PR: Handle case when kernel fault file doesn't exist and show error with info explaining that no connection was possible (IPython Console)

[dalthviz]

Description of Changes

Seems like passing a .json file that doesn't correspond to a kernel connection file (like for example a .json that corresponds to a notebook server instance connection file) can cause the kernel fault file to not be initialized causing and error when trying to compute a message to show to the user. Also, add an error message to prevent keep showing the Connecting to kernel over the console infowidget when no connection was possible.

A preview:

Issue(s) Resolved

Fixes #22448

Affirmation

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[ccordoba12]

A couple of questions for @dalthviz:

• Connecting to external kernels is working as expected, right?
• What if instead of your approach, we parse the json file in the dialog, detect if it's valid and if not show a warning inside the dialog? I think that would make things simpler for users, but what do you think?

[ccordoba12]

On second thought, I think this is fine for a bugfix release @dalthviz.

I'm only leaving you a suggestion for the text you added.

[dalthviz]

Connecting to external kernels is working as expected, right?

From what I tested it seems like yes 👍

What if instead of your approach, we parse the json file in the dialog, detect if it's valid and if not show a warning inside the dialog? I think that would make things simpler for users, but what do you think?

Make sense but I would say that involves adding new logic and sounds more like an enhancement than a bug fix alone. Following your last comment, should an issue be created to track that enhancement idea (validation logic + feedback icon when selecting a kernel connection file)?

[ccordoba12]

Make sense but I would say that involves adding new logic and sounds more like an enhancement than a bug fix alone. Following your last comment, should an issue be created to track that enhancement idea (validation logic + feedback icon when selecting a kernel connection file)?

Yeah, I think that's a good idea. Please create one so that we don't forget to address that later.

[ccordoba12]

Thanks @dalthviz!

[ccordoba12]

@meeseeksdev please backport to 6.x