https://github.com/python/cpython/commit/bae0ba9ec71e5433c2c634644cefa093f43cc056 commit: bae0ba9ec71e5433c2c634644cefa093f43cc056 branch: 3.13 author: Miss Islington (bot) <[email protected]> committer: serhiy-storchaka <[email protected]> date: 2026-06-21T17:02:30Z summary:
[3.13] gh-150484: Fix mock_open __exit__ with contextlib.ExitStack (GH-151829) (GH-151861) mock_open's _exit_side_effect had a fixed 3-arg signature, but contextlib.ExitStack calls __exit__ with 4 args (self + 3 exc info). Use *args to accept any number of arguments. (cherry picked from commit 85fa295073a0291e517ae6bd24a26e03b5925b75) Co-authored-by: Zang Peiyu <[email protected]> files: A Misc/NEWS.d/next/Library/2026-05-28-00-00-00.gh-issue-150484.XxYyZz.rst M Lib/test/test_unittest/testmock/testmock.py M Lib/unittest/mock.py diff --git a/Lib/test/test_unittest/testmock/testmock.py b/Lib/test/test_unittest/testmock/testmock.py index e1b108f81e513c1..ca4d808620703dd 100644 --- a/Lib/test/test_unittest/testmock/testmock.py +++ b/Lib/test/test_unittest/testmock/testmock.py @@ -2101,6 +2101,15 @@ def test_mock_open_after_eof(self): self.assertEqual([], h.readlines()) self.assertEqual([], h.readlines()) + def test_mock_open_exit_with_contextlib_exit_stack(self): + # gh-150484: mock_open's __exit__ should work when called from + # contextlib.ExitStack, which passes (exctype, excinst, exctb). + from contextlib import ExitStack + with mock.patch('builtins.open', mock.mock_open()) as m: + with ExitStack() as exit_stack: + with exit_stack.enter_context(open('/tmp/test.txt', 'w')): + pass + def test_mock_parents(self): for Klass in Mock, MagicMock: m = Klass() diff --git a/Lib/unittest/mock.py b/Lib/unittest/mock.py index bf32ff6dd3cd9c2..84f629ee1f76ac8 100644 --- a/Lib/unittest/mock.py +++ b/Lib/unittest/mock.py @@ -2991,7 +2991,7 @@ def _next_side_effect(): return handle.readline.return_value return next(_state[0]) - def _exit_side_effect(exctype, excinst, exctb): + def _exit_side_effect(*args): handle.close() global file_spec diff --git a/Misc/NEWS.d/next/Library/2026-05-28-00-00-00.gh-issue-150484.XxYyZz.rst b/Misc/NEWS.d/next/Library/2026-05-28-00-00-00.gh-issue-150484.XxYyZz.rst new file mode 100644 index 000000000000000..522c70058ed29d7 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2026-05-28-00-00-00.gh-issue-150484.XxYyZz.rst @@ -0,0 +1 @@ +Fix :func:`unittest.mock.mock_open` ``__exit__`` raising ``TypeError`` when used with :class:`contextlib.ExitStack`. _______________________________________________ Python-checkins mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3//lists/python-checkins.python.org Member address: [email protected]
