[New-bugs-announce] [issue34970] Protect all_tasks manipulation in asyncio.all_tasks()

[Andrew Svetlov]

New submission from Andrew Svetlov <andrew.svetlov at gmail.com>:

Traceback (most recent call last):
  File "C:\Users\max\AppData\Local\Programs\Python\Python37\lib\threading.py", line 917, in _bootstrap_inner
    self.run()
  File "D:\Proj\antwork\code\antwork_backend\server\data_handlers\order\playback_hd.py", line 147, in run
    send_to_ws(channel=self.room_name, data=json.loads(msg))
  File "D:\Proj\antwork\code\antwork_backend\server\data_exchange.py", line 26, in send_to_ws
    asyncio.run(channel_layer.group_send(channel, send_data))
  File "C:\Users\max\AppData\Local\Programs\Python\Python37\lib\asyncio\runners.py", line 46, in run
    _cancel_all_tasks(loop)
  File "C:\Users\max\AppData\Local\Programs\Python\Python37\lib\asyncio\runners.py", line 54, in _cancel_all_tasks
    to_cancel = tasks.all_tasks(loop)
  File "C:\Users\max\AppData\Local\Programs\Python\Python37\lib\asyncio\tasks.py", line 38, in all_tasks
    return {t for t in _all_tasks
  File "C:\Users\max\AppData\Local\Programs\Python\Python37\lib\asyncio\tasks.py", line 38, in <setcomp>
    return {t for t in _all_tasks
  File "C:\Users\max\AppData\Local\Programs\Python\Python37\lib\_weakrefset.py", line 61, in __iter__
    for itemref in self.data:
RuntimeError: Set changed size during iteration


https://github.com/python/cpython/commit/416c1ebd9896b394790dcb4f9f035b1a44ebe9ff#commitcomment-30887909

----------
components: asyncio
messages: 327632
nosy: asvetlov, ned.deily, yselivanov
priority: release blocker
severity: normal
status: open
title: Protect all_tasks manipulation in asyncio.all_tasks()
versions: Python 3.7, Python 3.8

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue34970>
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