[New-bugs-announce] [issue32684] asyncio.gather(..., return_exceptions=True) swallows cancellation

[Марк Коренберг]

New submission from Марк Коренберг <socketpair at gmail.com>:

Proof:

================
import asyncio

async def test():
    while True:
        print('sleeping 1')
        await asyncio.gather(asyncio.sleep(1), return_exceptions=True)

async def amain():
    print('creating task')
    qwe = asyncio.Task(test())
    print('sleeping 2')
    await asyncio.sleep(2)
    print('cancelling task')
    qwe.cancel()
    print('waiting task for completion')
    try:
        await qwe
    except Exception as e:
        print('task complete: %r', e)

loop = asyncio.get_event_loop()
loop.run_until_complete(amain())

================

This program will never complete.

This case should be either fixed, or documented.

----------
components: asyncio
messages: 310843
nosy: asvetlov, socketpair, yselivanov
priority: normal
severity: normal
status: open
title: asyncio.gather(..., return_exceptions=True) swallows cancellation
type: behavior
versions: Python 3.5, Python 3.6, Python 3.7, Python 3.8

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue32684>
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