--prefix does not work with pip unistall

[JakobDev]

Description

Running this command

pip install --ignore-installed --no-deps --prefix /tmp/testpip requests

installs requests into /tmp/testpip.

But running this command:

pip uninstall --prefix /tmp/testpip requests

results in this error:

Usage:   
  pip uninstall [options] <package> ...
  pip uninstall [options] -r <requirements file> ...

no such option: --prefix

Expected behavior

pip should uninstall requests from the given prefix. If install allows this argument, uninstall should allow it too.

pip version

22.1.2

Python version

3.10

OS

Manjaro

How to Reproduce

See above

Output

No response

Code of Conduct

• I agree to follow the PSF Code of Conduct.

[pfmoore]

The problem here is that --prefix is simply one of a number of variants (the others being --root and --target) that try to influence "where pip installs things", but none of them actually fulfil the role of "specify the environment that pip is working on" - which is likely what the user actually wants.

Personally, I would prefer to see a global option, that tells pip what environment it should work on. That would affect all ways in which pip finds and manages installed packages, and could ultimately replace all of --target, --root, and --prefix.

So while I agree that the issue raise here is correct, I don't think we should address it by adding a --prefix flag to uninstall (to do so would be a lot harder than it seems at first, because pip uninstall X finds X in the "default environment", which doesn't recognise --prefix, and can't easily be made to). As a workaround for now, uninstalling can be handled by simply deleting the relevant files at the OS level.

See also #4575