Traceback for exit of multi-line `with` statement points to `with (`, rather than the context manager

[Zac-HD]

Bug description:

class CM:
    def __init__(self, fail=False):
        self.fail = fail

    def __enter__(self):
        return self

    def __exit__(self, exc_type, exc_val, exc_tb):
        assert not self.fail


with (
    CM(fail=True) as a,
    CM() as b,
):
    pass

and the traceback should tell us where this failed, right?

Traceback (most recent call last):
  File "repro.py", line 12, in <module>
    with (
  File "repro.py", line 9, in __exit__
    assert not self.fail
AssertionError

In more realistic use-cases¹, it would be very helpful if the traceback pointed to line 13 CM(fail=True) as a, rather than line 12 with (.

I've tested this on Python 3.11, and searching the changelogs for 3.12/13/14 didn't show any related changes.

Footnotes

1. in the case that motivated this issue, I have eleven context managers in one async with statement, which I admit may be excessive - it's certainly motivating. ↩

[StanFromIreland]

On 3.15, 3.14 and 3.13 (the versions that accept bug fixes) I get:

Traceback (most recent call last):
  File "<python-input-0>", line 13, in <module>
    CM(fail=True) as a,
    ~~^^^^^^^^^^^
  File "<python-input-0>", line 9, in __exit__
    assert not self.fail
           ^^^^^^^^^^^^^
AssertionError

What version did you get that traceback with? From my understanding of your post, 3.11? Unfortunately there is nothing to be done there, it only accepts security fixes.

[Zac-HD]

Ah, you're right - I haven't been able to find this in the issues, prs, or docs; but when I install a new enough Python it does indeed work as I wished! Another item for the list of reasons to upgrade... 😁