http://hg.python.org/cpython/rev/fc73e6ea9e73 changeset: 77259:fc73e6ea9e73 user: Nick Coghlan <ncoghlan@gmail.com> date: Thu May 31 23:49:26 2012 +1000 summary: Issue #14963: Added test cases for contextlib.ExitStack exception handling behaviour (Initial patch by Alon Horev) files: Lib/test/test_contextlib.py | 89 +++++++++++++++++++++++++ Misc/ACKS | 1 + Misc/NEWS | 11 +++ 3 files changed, 101 insertions(+), 0 deletions(-) diff --git a/Lib/test/test_contextlib.py b/Lib/test/test_contextlib.py --- a/Lib/test/test_contextlib.py +++ b/Lib/test/test_contextlib.py @@ -483,6 +483,95 @@ new_stack.close() self.assertEqual(result, [1, 2, 3]) + def test_exit_raise(self): + with self.assertRaises(ZeroDivisionError): + with ExitStack() as stack: + stack.push(lambda *exc: False) + 1/0 + + def test_exit_suppress(self): + with ExitStack() as stack: + stack.push(lambda *exc: True) + 1/0 + + def test_exit_exception_chaining_reference(self): + # Sanity check to make sure that ExitStack chaining matches + # actual nested with statements + class RaiseExc: + def __init__(self, exc): + self.exc = exc + def __enter__(self): + return self + def __exit__(self, *exc_details): + raise self.exc + + class SuppressExc: + def __enter__(self): + return self + def __exit__(self, *exc_details): + type(self).saved_details = exc_details + return True + + try: + with RaiseExc(IndexError): + with RaiseExc(KeyError): + with RaiseExc(AttributeError): + with SuppressExc(): + with RaiseExc(ValueError): + 1 / 0 + except IndexError as exc: + self.assertIsInstance(exc.__context__, KeyError) + self.assertIsInstance(exc.__context__.__context__, AttributeError) + # Inner exceptions were suppressed + self.assertIsNone(exc.__context__.__context__.__context__) + else: + self.fail("Expected IndexError, but no exception was raised") + # Check the inner exceptions + inner_exc = SuppressExc.saved_details[1] + self.assertIsInstance(inner_exc, ValueError) + self.assertIsInstance(inner_exc.__context__, ZeroDivisionError) + + def test_exit_exception_chaining(self): + # Ensure exception chaining matches the reference behaviour + def raise_exc(exc): + raise exc + + saved_details = None + def suppress_exc(*exc_details): + nonlocal saved_details + saved_details = exc_details + return True + + try: + with ExitStack() as stack: + stack.callback(raise_exc, IndexError) + stack.callback(raise_exc, KeyError) + stack.callback(raise_exc, AttributeError) + stack.push(suppress_exc) + stack.callback(raise_exc, ValueError) + 1 / 0 + except IndexError as exc: + self.assertIsInstance(exc.__context__, KeyError) + self.assertIsInstance(exc.__context__.__context__, AttributeError) + # Inner exceptions were suppressed, but the with statement + # cleanup code adds the one from the body back in as the + # context of the exception raised by the outer callbacks + # See http://bugs.python.org/issue14969 + suite_exc = exc.__context__.__context__.__context__ + self.assertIsInstance(suite_exc, ZeroDivisionError) + else: + self.fail("Expected IndexError, but no exception was raised") + # Check the inner exceptions + inner_exc = saved_details[1] + self.assertIsInstance(inner_exc, ValueError) + self.assertIsInstance(inner_exc.__context__, ZeroDivisionError) + + def test_exit_exception_chaining_suppress(self): + with ExitStack() as stack: + stack.push(lambda *exc: True) + stack.push(lambda *exc: 1/0) + stack.push(lambda *exc: {}[1]) + def test_instance_bypass(self): class Example(object): pass cm = Example() diff --git a/Misc/ACKS b/Misc/ACKS --- a/Misc/ACKS +++ b/Misc/ACKS @@ -460,6 +460,7 @@ Brian Hooper Randall Hopper Nadav Horesh +Alon Horev Jan Hosang Ken Howard Brad Howes diff --git a/Misc/NEWS b/Misc/NEWS --- a/Misc/NEWS +++ b/Misc/NEWS @@ -2,6 +2,17 @@ Python News +++++++++++ +What's New in Python 3.3.0 Beta 1? +=================================== + +*Release date: TBD* + +Tests +----- + +- Issue #14963 (partial): Add test cases for exception handling behaviour + in contextlib.ContextStack (Initial patch by Alon Horev) + What's New in Python 3.3.0 Alpha 4? =================================== -- Repository URL: http://hg.python.org/cpython