New submission from Vincent Bernat :
asyncio will only keep weak references to alive tasks (in `_all_tasks`). If a
user does not keep a reference to a task and the task is not currently
executing or sleeping, the user may get "Task was destroyed but it is pending!".
I would suggest adding the following paragraph to `create_task()` documentation:
Python only keeps weak references to the scheduled tasks. To avoid the task
being destroyed by the garbage collector while still pending, a reference to it
should be kept until the task is done.
And maybe an example in case a user wants something "fire and forget"?
```python
running_tasks = set()
# [...]
task = asyncio.create_task(some_background_function())
running_tasks.add(task)
task.add_done_callback(lambda t: running_tasks.remove(t))
```
The same applies to ensure_future as it now uses create_task, so maybe a "See
create_task()".
--
assignee: docs@python
components: Documentation
messages: 397741
nosy: bernat, docs@python
priority: normal
severity: normal
status: open
title: asyncio.create_task() documentation should mention user needs to keep
reference to the task
type: enhancement
versions: Python 3.10, Python 3.11, Python 3.9
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<https://bugs.python.org/issue44665>
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