Issue 11004: Fix edge case for deque.count().
diff --git a/Lib/test/test_deque.py b/Lib/test/test_deque.py
index 1d3f726..a0d30f1 100644
--- a/Lib/test/test_deque.py
+++ b/Lib/test/test_deque.py
@@ -137,6 +137,15 @@
m.d = d
self.assertRaises(RuntimeError, d.count, 3)
+ # test issue11004
+ # block advance failed after rotation aligned elements on right side of block
+ d = deque([None]*16)
+ for i in range(len(d)):
+ d.rotate(-1)
+ d.rotate(1)
+ self.assertEqual(d.count(1), 0)
+ self.assertEqual(d.count(None), 16)
+
def test_comparisons(self):
d = deque('xabc'); d.popleft()
for e in [d, deque('abc'), deque('ab'), deque(), list(d)]:
diff --git a/Misc/NEWS b/Misc/NEWS
index 42ce636..f244c23 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -19,6 +19,8 @@
non-Python managed memory while it is being modified by another thread.
Patch by Matt Bandy.
+- Issue #11004: Repaired edge case in deque.count().
+
- Issue #8278: On Windows and with a NTFS filesystem, os.stat() and os.utime()
can now handle dates after 2038.
diff --git a/Modules/_collectionsmodule.c b/Modules/_collectionsmodule.c
index c140e97..faa2577 100644
--- a/Modules/_collectionsmodule.c
+++ b/Modules/_collectionsmodule.c
@@ -485,7 +485,8 @@
/* Advance left block/index pair */
leftindex++;
if (leftindex == BLOCKLEN) {
- assert (leftblock->rightlink != NULL);
+ if (leftblock->rightlink == NULL)
+ break;
leftblock = leftblock->rightlink;
leftindex = 0;
}
@@ -493,7 +494,8 @@
/* Step backwards with the right block/index pair */
rightindex--;
if (rightindex == -1) {
- assert (rightblock->leftlink != NULL);
+ if (rightblock->leftlink == NULL)
+ break;
rightblock = rightblock->leftlink;
rightindex = BLOCKLEN - 1;
}
@@ -509,7 +511,7 @@
{
block *leftblock = deque->leftblock;
Py_ssize_t leftindex = deque->leftindex;
- Py_ssize_t n = (deque->len);
+ Py_ssize_t n = deque->len;
Py_ssize_t i;
Py_ssize_t count = 0;
PyObject *item;
@@ -533,7 +535,8 @@
/* Advance left block/index pair */
leftindex++;
if (leftindex == BLOCKLEN) {
- assert (leftblock->rightlink != NULL);
+ if (leftblock->rightlink == NULL) /* can occur when i==n-1 */
+ break;
leftblock = leftblock->rightlink;
leftindex = 0;
}