bleak: fix leaking of ensure_future() #1259
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As noted in the Python docs, a reference to the return value of `asyncio.ensure_future()` must be held in order to prevent it from being garbage collected before the task completes. This applies the recommended fix from the docs of holding the reference in a global set and then discarding the reference when the task completes. Also change `asyncio.ensure_future()` to `asyncio.create_task()` while we are touching this since the minimum supported Python version is now 3.7. Fixes: #1258
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cc: @bdraco |
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It might be safer to bind it to the scanner or client object as That will only work if its ok for the task to get GCed when the scanner/client goes out of scope (I think it is?) If we are sure the task will always eventually finish and release its references to the object than it probably doesn't matter. |
I don't think we ever want to have a task get GCed before completing, otherwise it could just stop in the middle of a coroutine without ever cancelling is which could lead to undefined/unexpected behavior. This type of fire-and-forget programming is a bit of an anti-pattern IMHO, so if people want to use it, I'm inclined to let them work out the details of how to cancel the task to avoid leaks if needed. |
As noted in the Python docs, a reference to the return value of
asyncio.ensure_future()must be held in order to prevent it from being garbage collected before the task completes.This applies the recommended fix from the docs of holding the reference in a global set and then discarding the reference when the task completes.
Also change
asyncio.ensure_future()toasyncio.create_task()while we are touching this since the minimum supported Python version is now 3.7.Fixes: #1258