[New-bugs-announce] [issue31323] test_ssl: reference cycle between ThreadedEchoServer and its ConnectionHandler

[STINNER Victor]

New submission from STINNER Victor:

While testing bpo-31234 fix, I noticed that some test_ssl tests using ThreadedEchoServer create reference cycles with ConnectionHandler: ConnectionHandler fills ThreadedEchoServer.conn_errors with exceptions, but exceptions keep an alive traceback object which contains frame locals.

I tried to use traceback.clear_frames(), but this function is broken: see bpo-31321.

Attached PR works around the issue by storing errors are text rather than objects.

The PR prevents warnings about dangling threads.

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components: Tests
messages: 301116
nosy: haypo
priority: normal
severity: normal
status: open
title: test_ssl: reference cycle between ThreadedEchoServer and its ConnectionHandler
type: resource usage
versions: Python 3.7

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue31323>
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