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bpo-44471: Change error type for bad objects in ExitStack.enter_context() (GH-26820)

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A TypeError is now raised instead of an AttributeError in
ExitStack.enter_context() and AsyncExitStack.enter_async_context()
for objects which do not support the context manager or
asynchronous context manager protocols correspondingly.
This commit is contained in:
Serhiy Storchaka 2021-06-29 11:28:15 +03:00 • committed by GitHub
parent 20a88004ba
commit 6cb145d23f
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6 changed files with 91 additions and 8 deletions
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23
Lib/test/test_contextlib.py
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@ -661,6 +661,25 @@ class TestBaseExitStack:
result.append(2)
self.assertEqual(result, [1, 2, 3, 4])
def test_enter_context_errors(self):
class LacksEnterAndExit:
pass
class LacksEnter:
def __exit__(self, *exc_info):
pass
class LacksExit:
def __enter__(self):
pass
with self.exit_stack() as stack:
with self.assertRaisesRegex(TypeError, 'the context manager'):
stack.enter_context(LacksEnterAndExit())
with self.assertRaisesRegex(TypeError, 'the context manager'):
stack.enter_context(LacksEnter())
with self.assertRaisesRegex(TypeError, 'the context manager'):
stack.enter_context(LacksExit())
self.assertFalse(stack._exit_callbacks)
def test_close(self):
result = []
with self.exit_stack() as stack:
@ -886,9 +905,11 @@ class TestBaseExitStack:
def test_instance_bypass(self):
class Example(object): pass
cm = Example()
cm.__enter__ = object()
cm.__exit__ = object()
stack = self.exit_stack()
self.assertRaises(AttributeError, stack.enter_context, cm)
with self.assertRaisesRegex(TypeError, 'the context manager'):
stack.enter_context(cm)
stack.push(cm)
self.assertIs(stack._exit_callbacks[-1][1], cm)