[Python-Dev] Re: Behavior of `asyncio.gather` when one of submitted tasks raises a `KeyboardInterrupt`.

9 Jun 2022

      Thank you for the straightforward explanation. May I ask you another question?
I don't understand the behavior of this waiting primitive. So here is the case below:
```py
import asyncio

e = KeyboardInterrupt  # or SystemExit
async def sub_task():
    raise e

async def main_task():
    try:
        await asyncio.gather(
            # -- aws --
            sub_task(),
            asyncio.sleep(0)
        )
    except Exception as e:
        print('\tmain_task(), e:', repr(e))
        raise
    except BaseException as e:
        print('\tmain_task(), be:', repr(e))

if __name__ == '__main__':
    try:
        asyncio.run(main_task())
    except e:
        print(f'__main__ {e}')
```
When one coroutine `[sub_task()]`, result is:
        main_task(), be: CancelledError()
__main__ <class 'KeyboardInterrupt'>

When two coroutines `[sub_task(), sleep(0)]` , result is:
        main_task(), be: KeyboardInterrupt()
__main__ <class 'KeyboardInterrupt'>

Why are results so different when `aws` contains single coroutine or two coroutines ?
Thank for your time
Yves

Guido van Rossum wrote:
...
KeyboardInterrupt is generally not handled properly by asyncio, the normal
behavior here is that the code just exits with a traceback.
On Tue, Jun 7, 2022 at 11:00 AM Yves Duprat yduprat@gmail.com wrote:
...
Hi,
regarding this [issue93122](https://github.com/python/cpython/issues/93122),
I am wondering what is the normal behavior of `asyncio.gather` when one of
the submitted tasks raises a `KeyboardInterrupt` exception ? -- regardless
of the value of the `return_exception` parameter.
It seems that this primitive does not behave the same way with
`KeyboardInterrupt` and `ZeroDivisionError` exceptions. But may be it is
normal ?
I have searched in the documentation [here](
https://docs.python.org/3/library/asyncio-task.html#asyncio.gather) but I
did not find anything.
Thanks for your help.
Yves
_______________________________________________
Python-Dev mailing list -- python-dev@python.org
To unsubscribe send an email to python-dev-leave@python.org
https://mail.python.org/mailman3/lists/python-dev.python.org/
Message archived at
https://mail.python.org/archives/list/python-dev@python.org/message/5KVY7SSD...
Code of Conduct: http://python.org/psf/codeofconduct/
-- 
--Guido van Rossum (python.org/~guido)
*Pronouns: he/him **(why is my pronoun here?)*
http://feministing.com/2015/02/03/how-using-they-as-a-singular-pronoun-can-c...