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
                [email protected]
  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.