Issue 33650: asyncio: Prohibit adding a signal handler for SIGCHLD (original) (raw)

Issue33650

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classification

Title:	asyncio: Prohibit adding a signal handler for SIGCHLD
Type:	Stage:
Components:	asyncio	Versions:	Python 3.8

process

Status:	open	Resolution:
Dependencies:		Superseder:
Assigned To:		Nosy List:	asvetlov, gregory.p.smith, pitrou, yselivanov
Priority:	normal	Keywords:

Created on 2018-05-25 20:56 by yselivanov, last changed 2022-04-11 14:59 by admin.

Messages (3)
msg317717 - (view)	Author: Yury Selivanov (yselivanov) *	Date: 2018-05-25 20:56
Doing that will break subprocesses.
msg318454 - (view)	Author: Yury Selivanov (yselivanov) *	Date: 2018-06-01 19:00
To clarify this ticket: I'm talking about prohibiting `loop.add_signal_handler(SIGCHLD)` as it would break child processes watchers that asyncio installs. In other words, setting a custom SIGCHLD breaks asyncio internals. We can allow user-set SIGCHLD signals if we add some code to make sure that 'add_signal_handler(SIGCHLD)' delivers the signal to both asyncio internals and user code. But I'm not sure if there's a valid use case for listening for SIGCHLD for user code at all. For now, I disabled SIGCHLD in uvloop, let's see if people complain.
msg318455 - (view)	Author: Antoine Pitrou (pitrou) *	Date: 2018-06-01 19:41
Some people may have reasons to do that (for example: they write their own subprocess implementation). I suggest emitting a warning rather than forbidding it.

History
Date	User	Action	Args
2022-04-11 14:59:00	admin	set	github: 77831
2018-06-01 19:41:05	pitrou	set	nosy: + pitroumessages: +
2018-06-01 19:39:53	pitrou	set	title: Prohibit adding a signal handler for SIGCHLD -> asyncio: Prohibit adding a signal handler for SIGCHLD
2018-06-01 19:00:39	yselivanov	set	messages: +
2018-06-01 18:51:18	ned.deily	set	nosy: + gregory.p.smith
2018-05-25 20:56:35	yselivanov	create