Allow installing multiple applications at once

[sam-sw]

• I have added an entry to docs/changelog.md

Summary of changes

As a response to issue #971, the commands.install function is modified to take lists of package names/specs as arguments, and iterate through the lists, installing each application separately. The associated CLI functions and help strings are updated to reflect this. The commands.reinstall function is also modified to ensure it complies with the new argument requirements of commands.install. Two tests have been added (replicating test_install_easy_packages and test_install_tricky_packages, but doing multiple packages at once).

Test plan

Tested by manually running

pipx install pycowsay black

and also with the new unit tests.

Resolves #971

[sam-sw]

This is my take on responding to #971, happy to receive comments if a different approach may work better.

[chrysle]

This is an approach for creating a separate virtual environment for each of the packages.
Should an option be added to install all into the same one?

Also, I'd think one should also be able to remove and upgrade multiple packages. But that's out of the scope of this PR.

[sam-sw]

I agree with your comment about removing and upgrading multiple packages.

For installing multiple packages to the same virtual environment, would the current approach be to install one, and then inject the others, using the --include-apps option to ensure all applications are on the PATH? This is definitely more involved for users than a separate option on the install command, but then again the main reason for using pipx is to separate applications into unique virtual environments.

Personally I would lean away from having the extra install option, to keep things simple.

[uranusjr]

Should an option be added to install all into the same one?

This is already avaiable with --preinstall. It makes more sense to have --postinstall if needed.

[chrysle]

This is already avaiable with --preinstall.

Though this doesn't invite you to install multiple packages at once and doesn't make them globally available.

[gaborbernat]

Needs merge conflicts fixed.

[gaborbernat]

Seems stalled, we can reopen if you pick it up again.

[sam-sw]

Apologies for the delay, merged latest changes from the main branch now and fixed any conflicts etc.

[gaborbernat]

Seems you still need to fix some tests. 🤔

[sam-sw]

I've just re-ran nox locally and tests seem to be passing, except Python 3.9. But that also fails on the main branch as well?

[gaborbernat]

No failure on main https://github.com/pypa/pipx/actions/runs/7219455002

[gaborbernat]

Push a new commit to trigger a new CI run.

[sam-sw]

Looks like 3.8 and 3.9 fail because the strict=True argument in zip isn't implemented for those versions. Using zip this way was to satisfy the pre-commit check for code linting, what would you recommend?

[chrysle]

LGTM!

[gaborbernat]