From: Raymond Hettinger <python@rcn.com>
Date: Sat, 2 Feb 2013 20:26:37 +0000 (-0800)
Subject: Issue 16398: One more assertion for good measure.
X-Git-Tag: v3.4.0a1~1466
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=3a9ae7fd984ea9e5c9d3e22c87c61c02c03dd1c9;p=python

Issue 16398: One more assertion for good measure.
---

diff --git a/Modules/_collectionsmodule.c b/Modules/_collectionsmodule.c
index 17b1ad68e1..d0a47b8992 100644
--- a/Modules/_collectionsmodule.c
+++ b/Modules/_collectionsmodule.c
@@ -484,6 +484,8 @@ _deque_rotate(dequeobject *deque, Py_ssize_t n)
         if (m > BLOCKLEN - 1 - deque->rightindex)
             m = BLOCKLEN - 1 - deque->rightindex;
         assert (m > 0);
+        assert (deque->leftblock != deque->rightblock ||
+                deque->leftindex + m < deque->rightindex + 1);
         memcpy(&deque->rightblock->data[deque->rightindex + 1],
                &deque->leftblock->data[deque->leftindex],
                m * sizeof(PyObject *));