Connection._on_close() not being called if Connection.closing is externally cancelled

[wbenny]

• Create a consumer connection
• Create a task T1 with await connection.closing
• When T1 gets externally cancelled (not by close() method, but e.g. when Ctrl+C is pressed during asyncio.run), the _on_close() method is never called.

I can call this method manually, like this:

async def _worker():
    try:
        await connection.closing
    except asyncio.CancelledError:
        connection._on_close()

But I don't think calling private methods should be "the best solution".

I thought I could get around this by calling await connection.close() (which results in calling _on_close()) in the CancelledError handler, however, there's a check for is_closed right at the top (and this check is also present in the __closer() callback.

    async def close(self, exc=asyncio.CancelledError()):
        if self.is_closed:
            return

... because is_closed returns true, the _on_close() will never get called.

My proposed solution would be to add_done_callback on the closing future, that calls _on_close, but this would also require to do a better check in the callbacks methods (instead of just is_closed).

I hope my explanation wasn't too much confusing, hit me back if you'd like me to clarify something.