#3720: Interpreter crashes when an evil iterator removes its own next function.

Now the slot is filled with a function that always raises.

Will not backport: extensions compiled with 2.6.x would not run on 2.6.0.

1 files changed, 22 insertions, 0 deletions

diff --git a/Lib/test/test_iter.py b/Lib/test/test_iter.py
index f83de78..e847018 100644
--- a/Lib/test/test_iter.py
+++ b/Lib/test/test_iter.py
@@ -120,6 +120,13 @@ class TestCase(unittest.TestCase):
     def test_seq_class_iter(self):
         self.check_iterator(iter(SequenceClass(10)), range(10))
 
+    # Test a new_style class with __iter__ but no next() method
+    def test_new_style_iter_class(self):
+        class IterClass(object):
+            def __iter__(self):
+                return self
+        self.assertRaises(TypeError, iter, IterClass())
+
     # Test two-argument iter() with callable instance
     def test_iter_callable(self):
         class C:
@@ -877,6 +884,21 @@ class TestCase(unittest.TestCase):
         self.assertEqual(list(b), zip(range(5), range(5)))
         self.assertEqual(list(b), [])
 
+    def test_3720(self):
+        # Avoid a crash, when an iterator deletes its next() method.
+        class BadIterator(object):
+            def __iter__(self):
+                return self
+            def next(self):
+                del BadIterator.next
+                return 1
+
+        try:
+            for i in BadIterator() :
+                pass
+        except TypeError:
+            pass
+
 
 def test_main():
     run_unittest(TestCase)