Originally posted by @brandtbucher in #115874 (comment):

I also think I found an unrelated refleak while chasing this down:

diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index fe3b7b87c8..181d032328 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -6549,6 +6549,7 @@ reduce_newobj(PyObject *obj)
     }
     else {
         /* args == NULL */
+        Py_DECREF(copyreg);
         Py_DECREF(kwargs);
         PyErr_BadInternalCall();
         return NULL;

Linked PRs

• gh-116296: Fix refleak in reduce_newobj() corner case #116297
• [3.12] gh-116296: Fix refleak in reduce_newobj() corner case (GH-116297) #116299
• [3.11] gh-116296: Fix refleak in reduce_newobj() corner case (GH-116297) #116300