Warning message on the first console that is open

[dalthviz]

Problem Description

A warning message appears on the first console that is launched when Spyder starts (at least on my Windows setup while checking the Spyder 6 beta2 rc0 installer - https://github.com/spyder-ide/spyder/actions/runs/9573557891):

C:\Users\dalth\AppData\Local\spyder-6\envs\spyder-runtime\Lib\threading.py:1045: UserWarning: Parent poll failed.  If the frontend dies,
                the kernel may be left running.  Please let us know
                about your system (bitness, Python, etc.) at
                ipython-dev@scipy.org
  self.run()

What steps reproduce the problem?

1. Launch Spyder

What is the expected output? What do you see instead?

Initial console launched when Spyder starts not showing any warning message

Versions

• Spyder version: 6.0.0b2.dev174 (standalone)
• Python version: 3.11.9 64-bit
• Qt version: 5.15.8
• PyQt5 version: 5.15.9
• Operating System: Windows-10-10.0.19045-SP0

[dalthviz]

Note: Seems like this could be related with #8205 (also an still open issue was created at IPython ipython/ipython#11727 +5 years ago) and the actual warning is still being generated over ipykernel: https://github.com/ipython/ipykernel/blob/d4a8703593cbe5d82bc955d68543dc623f5b4510/ipykernel/parentpoller.py#L113-L121

Seems like adding the warning text to the is_benign_error method over Spyder is not enough to ignore the warning and instead either a check needs to be added over QtConsole at the _handle_stream method from the FrontendWidget class or make the Spyder ShellWidget class reimplement that method so a check to ignore the warning a not show it can be added.

What do you think @ccordoba12 ?

[ccordoba12]

Is it possible to add some code to spyder-kernels to hide that warning?

If not, then I think the best solution is to override _handle_stream in ShellWidget until we have time to provide a fix upstream.

[dalthviz]

From a quick check maybe further customizing the outstream class could help?:

• https://github.com/spyder-ide/spyder-kernels/blob/67954aef9106fccd327f3c803f081076c4b8364b/spyder_kernels/console/start.py#L169-L170
• https://github.com/spyder-ide/spyder-kernels/blob/67954aef9106fccd327f3c803f081076c4b8364b/spyder_kernels/console/outstream.py

Particulary de _flush method (I think over there is where the stream message is formated and is being send):

• https://github.com/ipython/ipykernel/blob/d4a8703593cbe5d82bc955d68543dc623f5b4510/ipykernel/iostream.py#L663

[ccordoba12]

Ok, sounds good to me.