From b3722ca058f6a6d6505cf2ea9ffabaf7fb6b6e19 Mon Sep 17 00:00:00 2001 From: Thomas Grainger Date: Tue, 3 Jan 2023 15:47:13 +0000 Subject: [PATCH] gh-95882: fix regression in the traceback of exceptions propagated from inside a contextlib context manager (#95883) --- Lib/contextlib.py | 5 +- Lib/test/test_contextlib.py | 30 +++++++++- Lib/test/test_contextlib_async.py | 57 +++++++++++++++++++ Misc/ACKS | 1 + ...2-08-11-10-02-19.gh-issue-95882.FsUr72.rst | 1 + 5 files changed, 90 insertions(+), 4 deletions(-) create mode 100644 Misc/NEWS.d/next/Library/2022-08-11-10-02-19.gh-issue-95882.FsUr72.rst diff --git a/Lib/contextlib.py b/Lib/contextlib.py index d5822219b3e..30d9ac25b2b 100644 --- a/Lib/contextlib.py +++ b/Lib/contextlib.py @@ -173,7 +173,7 @@ class _GeneratorContextManager( isinstance(value, StopIteration) and exc.__cause__ is value ): - exc.__traceback__ = traceback + value.__traceback__ = traceback return False raise except BaseException as exc: @@ -228,6 +228,7 @@ class _AsyncGeneratorContextManager( except RuntimeError as exc: # Don't re-raise the passed in exception. (issue27122) if exc is value: + exc.__traceback__ = traceback return False # Avoid suppressing if a Stop(Async)Iteration exception # was passed to athrow() and later wrapped into a RuntimeError @@ -239,6 +240,7 @@ class _AsyncGeneratorContextManager( isinstance(value, (StopIteration, StopAsyncIteration)) and exc.__cause__ is value ): + value.__traceback__ = traceback return False raise except BaseException as exc: @@ -250,6 +252,7 @@ class _AsyncGeneratorContextManager( # and the __exit__() protocol. if exc is not value: raise + exc.__traceback__ = traceback return False raise RuntimeError("generator didn't stop after athrow()") diff --git a/Lib/test/test_contextlib.py b/Lib/test/test_contextlib.py index 31f5c74572b..ec06785b566 100644 --- a/Lib/test/test_contextlib.py +++ b/Lib/test/test_contextlib.py @@ -104,15 +104,39 @@ class ContextManagerTestCase(unittest.TestCase): self.assertEqual(frames[0].line, '1/0') # Repeat with RuntimeError (which goes through a different code path) + class RuntimeErrorSubclass(RuntimeError): + pass + try: with f(): - raise NotImplementedError(42) - except NotImplementedError as e: + raise RuntimeErrorSubclass(42) + except RuntimeErrorSubclass as e: frames = traceback.extract_tb(e.__traceback__) self.assertEqual(len(frames), 1) self.assertEqual(frames[0].name, 'test_contextmanager_traceback') - self.assertEqual(frames[0].line, 'raise NotImplementedError(42)') + self.assertEqual(frames[0].line, 'raise RuntimeErrorSubclass(42)') + + class StopIterationSubclass(StopIteration): + pass + + for stop_exc in ( + StopIteration('spam'), + StopIterationSubclass('spam'), + ): + with self.subTest(type=type(stop_exc)): + try: + with f(): + raise stop_exc + except type(stop_exc) as e: + self.assertIs(e, stop_exc) + frames = traceback.extract_tb(e.__traceback__) + else: + self.fail(f'{stop_exc} was suppressed') + + self.assertEqual(len(frames), 1) + self.assertEqual(frames[0].name, 'test_contextmanager_traceback') + self.assertEqual(frames[0].line, 'raise stop_exc') def test_contextmanager_no_reraise(self): @contextmanager diff --git a/Lib/test/test_contextlib_async.py b/Lib/test/test_contextlib_async.py index b64673d2c31..3d43ed0fcab 100644 --- a/Lib/test/test_contextlib_async.py +++ b/Lib/test/test_contextlib_async.py @@ -5,6 +5,7 @@ from contextlib import ( import functools from test import support import unittest +import traceback from test.test_contextlib import TestBaseExitStack @@ -125,6 +126,62 @@ class AsyncContextManagerTestCase(unittest.TestCase): raise ZeroDivisionError() self.assertEqual(state, [1, 42, 999]) + @_async_test + async def test_contextmanager_traceback(self): + @asynccontextmanager + async def f(): + yield + + try: + async with f(): + 1/0 + except ZeroDivisionError as e: + frames = traceback.extract_tb(e.__traceback__) + + self.assertEqual(len(frames), 1) + self.assertEqual(frames[0].name, 'test_contextmanager_traceback') + self.assertEqual(frames[0].line, '1/0') + + # Repeat with RuntimeError (which goes through a different code path) + class RuntimeErrorSubclass(RuntimeError): + pass + + try: + async with f(): + raise RuntimeErrorSubclass(42) + except RuntimeErrorSubclass as e: + frames = traceback.extract_tb(e.__traceback__) + + self.assertEqual(len(frames), 1) + self.assertEqual(frames[0].name, 'test_contextmanager_traceback') + self.assertEqual(frames[0].line, 'raise RuntimeErrorSubclass(42)') + + class StopIterationSubclass(StopIteration): + pass + + class StopAsyncIterationSubclass(StopAsyncIteration): + pass + + for stop_exc in ( + StopIteration('spam'), + StopAsyncIteration('ham'), + StopIterationSubclass('spam'), + StopAsyncIterationSubclass('spam') + ): + with self.subTest(type=type(stop_exc)): + try: + async with f(): + raise stop_exc + except type(stop_exc) as e: + self.assertIs(e, stop_exc) + frames = traceback.extract_tb(e.__traceback__) + else: + self.fail(f'{stop_exc} was suppressed') + + self.assertEqual(len(frames), 1) + self.assertEqual(frames[0].name, 'test_contextmanager_traceback') + self.assertEqual(frames[0].line, 'raise stop_exc') + @_async_test async def test_contextmanager_no_reraise(self): @asynccontextmanager diff --git a/Misc/ACKS b/Misc/ACKS index d50cb3c2d1e..b4e309c6905 100644 --- a/Misc/ACKS +++ b/Misc/ACKS @@ -645,6 +645,7 @@ Hans de Graaff Tim Graham Kim Gräsman Alex Grönholm +Thomas Grainger Nathaniel Gray Eddy De Greef Duane Griffin diff --git a/Misc/NEWS.d/next/Library/2022-08-11-10-02-19.gh-issue-95882.FsUr72.rst b/Misc/NEWS.d/next/Library/2022-08-11-10-02-19.gh-issue-95882.FsUr72.rst new file mode 100644 index 00000000000..9cdb237d5c8 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2022-08-11-10-02-19.gh-issue-95882.FsUr72.rst @@ -0,0 +1 @@ +Fix a 3.11 regression in :func:`~contextlib.asynccontextmanager`, which caused it to propagate exceptions with incorrect tracebacks and fix a 3.11 regression in :func:`~contextlib.contextmanager`, which caused it to propagate exceptions with incorrect tracebacks for :exc:`StopIteration`.