Hoist distrubution factory methods to base class

2 files changed, 24 insertions, 9 deletions

diff --git a/src/pip/_internal/metadata/base.py b/src/pip/_internal/metadata/base.py
index 7586dfc46..2d6bb1cc8 100644
--- a/src/pip/_internal/metadata/base.py
+++ b/src/pip/_internal/metadata/base.py
@@ -96,6 +96,28 @@ def _convert_installed_files_path(
 
 
 class BaseDistribution(Protocol):
+    @classmethod
+    def from_directory(cls, directory: str) -> "BaseDistribution":
+        """Load the distribution from a metadata directory.
+
+        :param directory: Path to a metadata directory, e.g. ``.dist-info``.
+        """
+        raise NotImplementedError()
+
+    @classmethod
+    def from_wheel(cls, wheel: "Wheel", name: str) -> "BaseDistribution":
+        """Load the distribution from a given wheel.
+
+        :param wheel: A concrete wheel definition.
+        :param name: File name of the wheel.
+
+        :raises InvalidWheel: Whenever loading of the wheel causes a
+            :py:exc:`zipfile.BadZipFile` exception to be thrown.
+        :raises UnsupportedWheel: If the wheel is a valid zip, but malformed
+            internally.
+        """
+        raise NotImplementedError()
+
     def __repr__(self) -> str:
         return f"{self.raw_name} {self.version} ({self.location})"
 
diff --git a/src/pip/_internal/metadata/pkg_resources.py b/src/pip/_internal/metadata/pkg_resources.py
index 0e56f98e2..667fbb936 100644
--- a/src/pip/_internal/metadata/pkg_resources.py
+++ b/src/pip/_internal/metadata/pkg_resources.py
@@ -73,7 +73,7 @@ class Distribution(BaseDistribution):
         self._dist = dist
 
     @classmethod
-    def from_directory(cls, directory: str) -> "Distribution":
+    def from_directory(cls, directory: str) -> BaseDistribution:
         dist_dir = directory.rstrip(os.sep)
 
         # Build a PathMetadata object, from path to metadata. :wink:
@@ -93,14 +93,7 @@ class Distribution(BaseDistribution):
         return cls(dist)
 
     @classmethod
-    def from_wheel(cls, wheel: Wheel, name: str) -> "Distribution":
-        """Load the distribution from a given wheel.
-
-        :raises InvalidWheel: Whenever loading of the wheel causes a
-            :py:exc:`zipfile.BadZipFile` exception to be thrown.
-        :raises UnsupportedWheel: If the wheel is a valid zip, but malformed
-            internally.
-        """
+    def from_wheel(cls, wheel: Wheel, name: str) -> BaseDistribution:
         try:
             with wheel.as_zipfile() as zf:
                 info_dir, _ = parse_wheel(zf, name)