Neaten-up a bit add add missing size change check.
diff --git a/Modules/_heapqmodule.c b/Modules/_heapqmodule.c
index 7f3ce79..b3e4753 100644
--- a/Modules/_heapqmodule.c
+++ b/Modules/_heapqmodule.c
@@ -12,9 +12,8 @@
_siftdown(PyListObject *heap, Py_ssize_t startpos, Py_ssize_t pos)
{
PyObject *newitem, *parent;
+ Py_ssize_t parentpos, size;
int cmp;
- Py_ssize_t parentpos;
- Py_ssize_t size;
assert(PyList_Check(heap));
size = PyList_GET_SIZE(heap);
@@ -26,7 +25,7 @@
/* Follow the path to the root, moving parents down until finding
a place newitem fits. */
newitem = PyList_GET_ITEM(heap, pos);
- while (pos > startpos){
+ while (pos > startpos) {
parentpos = (pos - 1) >> 1;
parent = PyList_GET_ITEM(heap, parentpos);
cmp = PyObject_RichCompareBool(newitem, parent, Py_LT);
@@ -355,11 +354,12 @@
_siftdownmax(PyListObject *heap, Py_ssize_t startpos, Py_ssize_t pos)
{
PyObject *newitem, *parent;
+ Py_ssize_t parentpos, size;
int cmp;
- Py_ssize_t parentpos;
assert(PyList_Check(heap));
- if (pos >= PyList_GET_SIZE(heap)) {
+ size = PyList_GET_SIZE(heap);
+ if (pos >= size) {
PyErr_SetString(PyExc_IndexError, "index out of range");
return -1;
}
@@ -367,12 +367,17 @@
/* Follow the path to the root, moving parents down until finding
a place newitem fits. */
newitem = PyList_GET_ITEM(heap, pos);
- while (pos > startpos){
+ while (pos > startpos) {
parentpos = (pos - 1) >> 1;
parent = PyList_GET_ITEM(heap, parentpos);
cmp = PyObject_RichCompareBool(parent, newitem, Py_LT);
if (cmp == -1)
return -1;
+ if (size != PyList_GET_SIZE(heap)) {
+ PyErr_SetString(PyExc_RuntimeError,
+ "list changed size during iteration");
+ return -1;
+ }
if (cmp == 0)
break;
parent = PyList_GET_ITEM(heap, parentpos);