nushell: allow installing plugins

[aidalgol]

Description

When the version of Nushell or any Nushell plugin changes, the plugin registry must be regenerated. This adds an option that takes a list of Nushell plugin derivations and recreates the plugin registry file (~/.config/nushell/plugin.msgpackz) on profile activation.

Thanks to @crabdancing for most of the work: nushell/nushell#12997 (reply in thread)

I believe this is worth adding a news entry even though it is only adding an option, because this has been a significant pain point for anyone using plugins with Nushell managed by home-manager.

Checklist

• Change is backwards compatible.

• Code formatted with ./format.

• Code tested through nix-shell --pure tests -A run.all or nix develop --ignore-environment .#all using Flakes.

• Test cases updated/added. See example.

• Commit messages are formatted like

  {component}: {description}
  
  {long description}
  

  See CONTRIBUTING for more information and recent commit messages for examples.

• If this PR adds a new module

  • Added myself as module maintainer. See example.

Maintainer CC

@Philipp-M @JoaquinTrinanes

[JoaquinTrinanes]

There are a couple of comments that need to be addressed before merging, but other than that it looks like it works nicely, thanks!

[JoaquinTrinanes]

Specifying a shebang is unnecessary if you're passing the program to nushell. Would it be easier to use the form nu --commands 'plugin add /nix/.../formats; plugin add /nix/.../polars'?

If not, this can be simplified with

pkgs.writeText "activateNushellPlugins.nu" ''
  # file contents in here
'';

[aidalgol]

Oh, of course. I had tried using --commands instead of generating and passing a script and got a command-not-found error, but your comment prompted me to try again, and it worked, so I must have been doing something else wrong. I think it looks much tidier now, thanks!

[aidalgol]

@JoaquinTrinanes Thanks for your feedback, and apologies for missing your existing PR that tried doing the same thing. 🤦

[JoaquinTrinanes]

Nice! No worries about the existing PR, it was stale for some months already 😅

Everything looks good now, I'd replace usages of pkgs.lib with just lib but the main issue is the top-level with lib. I might get rid of it someday 🙂

[rycee]

Thanks for the contribution @aidalgol and the review @JoaquinTrinanes! Merged to master now 🙂