closes bpo-31608: Fix a crash in methods of a subclass of _collections.deque with a bad __new__(). (GH-3788)
(cherry picked from commit 24bd50bdcc97d65130c07d6cd26085fd06c3e972)
Co-authored-by: Oren Milman <orenmn@gmail.com>
diff --git a/Lib/test/test_deque.py b/Lib/test/test_deque.py
index e895c3c..9211360 100644
--- a/Lib/test/test_deque.py
+++ b/Lib/test/test_deque.py
@@ -892,6 +892,21 @@
d1 == d2 # not clear if this is supposed to be True or False,
# but it used to give a SystemError
+ @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):