Garbage collection issue using python 3.8

[Beetix]

Hi,

I've tried the getting started example.

Unfortunately it doesn't seem to work due to a garbage collection issue using python 3.8. It works fine on python 3.7 (3.7.5 to be exact).

Here is the traceback:

An open stream was garbage collected prior to establishing network connection; call "stream.close()" explicitly.
Exception in callback _SelectorSocketTransport._call_connection_lost(None)
handle: <Handle _SelectorSocketTransport._call_connection_lost(None)>
Traceback (most recent call last):
  File "/usr/local/lib/python3.8/asyncio/events.py", line 81, in _run
    self._context.run(self._callback, *self._args)
  File "/usr/local/lib/python3.8/asyncio/selector_events.py", line 958, in _call_connection_lost
    super()._call_connection_lost(exc)
  File "/usr/local/lib/python3.8/asyncio/selector_events.py", line 716, in _call_connection_lost
    self._protocol.connection_lost(exc)
  File "/usr/local/lib/python3.8/site-packages/gmqtt/mqtt/protocol.py", line 194, in connection_lost
    self._connection.put_package((MQTTCommands.DISCONNECT, b''))
AttributeError: 'NoneType' object has no attribute 'put_package'
Traceback (most recent call last):
  File "./gmqtt_test.py", line 62, in <module>
    loop.run_until_complete(main(host))
  File "/usr/local/lib/python3.8/asyncio/base_events.py", line 608, in run_until_complete
    return future.result()
  File "./gmqtt_test.py", line 45, in main
    await client.connect(broker_host)
  File "/usr/local/lib/python3.8/site-packages/gmqtt/client.py", line 146, in connect
    await self._connection.auth(self._client_id, self._username, self._password, will_message=self._will_message,
  File "/usr/local/lib/python3.8/site-packages/gmqtt/mqtt/connection.py", line 50, in auth
    await self._protocol.send_auth_package(client_id, username, password, self._clean_session,
  File "/usr/local/lib/python3.8/site-packages/gmqtt/mqtt/protocol.py", line 87, in send_auth_package
    self.write_data(pkg)
  File "/usr/local/lib/python3.8/site-packages/gmqtt/mqtt/protocol.py", line 42, in write_data
    if not self._transport.is_closing():
AttributeError: 'NoneType' object has no attribute 'is_closing'

You can reproduce this by using the python 3.8-buster docker image:

host> docker run -it -v $SCRIPT_PATH:/gmqtt_getting_started.py python:3.8-buster /bin/bash
container> pip install gmqtt
container> /gmqtt_getting_started.py

Does anyone have an idea on how to fix this?

Thanks

[Lenka42]

@Beetix thanks for bringing this up.
Seems like the problem is caused by changes in asyncio StreamReader in 3.8.0
I will investigate it further

[Beetix]

Ok, great, thanks!

[Lenka42]

@Beetix try version gmqtt==0.4.5

Problem was caused by changes in asyncio.StreamReader, also this class is deprecated, so we need to get rid of this dependency later

[Beetix]

@Lenka42 I confirm it works. Thanks!