Set version to 0.22.5

Ubuntu doesn't package kcov in v24.04 Since GitHub
started upgrading their runner images, this makes
our CI fail, see e.g.

https://github.com/spack/spack/actions/runs/12366970840/job/34518012887?pr=47854

This is a temporary workaround, while we prepare a
more stable fix.

* Don't run too many unit tests

.github/workflows/audit.yaml

@@ -28,7 +28,7 @@ jobs:
       run:
         shell: ${{ matrix.system.shell }}
     steps:
-    - uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29
+    - uses: actions/checkout@0ad4b8fadaa221de15dcec353f45205ec38ea70b
     - uses: actions/setup-python@82c7e631bb3cdc910f68e0081d67478d79c6982d
       with:
         python-version: ${{inputs.python_version}}
@@ -61,7 +61,7 @@ jobs:
           ./share/spack/qa/validate_last_exit.ps1
           spack -d audit externals
           ./share/spack/qa/validate_last_exit.ps1
-    - uses: codecov/codecov-action@125fc84a9a348dbcf27191600683ec096ec9021c
+    - uses: codecov/codecov-action@5ecb98a3c6b747ed38dc09f787459979aebb39be
       if: ${{ inputs.with_coverage == 'true' }}
       with:
         flags: unittests,audits

.github/workflows/bootstrap.yml

@@ -37,7 +37,7 @@ jobs:
               make patch unzip which xz python3 python3-devel tree \
               cmake bison
       - name: Checkout
-        uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29
+        uses: actions/checkout@0ad4b8fadaa221de15dcec353f45205ec38ea70b
         with:
           fetch-depth: 0
       - name: Bootstrap clingo
@@ -60,7 +60,7 @@ jobs:
         run: |
           brew install cmake bison tree
       - name: Checkout
-        uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29
+        uses: actions/checkout@0ad4b8fadaa221de15dcec353f45205ec38ea70b
         with:
           fetch-depth: 0
       - uses: actions/setup-python@82c7e631bb3cdc910f68e0081d67478d79c6982d
@@ -83,16 +83,14 @@ jobs:
     steps:
       - name: Setup macOS
         if: ${{ matrix.runner != 'ubuntu-latest' }}
+        run: brew install tree gawk
+      - name: Remove system executables
         run: |
-          brew install tree
-          # Remove GnuPG since we want to bootstrap it
-          sudo rm -rf /usr/local/bin/gpg
-      - name: Setup Ubuntu
-        if: ${{ matrix.runner == 'ubuntu-latest' }}
-        run: |
-          sudo rm -rf $(which gpg) $(which gpg2) $(which patchelf)
+          while [ -n "$(command -v gpg gpg2 patchelf)" ]; do
+            sudo rm $(command -v gpg gpg2 patchelf)
+          done
       - name: Checkout
-        uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29
+        uses: actions/checkout@0ad4b8fadaa221de15dcec353f45205ec38ea70b
         with:
           fetch-depth: 0
       - name: Bootstrap GnuPG
@@ -112,16 +110,14 @@ jobs:
     steps:
       - name: Setup macOS
         if: ${{ matrix.runner != 'ubuntu-latest' }}
+        run: brew install tree
+      - name: Remove system executables
         run: |
-          brew install tree
-          # Remove GnuPG since we want to bootstrap it
-          sudo rm -rf /usr/local/bin/gpg
-      - name: Setup Ubuntu
-        if: ${{ matrix.runner == 'ubuntu-latest' }}
-        run: |
-          sudo rm -rf $(which gpg) $(which gpg2) $(which patchelf)
+          while [ -n "$(command -v gpg gpg2 patchelf)" ]; do
+            sudo rm $(command -v gpg gpg2 patchelf)
+          done
       - name: Checkout
-        uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29
+        uses: actions/checkout@0ad4b8fadaa221de15dcec353f45205ec38ea70b
         with:
           fetch-depth: 0
       - uses: actions/setup-python@82c7e631bb3cdc910f68e0081d67478d79c6982d

.github/workflows/build-containers.yml

@@ -56,7 +56,7 @@ jobs:
     if: github.repository == 'spack/spack'
     steps:
       - name: Checkout
-        uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29
+        uses: actions/checkout@0ad4b8fadaa221de15dcec353f45205ec38ea70b
 
       - uses: docker/metadata-action@8e5442c4ef9f78752691e2d8f8d19755c6f78e81
         id: docker_meta

.github/workflows/ci.yaml

@@ -36,7 +36,7 @@ jobs:
       core: ${{ steps.filter.outputs.core }}
       packages: ${{ steps.filter.outputs.packages }}
     steps:
-      - uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29
+      - uses: actions/checkout@0ad4b8fadaa221de15dcec353f45205ec38ea70b
         if: ${{ github.event_name == 'push' }}
         with:
           fetch-depth: 0
@@ -77,13 +77,8 @@ jobs:
     needs: [ prechecks, changes ]
     uses: ./.github/workflows/unit_tests.yaml
     secrets: inherit
-  windows:
-    if: ${{ github.repository == 'spack/spack' && needs.changes.outputs.core == 'true' }}
-    needs: [ prechecks ]
-    uses: ./.github/workflows/windows_python.yml
-    secrets: inherit
   all:
-    needs: [ windows, unit-tests, bootstrap ]
+    needs: [ unit-tests, bootstrap ]
     runs-on: ubuntu-latest
     steps:
     - name: Success

.github/workflows/nightly-win-builds.yml

@@ -14,7 +14,7 @@ jobs:
   build-paraview-deps:
     runs-on: windows-latest
     steps:
-    - uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29
+    - uses: actions/checkout@0ad4b8fadaa221de15dcec353f45205ec38ea70b
       with:
         fetch-depth: 0
     - uses: actions/setup-python@82c7e631bb3cdc910f68e0081d67478d79c6982d

.github/workflows/style/requirements.txt

@@ -3,5 +3,5 @@ clingo==5.7.1
 flake8==7.0.0
 isort==5.13.2
 mypy==1.8.0
-types-six==1.16.21.20240513
+types-six==1.16.21.9
 vermin==1.6.0

.github/workflows/unit_tests.yaml

@@ -14,14 +14,14 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [ubuntu-latest]
+        os: [ubuntu-22.04]
         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
+          os: ubuntu-20.04
           concretizer: original
           on_develop: ${{ github.ref == 'refs/heads/develop' }}
         - python-version: '3.6'
@@ -30,28 +30,28 @@ jobs:
           on_develop: ${{ github.ref == 'refs/heads/develop' }}
         exclude:
         - python-version: '3.7'
-          os: ubuntu-latest
           concretizer: 'clingo'
+          os: ubuntu-22.04
           on_develop: false
         - python-version: '3.8'
-          os: ubuntu-latest
           concretizer: 'clingo'
+          os: ubuntu-22.04
           on_develop: false
         - python-version: '3.9'
-          os: ubuntu-latest
           concretizer: 'clingo'
+          os: ubuntu-22.04
           on_develop: false
         - python-version: '3.10'
-          os: ubuntu-latest
           concretizer: 'clingo'
+          os: ubuntu-22.04
           on_develop: false
         - python-version: '3.11'
-          os: ubuntu-latest
           concretizer: 'clingo'
+          os: ubuntu-22.04
           on_develop: false
 
     steps:
-    - uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29
+    - uses: actions/checkout@0ad4b8fadaa221de15dcec353f45205ec38ea70b
       with:
         fetch-depth: 0
     - uses: actions/setup-python@82c7e631bb3cdc910f68e0081d67478d79c6982d
@@ -91,16 +91,16 @@ jobs:
           UNIT_TEST_COVERAGE: ${{ matrix.python-version == '3.11' }}
       run: |
           share/spack/qa/run-unit-tests
-    - uses: codecov/codecov-action@125fc84a9a348dbcf27191600683ec096ec9021c
+    - uses: codecov/codecov-action@5ecb98a3c6b747ed38dc09f787459979aebb39be
       with:
         flags: unittests,linux,${{ matrix.concretizer }}
         token: ${{ secrets.CODECOV_TOKEN }}
         verbose: true
   # Test shell integration
   shell:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     steps:
-    - uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29
+    - uses: actions/checkout@0ad4b8fadaa221de15dcec353f45205ec38ea70b
       with:
         fetch-depth: 0
     - uses: actions/setup-python@82c7e631bb3cdc910f68e0081d67478d79c6982d
@@ -124,7 +124,7 @@ jobs:
           COVERAGE: true
       run: |
           share/spack/qa/run-shell-tests
-    - uses: codecov/codecov-action@125fc84a9a348dbcf27191600683ec096ec9021c
+    - uses: codecov/codecov-action@5ecb98a3c6b747ed38dc09f787459979aebb39be
       with:
         flags: shelltests,linux
         token: ${{ secrets.CODECOV_TOKEN }}
@@ -141,7 +141,7 @@ jobs:
           dnf install -y \
               bzip2 curl file gcc-c++ gcc gcc-gfortran git gnupg2 gzip \
               make patch tcl unzip which xz
-    - uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29
+    - uses: actions/checkout@0ad4b8fadaa221de15dcec353f45205ec38ea70b
     - name: Setup repo and non-root user
       run: |
           git --version
@@ -158,9 +158,9 @@ jobs:
           spack unit-test -k 'not cvs and not svn and not hg' -x --verbose
   # Test for the clingo based solver (using clingo-cffi)
   clingo-cffi:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     steps:
-    - uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29
+    - uses: actions/checkout@0ad4b8fadaa221de15dcec353f45205ec38ea70b
       with:
         fetch-depth: 0
     - uses: actions/setup-python@82c7e631bb3cdc910f68e0081d67478d79c6982d
@@ -185,7 +185,7 @@ jobs:
           SPACK_TEST_SOLVER: clingo
       run: |
           share/spack/qa/run-unit-tests
-    - uses: codecov/codecov-action@125fc84a9a348dbcf27191600683ec096ec9021c
+    - uses: codecov/codecov-action@5ecb98a3c6b747ed38dc09f787459979aebb39be
       with:
         flags: unittests,linux,clingo
         token: ${{ secrets.CODECOV_TOKEN }}
@@ -198,7 +198,7 @@ jobs:
         os: [macos-13, macos-14]
         python-version: ["3.11"]
     steps:
-    - uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29
+    - uses: actions/checkout@0ad4b8fadaa221de15dcec353f45205ec38ea70b
       with:
         fetch-depth: 0
     - uses: actions/setup-python@82c7e631bb3cdc910f68e0081d67478d79c6982d
@@ -223,8 +223,39 @@ jobs:
         $(which spack) solve zlib
         common_args=(--dist loadfile --tx '4*popen//python=./bin/spack-tmpconfig python -u ./bin/spack python' -x)
         $(which spack) unit-test --verbose --cov --cov-config=pyproject.toml --cov-report=xml:coverage.xml "${common_args[@]}"
-    - uses: codecov/codecov-action@125fc84a9a348dbcf27191600683ec096ec9021c
+    - uses: codecov/codecov-action@5ecb98a3c6b747ed38dc09f787459979aebb39be
       with:
         flags: unittests,macos
         token: ${{ secrets.CODECOV_TOKEN }}
         verbose: true
+  # Run unit tests on Windows
+  windows:
+    defaults:
+      run:
+        shell:
+          powershell Invoke-Expression -Command "./share/spack/qa/windows_test_setup.ps1"; {0}
+    runs-on: windows-latest
+    steps:
+    - uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29
+      with:
+        fetch-depth: 0
+    - uses: actions/setup-python@82c7e631bb3cdc910f68e0081d67478d79c6982d
+      with:
+        python-version: 3.9
+    - name: Install Python packages
+      run: |
+          python -m pip install --upgrade pip pywin32 setuptools pytest-cov clingo
+    - name: Create local develop
+      run: |
+        ./.github/workflows/setup_git.ps1
+    - name: Unit Test
+      run: |
+        spack unit-test -x --verbose --cov --cov-config=pyproject.toml
+        ./share/spack/qa/validate_last_exit.ps1
+        coverage combine -a
+        coverage xml
+    - uses: codecov/codecov-action@125fc84a9a348dbcf27191600683ec096ec9021c
+      with:
+        flags: unittests,windows
+        token: ${{ secrets.CODECOV_TOKEN }}
+        verbose: true

.github/workflows/valid-style.yml

@@ -18,7 +18,7 @@ jobs:
   validate:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29
+    - uses: actions/checkout@0ad4b8fadaa221de15dcec353f45205ec38ea70b
     - uses: actions/setup-python@82c7e631bb3cdc910f68e0081d67478d79c6982d
       with:
         python-version: '3.11'
@@ -35,7 +35,7 @@ jobs:
   style:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29
+    - uses: actions/checkout@0ad4b8fadaa221de15dcec353f45205ec38ea70b
       with:
         fetch-depth: 0
     - uses: actions/setup-python@82c7e631bb3cdc910f68e0081d67478d79c6982d
@@ -70,7 +70,7 @@ jobs:
           dnf install -y \
               bzip2 curl file gcc-c++ gcc gcc-gfortran git gnupg2 gzip \
               make patch tcl unzip which xz
-      - uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29
+      - uses: actions/checkout@0ad4b8fadaa221de15dcec353f45205ec38ea70b
       - name: Setup repo and non-root user
         run: |
           git --version

.github/workflows/windows_python.yml

@@ -1,83 +0,0 @@
-name: windows
-
-on:
-  workflow_call:
-
-concurrency:
-  group: windows-${{github.ref}}-${{github.event.pull_request.number || github.run_number}}
-  cancel-in-progress: true
-
-defaults:
-  run:
-    shell:
-     powershell Invoke-Expression -Command "./share/spack/qa/windows_test_setup.ps1"; {0}
-jobs:
-  unit-tests:
-    runs-on: windows-latest
-    steps:
-    - uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29
-      with:
-        fetch-depth: 0
-    - uses: actions/setup-python@82c7e631bb3cdc910f68e0081d67478d79c6982d
-      with:
-        python-version: 3.9
-    - name: Install Python packages
-      run: |
-          python -m pip install --upgrade pip pywin32 setuptools pytest-cov clingo
-    - name: Create local develop
-      run: |
-        ./.github/workflows/setup_git.ps1
-    - name: Unit Test
-      run: |
-        spack unit-test -x --verbose --cov --cov-config=pyproject.toml --ignore=lib/spack/spack/test/cmd
-        ./share/spack/qa/validate_last_exit.ps1
-        coverage combine -a
-        coverage xml
-    - uses: codecov/codecov-action@125fc84a9a348dbcf27191600683ec096ec9021c
-      with:
-        flags: unittests,windows
-        token: ${{ secrets.CODECOV_TOKEN }}
-        verbose: true
-  unit-tests-cmd:
-    runs-on: windows-latest
-    steps:
-    - uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29
-      with:
-        fetch-depth: 0
-    - uses: actions/setup-python@82c7e631bb3cdc910f68e0081d67478d79c6982d
-      with:
-        python-version: 3.9
-    - name: Install Python packages
-      run: |
-          python -m pip install --upgrade pip pywin32 setuptools coverage pytest-cov clingo
-    - name: Create local develop
-      run: |
-        ./.github/workflows/setup_git.ps1
-    - name: Command Unit Test
-      run: |
-        spack unit-test -x --verbose --cov --cov-config=pyproject.toml lib/spack/spack/test/cmd
-        ./share/spack/qa/validate_last_exit.ps1
-        coverage combine -a
-        coverage xml
-    - uses: codecov/codecov-action@125fc84a9a348dbcf27191600683ec096ec9021c
-      with:
-        flags: unittests,windows
-        token: ${{ secrets.CODECOV_TOKEN }}
-        verbose: true
-  build-abseil:
-    runs-on: windows-latest
-    steps:
-    - uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29
-      with:
-        fetch-depth: 0
-    - uses: actions/setup-python@82c7e631bb3cdc910f68e0081d67478d79c6982d
-      with:
-        python-version: 3.9
-    - name: Install Python packages
-      run: |
-          python -m pip install --upgrade pip pywin32 setuptools coverage
-    - name: Build Test
-      run: |
-        spack compiler find
-        spack -d external find cmake ninja
-        spack -d install abseil-cpp

.readthedocs.yml

@@ -14,3 +14,26 @@ sphinx:
 python:
   install:
     - requirements: lib/spack/docs/requirements.txt
+
+search:
+  ranking:
+    spack.html: -10
+    spack.*.html: -10
+    llnl.html: -10
+    llnl.*.html: -10
+    _modules/*: -10
+    command_index.html: -9
+    basic_usage.html: 5
+    configuration.html: 5
+    config_yaml.html: 5
+    packages_yaml.html: 5
+    build_settings.html: 5
+    environments.html: 5
+    containers.html: 5
+    mirrors.html: 5
+    module_file_support.html: 5
+    repositories.html: 5
+    binary_caches.html: 5
+    chain.html: 5
+    pipelines.html: 5
+    packaging_guide.html: 5

CHANGELOG.md

@@ -1,3 +1,424 @@
+# v0.22.5 (2025-02-21)
+
+## Bugfixes
+- Continue to mark non-roots as implicitly installed on partial env installs (#47183)
+
+## Notes
+- v0.22.4 is skipped to do an error in the release process
+
+# v0.22.3 (2024-11-18)
+
+## Bugfixes
+- Forward compatibility with Python 3.13 (#46775, #46983, #47035, #47175)
+- `archspec` was updated to v0.2.5 (#46503, #46958)
+- Fix path to Spack in `spack env depfile` makefile (#46966)
+- Fix `glibc` detection in Chinese locales (#47434)
+- Fix pickle round-trip of specs propagating variants (#47351)
+- Fix a bug where concurrent spack install commands would not always update explicits correctly
+  (#47358)
+- Fix a bug where autopush would run before all post install hooks modifying the install prefix
+  had run (#47329)
+- Fix `spack find -u` (#47102)
+- Fix a bug where sometimes the wrong Python interpreter was used for build dependencies such as
+  `py-setuptools` (#46980)
+- Fix default config errors found by `spack audit externals` (#47308)
+- Fix duplicate printing of external roots in installer (#44917)
+- Fix modules schema in `compilers.yaml` (#47197)
+- Reduce the size of generated YAML for Gitlab CI (#44995)
+- Handle missing metadata file gracefully in bootstrap (#47278)
+- Show underlying errors on fetch failure (#45714)
+- Recognize `.` and `..` as paths instead of names in buildcache commands (#47105)
+- Documentation and style (#46991, #47107, #47110, #47111, #47346, #47307, #47309, #47328, #47160,
+  #47402, #47557, #46709, #47080)
+- Tests and CI fixes (#47165, #46711)
+
+## Package updates
+- ffmpeg: fix hash of patch (#45574)
+
+# v0.22.2 (2024-09-21)
+
+## Bugfixes
+- Forward compatibility with Spack 0.23 packages with language dependencies (#45205, #45191)
+- Forward compatibility with `urllib` from Python 3.12.6+ (#46453, #46483)
+- Bump vendored `archspec` for better aarch64 support (#45721, #46445)
+- Support macOS Sequoia (#45018, #45127)
+- Fix regression in `{variants.X}` and `{variants.X.value}` format strings (#46206)
+- Ensure shell escaping of environment variable values in load and activate commands (#42780)
+- Fix an issue where `spec[pkg]` considers specs outside the current DAG (#45090)
+- Do not halt concretization on unknown variants in externals (#45326)
+- Improve validation of `develop` config section (#46485)
+- Explicitly disable `ccache` if turned off in config, to avoid cache pollution (#45275)
+- Improve backwards compatibility in `include_concrete` (#45766)
+- Fix issue where package tags were sometimes repeated (#45160)
+- Make `setup-env.sh` "sourced only" by dropping execution bits (#45641)
+- Make certain source/binary fetch errors recoverable instead of a hard error (#45683)
+- Remove debug statements in package hash computation (#45235)
+- Remove redundant clingo warnings (#45269)
+- Remove hard-coded layout version (#45645)
+- Do not initialize previous store state in `use_store` (#45268)
+- Docs improvements (#46475)
+
+## Package updates
+- `chapel` major update (#42197, #44931, #45304)
+
+# v0.22.1 (2024-07-04)
+
+## Bugfixes
+- Fix reuse of externals on Linux (#44316)
+- Ensure parent gcc-runtime version >= child (#44834, #44870)
+- Ensure the latest gcc-runtime is rpath'ed when multiple exist among link deps (#44219)
+- Improve version detection of glibc (#44154)
+- Improve heuristics for solver (#44893, #44976, #45023)
+- Make strong preferences override reuse (#44373)
+- Reduce verbosity when C compiler is missing (#44182)
+- Make missing ccache executable an error when required (#44740)
+- Make every environment view containing `python` a `venv` (#44382)
+- Fix external detection for compilers with os but no target (#44156)
+- Fix version optimization for roots (#44272)
+- Handle common implementations of pagination of tags in OCI build caches (#43136)
+- Apply fetched patches to develop specs (#44950)
+- Avoid Windows wrappers for filesystem utilities on non-Windows (#44126)
+- Fix issue with long filenames in build caches on Windows (#43851)
+- Fix formatting issue in `spack audit` (#45045)
+- CI fixes (#44582, #43965, #43967, #44279, #44213)
+
+## Package updates
+- protobuf: fix 3.4:3.21 patch checksum (#44443)
+- protobuf: update hash for patch needed when="@3.4:3.21" (#44210)
+- git: bump v2.39 to 2.45; deprecate unsafe versions (#44248)
+- gcc: use -rpath {rpath_dir} not -rpath={rpath dir} (#44315)
+- Remove mesa18 and libosmesa (#44264)
+- Enforce consistency of `gl` providers (#44307)
+- Require libiconv for iconv (#44335, #45026).
+  Notice that glibc/musl also provide iconv, but are not guaranteed to be
+  complete. Set `packages:iconv:require:[glibc]` to restore the old behavior.
+- py-matplotlib: qualify when to do a post install (#44191)
+- rust: fix v1.78.0 instructions (#44127)
+- suite-sparse: improve setting of the `libs` property (#44214)
+- netlib-lapack: provide blas and lapack together (#44981)
+
+
+# v0.22.0 (2024-05-12)
+
+`v0.22.0` is a major feature release.
+
+## Features in this release
+
+1. **Compiler dependencies**
+
+    We are in the process of making compilers proper dependencies in Spack, and a number
+    of changes in `v0.22` support that effort. You may notice nodes in your dependency
+    graphs for compiler runtime libraries like `gcc-runtime` or `libgfortran`, and you
+    may notice that Spack graphs now include `libc`. We've also begun moving compiler
+    configuration from `compilers.yaml` to `packages.yaml` to make it consistent with
+    other externals. We are trying to do this with the least disruption possible, so
+    your existing `compilers.yaml` files should still work. We expect to be done with
+    this transition by the `v0.23` release in November.
+
+    * #41104: Packages compiled with `%gcc` on Linux, macOS and FreeBSD now depend on a
+      new package `gcc-runtime`, which contains a copy of the shared compiler runtime
+      libraries. This enables gcc runtime libraries to be installed and relocated when
+      using a build cache. When building minimal Spack-generated container images it is
+      no longer necessary to install libgfortran, libgomp etc. using the system package
+      manager.
+
+    * #42062: Packages compiled with `%oneapi` now depend on a new package
+      `intel-oneapi-runtime`. This is similar to `gcc-runtime`, and the runtimes can
+      provide virtuals and compilers can inject dependencies on virtuals into compiled
+      packages. This allows us to model library soname compatibility and allows
+      compilers like `%oneapi` to provide virtuals like `sycl` (which can also be
+      provided by standalone libraries). Note that until we have an agreement in place
+      with intel, Intel packages are marked `redistribute(source=False, binary=False)`
+      and must be downloaded outside of Spack.
+
+    * #43272: changes to the optimization criteria of the solver improve the hit-rate of
+      buildcaches by a fair amount. The solver more relaxed compatibility rules and will
+      not try to strictly match compilers or targets of reused specs. Users can still
+      enforce the previous strict behavior with `require:` sections in `packages.yaml`.
+      Note that to enforce correct linking, Spack will *not* reuse old `%gcc` and
+      `%oneapi` specs that do not have the runtime libraries as a dependency.
+
+    * #43539: Spack will reuse specs built with compilers that are *not* explicitly
+      configured in `compilers.yaml`. Because we can now keep runtime libraries in build
+      cache, we do not require you to also have a local configured compiler to *use* the
+      runtime libraries. This improves reuse in buildcaches and avoids conflicts with OS
+      updates that happen underneath Spack.
+
+    * #43190: binary compatibility on `linux` is now based on the `libc` version,
+      instead of on the `os` tag. Spack builds now detect the host `libc` (`glibc` or
+      `musl`) and add it as an implicit external node in the dependency graph. Binaries
+      with a `libc` with the same name and a version less than or equal to that of the
+      detected `libc` can be reused. This is only on `linux`, not `macos` or `Windows`.
+
+    * #43464: each package that can provide a compiler is now detectable using `spack
+      external find`. External packages defining compiler paths are effectively used as
+      compilers, and `spack external find -t compiler` can be used as a substitute for
+      `spack compiler find`. More details on this transition are in
+      [the docs](https://spack.readthedocs.io/en/latest/getting_started.html#manual-compiler-configuration)
+
+2. **Improved `spack find` UI for Environments**
+
+   If you're working in an enviroment, you likely care about:
+
+   * What are the roots
+   * Which ones are installed / not installed
+   * What's been added that still needs to be concretized
+
+    We've tweaked `spack find` in environments to show this information much more
+    clearly. Installation status is shown next to each root, so you can see what is
+    installed. Roots are also shown in bold in the list of installed packages. There is
+    also a new option for `spack find -r` / `--only-roots` that will only show env
+    roots, if you don't want to look at all the installed specs.
+
+    More details in #42334.
+
+3. **Improved command-line string quoting**
+
+   We are making some breaking changes to how Spack parses specs on the CLI in order to
+   respect shell quoting instead of trying to fight it. If you (sadly) had to write
+   something like this on the command line:
+
+    ```
+    spack install zlib cflags=\"-O2 -g\"
+    ```
+
+    That will now result in an error, but you can now write what you probably expected
+    to work in the first place:
+
+    ```
+    spack install zlib cflags="-O2 -g"
+    ```
+
+    Quoted can also now include special characters, so you can supply flags like:
+
+    ```
+    spack intall zlib ldflags='-Wl,-rpath=$ORIGIN/_libs'
+    ```
+
+    To reduce ambiguity in parsing, we now require that you *not* put spaces around `=`
+    and `==` when for flags or variants. This would not have broken before but will now
+    result in an error:
+
+    ```
+    spack install zlib cflags = "-O2 -g"
+    ```
+
+    More details and discussion in #30634.
+
+4. **Revert default `spack install` behavior to `--reuse`**
+
+   We changed the default concretizer behavior from `--reuse` to `--reuse-deps` in
+   #30990 (in `v0.20`), which meant that *every* `spack install` invocation would
+   attempt to build a new version of the requested package / any environment roots.
+   While this is a common ask for *upgrading* and for *developer* workflows, we don't
+   think it should be the default for a package manager.
+
+   We are going to try to stick to this policy:
+   1. Prioritize reuse and build as little as possible by default.
+   2. Only upgrade or install duplicates if they are explicitly asked for, or if there
+      is a known security issue that necessitates an upgrade.
+
+   With the install command you now have three options:
+
+   * `--reuse` (default): reuse as many existing installations as possible.
+   * `--reuse-deps` / `--fresh-roots`: upgrade (freshen) roots but reuse dependencies if possible.
+   * `--fresh`: install fresh versions of requested packages (roots) and their dependencies.
+
+   We've also introduced `--fresh-roots` as an alias for `--reuse-deps` to make it more clear
+   that it may give you fresh versions. More details in #41302 and #43988.
+
+5. **More control over reused specs**
+
+   You can now control which packages to reuse and how. There is a new
+   `concretizer:reuse` config option, which accepts the following properties:
+
+   - `roots`: `true` to reuse roots, `false` to reuse just dependencies
+   - `exclude`: list of constraints used to select which specs *not* to reuse
+   - `include`: list of constraints used to select which specs *to* reuse
+   - `from`: list of sources for reused specs (some combination of `local`,
+     `buildcache`, or `external`)
+
+   For example, to reuse only specs compiled with GCC, you could write:
+
+   ```yaml
+   concretizer:
+      reuse:
+        roots: true
+        include:
+        - "%gcc"
+   ```
+
+   Or, if `openmpi` must be used from externals, and it must be the only external used:
+
+   ```yaml
+   concretizer:
+     reuse:
+       roots: true
+       from:
+       - type: local
+         exclude: ["openmpi"]
+       - type: buildcache
+         exclude: ["openmpi"]
+       - type: external
+         include: ["openmpi"]
+   ```
+
+6. **New `redistribute()` directive**
+
+   Some packages can't be redistributed in source or binary form. We need an explicit
+   way to say that in a package.
+
+   Now there is a `redistribute()` directive so that package authors can write:
+
+   ```python
+   class MyPackage(Package):
+       redistribute(source=False, binary=False)
+   ```
+
+   Like other directives, this works with `when=`:
+
+   ```python
+   class MyPackage(Package):
+       # 12.0 and higher are proprietary
+       redistribute(source=False, binary=False, when="@12.0:")
+
+       # can't redistribute when we depend on some proprietary dependency
+       redistribute(source=False, binary=False, when="^proprietary-dependency")
+   ```
+
+    More in #20185.
+
+7. **New `conflict:` and `prefer:` syntax for package preferences**
+
+   Previously, you could express conflicts and preferences in `packages.yaml` through
+   some contortions with `require:`:
+
+    ```yaml
+    packages:
+      zlib-ng:
+        require:
+        - one_of: ["%clang", "@:"]   # conflict on %clang
+        - any_of: ["+shared", "@:"]  # strong preference for +shared
+    ```
+
+    You can now use `require:` and `prefer:` for a much more readable configuration:
+
+    ```yaml
+    packages:
+      zlib-ng:
+        conflict:
+        - "%clang"
+        prefer:
+        - "+shared"
+    ```
+
+    See [the documentation](https://spack.readthedocs.io/en/latest/packages_yaml.html#conflicts-and-strong-preferences)
+    and #41832 for more details.
+
+8. **`include_concrete` in environments**
+
+   You may want to build on the *concrete* contents of another environment without
+   changing that environment.  You can now include the concrete specs from another
+   environment's `spack.lock` with `include_concrete`:
+
+   ```yaml
+      spack:
+        specs: []
+        concretizer:
+            unify: true
+        include_concrete:
+        - /path/to/environment1
+        - /path/to/environment2
+   ```
+
+   Now, when *this* environment is concretized, it will bring in the already concrete
+   specs from `environment1` and `environment2`, and build on top of them without
+   changing them. This is useful if you have phased deployments, where old deployments
+   should not be modified but you want to use as many of them as possible. More details
+   in #33768.
+
+9. **`python-venv` isolation**
+
+   Spack has unique requirements for Python because it:
+    1. installs every package in its own independent directory, and
+    2. allows users to register *external* python installations.
+
+   External installations may contain their own installed packages that can interfere
+   with Spack installations, and some distributions (Debian and Ubuntu) even change the
+   `sysconfig` in ways that alter the installation layout of installed Python packages
+   (e.g., with the addition of a `/local` prefix on Debian or Ubuntu). To isolate Spack
+   from these and other issues, we now insert a small `python-venv` package in between
+   `python` and packages that need to install Python code. This isolates Spack's build
+   environment, isolates Spack from any issues with an external python, and resolves a
+   large number of issues we've had with Python installations.
+
+   See #40773 for further details.
+
+## New commands, options, and directives
+
+* Allow packages to be pushed to build cache after install from source (#42423)
+* `spack develop`: stage build artifacts in same root as non-dev builds #41373
+  * Don't delete `spack develop` build artifacts after install (#43424)
+* `spack find`: add options for local/upstream only (#42999)
+* `spack logs`: print log files for packages (either partially built or installed) (#42202)
+* `patch`: support reversing patches (#43040)
+* `develop`: Add -b/--build-directory option to set build_directory package attribute (#39606)
+* `spack list`: add `--namesapce` / `--repo` option (#41948)
+* directives: add `checked_by` field to `license()`, add some license checks
+* `spack gc`: add options for environments and build dependencies (#41731)
+* Add `--create` to `spack env activate` (#40896)
+
+## Performance improvements
+
+* environment.py: fix excessive re-reads (#43746)
+* ruamel yaml: fix quadratic complexity bug  (#43745)
+* Refactor to improve `spec format` speed (#43712)
+* Do not acquire a write lock on the env post install if no views (#43505)
+* asp.py: fewer calls to `spec.copy()` (#43715)
+* spec.py: early return in `__str__`
+* avoid `jinja2` import at startup unless needed (#43237)
+
+## Other new features of note
+
+* `archspec`: update to `v0.2.4`: support for Windows, bugfixes for `neoverse-v1` and
+  `neoverse-v2` detection.
+* `spack config get`/`blame`: with no args, show entire config
+* `spack env create <env>`: dir if dir-like (#44024)
+* ASP-based solver: update os compatibility for macOS (#43862)
+* Add handling of custom ssl certs in urllib ops (#42953)
+* Add ability to rename environments (#43296)
+* Add config option and compiler support to reuse across OS's (#42693)
+* Support for prereleases (#43140)
+* Only reuse externals when configured (#41707)
+* Environments: Add support for including views (#42250)
+
+## Binary caches
+* Build cache: make signed/unsigned a mirror property (#41507)
+* tools stack
+
+## Removals, deprecations, and syntax changes
+* remove `dpcpp` compiler and package (#43418)
+* spack load: remove --only argument (#42120)
+
+## Notable Bugfixes
+* repo.py: drop deleted packages from provider cache (#43779)
+* Allow `+` in module file names (#41999)
+* `cmd/python`: use runpy to allow multiprocessing in scripts (#41789)
+* Show extension commands with spack -h (#41726)
+* Support environment variable expansion inside module projections (#42917)
+* Alert user to failed concretizations (#42655)
+* shell: fix zsh color formatting for PS1 in environments (#39497)
+* spack mirror create --all: include patches (#41579)
+
+## Spack community stats
+
+* 7,994 total packages; 525 since `v0.21.0`
+    * 178 new Python packages, 5 new R packages
+* 358 people contributed to this release
+    * 344 committers to packages
+    * 45 committers to core
+
+
 # v0.21.2 (2024-03-01)
 
 ## Bugfixes
@@ -27,7 +448,7 @@
 - spack graph: fix coloring with environments (#41240)
 - spack info: sort variants in --variants-by-name (#41389)
 - Spec.format: error on old style format strings (#41934)
-- ASP-based solver: 
+- ASP-based solver:
   - fix infinite recursion when computing concretization errors (#41061)
   - don't error for type mismatch on preferences (#41138)
   - don't emit spurious debug output (#41218)

etc/spack/defaults/concretizer.yaml

@@ -42,8 +42,8 @@ concretizer:
     # "minimal": allows the duplication of 'build-tools' nodes only (e.g. py-setuptools, cmake etc.)
     # "full" (experimental): allows separation of the entire build-tool stack (e.g. the entire "cmake" subDAG)
     strategy: minimal
-  # Option to specify compatiblity between operating systems for reuse of compilers and packages
-  # Specified as a key: [list] where the key is the os that is being targeted, and the list contains the OS's 
-  # it can reuse. Note this is a directional compatibility so mutual compatibility between two OS's 
+  # Option to specify compatibility between operating systems for reuse of compilers and packages
+  # Specified as a key: [list] where the key is the os that is being targeted, and the list contains the OS's
+  # it can reuse. Note this is a directional compatibility so mutual compatibility between two OS's
   # requires two entries i.e. os_compatible: {sonoma: [monterey], monterey: [sonoma]}
   os_compatible: {}

etc/spack/defaults/cray/packages.yaml

@@ -1,19 +0,0 @@
-# -------------------------------------------------------------------------
-# This file controls default concretization preferences for Spack.
-#
-# Settings here are versioned with Spack and are intended to provide
-# sensible defaults out of the box. Spack maintainers should edit this
-# file to keep it current.
-#
-# Users can override these settings by editing the following files.
-#
-# Per-spack-instance settings (overrides defaults):
-#   $SPACK_ROOT/etc/spack/packages.yaml
-#
-# Per-user settings (overrides default and site settings):
-#   ~/.spack/packages.yaml
-# -------------------------------------------------------------------------
-packages:
-  all:
-    providers:
-      iconv: [glibc, musl, libiconv]

etc/spack/defaults/linux/packages.yaml

@@ -1,19 +1,3 @@
-# -------------------------------------------------------------------------
-# This file controls default concretization preferences for Spack.
-#
-# Settings here are versioned with Spack and are intended to provide
-# sensible defaults out of the box. Spack maintainers should edit this
-# file to keep it current.
-#
-# Users can override these settings by editing the following files.
-#
-# Per-spack-instance settings (overrides defaults):
-#   $SPACK_ROOT/etc/spack/packages.yaml
-#
-# Per-user settings (overrides default and site settings):
-#   ~/.spack/packages.yaml
-# -------------------------------------------------------------------------
 packages:
-  all:
-    providers:
-      iconv: [glibc, musl, libiconv]
+  iconv:
+    require: [libiconv]

etc/spack/defaults/packages.yaml

@@ -37,9 +37,9 @@ packages:
       jpeg: [libjpeg-turbo, libjpeg]
       lapack: [openblas, amdlibflame]
       libc: [glibc, musl]
-      libgfortran: [ gcc-runtime ]
+      libgfortran: [gcc-runtime]
       libglx: [mesa+glx]
-      libifcore: [ intel-oneapi-runtime ]
+      libifcore: [intel-oneapi-runtime]
       libllvm: [llvm]
       lua-lang: [lua, lua-luajit-openresty, lua-luajit]
       luajit: [lua-luajit-openresty, lua-luajit]

lib/spack/docs/build_systems/autotoolspackage.rst

@@ -147,15 +147,6 @@ example, the ``bash`` shell is used to run the ``autogen.sh`` script.
    def autoreconf(self, spec, prefix):
        which("bash")("autogen.sh")
 
-If the ``package.py`` has build instructions in a separate
-:ref:`builder class <multiple_build_systems>`, the signature for a phase changes slightly:
-
-.. code-block:: python
-
-   class AutotoolsBuilder(AutotoolsBuilder):
-      def autoreconf(self, pkg, spec, prefix):
-         which("bash")("autogen.sh")
-
 """""""""""""""""""""""""""""""""""""""
 patching configure or Makefile.in files
 """""""""""""""""""""""""""""""""""""""

lib/spack/docs/build_systems/inteloneapipackage.rst

@@ -25,7 +25,7 @@ use Spack to build packages with the tools.
 The Spack Python class ``IntelOneapiPackage`` is a base class that is
 used by ``IntelOneapiCompilers``, ``IntelOneapiMkl``,
 ``IntelOneapiTbb`` and other classes to implement the oneAPI
-packages. Search for ``oneAPI`` at `packages.spack.io <https://packages.spack.io>`_ for the full
+packages. Search for ``oneAPI`` at `<packages.spack.io>`_ for the full
 list of available oneAPI packages, or use::
 
   spack list -d oneAPI

lib/spack/docs/chain.rst

@@ -5,9 +5,9 @@
 
 .. chain:
 
-============================
-Chaining Spack Installations
-============================
+=============================================
+Chaining Spack Installations (upstreams.yaml)
+=============================================
 
 You can point your Spack installation to another installation to use any
 packages that are installed there. To register the other Spack instance,

lib/spack/docs/contribution_guide.rst

@@ -184,7 +184,7 @@ Style Tests
 
 Spack uses `Flake8 <http://flake8.pycqa.org/en/latest/>`_ to test for
 `PEP 8 <https://www.python.org/dev/peps/pep-0008/>`_ conformance and
-`mypy <https://mypy.readthedocs.io/en/stable/>` for type checking. PEP 8 is
+`mypy <https://mypy.readthedocs.io/en/stable/>`_ for type checking. PEP 8 is
 a series of style guides for Python that provide suggestions for everything
 from variable naming to indentation. In order to limit the number of PRs that
 were mostly style changes, we decided to enforce PEP 8 conformance. Your PR

lib/spack/docs/developer_guide.rst

@@ -716,27 +716,27 @@ Release branches
 ^^^^^^^^^^^^^^^^
 
 There are currently two types of Spack releases: :ref:`major releases
-<major-releases>` (``0.17.0``, ``0.18.0``, etc.) and :ref:`point releases
-<point-releases>` (``0.17.1``, ``0.17.2``, ``0.17.3``, etc.). Here is a
+<major-releases>` (``0.21.0``, ``0.22.0``, etc.) and :ref:`patch releases
+<patch-releases>` (``0.22.1``, ``0.22.2``, ``0.22.3``, etc.). Here is a
 diagram of how Spack release branches work::
 
-    o    branch: develop  (latest version, v0.19.0.dev0)
+    o    branch: develop  (latest version, v0.23.0.dev0)
     |
     o
-    | o  branch: releases/v0.18, tag: v0.18.1
+    | o  branch: releases/v0.22, tag: v0.22.1
     o |
-    | o  tag: v0.18.0
+    | o  tag: v0.22.0
     o |
     | o
     |/
     o
     |
     o
-    | o  branch: releases/v0.17, tag: v0.17.2
+    | o  branch: releases/v0.21, tag: v0.21.2
     o |
-    | o  tag: v0.17.1
+    | o  tag: v0.21.1
     o |
-    | o  tag: v0.17.0
+    | o  tag: v0.21.0
     o |
     | o
     |/
@@ -747,8 +747,8 @@ requests target ``develop``. The ``develop`` branch will report that its
 version is that of the next **major** release with a ``.dev0`` suffix.
 
 Each Spack release series also has a corresponding branch, e.g.
-``releases/v0.18`` has ``0.18.x`` versions of Spack, and
-``releases/v0.17`` has ``0.17.x`` versions. A major release is the first
+``releases/v0.22`` has ``v0.22.x`` versions of Spack, and
+``releases/v0.21`` has ``v0.21.x`` versions. A major release is the first
 tagged version on a release branch. Minor releases are back-ported from
 develop onto release branches. This is typically done by cherry-picking
 bugfix commits off of ``develop``.
@@ -778,27 +778,40 @@ for more details.
 Scheduling work for releases
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-We schedule work for releases by creating `GitHub projects
-<https://github.com/spack/spack/projects>`_. At any time, there may be
-several open release projects. For example, below are two releases (from
-some past version of the page linked above):
+We schedule work for **major releases** through `milestones
+<https://github.com/spack/spack/milestones>`_ and `GitHub Projects
+<https://github.com/spack/spack/projects>`_, while **patch releases** use `labels
+<https://github.com/spack/spack/labels>`_.
 
-.. image:: images/projects.png
+There is only one milestone open at a time. Its name corresponds to the next major version, for
+example ``v0.23``. Important issues and pull requests should be assigned to this milestone by
+core developers, so that they are not forgotten at the time of release. The milestone is closed
+when the release is made, and a new milestone is created for the next major release.
 
-This image shows one release in progress for ``0.15.1`` and another for
-``0.16.0``. Each of these releases has a project board containing issues
-and pull requests. GitHub shows a status bar with completed work in
-green, work in progress in purple, and work not started yet in gray, so
-it's fairly easy to see progress.
+Bug reports in GitHub issues are automatically labelled ``bug`` and ``triage``. Spack developers
+assign one of the labels ``impact-low``, ``impact-medium`` or ``impact-high``. This will make the
+issue appear in the `Triaged bugs <https://github.com/orgs/spack/projects/6>`_ project board.
+Important issues should be assigned to the next milestone as well, so they appear at the top of
+the project board.
 
-Spack's project boards are not firm commitments so we move work between
-releases frequently. If we need to make a release and some tasks are not
-yet done, we will simply move them to the next minor or major release, rather
-than delaying the release to complete them.
+Spack's milestones are not firm commitments so we move work between releases frequently. If we
+need to make a release and some tasks are not yet done, we will simply move them to the next major
+release milestone, rather than delaying the release to complete them.
 
-For more on using GitHub project boards, see `GitHub's documentation
-<https://docs.github.com/en/github/managing-your-work-on-github/about-project-boards>`_.
+^^^^^^^^^^^^^^^^^^^^^
+Backporting bug fixes
+^^^^^^^^^^^^^^^^^^^^^
 
+When a bug is fixed in the ``develop`` branch, it is often necessary to backport the fix to one
+(or more) of the ``release/vX.Y`` branches. Only the release manager is responsible for doing
+backports, but Spack maintainers are responsible for labelling pull requests (and issues if no bug
+fix is available yet) with ``vX.Y.Z`` labels. The label should correspond to the next patch version
+that the bug fix should be backported to.
+
+Backports are done publicly by the release manager using a pull request named ``Backports vX.Y.Z``.
+This pull request is opened from the ``backports/vX.Y.Z`` branch, targets the ``releases/vX.Y``
+branch and contains a (growing) list of cherry-picked commits from the ``develop`` branch.
+Typically there are one or two backport pull requests open at any given time.
 
 .. _major-releases:
 
@@ -806,25 +819,21 @@ For more on using GitHub project boards, see `GitHub's documentation
 Making major releases
 ^^^^^^^^^^^^^^^^^^^^^
 
-Assuming a project board has already been created and all required work
-completed, the steps to make the major release are:
+Assuming all required work from the milestone is completed, the steps to make the major release
+are:
 
-#. Create two new project boards:
+#. `Create a new milestone <https://github.com/spack/spack/milestones>`_ for the next major
+   release.
 
-   * One for the next major release
-   * One for the next point release
+#. `Create a new label <https://github.com/spack/spack/labels>`_ for the next patch release.
 
-#. Move any optional tasks that are not done to one of the new project boards.
-
-   In general, small bugfixes should go to the next point release. Major
-   features, refactors, and changes that could affect concretization should
-   go in the next major release.
+#. Move any optional tasks that are not done to the next milestone.
 
 #. Create a branch for the release, based on ``develop``:
 
    .. code-block:: console
 
-      $ git checkout -b releases/v0.15 develop
+      $ git checkout -b releases/v0.23 develop
 
    For a version ``vX.Y.Z``, the branch's name should be
    ``releases/vX.Y``. That is, you should create a ``releases/vX.Y``
@@ -860,8 +869,8 @@ completed, the steps to make the major release are:
 
    Create a pull request targeting the ``develop`` branch, bumping the major
    version in ``lib/spack/spack/__init__.py`` with a ``dev0`` release segment.
-   For instance when you have just released ``v0.15.0``, set the version
-   to ``(0, 16, 0, 'dev0')`` on ``develop``.
+   For instance when you have just released ``v0.23.0``, set the version
+   to ``(0, 24, 0, 'dev0')`` on ``develop``.
 
 #. Follow the steps in :ref:`publishing-releases`.
 
@@ -870,82 +879,52 @@ completed, the steps to make the major release are:
 #. Follow the steps in :ref:`announcing-releases`.
 
 
-.. _point-releases:
+.. _patch-releases:
 
 ^^^^^^^^^^^^^^^^^^^^^
-Making point releases
+Making patch releases
 ^^^^^^^^^^^^^^^^^^^^^
 
-Assuming a project board has already been created and all required work
-completed, the steps to make the point release are:
+To make the patch release process both efficient and transparent, we use a *backports pull request*
+which contains cherry-picked commits from the ``develop`` branch. The majority of the work is to
+cherry-pick the bug fixes, which ideally should be done as soon as they land on ``develop``:
+this ensures cherry-picking happens in order, and makes conflicts easier to resolve since the
+changes are fresh in the mind of the developer.
 
-#. Create a new project board for the next point release.
+The backports pull request is always titled ``Backports vX.Y.Z`` and is labelled ``backports``. It
+is opened from a branch named ``backports/vX.Y.Z`` and targets the ``releases/vX.Y`` branch.
 
-#. Move any optional tasks that are not done to the next project board.
+Whenever a pull request labelled ``vX.Y.Z`` is merged, cherry-pick the associated squashed commit
+on ``develop`` to the ``backports/vX.Y.Z`` branch. For pull requests that were rebased (or not
+squashed), cherry-pick each associated commit individually. Never force push to the
+``backports/vX.Y.Z`` branch.
 
-#. Check out the release branch (it should already exist).
+.. warning::
 
-    For the ``X.Y.Z`` release, the release branch is called ``releases/vX.Y``.
-    For ``v0.15.1``, you would check out ``releases/v0.15``:
+   Sometimes you may **still** get merge conflicts even if you have
+   cherry-picked all the commits in order. This generally means there
+   is some other intervening pull request that the one you're trying
+   to pick depends on. In these cases, you'll need to make a judgment
+   call regarding those pull requests.  Consider the number of affected
+   files and/or the resulting differences.
 
-   .. code-block:: console
+   1. If the changes are small, you might just cherry-pick it.
 
-      $ git checkout releases/v0.15
+   2. If the changes are large, then you may decide that this fix is not
+      worth including in a patch release, in which case you should remove
+      the label from the pull request. Remember that large, manual backports
+      are seldom the right choice for a patch release.
 
-#. If a pull request to the release branch named ``Backports vX.Y.Z`` is not already
-   in the project, create it. This pull request ought to be created as early as
-   possible when working on a release project, so that we can build the release
-   commits incrementally, and identify potential conflicts at an early stage.
+When all commits are cherry-picked in the ``backports/vX.Y.Z`` branch, make the patch
+release as follows:
 
-#. Cherry-pick each pull request in the ``Done`` column of the release
-   project board onto the ``Backports vX.Y.Z`` pull request.
+#. `Create a new label <https://github.com/spack/spack/labels>`_ ``vX.Y.{Z+1}`` for the next patch
+   release.
 
-   This is **usually** fairly simple since we squash the commits from the
-   vast majority of pull requests. That means there is only one commit
-   per pull request to cherry-pick. For example, `this pull request
-   <https://github.com/spack/spack/pull/15777>`_ has three commits, but
-   they were squashed into a single commit on merge. You can see the
-   commit that was created here:
+#. Replace the label ``vX.Y.Z`` with ``vX.Y.{Z+1}`` for all PRs and issues that are not done.
 
-   .. image:: images/pr-commit.png
-
-   You can easily cherry pick it like this (assuming you already have the
-   release branch checked out):
-
-   .. code-block:: console
-
-      $ git cherry-pick 7e46da7
-
-   For pull requests that were rebased (or not squashed), you'll need to
-   cherry-pick each associated commit individually.
-
-   .. warning::
-
-      It is important to cherry-pick commits in the order they happened,
-      otherwise you can get conflicts while cherry-picking. When
-      cherry-picking look at the merge date,
-      **not** the number of the pull request or the date it was opened.
-
-      Sometimes you may **still** get merge conflicts even if you have
-      cherry-picked all the commits in order. This generally means there
-      is some other intervening pull request that the one you're trying
-      to pick depends on. In these cases, you'll need to make a judgment
-      call regarding those pull requests.  Consider the number of affected
-      files and or the resulting differences.
-
-      1. If the dependency changes are small, you might just cherry-pick it,
-         too. If you do this, add the task to the release board.
-
-      2. If the changes are large, then you may decide that this fix is not
-         worth including in a point release, in which case you should remove
-         the task from the release project.
-
-      3. You can always decide to manually back-port the fix to the release
-         branch if neither of the above options makes sense, but this can
-         require a lot of work. It's seldom the right choice.
-
-#. When all the commits from the project board are cherry-picked into
-   the ``Backports vX.Y.Z`` pull request, you can push a commit to:
+#. Manually push a single commit with commit message ``Set version to vX.Y.Z`` to the
+   ``backports/vX.Y.Z`` branch, that both bumps the Spack version number and updates the changelog:
 
    1. Bump the version in ``lib/spack/spack/__init__.py``.
    2. Update ``CHANGELOG.md`` with a list of the changes.
@@ -954,20 +933,22 @@ completed, the steps to make the point release are:
    release branch. See `the changelog from 0.14.1
    <https://github.com/spack/spack/commit/ff0abb9838121522321df2a054d18e54b566b44a>`_.
 
-#. Merge the ``Backports vX.Y.Z`` PR with the **Rebase and merge** strategy. This
-   is needed to keep track in the release branch of all the commits that were
-   cherry-picked.
-
-#. Make sure CI passes on the release branch, including:
+#. Make sure CI passes on the **backports pull request**, including:
 
    * Regular unit tests
    * Build tests
    * The E4S pipeline at `gitlab.spack.io <https://gitlab.spack.io>`_
 
-   If CI does not pass, you'll need to figure out why, and make changes
-   to the release branch until it does. You can make more commits, modify
-   or remove cherry-picked commits, or cherry-pick **more** from
-   ``develop`` to make this happen.
+#. Merge the ``Backports vX.Y.Z`` PR with the **Rebase and merge** strategy. This
+   is needed to keep track in the release branch of all the commits that were
+   cherry-picked.
+
+#. Make sure CI passes on the last commit of the **release branch**.
+
+#. In the rare case you need to include additional commits in the patch release after the backports
+   PR is merged, it is best to delete the last commit ``Set version to vX.Y.Z`` from the release
+   branch with a single force push, open a new backports PR named ``Backports vX.Y.Z (2)``, and
+   repeat the process. Avoid repeated force pushes to the release branch.
 
 #. Follow the steps in :ref:`publishing-releases`.
 
@@ -1042,25 +1023,31 @@ Updating `releases/latest`
 
 If the new release is the **highest** Spack release yet, you should
 also tag it as ``releases/latest``. For example, suppose the highest
-release is currently ``0.15.3``:
+release is currently ``0.22.3``:
 
-* If you are releasing ``0.15.4`` or ``0.16.0``, then you should tag
-  it with ``releases/latest``, as these are higher than ``0.15.3``.
+* If you are releasing ``0.22.4`` or ``0.23.0``, then you should tag
+  it with ``releases/latest``, as these are higher than ``0.22.3``.
 
 * If you are making a new release of an **older** major version of
-  Spack, e.g. ``0.14.4``, then you should not tag it as
+  Spack, e.g. ``0.21.4``, then you should not tag it as
   ``releases/latest`` (as there are newer major versions).
 
-To tag ``releases/latest``, do this:
+To do so, first fetch the latest tag created on GitHub, since you may not have it locally:
 
 .. code-block:: console
 
-   $ git checkout releases/vX.Y     # vX.Y is the new release's branch
-   $ git tag --force releases/latest
-   $ git push --force --tags
+   $ git fetch --force git@github.com:spack/spack vX.Y.Z
 
-The ``--force`` argument to ``git tag`` makes ``git`` overwrite the existing
-``releases/latest`` tag with the new one.
+Then tag ``vX.Y.Z`` as ``releases/latest`` and push the individual tag to GitHub.
+
+.. code-block:: console
+
+   $ git tag --force releases/latest vX.Y.Z
+   $ git push --force git@github.com:spack/spack releases/latest
+
+The ``--force`` argument to ``git tag`` makes ``git`` overwrite the existing ``releases/latest``
+tag with the new one. Do **not** use the ``--tags`` flag when pushing, since this will push *all*
+local tags.
 
 
 .. _announcing-releases:

lib/spack/docs/getting_started.rst

@@ -35,7 +35,7 @@ A build matrix showing which packages are working on which systems is shown belo
       .. code-block:: console
 
          apt update
-         apt install build-essential ca-certificates coreutils curl environment-modules gfortran git gpg lsb-release python3 python3-distutils python3-venv unzip zip
+         apt install bzip2 ca-certificates file g++ gcc gfortran git gzip lsb-release patch python3 tar unzip xz-utils zstd
 
    .. tab-item:: RHEL
 
@@ -43,14 +43,14 @@ A build matrix showing which packages are working on which systems is shown belo
 
          dnf install epel-release
          dnf group install "Development Tools"
-         dnf install curl findutils gcc-gfortran gnupg2 hostname iproute redhat-lsb-core python3 python3-pip python3-setuptools unzip python3-boto3
+         dnf install gcc-gfortran redhat-lsb-core python3 unzip
 
    .. tab-item:: macOS Brew
 
       .. code-block:: console
 
          brew update
-         brew install curl gcc git gnupg zip
+         brew install gcc git zip
 
 ------------
 Installation

lib/spack/docs/index.rst

@@ -12,10 +12,6 @@
 Spack
 ===================
 
-.. epigraph::
-
-   `These are docs for the Spack package manager. For sphere packing, see` `pyspack <https://pyspack.readthedocs.io>`_.
-
 Spack is a package management tool designed to support multiple
 versions and configurations of software on a wide variety of platforms
 and environments.  It was designed for large supercomputing centers,

lib/spack/docs/packaging_guide.rst

@@ -2442,15 +2442,14 @@ with. For example, suppose that in the ``libdwarf`` package you write:
 
    depends_on("libelf@0.8")
 
-Now ``libdwarf`` will require ``libelf`` at *exactly* version ``0.8``.
-You can also specify a requirement for a particular variant or for
-specific compiler flags:
+Now ``libdwarf`` will require ``libelf`` in the range ``0.8``, which
+includes patch versions ``0.8.1``, ``0.8.2``, etc. Apart from version
+restrictions, you can also specify variants if this package requires
+optional features of the dependency.
 
 .. code-block:: python
 
-   depends_on("libelf@0.8+debug")
-   depends_on("libelf debug=True")
-   depends_on("libelf cppflags='-fPIC'")
+   depends_on("libelf@0.8 +parser +pic")
 
 Both users *and* package authors can use the same spec syntax to refer
 to different package configurations. Users use the spec syntax on the
@@ -2458,46 +2457,82 @@ command line to find installed packages or to install packages with
 particular constraints, and package authors can use specs to describe
 relationships between packages.
 
-^^^^^^^^^^^^^^
-Version ranges
-^^^^^^^^^^^^^^
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+Specifying backward and forward compatibility
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-Although some packages require a specific version for their dependencies,
-most can be built with a range of versions. For example, if you are
-writing a package for a legacy Python module that only works with Python
-2.4 through 2.6, this would look like:
+Packages are often compatible with a range of versions of their
+dependencies. This is typically referred to as backward and forward
+compatibility. Spack allows you to specify this in the ``depends_on``
+directive using version ranges.
+
+**Backwards compatibility** means that the package requires at least a
+certain version of its dependency:
 
 .. code-block:: python
 
-   depends_on("python@2.4:2.6")
+   depends_on("python@3.10:")
 
-Version ranges in Spack are *inclusive*, so ``2.4:2.6`` means any version
-greater than or equal to ``2.4`` and up to and including any ``2.6.x``. If
-you want to specify that a package works with any version of Python 3 (or
-higher), this would look like:
+In this case, the package requires Python 3.10 or newer.
+
+Commonly, packages drop support for older versions of a dependency as
+they release new versions. In Spack you can conveniently add every
+backward compatibility rule as a separate line:
 
 .. code-block:: python
 
-   depends_on("python@3:")
+   # backward compatibility with Python
+   depends_on("python@3.8:")
+   depends_on("python@3.9:", when="@1.2:")
+   depends_on("python@3.10:", when="@1.4:")
 
-Here we leave out the upper bound. If you want to say that a package
-requires Python 2, you can similarly leave out the lower bound:
+This means that in general we need Python 3.8 or newer; from version
+1.2 onwards we need Python 3.9 or newer; from version 1.4 onwards we
+need Python 3.10 or newer. Notice that it's fine to have overlapping
+ranges in the ``when`` clauses.
+
+**Forward compatibility** means that the package requires at most a
+certain version of its dependency. Forward compatibility rules are
+necessary when there are breaking changes in the dependency that the
+package cannot handle. In Spack we often add forward compatibility
+bounds only at the time a new, breaking version of a dependency is
+released. As with backward compatibility, it is typical to see a list
+of forward compatibility bounds in a package file as seperate lines:
 
 .. code-block:: python
 
-   depends_on("python@:2")
+   # forward compatibility with Python
+   depends_on("python@:3.12", when="@:1.10")
+   depends_on("python@:3.13", when="@:1.12")
 
-Notice that we didn't use ``@:3``. Version ranges are *inclusive*, so
-``@:3`` means "up to and including any 3.x version".
+Notice how the ``:`` now appears before the version number both in the
+dependency and in the ``when`` clause. This tells Spack that in general
+we need Python 3.13 or older up to version ``1.12.x``, and up to version
+``1.10.x`` we need Python 3.12 or older. Said differently, forward compatibility
+with Python 3.13 was added in version 1.11, while version 1.13 added forward
+compatibility with Python 3.14.
 
-You can also simply write
+Notice that a version range ``@:3.12`` includes *any* patch version
+number ``3.12.x``, which is often useful when specifying forward compatibility
+bounds.
+
+So far we have seen open-ended version ranges, which is by far the most
+common use case. It is also possible to specify both a lower and an upper bound
+on the version of a dependency, like this:
 
 .. code-block:: python
 
-   depends_on("python@2.7")
+   depends_on("python@3.10:3.12")
 
-to tell Spack that the package needs Python 2.7.x. This is equivalent to
-``@2.7:2.7``.
+There is short syntax to specify that a package is compatible with say any
+``3.x`` version:
+
+.. code-block:: python
+
+   depends_on("python@3")
+
+The above is equivalent to ``depends_on("python@3:3")``, which means at least
+Python version 3 and at most any version ``3.x.y``.
 
 In very rare cases, you may need to specify an exact version, for example
 if you need to distinguish between ``3.2`` and ``3.2.1``:

lib/spack/docs/repositories.rst

@@ -476,3 +476,9 @@ implemented using Python's built-in `sys.path
 :py:mod:`spack.repo` module implements a custom `Python importer
 <https://docs.python.org/2/library/imp.html>`_.
 
+.. warning::
+
+   The mechanism for extending packages is not yet extensively tested,
+   and extending packages across repositories imposes inter-repo
+   dependencies, which may be hard to manage.  Use this feature at your
+   own risk, but let us know if you have a use case for it.

lib/spack/docs/requirements.txt

@@ -4,9 +4,9 @@ sphinx_design==0.5.0
 sphinx-rtd-theme==2.0.0
 python-levenshtein==0.25.1
 docutils==0.20.1
-pygments==2.18.0
+pygments==2.17.2
 urllib3==2.2.1
-pytest==8.2.1
+pytest==8.2.0
 isort==5.13.2
 black==24.4.2
 flake8==7.0.0

lib/spack/external/__init__.py

@@ -18,7 +18,7 @@
 
 * Homepage: https://pypi.python.org/pypi/archspec
 * Usage: Labeling, comparison and detection of microarchitectures
-* Version: 0.2.4 (commit 48b92512b9ce203ded0ebd1ac41b42593e931f7c)
+* Version: 0.2.5 (commit 38ce485258ffc4fc6dd6688f8dc90cb269478c47)
 
 astunparse
 ----------------

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

@@ -47,7 +47,11 @@ def decorator(factory):
 
 
 def partial_uarch(
-    name: str = "", vendor: str = "", features: Optional[Set[str]] = None, generation: int = 0
+    name: str = "",
+    vendor: str = "",
+    features: Optional[Set[str]] = None,
+    generation: int = 0,
+    cpu_part: str = "",
 ) -> Microarchitecture:
     """Construct a partial microarchitecture, from information gathered during system scan."""
     return Microarchitecture(
@@ -57,6 +61,7 @@ def partial_uarch(
         features=features or set(),
         compilers={},
         generation=generation,
+        cpu_part=cpu_part,
     )
 
 
@@ -90,6 +95,7 @@ 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):
@@ -345,6 +351,10 @@ 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

@@ -2,9 +2,7 @@
 # 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
@@ -65,23 +63,31 @@ class Microarchitecture:
                 passed in as argument above.
             * versions: versions that support this micro-architecture.
 
-        generation (int): generation of the micro-architecture, if
-            relevant.
+        generation (int): generation of the micro-architecture, if relevant.
+        cpu_part (str): cpu part of the architecture, if relevant.
     """
 
-    # pylint: disable=too-many-arguments
+    # pylint: disable=too-many-arguments,too-many-instance-attributes
     #: Aliases for micro-architecture's features
     feature_aliases = FEATURE_ALIASES
 
-    def __init__(self, name, parents, vendor, features, compilers, generation=0):
+    def __init__(self, name, parents, vendor, features, compilers, generation=0, cpu_part=""):
         self.name = name
         self.parents = parents
         self.vendor = vendor
         self.features = features
         self.compilers = compilers
+        # Only relevant for PowerPC
         self.generation = generation
-        # Cache the ancestor computation
+        # Only relevant for AArch64
+        self.cpu_part = cpu_part
+
+        # Cache the "ancestor" computation
         self._ancestors = None
+        # Cache the "generic" computation
+        self._generic = None
+        # Cache the "family" computation
+        self._family = None
 
     @property
     def ancestors(self):
@@ -111,8 +117,12 @@ 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
         )
 
+    def __hash__(self):
+        return hash(self.name)
+
     @coerce_target_names
     def __ne__(self, other):
         return not self == other
@@ -143,7 +153,8 @@ 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}, {0.generation!r})"
+            "{0.features!r}, {0.compilers!r}, generation={0.generation!r}, "
+            "cpu_part={0.cpu_part!r})"
         )
         return fmt.format(self)
 
@@ -168,18 +179,22 @@ def __contains__(self, feature):
     @property
     def family(self):
         """Returns the architecture family a given target belongs to"""
-        roots = [x for x in [self] + self.ancestors if not x.ancestors]
-        msg = "a target is expected to belong to just one architecture family"
-        msg += f"[found {', '.join(str(x) for x in roots)}]"
-        assert len(roots) == 1, msg
+        if self._family is None:
+            roots = [x for x in [self] + self.ancestors if not x.ancestors]
+            msg = "a target is expected to belong to just one architecture family"
+            msg += f"[found {', '.join(str(x) for x in roots)}]"
+            assert len(roots) == 1, msg
+            self._family = roots.pop()
 
-        return roots.pop()
+        return self._family
 
     @property
     def generic(self):
         """Returns the best generic architecture that is compatible with self"""
-        generics = [x for x in [self] + self.ancestors if x.vendor == "generic"]
-        return max(generics, key=lambda x: len(x.ancestors))
+        if self._generic is None:
+            generics = [x for x in [self] + self.ancestors if x.vendor == "generic"]
+            self._generic = max(generics, key=lambda x: len(x.ancestors))
+        return self._generic
 
     def to_dict(self):
         """Returns a dictionary representation of this object."""
@@ -190,6 +205,7 @@ def to_dict(self):
             "generation": self.generation,
             "parents": [str(x) for x in self.parents],
             "compilers": self.compilers,
+            "cpupart": self.cpu_part,
         }
 
     @staticmethod
@@ -202,6 +218,7 @@ 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):
@@ -360,8 +377,11 @@ 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)
+        targets[name] = Microarchitecture(
+            name, parents, vendor, features, compilers, generation=generation, cpu_part=cpu_part
+        )
 
     known_targets = {}
     data = archspec.cpu.schema.TARGETS_JSON["microarchitectures"]

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

@@ -1482,7 +1482,6 @@
         "cldemote",
         "movdir64b",
         "movdiri",
-        "pdcm",
         "serialize",
         "waitpkg"
       ],
@@ -2225,14 +2224,96 @@
         ],
         "nvhpc": [
           {
-            "versions": "21.11:",
+            "versions": "21.11:23.8",
 	    "name": "zen3",
             "flags": "-tp {name}",
-	    "warnings": "zen4 is not fully supported by nvhpc yet, falling back to zen3"
+	    "warnings": "zen4 is not fully supported by nvhpc versions < 23.9, falling back to zen3"
+          },
+          {
+            "versions": "23.9:",
+            "flags": "-tp {name}"
           }
 	]
       }
     },
+    "zen5": {
+      "from": ["zen4"],
+      "vendor": "AuthenticAMD",
+      "features": [
+        "abm",
+        "aes",
+        "avx",
+        "avx2",
+        "avx512_bf16",
+        "avx512_bitalg",
+        "avx512bw",
+        "avx512cd",
+        "avx512dq",
+        "avx512f",
+        "avx512ifma",
+        "avx512vbmi",
+        "avx512_vbmi2",
+        "avx512vl",
+        "avx512_vnni",
+        "avx512_vp2intersect",
+        "avx512_vpopcntdq",
+        "avx_vnni",
+        "bmi1",
+        "bmi2",
+        "clflushopt",
+        "clwb",
+        "clzero",
+        "cppc",
+        "cx16",
+        "f16c",
+        "flush_l1d",
+        "fma",
+        "fsgsbase",
+        "gfni",
+        "ibrs_enhanced",
+        "mmx",
+        "movbe",
+        "movdir64b",
+        "movdiri",
+        "pclmulqdq",
+        "popcnt",
+        "rdseed",
+        "sse",
+        "sse2",
+        "sse4_1",
+        "sse4_2",
+        "sse4a",
+        "ssse3",
+        "tsc_adjust",
+        "vaes",
+        "vpclmulqdq",
+        "xsavec",
+        "xsaveopt"
+      ],
+      "compilers": {
+        "gcc": [
+          {
+            "versions": "14.1:",
+            "name": "znver5",
+            "flags": "-march={name} -mtune={name}"
+          }
+        ],
+        "aocc": [
+          {
+            "versions": "5.0:",
+            "name": "znver5",
+            "flags": "-march={name} -mtune={name}"
+          }
+        ],
+        "clang": [
+          {
+            "versions": "19.1:",
+            "name": "znver5",
+            "flags": "-march={name} -mtune={name}"
+          }
+        ]
+      }
+    },
     "ppc64": {
       "from": [],
       "vendor": "generic",
@@ -2711,7 +2792,8 @@
             "flags": "-mcpu=thunderx2t99"
           }
         ]
-      }
+      },
+      "cpupart": "0x0af"
     },
     "a64fx": {
       "from": ["armv8.2a"],
@@ -2779,7 +2861,8 @@
             "flags": "-march=armv8.2-a+crc+crypto+fp16+sve"
           }
         ]
-      }
+      },
+      "cpupart": "0x001"
     },
     "cortex_a72": {
       "from": ["aarch64"],
@@ -2816,7 +2899,8 @@
                   "flags" : "-mcpu=cortex-a72"
               }
           ]
-      }
+      },
+      "cpupart": "0xd08"
     },
     "neoverse_n1": {
       "from": ["cortex_a72", "armv8.2a"],
@@ -2837,8 +2921,7 @@
           "asimdrdm",
           "lrcpc",
           "dcpop",
-          "asimddp",
-          "ssbs"
+          "asimddp"
       ],
       "compilers" : {
           "gcc": [
@@ -2902,7 +2985,8 @@
                   "flags": "-tp {name}"
               }
           ]
-      }
+      },
+      "cpupart": "0xd0c"
     },
     "neoverse_v1": {
       "from": ["neoverse_n1", "armv8.4a"],
@@ -2926,8 +3010,6 @@
           "lrcpc",
           "dcpop",
           "sha3",
-          "sm3",
-          "sm4",
           "asimddp",
           "sha512",
           "sve",
@@ -2936,7 +3018,6 @@
           "uscat",
           "ilrcpc",
           "flagm",
-          "ssbs",
           "dcpodp",
           "svei8mm",
           "svebf16",
@@ -3004,7 +3085,7 @@
               },
               {
                   "versions": "11:",
-                  "flags" : "-march=armv8.4-a+sve+ssbs+fp16+bf16+crypto+i8mm+rng"
+                  "flags" : "-march=armv8.4-a+sve+fp16+bf16+crypto+i8mm+rng"
               },
               {
                   "versions": "12:",
@@ -3028,7 +3109,8 @@
                   "flags": "-tp {name}"
               }
           ]
-      }
+      },
+      "cpupart": "0xd40"
     },
     "neoverse_v2": {
       "from": ["neoverse_n1", "armv9.0a"],
@@ -3052,32 +3134,22 @@
 	  "lrcpc",
 	  "dcpop",
 	  "sha3",
-	  "sm3",
-	  "sm4",
 	  "asimddp",
 	  "sha512",
 	  "sve",
 	  "asimdfhm",
-	  "dit",
 	  "uscat",
 	  "ilrcpc",
 	  "flagm",
-	  "ssbs",
 	  "sb",
 	  "dcpodp",
 	  "sve2",
-	  "sveaes",
-	  "svepmull",
-	  "svebitperm",
-	  "svesha3",
-	  "svesm4",
 	  "flagm2",
 	  "frint",
 	  "svei8mm",
 	  "svebf16",
 	  "i8mm",
-	  "bf16",
-	  "dgh"
+	  "bf16"
       ],
       "compilers" : {
           "gcc": [
@@ -3102,15 +3174,19 @@
                   "flags" : "-march=armv8.5-a+sve -mtune=cortex-a76"
               },
               {
-                  "versions": "10.0:11.99",
+                  "versions": "10.0:11.3.99",
                   "flags" : "-march=armv8.5-a+sve+sve2+i8mm+bf16 -mtune=cortex-a77"
               },
+	      {
+                  "versions": "11.4:11.99",
+                  "flags" : "-mcpu=neoverse-v2"
+              },
               {
-                  "versions": "12.0:12.99",
+                  "versions": "12.0:12.2.99",
                   "flags" : "-march=armv9-a+i8mm+bf16 -mtune=cortex-a710"
               },
 	      {
-                  "versions": "13.0:",
+                  "versions": "12.3:",
                   "flags" : "-mcpu=neoverse-v2"
               }
           ],
@@ -3145,7 +3221,112 @@
                   "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",
+	  "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"],
@@ -3211,7 +3392,8 @@
             "flags" : "-mcpu=apple-m1"
           }
         ]
-      }
+      },
+      "cpupart": "0x022"
     },
     "m2": {
       "from": ["m1", "armv8.5a"],
@@ -3289,7 +3471,8 @@
             "flags" : "-mcpu=apple-m2"
           }
         ]
-      }
+      },
+      "cpupart": "0x032"
     },
     "arm": {
       "from": [],

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

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

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

@@ -18,9 +18,10 @@
 import threading
 import traceback
 from contextlib import contextmanager
+from multiprocessing.connection import Connection
 from threading import Thread
 from types import ModuleType
-from typing import Optional
+from typing import Callable, Optional
 
 import llnl.util.tty as tty
 
@@ -329,49 +330,6 @@ def close(self):
             self.file.close()
 
 
-class MultiProcessFd:
-    """Return an object which stores a file descriptor and can be passed as an
-    argument to a function run with ``multiprocessing.Process``, such that
-    the file descriptor is available in the subprocess."""
-
-    def __init__(self, fd):
-        self._connection = None
-        self._fd = None
-        if sys.version_info >= (3, 8):
-            self._connection = multiprocessing.connection.Connection(fd)
-        else:
-            self._fd = fd
-
-    @property
-    def fd(self):
-        if self._connection:
-            return self._connection._handle
-        else:
-            return self._fd
-
-    def close(self):
-        if self._connection:
-            self._connection.close()
-        else:
-            os.close(self._fd)
-
-
-def close_connection_and_file(multiprocess_fd, file):
-    # MultiprocessFd is intended to transmit a FD
-    # to a child process, this FD is then opened to a Python File object
-    # (using fdopen). In >= 3.8, MultiprocessFd encapsulates a
-    # multiprocessing.connection.Connection; Connection closes the FD
-    # when it is deleted, and prints a warning about duplicate closure if
-    # it is not explicitly closed. In < 3.8, MultiprocessFd encapsulates a
-    # simple FD; closing the FD here appears to conflict with
-    # closure of the File object (in < 3.8 that is). Therefore this needs
-    # to choose whether to close the File or the Connection.
-    if sys.version_info >= (3, 8):
-        multiprocess_fd.close()
-    else:
-        file.close()
-
-
 @contextmanager
 def replace_environment(env):
     """Replace the current environment (`os.environ`) with `env`.
@@ -529,22 +487,20 @@ def __enter__(self):
         # forcing debug output.
         self._saved_debug = tty._debug
 
-        # OS-level pipe for redirecting output to logger
-        read_fd, write_fd = os.pipe()
+        # Pipe for redirecting output to logger
+        read_fd, self.write_fd = multiprocessing.Pipe(duplex=False)
 
-        read_multiprocess_fd = MultiProcessFd(read_fd)
-
-        # Multiprocessing pipe for communication back from the daemon
+        # Pipe for communication back from the daemon
         # Currently only used to save echo value between uses
-        self.parent_pipe, child_pipe = multiprocessing.Pipe()
+        self.parent_pipe, child_pipe = multiprocessing.Pipe(duplex=False)
 
         # Sets a daemon that writes to file what it reads from a pipe
         try:
             # need to pass this b/c multiprocessing closes stdin in child.
-            input_multiprocess_fd = None
+            input_fd = None
             try:
                 if sys.stdin.isatty():
-                    input_multiprocess_fd = MultiProcessFd(os.dup(sys.stdin.fileno()))
+                    input_fd = Connection(os.dup(sys.stdin.fileno()))
             except BaseException:
                 # just don't forward input if this fails
                 pass
@@ -553,9 +509,9 @@ def __enter__(self):
                 self.process = multiprocessing.Process(
                     target=_writer_daemon,
                     args=(
-                        input_multiprocess_fd,
-                        read_multiprocess_fd,
-                        write_fd,
+                        input_fd,
+                        read_fd,
+                        self.write_fd,
                         self.echo,
                         self.log_file,
                         child_pipe,
@@ -566,9 +522,9 @@ def __enter__(self):
                 self.process.start()
 
         finally:
-            if input_multiprocess_fd:
-                input_multiprocess_fd.close()
-            read_multiprocess_fd.close()
+            if input_fd:
+                input_fd.close()
+            read_fd.close()
 
         # Flush immediately before redirecting so that anything buffered
         # goes to the original stream
@@ -586,9 +542,9 @@ def __enter__(self):
             self._saved_stderr = os.dup(sys.stderr.fileno())
 
             # redirect to the pipe we created above
-            os.dup2(write_fd, sys.stdout.fileno())
-            os.dup2(write_fd, sys.stderr.fileno())
-            os.close(write_fd)
+            os.dup2(self.write_fd.fileno(), sys.stdout.fileno())
+            os.dup2(self.write_fd.fileno(), sys.stderr.fileno())
+            self.write_fd.close()
 
         else:
             # Handle I/O the Python way. This won't redirect lower-level
@@ -601,7 +557,7 @@ def __enter__(self):
             self._saved_stderr = sys.stderr
 
             # create a file object for the pipe; redirect to it.
-            pipe_fd_out = os.fdopen(write_fd, "w")
+            pipe_fd_out = os.fdopen(self.write_fd.fileno(), "w", closefd=False)
             sys.stdout = pipe_fd_out
             sys.stderr = pipe_fd_out
 
@@ -637,6 +593,7 @@ def __exit__(self, exc_type, exc_val, exc_tb):
         else:
             sys.stdout = self._saved_stdout
             sys.stderr = self._saved_stderr
+            self.write_fd.close()
 
         # print log contents in parent if needed.
         if self.log_file.write_in_parent:
@@ -850,14 +807,14 @@ def force_echo(self):
 
 
 def _writer_daemon(
-    stdin_multiprocess_fd,
-    read_multiprocess_fd,
-    write_fd,
-    echo,
-    log_file_wrapper,
-    control_pipe,
-    filter_fn,
-):
+    stdin_fd: Optional[Connection],
+    read_fd: Connection,
+    write_fd: Connection,
+    echo: bool,
+    log_file_wrapper: FileWrapper,
+    control_fd: Connection,
+    filter_fn: Optional[Callable[[str], str]],
+) -> None:
     """Daemon used by ``log_output`` to write to a log file and to ``stdout``.
 
     The daemon receives output from the parent process and writes it both
@@ -894,43 +851,37 @@ def _writer_daemon(
     ``StringIO`` in the parent. This is mainly for testing.
 
     Arguments:
-        stdin_multiprocess_fd (int): input from the terminal
-        read_multiprocess_fd (int): pipe for reading from parent's redirected
-            stdout
-        echo (bool): initial echo setting -- controlled by user and
-            preserved across multiple writer daemons
-        log_file_wrapper (FileWrapper): file to log all output
-        control_pipe (Pipe): multiprocessing pipe on which to send control
-            information to the parent
-        filter_fn (callable, optional): function to filter each line of output
+        stdin_fd: optional input from the terminal
+        read_fd: pipe for reading from parent's redirected stdout
+        echo: initial echo setting -- controlled by user and preserved across multiple writer
+            daemons
+        log_file_wrapper: file to log all output
+        control_pipe: multiprocessing pipe on which to send control information to the parent
+        filter_fn: optional function to filter each line of output
 
     """
-    # If this process was forked, then it will inherit file descriptors from
-    # the parent process. This process depends on closing all instances of
-    # write_fd to terminate the reading loop, so we close the file descriptor
-    # here. Forking is the process spawning method everywhere except Mac OS
-    # for Python >= 3.8 and on Windows
-    if sys.version_info < (3, 8) or sys.platform != "darwin":
-        os.close(write_fd)
+    # This process depends on closing all instances of write_pipe to terminate the reading loop
+    write_fd.close()
 
     # 1. Use line buffering (3rd param = 1) since Python 3 has a bug
     # that prevents unbuffered text I/O.
     # 2. Python 3.x before 3.7 does not open with UTF-8 encoding by default
-    in_pipe = os.fdopen(read_multiprocess_fd.fd, "r", 1, encoding="utf-8")
+    # 3. closefd=False because Connection has "ownership"
+    read_file = os.fdopen(read_fd.fileno(), "r", 1, encoding="utf-8", closefd=False)
 
-    if stdin_multiprocess_fd:
-        stdin = os.fdopen(stdin_multiprocess_fd.fd)
+    if stdin_fd:
+        stdin_file = os.fdopen(stdin_fd.fileno(), closefd=False)
     else:
-        stdin = None
+        stdin_file = None
 
     # list of streams to select from
-    istreams = [in_pipe, stdin] if stdin else [in_pipe]
+    istreams = [read_file, stdin_file] if stdin_file else [read_file]
     force_echo = False  # parent can force echo for certain output
 
     log_file = log_file_wrapper.unwrap()
 
     try:
-        with keyboard_input(stdin) as kb:
+        with keyboard_input(stdin_file) as kb:
             while True:
                 # fix the terminal settings if we recently came to
                 # the foreground
@@ -943,12 +894,12 @@ def _writer_daemon(
                 # Allow user to toggle echo with 'v' key.
                 # Currently ignores other chars.
                 # only read stdin if we're in the foreground
-                if stdin in rlist and not _is_background_tty(stdin):
+                if stdin_file and stdin_file in rlist and not _is_background_tty(stdin_file):
                     # it's possible to be backgrounded between the above
                     # check and the read, so we ignore SIGTTIN here.
                     with ignore_signal(signal.SIGTTIN):
                         try:
-                            if stdin.read(1) == "v":
+                            if stdin_file.read(1) == "v":
                                 echo = not echo
                         except IOError as e:
                             # If SIGTTIN is ignored, the system gives EIO
@@ -957,13 +908,13 @@ def _writer_daemon(
                             if e.errno != errno.EIO:
                                 raise
 
-                if in_pipe in rlist:
+                if read_file in rlist:
                     line_count = 0
                     try:
                         while line_count < 100:
                             # Handle output from the calling process.
                             try:
-                                line = _retry(in_pipe.readline)()
+                                line = _retry(read_file.readline)()
                             except UnicodeDecodeError:
                                 # installs like --test=root gpgme produce non-UTF8 logs
                                 line = "<line lost: output was not encoded as UTF-8>\n"
@@ -992,7 +943,7 @@ def _writer_daemon(
                                 if xoff in controls:
                                     force_echo = False
 
-                            if not _input_available(in_pipe):
+                            if not _input_available(read_file):
                                 break
                     finally:
                         if line_count > 0:
@@ -1007,14 +958,14 @@ def _writer_daemon(
     finally:
         # send written data back to parent if we used a StringIO
         if isinstance(log_file, io.StringIO):
-            control_pipe.send(log_file.getvalue())
+            control_fd.send(log_file.getvalue())
         log_file_wrapper.close()
-        close_connection_and_file(read_multiprocess_fd, in_pipe)
-        if stdin_multiprocess_fd:
-            close_connection_and_file(stdin_multiprocess_fd, stdin)
+        read_fd.close()
+        if stdin_fd:
+            stdin_fd.close()
 
         # send echo value back to the parent so it can be preserved.
-        control_pipe.send(echo)
+        control_fd.send(echo)
 
 
 def _retry(function):

lib/spack/spack/__init__.py

@@ -4,7 +4,7 @@
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 
 #: PEP440 canonical <major>.<minor>.<micro>.<devN> string
-__version__ = "0.23.0.dev0"
+__version__ = "0.22.5"
 spack_version = __version__
 
 

lib/spack/spack/audit.py

@@ -421,10 +421,6 @@ def _check_patch_urls(pkgs, error_cls):
         r"^https?://(?:patch-diff\.)?github(?:usercontent)?\.com/"
         r".+/.+/(?:commit|pull)/[a-fA-F0-9]+\.(?:patch|diff)"
     )
-    github_pull_commits_re = (
-        r"^https?://(?:patch-diff\.)?github(?:usercontent)?\.com/"
-        r".+/.+/pull/\d+/commits/[a-fA-F0-9]+\.(?:patch|diff)"
-    )
     # Only .diff URLs have stable/full hashes:
     # https://forum.gitlab.com/t/patches-with-full-index/29313
     gitlab_patch_url_re = (
@@ -440,24 +436,14 @@ def _check_patch_urls(pkgs, error_cls):
                 if not isinstance(patch, spack.patch.UrlPatch):
                     continue
 
-                if re.match(github_pull_commits_re, patch.url):
-                    url = re.sub(r"/pull/\d+/commits/", r"/commit/", patch.url)
-                    url = re.sub(r"^(.*)(?<!full_index=1)$", r"\1?full_index=1", url)
-                    errors.append(
-                        error_cls(
-                            f"patch URL in package {pkg_cls.name} "
-                            + "must not be a pull request commit; "
-                            + f"instead use {url}",
-                            [patch.url],
-                        )
-                    )
-                elif re.match(github_patch_url_re, patch.url):
+                if re.match(github_patch_url_re, patch.url):
                     full_index_arg = "?full_index=1"
                     if not patch.url.endswith(full_index_arg):
                         errors.append(
                             error_cls(
-                                f"patch URL in package {pkg_cls.name} "
-                                + f"must end with {full_index_arg}",
+                                "patch URL in package {0} must end with {1}".format(
+                                    pkg_cls.name, full_index_arg
+                                ),
                                 [patch.url],
                             )
                         )
@@ -465,7 +451,9 @@ def _check_patch_urls(pkgs, error_cls):
                     if not patch.url.endswith(".diff"):
                         errors.append(
                             error_cls(
-                                f"patch URL in package {pkg_cls.name} must end with .diff",
+                                "patch URL in package {0} must end with .diff".format(
+                                    pkg_cls.name
+                                ),
                                 [patch.url],
                             )
                         )
@@ -791,7 +779,7 @@ def check_virtual_with_variants(spec, msg):
                         return
                     error = error_cls(
                         f"{pkg_name}: {msg}",
-                        f"remove variants from '{spec}' in depends_on directive in {filename}",
+                        [f"remove variants from '{spec}' in depends_on directive in {filename}"],
                     )
                     errors.append(error)
 

lib/spack/spack/binary_distribution.py

@@ -23,7 +23,6 @@
 import warnings
 from contextlib import closing
 from typing import Dict, Iterable, List, NamedTuple, Optional, Set, Tuple
-from urllib.error import HTTPError, URLError
 
 import llnl.util.filesystem as fsys
 import llnl.util.lang
@@ -899,9 +898,8 @@ def url_read_method(url):
         try:
             _, _, spec_file = web_util.read_from_url(url)
             contents = codecs.getreader("utf-8")(spec_file).read()
-        except (URLError, web_util.SpackWebError) as url_err:
-            tty.error("Error reading specfile: {0}".format(url))
-            tty.error(url_err)
+        except web_util.SpackWebError as e:
+            tty.error(f"Error reading specfile: {url}: {e}")
         return contents
 
     try:
@@ -2041,21 +2039,17 @@ def try_direct_fetch(spec, mirrors=None):
         try:
             _, _, fs = web_util.read_from_url(buildcache_fetch_url_signed_json)
             specfile_is_signed = True
-        except (URLError, web_util.SpackWebError, HTTPError) as url_err:
+        except web_util.SpackWebError as e1:
             try:
                 _, _, fs = web_util.read_from_url(buildcache_fetch_url_json)
-            except (URLError, web_util.SpackWebError, HTTPError) as url_err_x:
+            except web_util.SpackWebError as e2:
                 tty.debug(
-                    "Did not find {0} on {1}".format(
-                        specfile_name, buildcache_fetch_url_signed_json
-                    ),
-                    url_err,
+                    f"Did not find {specfile_name} on {buildcache_fetch_url_signed_json}",
+                    e1,
                     level=2,
                 )
                 tty.debug(
-                    "Did not find {0} on {1}".format(specfile_name, buildcache_fetch_url_json),
-                    url_err_x,
-                    level=2,
+                    f"Did not find {specfile_name} on {buildcache_fetch_url_json}", e2, level=2
                 )
                 continue
         specfile_contents = codecs.getreader("utf-8")(fs).read()
@@ -2140,6 +2134,9 @@ def get_keys(install=False, trust=False, force=False, mirrors=None):
 
     for mirror in mirror_collection.values():
         fetch_url = mirror.fetch_url
+        # TODO: oci:// does not support signing.
+        if fetch_url.startswith("oci://"):
+            continue
         keys_url = url_util.join(
             fetch_url, BUILD_CACHE_RELATIVE_PATH, BUILD_CACHE_KEYS_RELATIVE_PATH
         )
@@ -2150,19 +2147,12 @@ def get_keys(install=False, trust=False, force=False, mirrors=None):
         try:
             _, _, json_file = web_util.read_from_url(keys_index)
             json_index = sjson.load(codecs.getreader("utf-8")(json_file))
-        except (URLError, web_util.SpackWebError) as url_err:
+        except web_util.SpackWebError as url_err:
             if web_util.url_exists(keys_index):
-                err_msg = [
-                    "Unable to find public keys in {0},",
-                    " caught exception attempting to read from {1}.",
-                ]
-
                 tty.error(
-                    "".join(err_msg).format(
-                        url_util.format(fetch_url), url_util.format(keys_index)
-                    )
+                    f"Unable to find public keys in {url_util.format(fetch_url)},"
+                    f" caught exception attempting to read from {url_util.format(keys_index)}."
                 )
-
                 tty.debug(url_err)
 
             continue
@@ -2442,7 +2432,7 @@ def get_remote_hash(self):
         url_index_hash = url_util.join(self.url, BUILD_CACHE_RELATIVE_PATH, "index.json.hash")
         try:
             response = self.urlopen(urllib.request.Request(url_index_hash, headers=self.headers))
-        except urllib.error.URLError:
+        except (TimeoutError, urllib.error.URLError):
             return None
 
         # Validate the hash
@@ -2464,7 +2454,7 @@ def conditional_fetch(self) -> FetchIndexResult:
 
         try:
             response = self.urlopen(urllib.request.Request(url_index, headers=self.headers))
-        except urllib.error.URLError as e:
+        except (TimeoutError, urllib.error.URLError) as e:
             raise FetchIndexError("Could not fetch index from {}".format(url_index), e) from e
 
         try:
@@ -2505,10 +2495,7 @@ def __init__(self, url, etag, urlopen=web_util.urlopen):
     def conditional_fetch(self) -> FetchIndexResult:
         # Just do a conditional fetch immediately
         url = url_util.join(self.url, BUILD_CACHE_RELATIVE_PATH, "index.json")
-        headers = {
-            "User-Agent": web_util.SPACK_USER_AGENT,
-            "If-None-Match": '"{}"'.format(self.etag),
-        }
+        headers = {"User-Agent": web_util.SPACK_USER_AGENT, "If-None-Match": f'"{self.etag}"'}
 
         try:
             response = self.urlopen(urllib.request.Request(url, headers=headers))
@@ -2516,14 +2503,14 @@ def conditional_fetch(self) -> FetchIndexResult:
             if e.getcode() == 304:
                 # Not modified; that means fresh.
                 return FetchIndexResult(etag=None, hash=None, data=None, fresh=True)
-            raise FetchIndexError("Could not fetch index {}".format(url), e) from e
-        except urllib.error.URLError as e:
-            raise FetchIndexError("Could not fetch index {}".format(url), e) from e
+            raise FetchIndexError(f"Could not fetch index {url}", e) from e
+        except (TimeoutError, urllib.error.URLError) as e:
+            raise FetchIndexError(f"Could not fetch index {url}", e) from e
 
         try:
             result = codecs.getreader("utf-8")(response).read()
         except ValueError as e:
-            raise FetchIndexError("Remote index {} is invalid".format(url), e) from e
+            raise FetchIndexError(f"Remote index {url} is invalid", e) from e
 
         headers = response.headers
         etag_header_value = headers.get("Etag", None) or headers.get("etag", None)
@@ -2554,21 +2541,19 @@ def conditional_fetch(self) -> FetchIndexResult:
                     headers={"Accept": "application/vnd.oci.image.manifest.v1+json"},
                 )
             )
-        except urllib.error.URLError as e:
-            raise FetchIndexError(
-                "Could not fetch manifest from {}".format(url_manifest), e
-            ) from e
+        except (TimeoutError, urllib.error.URLError) as e:
+            raise FetchIndexError(f"Could not fetch manifest from {url_manifest}", e) from e
 
         try:
             manifest = json.loads(response.read())
         except Exception as e:
-            raise FetchIndexError("Remote index {} is invalid".format(url_manifest), e) from e
+            raise FetchIndexError(f"Remote index {url_manifest} is invalid", e) from e
 
         # Get first blob hash, which should be the index.json
         try:
             index_digest = spack.oci.image.Digest.from_string(manifest["layers"][0]["digest"])
         except Exception as e:
-            raise FetchIndexError("Remote index {} is invalid".format(url_manifest), e) from e
+            raise FetchIndexError(f"Remote index {url_manifest} is invalid", e) from e
 
         # Fresh?
         if index_digest.digest == self.local_hash:

lib/spack/spack/bootstrap/core.py

@@ -597,7 +597,10 @@ def bootstrapping_sources(scope: Optional[str] = None):
         current = copy.copy(entry)
         metadata_dir = spack.util.path.canonicalize_path(entry["metadata"])
         metadata_yaml = os.path.join(metadata_dir, METADATA_YAML_FILENAME)
-        with open(metadata_yaml, encoding="utf-8") as stream:
-            current.update(spack.util.spack_yaml.load(stream))
-        list_of_sources.append(current)
+        try:
+            with open(metadata_yaml, encoding="utf-8") as stream:
+                current.update(spack.util.spack_yaml.load(stream))
+            list_of_sources.append(current)
+        except OSError:
+            pass
     return list_of_sources

lib/spack/spack/build_environment.py

@@ -43,7 +43,8 @@
 from collections import defaultdict
 from enum import Flag, auto
 from itertools import chain
-from typing import Dict, List, Set, Tuple
+from multiprocessing.connection import Connection
+from typing import Callable, Dict, List, Optional, Set, Tuple
 
 import llnl.util.tty as tty
 from llnl.string import plural
@@ -51,7 +52,6 @@
 from llnl.util.lang import dedupe, stable_partition
 from llnl.util.symlink import symlink
 from llnl.util.tty.color import cescape, colorize
-from llnl.util.tty.log import MultiProcessFd
 
 import spack.build_systems.cmake
 import spack.build_systems.meson
@@ -72,6 +72,7 @@
 import spack.store
 import spack.subprocess_context
 import spack.user_environment
+import spack.util.executable
 import spack.util.path
 import spack.util.pattern
 from spack import traverse
@@ -479,12 +480,12 @@ 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"):
-        ccache = Executable("ccache")
-        if not ccache:
-            raise RuntimeError("No ccache binary found in PATH")
-        env.set(SPACK_CCACHE_BINARY, 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")))
@@ -1144,18 +1145,60 @@ def get_cmake_prefix_path(pkg):
 
 
 def _setup_pkg_and_run(
-    serialized_pkg, function, kwargs, write_pipe, input_multiprocess_fd, jsfd1, jsfd2
+    serialized_pkg: "spack.subprocess_context.PackageInstallContext",
+    function: Callable,
+    kwargs: Dict,
+    write_pipe: Connection,
+    input_pipe: Optional[Connection],
+    jsfd1: Optional[Connection],
+    jsfd2: Optional[Connection],
 ):
+    """Main entry point in the child process for Spack builds.
+
+    ``_setup_pkg_and_run`` is called by the child process created in
+    ``start_build_process()``, and its main job is to run ``function()`` on behalf of
+    some Spack installation (see :ref:`spack.installer.PackageInstaller._install_task`).
+
+    The child process is passed a ``write_pipe``, on which it's expected to send one of
+    the following:
+
+    * ``StopPhase``: error raised by a build process indicating it's stopping at a
+      particular build phase.
+
+    * ``BaseException``: any exception raised by a child build process, which will be
+      wrapped in ``ChildError`` (which adds a bunch of debug info and log context) and
+      raised in the parent.
+
+    * The return value of ``function()``, which can be anything (except an exception).
+      This is returned to the caller.
+
+    Note: ``jsfd1`` and ``jsfd2`` are passed solely to ensure that the child process
+    does not close these file descriptors. Some ``multiprocessing`` backends will close
+    them automatically in the child if they are not passed at process creation time.
+
+    Arguments:
+        serialized_pkg: Spack package install context object (serialized form of the
+            package that we'll build in the child process).
+        function: function to call in the child process; serialized_pkg is passed to
+            this as the first argument.
+        kwargs: additional keyword arguments to pass to ``function()``.
+        write_pipe: multiprocessing ``Connection`` to the parent process, to which the
+            child *must* send a result (or an error) back to parent on.
+        input_multiprocess_fd: stdin from the parent (not passed currently on Windows)
+        jsfd1: gmake Jobserver file descriptor 1.
+        jsfd2: gmake Jobserver file descriptor 2.
+
+    """
+
     context: str = kwargs.get("context", "build")
 
     try:
-        # We are in the child process. Python sets sys.stdin to
-        # open(os.devnull) to prevent our process and its parent from
-        # simultaneously reading from the original stdin. But, we assume
-        # that the parent process is not going to read from it till we
-        # are done with the child, so we undo Python's precaution.
-        if input_multiprocess_fd is not None:
-            sys.stdin = os.fdopen(input_multiprocess_fd.fd)
+        # We are in the child process. Python sets sys.stdin to open(os.devnull) to prevent our
+        # process and its parent from simultaneously reading from the original stdin. But, we
+        # assume that the parent process is not going to read from it till we are done with the
+        # child, so we undo Python's precaution. closefd=False since Connection has ownership.
+        if input_pipe is not None:
+            sys.stdin = os.fdopen(input_pipe.fileno(), closefd=False)
 
         pkg = serialized_pkg.restore()
 
@@ -1171,13 +1214,14 @@ def _setup_pkg_and_run(
         # Do not create a full ChildError from this, it's not an error
         # it's a control statement.
         write_pipe.send(e)
-    except BaseException:
+    except BaseException as e:
         # catch ANYTHING that goes wrong in the child process
-        exc_type, exc, tb = sys.exc_info()
 
         # Need to unwind the traceback in the child because traceback
         # objects can't be sent to the parent.
-        tb_string = traceback.format_exc()
+        exc_type = type(e)
+        tb = e.__traceback__
+        tb_string = "".join(traceback.format_exception(exc_type, e, tb))
 
         # build up some context from the offending package so we can
         # show that, too.
@@ -1194,8 +1238,8 @@ def _setup_pkg_and_run(
         elif context == "test":
             logfile = os.path.join(pkg.test_suite.stage, pkg.test_suite.test_log_name(pkg.spec))
 
-        error_msg = str(exc)
-        if isinstance(exc, (spack.multimethod.NoSuchMethodError, AttributeError)):
+        error_msg = str(e)
+        if isinstance(e, (spack.multimethod.NoSuchMethodError, AttributeError)):
             process = "test the installation" if context == "test" else "build from sources"
             error_msg = (
                 "The '{}' package cannot find an attribute while trying to {}. "
@@ -1205,7 +1249,7 @@ def _setup_pkg_and_run(
                 "More information at https://spack.readthedocs.io/en/latest/packaging_guide.html#installation-procedure"
             ).format(pkg.name, process, context)
             error_msg = colorize("@*R{{{}}}".format(error_msg))
-            error_msg = "{}\n\n{}".format(str(exc), error_msg)
+            error_msg = "{}\n\n{}".format(str(e), error_msg)
 
         # make a pickleable exception to send to parent.
         msg = "%s: %s" % (exc_type.__name__, error_msg)
@@ -1223,8 +1267,8 @@ def _setup_pkg_and_run(
 
     finally:
         write_pipe.close()
-        if input_multiprocess_fd is not None:
-            input_multiprocess_fd.close()
+        if input_pipe is not None:
+            input_pipe.close()
 
 
 def start_build_process(pkg, function, kwargs):
@@ -1251,23 +1295,9 @@ def child_fun():
     If something goes wrong, the child process catches the error and
     passes it to the parent wrapped in a ChildError.  The parent is
     expected to handle (or re-raise) the ChildError.
-
-    This uses `multiprocessing.Process` to create the child process. The
-    mechanism used to create the process differs on different operating
-    systems and for different versions of Python. In some cases "fork"
-    is used (i.e. the "fork" system call) and some cases it starts an
-    entirely new Python interpreter process (in the docs this is referred
-    to as the "spawn" start method). Breaking it down by OS:
-
-    - Linux always uses fork.
-    - Mac OS uses fork before Python 3.8 and "spawn" for 3.8 and after.
-    - Windows always uses the "spawn" start method.
-
-    For more information on `multiprocessing` child process creation
-    mechanisms, see https://docs.python.org/3/library/multiprocessing.html#contexts-and-start-methods
     """
     read_pipe, write_pipe = multiprocessing.Pipe(duplex=False)
-    input_multiprocess_fd = None
+    input_fd = None
     jobserver_fd1 = None
     jobserver_fd2 = None
 
@@ -1276,14 +1306,13 @@ def child_fun():
     try:
         # Forward sys.stdin when appropriate, to allow toggling verbosity
         if sys.platform != "win32" and sys.stdin.isatty() and hasattr(sys.stdin, "fileno"):
-            input_fd = os.dup(sys.stdin.fileno())
-            input_multiprocess_fd = MultiProcessFd(input_fd)
+            input_fd = Connection(os.dup(sys.stdin.fileno()))
         mflags = os.environ.get("MAKEFLAGS", False)
         if mflags:
             m = re.search(r"--jobserver-[^=]*=(\d),(\d)", mflags)
             if m:
-                jobserver_fd1 = MultiProcessFd(int(m.group(1)))
-                jobserver_fd2 = MultiProcessFd(int(m.group(2)))
+                jobserver_fd1 = Connection(int(m.group(1)))
+                jobserver_fd2 = Connection(int(m.group(2)))
 
         p = multiprocessing.Process(
             target=_setup_pkg_and_run,
@@ -1292,7 +1321,7 @@ def child_fun():
                 function,
                 kwargs,
                 write_pipe,
-                input_multiprocess_fd,
+                input_fd,
                 jobserver_fd1,
                 jobserver_fd2,
             ),
@@ -1312,8 +1341,8 @@ def child_fun():
 
     finally:
         # Close the input stream in the parent process
-        if input_multiprocess_fd is not None:
-            input_multiprocess_fd.close()
+        if input_fd is not None:
+            input_fd.close()
 
     def exitcode_msg(p):
         typ = "exit" if p.exitcode >= 0 else "signal"

lib/spack/spack/build_systems/cuda.py

@@ -137,14 +137,11 @@ 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@:12.4")
         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@:12.4")
+        conflicts("%clang@16:", when="+cuda ^cuda@:12.3")
 
         # https://gist.github.com/ax3l/9489132#gistcomment-3860114
         conflicts("%gcc@10", when="+cuda ^cuda@:11.4.0")

lib/spack/spack/ci.py

@@ -22,6 +22,8 @@
 from urllib.parse import urlencode
 from urllib.request import HTTPHandler, Request, build_opener
 
+import ruamel.yaml
+
 import llnl.util.filesystem as fs
 import llnl.util.tty as tty
 from llnl.util.lang import memoized
@@ -1111,7 +1113,7 @@ 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) as err:
+        except (SpackError, HTTPError, URLError, TimeoutError) as err:
             tty.warn(f"Problem populating buildgroup: {err}")
     else:
         tty.warn("Unable to populate buildgroup without CDash credentials")
@@ -1310,8 +1312,11 @@ def main_script_replacements(cmd):
         if not rebuild_everything:
             sys.exit(1)
 
-    with open(output_file, "w") as outf:
-        outf.write(syaml.dump(sorted_output, default_flow_style=True))
+    # Minimize yaml output size through use of anchors
+    syaml.anchorify(sorted_output)
+
+    with open(output_file, "w") as f:
+        ruamel.yaml.YAML().dump(sorted_output, f)
 
 
 def _url_encode_string(input_string):
@@ -2095,7 +2100,7 @@ def read_broken_spec(broken_spec_url):
     """
     try:
         _, _, fs = web_util.read_from_url(broken_spec_url)
-    except (URLError, web_util.SpackWebError, HTTPError):
+    except web_util.SpackWebError:
         tty.warn(f"Unable to read broken spec from {broken_spec_url}")
         return None
 

lib/spack/spack/cmd/buildcache.py

@@ -813,7 +813,7 @@ def _push_oci(
 
     def extra_config(spec: Spec):
         spec_dict = spec.to_dict(hash=ht.dag_hash)
-        spec_dict["buildcache_layout_version"] = 1
+        spec_dict["buildcache_layout_version"] = bindist.CURRENT_BUILD_CACHE_LAYOUT_VERSION
         spec_dict["binary_cache_checksum"] = {
             "hash_algorithm": "sha256",
             "hash": checksums[spec.dag_hash()].compressed_digest.digest,

lib/spack/spack/cmd/commands.py

@@ -11,7 +11,6 @@
 from argparse import ArgumentParser, Namespace
 from typing import IO, Any, Callable, Dict, Iterable, List, Optional, Sequence, Set, Tuple, Union
 
-import llnl.util.filesystem as fs
 import llnl.util.tty as tty
 from llnl.util.argparsewriter import ArgparseRstWriter, ArgparseWriter, Command
 from llnl.util.tty.colify import colify
@@ -867,9 +866,6 @@ def _commands(parser: ArgumentParser, args: Namespace) -> None:
             prepend_header(args, f)
             formatter(args, f)
 
-        if args.update_completion:
-            fs.set_executable(args.update)
-
     else:
         prepend_header(args, sys.stdout)
         formatter(args, sys.stdout)

lib/spack/spack/cmd/common/arguments.py

@@ -661,34 +661,32 @@ def mirror_name_or_url(m):
     # accidentally to a dir in the current working directory.
 
     # If there's a \ or / in the name, it's interpreted as a path or url.
-    if "/" in m or "\\" in m:
+    if "/" in m or "\\" in m or m in (".", ".."):
         return spack.mirror.Mirror(m)
 
     # Otherwise, the named mirror is required to exist.
     try:
         return spack.mirror.require_mirror_name(m)
     except ValueError as e:
-        raise argparse.ArgumentTypeError(
-            str(e) + ". Did you mean {}?".format(os.path.join(".", m))
-        )
+        raise argparse.ArgumentTypeError(f"{e}. Did you mean {os.path.join('.', m)}?") from e
 
 
 def mirror_url(url):
     try:
         return spack.mirror.Mirror.from_url(url)
     except ValueError as e:
-        raise argparse.ArgumentTypeError(str(e))
+        raise argparse.ArgumentTypeError(str(e)) from e
 
 
 def mirror_directory(path):
     try:
         return spack.mirror.Mirror.from_local_path(path)
     except ValueError as e:
-        raise argparse.ArgumentTypeError(str(e))
+        raise argparse.ArgumentTypeError(str(e)) from e
 
 
 def mirror_name(name):
     try:
         return spack.mirror.require_mirror_name(name)
     except ValueError as e:
-        raise argparse.ArgumentTypeError(str(e))
+        raise argparse.ArgumentTypeError(str(e)) from e

lib/spack/spack/cmd/env.py

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

lib/spack/spack/cmd/find.py

@@ -169,9 +169,9 @@ def query_arguments(args):
     if (args.missing or args.only_missing) and not args.only_deprecated:
         installed.append(InstallStatuses.MISSING)
 
-    known = any
+    predicate_fn = None
     if args.unknown:
-        known = False
+        predicate_fn = lambda x: not spack.repo.PATH.exists(x.spec.name)
 
     explicit = any
     if args.explicit:
@@ -179,7 +179,7 @@ def query_arguments(args):
     if args.implicit:
         explicit = False
 
-    q_args = {"installed": installed, "known": known, "explicit": explicit}
+    q_args = {"installed": installed, "predicate_fn": predicate_fn, "explicit": explicit}
 
     install_tree = args.install_tree
     upstreams = spack.config.get("upstreams", {})

lib/spack/spack/cmd/install.py

@@ -61,7 +61,6 @@ def install_kwargs_from_args(args):
         "dependencies_use_cache": cache_opt(args.use_cache, dep_use_bc),
         "dependencies_cache_only": cache_opt(args.cache_only, dep_use_bc),
         "include_build_deps": args.include_build_deps,
-        "explicit": True,  # Use true as a default for install command
         "stop_at": args.until,
         "unsigned": args.unsigned,
         "install_deps": ("dependencies" in args.things_to_install),
@@ -473,6 +472,7 @@ def install_without_active_env(args, install_kwargs, reporter_factory):
             require_user_confirmation_for_overwrite(concrete_specs, args)
             install_kwargs["overwrite"] = [spec.dag_hash() for spec in concrete_specs]
 
-        installs = [(s.package, install_kwargs) for s in concrete_specs]
-        builder = PackageInstaller(installs)
+        installs = [s.package for s in concrete_specs]
+        install_kwargs["explicit"] = [s.dag_hash() for s in concrete_specs]
+        builder = PackageInstaller(installs, install_kwargs)
         builder.install()

lib/spack/spack/cmd/license.py

@@ -3,7 +3,6 @@
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 
-import datetime
 import os
 import re
 from collections import defaultdict
@@ -97,7 +96,7 @@ def list_files(args):
 OLD_LICENSE, SPDX_MISMATCH, GENERAL_MISMATCH = range(1, 4)
 
 #: Latest year that copyright applies. UPDATE THIS when bumping copyright.
-latest_year = datetime.date.today().year
+latest_year = 2024  # year of 0.22 release
 strict_date = r"Copyright 2013-%s" % latest_year
 
 #: regexes for valid license lines at tops of files

lib/spack/spack/cmd/mark.py

@@ -101,8 +101,9 @@ def do_mark(specs, explicit):
         specs (list): list of specs to be marked
         explicit (bool): whether to mark specs as explicitly installed
     """
-    for spec in specs:
-        spack.store.STORE.db.update_explicit(spec, explicit)
+    with spack.store.STORE.db.write_transaction():
+        for spec in specs:
+            spack.store.STORE.db.mark(spec, "explicit", explicit)
 
 
 def mark_specs(args, specs):

lib/spack/spack/cmd/modules/__init__.py

@@ -377,7 +377,10 @@ def refresh(module_type, specs, args):
 def modules_cmd(parser, args, module_type, callbacks=callbacks):
     # Qualifiers to be used when querying the db for specs
     constraint_qualifiers = {
-        "refresh": {"installed": True, "known": lambda x: not spack.repo.PATH.exists(x)}
+        "refresh": {
+            "installed": True,
+            "predicate_fn": lambda x: spack.repo.PATH.exists(x.spec.name),
+        }
     }
     query_args = constraint_qualifiers.get(args.subparser_name, {})
 

lib/spack/spack/cmd/uninstall.py

@@ -151,8 +151,7 @@ def is_installed(spec):
         key=lambda s: s.dag_hash(),
     )
 
-    with spack.store.STORE.db.read_transaction():
-        return [spec for spec in specs if is_installed(spec)]
+    return [spec for spec in specs if is_installed(spec)]
 
 
 def dependent_environments(
@@ -240,8 +239,6 @@ def get_uninstall_list(args, specs: List[spack.spec.Spec], env: Optional[ev.Envi
             print()
             tty.info("The following environments still reference these specs:")
             colify([e.name for e in other_dependent_envs.keys()], indent=4)
-            if env:
-                msgs.append("use `spack remove` to remove the spec from the current environment")
             msgs.append("use `spack env remove` to remove environments")
         msgs.append("use `spack uninstall --force` to override")
         print()

lib/spack/spack/cmd/view.py

@@ -38,10 +38,10 @@
 
 import spack.cmd
 import spack.environment as ev
+import spack.filesystem_view as fsv
 import spack.schema.projections
 import spack.store
 from spack.config import validate
-from spack.filesystem_view import YamlFilesystemView, view_func_parser
 from spack.util import spack_yaml as s_yaml
 
 description = "project packages to a compact naming scheme on the filesystem"
@@ -193,17 +193,13 @@ def view(parser, args):
         ordered_projections = {}
 
     # What method are we using for this view
-    if args.action in actions_link:
-        link_fn = view_func_parser(args.action)
-    else:
-        link_fn = view_func_parser("symlink")
-
-    view = YamlFilesystemView(
+    link_type = args.action if args.action in actions_link else "symlink"
+    view = fsv.YamlFilesystemView(
         path,
         spack.store.STORE.layout,
         projections=ordered_projections,
         ignore_conflicts=getattr(args, "ignore_conflicts", False),
-        link=link_fn,
+        link_type=link_type,
         verbose=args.verbose,
     )
 

lib/spack/spack/compiler.py

@@ -290,7 +290,7 @@ def __init__(
         operating_system,
         target,
         paths,
-        modules=None,
+        modules: Optional[List[str]] = None,
         alias=None,
         environment=None,
         extra_rpaths=None,

lib/spack/spack/compilers/__init__.py

@@ -156,15 +156,7 @@ def get_compiler_config_from_packages(
 def _compiler_config_from_package_config(config):
     compilers = []
     for entry in config:
-        try:
-            compiler = _compiler_config_from_external(entry)
-        except Exception as e:
-            msg = "Reading compiler from packages config section failed\n"
-            msg += f"  Compiler: {entry.get('spec', None)}\n"
-            msg += f"  Prefix: {entry.get('prefix', None)}\n"
-            msg += f"  Failure: {e}"
-            warnings.warn(msg)
-            compiler = None
+        compiler = _compiler_config_from_external(entry)
         if compiler:
             compilers.append(compiler)
 
@@ -228,10 +220,10 @@ def _compiler_config_from_external(config):
         operating_system = host_platform.operating_system("default_os")
         target = host_platform.target("default_target").microarchitecture
     else:
-        target = spec.target
+        target = spec.architecture.target
         if not target:
-            host_platform = spack.platforms.host()
-            target = host_platform.target("default_target").microarchitecture
+            target = spack.platforms.host().target("default_target")
+        target = target.microarchitecture
 
         operating_system = spec.os
         if not operating_system:

lib/spack/spack/compilers/clang.py

@@ -96,8 +96,6 @@ def verbose_flag(self):
 
     openmp_flag = "-fopenmp"
 
-    # C++ flags based on CMake Modules/Compiler/Clang.cmake
-
     @property
     def cxx11_flag(self):
         if self.real_version < Version("3.3"):
@@ -122,24 +120,6 @@ def cxx17_flag(self):
 
         return "-std=c++17"
 
-    @property
-    def cxx20_flag(self):
-        if self.real_version < Version("5.0"):
-            raise UnsupportedCompilerFlag(self, "the C++20 standard", "cxx20_flag", "< 5.0")
-        elif self.real_version < Version("11.0"):
-            return "-std=c++2a"
-        else:
-            return "-std=c++20"
-
-    @property
-    def cxx23_flag(self):
-        if self.real_version < Version("12.0"):
-            raise UnsupportedCompilerFlag(self, "the C++23 standard", "cxx23_flag", "< 12.0")
-        elif self.real_version < Version("17.0"):
-            return "-std=c++2b"
-        else:
-            return "-std=c++23"
-
     @property
     def c99_flag(self):
         return "-std=c99"
@@ -162,10 +142,7 @@ def c17_flag(self):
     def c23_flag(self):
         if self.real_version < Version("9.0"):
             raise UnsupportedCompilerFlag(self, "the C23 standard", "c23_flag", "< 9.0")
-        elif self.real_version < Version("18.0"):
-            return "-std=c2x"
-        else:
-            return "-std=c23"
+        return "-std=c2x"
 
     @property
     def cc_pic_flag(self):

lib/spack/spack/database.py

@@ -283,12 +283,9 @@ def __reduce__(self):
                 database.  If it is a spec, we'll evaluate
                 ``spec.satisfies(query_spec)``
 
-            known (bool or None): Specs that are "known" are those
-                for which Spack can locate a ``package.py`` file -- i.e.,
-                Spack "knows" how to install them.  Specs that are unknown may
-                represent packages that existed in a previous version of
-                Spack, but have since either changed their name or
-                been removed
+            predicate_fn: optional predicate taking an InstallRecord as argument, and returning
+                whether that record is selected for the query. It can be used to craft criteria
+                that need some data for selection not provided by the Database itself.
 
             installed (bool or InstallStatus or typing.Iterable or None):
                 if ``True``, includes only installed
@@ -588,6 +585,9 @@ def _path(self, spec: "spack.spec.Spec") -> pathlib.Path:
         return self.dir / f"{spec.name}-{spec.dag_hash()}"
 
 
+SelectType = Callable[[InstallRecord], bool]
+
+
 class Database:
     #: Fields written for each install record
     record_fields: Tuple[str, ...] = DEFAULT_INSTALL_RECORD_FIELDS
@@ -1367,7 +1367,7 @@ def _deprecate(self, spec, deprecator):
         self._data[spec_key] = spec_rec
 
     @_autospec
-    def mark(self, spec, key, value):
+    def mark(self, spec: "spack.spec.Spec", key: str, value: Any) -> None:
         """Mark an arbitrary record on a spec."""
         with self.write_transaction():
             return self._mark(spec, key, value)
@@ -1516,7 +1516,7 @@ def get_by_hash(self, dag_hash, default=None, installed=any):
     def _query(
         self,
         query_spec=any,
-        known=any,
+        predicate_fn: Optional[SelectType] = None,
         installed=True,
         explicit=any,
         start_date=None,
@@ -1524,7 +1524,7 @@ def _query(
         hashes=None,
         in_buildcache=any,
         origin=None,
-    ):
+    ) -> List["spack.spec.Spec"]:
         """Run a query on the database."""
 
         # TODO: Specs are a lot like queries.  Should there be a
@@ -1570,7 +1570,7 @@ def _query(
             if explicit is not any and rec.explicit != explicit:
                 continue
 
-            if known is not any and known(rec.spec.name):
+            if predicate_fn is not None and not predicate_fn(rec):
                 continue
 
             if start_date or end_date:
@@ -1655,14 +1655,14 @@ def query(self, *args, **kwargs):
         query.__doc__ = ""
     query.__doc__ += _QUERY_DOCSTRING
 
-    def query_one(self, query_spec, known=any, installed=True):
+    def query_one(self, query_spec, predicate_fn=None, installed=True):
         """Query for exactly one spec that matches the query spec.
 
         Raises an assertion error if more than one spec matches the
         query. Returns None if no installed package matches.
 
         """
-        concrete_specs = self.query(query_spec, known=known, installed=installed)
+        concrete_specs = self.query(query_spec, predicate_fn=predicate_fn, installed=installed)
         assert len(concrete_specs) <= 1
         return concrete_specs[0] if concrete_specs else None
 
@@ -1709,24 +1709,6 @@ def root(key, record):
                 if id(rec.spec) not in needed and rec.installed
             ]
 
-    def update_explicit(self, spec, explicit):
-        """
-        Update the spec's explicit state in the database.
-
-        Args:
-            spec (spack.spec.Spec): the spec whose install record is being updated
-            explicit (bool): ``True`` if the package was requested explicitly
-                by the user, ``False`` if it was pulled in as a dependency of
-                an explicit package.
-        """
-        rec = self.get_record(spec)
-        if explicit != rec.explicit:
-            with self.write_transaction():
-                message = "{s.name}@{s.version} : marking the package {0}"
-                status = "explicit" if explicit else "implicit"
-                tty.debug(message.format(status, s=spec))
-                rec.explicit = explicit
-
 
 class UpstreamDatabaseLockingError(SpackError):
     """Raised when an operation would need to lock an upstream database"""

lib/spack/spack/directives.py

@@ -97,7 +97,7 @@ class OpenMpi(Package):
 PatchesType = Optional[Union[Patcher, str, List[Union[Patcher, str]]]]
 
 
-SUPPORTED_LANGUAGES = ("fortran", "cxx")
+SUPPORTED_LANGUAGES = ("fortran", "cxx", "c")
 
 
 def _make_when_spec(value: WhenType) -> Optional["spack.spec.Spec"]:

lib/spack/spack/environment/depfile.py

@@ -9,11 +9,13 @@
 
 import os
 import re
+import shlex
 from enum import Enum
 from typing import List, Optional
 
 import spack.deptypes as dt
 import spack.environment.environment as ev
+import spack.paths
 import spack.spec
 import spack.traverse as traverse
 
@@ -226,6 +228,7 @@ def to_dict(self):
             "install_deps_target": self._target("install-deps"),
             "any_hash_target": self._target("%"),
             "jobserver_support": self.jobserver_support,
+            "spack_script": shlex.quote(spack.paths.spack_script),
             "adjacency_list": self.make_adjacency_list,
             "phony_convenience_targets": " ".join(self.phony_convenience_targets),
             "pkg_ids_variable": self.pkg_identifier_variable,

lib/spack/spack/environment/environment.py

@@ -30,6 +30,7 @@
 import spack.deptypes as dt
 import spack.error
 import spack.fetch_strategy
+import spack.filesystem_view as fsv
 import spack.hash_types as ht
 import spack.hooks
 import spack.main
@@ -52,7 +53,6 @@
 import spack.util.url
 import spack.version
 from spack import traverse
-from spack.filesystem_view import SimpleFilesystemView, inverse_view_func_parser, view_func_parser
 from spack.installer import PackageInstaller
 from spack.schema.env import TOP_LEVEL_KEY
 from spack.spec import Spec
@@ -606,7 +606,7 @@ def __init__(
         self.projections = projections
         self.select = select
         self.exclude = exclude
-        self.link_type = view_func_parser(link_type)
+        self.link_type = fsv.canonicalize_link_type(link_type)
         self.link = link
 
     def select_fn(self, spec):
@@ -640,7 +640,7 @@ def to_dict(self):
         if self.exclude:
             ret["exclude"] = self.exclude
         if self.link_type:
-            ret["link_type"] = inverse_view_func_parser(self.link_type)
+            ret["link_type"] = self.link_type
         if self.link != default_view_link:
             ret["link"] = self.link
         return ret
@@ -690,7 +690,7 @@ def get_projection_for_spec(self, spec):
         to exist on the filesystem."""
         return self._view(self.root).get_projection_for_spec(spec)
 
-    def view(self, new: Optional[str] = None) -> SimpleFilesystemView:
+    def view(self, new: Optional[str] = None) -> fsv.SimpleFilesystemView:
         """
         Returns a view object for the *underlying* view directory. This means that the
         self.root symlink is followed, and that the view has to exist on the filesystem
@@ -710,14 +710,14 @@ def view(self, new: Optional[str] = None) -> SimpleFilesystemView:
             )
         return self._view(path)
 
-    def _view(self, root: str) -> SimpleFilesystemView:
+    def _view(self, root: str) -> fsv.SimpleFilesystemView:
         """Returns a view object for a given root dir."""
-        return SimpleFilesystemView(
+        return fsv.SimpleFilesystemView(
             root,
             spack.store.STORE.layout,
             ignore_conflicts=True,
             projections=self.projections,
-            link=self.link_type,
+            link_type=self.link_type,
         )
 
     def __contains__(self, spec):
@@ -1190,7 +1190,6 @@ 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 = {}
@@ -1201,37 +1200,26 @@ def include_concrete_envs(self):
                 raise SpackEnvironmentError(f"Unable to find env at {env_path}")
 
             env = Environment(env_path)
-
-            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")
+            self.included_concrete_spec_data[env_path] = {"roots": [], "concrete_specs": {}}
 
             # Copy unique root specs from env
-            self.included_concrete_spec_data[env_path] = {"roots": []}
-            for root_dict in lockfile_as_dict["roots"]:
+            for root_dict in env._concrete_roots_dict():
                 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 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"]}
+            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}
                     )
-                    concrete_hash_seen.add(concrete_spec)
+                    concrete_hash_seen.add(dag_hash)
 
-            if "include_concrete" in lockfile_as_dict.keys():
-                self.included_concrete_spec_data[env_path]["include_concrete"] = lockfile_as_dict[
-                    "include_concrete"
-                ]
+            # Copy transitive include data
+            transitive = env.included_concrete_spec_data
+            if transitive:
+                self.included_concrete_spec_data[env_path]["include_concrete"] = transitive
 
         self._read_lockfile_dict(self._to_lockfile_dict())
         self.write()
@@ -1948,13 +1936,18 @@ def install_specs(self, specs: Optional[List[Spec]] = None, **install_args):
         specs = specs if specs is not None else roots
 
         # Extend the set of specs to overwrite with modified dev specs and their parents
-        install_args["overwrite"] = (
-            install_args.get("overwrite", []) + self._dev_specs_that_need_overwrite()
-        )
+        install_args["overwrite"] = {
+            *install_args.get("overwrite", ()),
+            *self._dev_specs_that_need_overwrite(),
+        }
 
-        installs = [(spec.package, {**install_args, "explicit": spec in roots}) for spec in specs]
+        # Only environment roots are marked explicit
+        install_args["explicit"] = {
+            *install_args.get("explicit", ()),
+            *(s.dag_hash() for s in roots),
+        }
 
-        PackageInstaller(installs).install()
+        PackageInstaller([spec.package for spec in specs], install_args).install()
 
     def all_specs_generator(self) -> Iterable[Spec]:
         """Returns a generator for all concrete specs"""
@@ -2144,16 +2137,23 @@ def _get_environment_specs(self, recurse_dependencies=True):
 
         return specs
 
-    def _to_lockfile_dict(self):
-        """Create a dictionary to store a lockfile for this environment."""
+    def _concrete_specs_dict(self):
         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()
@@ -2174,7 +2174,7 @@ def _to_lockfile_dict(self):
             # spack version information
             "spack": spack_dict,
             # users specs + hashes are the 'roots' of the environment
-            "roots": [{"hash": h, "spec": str(s)} for h, s in hash_spec_list],
+            "roots": root_specs,
             # Concrete specs by hash, including dependencies
             "concrete_specs": concrete_specs,
         }

lib/spack/spack/fetch_strategy.py

@@ -30,6 +30,7 @@
 import shutil
 import urllib.error
 import urllib.parse
+import urllib.request
 from pathlib import PurePath
 from typing import List, Optional
 
@@ -273,10 +274,7 @@ def __init__(self, url=None, checksum=None, **kwargs):
     @property
     def curl(self):
         if not self._curl:
-            try:
-                self._curl = which("curl", required=True)
-            except CommandNotFoundError as exc:
-                tty.error(str(exc))
+            self._curl = web_util.require_curl()
         return self._curl
 
     def source_id(self):
@@ -297,27 +295,23 @@ def candidate_urls(self):
     @_needs_stage
     def fetch(self):
         if self.archive_file:
-            tty.debug("Already downloaded {0}".format(self.archive_file))
+            tty.debug(f"Already downloaded {self.archive_file}")
             return
 
-        url = None
-        errors = []
+        errors: List[Exception] = []
         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.append(str(e))
-
-        for msg in errors:
-            tty.debug(msg)
+                errors.extend(e.exceptions)
+        else:
+            raise FailedDownloadError(*errors)
 
         if not self.archive_file:
-            raise FailedDownloadError(url)
+            raise FailedDownloadError(
+                RuntimeError(f"Missing archive {self.archive_file} after fetching")
+            )
 
     def _fetch_from_url(self, url):
         if spack.config.get("config:url_fetch_method") == "curl":
@@ -336,19 +330,20 @@ def _check_headers(self, headers):
     @_needs_stage
     def _fetch_urllib(self, url):
         save_file = self.stage.save_filename
-        tty.msg("Fetching {0}".format(url))
 
-        # Run urllib but grab the mime type from the http headers
+        request = urllib.request.Request(url, headers={"User-Agent": web_util.SPACK_USER_AGENT})
+
         try:
-            url, headers, response = web_util.read_from_url(url)
-        except web_util.SpackWebError as e:
+            response = web_util.urlopen(request)
+        except (TimeoutError, urllib.error.URLError) 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)
-            msg = "urllib failed to fetch with error {0}".format(e)
-            raise FailedDownloadError(url, msg)
+            raise FailedDownloadError(e) from e
+
+        tty.msg(f"Fetching {url}")
 
         if os.path.lexists(save_file):
             os.remove(save_file)
@@ -356,7 +351,7 @@ def _fetch_urllib(self, url):
         with open(save_file, "wb") as _open_file:
             shutil.copyfileobj(response, _open_file)
 
-        self._check_headers(str(headers))
+        self._check_headers(str(response.headers))
 
     @_needs_stage
     def _fetch_curl(self, url):
@@ -365,7 +360,7 @@ 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("Fetching {0}".format(url))
+        tty.msg(f"Fetching {url}")
         if partial_file:
             save_args = [
                 "-C",
@@ -405,8 +400,8 @@ def _fetch_curl(self, url):
 
             try:
                 web_util.check_curl_code(curl.returncode)
-            except spack.error.FetchError as err:
-                raise spack.fetch_strategy.FailedDownloadError(url, str(err))
+            except spack.error.FetchError as e:
+                raise FailedDownloadError(e) from e
 
         self._check_headers(headers)
 
@@ -554,13 +549,13 @@ def fetch(self):
 
         try:
             response = self._urlopen(self.url)
-        except urllib.error.URLError as e:
+        except (TimeoutError, 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(self.url, f"Failed to fetch {self.url}: {e}") from e
+            raise FailedDownloadError(e) from e
 
         if os.path.lexists(file):
             os.remove(file)
@@ -1312,35 +1307,41 @@ def __init__(self, *args, **kwargs):
     @_needs_stage
     def fetch(self):
         if self.archive_file:
-            tty.debug("Already downloaded {0}".format(self.archive_file))
+            tty.debug(f"Already downloaded {self.archive_file}")
             return
 
         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)
+        request = urllib.request.Request(
+            self.url, headers={"User-Agent": web_util.SPACK_USER_AGENT}
+        )
 
         with working_dir(self.stage.path):
-            _, headers, stream = web_util.read_from_url(self.url)
+            try:
+                response = web_util.urlopen(request)
+            except (TimeoutError, urllib.error.URLError) as e:
+                raise FailedDownloadError(e) from e
+
+            tty.debug(f"Fetching {self.url}")
 
             with open(basename, "wb") as f:
-                shutil.copyfileobj(stream, f)
+                shutil.copyfileobj(response, f)
 
-            content_type = web_util.get_header(headers, "Content-type")
+            content_type = web_util.get_header(response.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
-            )
+            fs.rename(os.path.join(self.stage.path, basename), self.stage.save_filename)
 
         if not self.archive_file:
-            raise FailedDownloadError(self.url)
+            raise FailedDownloadError(
+                RuntimeError(f"Missing archive {self.archive_file} after fetching")
+            )
 
 
 @fetcher
@@ -1366,17 +1367,23 @@ def fetch(self):
         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)
+        request = urllib.request.Request(
+            self.url, headers={"User-Agent": web_util.SPACK_USER_AGENT}
+        )
 
         with working_dir(self.stage.path):
-            _, headers, stream = web_util.read_from_url(self.url)
+            try:
+                response = web_util.urlopen(request)
+            except (TimeoutError, urllib.error.URLError) as e:
+                raise FailedDownloadError(e) from e
+
+            tty.debug(f"Fetching {self.url}")
 
             with open(basename, "wb") as f:
-                shutil.copyfileobj(stream, f)
+                shutil.copyfileobj(response, f)
 
-            content_type = web_util.get_header(headers, "Content-type")
+            content_type = web_util.get_header(response.headers, "Content-type")
 
         if content_type == "text/html":
             warn_content_type_mismatch(self.archive_file or "the archive")
@@ -1385,7 +1392,9 @@ def fetch(self):
             os.rename(os.path.join(self.stage.path, basename), self.stage.save_filename)
 
         if not self.archive_file:
-            raise FailedDownloadError(self.url)
+            raise FailedDownloadError(
+                RuntimeError(f"Missing archive {self.archive_file} after fetching")
+            )
 
 
 @fetcher
@@ -1722,9 +1731,9 @@ class NoCacheError(spack.error.FetchError):
 class FailedDownloadError(spack.error.FetchError):
     """Raised when a download fails."""
 
-    def __init__(self, url, msg=""):
-        super().__init__("Failed to fetch file from URL: %s" % url, msg)
-        self.url = url
+    def __init__(self, *exceptions: Exception):
+        super().__init__("Failed to download")
+        self.exceptions = exceptions
 
 
 class NoArchiveFileError(spack.error.FetchError):

lib/spack/spack/filesystem_view.py

@@ -10,8 +10,9 @@
 import shutil
 import stat
 import sys
-from typing import Optional
+from typing import Callable, Dict, Optional
 
+from llnl.string import comma_or
 from llnl.util import tty
 from llnl.util.filesystem import (
     mkdirp,
@@ -32,6 +33,7 @@
 from llnl.util.tty.color import colorize
 
 import spack.config
+import spack.directory_layout
 import spack.paths
 import spack.projections
 import spack.relocate
@@ -49,19 +51,20 @@
 _projections_path = ".spack/projections.yaml"
 
 
-def view_symlink(src, dst, **kwargs):
-    # keyword arguments are irrelevant
-    # here to fit required call signature
+LinkCallbackType = Callable[[str, str, "FilesystemView", Optional[spack.spec.Spec]], None]
+
+
+def view_symlink(src: str, dst: str, *args, **kwargs) -> None:
     symlink(src, dst)
 
 
-def view_hardlink(src, dst, **kwargs):
-    # keyword arguments are irrelevant
-    # here to fit required call signature
+def view_hardlink(src: str, dst: str, *args, **kwargs) -> None:
     os.link(src, dst)
 
 
-def view_copy(src: str, dst: str, view, spec: Optional[spack.spec.Spec] = None):
+def view_copy(
+    src: str, dst: str, view: "FilesystemView", spec: Optional[spack.spec.Spec] = None
+) -> None:
     """
     Copy a file from src to dst.
 
@@ -104,27 +107,40 @@ def view_copy(src: str, dst: str, view, spec: Optional[spack.spec.Spec] = None):
         tty.debug(f"Can't change the permissions for {dst}")
 
 
-def view_func_parser(parsed_name):
-    # What method are we using for this view
-    if parsed_name in ("hardlink", "hard"):
+#: supported string values for `link_type` in an env, mapped to canonical values
+_LINK_TYPES = {
+    "hardlink": "hardlink",
+    "hard": "hardlink",
+    "copy": "copy",
+    "relocate": "copy",
+    "add": "symlink",
+    "symlink": "symlink",
+    "soft": "symlink",
+}
+
+_VALID_LINK_TYPES = sorted(set(_LINK_TYPES.values()))
+
+
+def canonicalize_link_type(link_type: str) -> str:
+    """Return canonical"""
+    canonical = _LINK_TYPES.get(link_type)
+    if not canonical:
+        raise ValueError(
+            f"Invalid link type: '{link_type}. Must be one of {comma_or(_VALID_LINK_TYPES)}'"
+        )
+    return canonical
+
+
+def function_for_link_type(link_type: str) -> LinkCallbackType:
+    link_type = canonicalize_link_type(link_type)
+    if link_type == "hardlink":
         return view_hardlink
-    elif parsed_name in ("copy", "relocate"):
-        return view_copy
-    elif parsed_name in ("add", "symlink", "soft"):
+    elif link_type == "symlink":
         return view_symlink
-    else:
-        raise ValueError(f"invalid link type for view: '{parsed_name}'")
+    elif link_type == "copy":
+        return view_copy
 
-
-def inverse_view_func_parser(view_type):
-    # get string based on view type
-    if view_type is view_hardlink:
-        link_name = "hardlink"
-    elif view_type is view_copy:
-        link_name = "copy"
-    else:
-        link_name = "symlink"
-    return link_name
+    assert False, "invalid link type"  # need mypy Literal values
 
 
 class FilesystemView:
@@ -140,7 +156,16 @@ class FilesystemView:
     directory structure.
     """
 
-    def __init__(self, root, layout, **kwargs):
+    def __init__(
+        self,
+        root: str,
+        layout: spack.directory_layout.DirectoryLayout,
+        *,
+        projections: Optional[Dict] = None,
+        ignore_conflicts: bool = False,
+        verbose: bool = False,
+        link_type: str = "symlink",
+    ):
         """
         Initialize a filesystem view under the given `root` directory with
         corresponding directory `layout`.
@@ -149,15 +174,17 @@ def __init__(self, root, layout, **kwargs):
         """
         self._root = root
         self.layout = layout
+        self.projections = {} if projections is None else projections
 
-        self.projections = kwargs.get("projections", {})
-
-        self.ignore_conflicts = kwargs.get("ignore_conflicts", False)
-        self.verbose = kwargs.get("verbose", False)
+        self.ignore_conflicts = ignore_conflicts
+        self.verbose = verbose
 
         # Setup link function to include view
-        link_func = kwargs.get("link", view_symlink)
-        self.link = ft.partial(link_func, view=self)
+        self.link_type = link_type
+        self._link = function_for_link_type(link_type)
+
+    def link(self, src: str, dst: str, spec: Optional[spack.spec.Spec] = None) -> None:
+        self._link(src, dst, self, spec)
 
     def add_specs(self, *specs, **kwargs):
         """
@@ -255,8 +282,24 @@ class YamlFilesystemView(FilesystemView):
     Filesystem view to work with a yaml based directory layout.
     """
 
-    def __init__(self, root, layout, **kwargs):
-        super().__init__(root, layout, **kwargs)
+    def __init__(
+        self,
+        root: str,
+        layout: spack.directory_layout.DirectoryLayout,
+        *,
+        projections: Optional[Dict] = None,
+        ignore_conflicts: bool = False,
+        verbose: bool = False,
+        link_type: str = "symlink",
+    ):
+        super().__init__(
+            root,
+            layout,
+            projections=projections,
+            ignore_conflicts=ignore_conflicts,
+            verbose=verbose,
+            link_type=link_type,
+        )
 
         # Super class gets projections from the kwargs
         # YAML specific to get projections from YAML file
@@ -638,9 +681,6 @@ class SimpleFilesystemView(FilesystemView):
     """A simple and partial implementation of FilesystemView focused on performance and immutable
     views, where specs cannot be removed after they were added."""
 
-    def __init__(self, root, layout, **kwargs):
-        super().__init__(root, layout, **kwargs)
-
     def _sanity_check_view_projection(self, specs):
         """A very common issue is that we end up with two specs of the same package, that project
         to the same prefix. We want to catch that as early as possible and give a sensible error to

lib/spack/spack/hooks/__init__.py

@@ -41,8 +41,9 @@ def _populate_hooks(cls):
 
         relative_names = list(list_modules(spack.paths.hooks_path))
 
-        # Ensure that write_install_manifest comes last
-        ensure_last(relative_names, "absolutify_elf_sonames", "write_install_manifest")
+        # write_install_manifest should come after any mutation of the install prefix, and
+        # autopush should include the install manifest.
+        ensure_last(relative_names, "absolutify_elf_sonames", "write_install_manifest", "autopush")
 
         for name in relative_names:
             module_name = __name__ + "." + name

lib/spack/spack/installer.py

@@ -440,7 +440,7 @@ def _process_external_package(pkg: "spack.package_base.PackageBase", explicit: b
         tty.debug(f"{pre} already registered in DB")
         record = spack.store.STORE.db.get_record(spec)
         if explicit and not record.explicit:
-            spack.store.STORE.db.update_explicit(spec, explicit)
+            spack.store.STORE.db.mark(spec, "explicit", True)
 
     except KeyError:
         # If not, register it and generate the module file.
@@ -761,12 +761,8 @@ def __init__(self, pkg: "spack.package_base.PackageBase", install_args: dict):
         if not self.pkg.spec.concrete:
             raise ValueError(f"{self.pkg.name} must have a concrete spec")
 
-        # Cache the package phase options with the explicit package,
-        # popping the options to ensure installation of associated
-        # dependencies is NOT affected by these options.
-
-        self.pkg.stop_before_phase = install_args.pop("stop_before", None)  # type: ignore[attr-defined] # noqa: E501
-        self.pkg.last_phase = install_args.pop("stop_at", None)  # type: ignore[attr-defined]
+        self.pkg.stop_before_phase = install_args.get("stop_before")  # type: ignore[attr-defined] # noqa: E501
+        self.pkg.last_phase = install_args.get("stop_at")  # type: ignore[attr-defined]
 
         # Cache the package id for convenience
         self.pkg_id = package_id(pkg.spec)
@@ -1076,19 +1072,17 @@ def flag_installed(self, installed: List[str]) -> None:
 
     @property
     def explicit(self) -> bool:
-        """The package was explicitly requested by the user."""
-        return self.is_root and self.request.install_args.get("explicit", True)
+        return self.pkg.spec.dag_hash() in self.request.install_args.get("explicit", [])
 
     @property
-    def is_root(self) -> bool:
-        """The package was requested directly, but may or may not be explicit
-        in an environment."""
+    def is_build_request(self) -> bool:
+        """The package was requested directly"""
         return self.pkg == self.request.pkg
 
     @property
     def use_cache(self) -> bool:
         _use_cache = True
-        if self.is_root:
+        if self.is_build_request:
             return self.request.install_args.get("package_use_cache", _use_cache)
         else:
             return self.request.install_args.get("dependencies_use_cache", _use_cache)
@@ -1096,7 +1090,7 @@ def use_cache(self) -> bool:
     @property
     def cache_only(self) -> bool:
         _cache_only = False
-        if self.is_root:
+        if self.is_build_request:
             return self.request.install_args.get("package_cache_only", _cache_only)
         else:
             return self.request.install_args.get("dependencies_cache_only", _cache_only)
@@ -1122,24 +1116,17 @@ def priority(self):
 
 class PackageInstaller:
     """
-    Class for managing the install process for a Spack instance based on a
-    bottom-up DAG approach.
+    Class for managing the install process for a Spack instance based on a bottom-up DAG approach.
 
-    This installer can coordinate concurrent batch and interactive, local
-    and distributed (on a shared file system) builds for the same Spack
-    instance.
+    This installer can coordinate concurrent batch and interactive, local and distributed (on a
+    shared file system) builds for the same Spack instance.
     """
 
-    def __init__(self, installs: List[Tuple["spack.package_base.PackageBase", dict]] = []) -> None:
-        """Initialize the installer.
-
-        Args:
-            installs (list): list of tuples, where each
-                tuple consists of a package (PackageBase) and its associated
-                 install arguments (dict)
-        """
+    def __init__(
+        self, packages: List["spack.package_base.PackageBase"], install_args: dict
+    ) -> None:
         # List of build requests
-        self.build_requests = [BuildRequest(pkg, install_args) for pkg, install_args in installs]
+        self.build_requests = [BuildRequest(pkg, install_args) for pkg in packages]
 
         # Priority queue of build tasks
         self.build_pq: List[Tuple[Tuple[int, int], BuildTask]] = []
@@ -1376,8 +1363,8 @@ def _prepare_for_install(self, task: BuildTask) -> None:
             self._update_installed(task)
 
             # Only update the explicit entry once for the explicit package
-            if task.explicit:
-                spack.store.STORE.db.update_explicit(task.pkg.spec, True)
+            if task.explicit and not rec.explicit:
+                spack.store.STORE.db.mark(task.pkg.spec, "explicit", True)
 
     def _cleanup_all_tasks(self) -> None:
         """Cleanup all build tasks to include releasing their locks."""
@@ -1557,17 +1544,6 @@ def _add_tasks(self, request: BuildRequest, all_deps):
             tty.warn(f"Installation request refused: {str(err)}")
             return
 
-        # Skip out early if the spec is not being installed locally (i.e., if
-        # external or upstream).
-        #
-        # External and upstream packages need to get flagged as installed to
-        # ensure proper status tracking for environment build.
-        explicit = request.install_args.get("explicit", True)
-        not_local = _handle_external_and_upstream(request.pkg, explicit)
-        if not_local:
-            self._flag_installed(request.pkg)
-            return
-
         install_compilers = spack.config.get("config:install_missing_compilers", False)
 
         install_deps = request.install_args.get("install_deps")
@@ -1683,10 +1659,6 @@ def _install_task(self, task: BuildTask, install_status: InstallStatus) -> None:
         if not pkg.unit_test_check():
             return
 
-        # Injecting information to know if this installation request is the root one
-        # to determine in BuildProcessInstaller whether installation is explicit or not
-        install_args["is_root"] = task.is_root
-
         try:
             self._setup_install_dir(pkg)
 
@@ -1998,8 +1970,8 @@ def install(self) -> None:
 
         self._init_queue()
         fail_fast_err = "Terminating after first install failure"
-        single_explicit_spec = len(self.build_requests) == 1
-        failed_explicits = []
+        single_requested_spec = len(self.build_requests) == 1
+        failed_build_requests = []
 
         install_status = InstallStatus(len(self.build_pq))
 
@@ -2048,11 +2020,10 @@ def install(self) -> None:
             # Skip the installation if the spec is not being installed locally
             # (i.e., if external or upstream) BUT flag it as installed since
             # some package likely depends on it.
-            if not task.explicit:
-                if _handle_external_and_upstream(pkg, False):
-                    term_status.clear()
-                    self._flag_installed(pkg, task.dependents)
-                    continue
+            if _handle_external_and_upstream(pkg, task.explicit):
+                term_status.clear()
+                self._flag_installed(pkg, task.dependents)
+                continue
 
             # Flag a failed spec.  Do not need an (install) prefix lock since
             # assume using a separate (failed) prefix lock file.
@@ -2197,14 +2168,11 @@ def install(self) -> None:
                 if self.fail_fast:
                     raise InstallError(f"{fail_fast_err}: {str(exc)}", pkg=pkg)
 
-                # Terminate at this point if the single explicit spec has
-                # failed to install.
-                if single_explicit_spec and task.explicit:
-                    raise
-
-                # Track explicit spec id and error to summarize when done
-                if task.explicit:
-                    failed_explicits.append((pkg, pkg_id, str(exc)))
+                # Terminate when a single build request has failed, or summarize errors later.
+                if task.is_build_request:
+                    if single_requested_spec:
+                        raise
+                    failed_build_requests.append((pkg, pkg_id, str(exc)))
 
             finally:
                 # Remove the install prefix if anything went wrong during
@@ -2227,16 +2195,16 @@ def install(self) -> None:
             if request.install_args.get("install_package") and request.pkg_id not in self.installed
         ]
 
-        if failed_explicits or missing:
-            for _, pkg_id, err in failed_explicits:
+        if failed_build_requests or missing:
+            for _, pkg_id, err in failed_build_requests:
                 tty.error(f"{pkg_id}: {err}")
 
             for _, pkg_id in missing:
                 tty.error(f"{pkg_id}: Package was not installed")
 
-            if len(failed_explicits) > 0:
-                pkg = failed_explicits[0][0]
-                ids = [pkg_id for _, pkg_id, _ in failed_explicits]
+            if len(failed_build_requests) > 0:
+                pkg = failed_build_requests[0][0]
+                ids = [pkg_id for _, pkg_id, _ in failed_build_requests]
                 tty.debug(
                     "Associating installation failure with first failed "
                     f"explicit package ({ids[0]}) from {', '.join(ids)}"
@@ -2295,7 +2263,7 @@ def __init__(self, pkg: "spack.package_base.PackageBase", install_args: dict):
         self.verbose = bool(install_args.get("verbose", False))
 
         # whether installation was explicitly requested by the user
-        self.explicit = install_args.get("is_root", False) and install_args.get("explicit", True)
+        self.explicit = pkg.spec.dag_hash() in install_args.get("explicit", [])
 
         # env before starting installation
         self.unmodified_env = install_args.get("unmodified_env", {})

lib/spack/spack/mirror.py

@@ -87,9 +87,8 @@ def from_url(url: str):
         """Create an anonymous mirror by URL. This method validates the URL."""
         if not urllib.parse.urlparse(url).scheme in supported_url_schemes:
             raise ValueError(
-                '"{}" is not a valid mirror URL. Scheme must be once of {}.'.format(
-                    url, ", ".join(supported_url_schemes)
-                )
+                f'"{url}" is not a valid mirror URL. '
+                f"Scheme must be one of {supported_url_schemes}."
             )
         return Mirror(url)
 
@@ -734,7 +733,7 @@ def require_mirror_name(mirror_name):
     """Find a mirror by name and raise if it does not exist"""
     mirror = spack.mirror.MirrorCollection().get(mirror_name)
     if not mirror:
-        raise ValueError('no mirror named "{0}"'.format(mirror_name))
+        raise ValueError(f'no mirror named "{mirror_name}"')
     return mirror
 
 

lib/spack/spack/operating_systems/mac_os.py

@@ -143,6 +143,7 @@ def __init__(self):
             "12": "monterey",
             "13": "ventura",
             "14": "sonoma",
+            "15": "sequoia",
         }
 
         version = macos_version()

lib/spack/spack/package_base.py

@@ -199,10 +199,10 @@ def __init__(cls, name, bases, attr_dict):
         # assumed to be detectable
         if hasattr(cls, "executables") or hasattr(cls, "libraries"):
             # Append a tag to each detectable package, so that finding them is faster
-            if hasattr(cls, "tags"):
-                getattr(cls, "tags").append(DetectablePackageMeta.TAG)
-            else:
+            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):
@@ -1119,10 +1119,9 @@ def _make_stage(self):
             if not link_format:
                 link_format = "build-{arch}-{hash:7}"
             stage_link = self.spec.format_path(link_format)
-            return DevelopStage(compute_stage_name(self.spec), dev_path, stage_link)
-
-        # To fetch the current version
-        source_stage = self._make_root_stage(self.fetcher)
+            source_stage = DevelopStage(compute_stage_name(self.spec), dev_path, stage_link)
+        else:
+            source_stage = self._make_root_stage(self.fetcher)
 
         # all_stages is source + resources + patches
         all_stages = StageComposite()
@@ -1451,10 +1450,8 @@ def do_fetch(self, mirror_only=False):
             return
 
         checksum = spack.config.get("config:checksum")
-        fetch = self.stage.needs_fetching
         if (
             checksum
-            and fetch
             and (self.version not in self.versions)
             and (not isinstance(self.version, GitVersion))
         ):
@@ -1561,13 +1558,11 @@ def do_patch(self):
                 tty.debug("Patching failed last time. Restaging.")
                 self.stage.restage()
             else:
-                # develop specs/ DIYStages may have patch failures but
-                # should never be restaged
-                msg = (
-                    "A patch failure was detected in %s." % self.name
-                    + " Build errors may occur due to this."
+                # develop specs may have patch failures but should never be restaged
+                tty.warn(
+                    f"A patch failure was detected in {self.name}."
+                    " Build errors may occur due to this."
                 )
-                tty.warn(msg)
                 return
 
         # If this file exists, then we already applied all the patches.
@@ -1881,7 +1876,10 @@ def do_install(self, **kwargs):
             verbose (bool): Display verbose build output (by default,
                 suppresses it)
         """
-        PackageInstaller([(self, kwargs)]).install()
+        explicit = kwargs.get("explicit", True)
+        if isinstance(explicit, bool):
+            kwargs["explicit"] = {self.spec.dag_hash()} if explicit else set()
+        PackageInstaller([self], kwargs).install()
 
     # TODO (post-34236): Update tests and all packages that use this as a
     # TODO (post-34236): package method to the routine made available to

lib/spack/spack/schema/compilers.py

@@ -52,7 +52,10 @@
                         "target": {"type": "string"},
                         "alias": {"anyOf": [{"type": "string"}, {"type": "null"}]},
                         "modules": {
-                            "anyOf": [{"type": "string"}, {"type": "null"}, {"type": "array"}]
+                            "anyOf": [
+                                {"type": "null"},
+                                {"type": "array", "items": {"type": "string"}},
+                            ]
                         },
                         "implicit_rpaths": {
                             "anyOf": [

lib/spack/spack/schema/develop.py

@@ -13,6 +13,7 @@
             r"\w[\w-]*": {
                 "type": "object",
                 "additionalProperties": False,
+                "required": ["spec"],
                 "properties": {"spec": {"type": "string"}, "path": {"type": "string"}},
             }
         },

lib/spack/spack/solver/asp.py

@@ -844,8 +844,6 @@ def solve(self, setup, specs, reuse=None, output=None, control=None, allow_depre
         parent_dir = os.path.dirname(__file__)
         self.control.load(os.path.join(parent_dir, "concretize.lp"))
         self.control.load(os.path.join(parent_dir, "heuristic.lp"))
-        if spack.config.CONFIG.get("concretizer:duplicates:strategy", "none") != "none":
-            self.control.load(os.path.join(parent_dir, "heuristic_separate.lp"))
         self.control.load(os.path.join(parent_dir, "display.lp"))
         if not setup.concretize_everything:
             self.control.load(os.path.join(parent_dir, "when_possible.lp"))
@@ -1435,16 +1433,14 @@ def condition(
             # caller, we won't emit partial facts.
 
             condition_id = next(self._id_counter)
-            self.gen.fact(fn.pkg_fact(required_spec.name, fn.condition(condition_id)))
-            self.gen.fact(fn.condition_reason(condition_id, msg))
-
             trigger_id = self._get_condition_id(
                 required_spec, cache=self._trigger_cache, body=True, transform=transform_required
             )
+            self.gen.fact(fn.pkg_fact(required_spec.name, fn.condition(condition_id)))
+            self.gen.fact(fn.condition_reason(condition_id, msg))
             self.gen.fact(
                 fn.pkg_fact(required_spec.name, fn.condition_trigger(condition_id, trigger_id))
             )
-
             if not imposed_spec:
                 return condition_id
 
@@ -1693,19 +1689,43 @@ def external_packages(self):
                 spack.spec.parse_with_version_concrete(x["spec"]) for x in externals
             ]
 
-            external_specs = []
+            selected_externals = set()
             if spec_filters:
                 for current_filter in spec_filters:
                     current_filter.factory = lambda: candidate_specs
-                    external_specs.extend(current_filter.selected_specs())
-            else:
-                external_specs.extend(candidate_specs)
+                    selected_externals.update(current_filter.selected_specs())
+
+            # Emit facts for externals specs. Note that "local_idx" is the index of the spec
+            # in packages:<pkg_name>:externals. This means:
+            #
+            # packages:<pkg_name>:externals[local_idx].spec == spec
+            external_versions = []
+            for local_idx, spec in enumerate(candidate_specs):
+                msg = f"{spec.name} available as external when satisfying {spec}"
+
+                if spec_filters and spec not in selected_externals:
+                    continue
+
+                if not spec.versions.concrete:
+                    warnings.warn(f"cannot use the external spec {spec}: needs a concrete version")
+                    continue
+
+                def external_imposition(input_spec, requirements):
+                    return requirements + [
+                        fn.attr("external_conditions_hold", input_spec.name, local_idx)
+                    ]
+
+                try:
+                    self.condition(spec, spec, msg=msg, transform_imposed=external_imposition)
+                except (spack.error.SpecError, RuntimeError) as e:
+                    warnings.warn(f"while setting up external spec {spec}: {e}")
+                    continue
+                external_versions.append((spec.version, local_idx))
+                self.possible_versions[spec.name].add(spec.version)
+                self.gen.newline()
 
             # Order the external versions to prefer more recent versions
             # even if specs in packages.yaml are not ordered that way
-            external_versions = [
-                (x.version, external_id) for external_id, x in enumerate(external_specs)
-            ]
             external_versions = [
                 (v, idx, external_id)
                 for idx, (v, external_id) in enumerate(sorted(external_versions, reverse=True))
@@ -1715,19 +1735,6 @@ def external_packages(self):
                     DeclaredVersion(version=version, idx=idx, origin=Provenance.EXTERNAL)
                 )
 
-            # Declare external conditions with a local index into packages.yaml
-            for local_idx, spec in enumerate(external_specs):
-                msg = "%s available as external when satisfying %s" % (spec.name, spec)
-
-                def external_imposition(input_spec, requirements):
-                    return requirements + [
-                        fn.attr("external_conditions_hold", input_spec.name, local_idx)
-                    ]
-
-                self.condition(spec, spec, msg=msg, transform_imposed=external_imposition)
-                self.possible_versions[spec.name].add(spec.version)
-                self.gen.newline()
-
             self.trigger_rules()
             self.effect_rules()
 
@@ -1880,11 +1887,8 @@ def _spec_clauses(
                             )
 
                 clauses.append(f.variant_value(spec.name, vname, value))
-
                 if variant.propagate:
-                    clauses.append(
-                        f.variant_propagation_candidate(spec.name, vname, value, spec.name)
-                    )
+                    clauses.append(f.propagate(spec.name, fn.variant_value(vname, value)))
 
                 # Tell the concretizer that this is a possible value for the
                 # variant, to account for things like int/str values where we
@@ -1939,6 +1943,11 @@ def _spec_clauses(
             for virtual in virtuals:
                 clauses.append(fn.attr("virtual_on_incoming_edges", spec.name, virtual))
 
+        # If the spec is external and concrete, we allow all the libcs on the system
+        if spec.external and spec.concrete and using_libc_compatibility():
+            for libc in self.libcs:
+                clauses.append(fn.attr("compatible_libc", spec.name, libc.name, libc.version))
+
         # add all clauses from dependencies
         if transitive:
             # TODO: Eventually distinguish 2 deps on the same pkg (build and link)
@@ -2734,7 +2743,7 @@ class _Head:
     node_flag = fn.attr("node_flag_set")
     node_flag_source = fn.attr("node_flag_source")
     node_flag_propagate = fn.attr("node_flag_propagate")
-    variant_propagation_candidate = fn.attr("variant_propagation_candidate")
+    propagate = fn.attr("propagate")
 
 
 class _Body:
@@ -2751,7 +2760,7 @@ class _Body:
     node_flag = fn.attr("node_flag")
     node_flag_source = fn.attr("node_flag_source")
     node_flag_propagate = fn.attr("node_flag_propagate")
-    variant_propagation_candidate = fn.attr("variant_propagation_candidate")
+    propagate = fn.attr("propagate")
 
 
 class ProblemInstanceBuilder:
@@ -3225,6 +3234,39 @@ def requires(self, impose: str, *, when: str):
         self.runtime_conditions.add((imposed_spec, when_spec))
         self.reset()
 
+    def propagate(self, constraint_str: str, *, when: str):
+        msg = "the 'propagate' method can be called only with pkg('*')"
+        assert self.current_package == "*", msg
+
+        when_spec = spack.spec.Spec(when)
+        assert when_spec.name is None, "only anonymous when specs are accepted"
+
+        placeholder = "XXX"
+        node_variable = "node(ID, Package)"
+        when_spec.name = placeholder
+
+        body_clauses = self._setup.spec_clauses(when_spec, body=True)
+        body_str = (
+            f"  {f',{os.linesep}  '.join(str(x) for x in body_clauses)},\n"
+            f"  not external({node_variable}),\n"
+            f"  not runtime(Package)"
+        ).replace(f'"{placeholder}"', f"{node_variable}")
+
+        constraint_spec = spack.spec.Spec(constraint_str)
+        assert constraint_spec.name is None, "only anonymous constraint specs are accepted"
+
+        constraint_spec.name = placeholder
+        constraint_clauses = self._setup.spec_clauses(constraint_spec, body=False)
+        for clause in constraint_clauses:
+            if clause.args[0] == "node_compiler_version_satisfies":
+                self._setup.compiler_version_constraints.add(constraint_spec.compiler)
+                args = f'"{constraint_spec.compiler.name}", "{constraint_spec.compiler.versions}"'
+                head_str = f"propagate({node_variable}, node_compiler_version_satisfies({args}))"
+                rule = f"{head_str} :-\n{body_str}.\n\n"
+                self.rules.append(rule)
+
+        self.reset()
+
     def consume_facts(self):
         """Consume the facts collected by this object, and emits rules and
         facts for the runtimes.

lib/spack/spack/solver/concretize.lp

@@ -811,37 +811,6 @@ node_has_variant(node(ID, Package), Variant) :-
   pkg_fact(Package, variant(Variant)),
   attr("node", node(ID, Package)).
 
-% Variant propagation is forwarded to dependencies
-attr("variant_propagation_candidate", PackageNode, Variant, Value, Source) :-
-  attr("node", PackageNode),
-  depends_on(ParentNode, PackageNode),
-  attr("variant_value", node(_, Source), Variant, Value),
-  attr("variant_propagation_candidate", ParentNode, Variant, _, Source).
-
-% If the node is a candidate, and it has the variant and value,
-% then those variant and value should be propagated
-attr("variant_propagate", node(ID, Package), Variant, Value, Source) :-
-  attr("variant_propagation_candidate", node(ID, Package), Variant, Value, Source),
-  node_has_variant(node(ID, Package), Variant),
-  pkg_fact(Package, variant_possible_value(Variant, Value)),
-  not attr("variant_set", node(ID, Package), Variant).
-
-% Propagate the value, if there is the corresponding attribute
-attr("variant_value", PackageNode, Variant, Value) :- attr("variant_propagate", PackageNode, Variant, Value, _).
-
-% If a variant is propagated, we cannot have extraneous values (this is for multi valued variants)
-variant_is_propagated(PackageNode, Variant) :- attr("variant_propagate", PackageNode, Variant, _, _).
-:- variant_is_propagated(PackageNode, Variant),
-   attr("variant_value", PackageNode, Variant, Value),
-   not attr("variant_propagate", PackageNode, Variant, Value, _).
-
-% Cannot receive different values from different sources on the same variant
-error(100, "{0} and {1} cannot both propagate variant '{2}' to package {3} with values '{4}' and '{5}'", Source1, Source2, Variant, Package, Value1, Value2) :-
-  attr("variant_propagate", node(X, Package), Variant, Value1, Source1),
-  attr("variant_propagate", node(X, Package), Variant, Value2, Source2),
-  node_has_variant(node(X, Package), Variant),
-  Value1 < Value2, Source1 < Source2.
-
 % a variant cannot be set if it is not a variant on the package
 error(100, "Cannot set variant '{0}' for package '{1}' because the variant condition cannot be satisfied for the given spec", Variant, Package)
   :- attr("variant_set", node(X, Package), Variant),
@@ -919,7 +888,7 @@ variant_not_default(node(ID, Package), Variant, Value)
     % variants set explicitly on the CLI don't count as non-default
     not attr("variant_set", node(ID, Package), Variant, Value),
     % variant values forced by propagation don't count as non-default
-    not attr("variant_propagate", node(ID, Package), Variant, Value, _),
+    not propagate(node(ID, Package), variant_value(Variant, Value)),
     % variants set on externals that we could use don't count as non-default
     % this makes spack prefer to use an external over rebuilding with the
     % default configuration
@@ -932,7 +901,7 @@ variant_default_not_used(node(ID, Package), Variant, Value)
   :- variant_default_value(Package, Variant, Value),
      node_has_variant(node(ID, Package), Variant),
      not attr("variant_value", node(ID, Package), Variant, Value),
-     not attr("variant_propagate", node(ID, Package), Variant, _, _),
+     not propagate(node(ID, Package), variant_value(Variant, _)),
      attr("node", node(ID, Package)).
 
 % The variant is set in an external spec
@@ -989,6 +958,67 @@ pkg_fact(Package, variant_single_value("dev_path"))
 #defined variant_default_value/3.
 #defined variant_default_value_from_packages_yaml/3.
 
+%-----------------------------------------------------------------------------
+% Propagation semantics
+%-----------------------------------------------------------------------------
+
+% Propagation roots have a corresponding attr("propagate", ...)
+propagate(RootNode, PropagatedAttribute) :- attr("propagate", RootNode, PropagatedAttribute).
+
+% Propagate an attribute along edges to child nodes
+propagate(ChildNode, PropagatedAttribute) :-
+  propagate(ParentNode, PropagatedAttribute),
+  depends_on(ParentNode, ChildNode).
+
+%-----------------------------------------------------------------------------
+% Activation of propagated values
+%-----------------------------------------------------------------------------
+
+%----
+% Variants
+%----
+
+% If a variant is propagated, and can be accepted, set its value
+attr("variant_value", node(ID, Package), Variant, Value) :-
+  propagate(node(ID, Package), variant_value(Variant, Value)),
+  node_has_variant(node(ID, Package), Variant),
+  pkg_fact(Package, variant_possible_value(Variant, Value)),
+  not attr("variant_set", node(ID, Package), Variant).
+
+% If a variant is propagated, we cannot have extraneous values
+variant_is_propagated(PackageNode, Variant) :-
+  attr("variant_value", PackageNode, Variant, Value),
+  propagate(PackageNode, variant_value(Variant, Value)),
+  not attr("variant_set", PackageNode, Variant).
+
+:- variant_is_propagated(PackageNode, Variant),
+   attr("variant_value", PackageNode, Variant, Value),
+   not propagate(PackageNode, variant_value(Variant, Value)).
+
+%----
+% Compiler constraints
+%----
+
+attr("node_compiler_version_satisfies", node(ID, Package), Compiler, Version) :-
+  propagate(node(ID, Package), node_compiler_version_satisfies(Compiler, Version)),
+  node_compiler(node(ID, Package), CompilerID),
+  compiler_name(CompilerID, Compiler),
+  not runtime(Package),
+  not external(Package).
+
+%-----------------------------------------------------------------------------
+% Runtimes
+%-----------------------------------------------------------------------------
+
+% Check whether the DAG has any built package
+has_built_packages() :- build(X), not external(X).
+
+% If we build packages, the runtime nodes must use an available compiler
+1 { node_compiler(PackageNode, CompilerID) : build(PackageNode), not external(PackageNode) } :-
+  has_built_packages(),
+  runtime(RuntimePackage),
+  node_compiler(node(_, RuntimePackage), CompilerID).
+
 %-----------------------------------------------------------------------------
 % Platform semantics
 %-----------------------------------------------------------------------------
@@ -1090,10 +1120,18 @@ attr("node_target", PackageNode, Target)
  :- attr("node", PackageNode), attr("node_target_set", PackageNode, Target).
 
 % each node has the weight of its assigned target
-node_target_weight(node(ID, Package), Weight)
- :- attr("node", node(ID, Package)),
-    attr("node_target", node(ID, Package), Target),
-    target_weight(Target, Weight).
+target_weight(Target, 0)
+ :- attr("node", PackageNode),
+    attr("node_target", PackageNode, Target),
+    attr("node_target_set", PackageNode, Target).
+
+node_target_weight(PackageNode, MinWeight)
+ :- attr("node", PackageNode),
+    attr("node_target", PackageNode, Target),
+    target(Target),
+    MinWeight = #min { Weight : target_weight(Target, Weight) }.
+
+:- attr("node_target", PackageNode, Target), not node_target_weight(PackageNode, _).
 
 % compatibility rules for targets among nodes
 node_target_match(ParentNode, DependencyNode)
@@ -1155,12 +1193,12 @@ error(10, "No valid compiler for {0} satisfies '%{1}'", Package, Compiler)
 
 % If the compiler of a node must satisfy a constraint, then its version
 % must be chosen among the ones that satisfy said constraint
-error(100, "No valid version for '{0}' compiler '{1}' satisfies '@{2}'", Package, Compiler, Constraint)
+error(100, "Package {0} cannot satisfy '%{1}@{2}'", Package, Compiler, Constraint)
   :- attr("node", node(X, Package)),
      attr("node_compiler_version_satisfies", node(X, Package), Compiler, Constraint),
-		 not compiler_version_satisfies(Compiler, Constraint, _).
+	 not compiler_version_satisfies(Compiler, Constraint, _).
 
-error(100, "No valid version for '{0}' compiler '{1}' satisfies '@{2}'", Package, Compiler, Constraint)
+error(100, "Package {0} cannot satisfy '%{1}@{2}'", Package, Compiler, Constraint)
   :- attr("node", node(X, Package)),
      attr("node_compiler_version_satisfies", node(X, Package), Compiler, Constraint),
      not compiler_version_satisfies(Compiler, Constraint, ID),
@@ -1345,8 +1383,10 @@ build(PackageNode) :- not attr("hash", PackageNode, _), attr("node", PackageNode
 % topmost-priority criterion to reuse what is installed.
 %
 % The priority ranges are:
-%   200+        Shifted priorities for build nodes; correspond to priorities 0 - 99.
-%   100 - 199   Unshifted priorities. Currently only includes minimizing #builds.
+%   1000+       Optimizations for concretization errors
+%   300 - 1000  Highest priority optimizations for valid solutions
+%   200 - 299   Shifted priorities for build nodes; correspond to priorities 0 - 99.
+%   100 - 199   Unshifted priorities. Currently only includes minimizing #builds and minimizing dupes.
 %   0   -  99   Priorities for non-built nodes.
 build_priority(PackageNode, 200) :- build(PackageNode), attr("node", PackageNode).
 build_priority(PackageNode, 0)   :- not build(PackageNode), attr("node", PackageNode).
@@ -1394,6 +1434,16 @@ build_priority(PackageNode, 0)   :- not build(PackageNode), attr("node", Package
 %   2. a `#minimize{ 0@2 : #true }.` statement that ensures the criterion
 %      is displayed (clingo doesn't display sums over empty sets by default)
 
+% A condition group specifies one or more specs that must be satisfied.
+% Specs declared first are preferred, so we assign increasing weights and
+% minimize the weights.
+opt_criterion(310, "requirement weight").
+#minimize{ 0@310: #true }.
+#minimize {
+    Weight@310,PackageNode,Group
+    : requirement_weight(PackageNode, Group, Weight)
+}.
+
 % Try hard to reuse installed packages (i.e., minimize the number built)
 opt_criterion(110, "number of packages to build (vs. reuse)").
 #minimize { 0@110: #true }.
@@ -1405,18 +1455,6 @@ opt_criterion(100, "number of nodes from the same package").
 #minimize { ID@100,Package : attr("virtual_node", node(ID, Package)) }.
 #defined optimize_for_reuse/0.
 
-% A condition group specifies one or more specs that must be satisfied.
-% Specs declared first are preferred, so we assign increasing weights and
-% minimize the weights.
-opt_criterion(75, "requirement weight").
-#minimize{ 0@275: #true }.
-#minimize{ 0@75: #true }.
-#minimize {
-    Weight@75+Priority,PackageNode,Group
-    : requirement_weight(PackageNode, Group, Weight),
-      build_priority(PackageNode, Priority)
-}.
-
 % Minimize the number of deprecated versions being used
 opt_criterion(73, "deprecated versions used").
 #minimize{ 0@273: #true }.
@@ -1496,7 +1534,7 @@ opt_criterion(45, "preferred providers (non-roots)").
 }.
 
 % Try to minimize the number of compiler mismatches in the DAG.
-opt_criterion(40, "compiler mismatches that are not from CLI").
+opt_criterion(40, "compiler mismatches that are not required").
 #minimize{ 0@240: #true }.
 #minimize{ 0@40: #true }.
 #minimize{
@@ -1506,7 +1544,7 @@ opt_criterion(40, "compiler mismatches that are not from CLI").
       not runtime(Dependency)
 }.
 
-opt_criterion(39, "compiler mismatches that are not from CLI").
+opt_criterion(39, "compiler mismatches that are required").
 #minimize{ 0@239: #true }.
 #minimize{ 0@39: #true }.
 #minimize{

lib/spack/spack/solver/heuristic.lp

@@ -4,21 +4,35 @@
 % SPDX-License-Identifier: (Apache-2.0 OR MIT)
 
 %=============================================================================
-% Heuristic to speed-up solves (node with ID 0)
+% Heuristic to speed-up solves
 %=============================================================================
 
+% No duplicates by default (most of them will be true)
+#heuristic attr("node",         node(PackageID, Package)). [100, init]
+#heuristic attr("node",         node(PackageID, Package)). [  2, factor]
+#heuristic attr("virtual_node", node(VirtualID, Virtual)). [100, init]
+#heuristic attr("node",         node(1..X-1, Package)) : max_dupes(Package, X), not virtual(Package), X > 1. [-1, sign]
+#heuristic attr("virtual_node", node(1..X-1, Package)) : max_dupes(Package, X), virtual(Package)    , X > 1. [-1, sign]
 
-%-----------------
-% Domain heuristic
-%-----------------
+% Pick preferred version
+#heuristic attr("version", node(PackageID, Package), Version) : pkg_fact(Package, version_declared(Version, Weight)), attr("node", node(PackageID, Package)).             [40, init]
+#heuristic version_weight(node(PackageID, Package), 0)        : pkg_fact(Package, version_declared(Version, 0     )), attr("node", node(PackageID, Package)).             [ 1, sign]
+#heuristic attr("version", node(PackageID, Package), Version) : pkg_fact(Package, version_declared(Version, 0     )), attr("node", node(PackageID, Package)).             [ 1, sign]
+#heuristic attr("version", node(PackageID, Package), Version) : pkg_fact(Package, version_declared(Version, Weight)), attr("node", node(PackageID, Package)), Weight > 0. [-1, sign]
 
-% Root node
-#heuristic attr("version", node(0, Package), Version) : pkg_fact(Package, version_declared(Version, 0)), attr("root", node(0, Package)). [35, true]
-#heuristic version_weight(node(0, Package), 0) : pkg_fact(Package, version_declared(Version, 0)), attr("root", node(0, Package)). [35, true]
-#heuristic attr("variant_value", node(0, Package), Variant, Value) : variant_default_value(Package, Variant, Value), attr("root", node(0, Package)). [35, true]
-#heuristic attr("node_target", node(0, Package), Target) : target_weight(Target, 0), attr("root", node(0, Package)). [35, true]
-#heuristic node_target_weight(node(0, Package), 0) : attr("root", node(0, Package)). [35, true]
-#heuristic node_compiler(node(0, Package), CompilerID) : compiler_weight(ID, 0), compiler_id(ID), attr("root", node(0, Package)). [35, true]
+% Use default variants
+#heuristic attr("variant_value", node(PackageID, Package), Variant, Value) : variant_default_value(Package, Variant, Value),     attr("node", node(PackageID, Package)). [40, true]
+#heuristic attr("variant_value", node(PackageID, Package), Variant, Value) : not variant_default_value(Package, Variant, Value), attr("node", node(PackageID, Package)). [40, false]
 
-% Providers
-#heuristic attr("node", node(0, Package)) : default_provider_preference(Virtual, Package, 0), possible_in_link_run(Package). [30, true]
+% Use default operating system and platform
+#heuristic attr("node_os", node(PackageID, Package), OS) : os(OS, 0), attr("root", node(PackageID, Package)). [40, true]
+#heuristic attr("node_platform", node(PackageID, Package), Platform) : allowed_platform(Platform), attr("root", node(PackageID, Package)). [40, true]
+
+% Use default targets
+#heuristic attr("node_target", node(PackageID, Package), Target) : target_weight(Target, Weight), attr("node", node(PackageID, Package)). [30, init]
+#heuristic attr("node_target", node(PackageID, Package), Target) : target_weight(Target, Weight), attr("node", node(PackageID, Package)). [ 2, factor]
+#heuristic attr("node_target", node(PackageID, Package), Target) : target_weight(Target,      0), attr("node", node(PackageID, Package)). [ 1, sign]
+#heuristic attr("node_target", node(PackageID, Package), Target) : target_weight(Target, Weight), attr("node", node(PackageID, Package)), Weight > 0. [-1, sign]
+
+% Use the default compilers
+#heuristic node_compiler(node(PackageID, Package), ID) : compiler_weight(ID, 0), compiler_id(ID), attr("node", node(PackageID, Package)). [30, init]

lib/spack/spack/solver/heuristic_separate.lp

@@ -1,24 +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)
-
-%=============================================================================
-% Heuristic to speed-up solves (node with ID > 0)
-%=============================================================================
-
-% node(ID, _)
-#heuristic attr("version", node(ID, Package), Version) : pkg_fact(Package, version_declared(Version, 0)), attr("node", node(ID, Package)), ID > 0. [25-5*ID, true]
-#heuristic version_weight(node(ID, Package), 0) : pkg_fact(Package, version_declared(Version, 0)), attr("node", node(ID, Package)), ID > 0. [25-5*ID, true]
-#heuristic attr("variant_value", node(ID, Package), Variant, Value) : variant_default_value(Package, Variant, Value), attr("node", node(ID, Package)), ID > 0. [25-5*ID, true]
-#heuristic attr("node_target", node(ID, Package), Target) : pkg_fact(Package, target_weight(Target, 0)), attr("node", node(ID, Package)), ID > 0. [25-5*ID, true]
-#heuristic node_target_weight(node(ID, Package), 0) : attr("node", node(ID, Package)), ID > 0. [25-5*ID, true]
-#heuristic node_compiler(node(ID, Package), CompilerID) : compiler_weight(CompilerID, 0), compiler_id(CompilerID), attr("node", node(ID, Package)), ID > 0. [25-5*ID, true]
-
-% node(ID, _), split build dependencies
-#heuristic attr("version", node(ID, Package), Version) : pkg_fact(Package, version_declared(Version, 0)), attr("node", node(ID, Package)), multiple_unification_sets(Package), ID > 0. [25, true]
-#heuristic version_weight(node(ID, Package), 0) : pkg_fact(Package, version_declared(Version, 0)), attr("node", node(ID, Package)), multiple_unification_sets(Package), ID > 0. [25, true]
-#heuristic attr("variant_value", node(ID, Package), Variant, Value) : variant_default_value(Package, Variant, Value), attr("node", node(ID, Package)), multiple_unification_sets(Package), ID > 0. [25, true]
-#heuristic attr("node_target", node(ID, Package), Target) : pkg_fact(Package, target_weight(Target, 0)), attr("node", node(ID, Package)), multiple_unification_sets(Package), ID > 0. [25, true]
-#heuristic node_target_weight(node(ID, Package), 0) : attr("node", node(ID, Package)), multiple_unification_sets(Package), ID > 0. [25, true]
-#heuristic node_compiler(node(ID, Package), CompilerID) : compiler_weight(CompilerID, 0), compiler_id(CompilerID), attr("node", node(ID, Package)), multiple_unification_sets(Package), ID > 0. [25, true]

lib/spack/spack/solver/libc_compatibility.lp

@@ -10,15 +10,13 @@
 %=============================================================================
 
 % A package cannot be reused if the libc is not compatible with it
-:- provider(node(X, LibcPackage), node(0, "libc")),
-   attr("version", node(X, LibcPackage), LibcVersion),
-   attr("hash", node(R, ReusedPackage), Hash),
-   % Libc packages can be reused without the "compatible_libc" attribute
-   ReusedPackage != LibcPackage,
-   not attr("compatible_libc", node(R, ReusedPackage), LibcPackage, LibcVersion).
-
-% Check whether the DAG has any built package
-has_built_packages() :- build(X), not external(X).
+error(100, "Cannot reuse {0} since we cannot determine libc compatibility", ReusedPackage)
+  :- provider(node(X, LibcPackage), node(0, "libc")),
+     attr("version", node(X, LibcPackage), LibcVersion),
+     attr("hash", node(R, ReusedPackage), Hash),
+     % Libc packages can be reused without the "compatible_libc" attribute
+     ReusedPackage != LibcPackage,
+     not attr("compatible_libc", node(R, ReusedPackage), LibcPackage, LibcVersion).
 
 % A libc is needed in the DAG
 :- has_built_packages(), not provider(_, node(0, "libc")).

lib/spack/spack/solver/os_compatibility.lp

@@ -12,6 +12,7 @@
 %=============================================================================
 
 % macOS
+os_compatible("sequoia", "sonoma").
 os_compatible("sonoma", "ventura").
 os_compatible("ventura", "monterey").
 os_compatible("monterey", "bigsur").

lib/spack/spack/spec.py

@@ -2045,6 +2045,18 @@ def to_node_dict(self, hash=ht.dag_hash):
         if params:
             d["parameters"] = params
 
+        if params and not self.concrete:
+            flag_names = [
+                name
+                for name, flags in self.compiler_flags.items()
+                if any(x.propagate for x in flags)
+            ]
+            d["propagate"] = sorted(
+                itertools.chain(
+                    [v.name for v in self.variants.values() if v.propagate], flag_names
+                )
+            )
+
         if self.external:
             d["external"] = syaml.syaml_dict(
                 [
@@ -2217,16 +2229,10 @@ def node_dict_with_hashes(self, hash=ht.dag_hash):
         spec is concrete, the full hash is added as well.  If 'build' is in
         the hash_type, the build hash is also added."""
         node = self.to_node_dict(hash)
+        # All specs have at least a DAG hash
         node[ht.dag_hash.name] = self.dag_hash()
 
-        # dag_hash is lazily computed -- but if we write a spec out, we want it
-        # to be included. This is effectively the last chance we get to compute
-        # it accurately.
-        if self.concrete:
-            # all specs have at least a DAG hash
-            node[ht.dag_hash.name] = self.dag_hash()
-
-        else:
+        if not self.concrete:
             node["concrete"] = False
 
         # we can also give them other hash types if we want
@@ -4164,29 +4170,21 @@ def __getitem__(self, name: str):
             csv = query_parameters.pop().strip()
             query_parameters = re.split(r"\s*,\s*", csv)
 
-        # In some cases a package appears multiple times in the same DAG for *distinct*
-        # specs. For example, a build-type dependency may itself depend on a package
-        # the current spec depends on, but their specs may differ. Therefore we iterate
-        # in an order here that prioritizes the build, test and runtime dependencies;
-        # only when we don't find the package do we consider the full DAG.
         order = lambda: itertools.chain(
-            self.traverse(deptype="link"),
-            self.dependencies(deptype=dt.BUILD | dt.RUN | dt.TEST),
-            self.traverse(),  # fall back to a full search
+            self.traverse_edges(deptype=dt.LINK, order="breadth", cover="edges"),
+            self.edges_to_dependencies(depflag=dt.BUILD | dt.RUN | dt.TEST),
+            self.traverse_edges(deptype=dt.ALL, order="breadth", cover="edges"),
         )
 
+        # Consider runtime dependencies and direct build/test deps before transitive dependencies,
+        # and prefer matches closest to the root.
         try:
             child: Spec = next(
-                itertools.chain(
-                    # Regular specs
-                    (x for x in order() if x.name == name),
-                    (
-                        x
-                        for x in order()
-                        if (not x.virtual)
-                        and any(name in edge.virtuals for edge in x.edges_from_dependents())
-                    ),
-                    (x for x in order() if (not x.virtual) and x.package.provides(name)),
+                e.spec
+                for e in itertools.chain(
+                    (e for e in order() if e.spec.name == name or name in e.virtuals),
+                    # for historical reasons
+                    (e for e in order() if e.spec.concrete and e.spec.package.provides(name)),
                 )
             )
         except StopIteration:
@@ -4428,9 +4426,12 @@ def format_attribute(match_object: Match) -> str:
                 if part.startswith("_"):
                     raise SpecFormatStringError("Attempted to format private attribute")
                 else:
-                    if part == "variants" and isinstance(current, vt.VariantMap):
+                    if isinstance(current, vt.VariantMap):
                         # subscript instead of getattr for variant names
-                        current = current[part]
+                        try:
+                            current = current[part]
+                        except KeyError:
+                            raise SpecFormatStringError(f"Variant '{part}' does not exist")
                     else:
                         # aliases
                         if part == "arch":
@@ -5004,13 +5005,17 @@ def from_node_dict(cls, node):
         else:
             spec.compiler = None
 
+        propagated_names = node.get("propagate", [])
         for name, values in node.get("parameters", {}).items():
+            propagate = name in propagated_names
             if name in _valid_compiler_flags:
                 spec.compiler_flags[name] = []
                 for val in values:
-                    spec.compiler_flags.add_flag(name, val, False)
+                    spec.compiler_flags.add_flag(name, val, propagate)
             else:
-                spec.variants[name] = vt.MultiValuedVariant.from_node_dict(name, values)
+                spec.variants[name] = vt.MultiValuedVariant.from_node_dict(
+                    name, values, propagate=propagate
+                )
 
         spec.external_path = None
         spec.external_modules = None

lib/spack/spack/stage.py

@@ -13,7 +13,7 @@
 import stat
 import sys
 import tempfile
-from typing import Callable, Dict, Iterable, Optional, Set
+from typing import Callable, Dict, Iterable, List, Optional, Set
 
 import llnl.string
 import llnl.util.lang
@@ -40,6 +40,7 @@
 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
@@ -346,8 +347,6 @@ class Stage(LockableStagingDir):
     similar, and are intended to persist for only one run of spack.
     """
 
-    #: Most staging is managed by Spack. DIYStage is one exception.
-    needs_fetching = True
     requires_patch_success = True
 
     def __init__(
@@ -536,32 +535,29 @@ def generate_fetchers():
                 for fetcher in dynamic_fetchers:
                     yield fetcher
 
-        def print_errors(errors):
-            for msg in errors:
-                tty.debug(msg)
-
-        errors = []
+        errors: List[str] = []
         for fetcher in generate_fetchers():
             try:
                 fetcher.stage = self
                 self.fetcher = fetcher
                 self.fetcher.fetch()
                 break
-            except spack.fetch_strategy.NoCacheError:
+            except fs.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("Fetching from {0} failed.".format(fetcher))
-                tty.debug(e)
+                errors.append(f"{fetcher}: {e.__class__.__name__}: {e}")
                 continue
         else:
-            print_errors(errors)
-
             self.fetcher = self.default_fetcher
-            default_msg = "All fetchers failed for {0}".format(self.name)
-            raise spack.error.FetchError(err_msg or default_msg, None)
-
-        print_errors(errors)
+            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)
+            )
 
     def steal_source(self, dest):
         """Copy the source_path directory in its entirety to directory dest
@@ -772,8 +768,6 @@ def __init__(self):
                 "cache_mirror",
                 "steal_source",
                 "disable_mirrors",
-                "needs_fetching",
-                "requires_patch_success",
             ]
         )
 
@@ -812,6 +806,10 @@ def path(self):
     def archive_file(self):
         return self[0].archive_file
 
+    @property
+    def requires_patch_success(self):
+        return self[0].requires_patch_success
+
     @property
     def keep(self):
         return self[0].keep
@@ -822,64 +820,7 @@ def keep(self, value):
             item.keep = value
 
 
-class DIYStage:
-    """
-    Simple class that allows any directory to be a spack stage.  Consequently,
-    it does not expect or require that the source path adhere to the standard
-    directory naming convention.
-    """
-
-    needs_fetching = False
-    requires_patch_success = False
-
-    def __init__(self, path):
-        if path is None:
-            raise ValueError("Cannot construct DIYStage without a path.")
-        elif not os.path.isdir(path):
-            raise StagePathError("The stage path directory does not exist:", path)
-
-        self.archive_file = None
-        self.path = path
-        self.source_path = path
-        self.created = True
-
-    # DIY stages do nothing as context managers.
-    def __enter__(self):
-        pass
-
-    def __exit__(self, exc_type, exc_val, exc_tb):
-        pass
-
-    def fetch(self, *args, **kwargs):
-        tty.debug("No need to fetch for DIY.")
-
-    def check(self):
-        tty.debug("No checksum needed for DIY.")
-
-    def expand_archive(self):
-        tty.debug("Using source directory: {0}".format(self.source_path))
-
-    @property
-    def expanded(self):
-        """Returns True since the source_path must exist."""
-        return True
-
-    def restage(self):
-        raise RestageError("Cannot restage a DIY stage.")
-
-    def create(self):
-        self.created = True
-
-    def destroy(self):
-        # No need to destroy DIY stage.
-        pass
-
-    def cache_local(self):
-        tty.debug("Sources for DIY stages are not cached")
-
-
 class DevelopStage(LockableStagingDir):
-    needs_fetching = False
     requires_patch_success = False
 
     def __init__(self, name, dev_path, reference_link):
@@ -1245,7 +1186,7 @@ def _fetch_and_checksum(url, options, keep_stage, action_fn=None):
             # Checksum the archive and add it to the list
             checksum = spack.util.crypto.checksum(hashlib.sha256, stage.archive_file)
         return checksum, None
-    except FailedDownloadError:
+    except fs.FailedDownloadError:
         return None, f"[WORKER] Failed to fetch {url}"
     except Exception as e:
         return None, f"[WORKER] Something failed on {url}, skipping.  ({e})"
@@ -1265,7 +1206,3 @@ 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

lib/spack/spack/store.py

@@ -371,7 +371,6 @@ def use_store(
         data.update(extra_data)
 
     # Swap the store with the one just constructed and return it
-    ensure_singleton_created()
     spack.config.CONFIG.push_scope(
         spack.config.InternalConfigScope(name=scope_name, data={"config": {"install_tree": data}})
     )

lib/spack/spack/test/architecture.py

@@ -218,10 +218,12 @@ def test_satisfy_strict_constraint_when_not_concrete(architecture_tuple, constra
     str(archspec.cpu.host().family) != "x86_64", reason="tests are for x86_64 uarch ranges"
 )
 def test_concretize_target_ranges(root_target_range, dep_target_range, result, monkeypatch):
-    spec = Spec(f"a %gcc@10 foobar=bar target={root_target_range} ^b target={dep_target_range}")
+    spec = Spec(
+        f"pkg-a %gcc@10 foobar=bar target={root_target_range} ^pkg-b target={dep_target_range}"
+    )
     with spack.concretize.disable_compiler_existence_check():
         spec.concretize()
-    assert spec.target == spec["b"].target == result
+    assert spec.target == spec["pkg-b"].target == result
 
 
 @pytest.mark.parametrize(

lib/spack/spack/test/audit.py

@@ -19,8 +19,6 @@
         (["missing-dependency"], ["PKG-DIRECTIVES", "PKG-PROPERTIES"]),
         # The package use a non existing variant in a depends_on directive
         (["wrong-variant-in-depends-on"], ["PKG-DIRECTIVES", "PKG-PROPERTIES"]),
-        # This package has a GitHub pull request commit patch URL
-        (["invalid-github-pull-commits-patch-url"], ["PKG-DIRECTIVES", "PKG-PROPERTIES"]),
         # This package has a GitHub patch URL without full_index=1
         (["invalid-github-patch-url"], ["PKG-DIRECTIVES", "PKG-PROPERTIES"]),
         # This package has invalid GitLab patch URLs

lib/spack/spack/test/bootstrap.py

@@ -228,3 +228,25 @@ def test_source_is_disabled(mutable_config):
     spack.config.add("bootstrap:trusted:{0}:{1}".format(conf["name"], False))
     with pytest.raises(ValueError):
         spack.bootstrap.core.source_is_enabled_or_raise(conf)
+
+
+@pytest.mark.regression("45247")
+def test_use_store_does_not_try_writing_outside_root(tmp_path, monkeypatch, mutable_config):
+    """Tests that when we use the 'use_store' context manager, there is no attempt at creating
+    a Store outside the given root.
+    """
+    initial_store = mutable_config.get("config:install_tree:root")
+    user_store = tmp_path / "store"
+
+    fn = spack.store.Store.__init__
+
+    def _checked_init(self, root, *args, **kwargs):
+        fn(self, root, *args, **kwargs)
+        assert self.root == str(user_store)
+
+    monkeypatch.setattr(spack.store.Store, "__init__", _checked_init)
+
+    spack.store.reinitialize()
+    with spack.store.use_store(user_store):
+        assert spack.config.CONFIG.get("config:install_tree:root") == str(user_store)
+    assert spack.config.CONFIG.get("config:install_tree:root") == initial_store

lib/spack/spack/test/build_environment.py

@@ -457,14 +457,14 @@ def test_parallel_false_is_not_propagating(default_mock_concretization):
     # a foobar=bar (parallel = False)
     # |
     # b (parallel =True)
-    s = default_mock_concretization("a foobar=bar")
+    s = default_mock_concretization("pkg-a foobar=bar")
 
     spack.build_environment.set_package_py_globals(s.package, context=Context.BUILD)
-    assert s["a"].package.module.make_jobs == 1
+    assert s["pkg-a"].package.module.make_jobs == 1
 
-    spack.build_environment.set_package_py_globals(s["b"].package, context=Context.BUILD)
-    assert s["b"].package.module.make_jobs == spack.build_environment.determine_number_of_jobs(
-        parallel=s["b"].package.parallel
+    spack.build_environment.set_package_py_globals(s["pkg-b"].package, context=Context.BUILD)
+    assert s["pkg-b"].package.module.make_jobs == spack.build_environment.determine_number_of_jobs(
+        parallel=s["pkg-b"].package.parallel
     )
 
 
@@ -560,7 +560,7 @@ def test_dirty_disable_module_unload(config, mock_packages, working_env, mock_mo
     """Test that on CRAY platform 'module unload' is not called if the 'dirty'
     option is on.
     """
-    s = spack.spec.Spec("a").concretized()
+    s = spack.spec.Spec("pkg-a").concretized()
 
     # If called with "dirty" we don't unload modules, so no calls to the
     # `module` function on Cray

lib/spack/spack/test/build_systems.py

@@ -97,7 +97,7 @@ def test_negative_ninja_check(self, input_dir, test_dir, concretize_and_setup):
 @pytest.mark.usefixtures("config", "mock_packages")
 class TestAutotoolsPackage:
     def test_with_or_without(self, default_mock_concretization):
-        s = default_mock_concretization("a")
+        s = default_mock_concretization("pkg-a")
         options = s.package.with_or_without("foo")
 
         # Ensure that values that are not representing a feature
@@ -129,7 +129,7 @@ def activate(value):
         assert "--without-lorem-ipsum" in options
 
     def test_none_is_allowed(self, default_mock_concretization):
-        s = default_mock_concretization("a foo=none")
+        s = default_mock_concretization("pkg-a foo=none")
         options = s.package.with_or_without("foo")
 
         # Ensure that values that are not representing a feature

lib/spack/spack/test/buildtask.py

@@ -12,21 +12,21 @@
 
 def test_build_task_errors(install_mockery):
     with pytest.raises(ValueError, match="must be a package"):
-        inst.BuildTask("abc", None, False, 0, 0, 0, [])
+        inst.BuildTask("abc", None, False, 0, 0, 0, set())
 
     spec = spack.spec.Spec("trivial-install-test-package")
     pkg_cls = spack.repo.PATH.get_pkg_class(spec.name)
     with pytest.raises(ValueError, match="must have a concrete spec"):
-        inst.BuildTask(pkg_cls(spec), None, False, 0, 0, 0, [])
+        inst.BuildTask(pkg_cls(spec), None, False, 0, 0, 0, set())
 
     spec.concretize()
     assert spec.concrete
     with pytest.raises(ValueError, match="must have a build request"):
-        inst.BuildTask(spec.package, None, False, 0, 0, 0, [])
+        inst.BuildTask(spec.package, None, False, 0, 0, 0, set())
 
     request = inst.BuildRequest(spec.package, {})
     with pytest.raises(inst.InstallError, match="Cannot create a build task"):
-        inst.BuildTask(spec.package, request, False, 0, 0, inst.STATUS_REMOVED, [])
+        inst.BuildTask(spec.package, request, False, 0, 0, inst.STATUS_REMOVED, set())
 
 
 def test_build_task_basics(install_mockery):
@@ -36,8 +36,8 @@ def test_build_task_basics(install_mockery):
 
     # Ensure key properties match expectations
     request = inst.BuildRequest(spec.package, {})
-    task = inst.BuildTask(spec.package, request, False, 0, 0, inst.STATUS_ADDED, [])
-    assert task.explicit  # package was "explicitly" requested
+    task = inst.BuildTask(spec.package, request, False, 0, 0, inst.STATUS_ADDED, set())
+    assert not task.explicit
     assert task.priority == len(task.uninstalled_deps)
     assert task.key == (task.priority, task.sequence)
 
@@ -58,7 +58,7 @@ def test_build_task_strings(install_mockery):
 
     # Ensure key properties match expectations
     request = inst.BuildRequest(spec.package, {})
-    task = inst.BuildTask(spec.package, request, False, 0, 0, inst.STATUS_ADDED, [])
+    task = inst.BuildTask(spec.package, request, False, 0, 0, inst.STATUS_ADDED, set())
 
     # Cover __repr__
     irep = task.__repr__()

lib/spack/spack/test/cmd/ci.py

@@ -106,24 +106,24 @@ def test_specs_staging(config, tmpdir):
 
 """
     builder = repo.MockRepositoryBuilder(tmpdir)
-    builder.add_package("g")
-    builder.add_package("f")
-    builder.add_package("e")
-    builder.add_package("d", dependencies=[("f", None, None), ("g", None, None)])
-    builder.add_package("c")
-    builder.add_package("b", dependencies=[("d", None, None), ("e", None, None)])
-    builder.add_package("a", dependencies=[("b", None, None), ("c", None, None)])
+    builder.add_package("pkg-g")
+    builder.add_package("pkg-f")
+    builder.add_package("pkg-e")
+    builder.add_package("pkg-d", dependencies=[("pkg-f", None, None), ("pkg-g", None, None)])
+    builder.add_package("pkg-c")
+    builder.add_package("pkg-b", dependencies=[("pkg-d", None, None), ("pkg-e", None, None)])
+    builder.add_package("pkg-a", dependencies=[("pkg-b", None, None), ("pkg-c", None, None)])
 
     with repo.use_repositories(builder.root):
-        spec_a = Spec("a").concretized()
+        spec_a = Spec("pkg-a").concretized()
 
         spec_a_label = ci._spec_ci_label(spec_a)
-        spec_b_label = ci._spec_ci_label(spec_a["b"])
-        spec_c_label = ci._spec_ci_label(spec_a["c"])
-        spec_d_label = ci._spec_ci_label(spec_a["d"])
-        spec_e_label = ci._spec_ci_label(spec_a["e"])
-        spec_f_label = ci._spec_ci_label(spec_a["f"])
-        spec_g_label = ci._spec_ci_label(spec_a["g"])
+        spec_b_label = ci._spec_ci_label(spec_a["pkg-b"])
+        spec_c_label = ci._spec_ci_label(spec_a["pkg-c"])
+        spec_d_label = ci._spec_ci_label(spec_a["pkg-d"])
+        spec_e_label = ci._spec_ci_label(spec_a["pkg-e"])
+        spec_f_label = ci._spec_ci_label(spec_a["pkg-f"])
+        spec_g_label = ci._spec_ci_label(spec_a["pkg-g"])
 
         spec_labels, dependencies, stages = ci.stage_spec_jobs([spec_a])
 
@@ -1290,7 +1290,7 @@ def test_ci_generate_override_runner_attrs(
 spack:
   specs:
     - flatten-deps
-    - a
+    - pkg-a
   mirrors:
     some-mirror: https://my.fake.mirror
   ci:
@@ -1307,12 +1307,12 @@ def test_ci_generate_override_runner_attrs(
         - match:
             - dependency-install
         - match:
-            - a
+            - pkg-a
           build-job:
             tags:
               - specific-a-2
         - match:
-            - a
+            - pkg-a
           build-job-remove:
             tags:
               - toplevel2
@@ -1372,8 +1372,8 @@ def test_ci_generate_override_runner_attrs(
             assert global_vars["SPACK_CHECKOUT_VERSION"] == git_version or "v0.20.0.test0"
 
             for ci_key in yaml_contents.keys():
-                if ci_key.startswith("a"):
-                    # Make sure a's attributes override variables, and all the
+                if ci_key.startswith("pkg-a"):
+                    # Make sure pkg-a's attributes override variables, and all the
                     # scripts.  Also, make sure the 'toplevel' tag doesn't
                     # appear twice, but that a's specific extra tag does appear
                     the_elt = yaml_contents[ci_key]
@@ -1830,7 +1830,7 @@ def test_ci_generate_read_broken_specs_url(
     tmpdir, mutable_mock_env_path, install_mockery, mock_packages, monkeypatch, ci_base_environment
 ):
     """Verify that `broken-specs-url` works as intended"""
-    spec_a = Spec("a")
+    spec_a = Spec("pkg-a")
     spec_a.concretize()
     a_dag_hash = spec_a.dag_hash()
 
@@ -1856,7 +1856,7 @@ def test_ci_generate_read_broken_specs_url(
 spack:
   specs:
     - flatten-deps
-    - a
+    - pkg-a
   mirrors:
     some-mirror: https://my.fake.mirror
   ci:
@@ -1864,9 +1864,9 @@ def test_ci_generate_read_broken_specs_url(
     pipeline-gen:
     - submapping:
       - match:
-          - a
+          - pkg-a
           - flatten-deps
-          - b
+          - pkg-b
           - dependency-install
         build-job:
           tags:

lib/spack/spack/test/cmd/common/arguments.py

@@ -81,14 +81,14 @@ def test_match_spec_env(mock_packages, mutable_mock_env_path):
     """
     # Initial sanity check: we are planning on choosing a non-default
     # value, so make sure that is in fact not the default.
-    check_defaults = spack.cmd.parse_specs(["a"], concretize=True)[0]
+    check_defaults = spack.cmd.parse_specs(["pkg-a"], concretize=True)[0]
     assert not check_defaults.satisfies("foobar=baz")
 
     e = ev.create("test")
-    e.add("a foobar=baz")
+    e.add("pkg-a foobar=baz")
     e.concretize()
     with e:
-        env_spec = spack.cmd.matching_spec_from_env(spack.cmd.parse_specs(["a"])[0])
+        env_spec = spack.cmd.matching_spec_from_env(spack.cmd.parse_specs(["pkg-a"])[0])
         assert env_spec.satisfies("foobar=baz")
         assert env_spec.concrete
 
@@ -96,12 +96,12 @@ def test_match_spec_env(mock_packages, mutable_mock_env_path):
 @pytest.mark.usefixtures("config")
 def test_multiple_env_match_raises_error(mock_packages, mutable_mock_env_path):
     e = ev.create("test")
-    e.add("a foobar=baz")
-    e.add("a foobar=fee")
+    e.add("pkg-a foobar=baz")
+    e.add("pkg-a foobar=fee")
     e.concretize()
     with e:
         with pytest.raises(ev.SpackEnvironmentError) as exc_info:
-            spack.cmd.matching_spec_from_env(spack.cmd.parse_specs(["a"])[0])
+            spack.cmd.matching_spec_from_env(spack.cmd.parse_specs(["pkg-a"])[0])
 
     assert "matches multiple specs" in exc_info.value.message
 
@@ -109,16 +109,16 @@ def test_multiple_env_match_raises_error(mock_packages, mutable_mock_env_path):
 @pytest.mark.usefixtures("config")
 def test_root_and_dep_match_returns_root(mock_packages, mutable_mock_env_path):
     e = ev.create("test")
-    e.add("b@0.9")
-    e.add("a foobar=bar")  # Depends on b, should choose b@1.0
+    e.add("pkg-b@0.9")
+    e.add("pkg-a foobar=bar")  # Depends on b, should choose b@1.0
     e.concretize()
     with e:
         # This query matches the root b and b as a dependency of a. In that
         # case the root instance should be preferred.
-        env_spec1 = spack.cmd.matching_spec_from_env(spack.cmd.parse_specs(["b"])[0])
+        env_spec1 = spack.cmd.matching_spec_from_env(spack.cmd.parse_specs(["pkg-b"])[0])
         assert env_spec1.satisfies("@0.9")
 
-        env_spec2 = spack.cmd.matching_spec_from_env(spack.cmd.parse_specs(["b@1.0"])[0])
+        env_spec2 = spack.cmd.matching_spec_from_env(spack.cmd.parse_specs(["pkg-b@1.0"])[0])
         assert env_spec2
 
 

lib/spack/spack/test/cmd/concretize.py

@@ -51,8 +51,8 @@ def test_concretize_root_test_dependencies_are_concretized(unify, mutable_mock_e
 
     with ev.read("test") as e:
         e.unify = unify
-        add("a")
-        add("b")
+        add("pkg-a")
+        add("pkg-b")
         concretize("--test", "root")
         assert e.matching_spec("test-dependency")
 

lib/spack/spack/test/cmd/deconcretize.py

@@ -15,26 +15,26 @@
 def test_env(mutable_mock_env_path, config, mock_packages):
     ev.create("test")
     with ev.read("test") as e:
-        e.add("a@2.0 foobar=bar ^b@1.0")
-        e.add("a@1.0 foobar=bar ^b@0.9")
+        e.add("pkg-a@2.0 foobar=bar ^pkg-b@1.0")
+        e.add("pkg-a@1.0 foobar=bar ^pkg-b@0.9")
         e.concretize()
         e.write()
 
 
 def test_deconcretize_dep(test_env):
     with ev.read("test") as e:
-        deconcretize("-y", "b@1.0")
+        deconcretize("-y", "pkg-b@1.0")
         specs = [s for s, _ in e.concretized_specs()]
 
     assert len(specs) == 1
-    assert specs[0].satisfies("a@1.0")
+    assert specs[0].satisfies("pkg-a@1.0")
 
 
 def test_deconcretize_all_dep(test_env):
     with ev.read("test") as e:
         with pytest.raises(SpackCommandError):
-            deconcretize("-y", "b")
-        deconcretize("-y", "--all", "b")
+            deconcretize("-y", "pkg-b")
+        deconcretize("-y", "--all", "pkg-b")
         specs = [s for s, _ in e.concretized_specs()]
 
     assert len(specs) == 0
@@ -42,27 +42,27 @@ def test_deconcretize_all_dep(test_env):
 
 def test_deconcretize_root(test_env):
     with ev.read("test") as e:
-        output = deconcretize("-y", "--root", "b@1.0")
+        output = deconcretize("-y", "--root", "pkg-b@1.0")
         assert "No matching specs to deconcretize" in output
         assert len(e.concretized_order) == 2
 
-        deconcretize("-y", "--root", "a@2.0")
+        deconcretize("-y", "--root", "pkg-a@2.0")
         specs = [s for s, _ in e.concretized_specs()]
 
     assert len(specs) == 1
-    assert specs[0].satisfies("a@1.0")
+    assert specs[0].satisfies("pkg-a@1.0")
 
 
 def test_deconcretize_all_root(test_env):
     with ev.read("test") as e:
         with pytest.raises(SpackCommandError):
-            deconcretize("-y", "--root", "a")
+            deconcretize("-y", "--root", "pkg-a")
 
-        output = deconcretize("-y", "--root", "--all", "b")
+        output = deconcretize("-y", "--root", "--all", "pkg-b")
         assert "No matching specs to deconcretize" in output
         assert len(e.concretized_order) == 2
 
-        deconcretize("-y", "--root", "--all", "a")
+        deconcretize("-y", "--root", "--all", "pkg-a")
         specs = [s for s, _ in e.concretized_specs()]
 
     assert len(specs) == 0

lib/spack/spack/test/cmd/env.py

@@ -28,7 +28,9 @@
 import spack.package_base
 import spack.paths
 import spack.repo
+import spack.store
 import spack.util.spack_json as sjson
+import spack.util.spack_yaml
 from spack.cmd.env import _env_create
 from spack.main import SpackCommand, SpackCommandError
 from spack.spec import Spec
@@ -501,7 +503,7 @@ def test_env_install_two_specs_same_dep(install_mockery, mock_fetch, tmpdir, cap
                 """\
 spack:
   specs:
-  - a
+  - pkg-a
   - depb
 """
             )
@@ -520,8 +522,8 @@ def test_env_install_two_specs_same_dep(install_mockery, mock_fetch, tmpdir, cap
     depb = spack.store.STORE.db.query_one("depb", installed=True)
     assert depb, "Expected depb to be installed"
 
-    a = spack.store.STORE.db.query_one("a", installed=True)
-    assert a, "Expected a to be installed"
+    a = spack.store.STORE.db.query_one("pkg-a", installed=True)
+    assert a, "Expected pkg-a to be installed"
 
 
 def test_remove_after_concretize():
@@ -825,7 +827,7 @@ def test_env_view_external_prefix(tmp_path, mutable_database, mock_packages):
         """\
 spack:
   specs:
-  - a
+  - pkg-a
   view: true
 """
     )
@@ -833,9 +835,9 @@ def test_env_view_external_prefix(tmp_path, mutable_database, mock_packages):
     external_config = io.StringIO(
         """\
 packages:
-  a:
+  pkg-a:
     externals:
-    - spec: a@2.0
+    - spec: pkg-a@2.0
       prefix: {a_prefix}
     buildable: false
 """.format(
@@ -1737,6 +1739,17 @@ def test_env_include_concrete_env_yaml(env_name):
     assert test.path in combined_yaml["include_concrete"]
 
 
+@pytest.mark.regression("45766")
+@pytest.mark.parametrize("format", ["v1", "v2", "v3"])
+def test_env_include_concrete_old_env(format, tmpdir):
+    lockfile = os.path.join(spack.paths.test_path, "data", "legacy_env", f"{format}.lock")
+    # create an env from old .lock file -- this does not update the format
+    env("create", "old-env", lockfile)
+    env("create", "--include-concrete", "old-env", "test")
+
+    assert ev.read("old-env").all_specs() == ev.read("test").all_specs()
+
+
 def test_env_bad_include_concrete_env():
     with pytest.raises(ev.SpackEnvironmentError):
         env("create", "--include-concrete", "nonexistant_env", "combined_env")
@@ -3974,7 +3987,7 @@ def test_environment_depfile_makefile(depfile_flags, expected_installs, tmpdir,
         )
 
     # Do make dry run.
-    out = make("-n", "-f", makefile, output=str)
+    out = make("-n", "-f", makefile, "SPACK=spack", output=str)
 
     specs_that_make_would_install = _parse_dry_run_package_installs(out)
 
@@ -4012,7 +4025,7 @@ def test_depfile_works_with_gitversions(tmpdir, mock_packages, monkeypatch):
         env("depfile", "-o", makefile, "--make-disable-jobserver", "--make-prefix=prefix")
 
     # Do a dry run on the generated depfile
-    out = make("-n", "-f", makefile, output=str)
+    out = make("-n", "-f", makefile, "SPACK=spack", output=str)
 
     # Check that all specs are there (without duplicates)
     specs_that_make_would_install = _parse_dry_run_package_installs(out)
@@ -4074,7 +4087,12 @@ def test_depfile_phony_convenience_targets(
 
         # Phony install/* target should install picked package and all its deps
         specs_that_make_would_install = _parse_dry_run_package_installs(
-            make("-n", picked_spec.format("install/{name}-{version}-{hash}"), output=str)
+            make(
+                "-n",
+                picked_spec.format("install/{name}-{version}-{hash}"),
+                "SPACK=spack",
+                output=str,
+            )
         )
 
         assert set(specs_that_make_would_install) == set(expected_installs)
@@ -4082,7 +4100,12 @@ def test_depfile_phony_convenience_targets(
 
         # Phony install-deps/* target shouldn't install picked package
         specs_that_make_would_install = _parse_dry_run_package_installs(
-            make("-n", picked_spec.format("install-deps/{name}-{version}-{hash}"), output=str)
+            make(
+                "-n",
+                picked_spec.format("install-deps/{name}-{version}-{hash}"),
+                "SPACK=spack",
+                output=str,
+            )
         )
 
         assert set(specs_that_make_would_install) == set(expected_installs) - {picked_package}
@@ -4142,7 +4165,7 @@ def test_spack_package_ids_variable(tmpdir, mock_packages):
     make = Executable("make")
 
     # Do dry run.
-    out = make("-n", "-C", str(tmpdir), output=str)
+    out = make("-n", "-C", str(tmpdir), "SPACK=spack", output=str)
 
     # post-install: <hash> should've been executed
     with ev.read("test") as test:

lib/spack/spack/test/cmd/find.py

@@ -69,10 +69,10 @@ def test_query_arguments():
 
     q_args = query_arguments(args)
     assert "installed" in q_args
-    assert "known" in q_args
+    assert "predicate_fn" in q_args
     assert "explicit" in q_args
     assert q_args["installed"] == ["installed"]
-    assert q_args["known"] is any
+    assert q_args["predicate_fn"] is None
     assert q_args["explicit"] is any
     assert "start_date" in q_args
     assert "end_date" not in q_args

lib/spack/spack/test/cmd/install.py

@@ -89,7 +89,7 @@ def check(pkg):
         assert pkg.run_tests
 
     monkeypatch.setattr(spack.package_base.PackageBase, "unit_test_check", check)
-    install("--test=all", "a")
+    install("--test=all", "pkg-a")
 
 
 def test_install_package_already_installed(
@@ -570,61 +570,58 @@ def test_cdash_upload_build_error(tmpdir, mock_fetch, install_mockery, capfd):
 @pytest.mark.disable_clean_stage_check
 def test_cdash_upload_clean_build(tmpdir, mock_fetch, install_mockery, capfd):
     # capfd interferes with Spack's capturing of e.g., Build.xml output
-    with capfd.disabled():
-        with tmpdir.as_cwd():
-            install("--log-file=cdash_reports", "--log-format=cdash", "a")
-            report_dir = tmpdir.join("cdash_reports")
-            assert report_dir in tmpdir.listdir()
-            report_file = report_dir.join("a_Build.xml")
-            assert report_file in report_dir.listdir()
-            content = report_file.open().read()
-            assert "</Build>" in content
-            assert "<Text>" not in content
+    with capfd.disabled(), tmpdir.as_cwd():
+        install("--log-file=cdash_reports", "--log-format=cdash", "pkg-a")
+        report_dir = tmpdir.join("cdash_reports")
+        assert report_dir in tmpdir.listdir()
+        report_file = report_dir.join("pkg-a_Build.xml")
+        assert report_file in report_dir.listdir()
+        content = report_file.open().read()
+        assert "</Build>" in content
+        assert "<Text>" not in content
 
 
 @pytest.mark.disable_clean_stage_check
 def test_cdash_upload_extra_params(tmpdir, mock_fetch, install_mockery, capfd):
     # capfd interferes with Spack's capture of e.g., Build.xml output
-    with capfd.disabled():
-        with tmpdir.as_cwd():
-            install(
-                "--log-file=cdash_reports",
-                "--log-format=cdash",
-                "--cdash-build=my_custom_build",
-                "--cdash-site=my_custom_site",
-                "--cdash-track=my_custom_track",
-                "a",
-            )
-            report_dir = tmpdir.join("cdash_reports")
-            assert report_dir in tmpdir.listdir()
-            report_file = report_dir.join("a_Build.xml")
-            assert report_file in report_dir.listdir()
-            content = report_file.open().read()
-            assert 'Site BuildName="my_custom_build - a"' in content
-            assert 'Name="my_custom_site"' in content
-            assert "-my_custom_track" in content
+    with capfd.disabled(), tmpdir.as_cwd():
+        install(
+            "--log-file=cdash_reports",
+            "--log-format=cdash",
+            "--cdash-build=my_custom_build",
+            "--cdash-site=my_custom_site",
+            "--cdash-track=my_custom_track",
+            "pkg-a",
+        )
+        report_dir = tmpdir.join("cdash_reports")
+        assert report_dir in tmpdir.listdir()
+        report_file = report_dir.join("pkg-a_Build.xml")
+        assert report_file in report_dir.listdir()
+        content = report_file.open().read()
+        assert 'Site BuildName="my_custom_build - pkg-a"' in content
+        assert 'Name="my_custom_site"' in content
+        assert "-my_custom_track" in content
 
 
 @pytest.mark.disable_clean_stage_check
 def test_cdash_buildstamp_param(tmpdir, mock_fetch, install_mockery, capfd):
     # capfd interferes with Spack's capture of e.g., Build.xml output
-    with capfd.disabled():
-        with tmpdir.as_cwd():
-            cdash_track = "some_mocked_track"
-            buildstamp_format = "%Y%m%d-%H%M-{0}".format(cdash_track)
-            buildstamp = time.strftime(buildstamp_format, time.localtime(int(time.time())))
-            install(
-                "--log-file=cdash_reports",
-                "--log-format=cdash",
-                "--cdash-buildstamp={0}".format(buildstamp),
-                "a",
-            )
-            report_dir = tmpdir.join("cdash_reports")
-            assert report_dir in tmpdir.listdir()
-            report_file = report_dir.join("a_Build.xml")
-            assert report_file in report_dir.listdir()
-            content = report_file.open().read()
-            assert buildstamp in content
+    with capfd.disabled(), tmpdir.as_cwd():
+        cdash_track = "some_mocked_track"
+        buildstamp_format = "%Y%m%d-%H%M-{0}".format(cdash_track)
+        buildstamp = time.strftime(buildstamp_format, time.localtime(int(time.time())))
+        install(
+            "--log-file=cdash_reports",
+            "--log-format=cdash",
+            "--cdash-buildstamp={0}".format(buildstamp),
+            "pkg-a",
+        )
+        report_dir = tmpdir.join("cdash_reports")
+        assert report_dir in tmpdir.listdir()
+        report_file = report_dir.join("pkg-a_Build.xml")
+        assert report_file in report_dir.listdir()
+        content = report_file.open().read()
+        assert buildstamp in content
 
 
 @pytest.mark.disable_clean_stage_check
@@ -632,38 +629,37 @@ def test_cdash_install_from_spec_json(
     tmpdir, mock_fetch, install_mockery, capfd, mock_packages, mock_archive, config
 ):
     # capfd interferes with Spack's capturing
-    with capfd.disabled():
-        with tmpdir.as_cwd():
-            spec_json_path = str(tmpdir.join("spec.json"))
+    with capfd.disabled(), tmpdir.as_cwd():
+        spec_json_path = str(tmpdir.join("spec.json"))
 
-            pkg_spec = Spec("a")
-            pkg_spec.concretize()
+        pkg_spec = Spec("pkg-a")
+        pkg_spec.concretize()
 
-            with open(spec_json_path, "w") as fd:
-                fd.write(pkg_spec.to_json(hash=ht.dag_hash))
+        with open(spec_json_path, "w") as fd:
+            fd.write(pkg_spec.to_json(hash=ht.dag_hash))
 
-            install(
-                "--log-format=cdash",
-                "--log-file=cdash_reports",
-                "--cdash-build=my_custom_build",
-                "--cdash-site=my_custom_site",
-                "--cdash-track=my_custom_track",
-                "-f",
-                spec_json_path,
-            )
+        install(
+            "--log-format=cdash",
+            "--log-file=cdash_reports",
+            "--cdash-build=my_custom_build",
+            "--cdash-site=my_custom_site",
+            "--cdash-track=my_custom_track",
+            "-f",
+            spec_json_path,
+        )
 
-            report_dir = tmpdir.join("cdash_reports")
-            assert report_dir in tmpdir.listdir()
-            report_file = report_dir.join("a_Configure.xml")
-            assert report_file in report_dir.listdir()
-            content = report_file.open().read()
-            install_command_regex = re.compile(
-                r"<ConfigureCommand>(.+)</ConfigureCommand>", re.MULTILINE | re.DOTALL
-            )
-            m = install_command_regex.search(content)
-            assert m
-            install_command = m.group(1)
-            assert "a@" in install_command
+        report_dir = tmpdir.join("cdash_reports")
+        assert report_dir in tmpdir.listdir()
+        report_file = report_dir.join("pkg-a_Configure.xml")
+        assert report_file in report_dir.listdir()
+        content = report_file.open().read()
+        install_command_regex = re.compile(
+            r"<ConfigureCommand>(.+)</ConfigureCommand>", re.MULTILINE | re.DOTALL
+        )
+        m = install_command_regex.search(content)
+        assert m
+        install_command = m.group(1)
+        assert "pkg-a@" in install_command
 
 
 @pytest.mark.disable_clean_stage_check
@@ -795,15 +791,15 @@ def test_install_no_add_in_env(tmpdir, mock_fetch, install_mockery, mutable_mock
     #                 ^libdwarf
     #         ^mpich
     #     libelf@0.8.10
-    #     a~bvv
-    #         ^b
-    #     a
-    #         ^b
+    #     pkg-a~bvv
+    #         ^pkg-b
+    #     pkg-a
+    #         ^pkg-b
     e = ev.create("test", with_view=False)
     e.add("mpileaks")
     e.add("libelf@0.8.10")  # so env has both root and dep libelf specs
-    e.add("a")
-    e.add("a ~bvv")
+    e.add("pkg-a")
+    e.add("pkg-a ~bvv")
     e.concretize()
     e.write()
     env_specs = e.all_specs()
@@ -814,9 +810,9 @@ def test_install_no_add_in_env(tmpdir, mock_fetch, install_mockery, mutable_mock
 
     # First find and remember some target concrete specs in the environment
     for e_spec in env_specs:
-        if e_spec.satisfies(Spec("a ~bvv")):
+        if e_spec.satisfies(Spec("pkg-a ~bvv")):
             a_spec = e_spec
-        elif e_spec.name == "b":
+        elif e_spec.name == "pkg-b":
             b_spec = e_spec
         elif e_spec.satisfies(Spec("mpi")):
             mpi_spec = e_spec
@@ -839,8 +835,8 @@ def test_install_no_add_in_env(tmpdir, mock_fetch, install_mockery, mutable_mock
         assert "You can add specs to the environment with 'spack add " in inst_out
 
         # Without --add, ensure that two packages "a" get installed
-        inst_out = install("a", output=str)
-        assert len([x for x in e.all_specs() if x.installed and x.name == "a"]) == 2
+        inst_out = install("pkg-a", output=str)
+        assert len([x for x in e.all_specs() if x.installed and x.name == "pkg-a"]) == 2
 
         # Install an unambiguous dependency spec (that already exists as a dep
         # in the environment) and make sure it gets installed (w/ deps),
@@ -873,7 +869,7 @@ def test_install_no_add_in_env(tmpdir, mock_fetch, install_mockery, mutable_mock
         # root of the environment as well as installed.
         assert b_spec not in e.roots()
 
-        install("--add", "b")
+        install("--add", "pkg-b")
 
         assert b_spec in e.roots()
         assert b_spec not in e.uninstalled_specs()
@@ -908,7 +904,7 @@ def test_cdash_auth_token(tmpdir, mock_fetch, install_mockery, monkeypatch, capf
     # capfd interferes with Spack's capturing
     with tmpdir.as_cwd(), capfd.disabled():
         monkeypatch.setenv("SPACK_CDASH_AUTH_TOKEN", "asdf")
-        out = install("-v", "--log-file=cdash_reports", "--log-format=cdash", "a")
+        out = install("-v", "--log-file=cdash_reports", "--log-format=cdash", "pkg-a")
         assert "Using CDash auth token from environment" in out
 
 
@@ -916,26 +912,25 @@ def test_cdash_auth_token(tmpdir, mock_fetch, install_mockery, monkeypatch, capf
 @pytest.mark.disable_clean_stage_check
 def test_cdash_configure_warning(tmpdir, mock_fetch, install_mockery, capfd):
     # capfd interferes with Spack's capturing of e.g., Build.xml output
-    with capfd.disabled():
-        with tmpdir.as_cwd():
-            # Test would fail if install raised an error.
+    with capfd.disabled(), tmpdir.as_cwd():
+        # Test would fail if install raised an error.
 
-            # Ensure that even on non-x86_64 architectures, there are no
-            # dependencies installed
-            spec = spack.spec.Spec("configure-warning").concretized()
-            spec.clear_dependencies()
-            specfile = "./spec.json"
-            with open(specfile, "w") as f:
-                f.write(spec.to_json())
+        # Ensure that even on non-x86_64 architectures, there are no
+        # dependencies installed
+        spec = Spec("configure-warning").concretized()
+        spec.clear_dependencies()
+        specfile = "./spec.json"
+        with open(specfile, "w") as f:
+            f.write(spec.to_json())
 
-            install("--log-file=cdash_reports", "--log-format=cdash", specfile)
-            # Verify Configure.xml exists with expected contents.
-            report_dir = tmpdir.join("cdash_reports")
-            assert report_dir in tmpdir.listdir()
-            report_file = report_dir.join("Configure.xml")
-            assert report_file in report_dir.listdir()
-            content = report_file.open().read()
-            assert "foo: No such file or directory" in content
+        install("--log-file=cdash_reports", "--log-format=cdash", specfile)
+        # Verify Configure.xml exists with expected contents.
+        report_dir = tmpdir.join("cdash_reports")
+        assert report_dir in tmpdir.listdir()
+        report_file = report_dir.join("Configure.xml")
+        assert report_file in report_dir.listdir()
+        content = report_file.open().read()
+        assert "foo: No such file or directory" in content
 
 
 @pytest.mark.not_on_windows("ArchSpec gives test platform debian rather than windows")
@@ -952,7 +947,7 @@ def test_compiler_bootstrap(
     assert CompilerSpec("gcc@=12.0") not in compilers.all_compiler_specs()
 
     # Test succeeds if it does not raise an error
-    install("a%gcc@=12.0")
+    install("pkg-a%gcc@=12.0")
 
 
 @pytest.mark.not_on_windows("Binary mirrors not supported on windows")
@@ -992,8 +987,8 @@ def test_compiler_bootstrap_from_binary_mirror(
     # Now make sure that when the compiler is installed from binary mirror,
     # it also gets configured as a compiler.  Test succeeds if it does not
     # raise an error
-    install("--no-check-signature", "--cache-only", "--only", "dependencies", "b%gcc@=10.2.0")
-    install("--no-cache", "--only", "package", "b%gcc@10.2.0")
+    install("--no-check-signature", "--cache-only", "--only", "dependencies", "pkg-b%gcc@=10.2.0")
+    install("--no-cache", "--only", "package", "pkg-b%gcc@10.2.0")
 
 
 @pytest.mark.not_on_windows("ArchSpec gives test platform debian rather than windows")
@@ -1013,7 +1008,7 @@ def test_compiler_bootstrap_already_installed(
 
     # Test succeeds if it does not raise an error
     install("gcc@=12.0")
-    install("a%gcc@=12.0")
+    install("pkg-a%gcc@=12.0")
 
 
 def test_install_fails_no_args(tmpdir):
@@ -1195,7 +1190,7 @@ def test_report_filename_for_cdash(install_mockery_mutable_config, mock_fetch):
     parser = argparse.ArgumentParser()
     spack.cmd.install.setup_parser(parser)
     args = parser.parse_args(
-        ["--cdash-upload-url", "https://blahblah/submit.php?project=debugging", "a"]
+        ["--cdash-upload-url", "https://blahblah/submit.php?project=debugging", "pkg-a"]
     )
     specs = spack.cmd.install.concrete_specs_from_cli(args, {})
     filename = spack.cmd.install.report_filename(args, specs)

lib/spack/spack/test/cmd/maintainers.py

@@ -121,7 +121,7 @@ def test_maintainers_list_packages(mock_packages, capfd):
 
 
 def test_maintainers_list_fails(mock_packages, capfd):
-    out = maintainers("a", fail_on_error=False)
+    out = maintainers("pkg-a", fail_on_error=False)
     assert not out
     assert maintainers.returncode == 1
 

lib/spack/spack/test/cmd/module.py

@@ -11,6 +11,7 @@
 import spack.config
 import spack.main
 import spack.modules
+import spack.spec
 import spack.store
 
 module = spack.main.SpackCommand("module")
@@ -178,8 +179,8 @@ def test_setdefault_command(mutable_database, mutable_config):
         }
     }
     spack.config.set("modules", data)
-    # Install two different versions of a package
-    other_spec, preferred = "a@1.0", "a@2.0"
+    # Install two different versions of pkg-a
+    other_spec, preferred = "pkg-a@1.0", "pkg-a@2.0"
 
     spack.spec.Spec(other_spec).concretized().package.do_install(fake=True)
     spack.spec.Spec(preferred).concretized().package.do_install(fake=True)

lib/spack/spack/test/cmd/pkg.py

@@ -28,8 +28,8 @@ def install(self, spec, prefix):
         pass
 """
 
-abc = set(("pkg-a", "pkg-b", "pkg-c"))
-abd = set(("pkg-a", "pkg-b", "pkg-d"))
+abc = {"mockpkg-a", "mockpkg-b", "mockpkg-c"}
+abd = {"mockpkg-a", "mockpkg-b", "mockpkg-d"}
 
 
 # Force all tests to use a git repository *in* the mock packages repo.
@@ -53,27 +53,33 @@ def mock_pkg_git_repo(git, tmpdir_factory):
         git("config", "user.name", "Spack Testing")
         git("-c", "commit.gpgsign=false", "commit", "-m", "initial mock repo commit")
 
-        # add commit with pkg-a, pkg-b, pkg-c packages
-        mkdirp("pkg-a", "pkg-b", "pkg-c")
-        with open("pkg-a/package.py", "w") as f:
+        # add commit with mockpkg-a, mockpkg-b, mockpkg-c packages
+        mkdirp("mockpkg-a", "mockpkg-b", "mockpkg-c")
+        with open("mockpkg-a/package.py", "w") as f:
             f.write(pkg_template.format(name="PkgA"))
-        with open("pkg-b/package.py", "w") as f:
+        with open("mockpkg-b/package.py", "w") as f:
             f.write(pkg_template.format(name="PkgB"))
-        with open("pkg-c/package.py", "w") as f:
+        with open("mockpkg-c/package.py", "w") as f:
             f.write(pkg_template.format(name="PkgC"))
-        git("add", "pkg-a", "pkg-b", "pkg-c")
-        git("-c", "commit.gpgsign=false", "commit", "-m", "add pkg-a, pkg-b, pkg-c")
+        git("add", "mockpkg-a", "mockpkg-b", "mockpkg-c")
+        git("-c", "commit.gpgsign=false", "commit", "-m", "add mockpkg-a, mockpkg-b, mockpkg-c")
 
-        # remove pkg-c, add pkg-d
-        with open("pkg-b/package.py", "a") as f:
-            f.write("\n# change pkg-b")
-        git("add", "pkg-b")
-        mkdirp("pkg-d")
-        with open("pkg-d/package.py", "w") as f:
+        # remove mockpkg-c, add mockpkg-d
+        with open("mockpkg-b/package.py", "a") as f:
+            f.write("\n# change mockpkg-b")
+        git("add", "mockpkg-b")
+        mkdirp("mockpkg-d")
+        with open("mockpkg-d/package.py", "w") as f:
             f.write(pkg_template.format(name="PkgD"))
-        git("add", "pkg-d")
-        git("rm", "-rf", "pkg-c")
-        git("-c", "commit.gpgsign=false", "commit", "-m", "change pkg-b, remove pkg-c, add pkg-d")
+        git("add", "mockpkg-d")
+        git("rm", "-rf", "mockpkg-c")
+        git(
+            "-c",
+            "commit.gpgsign=false",
+            "commit",
+            "-m",
+            "change mockpkg-b, remove mockpkg-c, add mockpkg-d",
+        )
 
     with spack.repo.use_repositories(str(repo_path)):
         yield mock_repo_packages
@@ -86,12 +92,11 @@ def mock_pkg_names():
     # Be sure to include virtual packages since packages with stand-alone
     # tests may inherit additional tests from the virtuals they provide,
     # such as packages that implement `mpi`.
-    names = set(
+    return {
         name
         for name in repo.all_package_names(include_virtuals=True)
-        if not name.startswith("pkg-")
-    )
-    return names
+        if not name.startswith("mockpkg-")
+    }
 
 
 def split(output):
@@ -113,17 +118,17 @@ def test_mock_packages_path(mock_packages):
 
 def test_pkg_add(git, mock_pkg_git_repo):
     with working_dir(mock_pkg_git_repo):
-        mkdirp("pkg-e")
-        with open("pkg-e/package.py", "w") as f:
+        mkdirp("mockpkg-e")
+        with open("mockpkg-e/package.py", "w") as f:
             f.write(pkg_template.format(name="PkgE"))
 
-    pkg("add", "pkg-e")
+    pkg("add", "mockpkg-e")
 
     with working_dir(mock_pkg_git_repo):
         try:
-            assert "A  pkg-e/package.py" in git("status", "--short", output=str)
+            assert "A  mockpkg-e/package.py" in git("status", "--short", output=str)
         finally:
-            shutil.rmtree("pkg-e")
+            shutil.rmtree("mockpkg-e")
             # Removing a package mid-run disrupts Spack's caching
             if spack.repo.PATH.repos[0]._fast_package_checker:
                 spack.repo.PATH.repos[0]._fast_package_checker.invalidate()
@@ -138,10 +143,10 @@ def test_pkg_list(mock_pkg_git_repo, mock_pkg_names):
     assert sorted(mock_pkg_names) == sorted(out)
 
     out = split(pkg("list", "HEAD^"))
-    assert sorted(mock_pkg_names.union(["pkg-a", "pkg-b", "pkg-c"])) == sorted(out)
+    assert sorted(mock_pkg_names.union(["mockpkg-a", "mockpkg-b", "mockpkg-c"])) == sorted(out)
 
     out = split(pkg("list", "HEAD"))
-    assert sorted(mock_pkg_names.union(["pkg-a", "pkg-b", "pkg-d"])) == sorted(out)
+    assert sorted(mock_pkg_names.union(["mockpkg-a", "mockpkg-b", "mockpkg-d"])) == sorted(out)
 
     # test with three dots to make sure pkg calls `git merge-base`
     out = split(pkg("list", "HEAD^^..."))
@@ -151,25 +156,25 @@ def test_pkg_list(mock_pkg_git_repo, mock_pkg_names):
 @pytest.mark.not_on_windows("stdout format conflict")
 def test_pkg_diff(mock_pkg_git_repo, mock_pkg_names):
     out = split(pkg("diff", "HEAD^^", "HEAD^"))
-    assert out == ["HEAD^:", "pkg-a", "pkg-b", "pkg-c"]
+    assert out == ["HEAD^:", "mockpkg-a", "mockpkg-b", "mockpkg-c"]
 
     out = split(pkg("diff", "HEAD^^", "HEAD"))
-    assert out == ["HEAD:", "pkg-a", "pkg-b", "pkg-d"]
+    assert out == ["HEAD:", "mockpkg-a", "mockpkg-b", "mockpkg-d"]
 
     out = split(pkg("diff", "HEAD^", "HEAD"))
-    assert out == ["HEAD^:", "pkg-c", "HEAD:", "pkg-d"]
+    assert out == ["HEAD^:", "mockpkg-c", "HEAD:", "mockpkg-d"]
 
 
 @pytest.mark.not_on_windows("stdout format conflict")
 def test_pkg_added(mock_pkg_git_repo):
     out = split(pkg("added", "HEAD^^", "HEAD^"))
-    assert ["pkg-a", "pkg-b", "pkg-c"] == out
+    assert ["mockpkg-a", "mockpkg-b", "mockpkg-c"] == out
 
     out = split(pkg("added", "HEAD^^", "HEAD"))
-    assert ["pkg-a", "pkg-b", "pkg-d"] == out
+    assert ["mockpkg-a", "mockpkg-b", "mockpkg-d"] == out
 
     out = split(pkg("added", "HEAD^", "HEAD"))
-    assert ["pkg-d"] == out
+    assert ["mockpkg-d"] == out
 
     out = split(pkg("added", "HEAD", "HEAD"))
     assert out == []
@@ -184,7 +189,7 @@ def test_pkg_removed(mock_pkg_git_repo):
     assert out == []
 
     out = split(pkg("removed", "HEAD^", "HEAD"))
-    assert out == ["pkg-c"]
+    assert out == ["mockpkg-c"]
 
 
 @pytest.mark.not_on_windows("stdout format conflict")
@@ -196,34 +201,34 @@ def test_pkg_changed(mock_pkg_git_repo):
     assert out == []
 
     out = split(pkg("changed", "--type", "a", "HEAD^^", "HEAD^"))
-    assert out == ["pkg-a", "pkg-b", "pkg-c"]
+    assert out == ["mockpkg-a", "mockpkg-b", "mockpkg-c"]
 
     out = split(pkg("changed", "--type", "r", "HEAD^^", "HEAD^"))
     assert out == []
 
     out = split(pkg("changed", "--type", "ar", "HEAD^^", "HEAD^"))
-    assert out == ["pkg-a", "pkg-b", "pkg-c"]
+    assert out == ["mockpkg-a", "mockpkg-b", "mockpkg-c"]
 
     out = split(pkg("changed", "--type", "arc", "HEAD^^", "HEAD^"))
-    assert out == ["pkg-a", "pkg-b", "pkg-c"]
+    assert out == ["mockpkg-a", "mockpkg-b", "mockpkg-c"]
 
     out = split(pkg("changed", "HEAD^", "HEAD"))
-    assert out == ["pkg-b"]
+    assert out == ["mockpkg-b"]
 
     out = split(pkg("changed", "--type", "c", "HEAD^", "HEAD"))
-    assert out == ["pkg-b"]
+    assert out == ["mockpkg-b"]
 
     out = split(pkg("changed", "--type", "a", "HEAD^", "HEAD"))
-    assert out == ["pkg-d"]
+    assert out == ["mockpkg-d"]
 
     out = split(pkg("changed", "--type", "r", "HEAD^", "HEAD"))
-    assert out == ["pkg-c"]
+    assert out == ["mockpkg-c"]
 
     out = split(pkg("changed", "--type", "ar", "HEAD^", "HEAD"))
-    assert out == ["pkg-c", "pkg-d"]
+    assert out == ["mockpkg-c", "mockpkg-d"]
 
     out = split(pkg("changed", "--type", "arc", "HEAD^", "HEAD"))
-    assert out == ["pkg-b", "pkg-c", "pkg-d"]
+    assert out == ["mockpkg-b", "mockpkg-c", "mockpkg-d"]
 
     # invalid type argument
     with pytest.raises(spack.main.SpackCommandError):
@@ -289,7 +294,7 @@ def test_pkg_canonical_source(mock_packages):
 
 
 def test_pkg_hash(mock_packages):
-    output = pkg("hash", "a", "b").strip().split()
+    output = pkg("hash", "pkg-a", "pkg-b").strip().split()
     assert len(output) == 2 and all(len(elt) == 32 for elt in output)
 
     output = pkg("hash", "multimethod").strip().split()

lib/spack/spack/test/cmd/spec.py

@@ -58,7 +58,7 @@ def test_spec_concretizer_args(mutable_config, mutable_database, do_not_check_ru
 def test_spec_parse_dependency_variant_value():
     """Verify that we can provide multiple key=value variants to multiple separate
     packages within a spec string."""
-    output = spec("multivalue-variant fee=barbaz ^ a foobar=baz")
+    output = spec("multivalue-variant fee=barbaz ^ pkg-a foobar=baz")
 
     assert "fee=barbaz" in output
     assert "foobar=baz" in output

lib/spack/spack/test/cmd/test.py

@@ -10,10 +10,14 @@
 
 from llnl.util.filesystem import copy_tree
 
+import spack.cmd.common.arguments
 import spack.cmd.install
+import spack.cmd.test
 import spack.config
+import spack.install_test
 import spack.package_base
 import spack.paths
+import spack.spec
 import spack.store
 from spack.install_test import TestStatus
 from spack.main import SpackCommand

lib/spack/spack/test/compilers/basics.py

@@ -384,18 +384,9 @@ def test_clang_flags():
     unsupported_flag_test("cxx17_flag", "clang@3.4")
     supported_flag_test("cxx17_flag", "-std=c++1z", "clang@3.5")
     supported_flag_test("cxx17_flag", "-std=c++17", "clang@5.0")
-    unsupported_flag_test("cxx20_flag", "clang@4.0")
-    supported_flag_test("cxx20_flag", "-std=c++2a", "clang@5.0")
-    supported_flag_test("cxx20_flag", "-std=c++20", "clang@11.0")
-    unsupported_flag_test("cxx23_flag", "clang@11.0")
-    supported_flag_test("cxx23_flag", "-std=c++2b", "clang@12.0")
-    supported_flag_test("cxx23_flag", "-std=c++23", "clang@17.0")
     supported_flag_test("c99_flag", "-std=c99", "clang@3.3")
     unsupported_flag_test("c11_flag", "clang@2.0")
     supported_flag_test("c11_flag", "-std=c11", "clang@6.1.0")
-    unsupported_flag_test("c23_flag", "clang@8.0")
-    supported_flag_test("c23_flag", "-std=c2x", "clang@9.0")
-    supported_flag_test("c23_flag", "-std=c23", "clang@18.0")
     supported_flag_test("cc_pic_flag", "-fPIC", "clang@3.3")
     supported_flag_test("cxx_pic_flag", "-fPIC", "clang@3.3")
     supported_flag_test("f77_pic_flag", "-fPIC", "clang@3.3")

lib/spack/spack/test/concretize.py

@@ -24,6 +24,8 @@
 import spack.platforms
 import spack.repo
 import spack.solver.asp
+import spack.store
+import spack.util.file_cache
 import spack.util.libc
 import spack.variant as vt
 from spack.concretize import find_spec
@@ -404,7 +406,7 @@ def test_compiler_flags_from_compiler_and_dependent(self):
     def test_compiler_flags_differ_identical_compilers(self, mutable_config, clang12_with_flags):
         mutable_config.set("compilers", [clang12_with_flags])
         # Correct arch to use test compiler that has flags
-        spec = Spec("a %clang@12.2.0 platform=test os=fe target=fe")
+        spec = Spec("pkg-a %clang@12.2.0 platform=test os=fe target=fe")
 
         # Get the compiler that matches the spec (
         compiler = spack.compilers.compiler_for_spec("clang@=12.2.0", spec.architecture)
@@ -473,7 +475,7 @@ def test_architecture_deep_inheritance(self, mock_targets, compiler_factory):
                 assert s.architecture.target == spec.architecture.target
 
     def test_compiler_flags_from_user_are_grouped(self):
-        spec = Spec('a%gcc cflags="-O -foo-flag foo-val" platform=test')
+        spec = Spec('pkg-a%gcc cflags="-O -foo-flag foo-val" platform=test')
         spec.concretize()
         cflags = spec.compiler_flags["cflags"]
         assert any(x == "-foo-flag foo-val" for x in cflags)
@@ -581,20 +583,20 @@ def test_concretize_propagate_multivalue_variant(self):
         spec = Spec("multivalue-variant foo==baz,fee")
         spec.concretize()
 
-        assert spec.satisfies("^a foo=baz,fee")
-        assert spec.satisfies("^b foo=baz,fee")
-        assert not spec.satisfies("^a foo=bar")
-        assert not spec.satisfies("^b foo=bar")
+        assert spec.satisfies("^pkg-a foo=baz,fee")
+        assert spec.satisfies("^pkg-b foo=baz,fee")
+        assert not spec.satisfies("^pkg-a foo=bar")
+        assert not spec.satisfies("^pkg-b foo=bar")
 
     def test_no_matching_compiler_specs(self, mock_low_high_config):
         # only relevant when not building compilers as needed
         with spack.concretize.enable_compiler_existence_check():
-            s = Spec("a %gcc@=0.0.0")
+            s = Spec("pkg-a %gcc@=0.0.0")
             with pytest.raises(spack.concretize.UnavailableCompilerVersionError):
                 s.concretize()
 
     def test_no_compilers_for_arch(self):
-        s = Spec("a arch=linux-rhel0-x86_64")
+        s = Spec("pkg-a arch=linux-rhel0-x86_64")
         with pytest.raises(spack.error.SpackError):
             s.concretize()
 
@@ -803,7 +805,7 @@ def test_regression_issue_7941(self):
         # The string representation of a spec containing
         # an explicit multi-valued variant and a dependency
         # might be parsed differently than the originating spec
-        s = Spec("a foobar=bar ^b")
+        s = Spec("pkg-a foobar=bar ^pkg-b")
         t = Spec(str(s))
 
         s.concretize()
@@ -1183,14 +1185,14 @@ def test_conditional_provides_or_depends_on(self):
         [
             # Check that True is treated correctly and attaches test deps
             # to all nodes in the DAG
-            ("a", True, ["a"], []),
-            ("a foobar=bar", True, ["a", "b"], []),
+            ("pkg-a", True, ["pkg-a"], []),
+            ("pkg-a foobar=bar", True, ["pkg-a", "pkg-b"], []),
             # Check that a list of names activates the dependency only for
             # packages in that list
-            ("a foobar=bar", ["a"], ["a"], ["b"]),
-            ("a foobar=bar", ["b"], ["b"], ["a"]),
+            ("pkg-a foobar=bar", ["pkg-a"], ["pkg-a"], ["pkg-b"]),
+            ("pkg-a foobar=bar", ["pkg-b"], ["pkg-b"], ["pkg-a"]),
             # Check that False disregard test dependencies
-            ("a foobar=bar", False, [], ["a", "b"]),
+            ("pkg-a foobar=bar", False, [], ["pkg-a", "pkg-b"]),
         ],
     )
     def test_activating_test_dependencies(self, spec_str, tests_arg, with_dep, without_dep):
@@ -1249,7 +1251,7 @@ def test_custom_compiler_version(self, mutable_config, compiler_factory, monkeyp
             "compilers", [compiler_factory(spec="gcc@10foo", operating_system="redhat6")]
         )
         monkeypatch.setattr(spack.compiler.Compiler, "real_version", "10.2.1")
-        s = Spec("a %gcc@10foo os=redhat6").concretized()
+        s = Spec("pkg-a %gcc@10foo os=redhat6").concretized()
         assert "%gcc@10foo" in s
 
     def test_all_patches_applied(self):
@@ -1393,10 +1395,10 @@ def test_no_reuse_when_variant_condition_does_not_hold(self, mutable_database, m
     @pytest.mark.only_clingo("Use case not supported by the original concretizer")
     def test_reuse_with_flags(self, mutable_database, mutable_config):
         spack.config.set("concretizer:reuse", True)
-        spec = Spec("a cflags=-g cxxflags=-g").concretized()
+        spec = Spec("pkg-a cflags=-g cxxflags=-g").concretized()
         spack.store.STORE.db.add(spec, None)
 
-        testspec = Spec("a cflags=-g")
+        testspec = Spec("pkg-a cflags=-g")
         testspec.concretize()
         assert testspec == spec
 
@@ -1739,49 +1741,49 @@ def test_reuse_with_unknown_namespace_dont_raise(
         self, temporary_store, mock_custom_repository
     ):
         with spack.repo.use_repositories(mock_custom_repository, override=False):
-            s = Spec("c").concretized()
+            s = Spec("pkg-c").concretized()
             assert s.namespace != "builtin.mock"
             s.package.do_install(fake=True, explicit=True)
 
         with spack.config.override("concretizer:reuse", True):
-            s = Spec("c").concretized()
+            s = Spec("pkg-c").concretized()
         assert s.namespace == "builtin.mock"
 
     @pytest.mark.regression("28259")
     def test_reuse_with_unknown_package_dont_raise(self, tmpdir, temporary_store, monkeypatch):
         builder = spack.repo.MockRepositoryBuilder(tmpdir.mkdir("mock.repo"), namespace="myrepo")
-        builder.add_package("c")
+        builder.add_package("pkg-c")
         with spack.repo.use_repositories(builder.root, override=False):
-            s = Spec("c").concretized()
+            s = Spec("pkg-c").concretized()
             assert s.namespace == "myrepo"
             s.package.do_install(fake=True, explicit=True)
 
-        del sys.modules["spack.pkg.myrepo.c"]
+        del sys.modules["spack.pkg.myrepo.pkg-c"]
         del sys.modules["spack.pkg.myrepo"]
-        builder.remove("c")
+        builder.remove("pkg-c")
         with spack.repo.use_repositories(builder.root, override=False) as repos:
             # TODO (INJECT CONFIGURATION): unclear why the cache needs to be invalidated explicitly
             repos.repos[0]._pkg_checker.invalidate()
             with spack.config.override("concretizer:reuse", True):
-                s = Spec("c").concretized()
+                s = Spec("pkg-c").concretized()
             assert s.namespace == "builtin.mock"
 
     @pytest.mark.parametrize(
-        "specs,expected",
+        "specs,expected,libc_offset",
         [
-            (["libelf", "libelf@0.8.10"], 1),
-            (["libdwarf%gcc", "libelf%clang"], 2),
-            (["libdwarf%gcc", "libdwarf%clang"], 3),
-            (["libdwarf^libelf@0.8.12", "libdwarf^libelf@0.8.13"], 4),
-            (["hdf5", "zmpi"], 3),
-            (["hdf5", "mpich"], 2),
-            (["hdf5^zmpi", "mpich"], 4),
-            (["mpi", "zmpi"], 2),
-            (["mpi", "mpich"], 1),
+            (["libelf", "libelf@0.8.10"], 1, 1),
+            (["libdwarf%gcc", "libelf%clang"], 2, 1),
+            (["libdwarf%gcc", "libdwarf%clang"], 3, 2),
+            (["libdwarf^libelf@0.8.12", "libdwarf^libelf@0.8.13"], 4, 1),
+            (["hdf5", "zmpi"], 3, 1),
+            (["hdf5", "mpich"], 2, 1),
+            (["hdf5^zmpi", "mpich"], 4, 1),
+            (["mpi", "zmpi"], 2, 1),
+            (["mpi", "mpich"], 1, 1),
         ],
     )
     @pytest.mark.only_clingo("Original concretizer cannot concretize in rounds")
-    def test_best_effort_coconcretize(self, specs, expected):
+    def test_best_effort_coconcretize(self, specs, expected, libc_offset):
         specs = [Spec(s) for s in specs]
         solver = spack.solver.asp.Solver()
         solver.reuse = False
@@ -1790,7 +1792,9 @@ def test_best_effort_coconcretize(self, specs, expected):
             for s in result.specs:
                 concrete_specs.update(s.traverse())
 
-        libc_offset = 1 if spack.solver.asp.using_libc_compatibility() else 0
+        if not spack.solver.asp.using_libc_compatibility():
+            libc_offset = 0
+
         assert len(concrete_specs) == expected + libc_offset
 
     @pytest.mark.parametrize(
@@ -1892,20 +1896,20 @@ def test_misleading_error_message_on_version(self, mutable_database):
     @pytest.mark.only_clingo("Use case not supported by the original concretizer")
     def test_version_weight_and_provenance(self):
         """Test package preferences during coconcretization."""
-        reusable_specs = [Spec(spec_str).concretized() for spec_str in ("b@0.9", "b@1.0")]
-        root_spec = Spec("a foobar=bar")
+        reusable_specs = [Spec(spec_str).concretized() for spec_str in ("pkg-b@0.9", "pkg-b@1.0")]
+        root_spec = Spec("pkg-a foobar=bar")
 
         with spack.config.override("concretizer:reuse", True):
             solver = spack.solver.asp.Solver()
             setup = spack.solver.asp.SpackSolverSetup()
             result, _, _ = solver.driver.solve(setup, [root_spec], reuse=reusable_specs)
-            # The result here should have a single spec to build ('a')
-            # and it should be using b@1.0 with a version badness of 2
+            # The result here should have a single spec to build ('pkg-a')
+            # and it should be using pkg-b@1.0 with a version badness of 2
             # The provenance is:
-            # version_declared("b","1.0",0,"package_py").
-            # version_declared("b","0.9",1,"package_py").
-            # version_declared("b","1.0",2,"installed").
-            # version_declared("b","0.9",3,"installed").
+            # version_declared("pkg-b","1.0",0,"package_py").
+            # version_declared("pkg-b","0.9",1,"package_py").
+            # version_declared("pkg-b","1.0",2,"installed").
+            # version_declared("pkg-b","0.9",3,"installed").
             #
             # Depending on the target, it may also use gnuconfig
             result_spec = result.specs[0]
@@ -1919,11 +1923,11 @@ def test_version_weight_and_provenance(self):
 
             for criterion in criteria:
                 assert criterion in result.criteria, criterion
-            assert result_spec.satisfies("^b@1.0")
+            assert result_spec.satisfies("^pkg-b@1.0")
 
     @pytest.mark.only_clingo("Use case not supported by the original concretizer")
     def test_reuse_succeeds_with_config_compatible_os(self):
-        root_spec = Spec("b")
+        root_spec = Spec("pkg-b")
         s = root_spec.concretized()
         other_os = s.copy()
         mock_os = "ubuntu2204"
@@ -2187,7 +2191,7 @@ def test_external_python_extension_find_unified_python(self):
         "specs",
         [
             ["mpileaks^ callpath ^dyninst@8.1.1:8 ^mpich2@1.3:1"],
-            ["multivalue-variant ^a@2:2"],
+            ["multivalue-variant ^pkg-a@2:2"],
             ["v1-consumer ^conditional-provider@1:1 +disable-v1"],
         ],
     )
@@ -2226,9 +2230,9 @@ def test_unsolved_specs_raises_error(self, monkeypatch, mock_packages, config):
     def test_clear_error_when_unknown_compiler_requested(self, mock_packages, config):
         """Tests that the solver can report a case where the compiler cannot be set"""
         with pytest.raises(
-            spack.error.UnsatisfiableSpecError, match="Cannot set the required compiler: a%foo"
+            spack.error.UnsatisfiableSpecError, match="Cannot set the required compiler: pkg-a%foo"
         ):
-            Spec("a %foo").concretized()
+            Spec("pkg-a %foo").concretized()
 
     @pytest.mark.regression("36339")
     def test_compiler_match_constraints_when_selected(self):
@@ -2264,7 +2268,7 @@ def test_compiler_match_constraints_when_selected(self):
             },
         ]
         spack.config.set("compilers", compiler_configuration)
-        s = Spec("a %gcc@:11").concretized()
+        s = Spec("pkg-a %gcc@:11").concretized()
         assert s.compiler.version == ver("=11.1.0"), s
 
     @pytest.mark.regression("36339")
@@ -2285,7 +2289,7 @@ def test_compiler_with_custom_non_numeric_version(self, mock_executable):
             }
         ]
         spack.config.set("compilers", compiler_configuration)
-        s = Spec("a %gcc@foo").concretized()
+        s = Spec("pkg-a %gcc@foo").concretized()
         assert s.compiler.version == ver("=foo")
 
     @pytest.mark.regression("36628")
@@ -2311,7 +2315,7 @@ def test_concretization_with_compilers_supporting_target_any(self):
         ]
 
         with spack.config.override("compilers", compiler_configuration):
-            s = spack.spec.Spec("a").concretized()
+            s = Spec("pkg-a").concretized()
         assert s.satisfies("%gcc@12.1.0")
 
     @pytest.mark.parametrize("spec_str", ["mpileaks", "mpileaks ^mpich"])
@@ -2346,7 +2350,7 @@ def test_dont_define_new_version_from_input_if_checksum_required(self, working_e
         with pytest.raises(spack.error.UnsatisfiableSpecError):
             # normally spack concretizes to @=3.0 if it's not defined in package.py, except
             # when checksums are required
-            Spec("a@=3.0").concretized()
+            Spec("pkg-a@=3.0").concretized()
 
     @pytest.mark.regression("39570")
     @pytest.mark.db
@@ -2446,7 +2450,7 @@ def _default_libc(self):
             spack.util.libc, "libc_from_current_python_process", lambda: Spec("glibc@=2.28")
         )
         mutable_config.set("config:install_missing_compilers", True)
-        s = Spec("a %gcc@=13.2.0").concretized()
+        s = Spec("pkg-a %gcc@=13.2.0").concretized()
         assert s.satisfies("%gcc@13.2.0")
 
     @pytest.mark.regression("43267")
@@ -2546,6 +2550,79 @@ def test_include_specs_from_externals_and_libcs(
 
         assert result["deprecated-versions"].satisfies("@1.0.0")
 
+    @pytest.mark.regression("44085")
+    @pytest.mark.only_clingo("Use case not supported by the original concretizer")
+    def test_can_reuse_concrete_externals_for_dependents(self, mutable_config, tmp_path):
+        """Test that external specs that are in the DB can be reused. This means they are
+        preferred to concretizing another external from packages.yaml
+        """
+        packages_yaml = {
+            "externaltool": {"externals": [{"spec": "externaltool@2.0", "prefix": "/fake/path"}]}
+        }
+        mutable_config.set("packages", packages_yaml)
+        # Concretize with gcc@9 to get a suboptimal spec, since we have gcc@10 available
+        external_spec = Spec("externaltool@2 %gcc@9").concretized()
+        assert external_spec.external
+
+        root_specs = [Spec("sombrero")]
+        with spack.config.override("concretizer:reuse", True):
+            solver = spack.solver.asp.Solver()
+            setup = spack.solver.asp.SpackSolverSetup()
+            result, _, _ = solver.driver.solve(setup, root_specs, reuse=[external_spec])
+
+        assert len(result.specs) == 1
+        sombrero = result.specs[0]
+        assert sombrero["externaltool"].dag_hash() == external_spec.dag_hash()
+
+    @pytest.mark.regression("45321")
+    @pytest.mark.parametrize(
+        "corrupted_str",
+        [
+            "cmake@3.4.3 foo=bar",  # cmake has no variant "foo"
+            "mvdefaults@1.0 foo=a,d",  # variant "foo" has no value "d"
+            "cmake %gcc",  # spec has no version
+        ],
+    )
+    def test_corrupted_external_does_not_halt_concretization(self, corrupted_str, mutable_config):
+        """Tests that having a wrong variant in an external spec doesn't stop concretization"""
+        corrupted_spec = Spec(corrupted_str)
+        packages_yaml = {
+            f"{corrupted_spec.name}": {
+                "externals": [{"spec": corrupted_str, "prefix": "/dev/null"}]
+            }
+        }
+        mutable_config.set("packages", packages_yaml)
+        # Assert we don't raise due to the corrupted external entry above
+        s = Spec("pkg-a").concretized()
+        assert s.concrete
+
+    @pytest.mark.regression("44828")
+    @pytest.mark.not_on_windows("Tests use linux paths")
+    def test_correct_external_is_selected_from_packages_yaml(self, mutable_config):
+        """Tests that when filtering external specs, the correct external is selected to
+        reconstruct the prefix, and other external attributes.
+        """
+        packages_yaml = {
+            "cmake": {
+                "externals": [
+                    {"spec": "cmake@3.23.1 %gcc", "prefix": "/tmp/prefix1"},
+                    {"spec": "cmake@3.23.1 %clang", "prefix": "/tmp/prefix2"},
+                ]
+            }
+        }
+        concretizer_yaml = {
+            "reuse": {"roots": True, "from": [{"type": "external", "exclude": ["%gcc"]}]}
+        }
+        mutable_config.set("packages", packages_yaml)
+        mutable_config.set("concretizer", concretizer_yaml)
+
+        s = Spec("cmake").concretized()
+
+        # Check that we got the properties from the right external
+        assert s.external
+        assert s.satisfies("%clang")
+        assert s.prefix == "/tmp/prefix2"
+
 
 @pytest.fixture()
 def duplicates_test_repository():
@@ -2747,7 +2824,9 @@ def test_drop_moving_targets(v_str, v_opts, checksummed):
 class TestConcreteSpecsByHash:
     """Tests the container of concrete specs"""
 
-    @pytest.mark.parametrize("input_specs", [["a"], ["a foobar=bar", "b"], ["a foobar=baz", "b"]])
+    @pytest.mark.parametrize(
+        "input_specs", [["pkg-a"], ["pkg-a foobar=bar", "pkg-b"], ["pkg-a foobar=baz", "pkg-b"]]
+    )
     def test_adding_specs(self, input_specs, default_mock_concretization):
         """Tests that concrete specs in the container are equivalent, but stored as different
         objects in memory.

lib/spack/spack/test/concretize_compiler_runtimes.py

@@ -9,6 +9,7 @@
 
 import archspec.cpu
 
+import spack.config
 import spack.paths
 import spack.repo
 import spack.solver.asp
@@ -47,8 +48,8 @@ def enable_runtimes():
 
 
 def test_correct_gcc_runtime_is_injected_as_dependency(runtime_repo):
-    s = spack.spec.Spec("a%gcc@10.2.1 ^b%gcc@9.4.0").concretized()
-    a, b = s["a"], s["b"]
+    s = spack.spec.Spec("pkg-a%gcc@10.2.1 ^pkg-b%gcc@9.4.0").concretized()
+    a, b = s["pkg-a"], s["pkg-b"]
 
     # Both a and b should depend on the same gcc-runtime directly
     assert a.dependencies("gcc-runtime") == b.dependencies("gcc-runtime")
@@ -61,16 +62,16 @@ def test_correct_gcc_runtime_is_injected_as_dependency(runtime_repo):
 def test_external_nodes_do_not_have_runtimes(runtime_repo, mutable_config, tmp_path):
     """Tests that external nodes don't have runtime dependencies."""
 
-    packages_yaml = {"b": {"externals": [{"spec": "b@1.0", "prefix": f"{str(tmp_path)}"}]}}
+    packages_yaml = {"pkg-b": {"externals": [{"spec": "pkg-b@1.0", "prefix": f"{str(tmp_path)}"}]}}
     spack.config.set("packages", packages_yaml)
 
-    s = spack.spec.Spec("a%gcc@10.2.1").concretized()
+    s = spack.spec.Spec("pkg-a%gcc@10.2.1").concretized()
 
-    a, b = s["a"], s["b"]
+    a, b = s["pkg-a"], s["pkg-b"]
 
     # Since b is an external, it doesn't depend on gcc-runtime
     assert a.dependencies("gcc-runtime")
-    assert a.dependencies("b")
+    assert a.dependencies("pkg-b")
     assert not b.dependencies("gcc-runtime")
 
 
@@ -78,23 +79,36 @@ def test_external_nodes_do_not_have_runtimes(runtime_repo, mutable_config, tmp_p
     "root_str,reused_str,expected,nruntime",
     [
         # The reused runtime is older than we need, thus we'll add a more recent one for a
-        ("a%gcc@10.2.1", "b%gcc@9.4.0", {"a": "gcc-runtime@10.2.1", "b": "gcc-runtime@9.4.0"}, 2),
-        # The root is compiled with an older compiler, thus we'll reuse the runtime from b
-        ("a%gcc@9.4.0", "b%gcc@10.2.1", {"a": "gcc-runtime@10.2.1", "b": "gcc-runtime@10.2.1"}, 1),
+        (
+            "pkg-a%gcc@10.2.1",
+            "pkg-b%gcc@9.4.0",
+            {"pkg-a": "gcc-runtime@10.2.1", "pkg-b": "gcc-runtime@9.4.0"},
+            2,
+        ),
+        # The root is compiled with an older compiler, thus we'll NOT reuse the runtime from b
+        (
+            "pkg-a%gcc@9.4.0",
+            "pkg-b%gcc@10.2.1",
+            {"pkg-a": "gcc-runtime@9.4.0", "pkg-b": "gcc-runtime@9.4.0"},
+            1,
+        ),
         # Same as before, but tests that we can reuse from a more generic target
         pytest.param(
-            "a%gcc@9.4.0",
-            "b%gcc@10.2.1 target=x86_64",
-            {"a": "gcc-runtime@10.2.1 target=x86_64", "b": "gcc-runtime@10.2.1 target=x86_64"},
+            "pkg-a%gcc@9.4.0",
+            "pkg-b%gcc@10.2.1 target=x86_64",
+            {"pkg-a": "gcc-runtime@9.4.0", "pkg-b": "gcc-runtime@9.4.0"},
             1,
             marks=pytest.mark.skipif(
                 str(archspec.cpu.host().family) != "x86_64", reason="test data is x86_64 specific"
             ),
         ),
         pytest.param(
-            "a%gcc@10.2.1",
-            "b%gcc@9.4.0 target=x86_64",
-            {"a": "gcc-runtime@10.2.1 target=x86_64", "b": "gcc-runtime@9.4.0 target=x86_64"},
+            "pkg-a%gcc@10.2.1",
+            "pkg-b%gcc@9.4.0 target=x86_64",
+            {
+                "pkg-a": "gcc-runtime@10.2.1 target=x86_64",
+                "pkg-b": "gcc-runtime@9.4.0 target=x86_64",
+            },
             2,
             marks=pytest.mark.skipif(
                 str(archspec.cpu.host().family) != "x86_64", reason="test data is x86_64 specific"
@@ -102,17 +116,19 @@ def test_external_nodes_do_not_have_runtimes(runtime_repo, mutable_config, tmp_p
         ),
     ],
 )
+@pytest.mark.regression("44444")
 def test_reusing_specs_with_gcc_runtime(root_str, reused_str, expected, nruntime, runtime_repo):
     """Tests that we can reuse specs with a "gcc-runtime" leaf node. In particular, checks
     that the semantic for gcc-runtimes versions accounts for reused packages too.
+
+    Reusable runtime versions should be lower, or equal, to that of parent nodes.
     """
     root, reused_spec = _concretize_with_reuse(root_str=root_str, reused_str=reused_str)
 
-    assert f"{expected['b']}" in reused_spec
     runtime_a = root.dependencies("gcc-runtime")[0]
-    assert runtime_a.satisfies(expected["a"])
-    runtime_b = root["b"].dependencies("gcc-runtime")[0]
-    assert runtime_b.satisfies(expected["b"])
+    assert runtime_a.satisfies(expected["pkg-a"])
+    runtime_b = root["pkg-b"].dependencies("gcc-runtime")[0]
+    assert runtime_b.satisfies(expected["pkg-b"])
 
     runtimes = [x for x in root.traverse() if x.name == "gcc-runtime"]
     assert len(runtimes) == nruntime
@@ -123,8 +139,7 @@ def test_reusing_specs_with_gcc_runtime(root_str, reused_str, expected, nruntime
     [
         # Ensure that, whether we have multiple runtimes in the DAG or not,
         # we always link only the latest version
-        ("a%gcc@10.2.1", "b%gcc@9.4.0", ["gcc-runtime@10.2.1"], ["gcc-runtime@9.4.0"]),
-        ("a%gcc@9.4.0", "b%gcc@10.2.1", ["gcc-runtime@10.2.1"], ["gcc-runtime@9.4.0"]),
+        ("pkg-a%gcc@10.2.1", "pkg-b%gcc@9.4.0", ["gcc-runtime@10.2.1"], ["gcc-runtime@9.4.0"])
     ],
 )
 def test_views_can_handle_duplicate_runtime_nodes(

lib/spack/spack/test/concretize_preferences.py

@@ -512,5 +512,5 @@ def test_default_preference_variant_different_type_does_not_error(self):
         packages.yaml doesn't fail with an error.
         """
         with spack.config.override("packages:all", {"variants": "+foo"}):
-            s = Spec("a").concretized()
+            s = Spec("pkg-a").concretized()
             assert s.satisfies("foo=bar")

lib/spack/spack/test/concretize_requirements.py

@@ -103,23 +103,6 @@ def test_repo(_create_test_repo, monkeypatch, mock_stage):
         yield mock_repo_path
 
 
-class MakeStage:
-    def __init__(self, stage):
-        self.stage = stage
-
-    def __call__(self, *args, **kwargs):
-        return self.stage
-
-
-@pytest.fixture
-def fake_installs(monkeypatch, tmpdir):
-    stage_path = str(tmpdir.ensure("fake-stage", dir=True))
-    universal_unused_stage = spack.stage.DIYStage(stage_path)
-    monkeypatch.setattr(
-        spack.build_systems.generic.Package, "_make_stage", MakeStage(universal_unused_stage)
-    )
-
-
 def test_one_package_multiple_reqs(concretize_scope, test_repo):
     conf_str = """\
 packages:
@@ -514,7 +497,7 @@ def test_oneof_ordering(concretize_scope, test_repo):
     assert s2.satisfies("@2.5")
 
 
-def test_reuse_oneof(concretize_scope, _create_test_repo, mutable_database, fake_installs):
+def test_reuse_oneof(concretize_scope, _create_test_repo, mutable_database, mock_fetch):
     conf_str = """\
 packages:
   y:
@@ -944,9 +927,9 @@ def test_default_requirements_semantic(packages_yaml, concretize_scope, mock_pac
         Spec("zlib ~shared").concretized()
 
     # A spec without the shared variant still concretize
-    s = Spec("a").concretized()
-    assert not s.satisfies("a +shared")
-    assert not s.satisfies("a ~shared")
+    s = Spec("pkg-a").concretized()
+    assert not s.satisfies("pkg-a +shared")
+    assert not s.satisfies("pkg-a ~shared")
 
 
 @pytest.mark.parametrize(
@@ -1176,3 +1159,46 @@ def test_forward_multi_valued_variant_using_requires(
 
     for constraint in not_expected:
         assert not s.satisfies(constraint)
+
+
+def test_strong_preferences_higher_priority_than_reuse(concretize_scope, mock_packages):
+    """Tests that strong preferences have a higher priority than reusing specs."""
+    reused_spec = Spec("adios2~bzip2").concretized()
+    reuse_nodes = list(reused_spec.traverse())
+    root_specs = [Spec("ascent+adios2")]
+
+    # Check that without further configuration adios2 is reused
+    with spack.config.override("concretizer:reuse", True):
+        solver = spack.solver.asp.Solver()
+        setup = spack.solver.asp.SpackSolverSetup()
+        result, _, _ = solver.driver.solve(setup, root_specs, reuse=reuse_nodes)
+        ascent = result.specs[0]
+    assert ascent["adios2"].dag_hash() == reused_spec.dag_hash(), ascent
+
+    # If we stick a preference, adios2 is not reused
+    update_packages_config(
+        """
+    packages:
+      adios2:
+        prefer:
+        - "+bzip2"
+"""
+    )
+    with spack.config.override("concretizer:reuse", True):
+        solver = spack.solver.asp.Solver()
+        setup = spack.solver.asp.SpackSolverSetup()
+        result, _, _ = solver.driver.solve(setup, root_specs, reuse=reuse_nodes)
+        ascent = result.specs[0]
+
+    assert ascent["adios2"].dag_hash() != reused_spec.dag_hash()
+    assert ascent["adios2"].satisfies("+bzip2")
+
+    # A preference is still preference, so we can override from input
+    with spack.config.override("concretizer:reuse", True):
+        solver = spack.solver.asp.Solver()
+        setup = spack.solver.asp.SpackSolverSetup()
+        result, _, _ = solver.driver.solve(
+            setup, [Spec("ascent+adios2 ^adios2~bzip2")], reuse=reuse_nodes
+        )
+        ascent = result.specs[0]
+    assert ascent["adios2"].dag_hash() == reused_spec.dag_hash(), ascent

lib/spack/spack/test/config.py

@@ -18,6 +18,7 @@
 import spack.config
 import spack.directory_layout
 import spack.environment as ev
+import spack.fetch_strategy
 import spack.main
 import spack.package_base
 import spack.paths
@@ -1211,13 +1212,13 @@ def test_license_dir_config(mutable_config, mock_packages):
     expected_dir = spack.paths.default_license_dir
     assert spack.config.get("config:license_dir") == expected_dir
     assert spack.package_base.PackageBase.global_license_dir == expected_dir
-    assert spack.repo.PATH.get_pkg_class("a").global_license_dir == expected_dir
+    assert spack.repo.PATH.get_pkg_class("pkg-a").global_license_dir == expected_dir
 
     rel_path = os.path.join(os.path.sep, "foo", "bar", "baz")
     spack.config.set("config:license_dir", rel_path)
     assert spack.config.get("config:license_dir") == rel_path
     assert spack.package_base.PackageBase.global_license_dir == rel_path
-    assert spack.repo.PATH.get_pkg_class("a").global_license_dir == rel_path
+    assert spack.repo.PATH.get_pkg_class("pkg-a").global_license_dir == rel_path
 
 
 @pytest.mark.regression("22547")
@@ -1492,26 +1493,3 @@ def test_config_path_dsl(path, it_should_work, expected_parsed):
     else:
         with pytest.raises(ValueError):
             spack.config.ConfigPath._validate(path)
-
-
-def test_compiler_parsing_errors(tmpdir):
-    content = """\
-packages:
-  gcc:
-    externals:
-    - spec: gcc@8.5.0 languages='c,c++,fortran'
-      prefix: /usr
-      extra_attributes:
-        compilers:
-          c: /usr/bin/gcc
-          cxx: /usr/bin/g++
-          fortran: /usr/bin/gfortran
-"""
-
-    testscope = join_path(tmpdir.strpath, "packages.yaml")
-    with open(testscope, "w") as f:
-        f.write(content)
-
-    with spack.config.use_configuration(tmpdir.strpath):
-        compilers = spack.compilers.get_compiler_config_from_packages(spack.config.CONFIG)
-        assert spack.spec.Spec(compilers[0]["compiler"]["spec"]).satisfies("gcc@8.5.0")