Verbose diagnostics can be improved

[jolaf]

Even in verbose mode, mypy diagnostic output misses a lot of very useful things:

• Path to Python interpreter that is actually being used;
• Path to config file that is actually being used;
• Path to cache location that is actually being used.
• Actual path to files to check, gathered from MYPYPATH variable and config file.

Also for each file being checked, it would be useful to know:

• Full path to the file;
• Why mypy decided to check this particular file? Was it specified in the command line? By filename? By package name? By module name? Was it found in MYPYPATH? Was it imported by some other file? Maybe there are other ways?
• If module is imported, was it found in the current directory? In MYPYPATH? In dist-packages of the python interpreter?
• Is it a stub or an actual source file?

If file gets imported, but import fails, it would be extremely useful to know, why particularly.

• Is module really not found?
• Is module found, but stubs are not?
• Maybe stubs were found, but they're incorrect?

I'm having serious trouble debugging my mypy configuration in CI/CD system, for example at some points mypy stops seeing my stubs I've created for a 3rd-party library I use, and than at some points starts seeing them again. The cause is eluding me for many hours, and tracking it is really difficult without detailed logging.

I understand most of my questions are silly, but I'm really having trouble finding answers to them, and by the way, verbose/debug mode IS really a way to get answers to a lot of silly questions that nobody thought somebody would ever need, but at some points someone does, isn't it?

[msullivan]

There are a lot of good ideas here. Would you like to submit a PR implementing some of them?

[jolaf]

Hardly, for now.
I'm just starting working with mypy, writing my first stubs etc.
I know nothing about the mypy internal structure.

[jxcl]

Working on this issue

[jxcl]

The first section has a PR now, the other parts are harder to implement.

[SwagatSBhuyan]

Is this issue still open? Some of the later suggestions may not have been implemented due to complexity. I myself am really new to the mypy repository, but I'd like to help with the later implementations. It'd really be kind of you guys to maybe nudge me in the right direction @ilevkivskyi @akerami @jxcl @jolaf
Thanks!

[ilevkivskyi]

TBH I kind of lost track of what is the situation here. But other people can probably help.

[CarlFK]

There are 11 bullet points in the OP.
At PyCon 2023 sprint we determined some of them have been addressed.
It would be good if someone reviewed each and reported back which have been addressed and which are still outstanding.

[keshavt3]

I want to work on this.

[hauntsaninja]

Many of the things here have been addressed. Feel free to open PRs or issues for any other improvements you'd like.