Incorrect usage of asyncio.create_task() and asyncio.create_future()

[maxtruxa]

There are multiple instances of both asyncio.create_task() and asyncio.create_future() scattered throughout the library and the examples, where the returned task object is discarded. This is incorrect and can lead to (long-running) tasks disappearing mid-execution. This is explained in the documentation.

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Docs for asyncio.create_task():

Important: Save a reference to the result of this function, to avoid a task disappearing mid-execution. The event loop only keeps weak references to tasks. A task that isn’t referenced elsewhere may get garbage collected at any time, even before it’s done. For reliable “fire-and-forget” background tasks, gather them in a collection:

background_tasks = set()

for i in range(10):
    task = asyncio.create_task(some_coro(param=i))

    # Add task to the set. This creates a strong reference.
    background_tasks.add(task)

    # To prevent keeping references to finished tasks forever,
    # make each task remove its own reference from the set after
    # completion:
    task.add_done_callback(background_tasks.discard)

Docs for asyncio.ensure_future():

Important See also the create_task() function which is the preferred way for creating new Tasks.
Save a reference to the result of this function, to avoid a task disappearing mid-execution.

[bdraco]

python/cpython#88831

[bdraco]

home-assistant/core#87970