack/external/archspec/cpu/microarchitecture.py

@@ -2,7 +2,9 @@
 # Archspec Project Developers. See the top-level COPYRIGHT file for details.
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
-"""Types and functions to manage information on CPU microarchitectures."""
+"""Types and functions to manage information
+on CPU microarchitectures.
+"""
 import functools
 import platform
 import re
@@ -63,24 +65,21 @@ class Microarchitecture:
                 passed in as argument above.
             * versions: versions that support this micro-architecture.
 
-        generation (int): generation of the micro-architecture, if relevant.
-        cpu_part (str): cpu part of the architecture, if relevant.
+        generation (int): generation of the micro-architecture, if
+            relevant.
     """
 
-    # pylint: disable=too-many-arguments,too-many-instance-attributes
+    # pylint: disable=too-many-arguments
     #: Aliases for micro-architecture's features
     feature_aliases = FEATURE_ALIASES
 
-    def __init__(self, name, parents, vendor, features, compilers, generation=0, cpu_part=""):
+    def __init__(self, name, parents, vendor, features, compilers, generation=0):
         self.name = name
         self.parents = parents
         self.vendor = vendor
         self.features = features
         self.compilers = compilers
-        # Only relevant for PowerPC
         self.generation = generation
-        # Only relevant for AArch64
-        self.cpu_part = cpu_part
         # Cache the ancestor computation
         self._ancestors = None
 
@@ -112,7 +111,6 @@ def __eq__(self, other):
             and self.parents == other.parents  # avoid ancestors here
             and self.compilers == other.compilers
             and self.generation == other.generation
-            and self.cpu_part == other.cpu_part
         )
 
     @coerce_target_names
@@ -145,8 +143,7 @@ def __repr__(self):
         cls_name = self.__class__.__name__
         fmt = (
             cls_name + "({0.name!r}, {0.parents!r}, {0.vendor!r}, "
-            "{0.features!r}, {0.compilers!r}, generation={0.generation!r}, "
-            "cpu_part={0.cpu_part!r})"
+            "{0.features!r}, {0.compilers!r}, {0.generation!r})"
         )
         return fmt.format(self)
 
@@ -193,7 +190,6 @@ def to_dict(self):
             "generation": self.generation,
             "parents": [str(x) for x in self.parents],
             "compilers": self.compilers,
-            "cpupart": self.cpu_part,
         }
 
     @staticmethod
@@ -206,7 +202,6 @@ def from_dict(data) -> "Microarchitecture":
             features=set(data["features"]),
             compilers=data.get("compilers", {}),
             generation=data.get("generation", 0),
-            cpu_part=data.get("cpupart", ""),
         )
 
     def optimization_flags(self, compiler, version):
@@ -365,11 +360,8 @@ def fill_target_from_dict(name, data, targets):
         features = set(values["features"])
         compilers = values.get("compilers", {})
         generation = values.get("generation", 0)
-        cpu_part = values.get("cpupart", "")
 
-        targets[name] = Microarchitecture(
-            name, parents, vendor, features, compilers, generation=generation, cpu_part=cpu_part
-        )
+        targets[name] = Microarchitecture(name, parents, vendor, features, compilers, generation)
 
     known_targets = {}
     data = archspec.cpu.schema.TARGETS_JSON["microarchitectures"]

lib/spack/external/archspec/json/cpu/microarchitectures.json

@@ -2225,14 +2225,10 @@
         ],
         "nvhpc": [
           {
-            "versions": "21.11:23.8",
+            "versions": "21.11:",
 	    "name": "zen3",
             "flags": "-tp {name}",
-	    "warnings": "zen4 is not fully supported by nvhpc versions < 23.9, falling back to zen3"
-          },
-          {
-            "versions": "23.9:",
-            "flags": "-tp {name}"
+	    "warnings": "zen4 is not fully supported by nvhpc yet, falling back to zen3"
           }
 	]
       }
@@ -2715,8 +2711,7 @@
             "flags": "-mcpu=thunderx2t99"
           }
         ]
-      },
-      "cpupart": "0x0af"
+      }
     },
     "a64fx": {
       "from": ["armv8.2a"],
@@ -2784,8 +2779,7 @@
             "flags": "-march=armv8.2-a+crc+crypto+fp16+sve"
           }
         ]
-      },
-      "cpupart": "0x001"
+      }
     },
     "cortex_a72": {
       "from": ["aarch64"],
@@ -2822,8 +2816,7 @@
                   "flags" : "-mcpu=cortex-a72"
               }
           ]
-      },
-      "cpupart": "0xd08"
+      }
     },
     "neoverse_n1": {
       "from": ["cortex_a72", "armv8.2a"],
@@ -2909,8 +2902,7 @@
                   "flags": "-tp {name}"
               }
           ]
-      },
-      "cpupart": "0xd0c"
+      }
     },
     "neoverse_v1": {
       "from": ["neoverse_n1", "armv8.4a"],
@@ -2934,6 +2926,8 @@
           "lrcpc",
           "dcpop",
           "sha3",
+          "sm3",
+          "sm4",
           "asimddp",
           "sha512",
           "sve",
@@ -3034,8 +3028,7 @@
                   "flags": "-tp {name}"
               }
           ]
-      },
-      "cpupart": "0xd40"
+      }
     },
     "neoverse_v2": {
       "from": ["neoverse_n1", "armv9.0a"],
@@ -3059,10 +3052,13 @@
 	  "lrcpc",
 	  "dcpop",
 	  "sha3",
+	  "sm3",
+	  "sm4",
 	  "asimddp",
 	  "sha512",
 	  "sve",
 	  "asimdfhm",
+	  "dit",
 	  "uscat",
 	  "ilrcpc",
 	  "flagm",
@@ -3070,12 +3066,18 @@
 	  "sb",
 	  "dcpodp",
 	  "sve2",
+	  "sveaes",
+	  "svepmull",
+	  "svebitperm",
+	  "svesha3",
+	  "svesm4",
 	  "flagm2",
 	  "frint",
 	  "svei8mm",
 	  "svebf16",
 	  "i8mm",
-	  "bf16"
+	  "bf16",
+	  "dgh"
       ],
       "compilers" : {
           "gcc": [
@@ -3100,19 +3102,15 @@
                   "flags" : "-march=armv8.5-a+sve -mtune=cortex-a76"
               },
               {
-                  "versions": "10.0:11.3.99",
+                  "versions": "10.0:11.99",
                   "flags" : "-march=armv8.5-a+sve+sve2+i8mm+bf16 -mtune=cortex-a77"
               },
-	      {
-                  "versions": "11.4:11.99",
-                  "flags" : "-mcpu=neoverse-v2"
-              },
               {
-                  "versions": "12.0:12.2.99",
+                  "versions": "12.0:12.99",
                   "flags" : "-march=armv9-a+i8mm+bf16 -mtune=cortex-a710"
               },
 	      {
-                  "versions": "12.3:",
+                  "versions": "13.0:",
                   "flags" : "-mcpu=neoverse-v2"
               }
           ],
@@ -3147,113 +3145,7 @@
                   "flags": "-tp {name}"
               }
           ]
-      },
-      "cpupart": "0xd4f"
-    },
-    "neoverse_n2": {
-      "from": ["neoverse_n1", "armv9.0a"],
-      "vendor": "ARM",
-      "features": [
-          "fp",
-	  "asimd",
-	  "evtstrm",
-	  "aes",
-	  "pmull",
-	  "sha1",
-	  "sha2",
-	  "crc32",
-	  "atomics",
-	  "fphp",
-	  "asimdhp",
-	  "cpuid",
-	  "asimdrdm",
-	  "jscvt",
-	  "fcma",
-	  "lrcpc",
-	  "dcpop",
-	  "sha3",
-	  "asimddp",
-	  "sha512",
-	  "sve",
-	  "asimdfhm",
-	  "uscat",
-	  "ilrcpc",
-	  "flagm",
-	  "ssbs",
-	  "sb",
-	  "dcpodp",
-	  "sve2",
-	  "flagm2",
-	  "frint",
-	  "svei8mm",
-	  "svebf16",
-	  "i8mm",
-	  "bf16"
-      ],
-      "compilers" : {
-          "gcc": [
-              {
-                  "versions": "4.8:5.99",
-                  "flags": "-march=armv8-a"
-              },
-              {
-                  "versions": "6:6.99",
-                  "flags" : "-march=armv8.1-a"
-              },
-              {
-                  "versions": "7.0:7.99",
-                  "flags" : "-march=armv8.2-a -mtune=cortex-a72"
-              },
-              {
-                  "versions": "8.0:8.99",
-                  "flags" : "-march=armv8.4-a+sve -mtune=cortex-a72"
-              },
-              {
-                  "versions": "9.0:9.99",
-                  "flags" : "-march=armv8.5-a+sve -mtune=cortex-a76"
-              },
-              {
-                  "versions": "10.0:10.99",
-                  "flags" : "-march=armv8.5-a+sve+sve2+i8mm+bf16 -mtune=cortex-a77"
-              },
-              {
-                  "versions": "11.0:",
-                  "flags" : "-mcpu=neoverse-n2"
-              }
-          ],
-          "clang" : [
-              {
-                  "versions": "9.0:10.99",
-                  "flags" : "-march=armv8.5-a+sve"
-              },
-              {
-                  "versions": "11.0:13.99",
-                  "flags" : "-march=armv8.5-a+sve+sve2+i8mm+bf16"
-              },
-              {
-                  "versions": "14.0:15.99",
-                  "flags" : "-march=armv9-a+i8mm+bf16"
-              },
-              {
-                  "versions": "16.0:",
-                  "flags" : "-mcpu=neoverse-n2"
-              }
-          ],
-          "arm" : [
-              {
-                  "versions": "23.04.0:",
-                  "flags" : "-mcpu=neoverse-n2"
-              }
-          ],
-          "nvhpc" : [
-              {
-                  "versions": "23.3:",
-                  "name": "neoverse-n1",
-                  "flags": "-tp {name}"
-              }
-          ]
-      },
-      "cpupart": "0xd49"
+      }
     },
     "m1": {
       "from": ["armv8.4a"],
@@ -3319,8 +3211,7 @@
             "flags" : "-mcpu=apple-m1"
           }
         ]
-      },
-      "cpupart": "0x022"
+      }
     },
     "m2": {
       "from": ["m1", "armv8.5a"],
@@ -3398,8 +3289,7 @@
             "flags" : "-mcpu=apple-m2"
           }
         ]
-      },
-      "cpupart": "0x032"
+      }
     },
     "arm": {
       "from": [],

lib/spack/external/archspec/json/cpu/microarchitectures_schema.json

@@ -52,9 +52,6 @@
                   }
                 }
               }
-            },
-            "cpupart": {
-              "type": "string"
             }
           },
           "required": [
@@ -110,4 +107,4 @@
       "additionalProperties": false
     }
   }
-}
+}

lib/spack/external/patches/distro.patch

@@ -1,45 +0,0 @@
-diff --git a/lib/spack/external/_vendoring/distro/distro.py b/lib/spack/external/_vendoring/distro/distro.py
-index 89e1868047..50c3b18d4d 100644
---- a/lib/spack/external/_vendoring/distro/distro.py
-+++ b/lib/spack/external/_vendoring/distro/distro.py
-@@ -1265,27 +1265,29 @@ def _distro_release_info(self) -> Dict[str, str]:
-             match = _DISTRO_RELEASE_BASENAME_PATTERN.match(basename)
-         else:
-             try:
--                basenames = [
--                    basename
--                    for basename in os.listdir(self.etc_dir)
--                    if basename not in _DISTRO_RELEASE_IGNORE_BASENAMES
--                    and os.path.isfile(os.path.join(self.etc_dir, basename))
--                ]
-+                with os.scandir(self.etc_dir) as it:
-+                    etc_files = [
-+                        p.path for p in it
-+                        if p.is_file() and p.name not in _DISTRO_RELEASE_IGNORE_BASENAMES
-+                    ]
-                 # We sort for repeatability in cases where there are multiple
-                 # distro specific files; e.g. CentOS, Oracle, Enterprise all
-                 # containing `redhat-release` on top of their own.
--                basenames.sort()
-+                etc_files.sort()
-             except OSError:
-                 # This may occur when /etc is not readable but we can't be
-                 # sure about the *-release files. Check common entries of
-                 # /etc for information. If they turn out to not be there the
-                 # error is handled in `_parse_distro_release_file()`.
--                basenames = _DISTRO_RELEASE_BASENAMES
--            for basename in basenames:
--                match = _DISTRO_RELEASE_BASENAME_PATTERN.match(basename)
-+                etc_files = [
-+                    os.path.join(self.etc_dir, basename)
-+                    for basename in _DISTRO_RELEASE_BASENAMES
-+                ]
-+
-+            for filepath in etc_files:
-+                match = _DISTRO_RELEASE_BASENAME_PATTERN.match(os.path.basename(filepath))
-                 if match is None:
-                     continue
--                filepath = os.path.join(self.etc_dir, basename)
-                 distro_info = self._parse_distro_release_file(filepath)
-                 # The name is always present if the pattern matches.
-                 if "name" not in distro_info:

lib/spack/external/patches/jsonschema.patch

@@ -13,191 +13,3 @@ index 6b630cdfbb..1791fe7fbf 100644
 -__version__ = metadata.version("jsonschema")
 +
 +__version__ = "3.2.0"
-diff --git a/lib/spack/external/_vendoring/jsonschema/_format.py b/lib/spack/external/_vendoring/jsonschema/_format.py
-index 281a7cfcff..29061e3661 100644
---- a/lib/spack/external/_vendoring/jsonschema/_format.py
-+++ b/lib/spack/external/_vendoring/jsonschema/_format.py
-@@ -231,96 +231,6 @@ def is_host_name(instance):
-     return True
- 
- 
--try:
--    # The built-in `idna` codec only implements RFC 3890, so we go elsewhere.
--    import idna
--except ImportError:
--    pass
--else:
--    @_checks_drafts(draft7="idn-hostname", raises=idna.IDNAError)
--    def is_idn_host_name(instance):
--        if not isinstance(instance, str_types):
--            return True
--        idna.encode(instance)
--        return True
--
--
--try:
--    import rfc3987
--except ImportError:
--    try:
--        from rfc3986_validator import validate_rfc3986
--    except ImportError:
--        pass
--    else:
--        @_checks_drafts(name="uri")
--        def is_uri(instance):
--            if not isinstance(instance, str_types):
--                return True
--            return validate_rfc3986(instance, rule="URI")
--
--        @_checks_drafts(
--            draft6="uri-reference",
--            draft7="uri-reference",
--            raises=ValueError,
--        )
--        def is_uri_reference(instance):
--            if not isinstance(instance, str_types):
--                return True
--            return validate_rfc3986(instance, rule="URI_reference")
--
--else:
--    @_checks_drafts(draft7="iri", raises=ValueError)
--    def is_iri(instance):
--        if not isinstance(instance, str_types):
--            return True
--        return rfc3987.parse(instance, rule="IRI")
--
--    @_checks_drafts(draft7="iri-reference", raises=ValueError)
--    def is_iri_reference(instance):
--        if not isinstance(instance, str_types):
--            return True
--        return rfc3987.parse(instance, rule="IRI_reference")
--
--    @_checks_drafts(name="uri", raises=ValueError)
--    def is_uri(instance):
--        if not isinstance(instance, str_types):
--            return True
--        return rfc3987.parse(instance, rule="URI")
--
--    @_checks_drafts(
--        draft6="uri-reference",
--        draft7="uri-reference",
--        raises=ValueError,
--    )
--    def is_uri_reference(instance):
--        if not isinstance(instance, str_types):
--            return True
--        return rfc3987.parse(instance, rule="URI_reference")
--
--
--try:
--    from strict_rfc3339 import validate_rfc3339
--except ImportError:
--    try:
--        from rfc3339_validator import validate_rfc3339
--    except ImportError:
--        validate_rfc3339 = None
--
--if validate_rfc3339:
--    @_checks_drafts(name="date-time")
--    def is_datetime(instance):
--        if not isinstance(instance, str_types):
--            return True
--        return validate_rfc3339(instance)
--
--    @_checks_drafts(draft7="time")
--    def is_time(instance):
--        if not isinstance(instance, str_types):
--            return True
--        return is_datetime("1970-01-01T" + instance)
--
--
- @_checks_drafts(name="regex", raises=re.error)
- def is_regex(instance):
-     if not isinstance(instance, str_types):
-@@ -340,86 +250,3 @@ def is_draft3_time(instance):
-     if not isinstance(instance, str_types):
-         return True
-     return datetime.datetime.strptime(instance, "%H:%M:%S")
--
--
--try:
--    import webcolors
--except ImportError:
--    pass
--else:
--    def is_css_color_code(instance):
--        return webcolors.normalize_hex(instance)
--
--    @_checks_drafts(draft3="color", raises=(ValueError, TypeError))
--    def is_css21_color(instance):
--        if (
--            not isinstance(instance, str_types) or
--            instance.lower() in webcolors.css21_names_to_hex
--        ):
--            return True
--        return is_css_color_code(instance)
--
--    def is_css3_color(instance):
--        if instance.lower() in webcolors.css3_names_to_hex:
--            return True
--        return is_css_color_code(instance)
--
--
--try:
--    import jsonpointer
--except ImportError:
--    pass
--else:
--    @_checks_drafts(
--        draft6="json-pointer",
--        draft7="json-pointer",
--        raises=jsonpointer.JsonPointerException,
--    )
--    def is_json_pointer(instance):
--        if not isinstance(instance, str_types):
--            return True
--        return jsonpointer.JsonPointer(instance)
--
--    # TODO: I don't want to maintain this, so it
--    #       needs to go either into jsonpointer (pending
--    #       https://github.com/stefankoegl/python-json-pointer/issues/34) or
--    #       into a new external library.
--    @_checks_drafts(
--        draft7="relative-json-pointer",
--        raises=jsonpointer.JsonPointerException,
--    )
--    def is_relative_json_pointer(instance):
--        # Definition taken from:
--        # https://tools.ietf.org/html/draft-handrews-relative-json-pointer-01#section-3
--        if not isinstance(instance, str_types):
--            return True
--        non_negative_integer, rest = [], ""
--        for i, character in enumerate(instance):
--            if character.isdigit():
--                non_negative_integer.append(character)
--                continue
--
--            if not non_negative_integer:
--                return False
--
--            rest = instance[i:]
--            break
--        return (rest == "#") or jsonpointer.JsonPointer(rest)
--
--
--try:
--    import uritemplate.exceptions
--except ImportError:
--    pass
--else:
--    @_checks_drafts(
--        draft6="uri-template",
--        draft7="uri-template",
--        raises=uritemplate.exceptions.InvalidTemplate,
--    )
--    def is_uri_template(
--        instance,
--        template_validator=uritemplate.Validator().force_balanced_braces(),
--    ):
--        template = uritemplate.URITemplate(instance)
--        return template_validator.validate(template)

lib/spack/llnl/util/filesystem.py

@@ -1624,12 +1624,6 @@ def remove_linked_tree(path):
             shutil.rmtree(os.path.realpath(path), **kwargs)
             os.unlink(path)
         else:
-            if sys.platform == "win32":
-                # Adding this prefix allows shutil to remove long paths on windows
-                # https://learn.microsoft.com/en-us/windows/win32/fileio/maximum-file-path-limitation?tabs=registry
-                long_path_pfx = "\\\\?\\"
-                if not path.startswith(long_path_pfx):
-                    path = long_path_pfx + path
             shutil.rmtree(path, **kwargs)
 
 

lib/spack/llnl/util/lang.py

@@ -6,6 +6,7 @@
 import collections.abc
 import contextlib
 import functools
+import inspect
 import itertools
 import os
 import re
@@ -15,7 +16,7 @@
 from typing import Any, Callable, Iterable, List, Tuple
 
 # Ignore emacs backups when listing modules
-ignore_modules = r"^\.#|~$"
+ignore_modules = [r"^\.#", "~$"]
 
 
 def index_by(objects, *funcs):
@@ -83,6 +84,20 @@ def index_by(objects, *funcs):
     return result
 
 
+def caller_locals():
+    """This will return the locals of the *parent* of the caller.
+    This allows a function to insert variables into its caller's
+    scope.  Yes, this is some black magic, and yes it's useful
+    for implementing things like depends_on and provides.
+    """
+    # Passing zero here skips line context for speed.
+    stack = inspect.stack(0)
+    try:
+        return stack[2][0].f_locals
+    finally:
+        del stack
+
+
 def attr_setdefault(obj, name, value):
     """Like dict.setdefault, but for objects."""
     if not hasattr(obj, name):
@@ -90,6 +105,15 @@ def attr_setdefault(obj, name, value):
     return getattr(obj, name)
 
 
+def has_method(cls, name):
+    for base in inspect.getmro(cls):
+        if base is object:
+            continue
+        if name in base.__dict__:
+            return True
+    return False
+
+
 def union_dicts(*dicts):
     """Use update() to combine all dicts into one.
 
@@ -154,22 +178,19 @@ def list_modules(directory, **kwargs):
     order."""
     list_directories = kwargs.setdefault("directories", True)
 
-    ignore = re.compile(ignore_modules)
+    for name in os.listdir(directory):
+        if name == "__init__.py":
+            continue
 
-    with os.scandir(directory) as it:
-        for entry in it:
-            if entry.name == "__init__.py" or entry.name == "__pycache__":
-                continue
+        path = os.path.join(directory, name)
+        if list_directories and os.path.isdir(path):
+            init_py = os.path.join(path, "__init__.py")
+            if os.path.isfile(init_py):
+                yield name
 
-            if (
-                list_directories
-                and entry.is_dir()
-                and os.path.isfile(os.path.join(entry.path, "__init__.py"))
-            ):
-                yield entry.name
-
-            elif entry.name.endswith(".py") and entry.is_file() and not ignore.search(entry.name):
-                yield entry.name[:-3]  # strip .py
+        elif name.endswith(".py"):
+            if not any(re.search(pattern, name) for pattern in ignore_modules):
+                yield re.sub(".py$", "", name)
 
 
 def decorator_with_or_without_args(decorator):
@@ -216,8 +237,8 @@ def setter(name, value):
         value.__name__ = name
         setattr(cls, name, value)
 
-    if not hasattr(cls, "_cmp_key"):
-        raise TypeError(f"'{cls.__name__}' doesn't define _cmp_key().")
+    if not has_method(cls, "_cmp_key"):
+        raise TypeError("'%s' doesn't define _cmp_key()." % cls.__name__)
 
     setter("__eq__", lambda s, o: (s is o) or (o is not None and s._cmp_key() == o._cmp_key()))
     setter("__lt__", lambda s, o: o is not None and s._cmp_key() < o._cmp_key())
@@ -367,8 +388,8 @@ def cd_fun():
         TypeError: If the class does not have a ``_cmp_iter`` method
 
     """
-    if not hasattr(cls, "_cmp_iter"):
-        raise TypeError(f"'{cls.__name__}' doesn't define _cmp_iter().")
+    if not has_method(cls, "_cmp_iter"):
+        raise TypeError("'%s' doesn't define _cmp_iter()." % cls.__name__)
 
     # comparison operators are implemented in terms of lazy_eq and lazy_lt
     def eq(self, other):

lib/spack/llnl/util/tty/log.py

@@ -10,7 +10,6 @@
 import errno
 import io
 import multiprocessing
-import multiprocessing.connection
 import os
 import re
 import select

lib/spack/spack/abi.py

@@ -0,0 +1,131 @@
+# Copyright 2013-2024 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
+import os
+
+from llnl.util.lang import memoized
+
+import spack.spec
+import spack.version
+from spack.compilers.clang import Clang
+from spack.util.executable import Executable, ProcessError
+
+
+class ABI:
+    """This class provides methods to test ABI compatibility between specs.
+    The current implementation is rather rough and could be improved."""
+
+    def architecture_compatible(
+        self, target: spack.spec.Spec, constraint: spack.spec.Spec
+    ) -> bool:
+        """Return true if architecture of target spec is ABI compatible
+        to the architecture of constraint spec. If either the target
+        or constraint specs have no architecture, target is also defined
+        as architecture ABI compatible to constraint."""
+        return (
+            not target.architecture
+            or not constraint.architecture
+            or target.architecture.intersects(constraint.architecture)
+        )
+
+    @memoized
+    def _gcc_get_libstdcxx_version(self, version):
+        """Returns gcc ABI compatibility info by getting the library version of
+        a compiler's libstdc++ or libgcc_s"""
+        from spack.build_environment import dso_suffix
+
+        spec = spack.spec.CompilerSpec("gcc", version)
+        compilers = spack.compilers.compilers_for_spec(spec)
+        if not compilers:
+            return None
+        compiler = compilers[0]
+        rungcc = None
+        libname = None
+        output = None
+        if compiler.cxx:
+            rungcc = Executable(compiler.cxx)
+            libname = "libstdc++." + dso_suffix
+        elif compiler.cc:
+            rungcc = Executable(compiler.cc)
+            libname = "libgcc_s." + dso_suffix
+        else:
+            return None
+        try:
+            # Some gcc's are actually clang and don't respond properly to
+            # --print-file-name (they just print the filename, not the
+            # full path).  Ignore these and expect them to be handled as clang.
+            if Clang.default_version(rungcc.exe[0]) != "unknown":
+                return None
+
+            output = rungcc("--print-file-name=%s" % libname, output=str)
+        except ProcessError:
+            return None
+        if not output:
+            return None
+        libpath = os.path.realpath(output.strip())
+        if not libpath:
+            return None
+        return os.path.basename(libpath)
+
+    @memoized
+    def _gcc_compiler_compare(self, pversion, cversion):
+        """Returns true iff the gcc version pversion and cversion
+        are ABI compatible."""
+        plib = self._gcc_get_libstdcxx_version(pversion)
+        clib = self._gcc_get_libstdcxx_version(cversion)
+        if not plib or not clib:
+            return False
+        return plib == clib
+
+    def _intel_compiler_compare(
+        self, pversion: spack.version.ClosedOpenRange, cversion: spack.version.ClosedOpenRange
+    ) -> bool:
+        """Returns true iff the intel version pversion and cversion
+        are ABI compatible"""
+
+        # Test major and minor versions.  Ignore build version.
+        pv = pversion.lo
+        cv = cversion.lo
+        return pv.up_to(2) == cv.up_to(2)
+
+    def compiler_compatible(
+        self, parent: spack.spec.Spec, child: spack.spec.Spec, loose: bool = False
+    ) -> bool:
+        """Return true if compilers for parent and child are ABI compatible."""
+        if not parent.compiler or not child.compiler:
+            return True
+
+        if parent.compiler.name != child.compiler.name:
+            # Different compiler families are assumed ABI incompatible
+            return False
+
+        if loose:
+            return True
+
+        # TODO: Can we move the specialized ABI matching stuff
+        # TODO: into compiler classes?
+        for pversion in parent.compiler.versions:
+            for cversion in child.compiler.versions:
+                # For a few compilers use specialized comparisons.
+                # Otherwise match on version match.
+                if pversion.intersects(cversion):
+                    return True
+                elif parent.compiler.name == "gcc" and self._gcc_compiler_compare(
+                    pversion, cversion
+                ):
+                    return True
+                elif parent.compiler.name == "intel" and self._intel_compiler_compare(
+                    pversion, cversion
+                ):
+                    return True
+        return False
+
+    def compatible(
+        self, target: spack.spec.Spec, constraint: spack.spec.Spec, loose: bool = False
+    ) -> bool:
+        """Returns true if target spec is ABI compatible to constraint spec"""
+        return self.architecture_compatible(target, constraint) and self.compiler_compatible(
+            target, constraint, loose=loose
+        )

lib/spack/spack/audit.py

@@ -39,9 +39,9 @@ def _search_duplicate_compilers(error_cls):
 import collections
 import collections.abc
 import glob
+import inspect
 import io
 import itertools
-import os
 import pathlib
 import pickle
 import re
@@ -210,11 +210,6 @@ def _search_duplicate_compilers(error_cls):
     group="configs", tag="CFG-PACKAGES", description="Sanity checks on packages.yaml", kwargs=()
 )
 
-#: Sanity checks on packages.yaml
-config_repos = AuditClass(
-    group="configs", tag="CFG-REPOS", description="Sanity checks on repositories", kwargs=()
-)
-
 
 @config_packages
 def _search_duplicate_specs_in_externals(error_cls):
@@ -372,27 +367,6 @@ def _ensure_all_virtual_packages_have_default_providers(error_cls):
     ]
 
 
-@config_repos
-def _ensure_no_folders_without_package_py(error_cls):
-    """Check that we don't leave any folder without a package.py in repos"""
-    errors = []
-    for repository in spack.repo.PATH.repos:
-        missing = []
-        for entry in os.scandir(repository.packages_path):
-            if not entry.is_dir():
-                continue
-            package_py = pathlib.Path(entry.path) / spack.repo.package_file_name
-            if not package_py.exists():
-                missing.append(entry.path)
-        if missing:
-            summary = (
-                f"The '{repository.namespace}' repository misses a package.py file"
-                f" in the following folders"
-            )
-            errors.append(error_cls(summary=summary, details=[f"{x}" for x in missing]))
-    return errors
-
-
 def _make_config_error(config_data, summary, error_cls):
     s = io.StringIO()
     s.write("Occurring in the following file:\n")
@@ -524,7 +498,7 @@ def _search_for_reserved_attributes_names_in_packages(pkgs, error_cls):
         name_definitions = collections.defaultdict(list)
         pkg_cls = spack.repo.PATH.get_pkg_class(pkg_name)
 
-        for cls_item in pkg_cls.__mro__:
+        for cls_item in inspect.getmro(pkg_cls):
             for name in RESERVED_NAMES:
                 current_value = cls_item.__dict__.get(name)
                 if current_value is None:
@@ -553,7 +527,7 @@ def _ensure_all_package_names_are_lowercase(pkgs, error_cls):
     badname_regex, errors = re.compile(r"[_A-Z]"), []
     for pkg_name in pkgs:
         if badname_regex.search(pkg_name):
-            error_msg = f"Package name '{pkg_name}' should be lowercase and must not contain '_'"
+            error_msg = "Package name '{}' is either lowercase or conatine '_'".format(pkg_name)
             errors.append(error_cls(error_msg, []))
     return errors
 

lib/spack/spack/bootstrap/_common.py

@@ -4,7 +4,6 @@
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 """Common basic functions used through the spack.bootstrap package"""
 import fnmatch
-import importlib
 import os.path
 import re
 import sys
@@ -29,7 +28,7 @@
 
 def _python_import(module: str) -> bool:
     try:
-        importlib.import_module(module)
+        __import__(module)
     except ImportError:
         return False
     return True

lib/spack/spack/bootstrap/clingo.py

@@ -1,154 +0,0 @@
-# Copyright 2013-2024 Lawrence Livermore National Security, LLC and other
-# Spack Project Developers. See the top-level COPYRIGHT file for details.
-#
-# SPDX-License-Identifier: (Apache-2.0 OR MIT)
-"""Bootstrap concrete specs for clingo
-
-Spack uses clingo to concretize specs. When clingo itself needs to be bootstrapped from sources,
-we need to rely on another mechanism to get a concrete spec that fits the current host.
-
-This module contains the logic to get a concrete spec for clingo, starting from a prototype
-JSON file for a similar platform.
-"""
-import pathlib
-import sys
-from typing import Dict, Optional, Tuple
-
-import archspec.cpu
-
-import spack.compiler
-import spack.compilers
-import spack.platforms
-import spack.spec
-import spack.traverse
-
-from .config import spec_for_current_python
-
-
-class ClingoBootstrapConcretizer:
-    def __init__(self, configuration):
-        self.host_platform = spack.platforms.host()
-        self.host_os = self.host_platform.operating_system("frontend")
-        self.host_target = archspec.cpu.host().family
-        self.host_architecture = spack.spec.ArchSpec.frontend_arch()
-        self.host_architecture.target = str(self.host_target)
-        self.host_compiler = self._valid_compiler_or_raise()
-        self.host_python = self.python_external_spec()
-        if str(self.host_platform) == "linux":
-            self.host_libc = self.libc_external_spec()
-
-        self.external_cmake, self.external_bison = self._externals_from_yaml(configuration)
-
-    def _valid_compiler_or_raise(self) -> "spack.compiler.Compiler":
-        if str(self.host_platform) == "linux":
-            compiler_name = "gcc"
-        elif str(self.host_platform) == "darwin":
-            compiler_name = "apple-clang"
-        elif str(self.host_platform) == "windows":
-            compiler_name = "msvc"
-        elif str(self.host_platform) == "freebsd":
-            compiler_name = "clang"
-        else:
-            raise RuntimeError(f"Cannot bootstrap clingo from sources on {self.host_platform}")
-        candidates = spack.compilers.compilers_for_spec(
-            compiler_name, arch_spec=self.host_architecture
-        )
-        if not candidates:
-            raise RuntimeError(
-                f"Cannot find any version of {compiler_name} to bootstrap clingo from sources"
-            )
-        candidates.sort(key=lambda x: x.spec.version, reverse=True)
-        return candidates[0]
-
-    def _externals_from_yaml(
-        self, configuration: "spack.config.Configuration"
-    ) -> Tuple[Optional["spack.spec.Spec"], Optional["spack.spec.Spec"]]:
-        packages_yaml = configuration.get("packages")
-        requirements = {"cmake": "@3.20:", "bison": "@2.5:"}
-        selected: Dict[str, Optional["spack.spec.Spec"]] = {"cmake": None, "bison": None}
-        for pkg_name in ["cmake", "bison"]:
-            if pkg_name not in packages_yaml:
-                continue
-
-            candidates = packages_yaml[pkg_name].get("externals", [])
-            for candidate in candidates:
-                s = spack.spec.Spec(candidate["spec"], external_path=candidate["prefix"])
-                if not s.satisfies(requirements[pkg_name]):
-                    continue
-
-                if not s.intersects(f"%{self.host_compiler.spec}"):
-                    continue
-
-                if not s.intersects(f"arch={self.host_architecture}"):
-                    continue
-
-                selected[pkg_name] = self._external_spec(s)
-                break
-        return selected["cmake"], selected["bison"]
-
-    def prototype_path(self) -> pathlib.Path:
-        """Path to a prototype concrete specfile for clingo"""
-        parent_dir = pathlib.Path(__file__).parent
-        result = parent_dir / "prototypes" / f"clingo-{self.host_platform}-{self.host_target}.json"
-        if str(self.host_platform) == "linux":
-            # Using aarch64 as a fallback, since it has gnuconfig (x86_64 doesn't have it)
-            if not result.exists():
-                result = parent_dir / "prototypes" / f"clingo-{self.host_platform}-aarch64.json"
-
-        elif str(self.host_platform) == "freebsd":
-            result = parent_dir / "prototypes" / f"clingo-{self.host_platform}-amd64.json"
-
-        elif not result.exists():
-            raise RuntimeError(f"Cannot bootstrap clingo from sources on {self.host_platform}")
-
-        return result
-
-    def concretize(self) -> "spack.spec.Spec":
-        # Read the prototype and mark it NOT concrete
-        s = spack.spec.Spec.from_specfile(str(self.prototype_path()))
-        s._mark_concrete(False)
-
-        # Tweak it to conform to the host architecture
-        for node in s.traverse():
-            node.architecture.os = str(self.host_os)
-            node.compiler = self.host_compiler.spec
-            node.architecture = self.host_architecture
-
-            if node.name == "gcc-runtime":
-                node.versions = self.host_compiler.spec.versions
-
-        for edge in spack.traverse.traverse_edges([s], cover="edges"):
-            if edge.spec.name == "python":
-                edge.spec = self.host_python
-
-            if edge.spec.name == "bison" and self.external_bison:
-                edge.spec = self.external_bison
-
-            if edge.spec.name == "cmake" and self.external_cmake:
-                edge.spec = self.external_cmake
-
-            if "libc" in edge.virtuals:
-                edge.spec = self.host_libc
-
-        s._finalize_concretization()
-
-        # Work around the fact that the installer calls Spec.dependents() and
-        # we modified edges inconsistently
-        return s.copy()
-
-    def python_external_spec(self) -> "spack.spec.Spec":
-        """Python external spec corresponding to the current running interpreter"""
-        result = spack.spec.Spec(spec_for_current_python(), external_path=sys.exec_prefix)
-        return self._external_spec(result)
-
-    def libc_external_spec(self) -> "spack.spec.Spec":
-        result = self.host_compiler.default_libc
-        return self._external_spec(result)
-
-    def _external_spec(self, initial_spec) -> "spack.spec.Spec":
-        initial_spec.namespace = "builtin"
-        initial_spec.compiler = self.host_compiler.spec
-        initial_spec.architecture = self.host_architecture
-        for flag_type in spack.spec.FlagMap.valid_compiler_flags():
-            initial_spec.compiler_flags[flag_type] = []
-        return spack.spec.parse_with_version_concrete(initial_spec)

lib/spack/spack/bootstrap/config.py

@@ -143,7 +143,11 @@ def _bootstrap_config_scopes() -> Sequence["spack.config.ConfigScope"]:
 def _add_compilers_if_missing() -> None:
     arch = spack.spec.ArchSpec.frontend_arch()
     if not spack.compilers.compilers_for_arch(arch):
-        spack.compilers.find_compilers()
+        new_compilers = spack.compilers.find_new_compilers(
+            mixed_toolchain=sys.platform == "darwin"
+        )
+        if new_compilers:
+            spack.compilers.add_compilers_to_config(new_compilers)
 
 
 @contextlib.contextmanager
@@ -152,7 +156,7 @@ def _ensure_bootstrap_configuration() -> Generator:
     bootstrap_store_path = store_path()
     user_configuration = _read_and_sanitize_configuration()
     with spack.environment.no_active_environment():
-        with spack.platforms.use_platform(
+        with spack.platforms.prevent_cray_detection(), spack.platforms.use_platform(
             spack.platforms.real_host()
         ), spack.repo.use_repositories(spack.paths.packages_path):
             # Default configuration scopes excluding command line

lib/spack/spack/bootstrap/core.py

@@ -54,7 +54,6 @@
 import spack.version
 
 from ._common import _executables_in_store, _python_import, _root_spec, _try_import_from_store
-from .clingo import ClingoBootstrapConcretizer
 from .config import spack_python_interpreter, spec_for_current_python
 
 #: Name of the file containing metadata about the bootstrapping source
@@ -269,13 +268,15 @@ def try_import(self, module: str, abstract_spec_str: str) -> bool:
 
         # Try to build and install from sources
         with spack_python_interpreter():
+            # Add hint to use frontend operating system on Cray
+            concrete_spec = spack.spec.Spec(abstract_spec_str + " ^" + spec_for_current_python())
+
             if module == "clingo":
-                bootstrapper = ClingoBootstrapConcretizer(configuration=spack.config.CONFIG)
-                concrete_spec = bootstrapper.concretize()
-            else:
-                concrete_spec = spack.spec.Spec(
-                    abstract_spec_str + " ^" + spec_for_current_python()
+                # TODO: remove when the old concretizer is deprecated  # pylint: disable=fixme
+                concrete_spec._old_concretize(  # pylint: disable=protected-access
+                    deprecation_warning=False
                 )
+            else:
                 concrete_spec.concretize()
 
         msg = "[BOOTSTRAP MODULE {0}] Try installing '{1}' from sources"
@@ -302,7 +303,14 @@ def try_search_path(self, executables: Tuple[str], abstract_spec_str: str) -> bo
         # might reduce compilation time by a fair amount
         _add_externals_if_missing()
 
-        concrete_spec = spack.spec.Spec(abstract_spec_str).concretized()
+        concrete_spec = spack.spec.Spec(abstract_spec_str)
+        if concrete_spec.name == "patchelf":
+            concrete_spec._old_concretize(  # pylint: disable=protected-access
+                deprecation_warning=False
+            )
+        else:
+            concrete_spec.concretize()
+
         msg = "[BOOTSTRAP] Try installing '{0}' from sources"
         tty.debug(msg.format(abstract_spec_str))
         with spack.config.override(self.mirror_scope):

lib/spack/spack/bootstrap/status.py

@@ -124,7 +124,7 @@ def _development_requirements() -> List[RequiredResponseType]:
     # Ensure we trigger environment modifications if we have an environment
     if BootstrapEnvironment.spack_yaml().exists():
         with BootstrapEnvironment() as env:
-            env.load()
+            env.update_syspath_and_environ()
 
     return [
         _required_executable(

lib/spack/spack/build_environment.py

@@ -457,12 +457,9 @@ def set_wrapper_variables(pkg, env):
     env.set(SPACK_DEBUG_LOG_ID, pkg.spec.format("{name}-{hash:7}"))
     env.set(SPACK_DEBUG_LOG_DIR, spack.main.spack_working_dir)
 
+    # Find ccache binary and hand it to build environment
     if spack.config.get("config:ccache"):
-        # Enable ccache in the compiler wrapper
         env.set(SPACK_CCACHE_BINARY, spack.util.executable.which_string("ccache", required=True))
-    else:
-        # Avoid cache pollution if a build system forces `ccache <compiler wrapper invocation>`.
-        env.set("CCACHE_DISABLE", "1")
 
     # Gather information about various types of dependencies
     link_deps = set(pkg.spec.traverse(root=False, deptype=("link")))
@@ -555,7 +552,7 @@ def set_package_py_globals(pkg, context: Context = Context.BUILD):
     """Populate the Python module of a package with some useful global names.
     This makes things easier for package writers.
     """
-    module = SetPackageGlobals(pkg)
+    module = ModuleChangePropagator(pkg)
 
     if context == Context.BUILD:
         module.std_cmake_args = spack.build_systems.cmake.CMakeBuilder.std_args(pkg)
@@ -1016,7 +1013,7 @@ def set_all_package_py_globals(self):
                 # setting globals for those.
                 if id(spec) not in self.nodes_in_subdag:
                     continue
-                dependent_module = SetPackageGlobals(spec.package)
+                dependent_module = ModuleChangePropagator(spec.package)
                 pkg.setup_dependent_package(dependent_module, spec)
                 dependent_module.propagate_changes_to_mro()
 
@@ -1543,7 +1540,7 @@ def write_log_summary(out, log_type, log, last=None):
         out.write(make_log_context(warnings))
 
 
-class SetPackageGlobals:
+class ModuleChangePropagator:
     """Wrapper class to accept changes to a package.py Python module, and propagate them in the
     MRO of the package.
 
@@ -1551,22 +1548,41 @@ class SetPackageGlobals:
     "setup_dependent_package" function during build environment setup.
     """
 
-    def __init__(self, package: spack.package_base.PackageBase) -> None:
+    _PROTECTED_NAMES = ("package", "current_module", "modules_in_mro", "_set_attributes")
+
+    def __init__(self, package):
+        self._set_self_attributes("package", package)
+        self._set_self_attributes("current_module", package.module)
+
         #: Modules for the classes in the MRO up to PackageBase
         modules_in_mro = []
-        for cls in package.__class__.__mro__:
-            module = getattr(cls, "module", None)
-            if module is None or module is spack.package_base:
-                break
-            modules_in_mro.append(module)
+        for cls in inspect.getmro(type(package)):
+            module = cls.module
 
-        super().__setattr__("modules_in_mro", modules_in_mro)
+            if module == self.current_module:
+                continue
+
+            if module == spack.package_base:
+                break
+
+            modules_in_mro.append(module)
+        self._set_self_attributes("modules_in_mro", modules_in_mro)
+        self._set_self_attributes("_set_attributes", {})
+
+    def _set_self_attributes(self, key, value):
+        super().__setattr__(key, value)
 
     def __getattr__(self, item):
-        return getattr(self.modules_in_mro[0], item)
+        return getattr(self.current_module, item)
 
     def __setattr__(self, key, value):
-        if key == "modules_in_mro":
-            raise AttributeError(f'Cannot set attribute "{key}" in ModuleMonkeyPatcher')
-        for module in self.modules_in_mro:
-            setattr(module, key, value)
+        if key in ModuleChangePropagator._PROTECTED_NAMES:
+            msg = f'Cannot set attribute "{key}" in ModuleMonkeyPatcher'
+            return AttributeError(msg)
+
+        setattr(self.current_module, key, value)
+        self._set_attributes[key] = value
+
+    def propagate_changes_to_mro(self):
+        for module_in_mro in self.modules_in_mro:
+            module_in_mro.__dict__.update(self._set_attributes)

lib/spack/spack/build_systems/autotools.py

@@ -2,6 +2,7 @@
 # Spack Project Developers. See the top-level COPYRIGHT file for details.
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
+import inspect
 import os
 import os.path
 import stat
@@ -14,7 +15,6 @@
 import spack.build_environment
 import spack.builder
 import spack.package_base
-from spack.build_environment import SetPackageGlobals
 from spack.directives import build_system, conflicts, depends_on
 from spack.multimethod import when
 from spack.operating_systems.mac_os import macos_version
@@ -549,12 +549,13 @@ def autoreconf(self, pkg, spec, prefix):
         tty.warn("*        a custom AUTORECONF phase in the package       *")
         tty.warn("*********************************************************")
         with fs.working_dir(self.configure_directory):
+            m = inspect.getmodule(self.pkg)
             # This line is what is needed most of the time
             # --install, --verbose, --force
             autoreconf_args = ["-ivf"]
             autoreconf_args += self.autoreconf_search_path_args
             autoreconf_args += self.autoreconf_extra_args
-            self.pkg.module.autoreconf(*autoreconf_args)
+            m.autoreconf(*autoreconf_args)
 
     @property
     def autoreconf_search_path_args(self):
@@ -578,7 +579,7 @@ def set_configure_or_die(self):
             raise RuntimeError(msg.format(self.configure_directory))
 
         # Monkey-patch the configure script in the corresponding module
-        SetPackageGlobals(self.pkg).configure = Executable(self.configure_abs_path)
+        inspect.getmodule(self.pkg).configure = Executable(self.configure_abs_path)
 
     def configure_args(self):
         """Return the list of all the arguments that must be passed to configure,
@@ -595,7 +596,7 @@ def configure(self, pkg, spec, prefix):
         options += self.configure_args()
 
         with fs.working_dir(self.build_directory, create=True):
-            pkg.module.configure(*options)
+            inspect.getmodule(self.pkg).configure(*options)
 
     def build(self, pkg, spec, prefix):
         """Run "make" on the build targets specified by the builder."""
@@ -603,12 +604,12 @@ def build(self, pkg, spec, prefix):
         params = ["V=1"]
         params += self.build_targets
         with fs.working_dir(self.build_directory):
-            pkg.module.make(*params)
+            inspect.getmodule(self.pkg).make(*params)
 
     def install(self, pkg, spec, prefix):
         """Run "make" on the install targets specified by the builder."""
         with fs.working_dir(self.build_directory):
-            pkg.module.make(*self.install_targets)
+            inspect.getmodule(self.pkg).make(*self.install_targets)
 
     spack.builder.run_after("build")(execute_build_time_tests)
 

lib/spack/spack/build_systems/cargo.py

@@ -3,6 +3,8 @@
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 
+import inspect
+
 import llnl.util.filesystem as fs
 
 import spack.builder
@@ -70,7 +72,9 @@ def check_args(self):
     def build(self, pkg, spec, prefix):
         """Runs ``cargo install`` in the source directory"""
         with fs.working_dir(self.build_directory):
-            pkg.module.cargo("install", "--root", "out", "--path", ".", *self.build_args)
+            inspect.getmodule(pkg).cargo(
+                "install", "--root", "out", "--path", ".", *self.build_args
+            )
 
     def install(self, pkg, spec, prefix):
         """Copy build files into package prefix."""
@@ -82,4 +86,4 @@ def install(self, pkg, spec, prefix):
     def check(self):
         """Run "cargo test"."""
         with fs.working_dir(self.build_directory):
-            self.pkg.module.cargo("test", *self.check_args)
+            inspect.getmodule(self.pkg).cargo("test", *self.check_args)

lib/spack/spack/build_systems/cmake.py

@@ -3,6 +3,7 @@
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 import collections.abc
+import inspect
 import os
 import pathlib
 import platform
@@ -538,24 +539,24 @@ def cmake(self, pkg, spec, prefix):
         options += self.cmake_args()
         options.append(os.path.abspath(self.root_cmakelists_dir))
         with fs.working_dir(self.build_directory, create=True):
-            pkg.module.cmake(*options)
+            inspect.getmodule(self.pkg).cmake(*options)
 
     def build(self, pkg, spec, prefix):
         """Make the build targets"""
         with fs.working_dir(self.build_directory):
             if self.generator == "Unix Makefiles":
-                pkg.module.make(*self.build_targets)
+                inspect.getmodule(self.pkg).make(*self.build_targets)
             elif self.generator == "Ninja":
                 self.build_targets.append("-v")
-                pkg.module.ninja(*self.build_targets)
+                inspect.getmodule(self.pkg).ninja(*self.build_targets)
 
     def install(self, pkg, spec, prefix):
         """Make the install targets"""
         with fs.working_dir(self.build_directory):
             if self.generator == "Unix Makefiles":
-                pkg.module.make(*self.install_targets)
+                inspect.getmodule(self.pkg).make(*self.install_targets)
             elif self.generator == "Ninja":
-                pkg.module.ninja(*self.install_targets)
+                inspect.getmodule(self.pkg).ninja(*self.install_targets)
 
     spack.builder.run_after("build")(execute_build_time_tests)
 

lib/spack/spack/build_systems/cuda.py

@@ -138,14 +138,14 @@ def cuda_flags(arch_list):
         conflicts("%gcc@11.2:", when="+cuda ^cuda@:11.5")
         conflicts("%gcc@12:", when="+cuda ^cuda@:11.8")
         conflicts("%gcc@13:", when="+cuda ^cuda@:12.3")
-        conflicts("%gcc@14:", when="+cuda ^cuda@:12.6")
+        conflicts("%gcc@14:", when="+cuda ^cuda@:12.5")
         conflicts("%clang@12:", when="+cuda ^cuda@:11.4.0")
         conflicts("%clang@13:", when="+cuda ^cuda@:11.5")
         conflicts("%clang@14:", when="+cuda ^cuda@:11.7")
         conflicts("%clang@15:", when="+cuda ^cuda@:12.0")
         conflicts("%clang@16:", when="+cuda ^cuda@:12.1")
         conflicts("%clang@17:", when="+cuda ^cuda@:12.3")
-        conflicts("%clang@18:", when="+cuda ^cuda@:12.6")
+        conflicts("%clang@18:", when="+cuda ^cuda@:12.5")
 
         # https://gist.github.com/ax3l/9489132#gistcomment-3860114
         conflicts("%gcc@10", when="+cuda ^cuda@:11.4.0")

lib/spack/spack/build_systems/go.py

@@ -3,6 +3,8 @@
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 
+import inspect
+
 import llnl.util.filesystem as fs
 
 import spack.builder
@@ -80,7 +82,7 @@ def check_args(self):
     def build(self, pkg, spec, prefix):
         """Runs ``go build`` in the source directory"""
         with fs.working_dir(self.build_directory):
-            pkg.module.go("build", *self.build_args)
+            inspect.getmodule(pkg).go("build", *self.build_args)
 
     def install(self, pkg, spec, prefix):
         """Install built binaries into prefix bin."""
@@ -93,4 +95,4 @@ def install(self, pkg, spec, prefix):
     def check(self):
         """Run ``go test .`` in the source directory"""
         with fs.working_dir(self.build_directory):
-            self.pkg.module.go("test", *self.check_args)
+            inspect.getmodule(self.pkg).go("test", *self.check_args)

lib/spack/spack/build_systems/makefile.py

@@ -2,6 +2,7 @@
 # Spack Project Developers. See the top-level COPYRIGHT file for details.
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
+import inspect
 from typing import List
 
 import llnl.util.filesystem as fs
@@ -102,12 +103,12 @@ def edit(self, pkg, spec, prefix):
     def build(self, pkg, spec, prefix):
         """Run "make" on the build targets specified by the builder."""
         with fs.working_dir(self.build_directory):
-            pkg.module.make(*self.build_targets)
+            inspect.getmodule(self.pkg).make(*self.build_targets)
 
     def install(self, pkg, spec, prefix):
         """Run "make" on the install targets specified by the builder."""
         with fs.working_dir(self.build_directory):
-            pkg.module.make(*self.install_targets)
+            inspect.getmodule(self.pkg).make(*self.install_targets)
 
     spack.builder.run_after("build")(execute_build_time_tests)
 

lib/spack/spack/build_systems/meson.py

@@ -2,6 +2,7 @@
 # Spack Project Developers. See the top-level COPYRIGHT file for details.
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
+import inspect
 import os
 from typing import List
 
@@ -194,19 +195,19 @@ def meson(self, pkg, spec, prefix):
         options += self.std_meson_args
         options += self.meson_args()
         with fs.working_dir(self.build_directory, create=True):
-            pkg.module.meson(*options)
+            inspect.getmodule(self.pkg).meson(*options)
 
     def build(self, pkg, spec, prefix):
         """Make the build targets"""
         options = ["-v"]
         options += self.build_targets
         with fs.working_dir(self.build_directory):
-            pkg.module.ninja(*options)
+            inspect.getmodule(self.pkg).ninja(*options)
 
     def install(self, pkg, spec, prefix):
         """Make the install targets"""
         with fs.working_dir(self.build_directory):
-            pkg.module.ninja(*self.install_targets)
+            inspect.getmodule(self.pkg).ninja(*self.install_targets)
 
     spack.builder.run_after("build")(execute_build_time_tests)
 

lib/spack/spack/build_systems/msbuild.py

@@ -2,6 +2,7 @@
 # Spack Project Developers. See the top-level COPYRIGHT file for details.
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
+import inspect
 from typing import List  # novm
 
 import llnl.util.filesystem as fs
@@ -103,7 +104,7 @@ def msbuild_install_args(self):
     def build(self, pkg, spec, prefix):
         """Run "msbuild" on the build targets specified by the builder."""
         with fs.working_dir(self.build_directory):
-            pkg.module.msbuild(
+            inspect.getmodule(self.pkg).msbuild(
                 *self.std_msbuild_args,
                 *self.msbuild_args(),
                 self.define_targets(*self.build_targets),
@@ -113,6 +114,6 @@ def install(self, pkg, spec, prefix):
         """Run "msbuild" on the install targets specified by the builder.
         This is INSTALL by default"""
         with fs.working_dir(self.build_directory):
-            pkg.module.msbuild(
+            inspect.getmodule(self.pkg).msbuild(
                 *self.msbuild_install_args(), self.define_targets(*self.install_targets)
             )

lib/spack/spack/build_systems/nmake.py

@@ -2,6 +2,7 @@
 # Spack Project Developers. See the top-level COPYRIGHT file for details.
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
+import inspect
 from typing import List  # novm
 
 import llnl.util.filesystem as fs
@@ -131,7 +132,9 @@ def build(self, pkg, spec, prefix):
         if self.makefile_name:
             opts.append("/F{}".format(self.makefile_name))
         with fs.working_dir(self.build_directory):
-            pkg.module.nmake(*opts, *self.build_targets, ignore_quotes=self.ignore_quotes)
+            inspect.getmodule(self.pkg).nmake(
+                *opts, *self.build_targets, ignore_quotes=self.ignore_quotes
+            )
 
     def install(self, pkg, spec, prefix):
         """Run "nmake" on the install targets specified by the builder.
@@ -143,4 +146,6 @@ def install(self, pkg, spec, prefix):
             opts.append("/F{}".format(self.makefile_name))
         opts.append(self.define("PREFIX", fs.windows_sfn(prefix)))
         with fs.working_dir(self.build_directory):
-            pkg.module.nmake(*opts, *self.install_targets, ignore_quotes=self.ignore_quotes)
+            inspect.getmodule(self.pkg).nmake(
+                *opts, *self.install_targets, ignore_quotes=self.ignore_quotes
+            )

lib/spack/spack/build_systems/octave.py

@@ -2,6 +2,8 @@
 # Spack Project Developers. See the top-level COPYRIGHT file for details.
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
+import inspect
+
 import spack.builder
 import spack.package_base
 from spack.directives import build_system, extends
@@ -45,7 +47,7 @@ class OctaveBuilder(BaseBuilder):
 
     def install(self, pkg, spec, prefix):
         """Install the package from the archive file"""
-        pkg.module.octave(
+        inspect.getmodule(self.pkg).octave(
             "--quiet",
             "--norc",
             "--built-in-docstrings-file=/dev/null",

lib/spack/spack/build_systems/oneapi.py

@@ -3,6 +3,7 @@
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 """Common utilities for managing intel oneapi packages."""
+import getpass
 import os
 import platform
 import shutil
@@ -12,7 +13,6 @@
 from llnl.util.filesystem import HeaderList, LibraryList, find_libraries, join_path, mkdirp
 from llnl.util.link_tree import LinkTree
 
-import spack.util.path
 from spack.build_environment import dso_suffix
 from spack.directives import conflicts, license, redistribute, variant
 from spack.package_base import InstallError
@@ -99,7 +99,7 @@ def install_component(self, installer_path):
             # with other install depends on the userid. For root, we
             # delete the installercache before and after install. For
             # non root we redefine the HOME environment variable.
-            if spack.util.path.get_user() == "root":
+            if getpass.getuser() == "root":
                 shutil.rmtree("/var/intel/installercache", ignore_errors=True)
 
             bash = Executable("bash")
@@ -122,7 +122,7 @@ def install_component(self, installer_path):
                 self.prefix,
             )
 
-            if spack.util.path.get_user() == "root":
+            if getpass.getuser() == "root":
                 shutil.rmtree("/var/intel/installercache", ignore_errors=True)
 
         # Some installers have a bug and do not return an error code when failing

lib/spack/spack/build_systems/perl.py

@@ -2,6 +2,7 @@
 # Spack Project Developers. See the top-level COPYRIGHT file for details.
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
+import inspect
 import os
 from typing import Iterable
 
@@ -133,7 +134,7 @@ def build_method(self):
     def build_executable(self):
         """Returns the executable method to build the perl package"""
         if self.build_method == "Makefile.PL":
-            build_executable = self.pkg.module.make
+            build_executable = inspect.getmodule(self.pkg).make
         elif self.build_method == "Build.PL":
             build_executable = Executable(os.path.join(self.pkg.stage.source_path, "Build"))
         return build_executable
@@ -157,7 +158,7 @@ def configure(self, pkg, spec, prefix):
             options = ["Build.PL", "--install_base", prefix]
         options += self.configure_args()
 
-        pkg.module.perl(*options)
+        inspect.getmodule(self.pkg).perl(*options)
 
     # It is possible that the shebang in the Build script that is created from
     # Build.PL may be too long causing the build to fail. Patching the shebang

lib/spack/spack/build_systems/python.py

@@ -4,6 +4,7 @@
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 
 import functools
+import inspect
 import operator
 import os
 import re
@@ -16,7 +17,7 @@
 import llnl.util.filesystem as fs
 import llnl.util.lang as lang
 import llnl.util.tty as tty
-from llnl.util.filesystem import HeaderList, LibraryList, join_path
+from llnl.util.filesystem import HeaderList, LibraryList
 
 import spack.builder
 import spack.config
@@ -119,12 +120,6 @@ def skip_modules(self) -> Iterable[str]:
         """
         return []
 
-    @property
-    def bindir(self) -> str:
-        """Path to Python package's bindir, bin on unix like OS's Scripts on Windows"""
-        windows = self.spec.satisfies("platform=windows")
-        return join_path(self.spec.prefix, "Scripts" if windows else "bin")
-
     def view_file_conflicts(self, view, merge_map):
         """Report all file conflicts, excepting special cases for python.
         Specifically, this does not report errors for duplicate
@@ -227,7 +222,7 @@ def test_imports(self) -> None:
 
         # Make sure we are importing the installed modules,
         # not the ones in the source directory
-        python = self.module.python
+        python = inspect.getmodule(self).python  # type: ignore[union-attr]
         for module in self.import_modules:
             with test_part(
                 self,
@@ -359,10 +354,18 @@ def homepage(cls) -> Optional[str]:  # type: ignore[override]
         return None
 
     @lang.classproperty
-    def url(cls) -> Optional[str]:
+    def urls(cls) -> Optional[List[str]]:
         if cls.pypi:
-            return f"https://files.pythonhosted.org/packages/source/{cls.pypi[0]}/{cls.pypi}"
-        return None
+            urls = [f"https://files.pythonhosted.org/packages/source/{cls.pypi[0]}/{cls.pypi}"]
+            assert cls.pypi.count("/") == 1, "PyPI class attribute must include a single slash"
+            name, file = cls.pypi.split("/")
+            name_dash_count = name.count("-")
+            if name_dash_count > 0:
+                # replace all but last dash with underscores for pypi.org listing changes
+                pypi = "/".join([name, file.replace("-", "_", name_dash_count)])
+                urls.append(f"https://files.pythonhosted.org/packages/source/{pypi[0]}/{pypi}")
+            return urls
+        return [None]
 
     @lang.classproperty
     def list_url(cls) -> Optional[str]:  # type: ignore[override]

lib/spack/spack/build_systems/qmake.py

@@ -2,6 +2,8 @@
 # Spack Project Developers. See the top-level COPYRIGHT file for details.
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
+import inspect
+
 from llnl.util.filesystem import working_dir
 
 import spack.builder
@@ -64,17 +66,17 @@ def qmake_args(self):
     def qmake(self, pkg, spec, prefix):
         """Run ``qmake`` to configure the project and generate a Makefile."""
         with working_dir(self.build_directory):
-            pkg.module.qmake(*self.qmake_args())
+            inspect.getmodule(self.pkg).qmake(*self.qmake_args())
 
     def build(self, pkg, spec, prefix):
         """Make the build targets"""
         with working_dir(self.build_directory):
-            pkg.module.make()
+            inspect.getmodule(self.pkg).make()
 
     def install(self, pkg, spec, prefix):
         """Make the install targets"""
         with working_dir(self.build_directory):
-            pkg.module.make("install")
+            inspect.getmodule(self.pkg).make("install")
 
     def check(self):
         """Search the Makefile for a ``check:`` target and runs it if found."""

lib/spack/spack/build_systems/r.py

@@ -2,6 +2,7 @@
 # Spack Project Developers. See the top-level COPYRIGHT file for details.
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
+import inspect
 from typing import Optional, Tuple
 
 import llnl.util.lang as lang
@@ -50,7 +51,7 @@ def install(self, pkg, spec, prefix):
 
         args.extend(["--library={0}".format(self.pkg.module.r_lib_dir), self.stage.source_path])
 
-        pkg.module.R(*args)
+        inspect.getmodule(self.pkg).R(*args)
 
 
 class RPackage(Package):

lib/spack/spack/build_systems/ruby.py

@@ -3,6 +3,7 @@
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 import glob
+import inspect
 
 import spack.builder
 import spack.package_base
@@ -51,10 +52,10 @@ def build(self, pkg, spec, prefix):
         gemspecs = glob.glob("*.gemspec")
         rakefiles = glob.glob("Rakefile")
         if gemspecs:
-            pkg.module.gem("build", "--norc", gemspecs[0])
+            inspect.getmodule(self.pkg).gem("build", "--norc", gemspecs[0])
         elif rakefiles:
-            jobs = pkg.module.make_jobs
-            pkg.module.rake("package", "-j{0}".format(jobs))
+            jobs = inspect.getmodule(self.pkg).make_jobs
+            inspect.getmodule(self.pkg).rake("package", "-j{0}".format(jobs))
         else:
             # Some Ruby packages only ship `*.gem` files, so nothing to build
             pass
@@ -69,6 +70,6 @@ def install(self, pkg, spec, prefix):
             # if --install-dir is not used, GEM_PATH is deleted from the
             # environement, and Gems required to build native extensions will
             # not be found. Those extensions are built during `gem install`.
-            pkg.module.gem(
+            inspect.getmodule(self.pkg).gem(
                 "install", "--norc", "--ignore-dependencies", "--install-dir", prefix, gems[0]
             )

lib/spack/spack/build_systems/scons.py

@@ -2,6 +2,8 @@
 # Spack Project Developers. See the top-level COPYRIGHT file for details.
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
+import inspect
+
 import spack.builder
 import spack.package_base
 from spack.directives import build_system, depends_on
@@ -61,7 +63,8 @@ def build_args(self, spec, prefix):
 
     def build(self, pkg, spec, prefix):
         """Build the package."""
-        pkg.module.scons(*self.build_args(spec, prefix))
+        args = self.build_args(spec, prefix)
+        inspect.getmodule(self.pkg).scons(*args)
 
     def install_args(self, spec, prefix):
         """Arguments to pass to install."""
@@ -69,7 +72,9 @@ def install_args(self, spec, prefix):
 
     def install(self, pkg, spec, prefix):
         """Install the package."""
-        pkg.module.scons("install", *self.install_args(spec, prefix))
+        args = self.install_args(spec, prefix)
+
+        inspect.getmodule(self.pkg).scons("install", *args)
 
     def build_test(self):
         """Run unit tests after build.

lib/spack/spack/build_systems/sip.py

@@ -2,6 +2,7 @@
 # Spack Project Developers. See the top-level COPYRIGHT file for details.
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
+import inspect
 import os
 import re
 
@@ -85,13 +86,14 @@ def import_modules(self):
 
     def python(self, *args, **kwargs):
         """The python ``Executable``."""
-        self.pkg.module.python(*args, **kwargs)
+        inspect.getmodule(self).python(*args, **kwargs)
 
     def test_imports(self):
         """Attempts to import modules of the installed package."""
 
         # Make sure we are importing the installed modules,
         # not the ones in the source directory
+        python = inspect.getmodule(self).python
         for module in self.import_modules:
             with spack.install_test.test_part(
                 self,
@@ -99,7 +101,7 @@ def test_imports(self):
                 purpose="checking import of {0}".format(module),
                 work_dir="spack-test",
             ):
-                self.python("-c", "import {0}".format(module))
+                python("-c", "import {0}".format(module))
 
 
 @spack.builder.builder("sip")
@@ -134,7 +136,7 @@ def configure(self, pkg, spec, prefix):
         """Configure the package."""
 
         # https://www.riverbankcomputing.com/static/Docs/sip/command_line_tools.html
-        args = ["--verbose", "--target-dir", pkg.module.python_platlib]
+        args = ["--verbose", "--target-dir", inspect.getmodule(self.pkg).python_platlib]
         args.extend(self.configure_args())
 
         # https://github.com/Python-SIP/sip/commit/cb0be6cb6e9b756b8b0db3136efb014f6fb9b766
@@ -153,7 +155,7 @@ def build(self, pkg, spec, prefix):
         args = self.build_args()
 
         with working_dir(self.build_directory):
-            pkg.module.make(*args)
+            inspect.getmodule(self.pkg).make(*args)
 
     def build_args(self):
         """Arguments to pass to build."""
@@ -164,7 +166,7 @@ def install(self, pkg, spec, prefix):
         args = self.install_args()
 
         with working_dir(self.build_directory):
-            pkg.module.make("install", *args)
+            inspect.getmodule(self.pkg).make("install", *args)
 
     def install_args(self):
         """Arguments to pass to install."""

lib/spack/spack/build_systems/waf.py

@@ -2,6 +2,8 @@
 # Spack Project Developers. See the top-level COPYRIGHT file for details.
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
+import inspect
+
 from llnl.util.filesystem import working_dir
 
 import spack.builder
@@ -88,11 +90,11 @@ def build_directory(self):
 
     def python(self, *args, **kwargs):
         """The python ``Executable``."""
-        self.pkg.module.python(*args, **kwargs)
+        inspect.getmodule(self.pkg).python(*args, **kwargs)
 
     def waf(self, *args, **kwargs):
         """Runs the waf ``Executable``."""
-        jobs = self.pkg.module.make_jobs
+        jobs = inspect.getmodule(self.pkg).make_jobs
 
         with working_dir(self.build_directory):
             self.python("waf", "-j{0}".format(jobs), *args, **kwargs)

lib/spack/spack/builder.py

@@ -6,12 +6,12 @@
 import collections.abc
 import copy
 import functools
+import inspect
 from typing import List, Optional, Tuple
 
 from llnl.util import lang
 
 import spack.build_environment
-import spack.multimethod
 
 #: Builder classes, as registered by the "builder" decorator
 BUILDER_CLS = {}
@@ -96,10 +96,11 @@ class hierarchy (look at AspellDictPackage for an example of that)
     Args:
         pkg (spack.package_base.PackageBase): package object for which we need a builder
     """
+    package_module = inspect.getmodule(pkg)
     package_buildsystem = buildsystem_name(pkg)
     default_builder_cls = BUILDER_CLS[package_buildsystem]
     builder_cls_name = default_builder_cls.__name__
-    builder_cls = getattr(pkg.module, builder_cls_name, None)
+    builder_cls = getattr(package_module, builder_cls_name, None)
     if builder_cls:
         return builder_cls(pkg)
 
@@ -294,11 +295,7 @@ def _decorator(fn):
         return _decorator
 
 
-class BuilderMeta(
-    PhaseCallbacksMeta,
-    spack.multimethod.MultiMethodMeta,
-    type(collections.abc.Sequence),  # type: ignore
-):
+class BuilderMeta(PhaseCallbacksMeta, type(collections.abc.Sequence)):  # type: ignore
     pass
 
 

lib/spack/spack/caches.py

@@ -9,11 +9,11 @@
 
 import llnl.util.lang
 from llnl.util.filesystem import mkdirp
+from llnl.util.symlink import symlink
 
 import spack.config
 import spack.error
 import spack.fetch_strategy
-import spack.mirror
 import spack.paths
 import spack.util.file_cache
 import spack.util.path
@@ -74,6 +74,23 @@ def store(self, fetcher, relative_dest):
         mkdirp(os.path.dirname(dst))
         fetcher.archive(dst)
 
+    def symlink(self, mirror_ref):
+        """Symlink a human readible path in our mirror to the actual
+        storage location."""
+
+        cosmetic_path = os.path.join(self.root, mirror_ref.cosmetic_path)
+        storage_path = os.path.join(self.root, mirror_ref.storage_path)
+        relative_dst = os.path.relpath(storage_path, start=os.path.dirname(cosmetic_path))
+
+        if not os.path.exists(cosmetic_path):
+            if os.path.lexists(cosmetic_path):
+                # In this case the link itself exists but it is broken: remove
+                # it and recreate it (in order to fix any symlinks broken prior
+                # to https://github.com/spack/spack/pull/13908)
+                os.unlink(cosmetic_path)
+            mkdirp(os.path.dirname(cosmetic_path))
+            symlink(relative_dst, cosmetic_path)
+
 
 #: Spack's local cache for downloaded source archives
 FETCH_CACHE: Union[spack.fetch_strategy.FsCache, llnl.util.lang.Singleton] = (

lib/spack/spack/ci.py

@@ -38,7 +38,6 @@
 import spack.paths
 import spack.repo
 import spack.spec
-import spack.stage
 import spack.util.git
 import spack.util.gpg as gpg_util
 import spack.util.spack_yaml as syaml
@@ -1108,10 +1107,9 @@ def main_script_replacements(cmd):
     if cdash_handler and cdash_handler.auth_token:
         try:
             cdash_handler.populate_buildgroup(all_job_names)
-        except (SpackError, HTTPError, URLError, TimeoutError) as err:
+        except (SpackError, HTTPError, URLError) as err:
             tty.warn(f"Problem populating buildgroup: {err}")
-    elif cdash_config:
-        # warn only if there was actually a CDash configuration.
+    else:
         tty.warn("Unable to populate buildgroup without CDash credentials")
 
     service_job_retries = {
@@ -1372,6 +1370,15 @@ def can_verify_binaries():
     return len(gpg_util.public_keys()) >= 1
 
 
+def _push_to_build_cache(spec: spack.spec.Spec, sign_binaries: bool, mirror_url: str) -> None:
+    """Unchecked version of the public API, for easier mocking"""
+    bindist.push_or_raise(
+        spec,
+        spack.mirror.Mirror.from_url(mirror_url).push_url,
+        bindist.PushOptions(force=True, unsigned=not sign_binaries),
+    )
+
+
 def push_to_build_cache(spec: spack.spec.Spec, mirror_url: str, sign_binaries: bool) -> bool:
     """Push one or more binary packages to the mirror.
 
@@ -1382,15 +1389,20 @@ def push_to_build_cache(spec: spack.spec.Spec, mirror_url: str, sign_binaries: b
         sign_binaries: If True, spack will attempt to sign binary package before pushing.
     """
     tty.debug(f"Pushing to build cache ({'signed' if sign_binaries else 'unsigned'})")
-    signing_key = bindist.select_signing_key() if sign_binaries else None
-    mirror = spack.mirror.Mirror.from_url(mirror_url)
     try:
-        with bindist.make_uploader(mirror, signing_key=signing_key) as uploader:
-            uploader.push_or_raise([spec])
+        _push_to_build_cache(spec, sign_binaries, mirror_url)
         return True
     except bindist.PushToBuildCacheError as e:
-        tty.error(f"Problem writing to {mirror_url}: {e}")
+        tty.error(str(e))
         return False
+    except Exception as e:
+        # TODO (zackgalbreath): write an adapter for boto3 exceptions so we can catch a specific
+        # exception instead of parsing str(e)...
+        msg = str(e)
+        if any(x in msg for x in ["Access Denied", "InvalidAccessKeyId"]):
+            tty.error(f"Permission problem writing to {mirror_url}: {msg}")
+            return False
+        raise
 
 
 def remove_other_mirrors(mirrors_to_keep, scope=None):
@@ -1436,6 +1448,10 @@ def copy_stage_logs_to_artifacts(job_spec: spack.spec.Spec, job_log_dir: str) ->
         job_log_dir: path into which build log should be copied
     """
     tty.debug(f"job spec: {job_spec}")
+    if not job_spec:
+        msg = f"Cannot copy stage logs: job spec ({job_spec}) is required"
+        tty.error(msg)
+        return
 
     try:
         pkg_cls = spack.repo.PATH.get_pkg_class(job_spec.name)
@@ -2067,7 +2083,7 @@ def read_broken_spec(broken_spec_url):
     """
     try:
         _, _, fs = web_util.read_from_url(broken_spec_url)
-    except web_util.SpackWebError:
+    except (URLError, web_util.SpackWebError, HTTPError):
         tty.warn(f"Unable to read broken spec from {broken_spec_url}")
         return None
 

lib/spack/spack/cmd/__init__.py

@@ -4,7 +4,6 @@
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 
 import argparse
-import importlib
 import os
 import re
 import sys
@@ -115,8 +114,8 @@ def get_module(cmd_name):
 
     try:
         # Try to import the command from the built-in directory
-        module_name = f"{__name__}.{pname}"
-        module = importlib.import_module(module_name)
+        module_name = "%s.%s" % (__name__, pname)
+        module = __import__(module_name, fromlist=[pname, SETUP_PARSER, DESCRIPTION], level=0)
         tty.debug("Imported {0} from built-in commands".format(pname))
     except ImportError:
         module = spack.extensions.get_module(cmd_name)

lib/spack/spack/cmd/buildcache.py

@@ -3,24 +3,28 @@
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 import argparse
+import copy
 import glob
+import hashlib
 import json
+import multiprocessing
+import multiprocessing.pool
 import os
 import shutil
 import sys
 import tempfile
-from typing import List, Tuple
+from typing import Dict, List, Optional, Tuple, Union
 
 import llnl.util.tty as tty
 from llnl.string import plural
-from llnl.util.lang import elide_list, stable_partition
+from llnl.util.lang import elide_list
 
 import spack.binary_distribution as bindist
 import spack.cmd
 import spack.config
-import spack.deptypes as dt
 import spack.environment as ev
 import spack.error
+import spack.hash_types as ht
 import spack.mirror
 import spack.oci.oci
 import spack.oci.opener
@@ -31,12 +35,28 @@
 import spack.store
 import spack.user_environment
 import spack.util.crypto
-import spack.util.parallel
 import spack.util.url as url_util
 import spack.util.web as web_util
 from spack import traverse
+from spack.build_environment import determine_number_of_jobs
 from spack.cmd import display_specs
 from spack.cmd.common import arguments
+from spack.oci.image import (
+    Digest,
+    ImageReference,
+    default_config,
+    default_index_tag,
+    default_manifest,
+    default_tag,
+    tag_is_spec,
+)
+from spack.oci.oci import (
+    copy_missing_layers_with_retry,
+    get_manifest_and_config_with_retry,
+    list_tags,
+    upload_blob_with_retry,
+    upload_manifest_with_retry,
+)
 from spack.spec import Spec, save_dependency_specfiles
 
 description = "create, download and install binary packages"
@@ -92,17 +112,6 @@ def setup_parser(subparser: argparse.ArgumentParser):
         "Alternatively, one can decide to build a cache for only the package or only the "
         "dependencies",
     )
-    with_or_without_build_deps = push.add_mutually_exclusive_group()
-    with_or_without_build_deps.add_argument(
-        "--with-build-dependencies",
-        action="store_true",
-        help="include build dependencies in the buildcache",
-    )
-    with_or_without_build_deps.add_argument(
-        "--without-build-dependencies",
-        action="store_true",
-        help="exclude build dependencies from the buildcache",
-    )
     push.add_argument(
         "--fail-fast",
         action="store_true",
@@ -320,6 +329,39 @@ def _format_spec(spec: Spec) -> str:
     return spec.cformat("{name}{@version}{/hash:7}")
 
 
+def _progress(i: int, total: int):
+    if total > 1:
+        digits = len(str(total))
+        return f"[{i+1:{digits}}/{total}] "
+    return ""
+
+
+class NoPool:
+    def map(self, func, args):
+        return [func(a) for a in args]
+
+    def starmap(self, func, args):
+        return [func(*a) for a in args]
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, *args):
+        pass
+
+
+MaybePool = Union[multiprocessing.pool.Pool, NoPool]
+
+
+def _make_pool() -> MaybePool:
+    """Can't use threading because it's unsafe, and can't use spawned processes because of globals.
+    That leaves only forking"""
+    if multiprocessing.get_start_method() == "fork":
+        return multiprocessing.pool.Pool(determine_number_of_jobs(parallel=True))
+    else:
+        return NoPool()
+
+
 def _skip_no_redistribute_for_public(specs):
     remaining_specs = list()
     removed_specs = list()
@@ -339,45 +381,6 @@ def _skip_no_redistribute_for_public(specs):
     return remaining_specs
 
 
-class PackagesAreNotInstalledError(spack.error.SpackError):
-    """Raised when a list of specs is not installed but picked to be packaged."""
-
-    def __init__(self, specs: List[Spec]):
-        super().__init__(
-            "Cannot push non-installed packages",
-            ", ".join(elide_list([_format_spec(s) for s in specs], 5)),
-        )
-
-
-class PackageNotInstalledError(spack.error.SpackError):
-    """Raised when a spec is not installed but picked to be packaged."""
-
-
-def _specs_to_be_packaged(
-    requested: List[Spec], things_to_install: str, build_deps: bool
-) -> List[Spec]:
-    """Collect all non-external with or without roots and dependencies"""
-    if "dependencies" not in things_to_install:
-        deptype = dt.NONE
-    elif build_deps:
-        deptype = dt.ALL
-    else:
-        deptype = dt.RUN | dt.LINK | dt.TEST
-    specs = [
-        s
-        for s in traverse.traverse_nodes(
-            requested,
-            root="package" in things_to_install,
-            deptype=deptype,
-            order="breadth",
-            key=traverse.by_dag_hash,
-        )
-        if not s.external
-    ]
-    specs.reverse()
-    return specs
-
-
 def push_fn(args):
     """create a binary package and push it to a mirror"""
     if args.spec_file:
@@ -391,8 +394,13 @@ def push_fn(args):
     else:
         roots = spack.cmd.require_active_env(cmd_name="buildcache push").concrete_roots()
 
-    mirror = args.mirror
-    assert isinstance(mirror, spack.mirror.Mirror)
+    mirror: spack.mirror.Mirror = args.mirror
+
+    # Check if this is an OCI image.
+    try:
+        target_image = spack.oci.oci.image_from_mirror(mirror)
+    except ValueError:
+        target_image = None
 
     push_url = mirror.push_url
 
@@ -403,52 +411,92 @@ def push_fn(args):
         unsigned = not (args.key or args.signed)
 
     # For OCI images, we require dependencies to be pushed for now.
-    if mirror.push_url.startswith("oci://") and not unsigned:
-        tty.warn(
-            "Code signing is currently not supported for OCI images. "
-            "Use --unsigned to silence this warning."
-        )
-        unsigned = True
+    if target_image:
+        if "dependencies" not in args.things_to_install:
+            tty.die("Dependencies must be pushed for OCI images.")
+        if not unsigned:
+            tty.warn(
+                "Code signing is currently not supported for OCI images. "
+                "Use --unsigned to silence this warning."
+            )
 
-    # Select a signing key, or None if unsigned.
-    signing_key = None if unsigned else (args.key or bindist.select_signing_key())
-
-    specs = _specs_to_be_packaged(
+    # This is a list of installed, non-external specs.
+    specs = bindist.specs_to_be_packaged(
         roots,
-        things_to_install=args.things_to_install,
-        build_deps=args.with_build_dependencies or not args.without_build_dependencies,
+        root="package" in args.things_to_install,
+        dependencies="dependencies" in args.things_to_install,
     )
-
     if not args.private:
         specs = _skip_no_redistribute_for_public(specs)
 
+    # When pushing multiple specs, print the url once ahead of time, as well as how
+    # many specs are being pushed.
     if len(specs) > 1:
         tty.info(f"Selected {len(specs)} specs to push to {push_url}")
 
-    # Pushing not installed specs is an error. Either fail fast or populate the error list and
-    # push installed package in best effort mode.
-    failed: List[Tuple[Spec, BaseException]] = []
-    with spack.store.STORE.db.read_transaction():
-        if any(not s.installed for s in specs):
-            specs, not_installed = stable_partition(specs, lambda s: s.installed)
-            if args.fail_fast:
-                raise PackagesAreNotInstalledError(not_installed)
-            else:
-                failed.extend(
-                    (s, PackageNotInstalledError("package not installed")) for s in not_installed
+    failed = []
+
+    # TODO: unify this logic in the future.
+    if target_image:
+        base_image = ImageReference.from_string(args.base_image) if args.base_image else None
+        with tempfile.TemporaryDirectory(
+            dir=spack.stage.get_stage_root()
+        ) as tmpdir, _make_pool() as pool:
+            skipped, base_images, checksums = _push_oci(
+                target_image=target_image,
+                base_image=base_image,
+                installed_specs_with_deps=specs,
+                force=args.force,
+                tmpdir=tmpdir,
+                pool=pool,
+            )
+
+            # Apart from creating manifests for each individual spec, we allow users to create a
+            # separate image tag for all root specs and their runtime dependencies.
+            if args.tag:
+                tagged_image = target_image.with_tag(args.tag)
+                # _push_oci may not populate base_images if binaries were already in the registry
+                for spec in roots:
+                    _update_base_images(
+                        base_image=base_image,
+                        target_image=target_image,
+                        spec=spec,
+                        base_image_cache=base_images,
+                    )
+                _put_manifest(base_images, checksums, tagged_image, tmpdir, None, None, *roots)
+                tty.info(f"Tagged {tagged_image}")
+
+    else:
+        skipped = []
+
+        for i, spec in enumerate(specs):
+            try:
+                bindist.push_or_raise(
+                    spec,
+                    push_url,
+                    bindist.PushOptions(
+                        force=args.force,
+                        unsigned=unsigned,
+                        key=args.key,
+                        regenerate_index=args.update_index,
+                    ),
                 )
 
-    with bindist.make_uploader(
-        mirror=mirror,
-        force=args.force,
-        update_index=args.update_index,
-        signing_key=signing_key,
-        base_image=args.base_image,
-    ) as uploader:
-        skipped, upload_errors = uploader.push(specs=specs)
-        failed.extend(upload_errors)
-        if not upload_errors and args.tag:
-            uploader.tag(args.tag, roots)
+                msg = f"{_progress(i, len(specs))}Pushed {_format_spec(spec)}"
+                if len(specs) == 1:
+                    msg += f" to {push_url}"
+                tty.info(msg)
+
+            except bindist.NoOverwriteException:
+                skipped.append(_format_spec(spec))
+
+            # Catch any other exception unless the fail fast option is set
+            except Exception as e:
+                if args.fail_fast or isinstance(
+                    e, (bindist.PickKeyException, bindist.NoKeyException)
+                ):
+                    raise
+                failed.append((_format_spec(spec), e))
 
     if skipped:
         if len(specs) == 1:
@@ -471,16 +519,390 @@ def push_fn(args):
         raise spack.error.SpackError(
             f"The following {len(failed)} errors occurred while pushing specs to the buildcache",
             "\n".join(
-                elide_list(
-                    [
-                        f"    {_format_spec(spec)}: {e.__class__.__name__}: {e}"
-                        for spec, e in failed
-                    ],
-                    5,
-                )
+                elide_list([f"    {spec}: {e.__class__.__name__}: {e}" for spec, e in failed], 5)
             ),
         )
 
+    # Update the index if requested
+    # TODO: remove update index logic out of bindist; should be once after all specs are pushed
+    # not once per spec.
+    if target_image and len(skipped) < len(specs) and args.update_index:
+        with tempfile.TemporaryDirectory(
+            dir=spack.stage.get_stage_root()
+        ) as tmpdir, _make_pool() as pool:
+            _update_index_oci(target_image, tmpdir, pool)
+
+
+def _get_spack_binary_blob(image_ref: ImageReference) -> Optional[spack.oci.oci.Blob]:
+    """Get the spack tarball layer digests and size if it exists"""
+    try:
+        manifest, config = get_manifest_and_config_with_retry(image_ref)
+
+        return spack.oci.oci.Blob(
+            compressed_digest=Digest.from_string(manifest["layers"][-1]["digest"]),
+            uncompressed_digest=Digest.from_string(config["rootfs"]["diff_ids"][-1]),
+            size=manifest["layers"][-1]["size"],
+        )
+    except Exception:
+        return None
+
+
+def _push_single_spack_binary_blob(image_ref: ImageReference, spec: spack.spec.Spec, tmpdir: str):
+    filename = os.path.join(tmpdir, f"{spec.dag_hash()}.tar.gz")
+
+    # Create an oci.image.layer aka tarball of the package
+    compressed_tarfile_checksum, tarfile_checksum = spack.oci.oci.create_tarball(spec, filename)
+
+    blob = spack.oci.oci.Blob(
+        Digest.from_sha256(compressed_tarfile_checksum),
+        Digest.from_sha256(tarfile_checksum),
+        os.path.getsize(filename),
+    )
+
+    # Upload the blob
+    upload_blob_with_retry(image_ref, file=filename, digest=blob.compressed_digest)
+
+    # delete the file
+    os.unlink(filename)
+
+    return blob
+
+
+def _retrieve_env_dict_from_config(config: dict) -> dict:
+    """Retrieve the environment variables from the image config file.
+    Sets a default value for PATH if it is not present.
+
+    Args:
+        config (dict): The image config file.
+
+    Returns:
+        dict: The environment variables.
+    """
+    env = {"PATH": "/bin:/usr/bin"}
+
+    if "Env" in config.get("config", {}):
+        for entry in config["config"]["Env"]:
+            key, value = entry.split("=", 1)
+            env[key] = value
+    return env
+
+
+def _archspec_to_gooarch(spec: spack.spec.Spec) -> str:
+    name = spec.target.family.name
+    name_map = {"aarch64": "arm64", "x86_64": "amd64"}
+    return name_map.get(name, name)
+
+
+def _put_manifest(
+    base_images: Dict[str, Tuple[dict, dict]],
+    checksums: Dict[str, spack.oci.oci.Blob],
+    image_ref: ImageReference,
+    tmpdir: str,
+    extra_config: Optional[dict],
+    annotations: Optional[dict],
+    *specs: spack.spec.Spec,
+):
+    architecture = _archspec_to_gooarch(specs[0])
+
+    dependencies = list(
+        reversed(
+            list(
+                s
+                for s in traverse.traverse_nodes(
+                    specs, order="topo", deptype=("link", "run"), root=True
+                )
+                if not s.external
+            )
+        )
+    )
+
+    base_manifest, base_config = base_images[architecture]
+    env = _retrieve_env_dict_from_config(base_config)
+
+    # If the base image uses `vnd.docker.distribution.manifest.v2+json`, then we use that too.
+    # This is because Singularity / Apptainer is very strict about not mixing them.
+    base_manifest_mediaType = base_manifest.get(
+        "mediaType", "application/vnd.oci.image.manifest.v1+json"
+    )
+    use_docker_format = (
+        base_manifest_mediaType == "application/vnd.docker.distribution.manifest.v2+json"
+    )
+
+    spack.user_environment.environment_modifications_for_specs(*specs).apply_modifications(env)
+
+    # Create an oci.image.config file
+    config = copy.deepcopy(base_config)
+
+    # Add the diff ids of the dependencies
+    for s in dependencies:
+        config["rootfs"]["diff_ids"].append(str(checksums[s.dag_hash()].uncompressed_digest))
+
+    # Set the environment variables
+    config["config"]["Env"] = [f"{k}={v}" for k, v in env.items()]
+
+    if extra_config:
+        # From the OCI v1.0 spec:
+        # > Any extra fields in the Image JSON struct are considered implementation
+        # > specific and MUST be ignored by any implementations which are unable to
+        # > interpret them.
+        config.update(extra_config)
+
+    config_file = os.path.join(tmpdir, f"{specs[0].dag_hash()}.config.json")
+
+    with open(config_file, "w") as f:
+        json.dump(config, f, separators=(",", ":"))
+
+    config_file_checksum = Digest.from_sha256(
+        spack.util.crypto.checksum(hashlib.sha256, config_file)
+    )
+
+    # Upload the config file
+    upload_blob_with_retry(image_ref, file=config_file, digest=config_file_checksum)
+
+    manifest = {
+        "mediaType": base_manifest_mediaType,
+        "schemaVersion": 2,
+        "config": {
+            "mediaType": base_manifest["config"]["mediaType"],
+            "digest": str(config_file_checksum),
+            "size": os.path.getsize(config_file),
+        },
+        "layers": [
+            *(layer for layer in base_manifest["layers"]),
+            *(
+                {
+                    "mediaType": (
+                        "application/vnd.docker.image.rootfs.diff.tar.gzip"
+                        if use_docker_format
+                        else "application/vnd.oci.image.layer.v1.tar+gzip"
+                    ),
+                    "digest": str(checksums[s.dag_hash()].compressed_digest),
+                    "size": checksums[s.dag_hash()].size,
+                }
+                for s in dependencies
+            ),
+        ],
+    }
+
+    if not use_docker_format and annotations:
+        manifest["annotations"] = annotations
+
+    # Finally upload the manifest
+    upload_manifest_with_retry(image_ref, manifest=manifest)
+
+    # delete the config file
+    os.unlink(config_file)
+
+
+def _update_base_images(
+    *,
+    base_image: Optional[ImageReference],
+    target_image: ImageReference,
+    spec: spack.spec.Spec,
+    base_image_cache: Dict[str, Tuple[dict, dict]],
+):
+    """For a given spec and base image, copy the missing layers of the base image with matching
+    arch to the registry of the target image. If no base image is specified, create a dummy
+    manifest and config file."""
+    architecture = _archspec_to_gooarch(spec)
+    if architecture in base_image_cache:
+        return
+    if base_image is None:
+        base_image_cache[architecture] = (
+            default_manifest(),
+            default_config(architecture, "linux"),
+        )
+    else:
+        base_image_cache[architecture] = copy_missing_layers_with_retry(
+            base_image, target_image, architecture
+        )
+
+
+def _push_oci(
+    *,
+    target_image: ImageReference,
+    base_image: Optional[ImageReference],
+    installed_specs_with_deps: List[Spec],
+    tmpdir: str,
+    pool: MaybePool,
+    force: bool = False,
+) -> Tuple[List[str], Dict[str, Tuple[dict, dict]], Dict[str, spack.oci.oci.Blob]]:
+    """Push specs to an OCI registry
+
+    Args:
+        image_ref: The target OCI image
+        base_image: Optional base image, which will be copied to the target registry.
+        installed_specs_with_deps: The installed specs to push, excluding externals,
+            including deps, ordered from roots to leaves.
+        force: Whether to overwrite existing layers and manifests in the buildcache.
+
+    Returns:
+        A tuple consisting of the list of skipped specs already in the build cache,
+        a dictionary mapping architectures to base image manifests and configs,
+        and a dictionary mapping each spec's dag hash to a blob.
+    """
+
+    # Reverse the order
+    installed_specs_with_deps = list(reversed(installed_specs_with_deps))
+
+    # Spec dag hash -> blob
+    checksums: Dict[str, spack.oci.oci.Blob] = {}
+
+    # arch -> (manifest, config)
+    base_images: Dict[str, Tuple[dict, dict]] = {}
+
+    # Specs not uploaded because they already exist
+    skipped = []
+
+    if not force:
+        tty.info("Checking for existing specs in the buildcache")
+        to_be_uploaded = []
+
+        tags_to_check = (target_image.with_tag(default_tag(s)) for s in installed_specs_with_deps)
+        available_blobs = pool.map(_get_spack_binary_blob, tags_to_check)
+
+        for spec, maybe_blob in zip(installed_specs_with_deps, available_blobs):
+            if maybe_blob is not None:
+                checksums[spec.dag_hash()] = maybe_blob
+                skipped.append(_format_spec(spec))
+            else:
+                to_be_uploaded.append(spec)
+    else:
+        to_be_uploaded = installed_specs_with_deps
+
+    if not to_be_uploaded:
+        return skipped, base_images, checksums
+
+    tty.info(
+        f"{len(to_be_uploaded)} specs need to be pushed to "
+        f"{target_image.domain}/{target_image.name}"
+    )
+
+    # Upload blobs
+    new_blobs = pool.starmap(
+        _push_single_spack_binary_blob, ((target_image, spec, tmpdir) for spec in to_be_uploaded)
+    )
+
+    # And update the spec to blob mapping
+    for spec, blob in zip(to_be_uploaded, new_blobs):
+        checksums[spec.dag_hash()] = blob
+
+    # Copy base images if necessary
+    for spec in to_be_uploaded:
+        _update_base_images(
+            base_image=base_image,
+            target_image=target_image,
+            spec=spec,
+            base_image_cache=base_images,
+        )
+
+    def extra_config(spec: Spec):
+        spec_dict = spec.to_dict(hash=ht.dag_hash)
+        spec_dict["buildcache_layout_version"] = 1
+        spec_dict["binary_cache_checksum"] = {
+            "hash_algorithm": "sha256",
+            "hash": checksums[spec.dag_hash()].compressed_digest.digest,
+        }
+        return spec_dict
+
+    # Upload manifests
+    tty.info("Uploading manifests")
+    pool.starmap(
+        _put_manifest,
+        (
+            (
+                base_images,
+                checksums,
+                target_image.with_tag(default_tag(spec)),
+                tmpdir,
+                extra_config(spec),
+                {"org.opencontainers.image.description": spec.format()},
+                spec,
+            )
+            for spec in to_be_uploaded
+        ),
+    )
+
+    # Print the image names of the top-level specs
+    for spec in to_be_uploaded:
+        tty.info(f"Pushed {_format_spec(spec)} to {target_image.with_tag(default_tag(spec))}")
+
+    return skipped, base_images, checksums
+
+
+def _config_from_tag(image_ref: ImageReference, tag: str) -> Optional[dict]:
+    # Don't allow recursion here, since Spack itself always uploads
+    # vnd.oci.image.manifest.v1+json, not vnd.oci.image.index.v1+json
+    _, config = get_manifest_and_config_with_retry(image_ref.with_tag(tag), tag, recurse=0)
+
+    # Do very basic validation: if "spec" is a key in the config, it
+    # must be a Spec object too.
+    return config if "spec" in config else None
+
+
+def _update_index_oci(image_ref: ImageReference, tmpdir: str, pool: MaybePool) -> None:
+    tags = list_tags(image_ref)
+
+    # Fetch all image config files in parallel
+    spec_dicts = pool.starmap(
+        _config_from_tag, ((image_ref, tag) for tag in tags if tag_is_spec(tag))
+    )
+
+    # Populate the database
+    db_root_dir = os.path.join(tmpdir, "db_root")
+    db = bindist.BuildCacheDatabase(db_root_dir)
+
+    for spec_dict in spec_dicts:
+        spec = Spec.from_dict(spec_dict)
+        db.add(spec, directory_layout=None)
+        db.mark(spec, "in_buildcache", True)
+
+    # Create the index.json file
+    index_json_path = os.path.join(tmpdir, "index.json")
+    with open(index_json_path, "w") as f:
+        db._write_to_file(f)
+
+    # Create an empty config.json file
+    empty_config_json_path = os.path.join(tmpdir, "config.json")
+    with open(empty_config_json_path, "wb") as f:
+        f.write(b"{}")
+
+    # Upload the index.json file
+    index_shasum = Digest.from_sha256(spack.util.crypto.checksum(hashlib.sha256, index_json_path))
+    upload_blob_with_retry(image_ref, file=index_json_path, digest=index_shasum)
+
+    # Upload the config.json file
+    empty_config_digest = Digest.from_sha256(
+        spack.util.crypto.checksum(hashlib.sha256, empty_config_json_path)
+    )
+    upload_blob_with_retry(image_ref, file=empty_config_json_path, digest=empty_config_digest)
+
+    # Push a manifest file that references the index.json file as a layer
+    # Notice that we push this as if it is an image, which it of course is not.
+    # When the ORAS spec becomes official, we can use that instead of a fake image.
+    # For now we just use the OCI image spec, so that we don't run into issues with
+    # automatic garbage collection of blobs that are not referenced by any image manifest.
+    oci_manifest = {
+        "mediaType": "application/vnd.oci.image.manifest.v1+json",
+        "schemaVersion": 2,
+        # Config is just an empty {} file for now, and irrelevant
+        "config": {
+            "mediaType": "application/vnd.oci.image.config.v1+json",
+            "digest": str(empty_config_digest),
+            "size": os.path.getsize(empty_config_json_path),
+        },
+        # The buildcache index is the only layer, and is not a tarball, we lie here.
+        "layers": [
+            {
+                "mediaType": "application/vnd.oci.image.layer.v1.tar+gzip",
+                "digest": str(index_shasum),
+                "size": os.path.getsize(index_json_path),
+            }
+        ],
+    }
+
+    upload_manifest_with_retry(image_ref.with_tag(default_index_tag), oci_manifest)
+
 
 def install_fn(args):
     """install from a binary package"""
@@ -760,15 +1182,14 @@ def update_index(mirror: spack.mirror.Mirror, update_keys=False):
     if image_ref:
         with tempfile.TemporaryDirectory(
             dir=spack.stage.get_stage_root()
-        ) as tmpdir, spack.util.parallel.make_concurrent_executor() as executor:
-            bindist._oci_update_index(image_ref, tmpdir, executor)
+        ) as tmpdir, _make_pool() as pool:
+            _update_index_oci(image_ref, tmpdir, pool)
         return
 
     # Otherwise, assume a normal mirror.
     url = mirror.push_url
 
-    with tempfile.TemporaryDirectory(dir=spack.stage.get_stage_root()) as tmpdir:
-        bindist._url_generate_package_index(url, tmpdir)
+    bindist.generate_package_index(url_util.join(url, bindist.build_cache_relative_path()))
 
     if update_keys:
         keys_url = url_util.join(
@@ -776,8 +1197,7 @@ def update_index(mirror: spack.mirror.Mirror, update_keys=False):
         )
 
         try:
-            with tempfile.TemporaryDirectory(dir=spack.stage.get_stage_root()) as tmpdir:
-                bindist.generate_key_index(keys_url, tmpdir)
+            bindist.generate_key_index(keys_url)
         except bindist.CannotListKeys as e:
             # Do not error out if listing keys went wrong. This usually means that the _gpg path
             # does not exist. TODO: distinguish between this and other errors.

lib/spack/spack/cmd/compiler.py

@@ -50,7 +50,6 @@ def setup_parser(subparser):
         default=lambda: spack.config.default_modify_scope("compilers"),
         help="configuration scope to modify",
     )
-    arguments.add_common_arguments(find_parser, ["jobs"])
 
     # Remove
     remove_parser = sp.add_parser("remove", aliases=["rm"], help="remove compiler by spec")
@@ -79,21 +78,25 @@ def setup_parser(subparser):
 def compiler_find(args):
     """Search either $PATH or a list of paths OR MODULES for compilers and
     add them to Spack's configuration.
+
     """
+    # None signals spack.compiler.find_compilers to use its default logic
     paths = args.add_paths or None
-    new_compilers = spack.compilers.find_compilers(
-        path_hints=paths,
-        scope=args.scope,
-        mixed_toolchain=args.mixed_toolchain,
-        max_workers=args.jobs,
+
+    # Below scope=None because we want new compilers that don't appear
+    # in any other configuration.
+    new_compilers = spack.compilers.find_new_compilers(
+        paths, scope=None, mixed_toolchain=args.mixed_toolchain
     )
     if new_compilers:
+        spack.compilers.add_compilers_to_config(new_compilers, scope=args.scope)
         n = len(new_compilers)
         s = "s" if n > 1 else ""
-        filename = spack.config.CONFIG.get_config_filename(args.scope, "compilers")
-        tty.msg(f"Added {n:d} new compiler{s} to {filename}")
-        compiler_strs = sorted(f"{c.spec.name}@{c.spec.version}" for c in new_compilers)
-        colify(reversed(compiler_strs), indent=4)
+
+        config = spack.config.CONFIG
+        filename = config.get_config_filename(args.scope, "compilers")
+        tty.msg("Added %d new compiler%s to %s" % (n, s, filename))
+        colify(reversed(sorted(c.spec.display_str for c in new_compilers)), indent=4)
     else:
         tty.msg("Found no new compilers")
     tty.msg("Compilers are defined in the following files:")

lib/spack/spack/cmd/create.py

@@ -6,7 +6,6 @@
 import re
 import sys
 import urllib.parse
-from typing import List
 
 import llnl.util.tty as tty
 from llnl.util.filesystem import mkdirp
@@ -15,15 +14,9 @@
 import spack.stage
 import spack.util.web
 from spack.spec import Spec
-from spack.url import (
-    UndetectableNameError,
-    UndetectableVersionError,
-    find_versions_of_archive,
-    parse_name,
-    parse_version,
-)
+from spack.url import UndetectableNameError, UndetectableVersionError, parse_name, parse_version
 from spack.util.editor import editor
-from spack.util.executable import which
+from spack.util.executable import ProcessError, which
 from spack.util.format import get_version_lines
 from spack.util.naming import mod_to_class, simplify_name, valid_fully_qualified_module_name
 
@@ -96,20 +89,14 @@ class BundlePackageTemplate:
     url_def = "    # There is no URL since there is no code to download."
     body_def = "    # There is no need for install() since there is no code."
 
-    def __init__(self, name: str, versions, languages: List[str]):
+    def __init__(self, name, versions):
         self.name = name
         self.class_name = mod_to_class(name)
         self.versions = versions
-        self.languages = languages
 
     def write(self, pkg_path):
         """Writes the new package file."""
 
-        all_deps = [f'    depends_on("{lang}", type="build")' for lang in self.languages]
-        if all_deps and self.dependencies:
-            all_deps.append("")
-        all_deps.append(self.dependencies)
-
         # Write out a template for the file
         with open(pkg_path, "w") as pkg_file:
             pkg_file.write(
@@ -119,7 +106,7 @@ def write(self, pkg_path):
                     base_class_name=self.base_class_name,
                     url_def=self.url_def,
                     versions=self.versions,
-                    dependencies="\n".join(all_deps),
+                    dependencies=self.dependencies,
                     body_def=self.body_def,
                 )
             )
@@ -138,8 +125,8 @@ def install(self, spec, prefix):
 
     url_line = '    url = "{url}"'
 
-    def __init__(self, name, url, versions, languages: List[str]):
-        super().__init__(name, versions, languages)
+    def __init__(self, name, url, versions):
+        super().__init__(name, versions)
 
         self.url_def = self.url_line.format(url=url)
 
@@ -227,13 +214,13 @@ def luarocks_args(self):
         args = []
         return args"""
 
-    def __init__(self, name, url, versions, languages: List[str]):
+    def __init__(self, name, url, *args, **kwargs):
         # If the user provided `--name lua-lpeg`, don't rename it lua-lua-lpeg
         if not name.startswith("lua-"):
             # Make it more obvious that we are renaming the package
             tty.msg("Changing package name from {0} to lua-{0}".format(name))
             name = "lua-{0}".format(name)
-        super().__init__(name, url, versions, languages)
+        super().__init__(name, url, *args, **kwargs)
 
 
 class MesonPackageTemplate(PackageTemplate):
@@ -334,14 +321,14 @@ class RacketPackageTemplate(PackageTemplate):
     # subdirectory = None
     """
 
-    def __init__(self, name, url, versions, languages: List[str]):
+    def __init__(self, name, url, *args, **kwargs):
         # If the user provided `--name rkt-scribble`, don't rename it rkt-rkt-scribble
         if not name.startswith("rkt-"):
             # Make it more obvious that we are renaming the package
             tty.msg("Changing package name from {0} to rkt-{0}".format(name))
             name = "rkt-{0}".format(name)
         self.body_def = self.body_def.format(name[4:])
-        super().__init__(name, url, versions, languages)
+        super().__init__(name, url, *args, **kwargs)
 
 
 class PythonPackageTemplate(PackageTemplate):
@@ -374,7 +361,7 @@ def config_settings(self, spec, prefix):
         settings = {}
         return settings"""
 
-    def __init__(self, name, url, versions, languages: List[str]):
+    def __init__(self, name, url, *args, **kwargs):
         # If the user provided `--name py-numpy`, don't rename it py-py-numpy
         if not name.startswith("py-"):
             # Make it more obvious that we are renaming the package
@@ -428,7 +415,7 @@ def __init__(self, name, url, versions, languages: List[str]):
                 + self.url_line
             )
 
-        super().__init__(name, url, versions, languages)
+        super().__init__(name, url, *args, **kwargs)
 
 
 class RPackageTemplate(PackageTemplate):
@@ -447,7 +434,7 @@ def configure_args(self):
         args = []
         return args"""
 
-    def __init__(self, name, url, versions, languages: List[str]):
+    def __init__(self, name, url, *args, **kwargs):
         # If the user provided `--name r-rcpp`, don't rename it r-r-rcpp
         if not name.startswith("r-"):
             # Make it more obvious that we are renaming the package
@@ -467,7 +454,7 @@ def __init__(self, name, url, versions, languages: List[str]):
         if bioc:
             self.url_line = '    url = "{0}"\n' '    bioc = "{1}"'.format(url, r_name)
 
-        super().__init__(name, url, versions, languages)
+        super().__init__(name, url, *args, **kwargs)
 
 
 class PerlmakePackageTemplate(PackageTemplate):
@@ -487,14 +474,14 @@ def configure_args(self):
         args = []
         return args"""
 
-    def __init__(self, name, url, versions, languages: List[str]):
+    def __init__(self, name, *args, **kwargs):
         # If the user provided `--name perl-cpp`, don't rename it perl-perl-cpp
         if not name.startswith("perl-"):
             # Make it more obvious that we are renaming the package
             tty.msg("Changing package name from {0} to perl-{0}".format(name))
             name = "perl-{0}".format(name)
 
-        super().__init__(name, url, versions, languages)
+        super().__init__(name, *args, **kwargs)
 
 
 class PerlbuildPackageTemplate(PerlmakePackageTemplate):
@@ -519,7 +506,7 @@ class OctavePackageTemplate(PackageTemplate):
     # FIXME: Add additional dependencies if required.
     # depends_on("octave-foo", type=("build", "run"))"""
 
-    def __init__(self, name, url, versions, languages: List[str]):
+    def __init__(self, name, *args, **kwargs):
         # If the user provided `--name octave-splines`, don't rename it
         # octave-octave-splines
         if not name.startswith("octave-"):
@@ -527,7 +514,7 @@ def __init__(self, name, url, versions, languages: List[str]):
             tty.msg("Changing package name from {0} to octave-{0}".format(name))
             name = "octave-{0}".format(name)
 
-        super().__init__(name, url, versions, languages)
+        super().__init__(name, *args, **kwargs)
 
 
 class RubyPackageTemplate(PackageTemplate):
@@ -547,7 +534,7 @@ def build(self, spec, prefix):
         # FIXME: If not needed delete this function
         pass"""
 
-    def __init__(self, name, url, versions, languages: List[str]):
+    def __init__(self, name, *args, **kwargs):
         # If the user provided `--name ruby-numpy`, don't rename it
         # ruby-ruby-numpy
         if not name.startswith("ruby-"):
@@ -555,7 +542,7 @@ def __init__(self, name, url, versions, languages: List[str]):
             tty.msg("Changing package name from {0} to ruby-{0}".format(name))
             name = "ruby-{0}".format(name)
 
-        super().__init__(name, url, versions, languages)
+        super().__init__(name, *args, **kwargs)
 
 
 class MakefilePackageTemplate(PackageTemplate):
@@ -593,14 +580,14 @@ def configure_args(self, spec, prefix):
         args = []
         return args"""
 
-    def __init__(self, name, url, versions, languages: List[str]):
+    def __init__(self, name, *args, **kwargs):
         # If the user provided `--name py-pyqt4`, don't rename it py-py-pyqt4
         if not name.startswith("py-"):
             # Make it more obvious that we are renaming the package
             tty.msg("Changing package name from {0} to py-{0}".format(name))
             name = "py-{0}".format(name)
 
-        super().__init__(name, url, versions, languages)
+        super().__init__(name, *args, **kwargs)
 
 
 templates = {
@@ -671,48 +658,8 @@ def setup_parser(subparser):
     )
 
 
-#: C file extensions
-C_EXT = {".c"}
-
-#: C++ file extensions
-CXX_EXT = {
-    ".C",
-    ".c++",
-    ".cc",
-    ".ccm",
-    ".cpp",
-    ".CPP",
-    ".cxx",
-    ".h++",
-    ".hh",
-    ".hpp",
-    ".hxx",
-    ".inl",
-    ".ipp",
-    ".ixx",
-    ".tcc",
-    ".tpp",
-}
-
-#: Fortran file extensions
-FORTRAN_EXT = {
-    ".f77",
-    ".F77",
-    ".f90",
-    ".F90",
-    ".f95",
-    ".F95",
-    ".f",
-    ".F",
-    ".for",
-    ".FOR",
-    ".ftn",
-    ".FTN",
-}
-
-
-class BuildSystemAndLanguageGuesser:
-    """An instance of BuildSystemAndLanguageGuesser provides a callable object to be used
+class BuildSystemGuesser:
+    """An instance of BuildSystemGuesser provides a callable object to be used
     during ``spack create``. By passing this object to ``spack checksum``, we
     can take a peek at the fetched tarball and discern the build system it uses
     """
@@ -720,119 +667,81 @@ class BuildSystemAndLanguageGuesser:
     def __init__(self):
         """Sets the default build system."""
         self.build_system = "generic"
-        self._c = False
-        self._cxx = False
-        self._fortran = False
 
-        # List of files in the archive ordered by their depth in the directory tree.
-        self._file_entries: List[str] = []
-
-    def __call__(self, archive: str, url: str) -> None:
+    def __call__(self, stage, url):
         """Try to guess the type of build system used by a project based on
         the contents of its archive or the URL it was downloaded from."""
 
+        if url is not None:
+            # Most octave extensions are hosted on Octave-Forge:
+            #     https://octave.sourceforge.net/index.html
+            # They all have the same base URL.
+            if "downloads.sourceforge.net/octave/" in url:
+                self.build_system = "octave"
+                return
+            if url.endswith(".gem"):
+                self.build_system = "ruby"
+                return
+            if url.endswith(".whl") or ".whl#" in url:
+                self.build_system = "python"
+                return
+            if url.endswith(".rock"):
+                self.build_system = "lua"
+                return
+
+        # A list of clues that give us an idea of the build system a package
+        # uses. If the regular expression matches a file contained in the
+        # archive, the corresponding build system is assumed.
+        # NOTE: Order is important here. If a package supports multiple
+        # build systems, we choose the first match in this list.
+        clues = [
+            (r"/CMakeLists\.txt$", "cmake"),
+            (r"/NAMESPACE$", "r"),
+            (r"/Cargo\.toml$", "cargo"),
+            (r"/go\.mod$", "go"),
+            (r"/configure$", "autotools"),
+            (r"/configure\.(in|ac)$", "autoreconf"),
+            (r"/Makefile\.am$", "autoreconf"),
+            (r"/pom\.xml$", "maven"),
+            (r"/SConstruct$", "scons"),
+            (r"/waf$", "waf"),
+            (r"/pyproject.toml", "python"),
+            (r"/setup\.(py|cfg)$", "python"),
+            (r"/WORKSPACE$", "bazel"),
+            (r"/Build\.PL$", "perlbuild"),
+            (r"/Makefile\.PL$", "perlmake"),
+            (r"/.*\.gemspec$", "ruby"),
+            (r"/Rakefile$", "ruby"),
+            (r"/setup\.rb$", "ruby"),
+            (r"/.*\.pro$", "qmake"),
+            (r"/.*\.rockspec$", "lua"),
+            (r"/(GNU)?[Mm]akefile$", "makefile"),
+            (r"/DESCRIPTION$", "octave"),
+            (r"/meson\.build$", "meson"),
+            (r"/configure\.py$", "sip"),
+        ]
+
         # Peek inside the compressed file.
-        if archive.endswith(".zip") or ".zip#" in archive:
+        if stage.archive_file.endswith(".zip") or ".zip#" in stage.archive_file:
             try:
                 unzip = which("unzip")
-                assert unzip is not None
-                output = unzip("-lq", archive, output=str)
-            except Exception:
+                output = unzip("-lq", stage.archive_file, output=str)
+            except ProcessError:
                 output = ""
         else:
             try:
                 tar = which("tar")
-                assert tar is not None
-                output = tar("tf", archive, output=str)
-            except Exception:
+                output = tar("--exclude=*/*/*", "-tf", stage.archive_file, output=str)
+            except ProcessError:
                 output = ""
-        self._file_entries[:] = output.splitlines()
+        lines = output.splitlines()
 
-        # Files closest to the root should be considered first when determining build system.
-        self._file_entries.sort(key=lambda p: p.count("/"))
-
-        self._determine_build_system(url)
-        self._determine_language()
-
-    def _determine_build_system(self, url: str) -> None:
-        # Most octave extensions are hosted on Octave-Forge:
-        #     https://octave.sourceforge.net/index.html
-        # They all have the same base URL.
-        if "downloads.sourceforge.net/octave/" in url:
-            self.build_system = "octave"
-        elif url.endswith(".gem"):
-            self.build_system = "ruby"
-        elif url.endswith(".whl") or ".whl#" in url:
-            self.build_system = "python"
-        elif url.endswith(".rock"):
-            self.build_system = "lua"
-        elif self._file_entries:
-            # A list of clues that give us an idea of the build system a package
-            # uses. If the regular expression matches a file contained in the
-            # archive, the corresponding build system is assumed.
-            # NOTE: Order is important here. If a package supports multiple
-            # build systems, we choose the first match in this list.
-            clues = [
-                (re.compile(pattern), build_system)
-                for pattern, build_system in (
-                    (r"/CMakeLists\.txt$", "cmake"),
-                    (r"/NAMESPACE$", "r"),
-                    (r"/Cargo\.toml$", "cargo"),
-                    (r"/go\.mod$", "go"),
-                    (r"/configure$", "autotools"),
-                    (r"/configure\.(in|ac)$", "autoreconf"),
-                    (r"/Makefile\.am$", "autoreconf"),
-                    (r"/pom\.xml$", "maven"),
-                    (r"/SConstruct$", "scons"),
-                    (r"/waf$", "waf"),
-                    (r"/pyproject.toml", "python"),
-                    (r"/setup\.(py|cfg)$", "python"),
-                    (r"/WORKSPACE$", "bazel"),
-                    (r"/Build\.PL$", "perlbuild"),
-                    (r"/Makefile\.PL$", "perlmake"),
-                    (r"/.*\.gemspec$", "ruby"),
-                    (r"/Rakefile$", "ruby"),
-                    (r"/setup\.rb$", "ruby"),
-                    (r"/.*\.pro$", "qmake"),
-                    (r"/.*\.rockspec$", "lua"),
-                    (r"/(GNU)?[Mm]akefile$", "makefile"),
-                    (r"/DESCRIPTION$", "octave"),
-                    (r"/meson\.build$", "meson"),
-                    (r"/configure\.py$", "sip"),
-                )
-            ]
-
-            # Determine the build system based on the files contained in the archive.
-            for file in self._file_entries:
-                for pattern, build_system in clues:
-                    if pattern.search(file):
-                        self.build_system = build_system
-                        return
-
-    def _determine_language(self):
-        for entry in self._file_entries:
-            _, ext = os.path.splitext(entry)
-
-            if not self._c and ext in C_EXT:
-                self._c = True
-            elif not self._cxx and ext in CXX_EXT:
-                self._cxx = True
-            elif not self._fortran and ext in FORTRAN_EXT:
-                self._fortran = True
-
-            if self._c and self._cxx and self._fortran:
-                return
-
-    @property
-    def languages(self) -> List[str]:
-        langs: List[str] = []
-        if self._c:
-            langs.append("c")
-        if self._cxx:
-            langs.append("cxx")
-        if self._fortran:
-            langs.append("fortran")
-        return langs
+        # Determine the build system based on the files contained
+        # in the archive.
+        for pattern, bs in clues:
+            if any(re.search(pattern, line) for line in lines):
+                self.build_system = bs
+                break
 
 
 def get_name(name, url):
@@ -902,7 +811,7 @@ def get_url(url):
 def get_versions(args, name):
     """Returns a list of versions and hashes for a package.
 
-    Also returns a BuildSystemAndLanguageGuesser object.
+    Also returns a BuildSystemGuesser object.
 
     Returns default values if no URL is provided.
 
@@ -911,7 +820,7 @@ def get_versions(args, name):
         name (str): The name of the package
 
     Returns:
-        tuple: versions and hashes, and a BuildSystemAndLanguageGuesser object
+        tuple: versions and hashes, and a BuildSystemGuesser object
     """
 
     # Default version with hash
@@ -925,7 +834,7 @@ def get_versions(args, name):
     # version("1.2.4")"""
 
     # Default guesser
-    guesser = BuildSystemAndLanguageGuesser()
+    guesser = BuildSystemGuesser()
 
     valid_url = True
     try:
@@ -938,7 +847,7 @@ def get_versions(args, name):
     if args.url is not None and args.template != "bundle" and valid_url:
         # Find available versions
         try:
-            url_dict = find_versions_of_archive(args.url)
+            url_dict = spack.url.find_versions_of_archive(args.url)
             if len(url_dict) > 1 and not args.batch and sys.stdin.isatty():
                 url_dict_filtered = spack.stage.interactive_version_filter(url_dict)
                 if url_dict_filtered is None:
@@ -965,7 +874,7 @@ def get_versions(args, name):
     return versions, guesser
 
 
-def get_build_system(template: str, url: str, guesser: BuildSystemAndLanguageGuesser) -> str:
+def get_build_system(template, url, guesser):
     """Determine the build system template.
 
     If a template is specified, always use that. Otherwise, if a URL
@@ -973,10 +882,11 @@ def get_build_system(template: str, url: str, guesser: BuildSystemAndLanguageGue
     build system it uses. Otherwise, use a generic template by default.
 
     Args:
-        template: ``--template`` argument given to ``spack create``
-        url: ``url`` argument given to ``spack create``
-        guesser: The first_stage_function given to ``spack checksum`` which records the build
-            system it detects
+        template (str): ``--template`` argument given to ``spack create``
+        url (str): ``url`` argument given to ``spack create``
+        args (argparse.Namespace): The arguments given to ``spack create``
+        guesser (BuildSystemGuesser): The first_stage_function given to
+            ``spack checksum`` which records the build system it detects
 
     Returns:
         str: The name of the build system template to use
@@ -1050,7 +960,7 @@ def create(parser, args):
     build_system = get_build_system(args.template, url, guesser)
 
     # Create the package template object
-    constr_args = {"name": name, "versions": versions, "languages": guesser.languages}
+    constr_args = {"name": name, "versions": versions}
     package_class = templates[build_system]
     if package_class != BundlePackageTemplate:
         constr_args["url"] = url

lib/spack/spack/cmd/debug.py

@@ -6,7 +6,6 @@
 import os
 import platform
 import re
-import sys
 from datetime import datetime
 from glob import glob
 
@@ -63,10 +62,9 @@ def create_db_tarball(args):
 
     base = os.path.basename(str(spack.store.STORE.root))
     transform_args = []
-    # Currently --transform and -s are not supported by Windows native tar
     if "GNU" in tar("--version", output=str):
         transform_args = ["--transform", "s/^%s/%s/" % (base, tarball_name)]
-    elif sys.platform != "win32":
+    else:
         transform_args = ["-s", "/^%s/%s/" % (base, tarball_name)]
 
     wd = os.path.dirname(str(spack.store.STORE.root))
@@ -92,6 +90,7 @@ def report(args):
     print("* **Spack:**", get_version())
     print("* **Python:**", platform.python_version())
     print("* **Platform:**", architecture)
+    print("* **Concretizer:**", spack.config.get("config:concretizer"))
 
 
 def debug(parser, args):

lib/spack/spack/cmd/develop.py

@@ -10,10 +10,8 @@
 import spack.cmd
 import spack.config
 import spack.fetch_strategy
-import spack.package_base
 import spack.repo
 import spack.spec
-import spack.stage
 import spack.util.path
 import spack.version
 from spack.cmd.common import arguments
@@ -64,7 +62,7 @@ def change_fn(section):
     spack.config.change_or_add("develop", find_fn, change_fn)
 
 
-def _retrieve_develop_source(spec: spack.spec.Spec, abspath: str) -> None:
+def _retrieve_develop_source(spec, abspath):
     # "steal" the source code via staging API. We ask for a stage
     # to be created, then copy it afterwards somewhere else. It would be
     # better if we can create the `source_path` directly into its final
@@ -73,13 +71,13 @@ def _retrieve_develop_source(spec: spack.spec.Spec, abspath: str) -> None:
     # We construct a package class ourselves, rather than asking for
     # Spec.package, since Spec only allows this when it is concrete
     package = pkg_cls(spec)
-    source_stage: spack.stage.Stage = package.stage[0]
+    source_stage = package.stage[0]
     if isinstance(source_stage.fetcher, spack.fetch_strategy.GitFetchStrategy):
         source_stage.fetcher.get_full_repo = True
         # If we retrieved this version before and cached it, we may have
         # done so without cloning the full git repo; likewise, any
         # mirror might store an instance with truncated history.
-        source_stage.default_fetcher_only = True
+        source_stage.disable_mirrors()
 
     source_stage.fetcher.set_package(package)
     package.stage.steal_source(abspath)

lib/spack/spack/cmd/env.py

@@ -468,30 +468,32 @@ def env_remove(args):
     This removes an environment managed by Spack. Directory environments
     and manifests embedded in repositories should be removed manually.
     """
-    remove_envs = []
+    read_envs = []
     valid_envs = []
     bad_envs = []
+    invalid_envs = []
 
     for env_name in ev.all_environment_names():
         try:
             env = ev.read(env_name)
-            valid_envs.append(env)
+            valid_envs.append(env_name)
 
             if env_name in args.rm_env:
-                remove_envs.append(env)
+                read_envs.append(env)
         except (spack.config.ConfigFormatError, ev.SpackEnvironmentConfigError):
+            invalid_envs.append(env_name)
+
             if env_name in args.rm_env:
                 bad_envs.append(env_name)
 
-    # Check if remove_env is included from another env before trying to remove
-    for env in valid_envs:
-        for remove_env in remove_envs:
+        # Check if env is linked to another before trying to remove
+        for name in valid_envs:
             # don't check if environment is included to itself
-            if env.name == remove_env.name:
+            if name == env_name:
                 continue
-
-            if remove_env.path in env.included_concrete_envs:
-                msg = f'Environment "{remove_env.name}" is being used by environment "{env.name}"'
+            environ = ev.Environment(ev.root(name))
+            if ev.root(env_name) in environ.included_concrete_envs:
+                msg = f'Environment "{env_name}" is being used by environment "{name}"'
                 if args.force:
                     tty.warn(msg)
                 else:
@@ -504,7 +506,7 @@ def env_remove(args):
         if not answer:
             tty.die("Will not remove any environments")
 
-    for env in remove_envs:
+    for env in read_envs:
         name = env.name
         if env.active:
             tty.die(f"Environment {name} can't be removed while activated.")

lib/spack/spack/cmd/gpg.py

@@ -5,12 +5,10 @@
 
 import argparse
 import os
-import tempfile
 
 import spack.binary_distribution
 import spack.mirror
 import spack.paths
-import spack.stage
 import spack.util.gpg
 import spack.util.url
 from spack.cmd.common import arguments
@@ -117,7 +115,6 @@ def setup_parser(subparser):
         help="URL of the mirror where keys will be published",
     )
     publish.add_argument(
-        "--update-index",
         "--rebuild-index",
         action="store_true",
         default=False,
@@ -223,10 +220,9 @@ def gpg_publish(args):
     elif args.mirror_url:
         mirror = spack.mirror.Mirror(args.mirror_url, args.mirror_url)
 
-    with tempfile.TemporaryDirectory(dir=spack.stage.get_stage_root()) as tmpdir:
-        spack.binary_distribution._url_push_keys(
-            mirror, keys=args.keys, tmpdir=tmpdir, update_index=args.update_index
-        )
+    spack.binary_distribution.push_keys(
+        mirror, keys=args.keys, regenerate_index=args.rebuild_index
+    )
 
 
 def gpg(parser, args):

lib/spack/spack/cmd/info.py

@@ -502,7 +502,7 @@ def print_licenses(pkg, args):
 
 def info(parser, args):
     spec = spack.spec.Spec(args.package)
-    pkg_cls = spack.repo.PATH.get_pkg_class(spec.fullname)
+    pkg_cls = spack.repo.PATH.get_pkg_class(spec.name)
     pkg = pkg_cls(spec)
 
     # Output core package information

lib/spack/spack/cmd/versions.py

@@ -23,6 +23,11 @@ def setup_parser(subparser):
     output.add_argument(
         "-s", "--safe", action="store_true", help="only list safe versions of the package"
     )
+    output.add_argument(
+        "--safe-only",
+        action="store_true",
+        help="[deprecated] only list safe versions of the package",
+    )
     output.add_argument(
         "-r", "--remote", action="store_true", help="only list remote versions of the package"
     )
@@ -42,13 +47,17 @@ def versions(parser, args):
 
     safe_versions = pkg.versions
 
+    if args.safe_only:
+        tty.warn('"--safe-only" is deprecated. Use "--safe" instead.')
+        args.safe = args.safe_only
+
     if not (args.remote or args.new):
         if sys.stdout.isatty():
             tty.msg("Safe versions (already checksummed):")
 
         if not safe_versions:
             if sys.stdout.isatty():
-                tty.warn(f"Found no versions for {pkg.name}")
+                tty.warn("Found no versions for {0}".format(pkg.name))
                 tty.debug("Manually add versions to the package.")
         else:
             colify(sorted(safe_versions, reverse=True), indent=2)
@@ -74,12 +83,12 @@ def versions(parser, args):
     if not remote_versions:
         if sys.stdout.isatty():
             if not fetched_versions:
-                tty.warn(f"Found no versions for {pkg.name}")
+                tty.warn("Found no versions for {0}".format(pkg.name))
                 tty.debug(
                     "Check the list_url and list_depth attributes of "
                     "the package to help Spack find versions."
                 )
             else:
-                tty.warn(f"Found no unchecksummed versions for {pkg.name}")
+                tty.warn("Found no unchecksummed versions for {0}".format(pkg.name))
     else:
         colify(sorted(remote_versions, reverse=True), indent=2)

lib/spack/spack/compiler.py

@@ -29,9 +29,6 @@
 
 __all__ = ["Compiler"]
 
-PATH_INSTANCE_VARS = ["cc", "cxx", "f77", "fc"]
-FLAG_INSTANCE_VARS = ["cflags", "cppflags", "cxxflags", "fflags"]
-
 
 @llnl.util.lang.memoized
 def _get_compiler_version_output(compiler_path, version_arg, ignore_errors=()):
@@ -703,30 +700,6 @@ def compiler_environment(self):
             os.environ.clear()
             os.environ.update(backup_env)
 
-    def to_dict(self):
-        flags_dict = {fname: " ".join(fvals) for fname, fvals in self.flags.items()}
-        flags_dict.update(
-            {attr: getattr(self, attr, None) for attr in FLAG_INSTANCE_VARS if hasattr(self, attr)}
-        )
-        result = {
-            "spec": str(self.spec),
-            "paths": {attr: getattr(self, attr, None) for attr in PATH_INSTANCE_VARS},
-            "flags": flags_dict,
-            "operating_system": str(self.operating_system),
-            "target": str(self.target),
-            "modules": self.modules or [],
-            "environment": self.environment or {},
-            "extra_rpaths": self.extra_rpaths or [],
-        }
-
-        if self.enable_implicit_rpaths is not None:
-            result["implicit_rpaths"] = self.enable_implicit_rpaths
-
-        if self.alias:
-            result["alias"] = self.alias
-
-        return result
-
 
 class CompilerAccessError(spack.error.SpackError):
     def __init__(self, compiler, paths):

lib/spack/spack/compilers/__init__.py

@@ -6,11 +6,12 @@
 """This module contains functions related to finding compilers on the
 system and configuring Spack to use multiple compilers.
 """
-import importlib
+import collections
+import itertools
+import multiprocessing.pool
 import os
-import sys
 import warnings
-from typing import Dict, List, Optional
+from typing import Dict, List, Optional, Tuple
 
 import archspec.cpu
 
@@ -21,15 +22,16 @@
 import spack.compiler
 import spack.config
 import spack.error
+import spack.operating_systems
 import spack.paths
 import spack.platforms
-import spack.repo
 import spack.spec
 import spack.version
-from spack.operating_systems import windows_os
 from spack.util.environment import get_path
 from spack.util.naming import mod_to_class
 
+_path_instance_vars = ["cc", "cxx", "f77", "fc"]
+_flags_instance_vars = ["cflags", "cppflags", "cxxflags", "fflags"]
 _other_instance_vars = [
     "modules",
     "operating_system",
@@ -61,10 +63,6 @@
 }
 
 
-#: Tag used to identify packages providing a compiler
-COMPILER_TAG = "compiler"
-
-
 def pkg_spec_for_compiler(cspec):
     """Return the spec of the package that provides the compiler."""
     for spec, package in _compiler_to_pkg.items():
@@ -87,7 +85,29 @@ def converter(cspec_like, *args, **kwargs):
 
 def _to_dict(compiler):
     """Return a dict version of compiler suitable to insert in YAML."""
-    return {"compiler": compiler.to_dict()}
+    d = {}
+    d["spec"] = str(compiler.spec)
+    d["paths"] = dict((attr, getattr(compiler, attr, None)) for attr in _path_instance_vars)
+    d["flags"] = dict((fname, " ".join(fvals)) for fname, fvals in compiler.flags.items())
+    d["flags"].update(
+        dict(
+            (attr, getattr(compiler, attr, None))
+            for attr in _flags_instance_vars
+            if hasattr(compiler, attr)
+        )
+    )
+    d["operating_system"] = str(compiler.operating_system)
+    d["target"] = str(compiler.target)
+    d["modules"] = compiler.modules or []
+    d["environment"] = compiler.environment or {}
+    d["extra_rpaths"] = compiler.extra_rpaths or []
+    if compiler.enable_implicit_rpaths is not None:
+        d["implicit_rpaths"] = compiler.enable_implicit_rpaths
+
+    if compiler.alias:
+        d["alias"] = compiler.alias
+
+    return {"compiler": d}
 
 
 def get_compiler_config(
@@ -107,7 +127,7 @@ def get_compiler_config(
         # Do not init config because there is a non-empty scope
         return config
 
-    find_compilers(scope=scope)
+    _init_compiler_config(configuration, scope=scope)
     config = configuration.get("compilers", scope=scope)
     return config
 
@@ -116,8 +136,125 @@ def get_compiler_config_from_packages(
     configuration: "spack.config.Configuration", *, scope: Optional[str] = None
 ) -> List[Dict]:
     """Return the compiler configuration from packages.yaml"""
-    packages_yaml = configuration.get("packages", scope=scope)
-    return CompilerConfigFactory.from_packages_yaml(packages_yaml)
+    config = configuration.get("packages", scope=scope)
+    if not config:
+        return []
+
+    packages = []
+    compiler_package_names = supported_compilers() + list(package_name_to_compiler_name.keys())
+    for name, entry in config.items():
+        if name not in compiler_package_names:
+            continue
+        externals_config = entry.get("externals", None)
+        if not externals_config:
+            continue
+        packages.extend(_compiler_config_from_package_config(externals_config))
+
+    return packages
+
+
+def _compiler_config_from_package_config(config):
+    compilers = []
+    for entry in config:
+        compiler = _compiler_config_from_external(entry)
+        if compiler:
+            compilers.append(compiler)
+
+    return compilers
+
+
+def _compiler_config_from_external(config):
+    extra_attributes_key = "extra_attributes"
+    compilers_key = "compilers"
+    c_key, cxx_key, fortran_key = "c", "cxx", "fortran"
+
+    # Allow `@x.y.z` instead of `@=x.y.z`
+    spec = spack.spec.parse_with_version_concrete(config["spec"])
+
+    compiler_spec = spack.spec.CompilerSpec(
+        package_name_to_compiler_name.get(spec.name, spec.name), spec.version
+    )
+
+    err_header = f"The external spec '{spec}' cannot be used as a compiler"
+
+    # If extra_attributes is not there I might not want to use this entry as a compiler,
+    # therefore just leave a debug message, but don't be loud with a warning.
+    if extra_attributes_key not in config:
+        tty.debug(f"[{__file__}] {err_header}: missing the '{extra_attributes_key}' key")
+        return None
+    extra_attributes = config[extra_attributes_key]
+
+    # If I have 'extra_attributes' warn if 'compilers' is missing, or we don't have a C compiler
+    if compilers_key not in extra_attributes:
+        warnings.warn(
+            f"{err_header}: missing the '{compilers_key}' key under '{extra_attributes_key}'"
+        )
+        return None
+    attribute_compilers = extra_attributes[compilers_key]
+
+    if c_key not in attribute_compilers:
+        warnings.warn(
+            f"{err_header}: missing the C compiler path under "
+            f"'{extra_attributes_key}:{compilers_key}'"
+        )
+        return None
+    c_compiler = attribute_compilers[c_key]
+
+    # C++ and Fortran compilers are not mandatory, so let's just leave a debug trace
+    if cxx_key not in attribute_compilers:
+        tty.debug(f"[{__file__}] The external spec {spec} does not have a C++ compiler")
+
+    if fortran_key not in attribute_compilers:
+        tty.debug(f"[{__file__}] The external spec {spec} does not have a Fortran compiler")
+
+    # compilers format has cc/fc/f77, externals format has "c/fortran"
+    paths = {
+        "cc": c_compiler,
+        "cxx": attribute_compilers.get(cxx_key, None),
+        "fc": attribute_compilers.get(fortran_key, None),
+        "f77": attribute_compilers.get(fortran_key, None),
+    }
+
+    if not spec.architecture:
+        host_platform = spack.platforms.host()
+        operating_system = host_platform.operating_system("default_os")
+        target = host_platform.target("default_target").microarchitecture
+    else:
+        target = spec.architecture.target
+        if not target:
+            target = spack.platforms.host().target("default_target")
+        target = target.microarchitecture
+
+        operating_system = spec.os
+        if not operating_system:
+            host_platform = spack.platforms.host()
+            operating_system = host_platform.operating_system("default_os")
+
+    compiler_entry = {
+        "compiler": {
+            "spec": str(compiler_spec),
+            "paths": paths,
+            "flags": extra_attributes.get("flags", {}),
+            "operating_system": str(operating_system),
+            "target": str(target.family),
+            "modules": config.get("modules", []),
+            "environment": extra_attributes.get("environment", {}),
+            "extra_rpaths": extra_attributes.get("extra_rpaths", []),
+            "implicit_rpaths": extra_attributes.get("implicit_rpaths", None),
+        }
+    }
+    return compiler_entry
+
+
+def _init_compiler_config(
+    configuration: "spack.config.Configuration", *, scope: Optional[str]
+) -> None:
+    """Compiler search used when Spack has no compilers."""
+    compilers = find_compilers()
+    compilers_dict = []
+    for compiler in compilers:
+        compilers_dict.append(_to_dict(compiler))
+    configuration.set("compilers", compilers_dict, scope=scope)
 
 
 def compiler_config_files():
@@ -141,7 +278,9 @@ def add_compilers_to_config(compilers, scope=None):
         compilers: a list of Compiler objects.
         scope: configuration scope to modify.
     """
-    compiler_config = get_compiler_config(configuration=spack.config.CONFIG, scope=scope)
+    compiler_config = get_compiler_config(
+        configuration=spack.config.CONFIG, scope=scope, init_config=False
+    )
     for compiler in compilers:
         if not compiler.cc:
             tty.debug(f"{compiler.spec} does not have a C compiler")
@@ -190,7 +329,9 @@ def _remove_compiler_from_scope(compiler_spec, scope):
          True if one or more compiler entries were actually removed, False otherwise
     """
     assert scope is not None, "a specific scope is needed when calling this function"
-    compiler_config = get_compiler_config(configuration=spack.config.CONFIG, scope=scope)
+    compiler_config = get_compiler_config(
+        configuration=spack.config.CONFIG, scope=scope, init_config=False
+    )
     filtered_compiler_config = [
         compiler_entry
         for compiler_entry in compiler_config
@@ -239,77 +380,79 @@ def all_compiler_specs(scope=None, init_config=True):
 
 
 def find_compilers(
-    path_hints: Optional[List[str]] = None,
-    *,
-    scope: Optional[str] = None,
-    mixed_toolchain: bool = False,
-    max_workers: Optional[int] = None,
+    path_hints: Optional[List[str]] = None, *, mixed_toolchain=False
 ) -> List["spack.compiler.Compiler"]:
-    """Searches for compiler in the paths given as argument. If any new compiler is found, the
-    configuration is updated, and the list of new compiler objects is returned.
+    """Return the list of compilers found in the paths given as arguments.
 
     Args:
         path_hints: list of path hints where to look for. A sensible default based on the ``PATH``
             environment variable will be used if the value is None
-        scope: configuration scope to modify
         mixed_toolchain: allow mixing compilers from different toolchains if otherwise missing for
             a certain language
-        max_workers: number of processes used to search for compilers
     """
-    import spack.detection
-
-    known_compilers = set(all_compilers(init_config=False))
-
     if path_hints is None:
         path_hints = get_path("PATH")
     default_paths = fs.search_paths_for_executables(*path_hints)
-    if sys.platform == "win32":
-        default_paths.extend(windows_os.WindowsOs().compiler_search_paths)
-    compiler_pkgs = spack.repo.PATH.packages_with_tags(COMPILER_TAG, full=True)
 
-    detected_packages = spack.detection.by_path(
-        compiler_pkgs, path_hints=default_paths, max_workers=max_workers
+    # To detect the version of the compilers, we dispatch a certain number
+    # of function calls to different workers. Here we construct the list
+    # of arguments for each call.
+    arguments = []
+    for o in all_os_classes():
+        search_paths = getattr(o, "compiler_search_paths", default_paths)
+        arguments.extend(arguments_to_detect_version_fn(o, search_paths))
+
+    # Here we map the function arguments to the corresponding calls
+    tp = multiprocessing.pool.ThreadPool()
+    try:
+        detected_versions = tp.map(detect_version, arguments)
+    finally:
+        tp.close()
+
+    def valid_version(item: Tuple[Optional[DetectVersionArgs], Optional[str]]) -> bool:
+        value, error = item
+        if error is None:
+            return True
+        try:
+            # This will fail on Python 2.6 if a non ascii
+            # character is in the error
+            tty.debug(error)
+        except UnicodeEncodeError:
+            pass
+        return False
+
+    def remove_errors(
+        item: Tuple[Optional[DetectVersionArgs], Optional[str]]
+    ) -> DetectVersionArgs:
+        value, _ = item
+        assert value is not None
+        return value
+
+    return make_compiler_list(
+        [remove_errors(detected) for detected in detected_versions if valid_version(detected)],
+        mixed_toolchain=mixed_toolchain,
     )
 
-    valid_compilers = {}
-    for name, detected in detected_packages.items():
-        compilers = [x for x in detected if CompilerConfigFactory.from_external_spec(x.spec)]
-        if not compilers:
-            continue
-        valid_compilers[name] = compilers
 
-    def _has_fortran_compilers(x):
-        if "compilers" not in x.spec.extra_attributes:
-            return False
+def find_new_compilers(
+    path_hints: Optional[List[str]] = None,
+    scope: Optional[str] = None,
+    *,
+    mixed_toolchain: bool = False,
+):
+    """Same as ``find_compilers`` but return only the compilers that are not
+    already in compilers.yaml.
 
-        return "fortran" in x.spec.extra_attributes["compilers"]
+    Args:
+        path_hints: list of path hints where to look for. A sensible default based on the ``PATH``
+            environment variable will be used if the value is None
+        scope: scope to look for a compiler. If None consider the merged configuration.
+        mixed_toolchain: allow mixing compilers from different toolchains if otherwise missing for
+            a certain language
+    """
+    compilers = find_compilers(path_hints, mixed_toolchain=mixed_toolchain)
 
-    if mixed_toolchain:
-        gccs = [x for x in valid_compilers.get("gcc", []) if _has_fortran_compilers(x)]
-        if gccs:
-            best_gcc = sorted(
-                gccs, key=lambda x: spack.spec.parse_with_version_concrete(x.spec).version
-            )[-1]
-            gfortran = best_gcc.spec.extra_attributes["compilers"]["fortran"]
-            for name in ("llvm", "apple-clang"):
-                if name not in valid_compilers:
-                    continue
-                candidates = valid_compilers[name]
-                for candidate in candidates:
-                    if _has_fortran_compilers(candidate):
-                        continue
-                    candidate.spec.extra_attributes["compilers"]["fortran"] = gfortran
-
-    new_compilers = []
-    for name, detected in valid_compilers.items():
-        for config in CompilerConfigFactory.from_specs([x.spec for x in detected]):
-            c = _compiler_from_config_entry(config["compiler"])
-            if c in known_compilers:
-                continue
-            new_compilers.append(c)
-
-    add_compilers_to_config(new_compilers, scope=scope)
-    return new_compilers
+    return select_new_compilers(compilers, scope)
 
 
 def select_new_compilers(compilers, scope=None):
@@ -319,9 +462,7 @@ def select_new_compilers(compilers, scope=None):
     compilers_not_in_config = []
     for c in compilers:
         arch_spec = spack.spec.ArchSpec((None, c.operating_system, c.target))
-        same_specs = compilers_for_spec(
-            c.spec, arch_spec=arch_spec, scope=scope, init_config=False
-        )
+        same_specs = compilers_for_spec(c.spec, arch_spec, scope=scope, init_config=False)
         if not same_specs:
             compilers_not_in_config.append(c)
 
@@ -369,9 +510,8 @@ def replace_apple_clang(name):
     return [replace_apple_clang(name) for name in all_compiler_module_names()]
 
 
-@llnl.util.lang.memoized
 def all_compiler_module_names() -> List[str]:
-    return list(llnl.util.lang.list_modules(spack.paths.compilers_path))
+    return [name for name in llnl.util.lang.list_modules(spack.paths.compilers_path)]
 
 
 @_auto_compiler_spec
@@ -391,12 +531,7 @@ def find(compiler_spec, scope=None, init_config=True):
 def find_specs_by_arch(compiler_spec, arch_spec, scope=None, init_config=True):
     """Return specs of available compilers that match the supplied
     compiler spec.  Return an empty list if nothing found."""
-    return [
-        c.spec
-        for c in compilers_for_spec(
-            compiler_spec, arch_spec=arch_spec, scope=scope, init_config=init_config
-        )
-    ]
+    return [c.spec for c in compilers_for_spec(compiler_spec, arch_spec, scope, True, init_config)]
 
 
 def all_compilers(scope=None, init_config=True):
@@ -418,11 +553,14 @@ def all_compilers_from(configuration, scope=None, init_config=True):
 
 
 @_auto_compiler_spec
-def compilers_for_spec(compiler_spec, *, arch_spec=None, scope=None, init_config=True):
+def compilers_for_spec(
+    compiler_spec, arch_spec=None, scope=None, use_cache=True, init_config=True
+):
     """This gets all compilers that satisfy the supplied CompilerSpec.
     Returns an empty list if none are found.
     """
     config = all_compilers_config(spack.config.CONFIG, scope=scope, init_config=init_config)
+
     matches = set(find(compiler_spec, scope, init_config))
     compilers = []
     for cspec in matches:
@@ -431,7 +569,7 @@ def compilers_for_spec(compiler_spec, *, arch_spec=None, scope=None, init_config
 
 
 def compilers_for_arch(arch_spec, scope=None):
-    config = all_compilers_config(spack.config.CONFIG, scope=scope, init_config=False)
+    config = all_compilers_config(spack.config.CONFIG, scope=scope)
     return list(get_compilers(config, arch_spec=arch_spec))
 
 
@@ -463,15 +601,13 @@ def compiler_from_dict(items):
     os = items.get("operating_system", None)
     target = items.get("target", None)
 
-    if not (
-        "paths" in items and all(n in items["paths"] for n in spack.compiler.PATH_INSTANCE_VARS)
-    ):
+    if not ("paths" in items and all(n in items["paths"] for n in _path_instance_vars)):
         raise InvalidCompilerConfigurationError(cspec)
 
     cls = class_for_compiler_name(cspec.name)
 
     compiler_paths = []
-    for c in spack.compiler.PATH_INSTANCE_VARS:
+    for c in _path_instance_vars:
         compiler_path = items["paths"][c]
         if compiler_path != "None":
             compiler_paths.append(compiler_path)
@@ -630,7 +766,7 @@ def class_for_compiler_name(compiler_name):
         submodule_name = compiler_name.replace("-", "_")
 
     module_name = ".".join(["spack", "compilers", submodule_name])
-    module_obj = importlib.import_module(module_name)
+    module_obj = __import__(module_name, fromlist=[None])
     cls = getattr(module_obj, mod_to_class(compiler_name))
 
     # make a note of the name in the module so we can get to it easily.
@@ -639,10 +775,272 @@ def class_for_compiler_name(compiler_name):
     return cls
 
 
+def all_os_classes():
+    """
+    Return the list of classes for all operating systems available on
+    this platform
+    """
+    classes = []
+
+    platform = spack.platforms.host()
+    for os_class in platform.operating_sys.values():
+        classes.append(os_class)
+
+    return classes
+
+
 def all_compiler_types():
     return [class_for_compiler_name(c) for c in supported_compilers()]
 
 
+#: Gathers the attribute values by which a detected compiler is considered
+#: unique in Spack.
+#:
+#:  - os: the operating system
+#:  - compiler_name: the name of the compiler (e.g. 'gcc', 'clang', etc.)
+#:  - version: the version of the compiler
+#:
+CompilerID = collections.namedtuple("CompilerID", ["os", "compiler_name", "version"])
+
+#: Variations on a matched compiler name
+NameVariation = collections.namedtuple("NameVariation", ["prefix", "suffix"])
+
+#: Groups together the arguments needed by `detect_version`. The four entries
+#: in the tuple are:
+#:
+#: - id: An instance of the CompilerID named tuple (version can be set to None
+#:       as it will be detected later)
+#: - variation: a NameVariation for file being tested
+#: - language: compiler language being tested (one of 'cc', 'cxx', 'fc', 'f77')
+#: - path: full path to the executable being tested
+#:
+DetectVersionArgs = collections.namedtuple(
+    "DetectVersionArgs", ["id", "variation", "language", "path"]
+)
+
+
+def arguments_to_detect_version_fn(
+    operating_system: spack.operating_systems.OperatingSystem, paths: List[str]
+) -> List[DetectVersionArgs]:
+    """Returns a list of DetectVersionArgs tuples to be used in a
+    corresponding function to detect compiler versions.
+
+    The ``operating_system`` instance can customize the behavior of this
+    function by providing a method called with the same name.
+
+    Args:
+        operating_system: the operating system on which we are looking for compilers
+        paths: paths to search for compilers
+
+    Returns:
+        List of DetectVersionArgs tuples. Each item in the list will be later
+        mapped to the corresponding function call to detect the version of the
+        compilers in this OS.
+    """
+
+    def _default(search_paths: List[str]) -> List[DetectVersionArgs]:
+        command_arguments: List[DetectVersionArgs] = []
+        files_to_be_tested = fs.files_in(*search_paths)
+        for compiler_name in supported_compilers_for_host_platform():
+            compiler_cls = class_for_compiler_name(compiler_name)
+
+            for language in ("cc", "cxx", "f77", "fc"):
+                # Select only the files matching a regexp
+                for (file, full_path), regexp in itertools.product(
+                    files_to_be_tested, compiler_cls.search_regexps(language)
+                ):
+                    match = regexp.match(file)
+                    if match:
+                        compiler_id = CompilerID(operating_system, compiler_name, None)
+                        detect_version_args = DetectVersionArgs(
+                            id=compiler_id,
+                            variation=NameVariation(*match.groups()),
+                            language=language,
+                            path=full_path,
+                        )
+                        command_arguments.append(detect_version_args)
+
+        return command_arguments
+
+    fn = getattr(operating_system, "arguments_to_detect_version_fn", _default)
+    return fn(paths)
+
+
+def detect_version(
+    detect_version_args: DetectVersionArgs,
+) -> Tuple[Optional[DetectVersionArgs], Optional[str]]:
+    """Computes the version of a compiler and adds it to the information
+    passed as input.
+
+    As this function is meant to be executed by worker processes it won't
+    raise any exception but instead will return a (value, error) tuple that
+    needs to be checked by the code dispatching the calls.
+
+    Args:
+        detect_version_args: information on the compiler for which we should detect the version.
+
+    Returns:
+        A ``(DetectVersionArgs, error)`` tuple. If ``error`` is ``None`` the
+        version of the compiler was computed correctly and the first argument
+        of the tuple will contain it. Otherwise ``error`` is a string
+        containing an explanation on why the version couldn't be computed.
+    """
+
+    def _default(fn_args):
+        compiler_id = fn_args.id
+        language = fn_args.language
+        compiler_cls = class_for_compiler_name(compiler_id.compiler_name)
+        path = fn_args.path
+
+        # Get compiler names and the callback to detect their versions
+        callback = getattr(compiler_cls, f"{language}_version")
+
+        try:
+            version = callback(path)
+            if version and str(version).strip() and version != "unknown":
+                value = fn_args._replace(id=compiler_id._replace(version=version))
+                return value, None
+
+            error = f"Couldn't get version for compiler {path}".format(path)
+        except spack.util.executable.ProcessError as e:
+            error = f"Couldn't get version for compiler {path}\n" + str(e)
+        except spack.util.executable.ProcessTimeoutError as e:
+            error = f"Couldn't get version for compiler {path}\n" + str(e)
+        except Exception as e:
+            # Catching "Exception" here is fine because it just
+            # means something went wrong running a candidate executable.
+            error = "Error while executing candidate compiler {0}" "\n{1}: {2}".format(
+                path, e.__class__.__name__, str(e)
+            )
+        return None, error
+
+    operating_system = detect_version_args.id.os
+    fn = getattr(operating_system, "detect_version", _default)
+    return fn(detect_version_args)
+
+
+def make_compiler_list(
+    detected_versions: List[DetectVersionArgs], mixed_toolchain: bool = False
+) -> List["spack.compiler.Compiler"]:
+    """Process a list of detected versions and turn them into a list of
+    compiler specs.
+
+    Args:
+        detected_versions: list of DetectVersionArgs containing a valid version
+        mixed_toolchain: allow mixing compilers from different toolchains if langauge is missing
+
+    Returns:
+        list: list of Compiler objects
+    """
+    group_fn = lambda x: (x.id, x.variation, x.language)
+    sorted_compilers = sorted(detected_versions, key=group_fn)
+
+    # Gather items in a dictionary by the id, name variation and language
+    compilers_d: Dict[CompilerID, Dict[NameVariation, dict]] = {}
+    for sort_key, group in itertools.groupby(sorted_compilers, key=group_fn):
+        compiler_id, name_variation, language = sort_key
+        by_compiler_id = compilers_d.setdefault(compiler_id, {})
+        by_name_variation = by_compiler_id.setdefault(name_variation, {})
+        by_name_variation[language] = next(x.path for x in group)
+
+    def _default_make_compilers(cmp_id, paths):
+        operating_system, compiler_name, version = cmp_id
+        compiler_cls = class_for_compiler_name(compiler_name)
+        spec = spack.spec.CompilerSpec(compiler_cls.name, f"={version}")
+        paths = [paths.get(x, None) for x in ("cc", "cxx", "f77", "fc")]
+        # TODO: johnwparent - revist the following line as per discussion at:
+        # https://github.com/spack/spack/pull/33385/files#r1040036318
+        target = archspec.cpu.host()
+        compiler = compiler_cls(spec, operating_system, str(target.family), paths)
+        return [compiler]
+
+    # For compilers with the same compiler id:
+    #
+    # - Prefer with C compiler to without
+    # - Prefer with C++ compiler to without
+    # - Prefer no variations to variations (e.g., clang to clang-gpu)
+    #
+    sort_fn = lambda variation: (
+        "cc" not in by_compiler_id[variation],  # None last
+        "cxx" not in by_compiler_id[variation],  # None last
+        getattr(variation, "prefix", None),
+        getattr(variation, "suffix", None),
+    )
+
+    # Flatten to a list of compiler id, primary variation and compiler dictionary
+    flat_compilers: List[Tuple[CompilerID, NameVariation, dict]] = []
+    for compiler_id, by_compiler_id in compilers_d.items():
+        ordered = sorted(by_compiler_id, key=sort_fn)
+        selected_variation = ordered[0]
+        selected = by_compiler_id[selected_variation]
+
+        # Fill any missing parts from subsequent entries (without mixing toolchains)
+        for lang in ["cxx", "f77", "fc"]:
+            if lang not in selected:
+                next_lang = next(
+                    (by_compiler_id[v][lang] for v in ordered if lang in by_compiler_id[v]), None
+                )
+                if next_lang:
+                    selected[lang] = next_lang
+
+        flat_compilers.append((compiler_id, selected_variation, selected))
+
+    # Next, fill out the blanks of missing compilers by creating a mixed toolchain (if requested)
+    if mixed_toolchain:
+        make_mixed_toolchain(flat_compilers)
+
+    # Finally, create the compiler list
+    compilers: List["spack.compiler.Compiler"] = []
+    for compiler_id, _, compiler in flat_compilers:
+        make_compilers = getattr(compiler_id.os, "make_compilers", _default_make_compilers)
+        candidates = make_compilers(compiler_id, compiler)
+        compilers.extend(x for x in candidates if x.cc is not None)
+
+    return compilers
+
+
+def make_mixed_toolchain(compilers: List[Tuple[CompilerID, NameVariation, dict]]) -> None:
+    """Add missing compilers across toolchains when they are missing for a particular language.
+    This currently only adds the most sensible gfortran to (apple)-clang if it doesn't have a
+    fortran compiler (no flang)."""
+
+    # First collect the clangs that are missing a fortran compiler
+    clangs_without_flang = [
+        (id, variation, compiler)
+        for id, variation, compiler in compilers
+        if id.compiler_name in ("clang", "apple-clang")
+        and "f77" not in compiler
+        and "fc" not in compiler
+    ]
+    if not clangs_without_flang:
+        return
+
+    # Filter on GCCs with fortran compiler
+    gccs_with_fortran = [
+        (id, variation, compiler)
+        for id, variation, compiler in compilers
+        if id.compiler_name == "gcc" and "f77" in compiler and "fc" in compiler
+    ]
+
+    # Sort these GCCs by "best variation" (no prefix / suffix first)
+    gccs_with_fortran.sort(
+        key=lambda x: (getattr(x[1], "prefix", None), getattr(x[1], "suffix", None))
+    )
+
+    # Attach the optimal GCC fortran compiler to the clangs that don't have one
+    for clang_id, _, clang_compiler in clangs_without_flang:
+        gcc_compiler = next(
+            (gcc[2] for gcc in gccs_with_fortran if gcc[0].os == clang_id.os), None
+        )
+
+        if not gcc_compiler:
+            continue
+
+        # Update the fc / f77 entries
+        clang_compiler["f77"] = gcc_compiler["f77"]
+        clang_compiler["fc"] = gcc_compiler["fc"]
+
+
 def is_mixed_toolchain(compiler):
     """Returns True if the current compiler is a mixed toolchain,
     False otherwise.
@@ -689,164 +1087,20 @@ def name_matches(name, name_list):
     return False
 
 
-_EXTRA_ATTRIBUTES_KEY = "extra_attributes"
-_COMPILERS_KEY = "compilers"
-_C_KEY = "c"
-_CXX_KEY, _FORTRAN_KEY = "cxx", "fortran"
-
-
-class CompilerConfigFactory:
-    """Class aggregating all ways of constructing a list of compiler config entries."""
-
-    @staticmethod
-    def from_specs(specs: List["spack.spec.Spec"]) -> List[dict]:
-        result = []
-        compiler_package_names = supported_compilers() + list(package_name_to_compiler_name.keys())
-        for s in specs:
-            if s.name not in compiler_package_names:
-                continue
-
-            candidate = CompilerConfigFactory.from_external_spec(s)
-            if candidate is None:
-                continue
-
-            result.append(candidate)
-        return result
-
-    @staticmethod
-    def from_packages_yaml(packages_yaml) -> List[dict]:
-        compiler_specs = []
-        compiler_package_names = supported_compilers() + list(package_name_to_compiler_name.keys())
-        for name, entry in packages_yaml.items():
-            if name not in compiler_package_names:
-                continue
-
-            externals_config = entry.get("externals", None)
-            if not externals_config:
-                continue
-
-            current_specs = []
-            for current_external in externals_config:
-                compiler = CompilerConfigFactory._spec_from_external_config(current_external)
-                if compiler:
-                    current_specs.append(compiler)
-            compiler_specs.extend(current_specs)
-
-        return CompilerConfigFactory.from_specs(compiler_specs)
-
-    @staticmethod
-    def _spec_from_external_config(config):
-        # Allow `@x.y.z` instead of `@=x.y.z`
-        err_header = f"The external spec '{config['spec']}' cannot be used as a compiler"
-        # If extra_attributes is not there I might not want to use this entry as a compiler,
-        # therefore just leave a debug message, but don't be loud with a warning.
-        if _EXTRA_ATTRIBUTES_KEY not in config:
-            tty.debug(f"[{__file__}] {err_header}: missing the '{_EXTRA_ATTRIBUTES_KEY}' key")
-            return None
-        extra_attributes = config[_EXTRA_ATTRIBUTES_KEY]
-        result = spack.spec.Spec(
-            str(spack.spec.parse_with_version_concrete(config["spec"])),
-            external_modules=config.get("modules"),
-        )
-        result.extra_attributes = extra_attributes
-        return result
-
-    @staticmethod
-    def from_external_spec(spec: "spack.spec.Spec") -> Optional[dict]:
-        spec = spack.spec.parse_with_version_concrete(spec)
-        extra_attributes = getattr(spec, _EXTRA_ATTRIBUTES_KEY, None)
-        if extra_attributes is None:
-            return None
-
-        paths = CompilerConfigFactory._extract_compiler_paths(spec)
-        if paths is None:
-            return None
-
-        compiler_spec = spack.spec.CompilerSpec(
-            package_name_to_compiler_name.get(spec.name, spec.name), spec.version
-        )
-
-        operating_system, target = CompilerConfigFactory._extract_os_and_target(spec)
-
-        compiler_entry = {
-            "compiler": {
-                "spec": str(compiler_spec),
-                "paths": paths,
-                "flags": extra_attributes.get("flags", {}),
-                "operating_system": str(operating_system),
-                "target": str(target.family),
-                "modules": getattr(spec, "external_modules", []),
-                "environment": extra_attributes.get("environment", {}),
-                "extra_rpaths": extra_attributes.get("extra_rpaths", []),
-                "implicit_rpaths": extra_attributes.get("implicit_rpaths", None),
-            }
-        }
-        return compiler_entry
-
-    @staticmethod
-    def _extract_compiler_paths(spec: "spack.spec.Spec") -> Optional[Dict[str, str]]:
-        err_header = f"The external spec '{spec}' cannot be used as a compiler"
-        extra_attributes = spec.extra_attributes
-        # If I have 'extra_attributes' warn if 'compilers' is missing,
-        # or we don't have a C compiler
-        if _COMPILERS_KEY not in extra_attributes:
-            warnings.warn(
-                f"{err_header}: missing the '{_COMPILERS_KEY}' key under '{_EXTRA_ATTRIBUTES_KEY}'"
-            )
-            return None
-        attribute_compilers = extra_attributes[_COMPILERS_KEY]
-
-        if _C_KEY not in attribute_compilers:
-            warnings.warn(
-                f"{err_header}: missing the C compiler path under "
-                f"'{_EXTRA_ATTRIBUTES_KEY}:{_COMPILERS_KEY}'"
-            )
-            return None
-        c_compiler = attribute_compilers[_C_KEY]
-
-        # C++ and Fortran compilers are not mandatory, so let's just leave a debug trace
-        if _CXX_KEY not in attribute_compilers:
-            tty.debug(f"[{__file__}] The external spec {spec} does not have a C++ compiler")
-
-        if _FORTRAN_KEY not in attribute_compilers:
-            tty.debug(f"[{__file__}] The external spec {spec} does not have a Fortran compiler")
-
-        # compilers format has cc/fc/f77, externals format has "c/fortran"
-        return {
-            "cc": c_compiler,
-            "cxx": attribute_compilers.get(_CXX_KEY, None),
-            "fc": attribute_compilers.get(_FORTRAN_KEY, None),
-            "f77": attribute_compilers.get(_FORTRAN_KEY, None),
-        }
-
-    @staticmethod
-    def _extract_os_and_target(spec: "spack.spec.Spec"):
-        if not spec.architecture:
-            host_platform = spack.platforms.host()
-            operating_system = host_platform.operating_system("default_os")
-            target = host_platform.target("default_target").microarchitecture
-        else:
-            target = spec.architecture.target
-            if not target:
-                target = spack.platforms.host().target("default_target")
-            target = target.microarchitecture
-
-            operating_system = spec.os
-            if not operating_system:
-                host_platform = spack.platforms.host()
-                operating_system = host_platform.operating_system("default_os")
-        return operating_system, target
-
-
 class InvalidCompilerConfigurationError(spack.error.SpackError):
     def __init__(self, compiler_spec):
         super().__init__(
-            f'Invalid configuration for [compiler "{compiler_spec}"]: ',
-            f"Compiler configuration must contain entries for "
-            f"all compilers: {spack.compiler.PATH_INSTANCE_VARS}",
+            'Invalid configuration for [compiler "%s"]: ' % compiler_spec,
+            "Compiler configuration must contain entries for all compilers: %s"
+            % _path_instance_vars,
         )
 
 
+class NoCompilersError(spack.error.SpackError):
+    def __init__(self):
+        super().__init__("Spack could not find any compilers!")
+
+
 class UnknownCompilerError(spack.error.SpackError):
     def __init__(self, compiler_name):
         super().__init__("Spack doesn't support the requested compiler: {0}".format(compiler_name))
@@ -857,3 +1111,25 @@ def __init__(self, compiler_spec, target):
         super().__init__(
             "No compilers for operating system %s satisfy spec %s" % (target, compiler_spec)
         )
+
+
+class CompilerDuplicateError(spack.error.SpackError):
+    def __init__(self, compiler_spec, arch_spec):
+        config_file_to_duplicates = get_compiler_duplicates(compiler_spec, arch_spec)
+        duplicate_table = list((x, len(y)) for x, y in config_file_to_duplicates.items())
+        descriptor = lambda num: "time" if num == 1 else "times"
+        duplicate_msg = lambda cfgfile, count: "{0}: {1} {2}".format(
+            cfgfile, str(count), descriptor(count)
+        )
+        msg = (
+            "Compiler configuration contains entries with duplicate"
+            + " specification ({0}, {1})".format(compiler_spec, arch_spec)
+            + " in the following files:\n\t"
+            + "\n\t".join(duplicate_msg(x, y) for x, y in duplicate_table)
+        )
+        super().__init__(msg)
+
+
+class CompilerSpecInsufficientlySpecificError(spack.error.SpackError):
+    def __init__(self, compiler_spec):
+        super().__init__("Multiple compilers satisfy spec %s" % compiler_spec)

lib/spack/spack/compilers/msvc.py

@@ -223,30 +223,6 @@ def get_oneapi_root(pth: str):
             )
         self.msvc_compiler_environment = CmdCall(*env_cmds)
 
-    @property
-    def cxx11_flag(self):
-        return "/std:c++11"
-
-    @property
-    def cxx14_flag(self):
-        return "/std:c++14"
-
-    @property
-    def cxx17_flag(self):
-        return "/std:c++17"
-
-    @property
-    def cxx20_flag(self):
-        return "/std:c++20"
-
-    @property
-    def c11_flag(self):
-        return "/std:c11"
-
-    @property
-    def c17_flag(self):
-        return "/std:c17"
-
     @property
     def msvc_version(self):
         """This is the VCToolset version *NOT* the actual version of the cl compiler

lib/spack/spack/concretize.py

@@ -2,12 +2,31 @@
 # Spack Project Developers. See the top-level COPYRIGHT file for details.
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
 """
-(DEPRECATED) Used to contain the code for the original concretizer
+Functions here are used to take abstract specs and make them concrete.
+For example, if a spec asks for a version between 1.8 and 1.9, these
+functions might take will take the most recent 1.9 version of the
+package available.  Or, if the user didn't specify a compiler for a
+spec, then this will assign a compiler to the spec based on defaults
+or user preferences.
+
+TODO: make this customizable and allow users to configure
+      concretization  policies.
 """
+import functools
+import platform
+import tempfile
 from contextlib import contextmanager
 from itertools import chain
+from typing import Union
 
+import archspec.cpu
+
+import llnl.util.lang
+import llnl.util.tty as tty
+
+import spack.abi
 import spack.compilers
 import spack.config
 import spack.environment
@@ -18,20 +37,639 @@
 import spack.target
 import spack.tengine
 import spack.util.path
+import spack.variant as vt
+from spack.package_prefs import PackagePrefs, is_spec_buildable, spec_externals
+from spack.version import ClosedOpenRange, VersionList, ver
+
+#: impements rudimentary logic for ABI compatibility
+_abi: Union[spack.abi.ABI, llnl.util.lang.Singleton] = llnl.util.lang.Singleton(
+    lambda: spack.abi.ABI()
+)
+
+
+@functools.total_ordering
+class reverse_order:
+    """Helper for creating key functions.
+
+    This is a wrapper that inverts the sense of the natural
+    comparisons on the object.
+    """
+
+    def __init__(self, value):
+        self.value = value
+
+    def __eq__(self, other):
+        return other.value == self.value
+
+    def __lt__(self, other):
+        return other.value < self.value
 
 
 class Concretizer:
-    """(DEPRECATED) Only contains logic to enable/disable compiler existence checks."""
+    """You can subclass this class to override some of the default
+    concretization strategies, or you can override all of them.
+    """
 
     #: Controls whether we check that compiler versions actually exist
     #: during concretization. Used for testing and for mirror creation
     check_for_compiler_existence = None
 
-    def __init__(self):
+    #: Packages that the old concretizer cannot deal with correctly, and cannot build anyway.
+    #: Those will not be considered as providers for virtuals.
+    non_buildable_packages = {"glibc", "musl"}
+
+    def __init__(self, abstract_spec=None):
         if Concretizer.check_for_compiler_existence is None:
             Concretizer.check_for_compiler_existence = not spack.config.get(
                 "config:install_missing_compilers", False
             )
+        self.abstract_spec = abstract_spec
+        self._adjust_target_answer_generator = None
+
+    def concretize_develop(self, spec):
+        """
+        Add ``dev_path=*`` variant to packages built from local source.
+        """
+        env = spack.environment.active_environment()
+        dev_info = env.dev_specs.get(spec.name, {}) if env else {}
+        if not dev_info:
+            return False
+
+        path = spack.util.path.canonicalize_path(dev_info["path"], default_wd=env.path)
+
+        if "dev_path" in spec.variants:
+            assert spec.variants["dev_path"].value == path
+            changed = False
+        else:
+            spec.variants.setdefault("dev_path", vt.SingleValuedVariant("dev_path", path))
+            changed = True
+        changed |= spec.constrain(dev_info["spec"])
+        return changed
+
+    def _valid_virtuals_and_externals(self, spec):
+        """Returns a list of candidate virtual dep providers and external
+        packages that coiuld be used to concretize a spec.
+
+        Preferred specs come first in the list.
+        """
+        # First construct a list of concrete candidates to replace spec with.
+        candidates = [spec]
+        pref_key = lambda spec: 0  # no-op pref key
+
+        if spec.virtual:
+            candidates = [
+                s
+                for s in spack.repo.PATH.providers_for(spec)
+                if s.name not in self.non_buildable_packages
+            ]
+            if not candidates:
+                raise spack.error.UnsatisfiableProviderSpecError(candidates[0], spec)
+
+            # Find nearest spec in the DAG (up then down) that has prefs.
+            spec_w_prefs = find_spec(
+                spec, lambda p: PackagePrefs.has_preferred_providers(p.name, spec.name), spec
+            )  # default to spec itself.
+
+            # Create a key to sort candidates by the prefs we found
+            pref_key = PackagePrefs(spec_w_prefs.name, "providers", spec.name)
+
+        # For each candidate package, if it has externals, add those
+        # to the usable list.  if it's not buildable, then *only* add
+        # the externals.
+        usable = []
+        for cspec in candidates:
+            if is_spec_buildable(cspec):
+                usable.append(cspec)
+
+            externals = spec_externals(cspec)
+            for ext in externals:
+                if ext.intersects(spec):
+                    usable.append(ext)
+
+        # If nothing is in the usable list now, it's because we aren't
+        # allowed to build anything.
+        if not usable:
+            raise NoBuildError(spec)
+
+        # Use a sort key to order the results
+        return sorted(
+            usable,
+            key=lambda spec: (
+                not spec.external,  # prefer externals
+                pref_key(spec),  # respect prefs
+                spec.name,  # group by name
+                reverse_order(spec.versions),  # latest version
+                spec,  # natural order
+            ),
+        )
+
+    def choose_virtual_or_external(self, spec: spack.spec.Spec):
+        """Given a list of candidate virtual and external packages, try to
+        find one that is most ABI compatible.
+        """
+        candidates = self._valid_virtuals_and_externals(spec)
+        if not candidates:
+            return candidates
+
+        # Find the nearest spec in the dag that has a compiler.  We'll
+        # use that spec to calibrate compiler compatibility.
+        abi_exemplar = find_spec(spec, lambda x: x.compiler)
+        if abi_exemplar is None:
+            abi_exemplar = spec.root
+
+        # Sort candidates from most to least compatibility.
+        #   We reverse because True > False.
+        #   Sort is stable, so candidates keep their order.
+        return sorted(
+            candidates,
+            reverse=True,
+            key=lambda spec: (
+                _abi.compatible(spec, abi_exemplar, loose=True),
+                _abi.compatible(spec, abi_exemplar),
+            ),
+        )
+
+    def concretize_version(self, spec):
+        """If the spec is already concrete, return.  Otherwise take
+        the preferred version from spackconfig, and default to the package's
+        version if there are no available versions.
+
+        TODO: In many cases we probably want to look for installed
+              versions of each package and use an installed version
+              if we can link to it.  The policy implemented here will
+              tend to rebuild a lot of stuff becasue it will prefer
+              a compiler in the spec to any compiler already-
+              installed things were built with.  There is likely
+              some better policy that finds some middle ground
+              between these two extremes.
+        """
+        # return if already concrete.
+        if spec.versions.concrete:
+            return False
+
+        # List of versions we could consider, in sorted order
+        pkg_versions = spec.package_class.versions
+        usable = [v for v in pkg_versions if any(v.intersects(sv) for sv in spec.versions)]
+
+        yaml_prefs = PackagePrefs(spec.name, "version")
+
+        # The keys below show the order of precedence of factors used
+        # to select a version when concretizing.  The item with
+        # the "largest" key will be selected.
+        #
+        # NOTE: When COMPARING VERSIONS, the '@develop' version is always
+        #       larger than other versions.  BUT when CONCRETIZING,
+        #       the largest NON-develop version is selected by default.
+        keyfn = lambda v: (
+            # ------- Special direction from the user
+            # Respect order listed in packages.yaml
+            -yaml_prefs(v),
+            # The preferred=True flag (packages or packages.yaml or both?)
+            pkg_versions.get(v).get("preferred", False),
+            # ------- Regular case: use latest non-develop version by default.
+            # Avoid @develop version, which would otherwise be the "largest"
+            # in straight version comparisons
+            not v.isdevelop(),
+            # Compare the version itself
+            # This includes the logic:
+            #    a) develop > everything (disabled by "not v.isdevelop() above)
+            #    b) numeric > non-numeric
+            #    c) Numeric or string comparison
+            v,
+        )
+        usable.sort(key=keyfn, reverse=True)
+
+        if usable:
+            spec.versions = ver([usable[0]])
+        else:
+            # We don't know of any SAFE versions that match the given
+            # spec.  Grab the spec's versions and grab the highest
+            # *non-open* part of the range of versions it specifies.
+            # Someone else can raise an error if this happens,
+            # e.g. when we go to fetch it and don't know how.  But it
+            # *might* work.
+            if not spec.versions or spec.versions == VersionList([":"]):
+                raise NoValidVersionError(spec)
+            else:
+                last = spec.versions[-1]
+                if isinstance(last, ClosedOpenRange):
+                    range_as_version = VersionList([last]).concrete_range_as_version
+                    if range_as_version:
+                        spec.versions = ver([range_as_version])
+                    else:
+                        raise NoValidVersionError(spec)
+                else:
+                    spec.versions = ver([last])
+
+        return True  # Things changed
+
+    def concretize_architecture(self, spec):
+        """If the spec is empty provide the defaults of the platform. If the
+        architecture is not a string type, then check if either the platform,
+        target or operating system are concretized. If any of the fields are
+        changed then return True. If everything is concretized (i.e the
+        architecture attribute is a namedtuple of classes) then return False.
+        If the target is a string type, then convert the string into a
+        concretized architecture. If it has no architecture and the root of the
+        DAG has an architecture, then use the root otherwise use the defaults
+        on the platform.
+        """
+        # ensure type safety for the architecture
+        if spec.architecture is None:
+            spec.architecture = spack.spec.ArchSpec()
+
+        if spec.architecture.concrete:
+            return False
+
+        # Get platform of nearest spec with a platform, including spec
+        # If spec has a platform, easy
+        if spec.architecture.platform:
+            new_plat = spack.platforms.by_name(spec.architecture.platform)
+        else:
+            # Else if anyone else has a platform, take the closest one
+            # Search up, then down, along build/link deps first
+            # Then any nearest. Algorithm from compilerspec search
+            platform_spec = find_spec(spec, lambda x: x.architecture and x.architecture.platform)
+            if platform_spec:
+                new_plat = spack.platforms.by_name(platform_spec.architecture.platform)
+            else:
+                # If no platform anywhere in this spec, grab the default
+                new_plat = spack.platforms.host()
+
+        # Get nearest spec with relevant platform and an os
+        # Generally, same algorithm as finding platform, except we only
+        # consider specs that have a platform
+        if spec.architecture.os:
+            new_os = spec.architecture.os
+        else:
+            new_os_spec = find_spec(
+                spec,
+                lambda x: (
+                    x.architecture
+                    and x.architecture.platform == str(new_plat)
+                    and x.architecture.os
+                ),
+            )
+            if new_os_spec:
+                new_os = new_os_spec.architecture.os
+            else:
+                new_os = new_plat.operating_system("default_os")
+
+        # Get the nearest spec with relevant platform and a target
+        # Generally, same algorithm as finding os
+        curr_target = None
+        if spec.architecture.target:
+            curr_target = spec.architecture.target
+        if spec.architecture.target and spec.architecture.target_concrete:
+            new_target = spec.architecture.target
+        else:
+            new_target_spec = find_spec(
+                spec,
+                lambda x: (
+                    x.architecture
+                    and x.architecture.platform == str(new_plat)
+                    and x.architecture.target
+                    and x.architecture.target != curr_target
+                ),
+            )
+            if new_target_spec:
+                if curr_target:
+                    # constrain one target by the other
+                    new_target_arch = spack.spec.ArchSpec(
+                        (None, None, new_target_spec.architecture.target)
+                    )
+                    curr_target_arch = spack.spec.ArchSpec((None, None, curr_target))
+                    curr_target_arch.constrain(new_target_arch)
+                    new_target = curr_target_arch.target
+                else:
+                    new_target = new_target_spec.architecture.target
+            else:
+                # To get default platform, consider package prefs
+                if PackagePrefs.has_preferred_targets(spec.name):
+                    new_target = self.target_from_package_preferences(spec)
+                else:
+                    new_target = new_plat.target("default_target")
+                if curr_target:
+                    # convert to ArchSpec to compare satisfaction
+                    new_target_arch = spack.spec.ArchSpec((None, None, str(new_target)))
+                    curr_target_arch = spack.spec.ArchSpec((None, None, str(curr_target)))
+
+                    if not new_target_arch.intersects(curr_target_arch):
+                        # new_target is an incorrect guess based on preferences
+                        # and/or default
+                        valid_target_ranges = str(curr_target).split(",")
+                        for target_range in valid_target_ranges:
+                            t_min, t_sep, t_max = target_range.partition(":")
+                            if not t_sep:
+                                new_target = t_min
+                                break
+                            elif t_max:
+                                new_target = t_max
+                                break
+                            elif t_min:
+                                # TODO: something better than picking first
+                                new_target = t_min
+                                break
+
+        # Construct new architecture, compute whether spec changed
+        arch_spec = (str(new_plat), str(new_os), str(new_target))
+        new_arch = spack.spec.ArchSpec(arch_spec)
+        spec_changed = new_arch != spec.architecture
+        spec.architecture = new_arch
+        return spec_changed
+
+    def target_from_package_preferences(self, spec):
+        """Returns the preferred target from the package preferences if
+        there's any.
+
+        Args:
+            spec: abstract spec to be concretized
+        """
+        target_prefs = PackagePrefs(spec.name, "target")
+        target_specs = [spack.spec.Spec("target=%s" % tname) for tname in archspec.cpu.TARGETS]
+
+        def tspec_filter(s):
+            # Filter target specs by whether the architecture
+            # family is the current machine type. This ensures
+            # we only consider x86_64 targets when on an
+            # x86_64 machine, etc. This may need to change to
+            # enable setting cross compiling as a default
+            target = archspec.cpu.TARGETS[str(s.architecture.target)]
+            arch_family_name = target.family.name
+            return arch_family_name == platform.machine()
+
+        # Sort filtered targets by package prefs
+        target_specs = list(filter(tspec_filter, target_specs))
+        target_specs.sort(key=target_prefs)
+        new_target = target_specs[0].architecture.target
+        return new_target
+
+    def concretize_variants(self, spec):
+        """If the spec already has variants filled in, return.  Otherwise, add
+        the user preferences from packages.yaml or the default variants from
+        the package specification.
+        """
+        changed = False
+        preferred_variants = PackagePrefs.preferred_variants(spec.name)
+        pkg_cls = spec.package_class
+        for name, entry in pkg_cls.variants.items():
+            variant, when = entry
+            var = spec.variants.get(name, None)
+            if var and "*" in var:
+                # remove variant wildcard before concretizing
+                # wildcard cannot be combined with other variables in a
+                # multivalue variant, a concrete variant cannot have the value
+                # wildcard, and a wildcard does not constrain a variant
+                spec.variants.pop(name)
+            if name not in spec.variants and any(spec.satisfies(w) for w in when):
+                changed = True
+                if name in preferred_variants:
+                    spec.variants[name] = preferred_variants.get(name)
+                else:
+                    spec.variants[name] = variant.make_default()
+            if name in spec.variants and not any(spec.satisfies(w) for w in when):
+                raise vt.InvalidVariantForSpecError(name, when, spec)
+
+        return changed
+
+    def concretize_compiler(self, spec):
+        """If the spec already has a compiler, we're done.  If not, then take
+        the compiler used for the nearest ancestor with a compiler
+        spec and use that.  If the ancestor's compiler is not
+        concrete, then used the preferred compiler as specified in
+        spackconfig.
+
+        Intuition: Use the spackconfig default if no package that depends on
+        this one has a strict compiler requirement.  Otherwise, try to
+        build with the compiler that will be used by libraries that
+        link to this one, to maximize compatibility.
+        """
+        # Pass on concretizing the compiler if the target or operating system
+        # is not yet determined
+        if not spec.architecture.concrete:
+            # We haven't changed, but other changes need to happen before we
+            # continue. `return True` here to force concretization to keep
+            # running.
+            return True
+
+        # Only use a matching compiler if it is of the proper style
+        # Takes advantage of the proper logic already existing in
+        # compiler_for_spec Should think whether this can be more
+        # efficient
+        def _proper_compiler_style(cspec, aspec):
+            compilers = spack.compilers.compilers_for_spec(cspec, arch_spec=aspec)
+            # If the spec passed as argument is concrete we want to check
+            # the versions match exactly
+            if (
+                cspec.concrete
+                and compilers
+                and cspec.version not in [c.version for c in compilers]
+            ):
+                return []
+
+            return compilers
+
+        if spec.compiler and spec.compiler.concrete:
+            if self.check_for_compiler_existence and not _proper_compiler_style(
+                spec.compiler, spec.architecture
+            ):
+                _compiler_concretization_failure(spec.compiler, spec.architecture)
+            return False
+
+        # Find another spec that has a compiler, or the root if none do
+        other_spec = spec if spec.compiler else find_spec(spec, lambda x: x.compiler, spec.root)
+        other_compiler = other_spec.compiler
+        assert other_spec
+
+        # Check if the compiler is already fully specified
+        if other_compiler and other_compiler.concrete:
+            if self.check_for_compiler_existence and not _proper_compiler_style(
+                other_compiler, spec.architecture
+            ):
+                _compiler_concretization_failure(other_compiler, spec.architecture)
+            spec.compiler = other_compiler
+            return True
+
+        if other_compiler:  # Another node has abstract compiler information
+            compiler_list = spack.compilers.find_specs_by_arch(other_compiler, spec.architecture)
+            if not compiler_list:
+                # We don't have a matching compiler installed
+                if not self.check_for_compiler_existence:
+                    # Concretize compiler spec versions as a package to build
+                    cpkg_spec = spack.compilers.pkg_spec_for_compiler(other_compiler)
+                    self.concretize_version(cpkg_spec)
+                    spec.compiler = spack.spec.CompilerSpec(
+                        other_compiler.name, cpkg_spec.versions
+                    )
+                    return True
+                else:
+                    # No compiler with a satisfactory spec was found
+                    raise UnavailableCompilerVersionError(other_compiler, spec.architecture)
+        else:
+            # We have no hints to go by, grab any compiler
+            compiler_list = spack.compilers.all_compiler_specs()
+            if not compiler_list:
+                # Spack has no compilers.
+                raise spack.compilers.NoCompilersError()
+
+        # By default, prefer later versions of compilers
+        compiler_list = sorted(compiler_list, key=lambda x: (x.name, x.version), reverse=True)
+        ppk = PackagePrefs(other_spec.name, "compiler")
+        matches = sorted(compiler_list, key=ppk)
+
+        # copy concrete version into other_compiler
+        try:
+            spec.compiler = next(
+                c for c in matches if _proper_compiler_style(c, spec.architecture)
+            ).copy()
+        except StopIteration:
+            # No compiler with a satisfactory spec has a suitable arch
+            _compiler_concretization_failure(other_compiler, spec.architecture)
+
+        assert spec.compiler.concrete
+        return True  # things changed.
+
+    def concretize_compiler_flags(self, spec):
+        """
+        The compiler flags are updated to match those of the spec whose
+        compiler is used, defaulting to no compiler flags in the spec.
+        Default specs set at the compiler level will still be added later.
+        """
+        # Pass on concretizing the compiler flags if the target or operating
+        # system is not set.
+        if not spec.architecture.concrete:
+            # We haven't changed, but other changes need to happen before we
+            # continue. `return True` here to force concretization to keep
+            # running.
+            return True
+
+        compiler_match = lambda other: (
+            spec.compiler == other.compiler and spec.architecture == other.architecture
+        )
+
+        ret = False
+        for flag in spack.spec.FlagMap.valid_compiler_flags():
+            if flag not in spec.compiler_flags:
+                spec.compiler_flags[flag] = list()
+            try:
+                nearest = next(
+                    p
+                    for p in spec.traverse(direction="parents")
+                    if (compiler_match(p) and (p is not spec) and flag in p.compiler_flags)
+                )
+                nearest_flags = nearest.compiler_flags.get(flag, [])
+                flags = spec.compiler_flags.get(flag, [])
+                if set(nearest_flags) - set(flags):
+                    spec.compiler_flags[flag] = list(llnl.util.lang.dedupe(nearest_flags + flags))
+                    ret = True
+            except StopIteration:
+                pass
+
+        # Include the compiler flag defaults from the config files
+        # This ensures that spack will detect conflicts that stem from a change
+        # in default compiler flags.
+        try:
+            compiler = spack.compilers.compiler_for_spec(spec.compiler, spec.architecture)
+        except spack.compilers.NoCompilerForSpecError:
+            if self.check_for_compiler_existence:
+                raise
+            return ret
+        for flag in compiler.flags:
+            config_flags = compiler.flags.get(flag, [])
+            flags = spec.compiler_flags.get(flag, [])
+            spec.compiler_flags[flag] = list(llnl.util.lang.dedupe(config_flags + flags))
+            if set(config_flags) - set(flags):
+                ret = True
+
+        return ret
+
+    def adjust_target(self, spec):
+        """Adjusts the target microarchitecture if the compiler is too old
+        to support the default one.
+
+        Args:
+            spec: spec to be concretized
+
+        Returns:
+            True if spec was modified, False otherwise
+        """
+        # To minimize the impact on performance this function will attempt
+        # to adjust the target only at the very first call once necessary
+        # information is set. It will just return False on subsequent calls.
+        # The way this is achieved is by initializing a generator and making
+        # this function return the next answer.
+        if not (spec.architecture and spec.architecture.concrete):
+            # Not ready, but keep going because we have work to do later
+            return True
+
+        def _make_only_one_call(spec):
+            yield self._adjust_target(spec)
+            while True:
+                yield False
+
+        if self._adjust_target_answer_generator is None:
+            self._adjust_target_answer_generator = _make_only_one_call(spec)
+
+        return next(self._adjust_target_answer_generator)
+
+    def _adjust_target(self, spec):
+        """Assumes that the architecture and the compiler have been
+        set already and checks if the current target microarchitecture
+        is the default and can be optimized by the compiler.
+
+        If not, downgrades the microarchitecture until a suitable one
+        is found. If none can be found raise an error.
+
+        Args:
+            spec: spec to be concretized
+
+        Returns:
+            True if any modification happened, False otherwise
+        """
+        import archspec.cpu
+
+        # Try to adjust the target only if it is the default
+        # target for this platform
+        current_target = spec.architecture.target
+        current_platform = spack.platforms.by_name(spec.architecture.platform)
+
+        default_target = current_platform.target("default_target")
+        if PackagePrefs.has_preferred_targets(spec.name):
+            default_target = self.target_from_package_preferences(spec)
+
+        if current_target != default_target or (
+            self.abstract_spec
+            and self.abstract_spec.architecture
+            and self.abstract_spec.architecture.concrete
+        ):
+            return False
+
+        try:
+            current_target.optimization_flags(spec.compiler)
+        except archspec.cpu.UnsupportedMicroarchitecture:
+            microarchitecture = current_target.microarchitecture
+            for ancestor in microarchitecture.ancestors:
+                candidate = None
+                try:
+                    candidate = spack.target.Target(ancestor)
+                    candidate.optimization_flags(spec.compiler)
+                except archspec.cpu.UnsupportedMicroarchitecture:
+                    continue
+
+                if candidate is not None:
+                    msg = (
+                        "{0.name}@{0.version} cannot build optimized "
+                        'binaries for "{1}". Using best target possible: '
+                        '"{2}"'
+                    )
+                    msg = msg.format(spec.compiler, current_target, candidate)
+                    tty.warn(msg)
+                    spec.architecture.target = candidate
+                    return True
+            else:
+                raise
+
+        return False
 
 
 @contextmanager
@@ -81,6 +719,19 @@ def find_spec(spec, condition, default=None):
     return default  # Nothing matched the condition; return default.
 
 
+def _compiler_concretization_failure(compiler_spec, arch):
+    # Distinguish between the case that there are compilers for
+    # the arch but not with the given compiler spec and the case that
+    # there are no compilers for the arch at all
+    if not spack.compilers.compilers_for_arch(arch):
+        available_os_targets = set(
+            (c.operating_system, c.target) for c in spack.compilers.all_compilers()
+        )
+        raise NoCompilersForArchError(arch, available_os_targets)
+    else:
+        raise UnavailableCompilerVersionError(compiler_spec, arch)
+
+
 def concretize_specs_together(*abstract_specs, **kwargs):
     """Given a number of specs as input, tries to concretize them together.
 
@@ -93,6 +744,12 @@ def concretize_specs_together(*abstract_specs, **kwargs):
     Returns:
         List of concretized specs
     """
+    if spack.config.get("config:concretizer", "clingo") == "original":
+        return _concretize_specs_together_original(*abstract_specs, **kwargs)
+    return _concretize_specs_together_new(*abstract_specs, **kwargs)
+
+
+def _concretize_specs_together_new(*abstract_specs, **kwargs):
     import spack.solver.asp
 
     allow_deprecated = spack.config.get("config:deprecated", False)
@@ -103,6 +760,51 @@ def concretize_specs_together(*abstract_specs, **kwargs):
     return [s.copy() for s in result.specs]
 
 
+def _concretize_specs_together_original(*abstract_specs, **kwargs):
+    abstract_specs = [spack.spec.Spec(s) for s in abstract_specs]
+    tmpdir = tempfile.mkdtemp()
+    builder = spack.repo.MockRepositoryBuilder(tmpdir)
+    # Split recursive specs, as it seems the concretizer has issue
+    # respecting conditions on dependents expressed like
+    # depends_on('foo ^bar@1.0'), see issue #11160
+    split_specs = [
+        dep.copy(deps=False) for spec1 in abstract_specs for dep in spec1.traverse(root=True)
+    ]
+    builder.add_package(
+        "concretizationroot", dependencies=[(str(x), None, None) for x in split_specs]
+    )
+
+    with spack.repo.use_repositories(builder.root, override=False):
+        # Spec from a helper package that depends on all the abstract_specs
+        concretization_root = spack.spec.Spec("concretizationroot")
+        concretization_root.concretize(tests=kwargs.get("tests", False))
+        # Retrieve the direct dependencies
+        concrete_specs = [concretization_root[spec.name].copy() for spec in abstract_specs]
+
+    return concrete_specs
+
+
+class NoCompilersForArchError(spack.error.SpackError):
+    def __init__(self, arch, available_os_targets):
+        err_msg = (
+            "No compilers found"
+            " for operating system %s and target %s."
+            "\nIf previous installations have succeeded, the"
+            " operating system may have been updated." % (arch.os, arch.target)
+        )
+
+        available_os_target_strs = list()
+        for operating_system, t in available_os_targets:
+            os_target_str = "%s-%s" % (operating_system, t) if t else operating_system
+            available_os_target_strs.append(os_target_str)
+        err_msg += (
+            "\nCompilers are defined for the following"
+            " operating systems and targets:\n\t" + "\n\t".join(available_os_target_strs)
+        )
+
+        super().__init__(err_msg, "Run 'spack compiler find' to add compilers.")
+
+
 class UnavailableCompilerVersionError(spack.error.SpackError):
     """Raised when there is no available compiler that satisfies a
     compiler spec."""
@@ -118,3 +820,37 @@ def __init__(self, compiler_spec, arch=None):
             "'spack compilers' to see which compilers are already recognized"
             " by spack.",
         )
+
+
+class NoValidVersionError(spack.error.SpackError):
+    """Raised when there is no way to have a concrete version for a
+    particular spec."""
+
+    def __init__(self, spec):
+        super().__init__(
+            "There are no valid versions for %s that match '%s'" % (spec.name, spec.versions)
+        )
+
+
+class InsufficientArchitectureInfoError(spack.error.SpackError):
+    """Raised when details on architecture cannot be collected from the
+    system"""
+
+    def __init__(self, spec, archs):
+        super().__init__(
+            "Cannot determine necessary architecture information for '%s': %s"
+            % (spec.name, str(archs))
+        )
+
+
+class NoBuildError(spack.error.SpecError):
+    """Raised when a package is configured with the buildable option False, but
+    no satisfactory external versions can be found
+    """
+
+    def __init__(self, spec):
+        msg = (
+            "The spec\n    '%s'\n    is configured as not buildable, "
+            "and no matching external installs were found"
+        )
+        super().__init__(msg % spec)

lib/spack/spack/config.py

@@ -99,6 +99,7 @@
         "dirty": False,
         "build_jobs": min(16, cpus_available()),
         "build_stage": "$tempdir/spack-stage",
+        "concretizer": "clingo",
         "license_dir": spack.paths.default_license_dir,
     }
 }
@@ -1090,7 +1091,7 @@ def validate(
 
 
 def read_config_file(
-    path: str, schema: Optional[YamlConfigDict] = None
+    filename: str, schema: Optional[YamlConfigDict] = None
 ) -> Optional[YamlConfigDict]:
     """Read a YAML configuration file.
 
@@ -1100,9 +1101,21 @@ def read_config_file(
     # to preserve flexibility in calling convention (don't need to provide
     # schema when it's not necessary) while allowing us to validate against a
     # known schema when the top-level key could be incorrect.
+
+    if not os.path.exists(filename):
+        # Ignore nonexistent files.
+        tty.debug(f"Skipping nonexistent config path {filename}", level=3)
+        return None
+
+    elif not os.path.isfile(filename):
+        raise ConfigFileError(f"Invalid configuration. {filename} exists but is not a file.")
+
+    elif not os.access(filename, os.R_OK):
+        raise ConfigFileError(f"Config file is not readable: {filename}")
+
     try:
-        with open(path) as f:
-            tty.debug(f"Reading config from file {path}")
+        tty.debug(f"Reading config from file {filename}")
+        with open(filename) as f:
             data = syaml.load_config(f)
 
         if data:
@@ -1113,20 +1126,15 @@ def read_config_file(
 
         return data
 
-    except FileNotFoundError:
-        # Ignore nonexistent files.
-        tty.debug(f"Skipping nonexistent config path {path}", level=3)
-        return None
-
-    except OSError as e:
-        raise ConfigFileError(f"Path is not a file or is not readable: {path}: {str(e)}") from e
-
-    except StopIteration as e:
-        raise ConfigFileError(f"Config file is empty or is not a valid YAML dict: {path}") from e
+    except StopIteration:
+        raise ConfigFileError(f"Config file is empty or is not a valid YAML dict: {filename}")
 
     except syaml.SpackYAMLError as e:
         raise ConfigFileError(str(e)) from e
 
+    except OSError as e:
+        raise ConfigFileError(f"Error reading configuration file {filename}: {str(e)}") from e
+
 
 def _override(string: str) -> bool:
     """Test if a spack YAML string is an override.

lib/spack/spack/detection/common.py

@@ -45,9 +45,7 @@ def __reduce__(self):
     def restore(
         spec_str: str, prefix: str, extra_attributes: Optional[Dict[str, str]]
     ) -> "DetectedPackage":
-        spec = spack.spec.Spec.from_detection(
-            spec_str=spec_str, external_path=prefix, extra_attributes=extra_attributes
-        )
+        spec = spack.spec.Spec.from_detection(spec_str=spec_str, extra_attributes=extra_attributes)
         return DetectedPackage(spec=spec, prefix=prefix)
 
 
@@ -138,10 +136,10 @@ def path_to_dict(search_paths: List[str]):
     # entry overrides later entries
     for search_path in reversed(search_paths):
         try:
-            with os.scandir(search_path) as entries:
-                path_to_lib.update(
-                    {entry.path: entry.name for entry in entries if entry.is_file()}
-                )
+            for lib in os.listdir(search_path):
+                lib_path = os.path.join(search_path, lib)
+                if llnl.util.filesystem.is_readable_file(lib_path):
+                    path_to_lib[lib_path] = lib
         except OSError as e:
             msg = f"cannot scan '{search_path}' for external software: {str(e)}"
             llnl.util.tty.debug(msg)
@@ -241,7 +239,7 @@ def update_configuration(
         external_entries = pkg_config.get("externals", [])
         assert not isinstance(external_entries, bool), "unexpected value for external entry"
 
-        all_new_specs.extend([x.spec for x in new_entries])
+        all_new_specs.extend([spack.spec.Spec(x["spec"]) for x in external_entries])
         if buildable is False:
             pkg_config["buildable"] = False
         pkg_to_cfg[package_name] = pkg_config

lib/spack/spack/detection/path.py

@@ -12,7 +12,7 @@
 import re
 import sys
 import warnings
-from typing import Dict, Iterable, List, Optional, Set, Tuple, Type
+from typing import Dict, List, Optional, Set, Tuple, Type
 
 import llnl.util.filesystem
 import llnl.util.lang
@@ -62,7 +62,7 @@ def common_windows_package_paths(pkg_cls=None) -> List[str]:
 
 def file_identifier(path):
     s = os.stat(path)
-    return s.st_dev, s.st_ino
+    return (s.st_dev, s.st_ino)
 
 
 def executables_in_path(path_hints: List[str]) -> Dict[str, str]:
@@ -80,8 +80,6 @@ def executables_in_path(path_hints: List[str]) -> Dict[str, str]:
             constructed based on the PATH environment variable.
     """
     search_paths = llnl.util.filesystem.search_paths_for_executables(*path_hints)
-    # Make use we don't doubly list /usr/lib and /lib etc
-    search_paths = list(llnl.util.lang.dedupe(search_paths, key=file_identifier))
     return path_to_dict(search_paths)
 
 
@@ -189,7 +187,7 @@ def libraries_in_windows_paths(path_hints: Optional[List[str]] = None) -> Dict[s
     return path_to_dict(search_paths)
 
 
-def _group_by_prefix(paths: List[str]) -> Dict[str, Set[str]]:
+def _group_by_prefix(paths: Set[str]) -> Dict[str, Set[str]]:
     groups = collections.defaultdict(set)
     for p in paths:
         groups[os.path.dirname(p)].add(p)
@@ -245,9 +243,7 @@ def detect_specs(
             return []
 
         result = []
-        for candidate_path, items_in_prefix in _group_by_prefix(
-            llnl.util.lang.dedupe(paths)
-        ).items():
+        for candidate_path, items_in_prefix in sorted(_group_by_prefix(set(paths)).items()):
             # TODO: multiple instances of a package can live in the same
             # prefix, and a package implementation can return multiple specs
             # for one prefix, but without additional details (e.g. about the
@@ -303,17 +299,19 @@ def detect_specs(
         return result
 
     def find(
-        self, *, pkg_name: str, repository, initial_guess: Optional[List[str]] = None
+        self, *, pkg_name: str, initial_guess: Optional[List[str]] = None
     ) -> List[DetectedPackage]:
         """For a given package, returns a list of detected specs.
 
         Args:
             pkg_name: package being detected
-            repository: repository to retrieve the package
-            initial_guess: initial list of paths to search from the caller if None, default paths
-                are searched. If this is an empty list, nothing will be searched.
+            initial_guess: initial list of paths to search from the caller
+                           if None, default paths are searched. If this
+                           is an empty list, nothing will be searched.
         """
-        pkg_cls = repository.get_pkg_class(pkg_name)
+        import spack.repo
+
+        pkg_cls = spack.repo.PATH.get_pkg_class(pkg_name)
         patterns = self.search_patterns(pkg=pkg_cls)
         if not patterns:
             return []
@@ -337,10 +335,13 @@ def search_patterns(self, *, pkg: Type["spack.package_base.PackageBase"]) -> Lis
 
     def candidate_files(self, *, patterns: List[str], paths: List[str]) -> List[str]:
         executables_by_path = executables_in_path(path_hints=paths)
-        joined_pattern = re.compile(r"|".join(patterns))
-        result = [path for path, exe in executables_by_path.items() if joined_pattern.search(exe)]
-        result.sort()
-        return result
+        patterns = [re.compile(x) for x in patterns]
+        result = []
+        for compiled_re in patterns:
+            for path, exe in executables_by_path.items():
+                if compiled_re.search(exe):
+                    result.append(path)
+        return list(sorted(set(result)))
 
     def prefix_from_path(self, *, path: str) -> str:
         result = executable_prefix(path)
@@ -384,7 +385,7 @@ def prefix_from_path(self, *, path: str) -> str:
 
 
 def by_path(
-    packages_to_search: Iterable[str],
+    packages_to_search: List[str],
     *,
     path_hints: Optional[List[str]] = None,
     max_workers: Optional[int] = None,
@@ -398,28 +399,19 @@ def by_path(
         path_hints: initial list of paths to be searched
         max_workers: maximum number of workers to search for packages in parallel
     """
-    import spack.repo
-
     # TODO: Packages should be able to define both .libraries and .executables in the future
     # TODO: determine_spec_details should get all relevant libraries and executables in one call
     executables_finder, libraries_finder = ExecutablesFinder(), LibrariesFinder()
     detected_specs_by_package: Dict[str, Tuple[concurrent.futures.Future, ...]] = {}
 
     result = collections.defaultdict(list)
-    repository = spack.repo.PATH.ensure_unwrapped()
     with concurrent.futures.ProcessPoolExecutor(max_workers=max_workers) as executor:
         for pkg in packages_to_search:
             executable_future = executor.submit(
-                executables_finder.find,
-                pkg_name=pkg,
-                initial_guess=path_hints,
-                repository=repository,
+                executables_finder.find, pkg_name=pkg, initial_guess=path_hints
             )
             library_future = executor.submit(
-                libraries_finder.find,
-                pkg_name=pkg,
-                initial_guess=path_hints,
-                repository=repository,
+                libraries_finder.find, pkg_name=pkg, initial_guess=path_hints
             )
             detected_specs_by_package[pkg] = executable_future, library_future
 

lib/spack/spack/detection/test.py

@@ -104,9 +104,7 @@ def _create_executable_scripts(self, mock_executables: MockExecutables) -> List[
     @property
     def expected_specs(self) -> List[spack.spec.Spec]:
         return [
-            spack.spec.Spec.from_detection(
-                item.spec, external_path=self.tmpdir.name, extra_attributes=item.extra_attributes
-            )
+            spack.spec.Spec.from_detection(item.spec, extra_attributes=item.extra_attributes)
             for item in self.test.results
         ]
 

lib/spack/spack/directives.py

@@ -32,9 +32,10 @@ class OpenMpi(Package):
 """
 import collections
 import collections.abc
+import functools
 import os.path
 import re
-from typing import TYPE_CHECKING, Any, Callable, List, Optional, Tuple, Union
+from typing import TYPE_CHECKING, Any, Callable, List, Optional, Set, Tuple, Union
 
 import llnl.util.lang
 import llnl.util.tty.color
@@ -47,7 +48,6 @@ class OpenMpi(Package):
 import spack.util.crypto
 import spack.variant
 from spack.dependency import Dependency
-from spack.directives_meta import DirectiveError, DirectiveMeta
 from spack.fetch_strategy import from_kwargs
 from spack.resource import Resource
 from spack.version import (
@@ -80,6 +80,22 @@ class OpenMpi(Package):
     "redistribute",
 ]
 
+#: These are variant names used by Spack internally; packages can't use them
+reserved_names = [
+    "arch",
+    "architecture",
+    "dev_path",
+    "namespace",
+    "operating_system",
+    "os",
+    "patches",
+    "platform",
+    "target",
+]
+
+#: Names of possible directives. This list is mostly populated using the @directive decorator.
+#: Some directives leverage others and in that case are not automatically added.
+directive_names = ["build_system"]
 
 _patch_order_index = 0
 
@@ -139,6 +155,219 @@ def _make_when_spec(value: WhenType) -> Optional["spack.spec.Spec"]:
     return spack.spec.Spec(value)
 
 
+class DirectiveMeta(type):
+    """Flushes the directives that were temporarily stored in the staging
+    area into the package.
+    """
+
+    # Set of all known directives
+    _directive_dict_names: Set[str] = set()
+    _directives_to_be_executed: List[str] = []
+    _when_constraints_from_context: List[str] = []
+    _default_args: List[dict] = []
+
+    def __new__(cls, name, bases, attr_dict):
+        # Initialize the attribute containing the list of directives
+        # to be executed. Here we go reversed because we want to execute
+        # commands:
+        # 1. in the order they were defined
+        # 2. following the MRO
+        attr_dict["_directives_to_be_executed"] = []
+        for base in reversed(bases):
+            try:
+                directive_from_base = base._directives_to_be_executed
+                attr_dict["_directives_to_be_executed"].extend(directive_from_base)
+            except AttributeError:
+                # The base class didn't have the required attribute.
+                # Continue searching
+                pass
+
+        # De-duplicates directives from base classes
+        attr_dict["_directives_to_be_executed"] = [
+            x for x in llnl.util.lang.dedupe(attr_dict["_directives_to_be_executed"])
+        ]
+
+        # Move things to be executed from module scope (where they
+        # are collected first) to class scope
+        if DirectiveMeta._directives_to_be_executed:
+            attr_dict["_directives_to_be_executed"].extend(
+                DirectiveMeta._directives_to_be_executed
+            )
+            DirectiveMeta._directives_to_be_executed = []
+
+        return super(DirectiveMeta, cls).__new__(cls, name, bases, attr_dict)
+
+    def __init__(cls, name, bases, attr_dict):
+        # The instance is being initialized: if it is a package we must ensure
+        # that the directives are called to set it up.
+
+        if "spack.pkg" in cls.__module__:
+            # Ensure the presence of the dictionaries associated with the directives.
+            # All dictionaries are defaultdicts that create lists for missing keys.
+            for d in DirectiveMeta._directive_dict_names:
+                setattr(cls, d, {})
+
+            # Lazily execute directives
+            for directive in cls._directives_to_be_executed:
+                directive(cls)
+
+            # Ignore any directives executed *within* top-level
+            # directives by clearing out the queue they're appended to
+            DirectiveMeta._directives_to_be_executed = []
+
+        super(DirectiveMeta, cls).__init__(name, bases, attr_dict)
+
+    @staticmethod
+    def push_to_context(when_spec):
+        """Add a spec to the context constraints."""
+        DirectiveMeta._when_constraints_from_context.append(when_spec)
+
+    @staticmethod
+    def pop_from_context():
+        """Pop the last constraint from the context"""
+        return DirectiveMeta._when_constraints_from_context.pop()
+
+    @staticmethod
+    def push_default_args(default_args):
+        """Push default arguments"""
+        DirectiveMeta._default_args.append(default_args)
+
+    @staticmethod
+    def pop_default_args():
+        """Pop default arguments"""
+        return DirectiveMeta._default_args.pop()
+
+    @staticmethod
+    def directive(dicts=None):
+        """Decorator for Spack directives.
+
+        Spack directives allow you to modify a package while it is being
+        defined, e.g. to add version or dependency information.  Directives
+        are one of the key pieces of Spack's package "language", which is
+        embedded in python.
+
+        Here's an example directive:
+
+        .. code-block:: python
+
+            @directive(dicts='versions')
+            version(pkg, ...):
+                ...
+
+        This directive allows you write:
+
+        .. code-block:: python
+
+            class Foo(Package):
+                version(...)
+
+        The ``@directive`` decorator handles a couple things for you:
+
+          1. Adds the class scope (pkg) as an initial parameter when
+             called, like a class method would.  This allows you to modify
+             a package from within a directive, while the package is still
+             being defined.
+
+          2. It automatically adds a dictionary called "versions" to the
+             package so that you can refer to pkg.versions.
+
+        The ``(dicts='versions')`` part ensures that ALL packages in Spack
+        will have a ``versions`` attribute after they're constructed, and
+        that if no directive actually modified it, it will just be an
+        empty dict.
+
+        This is just a modular way to add storage attributes to the
+        Package class, and it's how Spack gets information from the
+        packages to the core.
+        """
+        global directive_names
+
+        if isinstance(dicts, str):
+            dicts = (dicts,)
+
+        if not isinstance(dicts, collections.abc.Sequence):
+            message = "dicts arg must be list, tuple, or string. Found {0}"
+            raise TypeError(message.format(type(dicts)))
+
+        # Add the dictionary names if not already there
+        DirectiveMeta._directive_dict_names |= set(dicts)
+
+        # This decorator just returns the directive functions
+        def _decorator(decorated_function):
+            directive_names.append(decorated_function.__name__)
+
+            @functools.wraps(decorated_function)
+            def _wrapper(*args, **_kwargs):
+                # First merge default args with kwargs
+                kwargs = dict()
+                for default_args in DirectiveMeta._default_args:
+                    kwargs.update(default_args)
+                kwargs.update(_kwargs)
+
+                # Inject when arguments from the context
+                if DirectiveMeta._when_constraints_from_context:
+                    # Check that directives not yet supporting the when= argument
+                    # are not used inside the context manager
+                    if decorated_function.__name__ == "version":
+                        msg = (
+                            'directive "{0}" cannot be used within a "when"'
+                            ' context since it does not support a "when=" '
+                            "argument"
+                        )
+                        msg = msg.format(decorated_function.__name__)
+                        raise DirectiveError(msg)
+
+                    when_constraints = [
+                        spack.spec.Spec(x) for x in DirectiveMeta._when_constraints_from_context
+                    ]
+                    if kwargs.get("when"):
+                        when_constraints.append(spack.spec.Spec(kwargs["when"]))
+                    when_spec = spack.spec.merge_abstract_anonymous_specs(*when_constraints)
+
+                    kwargs["when"] = when_spec
+
+                # If any of the arguments are executors returned by a
+                # directive passed as an argument, don't execute them
+                # lazily. Instead, let the called directive handle them.
+                # This allows nested directive calls in packages.  The
+                # caller can return the directive if it should be queued.
+                def remove_directives(arg):
+                    directives = DirectiveMeta._directives_to_be_executed
+                    if isinstance(arg, (list, tuple)):
+                        # Descend into args that are lists or tuples
+                        for a in arg:
+                            remove_directives(a)
+                    else:
+                        # Remove directives args from the exec queue
+                        remove = next((d for d in directives if d is arg), None)
+                        if remove is not None:
+                            directives.remove(remove)
+
+                # Nasty, but it's the best way I can think of to avoid
+                # side effects if directive results are passed as args
+                remove_directives(args)
+                remove_directives(list(kwargs.values()))
+
+                # A directive returns either something that is callable on a
+                # package or a sequence of them
+                result = decorated_function(*args, **kwargs)
+
+                # ...so if it is not a sequence make it so
+                values = result
+                if not isinstance(values, collections.abc.Sequence):
+                    values = (values,)
+
+                DirectiveMeta._directives_to_be_executed.extend(values)
+
+                # wrapped function returns same result as original so
+                # that we can nest directives
+                return result
+
+            return _wrapper
+
+        return _decorator
+
+
 SubmoduleCallback = Callable[["spack.package_base.PackageBase"], Union[str, List[str], bool]]
 directive = DirectiveMeta.directive
 
@@ -617,7 +846,7 @@ def format_error(msg, pkg):
         msg += " @*r{{[{0}, variant '{1}']}}"
         return llnl.util.tty.color.colorize(msg.format(pkg.name, name))
 
-    if name in spack.variant.reserved_names:
+    if name in reserved_names:
 
         def _raise_reserved_name(pkg):
             msg = "The name '%s' is reserved by Spack" % name
@@ -881,6 +1110,10 @@ def _execute_languages(pkg: "spack.package_base.PackageBase"):
     return _execute_languages
 
 
+class DirectiveError(spack.error.SpackError):
+    """This is raised when something is wrong with a package directive."""
+
+
 class DependencyError(DirectiveError):
     """This is raised when a dependency specification is invalid."""
 

lib/spack/spack/directives_meta.py

@@ -1,234 +0,0 @@
-# Copyright 2013-2024 Lawrence Livermore National Security, LLC and other
-# Spack Project Developers. See the top-level COPYRIGHT file for details.
-#
-# SPDX-License-Identifier: (Apache-2.0 OR MIT)
-
-import collections.abc
-import functools
-from typing import List, Set
-
-import llnl.util.lang
-
-import spack.error
-import spack.spec
-
-#: Names of possible directives. This list is mostly populated using the @directive decorator.
-#: Some directives leverage others and in that case are not automatically added.
-directive_names = ["build_system"]
-
-
-class DirectiveMeta(type):
-    """Flushes the directives that were temporarily stored in the staging
-    area into the package.
-    """
-
-    # Set of all known directives
-    _directive_dict_names: Set[str] = set()
-    _directives_to_be_executed: List[str] = []
-    _when_constraints_from_context: List[str] = []
-    _default_args: List[dict] = []
-
-    def __new__(cls, name, bases, attr_dict):
-        # Initialize the attribute containing the list of directives
-        # to be executed. Here we go reversed because we want to execute
-        # commands:
-        # 1. in the order they were defined
-        # 2. following the MRO
-        attr_dict["_directives_to_be_executed"] = []
-        for base in reversed(bases):
-            try:
-                directive_from_base = base._directives_to_be_executed
-                attr_dict["_directives_to_be_executed"].extend(directive_from_base)
-            except AttributeError:
-                # The base class didn't have the required attribute.
-                # Continue searching
-                pass
-
-        # De-duplicates directives from base classes
-        attr_dict["_directives_to_be_executed"] = [
-            x for x in llnl.util.lang.dedupe(attr_dict["_directives_to_be_executed"])
-        ]
-
-        # Move things to be executed from module scope (where they
-        # are collected first) to class scope
-        if DirectiveMeta._directives_to_be_executed:
-            attr_dict["_directives_to_be_executed"].extend(
-                DirectiveMeta._directives_to_be_executed
-            )
-            DirectiveMeta._directives_to_be_executed = []
-
-        return super(DirectiveMeta, cls).__new__(cls, name, bases, attr_dict)
-
-    def __init__(cls, name, bases, attr_dict):
-        # The instance is being initialized: if it is a package we must ensure
-        # that the directives are called to set it up.
-
-        if "spack.pkg" in cls.__module__:
-            # Ensure the presence of the dictionaries associated with the directives.
-            # All dictionaries are defaultdicts that create lists for missing keys.
-            for d in DirectiveMeta._directive_dict_names:
-                setattr(cls, d, {})
-
-            # Lazily execute directives
-            for directive in cls._directives_to_be_executed:
-                directive(cls)
-
-            # Ignore any directives executed *within* top-level
-            # directives by clearing out the queue they're appended to
-            DirectiveMeta._directives_to_be_executed = []
-
-        super(DirectiveMeta, cls).__init__(name, bases, attr_dict)
-
-    @staticmethod
-    def push_to_context(when_spec):
-        """Add a spec to the context constraints."""
-        DirectiveMeta._when_constraints_from_context.append(when_spec)
-
-    @staticmethod
-    def pop_from_context():
-        """Pop the last constraint from the context"""
-        return DirectiveMeta._when_constraints_from_context.pop()
-
-    @staticmethod
-    def push_default_args(default_args):
-        """Push default arguments"""
-        DirectiveMeta._default_args.append(default_args)
-
-    @staticmethod
-    def pop_default_args():
-        """Pop default arguments"""
-        return DirectiveMeta._default_args.pop()
-
-    @staticmethod
-    def directive(dicts=None):
-        """Decorator for Spack directives.
-
-        Spack directives allow you to modify a package while it is being
-        defined, e.g. to add version or dependency information.  Directives
-        are one of the key pieces of Spack's package "language", which is
-        embedded in python.
-
-        Here's an example directive:
-
-        .. code-block:: python
-
-            @directive(dicts='versions')
-            version(pkg, ...):
-                ...
-
-        This directive allows you write:
-
-        .. code-block:: python
-
-            class Foo(Package):
-                version(...)
-
-        The ``@directive`` decorator handles a couple things for you:
-
-          1. Adds the class scope (pkg) as an initial parameter when
-             called, like a class method would.  This allows you to modify
-             a package from within a directive, while the package is still
-             being defined.
-
-          2. It automatically adds a dictionary called "versions" to the
-             package so that you can refer to pkg.versions.
-
-        The ``(dicts='versions')`` part ensures that ALL packages in Spack
-        will have a ``versions`` attribute after they're constructed, and
-        that if no directive actually modified it, it will just be an
-        empty dict.
-
-        This is just a modular way to add storage attributes to the
-        Package class, and it's how Spack gets information from the
-        packages to the core.
-        """
-        global directive_names
-
-        if isinstance(dicts, str):
-            dicts = (dicts,)
-
-        if not isinstance(dicts, collections.abc.Sequence):
-            message = "dicts arg must be list, tuple, or string. Found {0}"
-            raise TypeError(message.format(type(dicts)))
-
-        # Add the dictionary names if not already there
-        DirectiveMeta._directive_dict_names |= set(dicts)
-
-        # This decorator just returns the directive functions
-        def _decorator(decorated_function):
-            directive_names.append(decorated_function.__name__)
-
-            @functools.wraps(decorated_function)
-            def _wrapper(*args, **_kwargs):
-                # First merge default args with kwargs
-                kwargs = dict()
-                for default_args in DirectiveMeta._default_args:
-                    kwargs.update(default_args)
-                kwargs.update(_kwargs)
-
-                # Inject when arguments from the context
-                if DirectiveMeta._when_constraints_from_context:
-                    # Check that directives not yet supporting the when= argument
-                    # are not used inside the context manager
-                    if decorated_function.__name__ == "version":
-                        msg = (
-                            'directive "{0}" cannot be used within a "when"'
-                            ' context since it does not support a "when=" '
-                            "argument"
-                        )
-                        msg = msg.format(decorated_function.__name__)
-                        raise DirectiveError(msg)
-
-                    when_constraints = [
-                        spack.spec.Spec(x) for x in DirectiveMeta._when_constraints_from_context
-                    ]
-                    if kwargs.get("when"):
-                        when_constraints.append(spack.spec.Spec(kwargs["when"]))
-                    when_spec = spack.spec.merge_abstract_anonymous_specs(*when_constraints)
-
-                    kwargs["when"] = when_spec
-
-                # If any of the arguments are executors returned by a
-                # directive passed as an argument, don't execute them
-                # lazily. Instead, let the called directive handle them.
-                # This allows nested directive calls in packages.  The
-                # caller can return the directive if it should be queued.
-                def remove_directives(arg):
-                    directives = DirectiveMeta._directives_to_be_executed
-                    if isinstance(arg, (list, tuple)):
-                        # Descend into args that are lists or tuples
-                        for a in arg:
-                            remove_directives(a)
-                    else:
-                        # Remove directives args from the exec queue
-                        remove = next((d for d in directives if d is arg), None)
-                        if remove is not None:
-                            directives.remove(remove)
-
-                # Nasty, but it's the best way I can think of to avoid
-                # side effects if directive results are passed as args
-                remove_directives(args)
-                remove_directives(list(kwargs.values()))
-
-                # A directive returns either something that is callable on a
-                # package or a sequence of them
-                result = decorated_function(*args, **kwargs)
-
-                # ...so if it is not a sequence make it so
-                values = result
-                if not isinstance(values, collections.abc.Sequence):
-                    values = (values,)
-
-                DirectiveMeta._directives_to_be_executed.extend(values)
-
-                # wrapped function returns same result as original so
-                # that we can nest directives
-                return result
-
-            return _wrapper
-
-        return _decorator
-
-
-class DirectiveError(spack.error.SpackError):
-    """This is raised when something is wrong with a package directive."""

lib/spack/spack/environment/environment.py

@@ -1214,6 +1214,7 @@ def scope_name(self):
     def include_concrete_envs(self):
         """Copy and save the included envs' specs internally"""
 
+        lockfile_meta = None
         root_hash_seen = set()
         concrete_hash_seen = set()
         self.included_concrete_spec_data = {}
@@ -1224,26 +1225,37 @@ def include_concrete_envs(self):
                 raise SpackEnvironmentError(f"Unable to find env at {env_path}")
 
             env = Environment(env_path)
-            self.included_concrete_spec_data[env_path] = {"roots": [], "concrete_specs": {}}
+
+            with open(env.lock_path) as f:
+                lockfile_as_dict = env._read_lockfile(f)
+
+            # Lockfile_meta must match each env and use at least format version 5
+            if lockfile_meta is None:
+                lockfile_meta = lockfile_as_dict["_meta"]
+            elif lockfile_meta != lockfile_as_dict["_meta"]:
+                raise SpackEnvironmentError("All lockfile _meta values must match")
+            elif lockfile_meta["lockfile-version"] < 5:
+                raise SpackEnvironmentError("The lockfile format must be at version 5 or higher")
 
             # Copy unique root specs from env
-            for root_dict in env._concrete_roots_dict():
+            self.included_concrete_spec_data[env_path] = {"roots": []}
+            for root_dict in lockfile_as_dict["roots"]:
                 if root_dict["hash"] not in root_hash_seen:
                     self.included_concrete_spec_data[env_path]["roots"].append(root_dict)
                     root_hash_seen.add(root_dict["hash"])
 
             # Copy unique concrete specs from env
-            for dag_hash, spec_details in env._concrete_specs_dict().items():
-                if dag_hash not in concrete_hash_seen:
-                    self.included_concrete_spec_data[env_path]["concrete_specs"].update(
-                        {dag_hash: spec_details}
+            for concrete_spec in lockfile_as_dict["concrete_specs"]:
+                if concrete_spec not in concrete_hash_seen:
+                    self.included_concrete_spec_data[env_path].update(
+                        {"concrete_specs": lockfile_as_dict["concrete_specs"]}
                     )
-                    concrete_hash_seen.add(dag_hash)
+                    concrete_hash_seen.add(concrete_spec)
 
-            # Copy transitive include data
-            transitive = env.included_concrete_spec_data
-            if transitive:
-                self.included_concrete_spec_data[env_path]["include_concrete"] = transitive
+            if "include_concrete" in lockfile_as_dict.keys():
+                self.included_concrete_spec_data[env_path]["include_concrete"] = lockfile_as_dict[
+                    "include_concrete"
+                ]
 
         self._read_lockfile_dict(self._to_lockfile_dict())
         self.write()
@@ -1632,8 +1644,9 @@ def _concretize_separately(self, tests=False):
                 i += 1
 
         # Ensure we don't try to bootstrap clingo in parallel
-        with spack.bootstrap.ensure_bootstrap_configuration():
-            spack.bootstrap.ensure_clingo_importable_or_raise()
+        if spack.config.get("config:concretizer", "clingo") == "clingo":
+            with spack.bootstrap.ensure_bootstrap_configuration():
+                spack.bootstrap.ensure_clingo_importable_or_raise()
 
         # Ensure all the indexes have been built or updated, since
         # otherwise the processes in the pool may timeout on waiting
@@ -1644,7 +1657,7 @@ def _concretize_separately(self, tests=False):
 
         # Ensure we have compilers in compilers.yaml to avoid that
         # processes try to write the config file in parallel
-        _ = spack.compilers.all_compilers_config(spack.config.CONFIG)
+        _ = spack.compilers.get_compiler_config(spack.config.CONFIG, init_config=True)
 
         # Early return if there is nothing to do
         if len(args) == 0:
@@ -2161,23 +2174,16 @@ def _get_environment_specs(self, recurse_dependencies=True):
 
         return specs
 
-    def _concrete_specs_dict(self):
+    def _to_lockfile_dict(self):
+        """Create a dictionary to store a lockfile for this environment."""
         concrete_specs = {}
         for s in traverse.traverse_nodes(self.specs_by_hash.values(), key=traverse.by_dag_hash):
             spec_dict = s.node_dict_with_hashes(hash=ht.dag_hash)
             # Assumes no legacy formats, since this was just created.
             spec_dict[ht.dag_hash.name] = s.dag_hash()
             concrete_specs[s.dag_hash()] = spec_dict
-        return concrete_specs
 
-    def _concrete_roots_dict(self):
         hash_spec_list = zip(self.concretized_order, self.concretized_user_specs)
-        return [{"hash": h, "spec": str(s)} for h, s in hash_spec_list]
-
-    def _to_lockfile_dict(self):
-        """Create a dictionary to store a lockfile for this environment."""
-        concrete_specs = self._concrete_specs_dict()
-        root_specs = self._concrete_roots_dict()
 
         spack_dict = {"version": spack.spack_version}
         spack_commit = spack.main.get_spack_commit()
@@ -2198,7 +2204,7 @@ def _to_lockfile_dict(self):
             # spack version information
             "spack": spack_dict,
             # users specs + hashes are the 'roots' of the environment
-            "roots": root_specs,
+            "roots": [{"hash": h, "spec": str(s)} for h, s in hash_spec_list],
             # Concrete specs by hash, including dependencies
             "concrete_specs": concrete_specs,
         }

lib/spack/spack/fetch_strategy.py

@@ -30,7 +30,6 @@
 import shutil
 import urllib.error
 import urllib.parse
-import urllib.request
 from pathlib import PurePath
 from typing import List, Optional
 
@@ -54,7 +53,7 @@
 import spack.version
 import spack.version.git_ref_lookup
 from spack.util.compression import decompressor_for
-from spack.util.executable import CommandNotFoundError, Executable, which
+from spack.util.executable import CommandNotFoundError, which
 
 #: List of all fetch strategies, created by FetchStrategy metaclass.
 all_strategies = []
@@ -246,30 +245,38 @@ class URLFetchStrategy(FetchStrategy):
 
     # these are checksum types. The generic 'checksum' is deprecated for
     # specific hash names, but we need it for backward compatibility
-    optional_attrs = [*crypto.hashes.keys(), "checksum"]
+    optional_attrs = list(crypto.hashes.keys()) + ["checksum"]
 
-    def __init__(self, *, url: str, checksum: Optional[str] = None, **kwargs) -> None:
+    def __init__(self, url=None, checksum=None, **kwargs):
         super().__init__(**kwargs)
 
-        self.url = url
+        # Prefer values in kwargs to the positionals.
+        self.url = kwargs.get("url", url)
         self.mirrors = kwargs.get("mirrors", [])
 
         # digest can be set as the first argument, or from an explicit
         # kwarg by the hash name.
-        self.digest: Optional[str] = checksum
+        self.digest = kwargs.get("checksum", checksum)
         for h in self.optional_attrs:
             if h in kwargs:
                 self.digest = kwargs[h]
 
-        self.expand_archive: bool = kwargs.get("expand", True)
-        self.extra_options: dict = kwargs.get("fetch_options", {})
-        self._curl: Optional[Executable] = None
-        self.extension: Optional[str] = kwargs.get("extension", None)
+        self.expand_archive = kwargs.get("expand", True)
+        self.extra_options = kwargs.get("fetch_options", {})
+        self._curl = None
+
+        self.extension = kwargs.get("extension", None)
+
+        if not self.url:
+            raise ValueError("URLFetchStrategy requires a url for fetching.")
 
     @property
-    def curl(self) -> Executable:
+    def curl(self):
         if not self._curl:
-            self._curl = web_util.require_curl()
+            try:
+                self._curl = which("curl", required=True)
+            except CommandNotFoundError as exc:
+                tty.error(str(exc))
         return self._curl
 
     def source_id(self):
@@ -290,23 +297,27 @@ def candidate_urls(self):
     @_needs_stage
     def fetch(self):
         if self.archive_file:
-            tty.debug(f"Already downloaded {self.archive_file}")
+            tty.debug("Already downloaded {0}".format(self.archive_file))
             return
 
-        errors: List[Exception] = []
+        url = None
+        errors = []
         for url in self.candidate_urls:
+            if not web_util.url_exists(url):
+                tty.debug("URL does not exist: " + url)
+                continue
+
             try:
                 self._fetch_from_url(url)
                 break
             except FailedDownloadError as e:
-                errors.extend(e.exceptions)
-        else:
-            raise FailedDownloadError(*errors)
+                errors.append(str(e))
+
+        for msg in errors:
+            tty.debug(msg)
 
         if not self.archive_file:
-            raise FailedDownloadError(
-                RuntimeError(f"Missing archive {self.archive_file} after fetching")
-            )
+            raise FailedDownloadError(url)
 
     def _fetch_from_url(self, url):
         if spack.config.get("config:url_fetch_method") == "curl":
@@ -325,28 +336,27 @@ def _check_headers(self, headers):
     @_needs_stage
     def _fetch_urllib(self, url):
         save_file = self.stage.save_filename
+        tty.msg("Fetching {0}".format(url))
 
-        request = urllib.request.Request(url, headers={"User-Agent": web_util.SPACK_USER_AGENT})
-
+        # Run urllib but grab the mime type from the http headers
         try:
-            response = web_util.urlopen(request)
-        except (TimeoutError, urllib.error.URLError) as e:
+            url, headers, response = web_util.read_from_url(url)
+        except web_util.SpackWebError as e:
             # clean up archive on failure.
             if self.archive_file:
                 os.remove(self.archive_file)
             if os.path.lexists(save_file):
                 os.remove(save_file)
-            raise FailedDownloadError(e) from e
-
-        tty.msg(f"Fetching {url}")
+            msg = "urllib failed to fetch with error {0}".format(e)
+            raise FailedDownloadError(url, msg)
 
         if os.path.lexists(save_file):
             os.remove(save_file)
 
-        with open(save_file, "wb") as f:
-            shutil.copyfileobj(response, f)
+        with open(save_file, "wb") as _open_file:
+            shutil.copyfileobj(response, _open_file)
 
-        self._check_headers(str(response.headers))
+        self._check_headers(str(headers))
 
     @_needs_stage
     def _fetch_curl(self, url):
@@ -355,7 +365,7 @@ def _fetch_curl(self, url):
         if self.stage.save_filename:
             save_file = self.stage.save_filename
             partial_file = self.stage.save_filename + ".part"
-        tty.msg(f"Fetching {url}")
+        tty.msg("Fetching {0}".format(url))
         if partial_file:
             save_args = [
                 "-C",
@@ -395,8 +405,8 @@ def _fetch_curl(self, url):
 
             try:
                 web_util.check_curl_code(curl.returncode)
-            except spack.error.FetchError as e:
-                raise FailedDownloadError(e) from e
+            except spack.error.FetchError as err:
+                raise spack.fetch_strategy.FailedDownloadError(url, str(err))
 
         self._check_headers(headers)
 
@@ -463,7 +473,7 @@ def check(self):
         """Check the downloaded archive against a checksum digest.
         No-op if this stage checks code out of a repository."""
         if not self.digest:
-            raise NoDigestError(f"Attempt to check {self.__class__.__name__} with no digest.")
+            raise NoDigestError("Attempt to check URLFetchStrategy with no digest.")
 
         verify_checksum(self.archive_file, self.digest)
 
@@ -474,8 +484,8 @@ def reset(self):
         """
         if not self.archive_file:
             raise NoArchiveFileError(
-                f"Tried to reset {self.__class__.__name__} before fetching",
-                f"Failed on reset() for URL{self.url}",
+                "Tried to reset URLFetchStrategy before fetching",
+                "Failed on reset() for URL %s" % self.url,
             )
 
         # Remove everything but the archive from the stage
@@ -488,10 +498,14 @@ def reset(self):
         self.expand()
 
     def __repr__(self):
-        return f"{self.__class__.__name__}<{self.url}>"
+        url = self.url if self.url else "no url"
+        return "%s<%s>" % (self.__class__.__name__, url)
 
     def __str__(self):
-        return self.url
+        if self.url:
+            return self.url
+        else:
+            return "[no url]"
 
 
 @fetcher
@@ -504,7 +518,7 @@ def fetch(self):
 
         # check whether the cache file exists.
         if not os.path.isfile(path):
-            raise NoCacheError(f"No cache of {path}")
+            raise NoCacheError("No cache of %s" % path)
 
         # remove old symlink if one is there.
         filename = self.stage.save_filename
@@ -514,8 +528,8 @@ def fetch(self):
         # Symlink to local cached archive.
         symlink(path, filename)
 
-        # Remove link if checksum fails, or subsequent fetchers will assume they don't need to
-        # download.
+        # Remove link if checksum fails, or subsequent fetchers
+        # will assume they don't need to download.
         if self.digest:
             try:
                 self.check()
@@ -524,12 +538,12 @@ def fetch(self):
                 raise
 
         # Notify the user how we fetched.
-        tty.msg(f"Using cached archive: {path}")
+        tty.msg("Using cached archive: {0}".format(path))
 
 
 class OCIRegistryFetchStrategy(URLFetchStrategy):
-    def __init__(self, *, url: str, checksum: Optional[str] = None, **kwargs):
-        super().__init__(url=url, checksum=checksum, **kwargs)
+    def __init__(self, url=None, checksum=None, **kwargs):
+        super().__init__(url, checksum, **kwargs)
 
         self._urlopen = kwargs.get("_urlopen", spack.oci.opener.urlopen)
 
@@ -540,13 +554,13 @@ def fetch(self):
 
         try:
             response = self._urlopen(self.url)
-        except (TimeoutError, urllib.error.URLError) as e:
+        except urllib.error.URLError as e:
             # clean up archive on failure.
             if self.archive_file:
                 os.remove(self.archive_file)
             if os.path.lexists(file):
                 os.remove(file)
-            raise FailedDownloadError(e) from e
+            raise FailedDownloadError(self.url, f"Failed to fetch {self.url}: {e}") from e
 
         if os.path.lexists(file):
             os.remove(file)
@@ -574,18 +588,18 @@ def __init__(self, **kwargs):
         # Set a URL based on the type of fetch strategy.
         self.url = kwargs.get(self.url_attr, None)
         if not self.url:
-            raise ValueError(f"{self.__class__} requires {self.url_attr} argument.")
+            raise ValueError("%s requires %s argument." % (self.__class__, self.url_attr))
 
         for attr in self.optional_attrs:
             setattr(self, attr, kwargs.get(attr, None))
 
     @_needs_stage
     def check(self):
-        tty.debug(f"No checksum needed when fetching with {self.url_attr}")
+        tty.debug("No checksum needed when fetching with {0}".format(self.url_attr))
 
     @_needs_stage
     def expand(self):
-        tty.debug(f"Source fetched with {self.url_attr} is already expanded.")
+        tty.debug("Source fetched with %s is already expanded." % self.url_attr)
 
     @_needs_stage
     def archive(self, destination, *, exclude: Optional[str] = None):
@@ -605,10 +619,10 @@ def archive(self, destination, *, exclude: Optional[str] = None):
             )
 
     def __str__(self):
-        return f"VCS: {self.url}"
+        return "VCS: %s" % self.url
 
     def __repr__(self):
-        return f"{self.__class__}<{self.url}>"
+        return "%s<%s>" % (self.__class__, self.url)
 
 
 @fetcher
@@ -711,17 +725,11 @@ class GitFetchStrategy(VCSFetchStrategy):
         "submodules",
         "get_full_repo",
         "submodules_delete",
-        "git_sparse_paths",
     ]
 
     git_version_re = r"git version (\S+)"
 
     def __init__(self, **kwargs):
-
-        self.commit: Optional[str] = None
-        self.tag: Optional[str] = None
-        self.branch: Optional[str] = None
-
         # Discards the keywords in kwargs that may conflict with the next call
         # to __init__
         forwarded_args = copy.copy(kwargs)
@@ -732,7 +740,6 @@ def __init__(self, **kwargs):
         self.submodules = kwargs.get("submodules", False)
         self.submodules_delete = kwargs.get("submodules_delete", False)
         self.get_full_repo = kwargs.get("get_full_repo", False)
-        self.git_sparse_paths = kwargs.get("git_sparse_paths", None)
 
     @property
     def git_version(self):
@@ -770,71 +777,68 @@ def git(self):
 
     @property
     def cachable(self):
-        return self.cache_enabled and bool(self.commit)
+        return self.cache_enabled and bool(self.commit or self.tag)
 
     def source_id(self):
-        # TODO: tree-hash would secure download cache and mirrors, commit only secures checkouts.
-        return self.commit
+        return self.commit or self.tag
 
     def mirror_id(self):
-        if self.commit:
+        repo_ref = self.commit or self.tag or self.branch
+        if repo_ref:
             repo_path = urllib.parse.urlparse(self.url).path
-            result = os.path.sep.join(["git", repo_path, self.commit])
+            result = os.path.sep.join(["git", repo_path, repo_ref])
             return result
 
     def _repo_info(self):
         args = ""
-        if self.commit:
-            args = f" at commit {self.commit}"
-        elif self.tag:
-            args = f" at tag {self.tag}"
-        elif self.branch:
-            args = f" on branch {self.branch}"
 
-        return f"{self.url}{args}"
+        if self.commit:
+            args = " at commit {0}".format(self.commit)
+        elif self.tag:
+            args = " at tag {0}".format(self.tag)
+        elif self.branch:
+            args = " on branch {0}".format(self.branch)
+
+        return "{0}{1}".format(self.url, args)
 
     @_needs_stage
     def fetch(self):
         if self.stage.expanded:
-            tty.debug(f"Already fetched {self.stage.source_path}")
+            tty.debug("Already fetched {0}".format(self.stage.source_path))
             return
 
-        if self.git_sparse_paths:
-            self._sparse_clone_src()
-        else:
-            self._clone_src()
-        self.submodule_operations()
+        self.clone(commit=self.commit, branch=self.branch, tag=self.tag)
 
-    def bare_clone(self, dest: str) -> None:
+    def clone(self, dest=None, commit=None, branch=None, tag=None, bare=False):
         """
-        Execute a bare clone for metadata only
+        Clone a repository to a path.
 
-        Requires a destination since bare cloning does not provide source
-        and shouldn't be used for staging.
+        This method handles cloning from git, but does not require a stage.
+
+        Arguments:
+            dest (str or None): The path into which the code is cloned. If None,
+                requires a stage and uses the stage's source path.
+            commit (str or None): A commit to fetch from the remote. Only one of
+                commit, branch, and tag may be non-None.
+            branch (str or None): A branch to fetch from the remote.
+            tag (str or None): A tag to fetch from the remote.
+            bare (bool): Execute a "bare" git clone (--bare option to git)
         """
         # Default to spack source path
-        tty.debug(f"Cloning git repository: {self._repo_info()}")
+        dest = dest or self.stage.source_path
+        tty.debug("Cloning git repository: {0}".format(self._repo_info()))
 
         git = self.git
         debug = spack.config.get("config:debug")
 
-        # We don't need to worry about which commit/branch/tag is checked out
-        clone_args = ["clone", "--bare"]
-        if not debug:
-            clone_args.append("--quiet")
-        clone_args.extend([self.url, dest])
-        git(*clone_args)
-
-    def _clone_src(self) -> None:
-        """Clone a repository to a path using git."""
-        # Default to spack source path
-        dest = self.stage.source_path
-        tty.debug(f"Cloning git repository: {self._repo_info()}")
-
-        git = self.git
-        debug = spack.config.get("config:debug")
-
-        if self.commit:
+        if bare:
+            # We don't need to worry about which commit/branch/tag is checked out
+            clone_args = ["clone", "--bare"]
+            if not debug:
+                clone_args.append("--quiet")
+            clone_args.extend([self.url, dest])
+            git(*clone_args)
+        elif commit:
             # Need to do a regular clone and check out everything if
             # they asked for a particular commit.
             clone_args = ["clone", self.url]
@@ -853,7 +857,7 @@ def _clone_src(self) -> None:
                 )
 
             with working_dir(dest):
-                checkout_args = ["checkout", self.commit]
+                checkout_args = ["checkout", commit]
                 if not debug:
                     checkout_args.insert(1, "--quiet")
                 git(*checkout_args)
@@ -865,10 +869,10 @@ def _clone_src(self) -> None:
                 args.append("--quiet")
 
             # If we want a particular branch ask for it.
-            if self.branch:
-                args.extend(["--branch", self.branch])
-            elif self.tag and self.git_version >= spack.version.Version("1.8.5.2"):
-                args.extend(["--branch", self.tag])
+            if branch:
+                args.extend(["--branch", branch])
+            elif tag and self.git_version >= spack.version.Version("1.8.5.2"):
+                args.extend(["--branch", tag])
 
             # Try to be efficient if we're using a new enough git.
             # This checks out only one branch's history
@@ -900,7 +904,7 @@ def _clone_src(self) -> None:
                 # For tags, be conservative and check them out AFTER
                 # cloning.  Later git versions can do this with clone
                 # --branch, but older ones fail.
-                if self.tag and self.git_version < spack.version.Version("1.8.5.2"):
+                if tag and self.git_version < spack.version.Version("1.8.5.2"):
                     # pull --tags returns a "special" error code of 1 in
                     # older versions that we have to ignore.
                     # see: https://github.com/git/git/commit/19d122b
@@ -913,79 +917,6 @@ def _clone_src(self) -> None:
                     git(*pull_args, ignore_errors=1)
                     git(*co_args)
 
-    def _sparse_clone_src(self, **kwargs):
-        """Use git's sparse checkout feature to clone portions of a git repository"""
-        dest = self.stage.source_path
-        git = self.git
-
-        if self.git_version < spack.version.Version("2.26.0"):
-            # technically this should be supported for 2.25, but bumping for OS issues
-            # see https://github.com/spack/spack/issues/45771
-            # code paths exist where the package is not set.  Assure some indentifier for the
-            # package that was configured  for sparse checkout exists in the error message
-            identifier = str(self.url)
-            if self.package:
-                identifier += f" ({self.package.name})"
-            tty.warn(
-                (
-                    f"{identifier} is configured for git sparse-checkout "
-                    "but the git version is too old to support sparse cloning. "
-                    "Cloning the full repository instead."
-                )
-            )
-            self._clone_src()
-        else:
-            # default to depth=2 to allow for retention of some git properties
-            depth = kwargs.get("depth", 2)
-            needs_fetch = self.branch or self.tag
-            git_ref = self.branch or self.tag or self.commit
-
-            assert git_ref
-
-            clone_args = ["clone"]
-
-            if needs_fetch:
-                clone_args.extend(["--branch", git_ref])
-
-            if self.get_full_repo:
-                clone_args.append("--no-single-branch")
-            else:
-                clone_args.append("--single-branch")
-
-            clone_args.extend(
-                [f"--depth={depth}", "--no-checkout", "--filter=blob:none", self.url]
-            )
-
-            sparse_args = ["sparse-checkout", "set"]
-
-            if callable(self.git_sparse_paths):
-                sparse_args.extend(self.git_sparse_paths())
-            else:
-                sparse_args.extend([p for p in self.git_sparse_paths])
-
-            sparse_args.append("--cone")
-
-            checkout_args = ["checkout", git_ref]
-
-            if not spack.config.get("config:debug"):
-                clone_args.insert(1, "--quiet")
-                checkout_args.insert(1, "--quiet")
-
-            with temp_cwd():
-                git(*clone_args)
-                repo_name = get_single_file(".")
-                if self.stage:
-                    self.stage.srcdir = repo_name
-                shutil.move(repo_name, dest)
-
-            with working_dir(dest):
-                git(*sparse_args)
-                git(*checkout_args)
-
-    def submodule_operations(self):
-        dest = self.stage.source_path
-        git = self.git
-
         if self.submodules_delete:
             with working_dir(dest):
                 for submodule_to_delete in self.submodules_delete:
@@ -1038,7 +969,7 @@ def protocol_supports_shallow_clone(self):
         return not (self.url.startswith("http://") or self.url.startswith("/"))
 
     def __str__(self):
-        return f"[git] {self._repo_info()}"
+        return "[git] {0}".format(self._repo_info())
 
 
 @fetcher
@@ -1362,7 +1293,7 @@ def reset(self):
             shutil.move(scrubbed, source_path)
 
     def __str__(self):
-        return f"[hg] {self.url}"
+        return "[hg] %s" % self.url
 
 
 @fetcher
@@ -1371,21 +1302,46 @@ class S3FetchStrategy(URLFetchStrategy):
 
     url_attr = "s3"
 
+    def __init__(self, *args, **kwargs):
+        try:
+            super().__init__(*args, **kwargs)
+        except ValueError:
+            if not kwargs.get("url"):
+                raise ValueError("S3FetchStrategy requires a url for fetching.")
+
     @_needs_stage
     def fetch(self):
-        if not self.url.startswith("s3://"):
-            raise spack.error.FetchError(
-                f"{self.__class__.__name__} can only fetch from s3:// urls."
-            )
         if self.archive_file:
-            tty.debug(f"Already downloaded {self.archive_file}")
+            tty.debug("Already downloaded {0}".format(self.archive_file))
             return
-        self._fetch_urllib(self.url)
-        if not self.archive_file:
-            raise FailedDownloadError(
-                RuntimeError(f"Missing archive {self.archive_file} after fetching")
+
+        parsed_url = urllib.parse.urlparse(self.url)
+        if parsed_url.scheme != "s3":
+            raise spack.error.FetchError("S3FetchStrategy can only fetch from s3:// urls.")
+
+        tty.debug("Fetching {0}".format(self.url))
+
+        basename = os.path.basename(parsed_url.path)
+
+        with working_dir(self.stage.path):
+            _, headers, stream = web_util.read_from_url(self.url)
+
+            with open(basename, "wb") as f:
+                shutil.copyfileobj(stream, f)
+
+            content_type = web_util.get_header(headers, "Content-type")
+
+        if content_type == "text/html":
+            warn_content_type_mismatch(self.archive_file or "the archive")
+
+        if self.stage.save_filename:
+            llnl.util.filesystem.rename(
+                os.path.join(self.stage.path, basename), self.stage.save_filename
             )
 
+        if not self.archive_file:
+            raise FailedDownloadError(self.url)
+
 
 @fetcher
 class GCSFetchStrategy(URLFetchStrategy):
@@ -1393,22 +1349,43 @@ class GCSFetchStrategy(URLFetchStrategy):
 
     url_attr = "gs"
 
+    def __init__(self, *args, **kwargs):
+        try:
+            super().__init__(*args, **kwargs)
+        except ValueError:
+            if not kwargs.get("url"):
+                raise ValueError("GCSFetchStrategy requires a url for fetching.")
+
     @_needs_stage
     def fetch(self):
-        if not self.url.startswith("gs"):
-            raise spack.error.FetchError(
-                f"{self.__class__.__name__} can only fetch from gs:// urls."
-            )
         if self.archive_file:
-            tty.debug(f"Already downloaded {self.archive_file}")
+            tty.debug("Already downloaded {0}".format(self.archive_file))
             return
 
-        self._fetch_urllib(self.url)
+        parsed_url = urllib.parse.urlparse(self.url)
+        if parsed_url.scheme != "gs":
+            raise spack.error.FetchError("GCSFetchStrategy can only fetch from gs:// urls.")
+
+        tty.debug("Fetching {0}".format(self.url))
+
+        basename = os.path.basename(parsed_url.path)
+
+        with working_dir(self.stage.path):
+            _, headers, stream = web_util.read_from_url(self.url)
+
+            with open(basename, "wb") as f:
+                shutil.copyfileobj(stream, f)
+
+            content_type = web_util.get_header(headers, "Content-type")
+
+        if content_type == "text/html":
+            warn_content_type_mismatch(self.archive_file or "the archive")
+
+        if self.stage.save_filename:
+            os.rename(os.path.join(self.stage.path, basename), self.stage.save_filename)
 
         if not self.archive_file:
-            raise FailedDownloadError(
-                RuntimeError(f"Missing archive {self.archive_file} after fetching")
-            )
+            raise FailedDownloadError(self.url)
 
 
 @fetcher
@@ -1417,7 +1394,7 @@ class FetchAndVerifyExpandedFile(URLFetchStrategy):
     as well as after expanding it."""
 
     def __init__(self, url, archive_sha256: str, expanded_sha256: str):
-        super().__init__(url=url, checksum=archive_sha256)
+        super().__init__(url, archive_sha256)
         self.expanded_sha256 = expanded_sha256
 
     def expand(self):
@@ -1459,14 +1436,14 @@ def stable_target(fetcher):
     return False
 
 
-def from_url(url: str) -> URLFetchStrategy:
+def from_url(url):
     """Given a URL, find an appropriate fetch strategy for it.
     Currently just gives you a URLFetchStrategy that uses curl.
 
     TODO: make this return appropriate fetch strategies for other
           types of URLs.
     """
-    return URLFetchStrategy(url=url)
+    return URLFetchStrategy(url)
 
 
 def from_kwargs(**kwargs):
@@ -1535,12 +1512,10 @@ def _check_version_attributes(fetcher, pkg, version):
 def _extrapolate(pkg, version):
     """Create a fetcher from an extrapolated URL for this version."""
     try:
-        return URLFetchStrategy(url=pkg.url_for_version(version), fetch_options=pkg.fetch_options)
+        return URLFetchStrategy(pkg.url_for_version(version), fetch_options=pkg.fetch_options)
     except spack.package_base.NoURLError:
-        raise ExtrapolationError(
-            f"Can't extrapolate a URL for version {version} because "
-            f"package {pkg.name} defines no URLs"
-        )
+        msg = "Can't extrapolate a URL for version %s " "because package %s defines no URLs"
+        raise ExtrapolationError(msg % (version, pkg.name))
 
 
 def _from_merged_attrs(fetcher, pkg, version):
@@ -1557,11 +1532,8 @@ def _from_merged_attrs(fetcher, pkg, version):
     attrs["fetch_options"] = pkg.fetch_options
     attrs.update(pkg.versions[version])
 
-    if fetcher.url_attr == "git":
-        pkg_attr_list = ["submodules", "git_sparse_paths"]
-        for pkg_attr in pkg_attr_list:
-            if hasattr(pkg, pkg_attr):
-                attrs.setdefault(pkg_attr, getattr(pkg, pkg_attr))
+    if fetcher.url_attr == "git" and hasattr(pkg, "submodules"):
+        attrs.setdefault("submodules", pkg.submodules)
 
     return fetcher(**attrs)
 
@@ -1656,9 +1628,11 @@ def for_package_version(pkg, version=None):
     raise InvalidArgsError(pkg, version, **args)
 
 
-def from_url_scheme(url: str, **kwargs) -> FetchStrategy:
+def from_url_scheme(url, *args, **kwargs):
     """Finds a suitable FetchStrategy by matching its url_attr with the scheme
     in the given url."""
+
+    url = kwargs.get("url", url)
     parsed_url = urllib.parse.urlparse(url, scheme="file")
 
     scheme_mapping = kwargs.get("scheme_mapping") or {
@@ -1675,9 +1649,11 @@ def from_url_scheme(url: str, **kwargs) -> FetchStrategy:
     for fetcher in all_strategies:
         url_attr = getattr(fetcher, "url_attr", None)
         if url_attr and url_attr == scheme:
-            return fetcher(url=url, **kwargs)
+            return fetcher(url, *args, **kwargs)
 
-    raise ValueError(f'No FetchStrategy found for url with scheme: "{parsed_url.scheme}"')
+    raise ValueError(
+        'No FetchStrategy found for url with scheme: "{SCHEME}"'.format(SCHEME=parsed_url.scheme)
+    )
 
 
 def from_list_url(pkg):
@@ -1702,9 +1678,7 @@ def from_list_url(pkg):
                     )
 
                 # construct a fetcher
-                return URLFetchStrategy(
-                    url=url_from_list, checksum=checksum, fetch_options=pkg.fetch_options
-                )
+                return URLFetchStrategy(url_from_list, checksum, fetch_options=pkg.fetch_options)
             except KeyError as e:
                 tty.debug(e)
                 tty.msg("Cannot find version %s in url_list" % pkg.version)
@@ -1732,10 +1706,10 @@ def store(self, fetcher, relative_dest):
         mkdirp(os.path.dirname(dst))
         fetcher.archive(dst)
 
-    def fetcher(self, target_path: str, digest: Optional[str], **kwargs) -> CacheURLFetchStrategy:
+    def fetcher(self, target_path, digest, **kwargs):
         path = os.path.join(self.root, target_path)
         url = url_util.path_to_file_url(path)
-        return CacheURLFetchStrategy(url=url, checksum=digest, **kwargs)
+        return CacheURLFetchStrategy(url, digest, **kwargs)
 
     def destroy(self):
         shutil.rmtree(self.root, ignore_errors=True)
@@ -1748,9 +1722,9 @@ class NoCacheError(spack.error.FetchError):
 class FailedDownloadError(spack.error.FetchError):
     """Raised when a download fails."""
 
-    def __init__(self, *exceptions: Exception):
-        super().__init__("Failed to download")
-        self.exceptions = exceptions
+    def __init__(self, url, msg=""):
+        super().__init__("Failed to fetch file from URL: %s" % url, msg)
+        self.url = url
 
 
 class NoArchiveFileError(spack.error.FetchError):

lib/spack/spack/hash_types.py

@@ -37,12 +37,6 @@ def __call__(self, spec):
         """Run this hash on the provided spec."""
         return spec.spec_hash(self)
 
-    def __repr__(self):
-        return (
-            f"SpecHashDescriptor(depflag={self.depflag!r}, "
-            f"package_hash={self.package_hash!r}, name={self.name!r}, override={self.override!r})"
-        )
-
 
 #: Spack's deployment hash. Includes all inputs that can affect how a package is built.
 dag_hash = SpecHashDescriptor(depflag=dt.BUILD | dt.LINK | dt.RUN, package_hash=True, name="hash")

lib/spack/spack/hooks/__init__.py

@@ -20,7 +20,6 @@
 systems (e.g. modules, lmod, etc.) or to add other custom
 features.
 """
-import importlib
 
 from llnl.util.lang import ensure_last, list_modules
 
@@ -47,7 +46,11 @@ def _populate_hooks(cls):
 
         for name in relative_names:
             module_name = __name__ + "." + name
-            module_obj = importlib.import_module(module_name)
+            # When importing a module from a package, __import__('A.B', ...)
+            # returns package A when 'fromlist' is empty. If fromlist is not
+            # empty it returns the submodule B instead
+            # See: https://stackoverflow.com/a/2725668/771663
+            module_obj = __import__(module_name, fromlist=[None])
             cls._hooks.append((module_name, module_obj))
 
     @property

lib/spack/spack/hooks/autopush.py

@@ -23,7 +23,9 @@ def post_install(spec, explicit):
 
     # Push the package to all autopush mirrors
     for mirror in spack.mirror.MirrorCollection(binary=True, autopush=True).values():
-        signing_key = bindist.select_signing_key() if mirror.signed else None
-        with bindist.make_uploader(mirror=mirror, force=True, signing_key=signing_key) as uploader:
-            uploader.push_or_raise([spec])
+        bindist.push_or_raise(
+            spec,
+            mirror.push_url,
+            bindist.PushOptions(force=True, regenerate_index=False, unsigned=not mirror.signed),
+        )
         tty.msg(f"{spec.name}: Pushed to build cache: '{mirror.name}'")

lib/spack/spack/install_test.py

@@ -757,10 +757,6 @@ def test_process(pkg: Pb, kwargs):
             pkg.tester.status(pkg.spec.name, TestStatus.SKIPPED)
             return
 
-        # Make sure properly named build-time test methods actually run as
-        # stand-alone tests.
-        pkg.run_tests = True
-
         # run test methods from the package and all virtuals it provides
         v_names = virtuals(pkg)
         test_specs = [pkg.spec] + [spack.spec.Spec(v_name) for v_name in sorted(v_names)]

lib/spack/spack/installer.py

@@ -1611,7 +1611,9 @@ def _add_tasks(self, request: BuildRequest, all_deps):
 
     def _add_compiler_package_to_config(self, pkg: "spack.package_base.PackageBase") -> None:
         compiler_search_prefix = getattr(pkg, "compiler_search_prefix", pkg.spec.prefix)
-        spack.compilers.find_compilers([compiler_search_prefix])
+        spack.compilers.add_compilers_to_config(
+            spack.compilers.find_compilers([compiler_search_prefix])
+        )
 
     def _install_task(self, task: BuildTask, install_status: InstallStatus) -> None:
         """

lib/spack/spack/mirror.py

@@ -21,7 +21,6 @@
 from typing import List, Optional, Union
 
 import llnl.url
-import llnl.util.symlink
 import llnl.util.tty as tty
 from llnl.util.filesystem import mkdirp
 
@@ -31,7 +30,6 @@
 import spack.fetch_strategy
 import spack.mirror
 import spack.oci.image
-import spack.repo
 import spack.spec
 import spack.util.path
 import spack.util.spack_json as sjson
@@ -428,74 +426,51 @@ def _determine_extension(fetcher):
     return ext
 
 
-class MirrorLayout:
-    """A ``MirrorLayout`` object describes the relative path of a mirror entry."""
+class MirrorReference:
+    """A ``MirrorReference`` stores the relative paths where you can store a
+    package/resource in a mirror directory.
 
-    def __init__(self, path: str) -> None:
-        self.path = path
+    The appropriate storage location is given by ``storage_path``. The
+    ``cosmetic_path`` property provides a reference that a human could generate
+    themselves based on reading the details of the package.
+
+    A user can iterate over a ``MirrorReference`` object to get all the
+    possible names that might be used to refer to the resource in a mirror;
+    this includes names generated by previous naming schemes that are no-longer
+    reported by ``storage_path`` or ``cosmetic_path``.
+    """
+
+    def __init__(self, cosmetic_path, global_path=None):
+        self.global_path = global_path
+        self.cosmetic_path = cosmetic_path
+
+    @property
+    def storage_path(self):
+        if self.global_path:
+            return self.global_path
+        else:
+            return self.cosmetic_path
 
     def __iter__(self):
-        """Yield all paths including aliases where the resource can be found."""
-        yield self.path
-
-    def make_alias(self, root: str) -> None:
-        """Make the entry ``root / self.path`` available under a human readable alias"""
-        pass
+        if self.global_path:
+            yield self.global_path
+        yield self.cosmetic_path
 
 
-class DefaultLayout(MirrorLayout):
-    def __init__(self, alias_path: str, digest_path: Optional[str] = None) -> None:
-        # When we have a digest, it is used as the primary storage location. If not, then we use
-        # the human-readable alias. In case of mirrors of a VCS checkout, we currently do not have
-        # a digest, that's why an alias is required and a digest optional.
-        super().__init__(path=digest_path or alias_path)
-        self.alias = alias_path
-        self.digest_path = digest_path
+class OCIImageLayout:
+    """Follow the OCI Image Layout Specification to archive blobs
 
-    def make_alias(self, root: str) -> None:
-        """Symlink a human readible path in our mirror to the actual storage location."""
-        # We already use the human-readable path as the main storage location.
-        if not self.digest_path:
-            return
-
-        alias, digest = os.path.join(root, self.alias), os.path.join(root, self.digest_path)
-
-        alias_dir = os.path.dirname(alias)
-        relative_dst = os.path.relpath(digest, start=alias_dir)
-
-        mkdirp(alias_dir)
-        tmp = f"{alias}.tmp"
-        llnl.util.symlink.symlink(relative_dst, tmp)
-
-        try:
-            os.rename(tmp, alias)
-        except OSError:
-            # Clean up the temporary if possible
-            try:
-                os.unlink(tmp)
-            except OSError:
-                pass
-            raise
-
-    def __iter__(self):
-        if self.digest_path:
-            yield self.digest_path
-        yield self.alias
-
-
-class OCILayout(MirrorLayout):
-    """Follow the OCI Image Layout Specification to archive blobs where paths are of the form
-    ``blobs/<algorithm>/<digest>``"""
+    Paths are of the form `blobs/<algorithm>/<digest>`
+    """
 
     def __init__(self, digest: spack.oci.image.Digest) -> None:
-        super().__init__(os.path.join("blobs", digest.algorithm, digest.digest))
+        self.storage_path = os.path.join("blobs", digest.algorithm, digest.digest)
+
+    def __iter__(self):
+        yield self.storage_path
 
 
-def default_mirror_layout(
-    fetcher: "spack.fetch_strategy.FetchStrategy",
-    per_package_ref: str,
-    spec: Optional["spack.spec.Spec"] = None,
-) -> MirrorLayout:
+def mirror_archive_paths(fetcher, per_package_ref, spec=None):
     """Returns a ``MirrorReference`` object which keeps track of the relative
     storage path of the resource associated with the specified ``fetcher``."""
     ext = None
@@ -519,7 +494,7 @@ def default_mirror_layout(
     if global_ref and ext:
         global_ref += ".%s" % ext
 
-    return DefaultLayout(per_package_ref, global_ref)
+    return MirrorReference(per_package_ref, global_ref)
 
 
 def get_all_versions(specs):

lib/spack/spack/multimethod.py

@@ -25,11 +25,14 @@
 so package authors should use their judgement.
 """
 import functools
+import inspect
 from contextlib import contextmanager
 
-import spack.directives_meta
+from llnl.util.lang import caller_locals
+
+import spack.directives
 import spack.error
-import spack.spec
+from spack.spec import Spec
 
 
 class MultiMethodMeta(type):
@@ -132,7 +135,7 @@ def __call__(self, package_or_builder_self, *args, **kwargs):
         # its superclasses for successive calls. We don't have that
         # information within `SpecMultiMethod`, because it is not
         # associated with the package class.
-        for cls in package_or_builder_self.__class__.__mro__[1:]:
+        for cls in inspect.getmro(package_or_builder_self.__class__)[1:]:
             superself = cls.__dict__.get(self.__name__, None)
 
             if isinstance(superself, SpecMultiMethod):
@@ -162,9 +165,9 @@ def __init__(self, condition):
             condition (str): condition to be met
         """
         if isinstance(condition, bool):
-            self.spec = spack.spec.Spec() if condition else None
+            self.spec = Spec() if condition else None
         else:
-            self.spec = spack.spec.Spec(condition)
+            self.spec = Spec(condition)
 
     def __call__(self, method):
         """This annotation lets packages declare multiple versions of
@@ -226,9 +229,11 @@ def install(self, prefix):
            platform-specific versions.  There's not much we can do to get
            around this because of the way decorators work.
         """
-        assert (
-            MultiMethodMeta._locals is not None
-        ), "cannot use multimethod, missing MultiMethodMeta metaclass?"
+        # In Python 2, Get the first definition of the method in the
+        # calling scope by looking at the caller's locals. In Python 3,
+        # we handle this using MultiMethodMeta.__prepare__.
+        if MultiMethodMeta._locals is None:
+            MultiMethodMeta._locals = caller_locals()
 
         # Create a multimethod with this name if there is not one already
         original_method = MultiMethodMeta._locals.get(method.__name__)
@@ -261,17 +266,17 @@ def __enter__(self):
         and add their constraint to whatever may be already present in the directive
         `when=` argument.
         """
-        spack.directives_meta.DirectiveMeta.push_to_context(str(self.spec))
+        spack.directives.DirectiveMeta.push_to_context(str(self.spec))
 
     def __exit__(self, exc_type, exc_val, exc_tb):
-        spack.directives_meta.DirectiveMeta.pop_from_context()
+        spack.directives.DirectiveMeta.pop_from_context()
 
 
 @contextmanager
 def default_args(**kwargs):
-    spack.directives_meta.DirectiveMeta.push_default_args(kwargs)
+    spack.directives.DirectiveMeta.push_default_args(kwargs)
     yield
-    spack.directives_meta.DirectiveMeta.pop_default_args()
+    spack.directives.DirectiveMeta.pop_default_args()
 
 
 class MultiMethodError(spack.error.SpackError):

lib/spack/spack/oci/oci.py

@@ -6,6 +6,7 @@
 import hashlib
 import json
 import os
+import time
 import urllib.error
 import urllib.parse
 import urllib.request
@@ -42,6 +43,11 @@ def create_tarball(spec: spack.spec.Spec, tarfile_path):
     return spack.binary_distribution._do_create_tarball(tarfile_path, spec.prefix, buildinfo)
 
 
+def _log_upload_progress(digest: Digest, size: int, elapsed: float):
+    elapsed = max(elapsed, 0.001)  # guard against division by zero
+    tty.info(f"Uploaded {digest} ({elapsed:.2f}s, {size / elapsed / 1024 / 1024:.2f} MB/s)")
+
+
 def with_query_param(url: str, param: str, value: str) -> str:
     """Add a query parameter to a URL
 
@@ -135,6 +141,8 @@ def upload_blob(
     if not force and blob_exists(ref, digest, _urlopen):
         return False
 
+    start = time.time()
+
     with open(file, "rb") as f:
         file_size = os.fstat(f.fileno()).st_size
 
@@ -159,6 +167,7 @@ def upload_blob(
 
         # Created the blob in one go.
         if response.status == 201:
+            _log_upload_progress(digest, file_size, time.time() - start)
             return True
 
         # Otherwise, do another PUT request.
@@ -182,6 +191,8 @@ def upload_blob(
 
         spack.oci.opener.ensure_status(request, response, 201)
 
+    # print elapsed time and # MB/s
+    _log_upload_progress(digest, file_size, time.time() - start)
     return True
 
 
@@ -390,12 +401,15 @@ def make_stage(
 ) -> spack.stage.Stage:
     _urlopen = _urlopen or spack.oci.opener.urlopen
     fetch_strategy = spack.fetch_strategy.OCIRegistryFetchStrategy(
-        url=url, checksum=digest.digest, _urlopen=_urlopen
+        url, checksum=digest.digest, _urlopen=_urlopen
     )
     # Use blobs/<alg>/<encoded> as the cache path, which follows
     # the OCI Image Layout Specification. What's missing though,
     # is the `oci-layout` and `index.json` files, which are
     # required by the spec.
     return spack.stage.Stage(
-        fetch_strategy, mirror_paths=spack.mirror.OCILayout(digest), name=digest.digest, keep=keep
+        fetch_strategy,
+        mirror_paths=spack.mirror.OCIImageLayout(digest),
+        name=digest.digest,
+        keep=keep,
     )

lib/spack/spack/package_base.py

@@ -15,7 +15,7 @@
 import functools
 import glob
 import hashlib
-import importlib
+import inspect
 import io
 import os
 import re
@@ -197,12 +197,13 @@ def __init__(cls, name, bases, attr_dict):
         # that "foo" was a possible executable.
 
         # If a package has the executables or libraries  attribute then it's
-        # assumed to be detectable. Add a tag, so finding them is faster
+        # assumed to be detectable
         if hasattr(cls, "executables") or hasattr(cls, "libraries"):
-            # To add the tag, we need to copy the tags attribute, and attach it to
-            # the current class. We don't use append, since it might modify base classes,
-            # if "tags" is retrieved following the MRO.
-            cls.tags = getattr(cls, "tags", []) + [DetectablePackageMeta.TAG]
+            # Append a tag to each detectable package, so that finding them is faster
+            if not hasattr(cls, "tags"):
+                setattr(cls, "tags", [DetectablePackageMeta.TAG])
+            elif DetectablePackageMeta.TAG not in cls.tags:
+                cls.tags.append(DetectablePackageMeta.TAG)
 
             @classmethod
             def platform_executables(cls):
@@ -245,7 +246,10 @@ def determine_spec_details(cls, prefix, objs_in_prefix):
                         if version_str:
                             objs_by_version[version_str].append(obj)
                     except Exception as e:
-                        tty.debug(f"Cannot detect the version of '{obj}' [{str(e)}]")
+                        msg = (
+                            "An error occurred when trying to detect " 'the version of "{0}" [{1}]'
+                        )
+                        tty.debug(msg.format(obj, str(e)))
 
                 specs = []
                 for version_str, objs in objs_by_version.items():
@@ -258,23 +262,27 @@ def determine_spec_details(cls, prefix, objs_in_prefix):
                         if isinstance(variant, str):
                             variant = (variant, {})
                         variant_str, extra_attributes = variant
-                        spec_str = f"{cls.name}@{version_str} {variant_str}"
+                        spec_str = "{0}@{1} {2}".format(cls.name, version_str, variant_str)
 
                         # Pop a few reserved keys from extra attributes, since
                         # they have a different semantics
                         external_path = extra_attributes.pop("prefix", None)
                         external_modules = extra_attributes.pop("modules", None)
                         try:
-                            spec = spack.spec.Spec.from_detection(
+                            spec = spack.spec.Spec(
                                 spec_str,
                                 external_path=external_path,
                                 external_modules=external_modules,
-                                extra_attributes=extra_attributes,
                             )
                         except Exception as e:
-                            tty.debug(f'Parsing failed [spec_str="{spec_str}", error={str(e)}]')
+                            msg = 'Parsing failed [spec_str="{0}", error={1}]'
+                            tty.debug(msg.format(spec_str, str(e)))
                         else:
-                            specs.append(spec)
+                            specs.append(
+                                spack.spec.Spec.from_detection(
+                                    spec, extra_attributes=extra_attributes
+                                )
+                            )
 
                 return sorted(specs)
 
@@ -733,7 +741,7 @@ def __init__(self, spec):
             raise ValueError(msg.format(self))
 
         # init internal variables
-        self._stage: Optional[StageComposite] = None
+        self._stage = None
         self._fetcher = None
         self._tester: Optional["PackageTest"] = None
 
@@ -861,7 +869,7 @@ def module(cls):
         We use this to add variables to package modules.  This makes
         install() methods easier to write (e.g., can call configure())
         """
-        return importlib.import_module(cls.__module__)
+        return __import__(cls.__module__, fromlist=[cls.__name__])
 
     @classproperty
     def namespace(cls):
@@ -877,7 +885,7 @@ def fullname(cls):
     def fullnames(cls):
         """Fullnames for this package and any packages from which it inherits."""
         fullnames = []
-        for cls in cls.__mro__:
+        for cls in inspect.getmro(cls):
             namespace = getattr(cls, "namespace", None)
             if namespace:
                 fullnames.append("%s.%s" % (namespace, cls.name))
@@ -1091,10 +1099,9 @@ def _make_resource_stage(self, root_stage, resource):
             root=root_stage,
             resource=resource,
             name=self._resource_stage(resource),
-            mirror_paths=spack.mirror.default_mirror_layout(
+            mirror_paths=spack.mirror.mirror_archive_paths(
                 resource.fetcher, os.path.join(self.name, pretty_resource_name)
             ),
-            mirrors=spack.mirror.MirrorCollection(source=True).values(),
             path=self.path,
         )
 
@@ -1106,7 +1113,7 @@ def _make_root_stage(self, fetcher):
         # Construct a mirror path (TODO: get this out of package.py)
         format_string = "{name}-{version}"
         pretty_name = self.spec.format_path(format_string)
-        mirror_paths = spack.mirror.default_mirror_layout(
+        mirror_paths = spack.mirror.mirror_archive_paths(
             fetcher, os.path.join(self.name, pretty_name), self.spec
         )
         # Construct a path where the stage should build..
@@ -1115,7 +1122,6 @@ def _make_root_stage(self, fetcher):
         stage = Stage(
             fetcher,
             mirror_paths=mirror_paths,
-            mirrors=spack.mirror.MirrorCollection(source=True).values(),
             name=stage_name,
             path=self.path,
             search_fn=self._download_search,
@@ -1172,7 +1178,7 @@ def stage(self):
         return self._stage
 
     @stage.setter
-    def stage(self, stage: StageComposite):
+    def stage(self, stage):
         """Allow a stage object to be set to override the default."""
         self._stage = stage
 
@@ -1742,7 +1748,7 @@ def _has_make_target(self, target):
             bool: True if 'target' is found, else False
         """
         # Prevent altering LC_ALL for 'make' outside this function
-        make = copy.deepcopy(self.module.make)
+        make = copy.deepcopy(inspect.getmodule(self).make)
 
         # Use English locale for missing target message comparison
         make.add_default_env("LC_ALL", "C")
@@ -1792,7 +1798,7 @@ def _if_make_target_execute(self, target, *args, **kwargs):
         """
         if self._has_make_target(target):
             # Execute target
-            self.module.make(target, *args, **kwargs)
+            inspect.getmodule(self).make(target, *args, **kwargs)
 
     def _has_ninja_target(self, target):
         """Checks to see if 'target' is a valid target in a Ninja build script.
@@ -1803,7 +1809,7 @@ def _has_ninja_target(self, target):
         Returns:
             bool: True if 'target' is found, else False
         """
-        ninja = self.module.ninja
+        ninja = inspect.getmodule(self).ninja
 
         # Check if we have a Ninja build script
         if not os.path.exists("build.ninja"):
@@ -1832,7 +1838,7 @@ def _if_ninja_target_execute(self, target, *args, **kwargs):
         """
         if self._has_ninja_target(target):
             # Execute target
-            self.module.ninja(target, *args, **kwargs)
+            inspect.getmodule(self).ninja(target, *args, **kwargs)
 
     def _get_needed_resources(self):
         # We use intersects here cause it would also work if self.spec is abstract
@@ -2420,9 +2426,8 @@ def all_urls(self) -> List[str]:
         if hasattr(self, "url") and self.url:
             urls.append(self.url)
 
-        # fetch from first entry in urls to save time
         if hasattr(self, "urls") and self.urls:
-            urls.append(self.urls[0])
+            urls.extend(self.urls)
 
         for args in self.versions.values():
             if "url" in args:

lib/spack/spack/package_prefs.py

@@ -5,11 +5,10 @@
 import stat
 import warnings
 
-import spack.config
 import spack.error
 import spack.repo
-import spack.spec
 from spack.config import ConfigError
+from spack.util.path import canonicalize_path
 from spack.version import Version
 
 _lesser_spec_types = {"compiler": spack.spec.CompilerSpec, "version": Version}
@@ -155,6 +154,44 @@ def preferred_variants(cls, pkg_name):
         )
 
 
+def spec_externals(spec):
+    """Return a list of external specs (w/external directory path filled in),
+    one for each known external installation.
+    """
+    # break circular import.
+    from spack.util.module_cmd import path_from_modules  # noqa: F401
+
+    def _package(maybe_abstract_spec):
+        pkg_cls = spack.repo.PATH.get_pkg_class(spec.name)
+        return pkg_cls(maybe_abstract_spec)
+
+    allpkgs = spack.config.get("packages")
+    names = set([spec.name])
+    names |= set(vspec.name for vspec in _package(spec).virtuals_provided)
+
+    external_specs = []
+    for name in names:
+        pkg_config = allpkgs.get(name, {})
+        pkg_externals = pkg_config.get("externals", [])
+        for entry in pkg_externals:
+            spec_str = entry["spec"]
+            external_path = entry.get("prefix", None)
+            if external_path:
+                external_path = canonicalize_path(external_path)
+            external_modules = entry.get("modules", None)
+            external_spec = spack.spec.Spec.from_detection(
+                spack.spec.Spec(
+                    spec_str, external_path=external_path, external_modules=external_modules
+                ),
+                extra_attributes=entry.get("extra_attributes", {}),
+            )
+            if external_spec.intersects(spec):
+                external_specs.append(external_spec)
+
+    # Defensively copy returned specs
+    return [s.copy() for s in external_specs]
+
+
 def is_spec_buildable(spec):
     """Return true if the spec is configured as buildable"""
     allpkgs = spack.config.get("packages")

lib/spack/spack/patch.py

@@ -4,6 +4,7 @@
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 
 import hashlib
+import inspect
 import os
 import os.path
 import pathlib
@@ -184,8 +185,8 @@ def __init__(
         # search mro to look for the file
         abs_path: Optional[str] = None
         # At different times we call FilePatch on instances and classes
-        pkg_cls = pkg if isinstance(pkg, type) else pkg.__class__
-        for cls in pkg_cls.__mro__:  # type: ignore
+        pkg_cls = pkg if inspect.isclass(pkg) else pkg.__class__
+        for cls in inspect.getmro(pkg_cls):  # type: ignore
             if not hasattr(cls, "module"):
                 # We've gone too far up the MRO
                 break
@@ -318,19 +319,18 @@ def stage(self) -> "spack.stage.Stage":
                 self.url, archive_sha256=self.archive_sha256, expanded_sha256=self.sha256
             )
         else:
-            fetcher = fs.URLFetchStrategy(url=self.url, sha256=self.sha256, expand=False)
+            fetcher = fs.URLFetchStrategy(self.url, sha256=self.sha256, expand=False)
 
         # The same package can have multiple patches with the same name but
         # with different contents, therefore apply a subset of the hash.
         name = "{0}-{1}".format(os.path.basename(self.url), fetch_digest[:7])
 
         per_package_ref = os.path.join(self.owner.split(".")[-1], name)
-        mirror_ref = spack.mirror.default_mirror_layout(fetcher, per_package_ref)
+        mirror_ref = spack.mirror.mirror_archive_paths(fetcher, per_package_ref)
         self._stage = spack.stage.Stage(
             fetcher,
             name=f"{spack.stage.stage_prefix}patch-{fetch_digest}",
             mirror_paths=mirror_ref,
-            mirrors=spack.mirror.MirrorCollection(source=True).values(),
         )
         return self._stage
 

lib/spack/spack/platforms/__init__.py

@@ -4,7 +4,7 @@
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 import contextlib
 
-from ._functions import _host, by_name, platforms, reset
+from ._functions import _host, by_name, platforms, prevent_cray_detection, reset
 from ._platform import Platform
 from .darwin import Darwin
 from .freebsd import FreeBSD
@@ -23,6 +23,7 @@
     "host",
     "by_name",
     "reset",
+    "prevent_cray_detection",
 ]
 
 #: The "real" platform of the host running Spack. This should not be changed

lib/spack/spack/platforms/_functions.py

@@ -2,8 +2,12 @@
 # Spack Project Developers. See the top-level COPYRIGHT file for details.
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
+import contextlib
+
 import llnl.util.lang
 
+import spack.util.environment
+
 from .darwin import Darwin
 from .freebsd import FreeBSD
 from .linux import Linux
@@ -53,3 +57,14 @@ def by_name(name):
     """
     platform_cls = cls_by_name(name)
     return platform_cls() if platform_cls else None
+
+
+@contextlib.contextmanager
+def prevent_cray_detection():
+    """Context manager that prevents the detection of the Cray platform"""
+    reset()
+    try:
+        with spack.util.environment.set_env(MODULEPATH=""):
+            yield
+    finally:
+        reset()

lib/spack/spack/repo.py

@@ -149,12 +149,12 @@ def current_repository(self, value):
     @contextlib.contextmanager
     def switch_repo(self, substitute: "RepoType"):
         """Switch the current repository list for the duration of the context manager."""
-        old = self._repo
+        old = self.current_repository
         try:
-            self._repo = substitute
+            self.current_repository = substitute
             yield
         finally:
-            self._repo = old
+            self.current_repository = old
 
     def find_spec(self, fullname, python_path, target=None):
         # "target" is not None only when calling importlib.reload()
@@ -365,9 +365,9 @@ def __init__(self, namespace):
 
     def __getattr__(self, name):
         """Getattr lazily loads modules if they're not already loaded."""
-        submodule = f"{self.__package__}.{name}"
+        submodule = self.__package__ + "." + name
         try:
-            setattr(self, name, importlib.import_module(submodule))
+            setattr(self, name, __import__(submodule))
         except ImportError:
             msg = "'{0}' object has no attribute {1}"
             raise AttributeError(msg.format(type(self), name))
@@ -683,7 +683,7 @@ class RepoPath:
     def __init__(
         self,
         *repos: Union[str, "Repo"],
-        cache: Optional["spack.caches.FileCacheType"],
+        cache: "spack.caches.FileCacheType",
         overrides: Optional[Dict[str, Any]] = None,
     ) -> None:
         self.repos: List[Repo] = []
@@ -696,7 +696,6 @@ def __init__(
         for repo in repos:
             try:
                 if isinstance(repo, str):
-                    assert cache is not None, "cache must hold a value, when repo is a string"
                     repo = Repo(repo, cache=cache, overrides=overrides)
                 repo.finder(self)
                 self.put_last(repo)
@@ -708,10 +707,6 @@ def __init__(
                     f"    spack repo rm {repo}",
                 )
 
-    def ensure_unwrapped(self) -> "RepoPath":
-        """Ensure we unwrap this object from any dynamic wrapper (like Singleton)"""
-        return self
-
     def put_first(self, repo: "Repo") -> None:
         """Add repo first in the search path."""
         if isinstance(repo, RepoPath):
@@ -935,16 +930,6 @@ def is_virtual_safe(self, pkg_name: str) -> bool:
     def __contains__(self, pkg_name):
         return self.exists(pkg_name)
 
-    def marshal(self):
-        return (self.repos,)
-
-    @staticmethod
-    def unmarshal(repos):
-        return RepoPath(*repos, cache=None)
-
-    def __reduce__(self):
-        return RepoPath.unmarshal, self.marshal()
-
 
 class Repo:
     """Class representing a package repository in the filesystem.
@@ -1281,7 +1266,7 @@ def get_pkg_class(self, pkg_name: str) -> Type["spack.package_base.PackageBase"]
             raise RepoError(msg) from e
 
         cls = getattr(module, class_name)
-        if not isinstance(cls, type):
+        if not inspect.isclass(cls):
             tty.die(f"{pkg_name}.{class_name} is not a class")
 
         # Clear any prior changes to class attributes in case the class was loaded from the
@@ -1334,20 +1319,6 @@ def __repr__(self) -> str:
     def __contains__(self, pkg_name: str) -> bool:
         return self.exists(pkg_name)
 
-    @staticmethod
-    def unmarshal(root, cache, overrides):
-        """Helper method to unmarshal keyword arguments"""
-        return Repo(root, cache=cache, overrides=overrides)
-
-    def marshal(self):
-        cache = self._cache
-        if isinstance(cache, llnl.util.lang.Singleton):
-            cache = cache.instance
-        return self.root, cache, self.overrides
-
-    def __reduce__(self):
-        return Repo.unmarshal, self.marshal()
-
 
 RepoType = Union[Repo, RepoPath]
 

lib/spack/spack/schema/compilers.py

@@ -11,26 +11,6 @@
 
 import spack.schema.environment
 
-flags: Dict[str, Any] = {
-    "type": "object",
-    "additionalProperties": False,
-    "properties": {
-        "cflags": {"anyOf": [{"type": "string"}, {"type": "null"}]},
-        "cxxflags": {"anyOf": [{"type": "string"}, {"type": "null"}]},
-        "fflags": {"anyOf": [{"type": "string"}, {"type": "null"}]},
-        "cppflags": {"anyOf": [{"type": "string"}, {"type": "null"}]},
-        "ldflags": {"anyOf": [{"type": "string"}, {"type": "null"}]},
-        "ldlibs": {"anyOf": [{"type": "string"}, {"type": "null"}]},
-    },
-}
-
-
-extra_rpaths: Dict[str, Any] = {"type": "array", "default": [], "items": {"type": "string"}}
-
-implicit_rpaths: Dict[str, Any] = {
-    "anyOf": [{"type": "array", "items": {"type": "string"}}, {"type": "boolean"}]
-}
-
 #: Properties for inclusion in other schemas
 properties: Dict[str, Any] = {
     "compilers": {
@@ -55,7 +35,18 @@
                                 "fc": {"anyOf": [{"type": "string"}, {"type": "null"}]},
                             },
                         },
-                        "flags": flags,
+                        "flags": {
+                            "type": "object",
+                            "additionalProperties": False,
+                            "properties": {
+                                "cflags": {"anyOf": [{"type": "string"}, {"type": "null"}]},
+                                "cxxflags": {"anyOf": [{"type": "string"}, {"type": "null"}]},
+                                "fflags": {"anyOf": [{"type": "string"}, {"type": "null"}]},
+                                "cppflags": {"anyOf": [{"type": "string"}, {"type": "null"}]},
+                                "ldflags": {"anyOf": [{"type": "string"}, {"type": "null"}]},
+                                "ldlibs": {"anyOf": [{"type": "string"}, {"type": "null"}]},
+                            },
+                        },
                         "spec": {"type": "string"},
                         "operating_system": {"type": "string"},
                         "target": {"type": "string"},
@@ -63,9 +54,18 @@
                         "modules": {
                             "anyOf": [{"type": "string"}, {"type": "null"}, {"type": "array"}]
                         },
-                        "implicit_rpaths": implicit_rpaths,
+                        "implicit_rpaths": {
+                            "anyOf": [
+                                {"type": "array", "items": {"type": "string"}},
+                                {"type": "boolean"},
+                            ]
+                        },
                         "environment": spack.schema.environment.definition,
-                        "extra_rpaths": extra_rpaths,
+                        "extra_rpaths": {
+                            "type": "array",
+                            "default": [],
+                            "items": {"type": "string"},
+                        },
                     },
                 }
             },

lib/spack/spack/schema/config.py

@@ -84,6 +84,7 @@
             "build_language": {"type": "string"},
             "build_jobs": {"type": "integer", "minimum": 1},
             "ccache": {"type": "boolean"},
+            "concretizer": {"type": "string", "enum": ["original", "clingo"]},
             "db_lock_timeout": {"type": "integer", "minimum": 1},
             "package_lock_timeout": {
                 "anyOf": [{"type": "integer", "minimum": 1}, {"type": "null"}]
@@ -97,9 +98,9 @@
             "aliases": {"type": "object", "patternProperties": {r"\w[\w-]*": {"type": "string"}}},
         },
         "deprecatedProperties": {
-            "properties": ["concretizer"],
-            "message": "Spack supports only clingo as a concretizer from v0.23. "
-            "The config:concretizer config option is ignored.",
+            "properties": ["terminal_title"],
+            "message": "config:terminal_title has been replaced by "
+            "install_status and is ignored",
             "error": False,
         },
     }

lib/spack/spack/schema/packages.py

@@ -11,8 +11,6 @@
 
 import spack.schema.environment
 
-from .compilers import extra_rpaths, flags, implicit_rpaths
-
 permissions = {
     "type": "object",
     "additionalProperties": False,
@@ -186,16 +184,7 @@
                                     "type": "object",
                                     "additionalProperties": True,
                                     "properties": {
-                                        "compilers": {
-                                            "type": "object",
-                                            "patternProperties": {
-                                                r"(^\w[\w-]*)": {"type": "string"}
-                                            },
-                                        },
-                                        "environment": spack.schema.environment.definition,
-                                        "extra_rpaths": extra_rpaths,
-                                        "implicit_rpaths": implicit_rpaths,
-                                        "flags": flags,
+                                        "environment": spack.schema.environment.definition
                                     },
                                 },
                             },

lib/spack/spack/solver/asp.py

@@ -32,6 +32,7 @@
 import spack.config
 import spack.config as sc
 import spack.deptypes as dt
+import spack.directives
 import spack.environment as ev
 import spack.error
 import spack.package_base
@@ -284,14 +285,16 @@ def _create_counter(specs: List[spack.spec.Spec], tests: bool):
     return NoDuplicatesCounter(specs, tests=tests)
 
 
+def all_compilers_in_config(configuration):
+    return spack.compilers.all_compilers_from(configuration)
+
+
 def all_libcs() -> Set[spack.spec.Spec]:
     """Return a set of all libc specs targeted by any configured compiler. If none, fall back to
     libc determined from the current Python process if dynamically linked."""
 
     libcs = {
-        c.default_libc
-        for c in spack.compilers.all_compilers_from(spack.config.CONFIG)
-        if c.default_libc
+        c.default_libc for c in all_compilers_in_config(spack.config.CONFIG) if c.default_libc
     }
 
     if libcs:
@@ -610,7 +613,7 @@ def _external_config_with_implicit_externals(configuration):
     if not using_libc_compatibility():
         return packages_yaml
 
-    for compiler in spack.compilers.all_compilers_from(configuration):
+    for compiler in all_compilers_in_config(configuration):
         libc = compiler.default_libc
         if libc:
             entry = {"spec": f"{libc} %{compiler.spec}", "prefix": libc.external_path}
@@ -1877,7 +1880,8 @@ def _spec_clauses(
 
                 # validate variant value only if spec not concrete
                 if not spec.concrete:
-                    if not spec.virtual and vname not in spack.variant.reserved_names:
+                    reserved_names = spack.directives.reserved_names
+                    if not spec.virtual and vname not in reserved_names:
                         pkg_cls = self.pkg_class(spec.name)
                         try:
                             variant_def, _ = pkg_cls.variants[vname]
@@ -2998,7 +3002,7 @@ class CompilerParser:
 
     def __init__(self, configuration) -> None:
         self.compilers: Set[KnownCompiler] = set()
-        for c in spack.compilers.all_compilers_from(configuration):
+        for c in all_compilers_in_config(configuration):
             if using_libc_compatibility() and not c_compiler_runs(c):
                 tty.debug(
                     f"the C compiler {c.cc} does not exist, or does not run correctly."
@@ -3462,7 +3466,7 @@ def reorder_flags(self):
         """
         # reverse compilers so we get highest priority compilers that share a spec
         compilers = dict(
-            (c.spec, c) for c in reversed(spack.compilers.all_compilers_from(spack.config.CONFIG))
+            (c.spec, c) for c in reversed(all_compilers_in_config(spack.config.CONFIG))
         )
         cmd_specs = dict((s.name, s) for spec in self._command_line_specs for s in spec.traverse())
 

lib/spack/spack/spec.py

@@ -51,7 +51,6 @@
 import collections
 import collections.abc
 import enum
-import io
 import itertools
 import os
 import pathlib
@@ -71,6 +70,7 @@
 import spack.compiler
 import spack.compilers
 import spack.config
+import spack.dependency as dp
 import spack.deptypes as dt
 import spack.error
 import spack.hash_types as ht
@@ -1428,7 +1428,7 @@ def __init__(
         # init an empty spec that matches anything.
         self.name = None
         self.versions = vn.VersionList(":")
-        self.variants = VariantMap(self)
+        self.variants = vt.VariantMap(self)
         self.architecture = None
         self.compiler = None
         self.compiler_flags = FlagMap(self)
@@ -1640,7 +1640,7 @@ def _add_flag(self, name, value, propagate):
         Known flags currently include "arch"
         """
 
-        if propagate and name in vt.reserved_names:
+        if propagate and name in spack.directives.reserved_names:
             raise UnsupportedPropagationError(
                 f"Propagation with '==' is not supported for '{name}'."
             )
@@ -2578,27 +2578,22 @@ def from_signed_json(stream):
         return Spec.from_dict(extracted_json)
 
     @staticmethod
-    def from_detection(
-        spec_str: str,
-        *,
-        external_path: str,
-        external_modules: Optional[List[str]] = None,
-        extra_attributes: Optional[Dict] = None,
-    ) -> "Spec":
+    def from_detection(spec_str, extra_attributes=None):
         """Construct a spec from a spec string determined during external
         detection and attach extra attributes to it.
 
         Args:
-            spec_str: spec string
-            external_path: prefix of the external spec
-            external_modules: optional module files to be loaded when the external spec is used
-            extra_attributes: dictionary containing extra attributes
+            spec_str (str): spec string
+            extra_attributes (dict): dictionary containing extra attributes
+
+        Returns:
+            spack.spec.Spec: external spec
         """
-        s = Spec(spec_str, external_path=external_path, external_modules=external_modules)
+        s = Spec(spec_str)
         extra_attributes = syaml.sorted_dict(extra_attributes or {})
         # This is needed to be able to validate multi-valued variants,
         # otherwise they'll still be abstract in the context of detection.
-        substitute_abstract_variants(s)
+        vt.substitute_abstract_variants(s)
         s.extra_attributes = extra_attributes
         return s
 
@@ -2620,6 +2615,294 @@ def validate_detection(self):
         validate_fn = getattr(pkg_cls, "validate_detected_spec", lambda x, y: None)
         validate_fn(self, self.extra_attributes)
 
+    def _concretize_helper(self, concretizer, presets=None, visited=None):
+        """Recursive helper function for concretize().
+        This concretizes everything bottom-up.  As things are
+        concretized, they're added to the presets, and ancestors
+        will prefer the settings of their children.
+        """
+        if presets is None:
+            presets = {}
+        if visited is None:
+            visited = set()
+
+        if self.name in visited:
+            return False
+
+        if self.concrete:
+            visited.add(self.name)
+            return False
+
+        changed = False
+
+        # Concretize deps first -- this is a bottom-up process.
+        for name in sorted(self._dependencies):
+            # WARNING: This function is an implementation detail of the
+            # WARNING: original concretizer. Since with that greedy
+            # WARNING: algorithm we don't allow multiple nodes from
+            # WARNING: the same package in a DAG, here we hard-code
+            # WARNING: using index 0 i.e. we assume that we have only
+            # WARNING: one edge from package "name"
+            changed |= self._dependencies[name][0].spec._concretize_helper(
+                concretizer, presets, visited
+            )
+
+        if self.name in presets:
+            changed |= self.constrain(presets[self.name])
+        else:
+            # Concretize virtual dependencies last.  Because they're added
+            # to presets below, their constraints will all be merged, but we'll
+            # still need to select a concrete package later.
+            if not self.virtual:
+                changed |= any(
+                    (
+                        concretizer.concretize_develop(self),  # special variant
+                        concretizer.concretize_architecture(self),
+                        concretizer.concretize_compiler(self),
+                        concretizer.adjust_target(self),
+                        # flags must be concretized after compiler
+                        concretizer.concretize_compiler_flags(self),
+                        concretizer.concretize_version(self),
+                        concretizer.concretize_variants(self),
+                    )
+                )
+            presets[self.name] = self
+
+        visited.add(self.name)
+        return changed
+
+    def _replace_with(self, concrete):
+        """Replace this virtual spec with a concrete spec."""
+        assert self.virtual
+        virtuals = (self.name,)
+        for dep_spec in itertools.chain.from_iterable(self._dependents.values()):
+            dependent = dep_spec.parent
+            depflag = dep_spec.depflag
+
+            # remove self from all dependents, unless it is already removed
+            if self.name in dependent._dependencies:
+                del dependent._dependencies.edges[self.name]
+
+            # add the replacement, unless it is already a dep of dependent.
+            if concrete.name not in dependent._dependencies:
+                dependent._add_dependency(concrete, depflag=depflag, virtuals=virtuals)
+            else:
+                dependent.edges_to_dependencies(name=concrete.name)[0].update_virtuals(
+                    virtuals=virtuals
+                )
+
+    def _expand_virtual_packages(self, concretizer):
+        """Find virtual packages in this spec, replace them with providers,
+        and normalize again to include the provider's (potentially virtual)
+        dependencies.  Repeat until there are no virtual deps.
+
+        Precondition: spec is normalized.
+
+        .. todo::
+
+           If a provider depends on something that conflicts with
+           other dependencies in the spec being expanded, this can
+           produce a conflicting spec.  For example, if mpich depends
+           on hwloc@:1.3 but something in the spec needs hwloc1.4:,
+           then we should choose an MPI other than mpich.  Cases like
+           this are infrequent, but should implement this before it is
+           a problem.
+        """
+        # Make an index of stuff this spec already provides
+        self_index = spack.provider_index.ProviderIndex(
+            repository=spack.repo.PATH, specs=self.traverse(), restrict=True
+        )
+        changed = False
+        done = False
+
+        while not done:
+            done = True
+            for spec in list(self.traverse()):
+                replacement = None
+                if spec.external:
+                    continue
+                if spec.virtual:
+                    replacement = self._find_provider(spec, self_index)
+                    if replacement:
+                        # TODO: may break if in-place on self but
+                        # shouldn't happen if root is traversed first.
+                        spec._replace_with(replacement)
+                        done = False
+                        break
+
+                if not replacement:
+                    # Get a list of possible replacements in order of
+                    # preference.
+                    candidates = concretizer.choose_virtual_or_external(spec)
+
+                    # Try the replacements in order, skipping any that cause
+                    # satisfiability problems.
+                    for replacement in candidates:
+                        if replacement is spec:
+                            break
+
+                        # Replace spec with the candidate and normalize
+                        copy = self.copy()
+                        copy[spec.name]._dup(replacement, deps=False)
+
+                        try:
+                            # If there are duplicate providers or duplicate
+                            # provider deps, consolidate them and merge
+                            # constraints.
+                            copy.normalize(force=True)
+                            break
+                        except spack.error.SpecError:
+                            # On error, we'll try the next replacement.
+                            continue
+
+                # If replacement is external then trim the dependencies
+                if replacement.external:
+                    if spec._dependencies:
+                        for dep in spec.dependencies():
+                            del dep._dependents.edges[spec.name]
+                        changed = True
+                        spec.clear_dependencies()
+                    replacement.clear_dependencies()
+                    replacement.architecture = self.architecture
+
+                # TODO: could this and the stuff in _dup be cleaned up?
+                def feq(cfield, sfield):
+                    return (not cfield) or (cfield == sfield)
+
+                if replacement is spec or (
+                    feq(replacement.name, spec.name)
+                    and feq(replacement.versions, spec.versions)
+                    and feq(replacement.compiler, spec.compiler)
+                    and feq(replacement.architecture, spec.architecture)
+                    and feq(replacement._dependencies, spec._dependencies)
+                    and feq(replacement.variants, spec.variants)
+                    and feq(replacement.external_path, spec.external_path)
+                    and feq(replacement.external_modules, spec.external_modules)
+                ):
+                    continue
+                # Refine this spec to the candidate. This uses
+                # replace_with AND dup so that it can work in
+                # place. TODO: make this more efficient.
+                if spec.virtual:
+                    spec._replace_with(replacement)
+                    changed = True
+                if spec._dup(replacement, deps=False, cleardeps=False):
+                    changed = True
+
+                self_index.update(spec)
+                done = False
+                break
+
+        return changed
+
+    def _old_concretize(self, tests=False, deprecation_warning=True):
+        """A spec is concrete if it describes one build of a package uniquely.
+        This will ensure that this spec is concrete.
+
+        Args:
+            tests (list or bool): list of packages that will need test
+                dependencies, or True/False for test all/none
+            deprecation_warning (bool): enable or disable the deprecation
+                warning for the old concretizer
+
+        If this spec could describe more than one version, variant, or build
+        of a package, this will add constraints to make it concrete.
+
+        Some rigorous validation and checks are also performed on the spec.
+        Concretizing ensures that it is self-consistent and that it's
+        consistent with requirements of its packages. See flatten() and
+        normalize() for more details on this.
+        """
+        import spack.concretize
+
+        # Add a warning message to inform users that the original concretizer
+        # will be removed
+        if deprecation_warning:
+            msg = (
+                "the original concretizer is currently being used.\n\tUpgrade to "
+                '"clingo" at your earliest convenience. The original concretizer '
+                "will be removed from Spack in a future version."
+            )
+            warnings.warn(msg)
+
+        self.replace_hash()
+
+        if not self.name:
+            raise spack.error.SpecError("Attempting to concretize anonymous spec")
+
+        if self._concrete:
+            return
+
+        # take the spec apart once before starting the main concretization loop and resolving
+        # deps, but don't break dependencies during concretization as the spec is built.
+        user_spec_deps = self.flat_dependencies(disconnect=True)
+
+        changed = True
+        force = False
+        concretizer = spack.concretize.Concretizer(self.copy())
+        while changed:
+            changes = (
+                self.normalize(force, tests, user_spec_deps, disconnect=False),
+                self._expand_virtual_packages(concretizer),
+                self._concretize_helper(concretizer),
+            )
+            changed = any(changes)
+            force = True
+
+        visited_user_specs = set()
+        for dep in self.traverse():
+            visited_user_specs.add(dep.name)
+            pkg_cls = spack.repo.PATH.get_pkg_class(dep.name)
+            visited_user_specs.update(pkg_cls(dep).provided_virtual_names())
+
+        extra = set(user_spec_deps.keys()).difference(visited_user_specs)
+        if extra:
+            raise InvalidDependencyError(self.name, extra)
+
+        Spec.inject_patches_variant(self)
+
+        for s in self.traverse():
+            # TODO: Refactor this into a common method to build external specs
+            # TODO: or turn external_path into a lazy property
+            Spec.ensure_external_path_if_external(s)
+
+        # assign hashes and mark concrete
+        self._finalize_concretization()
+
+        # If any spec in the DAG is deprecated, throw an error
+        Spec.ensure_no_deprecated(self)
+
+        # Update externals as needed
+        for dep in self.traverse():
+            if dep.external:
+                dep.package.update_external_dependencies()
+
+        # Now that the spec is concrete we should check if
+        # there are declared conflicts
+        #
+        # TODO: this needs rethinking, as currently we can only express
+        # TODO: internal configuration conflicts within one package.
+        matches = []
+        for x in self.traverse():
+            if x.external:
+                # external specs are already built, don't worry about whether
+                # it's possible to build that configuration with Spack
+                continue
+
+            for when_spec, conflict_list in x.package_class.conflicts.items():
+                if x.satisfies(when_spec):
+                    for conflict_spec, msg in conflict_list:
+                        if x.satisfies(conflict_spec):
+                            when = when_spec.copy()
+                            when.name = x.name
+                            matches.append((x, conflict_spec, when, msg))
+        if matches:
+            raise ConflictsInSpecError(self, matches)
+
+        # Check if we can produce an optimized binary (will throw if
+        # there are declared inconsistencies)
+        self.architecture.target.optimization_flags(self.compiler)
+
     def _patches_assigned(self):
         """Whether patches have been assigned to this spec by the concretizer."""
         # FIXME: _patches_in_order_of_appearance is attached after concretization
@@ -2749,13 +3032,7 @@ def ensure_no_deprecated(root):
             msg += "    For each package listed, choose another spec\n"
             raise SpecDeprecatedError(msg)
 
-    def concretize(self, tests: Union[bool, List[str]] = False) -> None:
-        """Concretize the current spec.
-
-        Args:
-            tests: if False disregard 'test' dependencies, if a list of names activate them for
-                the packages in the list, if True activate 'test' dependencies for all packages.
-        """
+    def _new_concretize(self, tests=False):
         import spack.solver.asp
 
         self.replace_hash()
@@ -2789,6 +3066,19 @@ def concretize(self, tests: Union[bool, List[str]] = False) -> None:
         concretized = answer[node]
         self._dup(concretized)
 
+    def concretize(self, tests=False):
+        """Concretize the current spec.
+
+        Args:
+            tests (bool or list): if False disregard 'test' dependencies,
+                if a list of names activate them for the packages in the list,
+                if True activate 'test' dependencies for all packages.
+        """
+        if spack.config.get("config:concretizer", "clingo") == "clingo":
+            self._new_concretize(tests)
+        else:
+            self._old_concretize(tests)
+
     def _mark_root_concrete(self, value=True):
         """Mark just this spec (not dependencies) concrete."""
         if (not value) and self.concrete and self.installed:
@@ -2892,6 +3182,34 @@ def concretized(self, tests=False):
         clone.concretize(tests=tests)
         return clone
 
+    def flat_dependencies(self, disconnect: bool = False):
+        """Build DependencyMap of all of this spec's dependencies with their constraints merged.
+
+        Arguments:
+            disconnect: if True, disconnect all dependents and dependencies among nodes in this
+                spec's DAG.
+        """
+        flat_deps = {}
+        deptree = self.traverse(root=False)
+
+        for spec in deptree:
+            if spec.name not in flat_deps:
+                flat_deps[spec.name] = spec
+            else:
+                try:
+                    flat_deps[spec.name].constrain(spec)
+                except spack.error.UnsatisfiableSpecError as e:
+                    # DAG contains two instances of the same package with inconsistent constraints.
+                    raise InconsistentSpecError("Invalid Spec DAG: %s" % e.message) from e
+
+        if disconnect:
+            for spec in flat_deps.values():
+                if not spec.concrete:
+                    spec.clear_edges()
+            self.clear_dependencies()
+
+        return flat_deps
+
     def index(self, deptype="all"):
         """Return a dictionary that points to all the dependencies in this
         spec.
@@ -2901,6 +3219,312 @@ def index(self, deptype="all"):
             dm[spec.name].append(spec)
         return dm
 
+    def _evaluate_dependency_conditions(self, name):
+        """Evaluate all the conditions on a dependency with this name.
+
+        Args:
+            name (str): name of dependency to evaluate conditions on.
+
+        Returns:
+            (Dependency): new Dependency object combining all constraints.
+
+        If the package depends on <name> in the current spec
+        configuration, return the constrained dependency and
+        corresponding dependency types.
+
+        If no conditions are True (and we don't depend on it), return
+        ``(None, None)``.
+        """
+        vt.substitute_abstract_variants(self)
+        # evaluate when specs to figure out constraints on the dependency.
+        dep = None
+        for when_spec, deps_by_name in self.package_class.dependencies.items():
+            if not self.satisfies(when_spec):
+                continue
+
+            for dep_name, dependency in deps_by_name.items():
+                if dep_name != name:
+                    continue
+
+                if dep is None:
+                    dep = dp.Dependency(Spec(self.name), Spec(name), depflag=0)
+                try:
+                    dep.merge(dependency)
+                except spack.error.UnsatisfiableSpecError as e:
+                    e.message = (
+                        "Conflicting conditional dependencies for spec"
+                        "\n\n\t{0}\n\n"
+                        "Cannot merge constraint"
+                        "\n\n\t{1}\n\n"
+                        "into"
+                        "\n\n\t{2}".format(self, dependency.spec, dep.spec)
+                    )
+                    raise e
+
+        return dep
+
+    def _find_provider(self, vdep, provider_index):
+        """Find provider for a virtual spec in the provider index.
+        Raise an exception if there is a conflicting virtual
+        dependency already in this spec.
+        """
+        assert spack.repo.PATH.is_virtual_safe(vdep.name), vdep
+
+        # note that this defensively copies.
+        providers = provider_index.providers_for(vdep)
+
+        # If there is a provider for the vpkg, then use that instead of
+        # the virtual package.
+        if providers:
+            # Remove duplicate providers that can concretize to the same
+            # result.
+            for provider in providers:
+                for spec in providers:
+                    if spec is not provider and provider.intersects(spec):
+                        providers.remove(spec)
+            # Can't have multiple providers for the same thing in one spec.
+            if len(providers) > 1:
+                raise MultipleProviderError(vdep, providers)
+            return providers[0]
+        else:
+            # The user might have required something insufficient for
+            # pkg_dep -- so we'll get a conflict.  e.g., user asked for
+            # mpi@:1.1 but some package required mpi@2.1:.
+            required = provider_index.providers_for(vdep.name)
+            if len(required) > 1:
+                raise MultipleProviderError(vdep, required)
+            elif required:
+                raise UnsatisfiableProviderSpecError(required[0], vdep)
+
+    def _merge_dependency(self, dependency, visited, spec_deps, provider_index, tests):
+        """Merge dependency information from a Package into this Spec.
+
+        Args:
+            dependency (Dependency): dependency metadata from a package;
+                this is typically the result of merging *all* matching
+                dependency constraints from the package.
+            visited (set): set of dependency nodes already visited by
+                ``normalize()``.
+            spec_deps (dict): ``dict`` of all dependencies from the spec
+                being normalized.
+            provider_index (dict): ``provider_index`` of virtual dep
+                providers in the ``Spec`` as normalized so far.
+
+        NOTE: Caller should assume that this routine owns the
+        ``dependency`` parameter, i.e., it needs to be a copy of any
+        internal structures.
+
+        This is the core of ``normalize()``.  There are some basic steps:
+
+          * If dep is virtual, evaluate whether it corresponds to an
+            existing concrete dependency, and merge if so.
+
+          * If it's real and it provides some virtual dep, see if it provides
+            what some virtual dependency wants and merge if so.
+
+          * Finally, if none of the above, merge dependency and its
+            constraints into this spec.
+
+        This method returns True if the spec was changed, False otherwise.
+
+        """
+        changed = False
+        dep = dependency.spec
+
+        # If it's a virtual dependency, try to find an existing
+        # provider in the spec, and merge that.
+        virtuals = ()
+        if spack.repo.PATH.is_virtual_safe(dep.name):
+            virtuals = (dep.name,)
+            visited.add(dep.name)
+            provider = self._find_provider(dep, provider_index)
+            if provider:
+                dep = provider
+        else:
+            index = spack.provider_index.ProviderIndex(
+                repository=spack.repo.PATH, specs=[dep], restrict=True
+            )
+            items = list(spec_deps.items())
+            for name, vspec in items:
+                if not spack.repo.PATH.is_virtual_safe(vspec.name):
+                    continue
+
+                if index.providers_for(vspec):
+                    vspec._replace_with(dep)
+                    del spec_deps[vspec.name]
+                    changed = True
+                else:
+                    required = index.providers_for(vspec.name)
+                    if required:
+                        raise UnsatisfiableProviderSpecError(required[0], dep)
+            provider_index.update(dep)
+
+        # If the spec isn't already in the set of dependencies, add it.
+        # Note: dep is always owned by this method. If it's from the
+        # caller, it's a copy from _evaluate_dependency_conditions. If it
+        # comes from a vdep, it's a defensive copy from _find_provider.
+        if dep.name not in spec_deps:
+            if self.concrete:
+                return False
+
+            spec_deps[dep.name] = dep
+            changed = True
+        else:
+            # merge package/vdep information into spec
+            try:
+                tty.debug("{0} applying constraint {1}".format(self.name, str(dep)))
+                changed |= spec_deps[dep.name].constrain(dep)
+            except spack.error.UnsatisfiableSpecError as e:
+                fmt = "An unsatisfiable {0}".format(e.constraint_type)
+                fmt += " constraint has been detected for spec:"
+                fmt += "\n\n{0}\n\n".format(spec_deps[dep.name].tree(indent=4))
+                fmt += "while trying to concretize the partial spec:"
+                fmt += "\n\n{0}\n\n".format(self.tree(indent=4))
+                fmt += "{0} requires {1} {2} {3}, but spec asked for {4}"
+
+                e.message = fmt.format(
+                    self.name, dep.name, e.constraint_type, e.required, e.provided
+                )
+
+                raise
+
+        # Add merged spec to my deps and recurse
+        spec_dependency = spec_deps[dep.name]
+        if dep.name not in self._dependencies:
+            self._add_dependency(spec_dependency, depflag=dependency.depflag, virtuals=virtuals)
+
+        changed |= spec_dependency._normalize_helper(visited, spec_deps, provider_index, tests)
+        return changed
+
+    def _normalize_helper(self, visited, spec_deps, provider_index, tests):
+        """Recursive helper function for _normalize."""
+        if self.name in visited:
+            return False
+        visited.add(self.name)
+
+        # If we descend into a virtual spec, there's nothing more
+        # to normalize.  Concretize will finish resolving it later.
+        if self.virtual or self.external:
+            return False
+
+        # Avoid recursively adding constraints for already-installed packages:
+        # these may include build dependencies which are not needed for this
+        # install (since this package is already installed).
+        if self.concrete and self.installed:
+            return False
+
+        # Combine constraints from package deps with constraints from
+        # the spec, until nothing changes.
+        any_change = False
+        changed = True
+
+        while changed:
+            changed = False
+            for dep_name in self.package_class.dependency_names():
+                # Do we depend on dep_name?  If so pkg_dep is not None.
+                dep = self._evaluate_dependency_conditions(dep_name)
+
+                # If dep is a needed dependency, merge it.
+                if dep:
+                    merge = (
+                        # caller requested test dependencies
+                        tests is True
+                        or (tests and self.name in tests)
+                        or
+                        # this is not a test-only dependency
+                        (dep.depflag & ~dt.TEST)
+                    )
+
+                    if merge:
+                        changed |= self._merge_dependency(
+                            dep, visited, spec_deps, provider_index, tests
+                        )
+            any_change |= changed
+
+        return any_change
+
+    def normalize(self, force=False, tests=False, user_spec_deps=None, disconnect=True):
+        """When specs are parsed, any dependencies specified are hanging off
+        the root, and ONLY the ones that were explicitly provided are there.
+        Normalization turns a partial flat spec into a DAG, where:
+
+        1. Known dependencies of the root package are in the DAG.
+        2. Each node's dependencies dict only contains its known direct
+           deps.
+        3. There is only ONE unique spec for each package in the DAG.
+
+           * This includes virtual packages.  If there a non-virtual
+             package that provides a virtual package that is in the spec,
+             then we replace the virtual package with the non-virtual one.
+
+        TODO: normalize should probably implement some form of cycle
+        detection, to ensure that the spec is actually a DAG.
+        """
+        if not self.name:
+            raise spack.error.SpecError("Attempting to normalize anonymous spec")
+
+        # Set _normal and _concrete to False when forced
+        if force and not self._concrete:
+            self._normal = False
+
+        if self._normal:
+            return False
+
+        # Ensure first that all packages & compilers in the DAG exist.
+        self.validate_or_raise()
+        # Clear the DAG and collect all dependencies in the DAG, which will be
+        # reapplied as constraints. All dependencies collected this way will
+        # have been created by a previous execution of 'normalize'.
+        # A dependency extracted here will only be reintegrated if it is
+        # discovered to apply according to _normalize_helper, so
+        # user-specified dependencies are recorded separately in case they
+        # refer to specs which take several normalization passes to
+        # materialize.
+        all_spec_deps = self.flat_dependencies(disconnect=disconnect)
+
+        if user_spec_deps:
+            for name, spec in user_spec_deps.items():
+                if not name:
+                    msg = "Attempted to normalize anonymous dependency spec"
+                    msg += " %s" % spec
+                    raise InvalidSpecDetected(msg)
+                if name not in all_spec_deps:
+                    all_spec_deps[name] = spec
+                else:
+                    all_spec_deps[name].constrain(spec)
+
+        # Initialize index of virtual dependency providers if
+        # concretize didn't pass us one already
+        provider_index = spack.provider_index.ProviderIndex(
+            repository=spack.repo.PATH, specs=[s for s in all_spec_deps.values()], restrict=True
+        )
+
+        # traverse the package DAG and fill out dependencies according
+        # to package files & their 'when' specs
+        visited = set()
+
+        any_change = self._normalize_helper(visited, all_spec_deps, provider_index, tests)
+
+        # remove any leftover dependents outside the spec from, e.g., pruning externals
+        valid = {id(spec) for spec in all_spec_deps.values()} | {id(self)}
+        for spec in all_spec_deps.values():
+            remove = [dep for dep in spec.dependents() if id(dep) not in valid]
+            for dep in remove:
+                del spec._dependents.edges[dep.name]
+                del dep._dependencies.edges[spec.name]
+
+        # Mark the spec as normal once done.
+        self._normal = True
+        return any_change
+
+    def normalized(self):
+        """
+        Return a normalized copy of this spec without modifying this spec.
+        """
+        clone = self.copy()
+        clone.normalize()
+        return clone
+
     def validate_or_raise(self):
         """Checks that names and values in this spec are real. If they're not,
         it will raise an appropriate exception.
@@ -2921,7 +3545,7 @@ def validate_or_raise(self):
             # Ensure correctness of variants (if the spec is not virtual)
             if not spec.virtual:
                 Spec.ensure_valid_variants(spec)
-                substitute_abstract_variants(spec)
+                vt.substitute_abstract_variants(spec)
 
     @staticmethod
     def ensure_valid_variants(spec):
@@ -2941,7 +3565,9 @@ def ensure_valid_variants(spec):
         pkg_variants = pkg_cls.variants
         # reserved names are variants that may be set on any package
         # but are not necessarily recorded by the package's class
-        not_existing = set(spec.variants) - (set(pkg_variants) | set(vt.reserved_names))
+        not_existing = set(spec.variants) - (
+            set(pkg_variants) | set(spack.directives.reserved_names)
+        )
         if not_existing:
             raise vt.UnknownVariantError(spec, not_existing)
 
@@ -3890,7 +4516,7 @@ def format_attribute(match_object: Match) -> str:
                 if part.startswith("_"):
                     raise SpecFormatStringError("Attempted to format private attribute")
                 else:
-                    if part == "variants" and isinstance(current, VariantMap):
+                    if part == "variants" and isinstance(current, vt.VariantMap):
                         # subscript instead of getattr for variant names
                         current = current[part]
                     else:
@@ -4345,155 +4971,9 @@ def attach_git_version_lookup(self):
                 v.attach_lookup(spack.version.git_ref_lookup.GitRefLookup(self.fullname))
 
 
-class VariantMap(lang.HashableMap):
-    """Map containing variant instances. New values can be added only
-    if the key is not already present."""
-
-    def __init__(self, spec: Spec):
-        super().__init__()
-        self.spec = spec
-
-    def __setitem__(self, name, vspec):
-        # Raise a TypeError if vspec is not of the right type
-        if not isinstance(vspec, vt.AbstractVariant):
-            raise TypeError(
-                "VariantMap accepts only values of variant types "
-                f"[got {type(vspec).__name__} instead]"
-            )
-
-        # Raise an error if the variant was already in this map
-        if name in self.dict:
-            msg = 'Cannot specify variant "{0}" twice'.format(name)
-            raise vt.DuplicateVariantError(msg)
-
-        # Raise an error if name and vspec.name don't match
-        if name != vspec.name:
-            raise KeyError(
-                f'Inconsistent key "{name}", must be "{vspec.name}" to ' "match VariantSpec"
-            )
-
-        # Set the item
-        super().__setitem__(name, vspec)
-
-    def substitute(self, vspec):
-        """Substitutes the entry under ``vspec.name`` with ``vspec``.
-
-        Args:
-            vspec: variant spec to be substituted
-        """
-        if vspec.name not in self:
-            raise KeyError(f"cannot substitute a key that does not exist [{vspec.name}]")
-
-        # Set the item
-        super().__setitem__(vspec.name, vspec)
-
-    def satisfies(self, other):
-        return all(k in self and self[k].satisfies(other[k]) for k in other)
-
-    def intersects(self, other):
-        return all(self[k].intersects(other[k]) for k in other if k in self)
-
-    def constrain(self, other: "VariantMap") -> bool:
-        """Add all variants in other that aren't in self to self. Also constrain all multi-valued
-        variants that are already present. Return True iff self changed"""
-        if other.spec is not None and other.spec._concrete:
-            for k in self:
-                if k not in other:
-                    raise vt.UnsatisfiableVariantSpecError(self[k], "<absent>")
-
-        changed = False
-        for k in other:
-            if k in self:
-                # If they are not compatible raise an error
-                if not self[k].compatible(other[k]):
-                    raise vt.UnsatisfiableVariantSpecError(self[k], other[k])
-                # If they are compatible merge them
-                changed |= self[k].constrain(other[k])
-            else:
-                # If it is not present copy it straight away
-                self[k] = other[k].copy()
-                changed = True
-
-        return changed
-
-    @property
-    def concrete(self):
-        """Returns True if the spec is concrete in terms of variants.
-
-        Returns:
-            bool: True or False
-        """
-        return self.spec._concrete or all(v in self for v in self.spec.package_class.variants)
-
-    def copy(self) -> "VariantMap":
-        clone = VariantMap(self.spec)
-        for name, variant in self.items():
-            clone[name] = variant.copy()
-        return clone
-
-    def __str__(self):
-        if not self:
-            return ""
-
-        # print keys in order
-        sorted_keys = sorted(self.keys())
-
-        # Separate boolean variants from key-value pairs as they print
-        # differently. All booleans go first to avoid ' ~foo' strings that
-        # break spec reuse in zsh.
-        bool_keys = []
-        kv_keys = []
-        for key in sorted_keys:
-            bool_keys.append(key) if isinstance(self[key].value, bool) else kv_keys.append(key)
-
-        # add spaces before and after key/value variants.
-        string = io.StringIO()
-
-        for key in bool_keys:
-            string.write(str(self[key]))
-
-        for key in kv_keys:
-            string.write(" ")
-            string.write(str(self[key]))
-
-        return string.getvalue()
-
-
-def substitute_abstract_variants(spec: Spec):
-    """Uses the information in `spec.package` to turn any variant that needs
-    it into a SingleValuedVariant.
-
-    This method is best effort. All variants that can be substituted will be
-    substituted before any error is raised.
-
-    Args:
-        spec: spec on which to operate the substitution
-    """
-    # This method needs to be best effort so that it works in matrix exlusion
-    # in $spack/lib/spack/spack/spec_list.py
-    failed = []
-    for name, v in spec.variants.items():
-        if name == "dev_path":
-            spec.variants.substitute(vt.SingleValuedVariant(name, v._original_value))
-            continue
-        elif name in vt.reserved_names:
-            continue
-        elif name not in spec.package_class.variants:
-            failed.append(name)
-            continue
-        pkg_variant, _ = spec.package_class.variants[name]
-        new_variant = pkg_variant.make_variant(v._original_value)
-        pkg_variant.validate_or_raise(new_variant, spec.package_class)
-        spec.variants.substitute(new_variant)
-
-    # Raise all errors at once
-    if failed:
-        raise vt.UnknownVariantError(spec, failed)
-
-
-def parse_with_version_concrete(spec_like: Union[str, Spec], compiler: bool = False):
+def parse_with_version_concrete(string: str, compiler: bool = False):
     """Same as Spec(string), but interprets @x as @=x"""
-    s: Union[CompilerSpec, Spec] = CompilerSpec(spec_like) if compiler else Spec(spec_like)
+    s: Union[CompilerSpec, Spec] = CompilerSpec(string) if compiler else Spec(string)
     interpreted_version = s.versions.concrete_range_as_version
     if interpreted_version:
         s.versions = vn.VersionList([interpreted_version])

lib/spack/spack/spec_list.py

@@ -5,7 +5,6 @@
 import itertools
 from typing import List
 
-import spack.spec
 import spack.variant
 from spack.error import SpackError
 from spack.spec import Spec
@@ -226,7 +225,7 @@ def _expand_matrix_constraints(matrix_config):
         # Catch exceptions because we want to be able to operate on
         # abstract specs without needing package information
         try:
-            spack.spec.substitute_abstract_variants(test_spec)
+            spack.variant.substitute_abstract_variants(test_spec)
         except spack.variant.UnknownVariantError:
             pass
 

lib/spack/spack/stage.py

@@ -13,7 +13,7 @@
 import stat
 import sys
 import tempfile
-from typing import Callable, Dict, Generator, Iterable, List, Optional, Set
+from typing import Callable, Dict, Iterable, Optional, Set
 
 import llnl.string
 import llnl.util.lang
@@ -40,7 +40,6 @@
 import spack.resource
 import spack.spec
 import spack.stage
-import spack.util.crypto
 import spack.util.lock
 import spack.util.path as sup
 import spack.util.pattern as pattern
@@ -352,10 +351,8 @@ class Stage(LockableStagingDir):
     def __init__(
         self,
         url_or_fetch_strategy,
-        *,
         name=None,
-        mirror_paths: Optional[spack.mirror.MirrorLayout] = None,
-        mirrors: Optional[Iterable[spack.mirror.Mirror]] = None,
+        mirror_paths=None,
         keep=False,
         path=None,
         lock=True,
@@ -364,30 +361,36 @@ def __init__(
         """Create a stage object.
         Parameters:
           url_or_fetch_strategy
-              URL of the archive to be downloaded into this stage, OR a valid FetchStrategy.
+              URL of the archive to be downloaded into this stage, OR
+              a valid FetchStrategy.
 
           name
-              If a name is provided, then this stage is a named stage and will persist between runs
-              (or if you construct another stage object later).  If name is not provided, then this
+              If a name is provided, then this stage is a named stage
+              and will persist between runs (or if you construct another
+              stage object later).  If name is not provided, then this
               stage will be given a unique name automatically.
 
           mirror_paths
-              If provided, Stage will search Spack's mirrors for this archive at each of the
-              provided relative mirror paths before using the default fetch strategy.
+              If provided, Stage will search Spack's mirrors for
+              this archive at each of the provided relative mirror paths
+              before using the default fetch strategy.
 
           keep
-              By default, when used as a context manager, the Stage is deleted on exit when no
-              exceptions are raised. Pass True to keep the stage intact even if no exceptions are
-              raised.
+              By default, when used as a context manager, the Stage
+              is deleted on exit when no exceptions are raised.
+              Pass True to keep the stage intact even if no
+              exceptions are raised.
 
          path
               If provided, the stage path to use for associated builds.
 
          lock
-              True if the stage directory file lock is to be used, False otherwise.
+              True if the stage directory file lock is to be used, False
+              otherwise.
 
          search_fn
-              The search function that provides the fetch strategy instance.
+              The search function that provides the fetch strategy
+              instance.
         """
         super().__init__(name, path, keep, lock)
 
@@ -403,37 +406,30 @@ def __init__(
         # self.fetcher can change with mirrors.
         self.default_fetcher = self.fetcher
         self.search_fn = search_fn
-        # If we fetch from a mirror, but the original data is from say git, we can currently not
-        # prove that they are equal (we don't even have a tree hash in package.py). This bool is
-        # used to skip checksum verification and instead warn the user.
-        if isinstance(self.default_fetcher, fs.URLFetchStrategy):
-            self.skip_checksum_for_mirror = not bool(self.default_fetcher.digest)
-        else:
-            self.skip_checksum_for_mirror = True
+        # used for mirrored archives of repositories.
+        self.skip_checksum_for_mirror = True
 
         self.srcdir = None
 
-        self.mirror_layout = mirror_paths
-        self.mirrors = list(mirrors) if mirrors else []
-        # Allow users the disable both mirrors and download cache
-        self.default_fetcher_only = False
+        self.mirror_paths = mirror_paths
 
     @property
     def expected_archive_files(self):
         """Possible archive file paths."""
+        paths = []
         fnames = []
         expanded = True
         if isinstance(self.default_fetcher, fs.URLFetchStrategy):
             expanded = self.default_fetcher.expand_archive
             fnames.append(url_util.default_download_filename(self.default_fetcher.url))
 
-        if self.mirror_layout:
-            fnames.append(os.path.basename(self.mirror_layout.path))
+        if self.mirror_paths:
+            fnames.extend(os.path.basename(x) for x in self.mirror_paths)
 
-        paths = [os.path.join(self.path, f) for f in fnames]
+        paths.extend(os.path.join(self.path, f) for f in fnames)
         if not expanded:
-            # If the download file is not compressed, the "archive" is a single file placed in
-            # Stage.source_path
+            # If the download file is not compressed, the "archive" is a
+            # single file placed in Stage.source_path
             paths.extend(os.path.join(self.source_path, f) for f in fnames)
 
         return paths
@@ -466,84 +462,104 @@ def source_path(self):
         """Returns the well-known source directory path."""
         return os.path.join(self.path, _source_path_subdir)
 
-    def _generate_fetchers(self, mirror_only=False) -> Generator[fs.FetchStrategy, None, None]:
-        fetchers: List[fs.FetchStrategy] = []
+    def disable_mirrors(self):
+        """The Stage will not attempt to look for the associated fetcher
+        target in any of Spack's mirrors (including the local download cache).
+        """
+        self.mirror_paths = []
+
+    def fetch(self, mirror_only=False, err_msg=None):
+        """Retrieves the code or archive
+
+        Args:
+            mirror_only (bool): only fetch from a mirror
+            err_msg (str or None): the error message to display if all fetchers
+                fail or ``None`` for the default fetch failure message
+        """
+        fetchers = []
         if not mirror_only:
             fetchers.append(self.default_fetcher)
 
-        # If this archive is normally fetched from a URL, then use the same digest.
-        if isinstance(self.default_fetcher, fs.URLFetchStrategy):
-            digest = self.default_fetcher.digest
-            expand = self.default_fetcher.expand_archive
-            extension = self.default_fetcher.extension
-        else:
-            digest = None
-            expand = True
-            extension = None
-
         # TODO: move mirror logic out of here and clean it up!
         # TODO: Or @alalazo may have some ideas about how to use a
         # TODO: CompositeFetchStrategy here.
-        if not self.default_fetcher_only and self.mirror_layout and self.mirrors:
+        self.skip_checksum_for_mirror = True
+        if self.mirror_paths:
+            # Join URLs of mirror roots with mirror paths. Because
+            # urljoin() will strip everything past the final '/' in
+            # the root, so we add a '/' if it is not present.
+            mirror_urls = [
+                url_util.join(mirror.fetch_url, rel_path)
+                for mirror in spack.mirror.MirrorCollection(source=True).values()
+                if not mirror.fetch_url.startswith("oci://")
+                for rel_path in self.mirror_paths
+            ]
+
+            # If this archive is normally fetched from a tarball URL,
+            # then use the same digest.  `spack mirror` ensures that
+            # the checksum will be the same.
+            digest = None
+            expand = True
+            extension = None
+            if isinstance(self.default_fetcher, fs.URLFetchStrategy):
+                digest = self.default_fetcher.digest
+                expand = self.default_fetcher.expand_archive
+                extension = self.default_fetcher.extension
+
+            # Have to skip the checksum for things archived from
+            # repositories.  How can this be made safer?
+            self.skip_checksum_for_mirror = not bool(digest)
+
             # Add URL strategies for all the mirrors with the digest
             # Insert fetchers in the order that the URLs are provided.
-            fetchers[:0] = (
-                fs.from_url_scheme(
-                    url_util.join(mirror.fetch_url, self.mirror_layout.path),
-                    checksum=digest,
-                    expand=expand,
-                    extension=extension,
+            for url in reversed(mirror_urls):
+                fetchers.insert(
+                    0, fs.from_url_scheme(url, digest, expand=expand, extension=extension)
                 )
-                for mirror in self.mirrors
-                if not mirror.fetch_url.startswith("oci://")  # no support for mirrors yet
-            )
 
-        if not self.default_fetcher_only and self.mirror_layout and self.default_fetcher.cachable:
-            fetchers.insert(
-                0,
-                spack.caches.FETCH_CACHE.fetcher(
-                    self.mirror_layout.path, digest, expand=expand, extension=extension
-                ),
-            )
+            if self.default_fetcher.cachable:
+                for rel_path in reversed(list(self.mirror_paths)):
+                    cache_fetcher = spack.caches.FETCH_CACHE.fetcher(
+                        rel_path, digest, expand=expand, extension=extension
+                    )
+                    fetchers.insert(0, cache_fetcher)
 
-        yield from fetchers
+        def generate_fetchers():
+            for fetcher in fetchers:
+                yield fetcher
+            # The search function may be expensive, so wait until now to
+            # call it so the user can stop if a prior fetcher succeeded
+            if self.search_fn and not mirror_only:
+                dynamic_fetchers = self.search_fn()
+                for fetcher in dynamic_fetchers:
+                    yield fetcher
 
-        # The search function may be expensive, so wait until now to call it so the user can stop
-        # if a prior fetcher succeeded
-        if self.search_fn and not mirror_only:
-            yield from self.search_fn()
+        def print_errors(errors):
+            for msg in errors:
+                tty.debug(msg)
 
-    def fetch(self, mirror_only: bool = False, err_msg: Optional[str] = None) -> None:
-        """Retrieves the code or archive
-
-        Args:
-            mirror_only: only fetch from a mirror
-            err_msg: the error message to display if all fetchers fail or ``None`` for the default
-                fetch failure message
-        """
-        errors: List[str] = []
-        for fetcher in self._generate_fetchers(mirror_only):
+        errors = []
+        for fetcher in generate_fetchers():
             try:
                 fetcher.stage = self
                 self.fetcher = fetcher
                 self.fetcher.fetch()
                 break
-            except fs.NoCacheError:
+            except spack.fetch_strategy.NoCacheError:
                 # Don't bother reporting when something is not cached.
                 continue
-            except fs.FailedDownloadError as f:
-                errors.extend(f"{fetcher}: {e.__class__.__name__}: {e}" for e in f.exceptions)
-                continue
             except spack.error.SpackError as e:
-                errors.append(f"{fetcher}: {e.__class__.__name__}: {e}")
+                errors.append("Fetching from {0} failed.".format(fetcher))
+                tty.debug(e)
                 continue
         else:
+            print_errors(errors)
+
             self.fetcher = self.default_fetcher
-            if err_msg:
-                raise spack.error.FetchError(err_msg)
-            raise spack.error.FetchError(
-                f"All fetchers failed for {self.name}", "\n".join(f"    {e}" for e in errors)
-            )
+            default_msg = "All fetchers failed for {0}".format(self.name)
+            raise spack.error.FetchError(err_msg or default_msg, None)
+
+        print_errors(errors)
 
     def steal_source(self, dest):
         """Copy the source_path directory in its entirety to directory dest
@@ -581,60 +597,56 @@ def steal_source(self, dest):
         self.destroy()
 
     def check(self):
-        """Check the downloaded archive against a checksum digest."""
+        """Check the downloaded archive against a checksum digest.
+        No-op if this stage checks code out of a repository."""
         if self.fetcher is not self.default_fetcher and self.skip_checksum_for_mirror:
-            cache = isinstance(self.fetcher, fs.CacheURLFetchStrategy)
-            if cache:
-                secure_msg = "your download cache is in a secure location"
-            else:
-                secure_msg = "you trust this mirror and have a secure connection"
             tty.warn(
-                f"Using {'download cache' if cache else 'a mirror'} instead of version control",
-                "The required sources are normally checked out from a version control system, "
-                f"but have been archived {'in download cache' if cache else 'on a mirror'}: "
-                f"{self.fetcher}. Spack lacks a tree hash to verify the integrity of this "
-                f"archive. Make sure {secure_msg}.",
+                "Fetching from mirror without a checksum!",
+                "This package is normally checked out from a version "
+                "control system, but it has been archived on a spack "
+                "mirror.  This means we cannot know a checksum for the "
+                "tarball in advance. Be sure that your connection to "
+                "this mirror is secure!",
             )
         elif spack.config.get("config:checksum"):
             self.fetcher.check()
 
     def cache_local(self):
-        spack.caches.FETCH_CACHE.store(self.fetcher, self.mirror_layout.path)
+        spack.caches.FETCH_CACHE.store(self.fetcher, self.mirror_paths.storage_path)
 
-    def cache_mirror(
-        self, mirror: spack.caches.MirrorCache, stats: spack.mirror.MirrorStats
-    ) -> None:
+    def cache_mirror(self, mirror, stats):
         """Perform a fetch if the resource is not already cached
 
         Arguments:
-            mirror: the mirror to cache this Stage's resource in
-            stats: this is updated depending on whether the caching operation succeeded or failed
+            mirror (spack.caches.MirrorCache): the mirror to cache this Stage's
+                resource in
+            stats (spack.mirror.MirrorStats): this is updated depending on whether the
+                caching operation succeeded or failed
         """
         if isinstance(self.default_fetcher, fs.BundleFetchStrategy):
-            # BundleFetchStrategy has no source to fetch. The associated fetcher does nothing but
-            # the associated stage may still exist. There is currently no method available on the
-            # fetcher to distinguish this ('cachable' refers to whether the fetcher refers to a
-            # resource with a fixed ID, which is not the same concept as whether there is anything
-            # to fetch at all) so we must examine the type of the fetcher.
+            # BundleFetchStrategy has no source to fetch. The associated
+            # fetcher does nothing but the associated stage may still exist.
+            # There is currently no method available on the fetcher to
+            # distinguish this ('cachable' refers to whether the fetcher
+            # refers to a resource with a fixed ID, which is not the same
+            # concept as whether there is anything to fetch at all) so we
+            # must examine the type of the fetcher.
             return
 
-        elif mirror.skip_unstable_versions and not fs.stable_target(self.default_fetcher):
+        if mirror.skip_unstable_versions and not fs.stable_target(self.default_fetcher):
             return
 
-        elif not self.mirror_layout:
-            return
-
-        absolute_storage_path = os.path.join(mirror.root, self.mirror_layout.path)
+        absolute_storage_path = os.path.join(mirror.root, self.mirror_paths.storage_path)
 
         if os.path.exists(absolute_storage_path):
             stats.already_existed(absolute_storage_path)
         else:
             self.fetch()
             self.check()
-            mirror.store(self.fetcher, self.mirror_layout.path)
+            mirror.store(self.fetcher, self.mirror_paths.storage_path)
             stats.added(absolute_storage_path)
 
-        self.mirror_layout.make_alias(mirror.root)
+        mirror.symlink(self.mirror_paths)
 
     def expand_archive(self):
         """Changes to the stage directory and attempt to expand the downloaded
@@ -642,9 +654,9 @@ def expand_archive(self):
         downloaded."""
         if not self.expanded:
             self.fetcher.expand()
-            tty.debug(f"Created stage in {self.path}")
+            tty.debug("Created stage in {0}".format(self.path))
         else:
-            tty.debug(f"Already staged {self.name} in {self.path}")
+            tty.debug("Already staged {0} in {1}".format(self.name, self.path))
 
     def restage(self):
         """Removes the expanded archive path if it exists, then re-expands
@@ -1163,22 +1175,20 @@ def _fetch_and_checksum(url, options, keep_stage, action_fn=None):
     try:
         url_or_fs = url
         if options:
-            url_or_fs = fs.URLFetchStrategy(url=url, fetch_options=options)
+            url_or_fs = fs.URLFetchStrategy(url, fetch_options=options)
 
         with Stage(url_or_fs, keep=keep_stage) as stage:
             # Fetch the archive
             stage.fetch()
-            archive = stage.archive_file
-            assert archive is not None, f"Archive not found for {url}"
-            if action_fn is not None and archive:
+            if action_fn is not None:
                 # Only run first_stage_function the first time,
                 # no need to run it every time
-                action_fn(archive, url)
+                action_fn(stage, url)
 
             # Checksum the archive and add it to the list
-            checksum = spack.util.crypto.checksum(hashlib.sha256, archive)
+            checksum = spack.util.crypto.checksum(hashlib.sha256, stage.archive_file)
         return checksum, None
-    except fs.FailedDownloadError:
+    except FailedDownloadError:
         return None, f"[WORKER] Failed to fetch {url}"
     except Exception as e:
         return None, f"[WORKER] Something failed on {url}, skipping.  ({e})"
@@ -1198,3 +1208,7 @@ class RestageError(StageError):
 
 class VersionFetchError(StageError):
     """Raised when we can't determine a URL to fetch a package."""
+
+
+# Keep this in namespace for convenience
+FailedDownloadError = fs.FailedDownloadError