Description

assignee = None
closed_at = None
created_at = <Date 2022-01-08.23:35:55.417>
labels = ['3.11', 'type-bug', '3.9', '3.10', 'expert-asyncio']
title = 'Task created by StreamReaderProtocol gets garbage collected.'
updated_at = <Date 2022-01-11.15:54:38.380>
user = 'https://github.com/simwr872'

activity = <Date 2022-01-11.15:54:38.380>
actor = 'AlexWaygood'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['asyncio']
creation = <Date 2022-01-08.23:35:55.417>
creator = 'simwr872'
dependencies = []
files = ['50552']
hgrepos = []
issue_num = 46309
keywords = ['patch']
message_count = 3.0
messages = ['410124', '410134', '410310']
nosy_count = 4.0
nosy_names = ['asvetlov', 'yselivanov', 'kumaraditya', 'simwr872']
pr_nums = ['30505']
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue46309'
versions = ['Python 3.9', 'Python 3.10', 'Python 3.11']

Activity

1. simwr872 commented on Jan 8, 2022

   

   simwr872mannequin

   on Jan 8, 2022

   MannequinAuthor

   More actions

   Documentation states that a reference must be kept when creating a task, https://docs.python.org/3/library/asyncio-task.html#asyncio.create_task.

   This is not done in StreamReaderProtocol, https://github.com/python/cpython/blob/main/Lib/asyncio/streams.py#L244.

   I've provided a simple example to force garbage collection of this task which results in Task was destroyed but it is pending!. Uncommenting the commented code of the example shows that the task is not destroyed when a reference is kept.

   Am I missing something or using the library incorrectly? I've followed the examples at https://docs.python.org/3/library/asyncio-stream.html#tcp-echo-server-using-streams.
2. simwr872

   added

   3.10 (EOL)end of lifeend of life

   topic-asyncio

   type-bugAn unexpected behavior, bug, or errorAn unexpected behavior, bug, or error

   on Jan 8, 2022
3. asvetlov commented on Jan 9, 2022

   

   asvetlov

   on Jan 9, 2022

   Contributor

   More actions

   Thanks for the bug report.

   Seems like your analysis is correct.

   Could you make a pull request which adds a task reference?
4. simwr872

   added

   3.7 (EOL)end of lifeend of life

   3.8 (EOL)end of lifeend of life

   3.9 (EOL)end of lifeend of life

   3.11only security fixesonly security fixes

   on Jan 11, 2022
5. 3 remaining items
6. AlexWaygood

   removed

   3.8 (EOL)end of lifeend of life

   3.7 (EOL)end of lifeend of life

   on Jan 11, 2022
7. ezio-melotti

   transferred this issue fromon Apr 10, 2022
8. ezio-melotti

   added this to asyncioon Jul 17, 2022
9. ezio-melotti

   moved this to Todo in asyncioon Jul 17, 2022
10. python273 commented on Aug 26, 2022

    

    python273

    on Aug 26, 2022

    Contributor

    More actions

    As a workaround, it's possible to keep the reference in a global variable

    background_tasks = set()
    def create_connection_task(*args, **kwargs):
        task = asyncio.create_task(handle_connection(*args, **kwargs))
        background_tasks.add(task)
        task.add_done_callback(background_tasks.discard)
    
    # asyncio.start_server(create_connection_task, ..)
11. python273

    added a commit that references this issue on Aug 26, 2022

    pythongh-90467: StreamReaderProtocol - add strong reference to create…

    91c8678
12. miss-islington

    added 2 commits that reference this issue on Aug 27, 2022

    pythongh-90467: StreamReaderProtocol - add strong reference to create…

    c98a665

    pythongh-90467: StreamReaderProtocol - add strong reference to create…

    63a903b
13. gvanrossum

    added a commit that references this issue on Aug 27, 2022

    gh-90467: StreamReaderProtocol - add strong reference to created task (…

    e860e52
14. pablogsal

    added a commit that references this issue on Aug 30, 2022

    gh-90467: StreamReaderProtocol - add strong reference to created task (…

    126ec34
15. miss-islington

    added a commit that references this issue on Sep 8, 2022

    gh-90467: StreamReaderProtocol - add strong reference to created task (…

    280130f
16. kumaraditya303

    closed this as completedon Sep 9, 2022
17. Repository owner moved this from Todo to Done in asyncioon Sep 9, 2022

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