Basilisk always upgrades Pip, which sometimes fails if conflicts with user's cache

[patkenneally]

Describe the bug
Basilisk always upgrades Pip. Recently a new version of pip was released (23.3.0) which conflicts with a user's cache ~/Library/Caches/pip/selfcheck/. The pip upgrade does not purge/remove cache items (using pip cache remove/purge) and so fails.

To reproduce
Steps to reproduce the behavior:

1. Assume installed pip version of 22.0.1 or less
2. Run conanfile.py which will automatically upgrade to latest (23.3 as of writing)
3. Upgrade will fail due to conflict with cached data in ~/Library/Caches/pip/selfcheck/

Expected behavior
A clear and concise description of what you expected to happen.

Screenshots
If applicable, add screenshots/plots to help explain your problem.

Desktop (please complete the following information):

• OS: Macos
• Version 13.6
• Python version 3.9.15

Additional context
Some additional rumination: the build system should be sufficiently opinionated so to ensure that the build configuration is robust and repeatable across systems e.g. pinning conan recipes, but not so much as to specify options not needed, or at least give the user an option to configure their system. In the case of pip, the project can specify a minimum required, and only then try and update. This doesn't fix the issue of deleting the local cache, but it does at least mean that it doesn't trigger the issue unnecessarily. I think a good solution here would be to check for a minimum version, and if an upgrade is required, run a strategic (if some strategy exists) pip cache purge/remove.

[schaubh]

As the pip cache is not held in the virtual environement, running pip cache purse/remove in our setup would not make sense?

[patkenneally]

True. I use a combination of pyenv and virtual environments. A large majority of the time I use pyenv. It gives me a bit more control over my python versions and builds. And managing the pip cache would work in the case of pyenv. For sure, virtual environments are good for everyday BSK development. I'll poke around further to see about a general solution.