[3.10] gh-99130: Apply bugfixes from importlib_metadata 4.11.4. (#99132)

Lib/importlib/metadata/__init__.py

@@ -17,7 +17,7 @@
 from . import _adapters, _meta
 from ._meta import PackageMetadata
 from ._collections import FreezableDefaultDict, Pair
-from ._functools import method_cache
+from ._functools import method_cache, pass_none
 from ._itertools import unique_everseen
 from ._meta import PackageMetadata, SimplePath
 
@@ -938,13 +938,25 @@ def _normalized_name(self):
         normalized name from the file system path.
         """
         stem = os.path.basename(str(self._path))
-        return self._name_from_stem(stem) or super()._normalized_name
+        return (
+            pass_none(Prepared.normalize)(self._name_from_stem(stem))
+            or super()._normalized_name
+        )
 
-    def _name_from_stem(self, stem):
-        name, ext = os.path.splitext(stem)
+    @staticmethod
+    def _name_from_stem(stem):
+        """
+        >>> PathDistribution._name_from_stem('foo-3.0.egg-info')
+        'foo'
+        >>> PathDistribution._name_from_stem('CherryPy-3.0.dist-info')
+        'CherryPy'
+        >>> PathDistribution._name_from_stem('face.egg-info')
+        'face'
+        """
+        filename, ext = os.path.splitext(stem)
         if ext not in ('.dist-info', '.egg-info'):
             return
-        name, sep, rest = stem.partition('-')
+        name, sep, rest = filename.partition('-')
         return name
 
 

Lib/importlib/metadata/_functools.py

@@ -83,3 +83,22 @@ def wrapper(self, *args, **kwargs):
     wrapper.cache_clear = lambda: None
 
     return wrapper
+
+
+# From jaraco.functools 3.3
+def pass_none(func):
+    """
+    Wrap func so it's not called if its first param is None
+
+    >>> print_text = pass_none(print)
+    >>> print_text('text')
+    text
+    >>> print_text(None)
+    """
+
+    @functools.wraps(func)
+    def wrapper(param, *args, **kwargs):
+        if param is not None:
+            return func(param, *args, **kwargs)
+
+    return wrapper

Lib/test/test_importlib/test_metadata_api.py

@@ -89,13 +89,15 @@ def test_entry_points_distribution(self):
             self.assertIn(ep.dist.name, ('distinfo-pkg', 'egginfo-pkg'))
             self.assertEqual(ep.dist.version, "1.0.0")
 
-    def test_entry_points_unique_packages(self):
-        # Entry points should only be exposed for the first package
-        # on sys.path with a given name.
+    def test_entry_points_unique_packages_normalized(self):
+        """
+        Entry points should only be exposed for the first package
+        on sys.path with a given name (even when normalized).
+        """
         alt_site_dir = self.fixtures.enter_context(fixtures.tempdir())
         self.fixtures.enter_context(self.add_sys_path(alt_site_dir))
         alt_pkg = {
-            "distinfo_pkg-1.1.0.dist-info": {
+            "DistInfo_pkg-1.1.0.dist-info": {
                 "METADATA": """
                 Name: distinfo-pkg
                 Version: 1.1.0

Misc/NEWS.d/next/Library/2022-11-05-11-42-15.gh-issue-99130.91MMXu.rst

@@ -0,0 +1,7 @@
+Apply bugfixes from `importlib_metadata 4.11.4
+<https://importlib-metadata.readthedocs.io/en/latest/history.html#v4-11-4>`_,
+namely: In ``PathDistribution._name_from_stem``, avoid including parts of
+the extension in the result. In ``PathDistribution._normalized_name``,
+ensure names loaded from the stem of the filename are also normalized,
+ensuring duplicate entry points by packages varying only by non-normalized
+name are hidden.