python.py/r.py: fix type issues with classproperty/constant (#50059)

lib/spack/docs/conf.py

@@ -225,8 +225,10 @@ def setup(sphinx):
     ("py:class", "llnl.util.lang.T"),
     ("py:class", "llnl.util.lang.KT"),
     ("py:class", "llnl.util.lang.VT"),
+    ("py:class", "llnl.util.lang.ClassPropertyType"),
     ("py:obj", "llnl.util.lang.KT"),
     ("py:obj", "llnl.util.lang.VT"),
+    ("py:obj", "llnl.util.lang.ClassPropertyType"),
 ]
 
 # The reST default role (used for this markup: `text`) to use for all documents.

lib/spack/llnl/util/lang.py

@@ -15,7 +15,19 @@
 import typing
 import warnings
 from datetime import datetime, timedelta
-from typing import Callable, Dict, Iterable, List, Mapping, Optional, Tuple, TypeVar
+from typing import (
+    Any,
+    Callable,
+    Dict,
+    Generic,
+    Iterable,
+    List,
+    Mapping,
+    Optional,
+    Tuple,
+    TypeVar,
+    Union,
+)
 
 # Ignore emacs backups when listing modules
 ignore_modules = r"^\.#|~$"
@@ -1047,19 +1059,28 @@ def __exit__(self, exc_type, exc_value, tb):
         return True
 
 
-class classproperty:
+ClassPropertyType = TypeVar("ClassPropertyType")
+
+
+class classproperty(Generic[ClassPropertyType]):
     """Non-data descriptor to evaluate a class-level property. The function that performs
-    the evaluation is injected at creation time and take an instance (could be None) and
-    an owner (i.e. the class that originated the instance)
+    the evaluation is injected at creation time and takes an owner (i.e., the class that
+    originated the instance).
     """
 
-    def __init__(self, callback):
+    def __init__(self, callback: Callable[[Any], ClassPropertyType]) -> None:
         self.callback = callback
 
-    def __get__(self, instance, owner):
+    def __get__(self, instance, owner) -> ClassPropertyType:
         return self.callback(owner)
 
 
+#: A type alias that represents either a classproperty descriptor or a constant value of the same
+#: type. This allows derived classes to override a computed class-level property with a constant
+#: value while retaining type compatibility.
+ClassProperty = Union[ClassPropertyType, classproperty[ClassPropertyType]]
+
+
 class DeprecatedProperty:
     """Data descriptor to error or warn when a deprecated property is accessed.
 

lib/spack/spack/build_systems/python.py

@@ -13,9 +13,9 @@
 import archspec
 
 import llnl.util.filesystem as fs
-import llnl.util.lang as lang
 import llnl.util.tty as tty
 from llnl.util.filesystem import HeaderList, LibraryList, join_path
+from llnl.util.lang import ClassProperty, classproperty, match_predicate
 
 import spack.builder
 import spack.config
@@ -139,7 +139,7 @@ def view_file_conflicts(self, view, merge_map):
             ext_map = view.extensions_layout.extension_map(self.extendee_spec)
             namespaces = set(x.package.py_namespace for x in ext_map.values())
             namespace_re = r"site-packages/{0}/__init__.py".format(self.py_namespace)
-            find_namespace = lang.match_predicate(namespace_re)
+            find_namespace = match_predicate(namespace_re)
             if self.py_namespace in namespaces:
                 conflicts = list(x for x in conflicts if not find_namespace(x))
 
@@ -206,7 +206,7 @@ def remove_files_from_view(self, view, merge_map):
                 spec.package.py_namespace for name, spec in ext_map.items() if name != self.name
             )
             if self.py_namespace in remaining_namespaces:
-                namespace_init = lang.match_predicate(
+                namespace_init = match_predicate(
                     r"site-packages/{0}/__init__.py".format(self.py_namespace)
                 )
                 ignore_namespace = True
@@ -324,6 +324,27 @@ def get_external_python_for_prefix(self):
         raise StopIteration("No external python could be detected for %s to depend on" % self.spec)
 
 
+def _homepage(cls: "PythonPackage") -> Optional[str]:
+    """Get the homepage from PyPI if available."""
+    if cls.pypi:
+        name = cls.pypi.split("/")[0]
+        return f"https://pypi.org/project/{name}/"
+    return None
+
+
+def _url(cls: "PythonPackage") -> Optional[str]:
+    if cls.pypi:
+        return f"https://files.pythonhosted.org/packages/source/{cls.pypi[0]}/{cls.pypi}"
+    return None
+
+
+def _list_url(cls: "PythonPackage") -> Optional[str]:
+    if cls.pypi:
+        name = cls.pypi.split("/")[0]
+        return f"https://pypi.org/simple/{name}/"
+    return None
+
+
 class PythonPackage(PythonExtension):
     """Specialized class for packages that are built using pip."""
 
@@ -351,25 +372,9 @@ class PythonPackage(PythonExtension):
 
     py_namespace: Optional[str] = None
 
-    @lang.classproperty
-    def homepage(cls) -> Optional[str]:  # type: ignore[override]
-        if cls.pypi:
-            name = cls.pypi.split("/")[0]
-            return f"https://pypi.org/project/{name}/"
-        return None
-
-    @lang.classproperty
-    def url(cls) -> Optional[str]:
-        if cls.pypi:
-            return f"https://files.pythonhosted.org/packages/source/{cls.pypi[0]}/{cls.pypi}"
-        return None
-
-    @lang.classproperty
-    def list_url(cls) -> Optional[str]:  # type: ignore[override]
-        if cls.pypi:
-            name = cls.pypi.split("/")[0]
-            return f"https://pypi.org/simple/{name}/"
-        return None
+    homepage: ClassProperty[Optional[str]] = classproperty(_homepage)
+    url: ClassProperty[Optional[str]] = classproperty(_url)
+    list_url: ClassProperty[Optional[str]] = classproperty(_list_url)
 
     @property
     def python_spec(self) -> Spec:

lib/spack/spack/build_systems/r.py

@@ -3,8 +3,8 @@
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 from typing import Optional, Tuple
 
-import llnl.util.lang as lang
 from llnl.util.filesystem import mkdirp
+from llnl.util.lang import ClassProperty, classproperty
 
 from spack.directives import extends
 
@@ -54,6 +54,32 @@ def install(self, pkg, spec, prefix):
         pkg.module.R(*args)
 
 
+def _homepage(cls: "RPackage") -> Optional[str]:
+    if cls.cran:
+        return f"https://cloud.r-project.org/package={cls.cran}"
+    elif cls.bioc:
+        return f"https://bioconductor.org/packages/{cls.bioc}"
+    return None
+
+
+def _url(cls: "RPackage") -> Optional[str]:
+    if cls.cran:
+        return f"https://cloud.r-project.org/src/contrib/{cls.cran}_{str(list(cls.versions)[0])}.tar.gz"
+    return None
+
+
+def _list_url(cls: "RPackage") -> Optional[str]:
+    if cls.cran:
+        return f"https://cloud.r-project.org/src/contrib/Archive/{cls.cran}/"
+    return None
+
+
+def _git(cls: "RPackage") -> Optional[str]:
+    if cls.bioc:
+        return f"https://git.bioconductor.org/packages/{cls.bioc}"
+    return None
+
+
 class RPackage(Package):
     """Specialized class for packages that are built using R.
 
@@ -77,24 +103,7 @@ class RPackage(Package):
 
     extends("r")
 
-    @lang.classproperty
-    def homepage(cls):
-        if cls.cran:
-            return f"https://cloud.r-project.org/package={cls.cran}"
-        elif cls.bioc:
-            return f"https://bioconductor.org/packages/{cls.bioc}"
-
-    @lang.classproperty
-    def url(cls):
-        if cls.cran:
-            return f"https://cloud.r-project.org/src/contrib/{cls.cran}_{str(list(cls.versions)[0])}.tar.gz"
-
-    @lang.classproperty
-    def list_url(cls):
-        if cls.cran:
-            return f"https://cloud.r-project.org/src/contrib/Archive/{cls.cran}/"
-
-    @lang.classproperty
-    def git(cls):
-        if cls.bioc:
-            return f"https://git.bioconductor.org/packages/{cls.bioc}"
+    homepage: ClassProperty[Optional[str]] = classproperty(_homepage)
+    url: ClassProperty[Optional[str]] = classproperty(_url)
+    list_url: ClassProperty[Optional[str]] = classproperty(_list_url)
+    git: ClassProperty[Optional[str]] = classproperty(_git)

lib/spack/spack/build_systems/racket.py

@@ -5,8 +5,8 @@
 from typing import Optional, Tuple
 
 import llnl.util.filesystem as fs
-import llnl.util.lang as lang
 import llnl.util.tty as tty
+from llnl.util.lang import ClassProperty, classproperty
 
 import spack.builder
 import spack.spec
@@ -19,6 +19,12 @@
 from spack.util.executable import Executable, ProcessError
 
 
+def _homepage(cls: "RacketPackage") -> Optional[str]:
+    if cls.racket_name:
+        return f"https://pkgs.racket-lang.org/package/{cls.racket_name}"
+    return None
+
+
 class RacketPackage(PackageBase):
     """Specialized class for packages that are built using Racket's
     `raco pkg install` and `raco setup` commands.
@@ -37,13 +43,7 @@ class RacketPackage(PackageBase):
     extends("racket", when="build_system=racket")
 
     racket_name: Optional[str] = None
-    parallel = True
-
-    @lang.classproperty
-    def homepage(cls):
-        if cls.racket_name:
-            return "https://pkgs.racket-lang.org/package/{0}".format(cls.racket_name)
-        return None
+    homepage: ClassProperty[Optional[str]] = classproperty(_homepage)
 
 
 @spack.builder.builder("racket")

lib/spack/spack/package_base.py

@@ -28,7 +28,7 @@
 
 import llnl.util.filesystem as fsys
 import llnl.util.tty as tty
-from llnl.util.lang import classproperty, memoized
+from llnl.util.lang import ClassProperty, classproperty, memoized
 
 import spack.config
 import spack.dependency
@@ -701,10 +701,10 @@ class PackageBase(WindowsRPath, PackageViewMixin, metaclass=PackageMeta):
     _verbose = None
 
     #: Package homepage where users can find more information about the package
-    homepage: Optional[str] = None
+    homepage: ClassProperty[Optional[str]] = None
 
     #: Default list URL (place to find available versions)
-    list_url: Optional[str] = None
+    list_url: ClassProperty[Optional[str]] = None
 
     #: Link depth to which list_url should be searched for new versions
     list_depth = 0