commit 659030c7d56a329c1aa559678f2df15e306215e4
author Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com> Sat Jul 24 02:45:13 2021 -0700
committer GitHub <noreply@github.com> Sat Jul 24 11:45:13 2021 +0200
tree 2472aacf20968fc67df0fea1efb6d6c9d67b144e
parent d15949a845a6db66675bca7105ad508ba9e79639

bpo-44720: Don't crash when calling weakref.proxy(not_an_iterator).__next__ (GH-27316) (GH-27324)

(cherry picked from commit 5370f0a82aaa4ba617070d5c71d2b18236096ac0)

Co-authored-by: Dennis Sweeney <36520290+sweeneyde@users.noreply.github.com>

Objects/weakrefobject.c

diff --git a/Objects/weakrefobject.c b/Objects/weakrefobject.c
index c36d239..bb56c7d 100644
--- a/Objects/weakrefobject.c
+++ b/Objects/weakrefobject.c
@@ -657,6 +657,12 @@ proxy_iternext(PyWeakReference *proxy)
         return NULL;
 
     PyObject *obj = PyWeakref_GET_OBJECT(proxy);
+    if (!PyIter_Check(obj)) {
+        PyErr_Format(PyExc_TypeError,
+            "Weakref proxy referenced a non-iterator '%.200s' object",
+            Py_TYPE(obj)->tp_name);
+        return NULL;
+    }
     Py_INCREF(obj);
     PyObject* res = PyIter_Next(obj);
     Py_DECREF(obj);