diff --git a/Lib/contextlib.py b/Lib/contextlib.py index 962cedab490eb2..2f00dabf6ff38b 100644 --- a/Lib/contextlib.py +++ b/Lib/contextlib.py @@ -83,6 +83,9 @@ def _recreate_cm(self): return self.__class__(self.func, self.args, self.kwds) def __enter__(self): + # do not keep args and kwds alive unnecessarily + # they are only needed for recreation, which is not possible anymore + del self.args, self.kwds, self.func try: return next(self.gen) except StopIteration: diff --git a/Lib/test/test_contextlib.py b/Lib/test/test_contextlib.py index 64b6578ff94eb3..76ff0d2204a942 100644 --- a/Lib/test/test_contextlib.py +++ b/Lib/test/test_contextlib.py @@ -7,6 +7,7 @@ import unittest from contextlib import * # Tests __all__ from test import support +import weakref class TestAbstractContextManager(unittest.TestCase): @@ -218,6 +219,52 @@ def woohoo(self, func, args, kwds): with woohoo(self=11, func=22, args=33, kwds=44) as target: self.assertEqual(target, (11, 22, 33, 44)) + def test_nokeepref(self): + class A: + pass + + @contextmanager + def woohoo(a, b): + a = weakref.ref(a) + b = weakref.ref(b) + self.assertIsNone(a()) + self.assertIsNone(b()) + yield + + with woohoo(A(), b=A()): + pass + + def test_param_errors(self): + @contextmanager + def woohoo(a, *, b): + yield + + with self.assertRaises(TypeError): + woohoo() + with self.assertRaises(TypeError): + woohoo(3, 5) + with self.assertRaises(TypeError): + woohoo(b=3) + + def test_recursive(self): + depth = 0 + @contextmanager + def woohoo(): + nonlocal depth + before = depth + depth += 1 + yield + depth -= 1 + self.assertEqual(depth, before) + + @woohoo() + def recursive(): + if depth < 10: + recursive() + + recursive() + self.assertEqual(depth, 0) + class ClosingTestCase(unittest.TestCase):