From: Raymond Hettinger <python@rcn.com>
Date: Wed, 30 Sep 2015 05:45:05 +0000 (-0700)
Subject: Add an early-out for deque_clear()
X-Git-Tag: v3.6.0a1~1371
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=38031143fbab6267fe464a1cb39eeb5c68de38f4;p=python

Add an early-out for deque_clear()
---

diff --git a/Modules/_collectionsmodule.c b/Modules/_collectionsmodule.c
index 5db7aed377..d9df5749e1 100644
--- a/Modules/_collectionsmodule.c
+++ b/Modules/_collectionsmodule.c
@@ -595,6 +595,9 @@ deque_clear(dequeobject *deque)
     Py_ssize_t n;
     PyObject *item;
 
+    if (Py_SIZE(deque) == 0)
+        return;
+
     /* During the process of clearing a deque, decrefs can cause the
        deque to mutate.  To avoid fatal confusion, we have to make the
        deque empty before clearing the blocks and never refer to