Create 'localize_package_path' function to convert stdlib to local ve…

…rsions of PackagePath.

importlib_metadata/__init__.py

@@ -35,8 +35,9 @@
     install,
     localize_dist,
     localize_metadata,
+    localize_package_path,
 )
-from ._functools import apply, method_cache, pass_none
+from ._functools import apply, compose, method_cache, pass_none
 from ._itertools import always_iterable, bucket, unique_everseen
 from ._meta import PackageMetadata, SimplePath
 from .compat import py39, py311
@@ -529,6 +530,7 @@ def entry_points(self) -> EntryPoints:
         return EntryPoints._from_text_for(self.read_text('entry_points.txt'), self)
 
     @property
+    @apply(pass_none(compose(list, functools.partial(map, localize_package_path))))
     def files(self) -> Optional[List[PackagePath]]:
         """Files in this distribution.
 

importlib_metadata/_compat.py

@@ -91,3 +91,13 @@ def localize_metadata(
     if isinstance(input, importlib_metadata._adapters.Message):
         return input
     return importlib_metadata._adapters.Message(input)
+
+
+def localize_package_path(
+    input: importlib_metadata.PackagePath | importlib.metadata.PackagePath,
+) -> importlib_metadata.PackagePath:
+    if isinstance(input, importlib_metadata.PackagePath):
+        return input
+    replacement = importlib_metadata.PackagePath(input)
+    vars(replacement).update(vars(input))
+    return replacement