commit b9db9e152f3325b075e59ef4fdecfd0b9ec4746c
author Raymond Hettinger <python@rcn.com> Mon May 11 19:58:56 2015 -0700
committer Raymond Hettinger <python@rcn.com> Mon May 11 19:58:56 2015 -0700
tree 94395cbc2ae10300d1aba7c735abec04e7756850
parent 1af2bf75a2f816eaaf8353eaab8b6dcfee0064c0

Defend against a mutation during comparison

Modules/_heapqmodule.c

diff --git a/Modules/_heapqmodule.c b/Modules/_heapqmodule.c
index 38bcdbe..04845f1 100644
--- a/Modules/_heapqmodule.c
+++ b/Modules/_heapqmodule.c
@@ -224,6 +224,11 @@
         return item;
     }
 
+    if (PyList_GET_SIZE(heap) == 0) {
+        PyErr_SetString(PyExc_IndexError, "index out of range");
+        return NULL;
+    }
+
     returnitem = PyList_GET_ITEM(heap, 0);
     Py_INCREF(item);
     PyList_SET_ITEM(heap, 0, item);