Function _on_completion

Lib/asyncio/tasks.py:503–514

(f)

    cur_task = current_task()

    def _on_completion(f):
        nonlocal counter
        counter -= 1
        if (counter <= 0 or
            return_when == FIRST_COMPLETED or
            return_when == FIRST_EXCEPTION and (not f.cancelled() and
                                                f.exception() is not None)):
            if timeout_handle is not None:
                timeout_handle.cancel()
            if not waiter.done():
                waiter.set_result(None)
        futures.future_discard_from_awaited_by(f, cur_task)

    for f in fs:
        f.add_done_callback(_on_completion)