Close #14199: _PyType_Lookup() and super_getattro() keep a strong reference to
the type MRO to avoid a crash if the MRO is changed during the lookup.
diff --git a/Lib/test/test_descr.py b/Lib/test/test_descr.py
index 45fd05d..f405fbb 100644
--- a/Lib/test/test_descr.py
+++ b/Lib/test/test_descr.py
@@ -4582,10 +4582,38 @@
type.mro(tuple)
+class MiscTests(unittest.TestCase):
+ def test_type_lookup_mro_reference(self):
+ # Issue #14199: _PyType_Lookup() has to keep a strong reference to
+ # the type MRO because it may be modified during the lookup, if
+ # __bases__ is set during the lookup for example.
+ class MyKey(object):
+ def __hash__(self):
+ return hash('mykey')
+
+ def __eq__(self, other):
+ X.__bases__ = (Base2,)
+
+ class Base(object):
+ mykey = 'from Base'
+ mykey2 = 'from Base'
+
+ class Base2(object):
+ mykey = 'from Base2'
+ mykey2 = 'from Base2'
+
+ X = type('X', (Base,), {MyKey(): 5})
+ # mykey is read from Base
+ self.assertEqual(X.mykey, 'from Base')
+ # mykey2 is read from Base2 because MyKey.__eq__ has set __bases__
+ self.assertEqual(X.mykey2, 'from Base2')
+
+
def test_main():
# Run all local test cases, with PTypesLongInitTest first.
support.run_unittest(PTypesLongInitTest, OperatorsTest,
- ClassPropertiesAndMethods, DictProxyTests)
+ ClassPropertiesAndMethods, DictProxyTests,
+ MiscTests)
if __name__ == "__main__":
test_main()