AttributeError: 'NoneType' object has no attribute 'connect' at shutdown with polling transport

[ffteja]

I'm experiencing a bug (I guess) at shutdown when using the "polling" transport, not when using "websocket".

My setup:

• socketIO 5.12.1
• engineio 4.11.2
• aiohttp 3.11.13

My main function looks like this:

await sio.connect(host, auth=auth, socketio_path=url_path + "/api/v1/socket.io", retry=True, transports=["polling"])
await sio.wait()  # will reconnect to server if disconnected

So the code is blocked at the wait()

I'm calling await sio.shutdown() from my program, the expectation is the release of the wait() but that doesn't happen as intented:
Here is the traceback:

  File "/volumes/data/testclient/nexus_compute_agent/main.py", line 722, in main
    await sio.wait()  # will reconnect to server if disconnected
    ^^^^^^^^^^^^^^^^
  File "/volumes/data/testclient/nexus_compute_agent/pythonnca/lib/python3.11/site-packages/socketio/async_client.py", line 189, in wait
    await self.eio.wait()
  File "/volumes/data/testclient/nexus_compute_agent/pythonnca/lib/python3.11/site-packages/engineio/async_client.py", line 142, in wait
    await self.read_loop_task
  File "/volumes/data/testclient/nexus_compute_agent/pythonnca/lib/python3.11/site-packages/engineio/async_client.py", line 523, in _read_loop_polling
    r = await self._send_request(
        ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/volumes/data/testclient/nexus_compute_agent/pythonnca/lib/python3.11/site-packages/engineio/async_client.py", line 448, in _send_request
    return await http_method(
           ^^^^^^^^^^^^^^^^^^
  File "/volumes/data/testclient/nexus_compute_agent/pythonnca/lib/python3.11/site-packages/aiohttp/client.py", line 703, in _request
    conn = await self._connector.connect(
                 ^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'connect'

It looks like a TOCTOU issue where we are using a http client that is connected at the time of check but disconnected at the time of use due to awaits in the middle.

I'm not familiar with this part of code. What do you think?

[miguelgrinberg]

Yes, I can reproduce this here as well. Thanks for the report, I'll look into it.

miguelgrinberg/python-socketio#1441

[miguelgrinberg]

@ffteja I have implemented a fix in the python-socketio package. Could you install the main branch of that package from https://github.com/miguelgrinberg/python-socketio and confirm that the problem is gone in your tests? Thanks!