meta: add Path protocol for PathDistribution

This is needed to properly annotate code that uses PathDistribution,
otherwise I need to keep redefining the protocol in my code.

Signed-off-by: Filipe Laíns <[email protected]>

Author: FFY00

importlib_metadata/__init__.py

@@ -15,7 +15,7 @@
 import collections
 
 from . import _adapters, _meta
-from ._meta import PackageMetadata
+from ._meta import PackageMetadata, Path
 from ._collections import FreezableDefaultDict, Pair
 from ._compat import (
     NullFinder,
@@ -783,7 +783,7 @@ def invalidate_caches(cls):
 
 
 class PathDistribution(Distribution):
-    def __init__(self, path):
+    def __init__(self, path: Path):
         """Construct a distribution from a path to the metadata directory.
 
         :param path: A pathlib.Path or similar object supporting

importlib_metadata/_meta.py

@@ -28,3 +28,17 @@ def json(self) -> Dict[str, Union[str, List[str]]]:
         """
         A JSON-compatible form of the metadata.
         """
+
+
+class Path(Protocol):
+    def joinpath(self) -> 'Path':
+        ...  # pragma: no cover
+
+    def __div__(self) -> 'Path':
+        ...  # pragma: no cover
+
+    def parent(self) -> 'Path':
+        ...  # pragma: no cover
+
+    def read_text(self) -> str:
+        ...  # pragma: no cover