asyncio coroutines not running through

break_asyncio_finally.py

import asyncio


RUNNING = set([])


async def coro(name, howlong=5, raise_exc=None):
    print('start', name)
    if raise_exc:
        raise raise_exc
    try:
        RUNNING.add(name)
        await asyncio.sleep(howlong)
        print('slept', name, howlong)
        RUNNING.remove(name)
    except BaseException as e:
        print(f'except {e.__class__.__name__} start', name)
        await asyncio.sleep(0.2)
        if name in RUNNING:
            RUNNING.remove(name)
        print(f'except {e.__class__.__name__} finished', name)
        raise

    return name


async def gather_or_wait(use_gather=True, raise_exc=None):
    loop = asyncio.get_running_loop()

    try:
        tasks = [
            loop.create_task(coro(1, howlong=1)),
            loop.create_task(coro(2, howlong=2)),
            loop.create_task(coro(3, howlong=3, raise_exc=raise_exc)),
        ]

        if use_gather:
            task = asyncio.gather(*tasks, return_exceptions=False)
            await task
        else:
            await asyncio.wait(tasks, return_when=asyncio.ALL_COMPLETED)
    except BaseException as e:
        print(f'{e.__class__.__name__} in gather_or_wait')
        for task in tasks:
            task.cancel()
        # Actually it doesn't matter if we use gather or wait here. With Approach 1 we still
        # don't run through and with Approach 3 we do.
        if use_gather:
            await asyncio.gather(*tasks, return_exceptions=True)
        else:
            await asyncio.wait(tasks, return_when=asyncio.ALL_COMPLETED)


def main():
    global RUNNING

    # Approach 1: doesn't work
    try:
        asyncio.run(gather_or_wait(use_gather=True, raise_exc=KeyboardInterrupt))
    except KeyboardInterrupt:
        print('KeyboardInterrupt in main')
    print('run gather: unfinished:', RUNNING)
    RUNNING = set([])

    print('\n------------------------------\n')

    # Approach 2: doesn't work
    loop = asyncio.new_event_loop()
    asyncio.set_event_loop(loop)
    task = loop.create_task(gather_or_wait(use_gather=True, raise_exc=KeyboardInterrupt))
    try:
        loop.run_until_complete(task)
    except KeyboardInterrupt:
        print('KeyboardInterrupt in main')
        task.cancel()
        loop.run_until_complete(task)
    loop.stop()
    loop.close()
    print('manual gather: unfinished:', RUNNING)
    RUNNING = set([])

    print('\n------------------------------\n')

    # Approach 3: works
    loop = asyncio.new_event_loop()
    asyncio.set_event_loop(loop)
    task = loop.create_task(gather_or_wait(use_gather=False, raise_exc=KeyboardInterrupt))
    try:
        loop.run_until_complete(task)
    except KeyboardInterrupt:
        print('KeyboardInterrupt in main')
        task.cancel()
        loop.run_until_complete(task)
    loop.stop()
    loop.close()
    print('manual wait: unfinished:', RUNNING)


if __name__ == "__main__":
    main()