Issue 35409: Async generator might re-throw GeneratorExit on aclose() - Python tracker

classification

Title:	Async generator might re-throw GeneratorExit on aclose()
Type:	behavior	Stage:	resolved
Components:	Interpreter Core	Versions:	Python 3.9, Python 3.8, Python 3.7

process

Status:	closed	Resolution:	fixed
Dependencies:		Superseder:
Assigned To:		Nosy List:	miss-islington, vxgmichel
Priority:	normal	Keywords:	patch

Created on 2018-12-04 13:21 by vxgmichel, last changed 2019-11-19 14:12 by miss-islington. This issue is now closed.

Files
File name	Uploaded	Description	Edit
example.py	vxgmichel, 2018-12-04 13:21	Reproduce the issue with asyncio
test.py	vxgmichel, 2018-12-04 13:22	Reproduce the issue without asyncio
patch.diff	vxgmichel, 2018-12-04 13:22	A possible fix

Pull Requests
URL	Status	Linked	Edit
PR 14755	merged	vxgmichel, 2019-07-13 16:04
PR 17257	merged	miss-islington, 2019-11-19 13:54
PR 17258	merged	miss-islington, 2019-11-19 13:54

Messages (4)
msg331043 - (view)	Author: Vincent Michel (vxgmichel) *	Date: 2018-12-04 13:21
As far as I can tell, this issue is different than: https://bugs.python.org/issue34730 I noticed `async_gen.aclose()` raises a GeneratorExit exception if the async generator finalization awaits and silence a failing unfinished future (see example.py). This seems to be related to a bug in `async_gen_athrow_throw`. In fact, `async_gen.aclose().throw(exc)` does not silence GeneratorExit exceptions. This behavior can be reproduced without asyncio (see test.py). Attached is a possible patch, although I'm not too comfortable messing with the python C internals. I can make a PR if necessary.
msg356968 - (view)	Author: miss-islington (miss-islington)	Date: 2019-11-19 13:53
New changeset 8e0de2a4808d7c2f4adedabff89ee64e0338790a by Miss Islington (bot) (Vincent Michel) in branch 'master': bpo-35409: Ignore GeneratorExit in async_gen_athrow_throw (GH-14755) https://github.com/python/cpython/commit/8e0de2a4808d7c2f4adedabff89ee64e0338790a
msg356969 - (view)	Author: miss-islington (miss-islington)	Date: 2019-11-19 14:12
New changeset 6c3b471c8c0bfd49c664d8ee7e95da3710fd6069 by Miss Islington (bot) in branch '3.8': bpo-35409: Ignore GeneratorExit in async_gen_athrow_throw (GH-14755) https://github.com/python/cpython/commit/6c3b471c8c0bfd49c664d8ee7e95da3710fd6069
msg356970 - (view)	Author: miss-islington (miss-islington)	Date: 2019-11-19 14:12
New changeset 4ffc569b47bef9f95e443f3c56f7e7e32cb440c0 by Miss Islington (bot) in branch '3.7': bpo-35409: Ignore GeneratorExit in async_gen_athrow_throw (GH-14755) https://github.com/python/cpython/commit/4ffc569b47bef9f95e443f3c56f7e7e32cb440c0

History
Date	User	Action	Args
2019-11-19 14:12:24	miss-islington	set	messages: + msg356970
2019-11-19 14:12:17	miss-islington	set	messages: + msg356969
2019-11-19 13:55:48	asvetlov	set	status: open -> closed stage: patch review -> resolved resolution: fixed versions: + Python 3.9, - Python 3.6
2019-11-19 13:54:47	miss-islington	set	pull_requests: + pull_request16752
2019-11-19 13:54:10	miss-islington	set	pull_requests: + pull_request16751
2019-11-19 13:53:56	miss-islington	set	nosy: + miss-islington messages: + msg356968
2019-07-13 16:04:04	vxgmichel	set	stage: patch review pull_requests: + pull_request14550
2018-12-04 13:22:28	vxgmichel	set	files: + patch.diff keywords: + patch
2018-12-04 13:22:10	vxgmichel	set	files: + test.py
2018-12-04 13:21:20	vxgmichel	create