Prevent vendored importlib_metadata from loading distributions from older importlib_metadata. Fixes #3102.

1 files changed, 23 insertions, 0 deletions

diff --git a/setuptools/_importlib.py b/setuptools/_importlib.py
index c529ccd3..c1ac137e 100644
--- a/setuptools/_importlib.py
+++ b/setuptools/_importlib.py
@@ -1,8 +1,31 @@
 import sys
 
 
+def disable_importlib_metadata_finder(metadata):
+    """
+    Ensure importlib_metadata doesn't provide older, incompatible
+    Distributions.
+
+    Workaround for #3102.
+    """
+    try:
+        import importlib_metadata
+    except ImportError:
+        return
+    if importlib_metadata is metadata:
+        return
+    to_remove = [
+        ob
+        for ob in sys.meta_path
+        if isinstance(ob, importlib_metadata.MetadataPathFinder)
+    ]
+    for item in to_remove:
+        sys.meta_path.remove(item)
+
+
 if sys.version_info < (3, 10):
     from setuptools.extern import importlib_metadata as metadata
+    disable_importlib_metadata_finder(metadata)
 else:
     import importlib.metadata as metadata  # noqa: F401