import logging
with logging.disable('WARN'): pass

See: https://github.com/ipython/ipython/issues/12713
I'm not actually sure what's happening here, just reporting.

Reporting what? Please elaborate.

Everything's in the linked issue; in summary, the command kills IPython, and an IPython maintainer showed code suggesting the problem's rooted in CPython's improper handling of 'WARN' as alias for logging.WARN.

The problem seems to be in the user code? As you were told by "Carreau", loggin.disable takes a logging level (an integer), since you're giving it a string which it dutifully stores, it blows up at the next logging call which happens to be in asyncio.

This is not an asyncio bug, nor is it a crash anymore than passing a broken key function to `sorted` is a *Python* crash.

At most it's an enancement request: `logging.disable` could raise a TypeError immediately or convert the value to a loglevel the way `setLevel` does instead of storing the broken value as-is (all it does currently is store the value it receives on the root logger without any check).

I should have been more careful in my explanation in the upstream issue to have a complete report in here. 

I think that patching logging.disable to raise a type error immediately would be welcome; as the effect of storing a wrong type make any asyncio application fails in place that can be relatively remote from the location of the erroneous value, and could be quite hard to debug in other circumstances.

> I think that patching logging.disable to raise a type error immediately would be welcome

FWIW `logging` has a built-in checker / converter[0] which is already used in a bunch of places (e.g. the aforementioned setLevel), it could just be added inside `disable` in the same way it's used in setLevel[1] and would uniformly convert "level names" to proper levels or raise an error. That seems like a really easy patch / contribution.

[0] https://github.com/python/cpython/blob/3.9/Lib/logging/__init__.py#L189

[1] https://github.com/python/cpython/blob/3.9/Lib/logging/__init__.py#L906

Oh I now see you've created a PR to do essentially that, nm.

New changeset b32d8b4f9bcd2e7d11240b6b9de0262cf8f5e09d by Matthias Bussonnier in branch 'master':
bpo-42644: Validate values in logging.disable() (#23786)
https://github.com/python/cpython/commit/b32d8b4f9bcd2e7d11240b6b9de0262cf8f5e09d

New changeset 0a24a57888798905e3b8891c59e61ed4f1bfc5a8 by Miss Islington (bot) in branch '3.8':
bpo-42644: Validate values in logging.disable() (GH-23786)
https://github.com/python/cpython/commit/0a24a57888798905e3b8891c59e61ed4f1bfc5a8

New changeset db63da7e5d4a98925a04f903a19bf3595b9c2c46 by Miss Islington (bot) in branch '3.9':
bpo-42644: Validate values in logging.disable() (GH-23786)
https://github.com/python/cpython/commit/db63da7e5d4a98925a04f903a19bf3595b9c2c46