Use selected syntax style for tracebacks and improve ANSI color codes support

[jsbautista]

Fixed traceback higlight, making use of the VerboseTB hack and adding a color homologation to expand the range of colors used by QtConsole
Before:

After:

related issues
spyder-ide/spyder#4891

[jsbautista]

@dalthviz

[dalthviz]

Thanks @jsbautista for the changes here. Left a comment regarding the change over the test. Let me know if you have questions!

[ccordoba12]

Thanks @jsbautista and @dalthviz for your work on this!

[ccordoba12]

A couple of comments about this change:

• The _tb_highlight_style attribute was added in IPython 8.15 (see Add hack to change traceback syntax highlighting ipython/ipython#14138). So, it's necessary a check that executes the new code for that or more recent versions, and leaves the previous one for older versions.
• It'd be a good idea to make _tb_highlight_style a public attribute of VerboseTB by submitting a PR to IPython. That would require an additional check here but it'd prevent they breaking us in the future.

[dalthviz]

The _tb_highlight_style attribute was added in IPython 8.15 (see ipython/ipython#14138). So, it's necessary a check that executes the new code for that or more recent versions, and leaves the previous one for older versions.

That's quite a good point! Thinking about that, and the fact that this way of customizing things is based on a hack, I would say that we should implement the validation using some sort of fallback approach rather than checking the package version (maybe at some point that hack is removed in favor of an actual public method for customization). Maybe we could check if the attribute is available and depending on that use it or fallback to the previous code that uses the magic?

[dalthviz]

I think something like this could work:

Suggested change

	f"from IPython.core.ultratb import VerboseTB;"
	"VerboseTB._tb_highlight_style = '{syntax_style}'",
	f"""
	from IPython.core.ultratb import VerboseTB
	try:
	VerboseTB._tb_highlight_style = '{syntax_style}'
	except AttributeError:
	get_ipython().run_line_magic('colors', '{colors}')
	""",

[ccordoba12]

This is very good approach, thanks @dalthviz! However, given that _tb_highlight_style is a private attribute of VerboseTB, I think it'd be a good idea to promote it to a public one in IPython and let Matthias know that we're using it here.

Otherwise, this functionality could break easily without us being aware of it (given that now there's a fallback in case that attribute is no longer available).

[dalthviz]

Created ipython/ipython#14464 to check your suggestion @ccordoba12

[ccordoba12]

Yep, thanks! I saw Matthias answer, so now please proceed to implement his suggestions there.

[dalthviz]

Note: The latest failing tests on linux and mac are unrelated with the work here, seems like a message about the debugger and frozen modules (the one that mentions things like using PYDEVD_DISABLE_FILE_VALIDATION=1 and -Xfrozen_modules=off) is being caught when doing the tests related with communications between frontend and kernel/kernel and frontend

Edit: Multiple CI reruns helps things pass on linux but probably something to check. Maybe that is the reason why the related tests have a high number of retries (flacky marked with 10 tries) 🤔

[dalthviz]

Thanks @jsbautista for your work here! Although ipython/ipython#14476 is still WIP I'm leaving this approved.

Just in case, do you have any further comments @ccordoba12? Should we wait until ipython/ipython#14476 gets merged to merge this or we could merge this regardless?

[ccordoba12]

Just in case, do you have any further comments @ccordoba12? Should we wait until ipython/ipython#14476 gets merged to merge this or we could merge this regardless?

Nop, I don't have more comments, so please merge it. If ipython/ipython#14476 goes in a different route, we can simply adapt the code here.