Memory leak on robust channel opening-closing

[defat]

Our application constantly opens and closes channels using robust connection. We detected memory leak, it can be reproduced using following snippet:

import asyncio

import aio_pika

CHANNELS_COUNT = 1000

async def main(amqp_uri):
    connection = await aio_pika.connect_robust(amqp_uri)
    print(len(connection.transport.connection.closing._callbacks))
    for _ in range(CHANNELS_COUNT):
        async with connection.channel():
            await asyncio.sleep(0)
    print(len(connection.transport.connection.closing._callbacks))

if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    parser.add_argument("--amqp_uri")
    args = parser.parse_args()
    asyncio.run(main(args.amqp_uri))

Not an expert in aio_pika, but seems leak can be fixed in abc.UnderlayConnection: callbacks should be removed on channel closing with .remove_done_callback, smth like:

    async def close(self, exc: Optional[ExceptionType] = None) -> Any:
        if self.close_callback.finished.is_set():
            return

        self.channel.closing.remove_done_callback(self.close_callback)
        self.channel.connection.closing.remove_done_callback(self.close_callback)

        result: Any = await self.channel.close(exc)
        await self.close_callback.wait()
        return result

[mosquito]

Excellent. Would you like create a PR

[mosquito]

@defat thank you for your investigation. It's really helped me.

[mosquito]

released in aio-pika==8.2.1