[issue39010] ProactorEventLoop raises unhandled ConnectionResetError

[Jonathan Slenders]

New submission from Jonathan Slenders <jonathan.slenders at gmail.com>:

We have a snippet of code that runs perfectly fine using the `SelectorEventLoop`, but crashes *sometimes* using the `ProactorEventLoop`.

The traceback is the following. The exception cannot be caught within the asyncio application itself (e.g., it is not attached to any Future or propagated in a coroutine). It probably propagates in `run_until_complete()`.

  File "C:\Python38\lib\asyncio\proactor_events.py", line 768, in _loop_self_reading
    f.result()  # may raise
  File "C:\Python38\lib\asyncio\windows_events.py", line 808, in _poll
    value = callback(transferred, key, ov)
  File "C:\Python38\lib\asyncio\windows_events.py", line 457, in finish_recv
    raise ConnectionResetError(*exc.args)

I can see that in `IocpProactor._poll`, `OSError` is caught and attached to the future, but not `ConnectionResetError`. I would expect that `ConnectionResetError` too will be attached to the future.

In order to reproduce, run the following snippet on Python 3.8:

from prompt_toolkit import prompt  # pip install prompt_toolkit
while 1:
    prompt('>')

Hold down the enter key, and it'll trigger quickly.

See also: https://github.com/prompt-toolkit/python-prompt-toolkit/issues/1023

----------
components: asyncio
messages: 358140
nosy: Jonathan Slenders, asvetlov, yselivanov
priority: normal
severity: normal
status: open
title: ProactorEventLoop raises unhandled ConnectionResetError
versions: Python 3.8

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue39010>
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