Restore 'origin' to IDistribution.

Consumers should be able to rely on it, and the exemption now keeps a
provider on Python 3.11 or 3.12, whose stdlib has no origin to inherit,
from being warned about its absence.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: jaraco

importlib_metadata/_meta.py

@@ -136,6 +136,9 @@ def files(self) -> list[IPackagePath] | None: ...  # pragma: no cover
     @property
     def requires(self) -> list[str] | None: ...  # pragma: no cover
 
+    @property
+    def origin(self) -> Any: ...  # pragma: no cover
+
     @classmethod
     def discover(
         cls, *, context: Any | None = None, **kwargs: Any

tests/compat/test_protocols.py

@@ -5,10 +5,12 @@
 
 import importlib.metadata as stdlib
 import pathlib
+import sys
 import tempfile
 import unittest
 
 from importlib_metadata import IDistribution, IPackagePath, PackageMetadata
+from importlib_metadata.compat import py312
 
 
 class StdlibProtocolTests(unittest.TestCase):
@@ -23,6 +25,12 @@ def setUp(self):
         )
         self.dist = stdlib.PathDistribution(dist_info)
 
+    def test_stdlib_distribution_conforms(self):
+        assert py312.conforms(self.dist, IDistribution)
+
+    @unittest.skipIf(
+        sys.version_info < (3, 13), "stdlib Distribution.origin added in Python 3.13"
+    )
     def test_stdlib_distribution_matches_protocol(self):
         assert isinstance(self.dist, IDistribution)