[issue36626] asyncio run_forever blocks indefinitely

[Dan Timofte]

New submission from Dan Timofte :

after starting run_forever if all scheduled tasks are consumed run_once will 
issue a KqueueSelector.select(None) which will block indefinitely :
https://www.freebsd.org/cgi/man.cgi?query=select&sektion=2&apropos=0&manpath=FreeBSD+12.0-RELEASE+and+Ports#DESCRIPTION

after this new tasks are not being processed, trying to stop event loop with 
stop() is not working.

this blocks immediatly : 
import asyncio
import sys
import signal


def cb_signal_handler(signum, frame):
asyncio.get_event_loop().stop()


def main():
signal.signal(signal.SIGINT, cb_signal_handler)

# asyncio.get_event_loop().create_task(asyncio.sleep(1))
asyncio.get_event_loop().run_forever()

main()

With asyncio.sleep uncomment it will block after 4 cycles.

--
components: asyncio, macOS
messages: 340182
nosy: asvetlov, dantimofte, ned.deily, ronaldoussoren, yselivanov
priority: normal
severity: normal
status: open
title: asyncio run_forever blocks indefinitely
versions: Python 3.7

___
Python tracker 
<https://bugs.python.org/issue36626>
___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue36626] asyncio run_forever blocks indefinitely

[Dan Timofte]

Change by Dan Timofte :


--
type:  -> behavior

___
Python tracker 
<https://bugs.python.org/issue36626>
___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue36626] asyncio run_forever blocks indefinitely

[Dan Timofte]

Dan Timofte  added the comment:

i will provide a patch, i'll make a pull request next week.

a call to self._write_to_self() should also be added to create_task() before it 
returns . i'll make the correction for this as well.

--

___
Python tracker 
<https://bugs.python.org/issue36626>
___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue36626] asyncio run_forever blocks indefinitely

[Dan Timofte]

Change by Dan Timofte :


--
keywords: +patch
pull_requests: +12770
stage:  -> patch review

___
Python tracker 
<https://bugs.python.org/issue36626>
___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue36626] asyncio run_forever blocks indefinitely

[Dan Timofte]

Dan Timofte  added the comment:

`loop.call_soon_threadsafe(loop.stop)` solves the problem because it has the 
write_to_self there. I can use that or call loop._write_to_self() myself before 
calling loop.stop(). 

In my code i'm stoping the loop from the exception_handler not signal. The code 
was a small example i thought of that reproduces the described behaviour.

You can close the issue if it's ok for you.

--

___
Python tracker 
<https://bugs.python.org/issue36626>
___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com