fix: use universal scope for fish_user_paths in fish shell integration

[bakotaco]

Summary

This PR addresses issue described in #1629. Currently the Fish shell setup script sets fish_user_paths as a global variable. This conflicts with the expected universal nature of fish_user_paths, leading to path assignments not persisting across sessions when using fish_add_path.

Fixes:

• fish_add_path is not persistent fish-shell/fish-shell#9819
• bug: fish path set-up breaks fish_add_path #1629

Other Information

This ensures that any paths added via fish_add_path are retained across all Fish shell sessions, aligning with the standard behavior of fish_add_path as outlined in its documentation.

[jthegedus]

Looks good to me, thanks!

[jthegedus]

And of course when I have the time to go through PRs for the first time this year GitHub "experiences issues". Will merge tomorrow. Cheers!

[jthegedus]

There seem to be some other fish issues, but we can deal with them separately 👍

[hyperupcall]

This MR is a breaking change in cases where a user uses asdf in a script, as shown by the failing tests. Because --universal persists the variable modification, there needs to be better isolation for the fish test as well, which wasn't done either.

[jthegedus]

This MR is a breaking change in cases where a user uses asdf in a script, as shown by the failing tests. Because --universal persists the variable modification, there needs to be better isolation for the fish test as well, which wasn't done either.

Yeah, I would like to get this fixed before performing a new release. Help welcome as my environment is currently unable to run fish without significant effort 😅

[bakotaco]

apologies, but after talking to @faho (long time fish contributor) I came to the conclusion this was actually an incorrect fix... I created a followup PR with a proper fix and explanation: #1709