Nbclient waits indefinitely on killed subprocesses about nbclient

[MSeal]

Thanks for raising, sorry for not having a prompt response. I've got this issue queued to look into. It's likely the recent async changes is the root cause, though I too am not sure exactly where that's happening off-hand.

[davidbrochart]

@JoostvDoorn by default there is no timeout for cell execution. It tried your example and adding a timeout fixes the issue, e.g.:

client = NotebookClient(nb, kernel_name="python3", timeout=1)

raises a DeadKernelError("Kernel died") exception.
I'm wondering if we should not check regularly if the kernel is alive during the execution, not just if the execution timed out.

[JoostvDoorn]

@davidbrochart That's true, but that comes with the limitation that if the timeout time is exceeded but the kernel is still running okay it will give a CellTimeoutError.

[davidbrochart]

You're right, so we should regularly check for the kernel to be alive, independently of the timeout. I will open a PR.