diff options
Diffstat (limited to 'Lib/contextlib.py')
| -rw-r--r-- | Lib/contextlib.py | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/Lib/contextlib.py b/Lib/contextlib.py index f8e026b7e2f..f87828569a1 100644 --- a/Lib/contextlib.py +++ b/Lib/contextlib.py @@ -231,11 +231,19 @@ 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 while 1: exc_context = new_exc.__context__ - if exc_context in (None, frame_exc): + if exc_context is old_exc: + # Context is already set correctly (see issue 20317) + 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 new_exc.__context__ = old_exc # Callbacks are invoked in LIFO order to match the behaviour of |