Message 326896 - Python tracker

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Author	yselivanov
Recipients	Elvis.Pranskevichus, asvetlov, yselivanov
Date	2018-10-02.19:30:37
SpamBayes Score	-1.0
Marked as misclassified	Yes
Message-id	<1538508638.07.0.545547206417.issue34872@psf.upfronthosting.co.za>
In-reply-to

Content
Vladimir Matveev has discovered that C and Python implementation of asyncio.Task diverge: * asynciomodule.c: https://github.com/python/cpython/blob/9012a0fb4c4ec1afef9efb9fdb0964554ea17983/Modules/_asynciomodule.c#L2716 * tasks.py: https://github.com/python/cpython/blob/9012a0fb4c4ec1afef9efb9fdb0964554ea17983/Lib/asyncio/tasks.py#L286 In tasks.py we call "fut_obj.cancel()", so either "Task.cancel()" or "Future.cancel()" can be called depending on what "fut_obj" is. In asynciomodule.c we essentially always call "Future.cancel(fut_obj)". This probably leads to unexpected behaviour if "fut_obj" is either a Task or a Task subclass with an overloaded "cancel()" method. We need to first write a set of tests to understand the scope of this; then we'll need to patch asynciomodule.c and backport this to 3.7 & 3.6.

Vladimir Matveev has discovered that C and Python implementation of asyncio.Task diverge:

* asynciomodule.c:
https://github.com/python/cpython/blob/9012a0fb4c4ec1afef9efb9fdb0964554ea17983/Modules/_asynciomodule.c#L2716

* tasks.py:
https://github.com/python/cpython/blob/9012a0fb4c4ec1afef9efb9fdb0964554ea17983/Lib/asyncio/tasks.py#L286

In tasks.py we call "fut_obj.cancel()", so either "Task.cancel()" or "Future.cancel()" can be called depending on what "fut_obj" is.

In asynciomodule.c we essentially always call "Future.cancel(fut_obj)".  This probably leads to unexpected behaviour if "fut_obj" is either a Task or a Task subclass with an overloaded "cancel()" method.

We need to first write a set of tests to understand the scope of this; then we'll need to patch asynciomodule.c and backport this to 3.7 & 3.6.

History
Date	User	Action	Args
2018-10-02 19:30:38	yselivanov	set	recipients: + yselivanov, asvetlov, Elvis.Pranskevichus
2018-10-02 19:30:38	yselivanov	set	messageid: <1538508638.07.0.545547206417.issue34872@psf.upfronthosting.co.za>
2018-10-02 19:30:38	yselivanov	link	issue34872 messages
2018-10-02 19:30:37	yselivanov	create