https://github.com/python/cpython/commit/b215552a32666d38db5e85e1a6da91374610dd73
commit: b215552a32666d38db5e85e1a6da91374610dd73
branch: main
author: Samartha <[email protected]>
committer: JelleZijlstra <[email protected]>
date: 2026-09-17T02:48:25Z
summary:
gh-157621: Clear weakrefs for ParamSpec attributes (#157622)
files:
A Misc/NEWS.d/next/Library/2026-09-16-14-04-38.gh-issue-157621.R6v2S8.rst
M Lib/test/test_typing.py
M Objects/typevarobject.c
diff --git a/Lib/test/test_typing.py b/Lib/test/test_typing.py
index f35f864dce21e86..b0d468b34092b25 100644
--- a/Lib/test/test_typing.py
+++ b/Lib/test/test_typing.py
@@ -10299,6 +10299,17 @@ def test_args_kwargs(self):
self.assertEqual(repr(P.args), "P.args")
self.assertEqual(repr(P.kwargs), "P.kwargs")
+ def test_args_kwargs_weakrefs(self):
+ P = ParamSpec('P')
+ for attr_name in ('args', 'kwargs'):
+ with self.subTest(attr_name=attr_name):
+ callback_fired = []
+ attr = getattr(P, attr_name)
+ ref = weakref.ref(attr, lambda _: callback_fired.append(True))
+ del attr
+ self.assertEqual(callback_fired, [True])
+ self.assertIsNone(ref())
+
def test_stringized(self):
P = ParamSpec('P')
class C(Generic[P]):
diff --git
a/Misc/NEWS.d/next/Library/2026-09-16-14-04-38.gh-issue-157621.R6v2S8.rst
b/Misc/NEWS.d/next/Library/2026-09-16-14-04-38.gh-issue-157621.R6v2S8.rst
new file mode 100644
index 000000000000000..b8342da0faebb91
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2026-09-16-14-04-38.gh-issue-157621.R6v2S8.rst
@@ -0,0 +1,2 @@
+Fix a crash when a weak-reference callback is attached to a
+:class:`typing.ParamSpecArgs` or :class:`typing.ParamSpecKwargs` instance.
diff --git a/Objects/typevarobject.c b/Objects/typevarobject.c
index 53c350838969616..eed1457cbb426d9 100644
--- a/Objects/typevarobject.c
+++ b/Objects/typevarobject.c
@@ -958,6 +958,7 @@ paramspecattr_dealloc(PyObject *self)
_PyObject_GC_UNTRACK(self);
Py_XDECREF(psa->__origin__);
+ PyObject_ClearWeakRefs(self);
Py_TYPE(self)->tp_free(self);
Py_DECREF(tp);
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