IPykernel 6.9.0 generates error when Python errors are returned after execution

[ccordoba12]

This is very simple to reproduce in QtConsole. After executing something like this:

you'll see the following traceback in the terminal where it was started

Traceback (most recent call last):
  File "/home/carlos/miniconda3/envs/py310/lib/python3.10/site-packages/ipykernel/kernelbase.py", line 461, in dispatch_queue
    await self.process_one()
  File "/home/carlos/miniconda3/envs/py310/lib/python3.10/site-packages/ipykernel/kernelbase.py", line 450, in process_one
    await dispatch(*args)
TypeError: object NoneType can't be used in 'await' expression

I can't reproduce this in 6.8.0 or older versions and it's not related to the Python version I'm using (it was also reproduced in 3.8, as reported here).

I'd say this was introduced in PR #853, but I don't know how to fix it.

[blink1073]

cc @minrk

[minrk]

Creating a test env to see if I can track it down, but 90% sure something still has await self._abort_queues() which is no longer a coroutine. Adding async def back would fix that, but I'd like to take a minute to understand it first.

[ccordoba12]

No problem. Thanks for taking a look at this @minrk!

[minrk]

I was close! Right issue, wrong function. Fixed by #861