diff options
| -rw-r--r-- | Lib/contextlib.py | 4 | ||||
| -rw-r--r-- | Lib/test/test_contextlib.py | 58 |
2 files changed, 49 insertions, 13 deletions
diff --git a/Lib/contextlib.py b/Lib/contextlib.py index ca7a79d..82ee955 100644 --- a/Lib/contextlib.py +++ b/Lib/contextlib.py @@ -298,7 +298,7 @@ class ExitStack(object): # we were actually nesting multiple with statements frame_exc = sys.exc_info()[1] def _fix_exception_context(new_exc, old_exc): - # Context isn't what we want, so find the end of the chain + # Context may not be correct, so find the end of the chain while 1: exc_context = new_exc.__context__ if exc_context is old_exc: @@ -306,8 +306,6 @@ class ExitStack(object): return if exc_context is None or exc_context is frame_exc: break - details = id(new_exc), id(old_exc), id(exc_context) - raise Exception(str(details)) new_exc = exc_context # Change the end of the chain to point to the exception # we expect it to reference diff --git a/Lib/test/test_contextlib.py b/Lib/test/test_contextlib.py index f947232..39cc776 100644 --- a/Lib/test/test_contextlib.py +++ b/Lib/test/test_contextlib.py @@ -629,24 +629,62 @@ class TestExitStack(unittest.TestCase): def test_exit_exception_with_correct_context(self): # http://bugs.python.org/issue20317 @contextmanager - def gets_the_context_right(): + def gets_the_context_right(exc): try: - yield 6 + yield finally: - 1 / 0 + raise exc + + exc1 = Exception(1) + exc2 = Exception(2) + exc3 = Exception(3) + exc4 = Exception(4) # The contextmanager already fixes the context, so prior to the # fix, ExitStack would try to fix it *again* and get into an # infinite self-referential loop try: with ExitStack() as stack: - stack.enter_context(gets_the_context_right()) - stack.enter_context(gets_the_context_right()) - stack.enter_context(gets_the_context_right()) - except ZeroDivisionError as exc: - self.assertIsInstance(exc.__context__, ZeroDivisionError) - self.assertIsInstance(exc.__context__.__context__, ZeroDivisionError) - self.assertIsNone(exc.__context__.__context__.__context__) + stack.enter_context(gets_the_context_right(exc4)) + stack.enter_context(gets_the_context_right(exc3)) + stack.enter_context(gets_the_context_right(exc2)) + raise exc1 + except Exception as exc: + self.assertIs(exc, exc4) + self.assertIs(exc.__context__, exc3) + self.assertIs(exc.__context__.__context__, exc2) + self.assertIs(exc.__context__.__context__.__context__, exc1) + self.assertIsNone( + exc.__context__.__context__.__context__.__context__) + + def test_exit_exception_with_existing_context(self): + # Addresses a lack of test coverage discovered after checking in a + # fix for issue 20317 that still contained debugging code. + def raise_nested(inner_exc, outer_exc): + try: + raise inner_exc + finally: + raise outer_exc + exc1 = Exception(1) + exc2 = Exception(2) + exc3 = Exception(3) + exc4 = Exception(4) + exc5 = Exception(5) + try: + with ExitStack() as stack: + stack.callback(raise_nested, exc4, exc5) + stack.callback(raise_nested, exc2, exc3) + raise exc1 + except Exception as exc: + self.assertIs(exc, exc5) + self.assertIs(exc.__context__, exc4) + self.assertIs(exc.__context__.__context__, exc3) + self.assertIs(exc.__context__.__context__.__context__, exc2) + self.assertIs( + exc.__context__.__context__.__context__.__context__, exc1) + self.assertIsNone( + exc.__context__.__context__.__context__.__context__.__context__) + def test_body_exception_suppress(self): |