Ship a CLI for Pkg.jl

[MilesCranmer]

This PR adds a juliapkg binary shipped with juliaup that provides a shell CLI for Julia's Pkg manager. See JuliaLang/julia#59370 for the motivation and proposal.

I realized it's actually fairly simple to implement this in juliaup, because you get:

• Shared logic with the julialauncher.rs code
• Nice clap.rs help menu and shell completions
• Automatic Julia version management (+1.11, +release, etc.)
• No separate installation needed for users who already are installing with juliaup
• Consistent CLI experience with julia and juliaup commands

To try it out, run the following:

cargo install --git https://github.com/MilesCranmer/juliaup.git --branch jlpkg \
              --features juliapkg \
              --bin juliapkg

Here are some usage examples (again, this is just Pkg.jl REPLMode):

# Basic usage
juliapkg add DataFrames
juliapkg test
juliapkg instantiate

# With specific Julia version
juliapkg +1.11 add LinearAlgebra
juliapkg +release test

Here's the full clap.rs help menu:

> Julia package manager

Usage: juliapkg [OPTIONS] [COMMAND]
       juliapkg [OPTIONS] [COMMAND] [ARGS]...

    Julia options can be passed before the command:
        +<channel>         Select Julia channel (e.g., +1.10, +release)
        --project[=<path>] Set project directory
        [...]              Other Julia flags are also supported

Commands:
  add          Add packages to project
  build        Run the build script for packages
  compat       Edit compat entries in the current Project
  develop      Clone the full package repo locally for development [aliases: dev]
  free         Free pinned or developed packages
  generate     Generate files for packages
  gc           Garbage collect packages not used for a significant time
  instantiate  Download and install all artifacts in the manifest
  pin          Pin packages
  precompile   Precompile packages
  remove       Remove packages from project [aliases: rm]
  registry     Registry operations
  resolve      Resolve versions in the manifest
  status       Show project status [aliases: st]
  test         Run tests for packages
  update       Update packages in manifest [aliases: up]
  why          Explains why a package is in the dependency graph
  completions  Generate shell completion scripts
  help         Print this message or the help of the given subcommand(s)

Options:
  -h, --help  Print help

The implementation is quite simple since it borrows much of the logic from julialauncher.rs, and then forwards the user-provided commands to Pkg.REPLMode.pkgstr. This means there is minimal maintenance burden and it automatically stays in sync with Pkg.jl!

[MilesCranmer]

FYI - this file is 99% a git mv of the src/bin/julialauncher.rs. If you look in the git history you can see this, but for some reason, Github displays it as a new file.

[MilesCranmer]

@davidanthoff Any idea what these CI errors might be from? It seems it is not deterministic

[IanButterworth]

@fredrikekre might be a good reviewer from a product perspective here?

[cjdoris]

Cool! Maybe too early for bike shedding but I'm not personally a fan of the name jlpkg. Can I suggest either:

• Call it juliapkg.
• Make it all a subcommand of juliaup, such as juliaup pkg add or whatever.

I think I prefer the latter personally.

[MilesCranmer]

Yes please!

Note I also discuss the motivations in JuliaLang/julia#59370. I think the main benefit of putting jlpkg into juliaup is that you get to use the same code for managing the underlying Julia binary and channel, and don't need a separate install step. For example:

juliapkg +1.10 test

Is basically identical to julia +1.10 --startup-file=no --project=. -e 'using Pkg; pkg"test"'

This is equivalent at a low level, because this juliapkg call is fundamentally using the same code as src/bin/julialauncher.rs:

juliaup/src/bin/jlpkg.rs

Line 519 in f283646

let exit_code = juliaup::julia_launcher::run_julia_launcher(new_args, None)?;

P.S., we also get shell completions for every shell which is an added benefit of putting the command spec in clap:

> juliapkg completions --help
Generate shell completion scripts

Usage: juliapkg completions <SHELL>

Arguments:
  <SHELL>  [possible values: bash, elvish, fish, nushell, power-shell, zsh]

Options:
  -h, --help  Print help

[MilesCranmer]

I am a fan of juliapkg, I like that it fits the pattern of "julia update" => juliaup; "julia package" => juliapkg. Though I think juliaup pkg might be a tad long. Especially comparing to the other package managers. For example, rust is not rustup pkg add, even though rustup is the equivalent. In rust it is cargo add.

[MilesCranmer]

I renamed it to juliapkg for the time being, to match juliaup.

[MilesCranmer]

Btw, regarding

Make it all a subcommand of juliaup, such as juliaup pkg add or whatever.

I think the naming semantics aren't quite right: juliaup ~ julia update, therefore juliaup pkg add ~ julia update package add. Which is strange.

I prefer your juliapkg suggestion due of this, because juliapkg add ~ julia package add. Much nicer in my view

[IanButterworth]

juliapkg sounds good to me. Then perhaps we could recommend or even optionally prompt to link it to something shorter like pkg if the user wants.

[MilesCranmer]

I merged the latest changes from #1232 to this branch just FYI

[fredrikekre]

Shouldn't this just be an app in Pkg perhaps?

[MilesCranmer]

Shouldn't this just be an app in Pkg perhaps?

Maybe?

However, note that there are a few julia flag defaults that are inconvenient for a Pkg.jl session. The juliapkg binary here alters the default flags: --project=. --startup-file=no --threads=auto which is an advantage of having a layer of code sitting in front of julia.

The other drawback is a Pkg app would miss out on clap.rs-generated shell completions.

If Pkg apps eventually reach feature parity for these things, then a juliapkg CLI could just be a shell script that is aliased to use the app instead.

[MilesCranmer]

As the Pkg apps interface matures, one possibility could be for juliapkg to forward to julia (flags...) -m Pkg ... instead of julia (flags...) -e 'using Pkg; Pkg.REPLMode.pkgstr("...")'. At the moment a module invoked with -m can't adjust default flags like --project=., so I'm not sure how far a julia -m Pkg-by-default approach could go.

It also seems there might still be advantages to having a dedicated command installed by juliaup, since that would give shell completions (via clap.rs) and the ergonomics of a single entry point, even if the forwarding layer becomes thinner.