From 5f52d20a93908196f74271db8437cc1ba7e1e262 Mon Sep 17 00:00:00 2001
From: "Jason R. Coombs" <jaraco@jaraco.com>
Date: Thu, 14 Mar 2024 17:59:00 -0400
Subject: [PATCH] gh-116811: Ensure MetadataPathFinder.invalidate_caches is
 reachable when delegated through PathFinder. (#116812)

* Make MetadataPathFinder a proper classmethod.

* In PathFinder.invalidate_caches, also invoke MetadataPathFinder.invalidate_caches.

* Add blurb
---
 Lib/importlib/_bootstrap_external.py                           | 3 +++
 Lib/importlib/metadata/__init__.py                             | 1 +
 .../Library/2024-03-14-10-01-23.gh-issue-116811._h5iKP.rst     | 2 ++
 3 files changed, 6 insertions(+)
 create mode 100644 Misc/NEWS.d/next/Library/2024-03-14-10-01-23.gh-issue-116811._h5iKP.rst

diff --git a/Lib/importlib/_bootstrap_external.py b/Lib/importlib/_bootstrap_external.py
index 46ddceed07b..b26be8583d0 100644
--- a/Lib/importlib/_bootstrap_external.py
+++ b/Lib/importlib/_bootstrap_external.py
@@ -1470,6 +1470,9 @@ class PathFinder:
         # https://bugs.python.org/issue45703
         _NamespacePath._epoch += 1
 
+        from importlib.metadata import MetadataPathFinder
+        MetadataPathFinder.invalidate_caches()
+
     @staticmethod
     def _path_hooks(path):
         """Search sys.path_hooks for a finder for 'path'."""
diff --git a/Lib/importlib/metadata/__init__.py b/Lib/importlib/metadata/__init__.py
index c612fbefee2..41c2a4a6088 100644
--- a/Lib/importlib/metadata/__init__.py
+++ b/Lib/importlib/metadata/__init__.py
@@ -797,6 +797,7 @@ class MetadataPathFinder(DistributionFinder):
             path.search(prepared) for path in map(FastPath, paths)
         )
 
+    @classmethod
     def invalidate_caches(cls) -> None:
         FastPath.__new__.cache_clear()
 
diff --git a/Misc/NEWS.d/next/Library/2024-03-14-10-01-23.gh-issue-116811._h5iKP.rst b/Misc/NEWS.d/next/Library/2024-03-14-10-01-23.gh-issue-116811._h5iKP.rst
new file mode 100644
index 00000000000..00168632429
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2024-03-14-10-01-23.gh-issue-116811._h5iKP.rst
@@ -0,0 +1,2 @@
+In ``PathFinder.invalidate_caches``, delegate to
+``MetadataPathFinder.invalidate_caches``.