commit 53b977127fe8192f8bdf6a400de81086e128e936
author Benjamin Peterson <benjamin@python.org> Mon Apr 23 11:50:47 2012 -0400
committer Benjamin Peterson <benjamin@python.org> Mon Apr 23 11:50:47 2012 -0400
tree 1df86df7bdd10a7da1be122f260ab710d0dea130
parent 99e6f87586cd11d0d881891851c831a8d7ebb902

don't make shared keys with dict subclasses

Objects/dictobject.c

diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index 2e45c8d..2afbbae 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -3686,7 +3686,7 @@
             res = PyDict_SetItem(dict, key, value);
             if (cached != ((PyDictObject *)dict)->ma_keys) {
                 /* Either update tp->ht_cached_keys or delete it */
-                if (cached->dk_refcnt == 1) {
+                if (cached->dk_refcnt == 1 && PyDict_CheckExact(dict)) {
                     CACHED_KEYS(tp) = make_keys_shared(dict);
                     if (CACHED_KEYS(tp) == NULL)
                         return -1;