Provide a better error message when uninstalling packages without dist-info/RECORD

[hroncok]

Fixes #8954

[hroncok]

Open question: What if INSTALLER says pip? In that case, the error would read:

ERROR: Cannot uninstall foobar 0.1, RECORD file not found. Hint: The package was installed by pip.

And that is a bit silly. Should INSTALLER with pip in it be treated the same way as missing INSTALLER?

[uranusjr]

The message should probably say something else if INSTALLER says pip. The pip value is also unreliable in practice since a lot of Conda packages incorrectly leave that file in their .dist-info directory (and they are unwilling to invest in effort fixing it because “everything works” from Conda’s point of view).

One possibility is to say declare the package outright broken and suggest re-installing it with pip install --force-reinstall --no-deps <name>==<version>.

[hroncok]

One possibility is to say declare the package outright broken and suggest re-installing it with pip install --force-reinstall --no-deps <name>==<version>.

That is getting rather complex and I am not sure I want to go that way.

---

If pip value is unreliable in practice, I think treating it like the case without INSTALLER is appropriate here. That would still be an improvement over the status quo. The suggestion can be added later.

[pfmoore]

I'm a little annoyed to think that we can't improve our users' experience by using a file that's explicitly designed to tell us when we manage an installation, just because some other project (conda in this case) is in violation of the standard.

@uranusjr's suggestion seems like the right approach to me (yes, it's a bit passive aggressive towards conda but 🤷). If pip does own the installation, then --force-reinstall --no-deps will fix the issue. So we should be giving that advice.

[hroncok]

Pushed a fixup commit for easier review (the intention is to squash it).

[hroncok]

Squashed.

[hroncok]

Approved and CI passed. Ready to be merged?

[encukou]

Is there anything I can do to help move this along?

[hroncok]

Thanks @pfmoore