[2.7] closes bpo-31608: Fix a crash in methods of a subclass of _collections.deque with a bad __new__(). (GH-9179)
diff --git a/Lib/test/test_deque.py b/Lib/test/test_deque.py
index c81064d..e6307ab 100644
--- a/Lib/test/test_deque.py
+++ b/Lib/test/test_deque.py
@@ -659,6 +659,21 @@
d1 == d2 # not clear if this is supposed to be True or False,
# but it used to give a SystemError
+ @test_support.cpython_only
+ def test_bug_31608(self):
+ # The interpreter used to crash in specific cases where a deque
+ # subclass returned a non-deque.
+ class X(deque):
+ pass
+ d = X()
+ def bad___new__(cls, *args, **kwargs):
+ return [42]
+ X.__new__ = bad___new__
+ with self.assertRaises(TypeError):
+ d * 42 # shouldn't crash
+ with self.assertRaises(TypeError):
+ d + deque([1, 2, 3]) # shouldn't crash
+
class SubclassWithKwargs(deque):
def __init__(self, newarg=1):