[New-bugs-announce] [issue24598] asyncio: add background task detecting reference cycles

[STINNER Victor]

New submission from STINNER Victor:

When storing an exception in an asyncio Future object, there is a high risk of creating a reference cycle. In Python 3, exception objects store a traceback object which store frame objects. The problem is that a frame can also have a reference to the exception: we have a reference cycle (exception -> traceback -> frame -> same exception).

In debug mode, Future.set_exception() can schedule a task (ex: using loop.call_soon) to check that there is no reference cycle.

See also the issue #23587: "asyncio: use the new traceback.TracebackException class".

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components: asyncio
messages: 246499
nosy: gvanrossum, haypo, yselivanov
priority: normal
severity: normal
status: open
title: asyncio: add background task detecting reference cycles
versions: Python 3.6

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue24598>
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