Ensure spawned libcoro tasks complete when cancelling - #1131
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If we are awaiting a libcoro task and are cancelled on the Python side, we currently just cancel the Python future leading to an asyncio warning when the C++ callback eventually fires to set a result. Furthermore, we might not end up waking C++ waiters if, for example, Python cancellation fails to successfully shut down a channel. To mitigate against this for most awaitables that bridge from Python into C++, introduce new utilities to shutdown channels, and await a C++ spawned task, handling cancellation, and optionally running some cleanup before raising the cancellation error.
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One suggestion, otherwise LGTM.
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If we are awaiting a libcoro task and are cancelled on the Python side, we currently just cancel the Python future leading to an asyncio warning when the C++ callback eventually fires to set a result. Furthermore, we might not end up waking C++ waiters if, for example, Python cancellation fails to successfully shut down a channel. To mitigate against this for most awaitables that bridge from Python into C++, introduce new utilities to shutdown channels, and await a C++ spawned task, handling cancellation, and optionally running some cleanup before raising the cancellation error. Backport of #1131 onto 26.08 Authors: - Lawrence Mitchell (https://github.com/wence-) Approvers: - Mads R. B. Kristensen (https://github.com/madsbk) - Tom Augspurger (https://github.com/TomAugspurger) - Bradley Dice (https://github.com/bdice) URL: #1133
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…aitables (#23293) To avoid cancellation in python leading to attempting to set a result on an already cancelled Future, use the new pattern introduced in rapidsai/rapidsmpf#1131 Authors: - Lawrence Mitchell (https://github.com/wence-) - Tom Augspurger (https://github.com/TomAugspurger) Approvers: - Tom Augspurger (https://github.com/TomAugspurger) - Vyas Ramasubramani (https://github.com/vyasr) URL: #23293
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If we are awaiting a libcoro task and are cancelled on the Python side, we currently just cancel the Python future leading to an asyncio warning when the C++ callback eventually fires to set a result. Furthermore, we might not end up waking C++ waiters if, for example, Python cancellation fails to successfully shut down a channel.
To mitigate against this for most awaitables that bridge from Python into C++, introduce new utilities to shutdown channels, and await a C++ spawned task, handling cancellation, and optionally running some cleanup before raising the cancellation error.