bpo-39590: make deque.__contains__ and deque.count hold strong references (GH-18421)
diff --git a/Lib/test/test_deque.py b/Lib/test/test_deque.py
index 51b66b7..c0f7138 100644
--- a/Lib/test/test_deque.py
+++ b/Lib/test/test_deque.py
@@ -183,6 +183,18 @@
with self.assertRaises(RuntimeError):
n in d
+ def test_contains_count_stop_crashes(self):
+ class A:
+ def __eq__(self, other):
+ d.clear()
+ return NotImplemented
+ d = deque([A(), A()])
+ with self.assertRaises(RuntimeError):
+ _ = 3 in d
+ d = deque([A(), A()])
+ with self.assertRaises(RuntimeError):
+ _ = d.count(3)
+
def test_extend(self):
d = deque('a')
self.assertRaises(TypeError, d.extend, 1)
diff --git a/Misc/NEWS.d/next/Library/2020-02-09-05-51-05.bpo-39590.rf98GU.rst b/Misc/NEWS.d/next/Library/2020-02-09-05-51-05.bpo-39590.rf98GU.rst
new file mode 100644
index 0000000..6862502
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2020-02-09-05-51-05.bpo-39590.rf98GU.rst
@@ -0,0 +1 @@
+Collections.deque now holds strong references during deque.__contains__ and deque.count, fixing crashes.
\ No newline at end of file
diff --git a/Modules/_collectionsmodule.c b/Modules/_collectionsmodule.c
index 1003060..25e4c96 100644
--- a/Modules/_collectionsmodule.c
+++ b/Modules/_collectionsmodule.c
@@ -965,7 +965,9 @@
while (--n >= 0) {
CHECK_NOT_END(b);
item = b->data[index];
+ Py_INCREF(item);
cmp = PyObject_RichCompareBool(item, v, Py_EQ);
+ Py_DECREF(item);
if (cmp < 0)
return NULL;
count += cmp;
@@ -1002,7 +1004,9 @@
while (--n >= 0) {
CHECK_NOT_END(b);
item = b->data[index];
+ Py_INCREF(item);
cmp = PyObject_RichCompareBool(item, v, Py_EQ);
+ Py_DECREF(item);
if (cmp) {
return cmp;
}