diff --git a/Lib/test/test_iter.py b/Lib/test/test_iter.py index e4243033057..4d971835cb1 100644 --- a/Lib/test/test_iter.py +++ b/Lib/test/test_iter.py @@ -876,6 +876,21 @@ class TestCase(unittest.TestCase): except TypeError: pass + def test_extending_list_with_iterator_does_not_segfault(self): + # The code to extend a list with an iterator has a fair + # amount of nontrivial logic in terms of guessing how + # much memory to allocate in advance, "stealing" refs, + # and then shrinking at the end. This is a basic smoke + # test for that scenario. + def gen(): + for i in range(500): + yield i + lst = [0] * 500 + for i in range(240): + lst.pop(0) + lst.extend(gen()) + self.assertEqual(len(lst), 760) + def test_main(): run_unittest(TestCase)