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)