Issue #13454: Fix a crash when deleting an iterator created by itertools.tee()
if all other iterators were very advanced before.
diff --git a/Lib/test/test_itertools.py b/Lib/test/test_itertools.py
index 8cdc597..66e307d 100644
--- a/Lib/test/test_itertools.py
+++ b/Lib/test/test_itertools.py
@@ -930,6 +930,14 @@
del a
self.assertRaises(ReferenceError, getattr, p, '__class__')
+ # Issue 13454: Crash when deleting backward iterator from tee()
+ def test_tee_del_backward(self):
+ forward, backward = tee(range(20000000))
+ for i in forward:
+ pass
+
+ del backward
+
def test_StopIteration(self):
self.assertRaises(StopIteration, next, zip())