From: Jeong, YunWon <69878+youknowone@users.noreply.github.com>
Date: Sat, 5 Jul 2025 14:24:33 +0000 (+0900)
Subject: gh-136047: Allow typing._allow_reckless_class_checks to check `_py_abc` (#136115)
X-Git-Tag: v3.15.0a1~1085
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=887e5c8646dfc6dd3d64b482c5310a414ac9162b;p=thirdparty%2FPython%2Fcpython.git

gh-136047: Allow typing._allow_reckless_class_checks to check `_py_abc` (#136115)
---

diff --git a/Lib/typing.py b/Lib/typing.py
index 4ebf0eb92f58..27105838a0a0 100644
--- a/Lib/typing.py
+++ b/Lib/typing.py
@@ -1866,7 +1866,9 @@ def _allow_reckless_class_checks(depth=2):
     The abc and functools modules indiscriminately call isinstance() and
     issubclass() on the whole MRO of a user class, which may contain protocols.
     """
-    return _caller(depth) in {'abc', 'functools', None}
+    # gh-136047: When `_abc` module is not available, `_py_abc` is required to
+    # allow `_py_abc.ABCMeta` fallback.
+    return _caller(depth) in {'abc', '_py_abc', 'functools', None}
 
 
 _PROTO_ALLOWLIST = {
diff --git a/Misc/NEWS.d/next/Library/2025-07-05-06-59-46.gh-issue-136047.qWvycf.rst b/Misc/NEWS.d/next/Library/2025-07-05-06-59-46.gh-issue-136047.qWvycf.rst
new file mode 100644
index 000000000000..1a381860914b
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2025-07-05-06-59-46.gh-issue-136047.qWvycf.rst
@@ -0,0 +1,2 @@
+Fix issues with :mod:`typing` when the C implementation of :mod:`abc` is not
+available.