Could rust become keg-only and rustup become a normal formula?

[ilyagr]

Output of brew config

HOMEBREW_VERSION: 4.4.19
ORIGIN: https://github.com/Homebrew/brew
HEAD: 23facb219df8615680636ef12103bb3313f44e2a
Last commit: 4 days ago
Branch: stable
Core tap JSON: 31 Jan 21:55 UTC
Core cask tap JSON: 31 Jan 21:55 UTC
HOMEBREW_PREFIX: /opt/homebrew
HOMEBREW_CASK_OPTS: []
HOMEBREW_DISPLAY: /private/tmp/com.apple.launchd.eVl4su3i9k/org.xquartz:0
HOMEBREW_EDITOR: vim
HOMEBREW_MAKE_JOBS: 12
HOMEBREW_NO_CLEANUP_FORMULAE: fish
Homebrew Ruby: 3.3.7 => /opt/homebrew/Library/Homebrew/vendor/portable-ruby/3.3.7/bin/ruby
CPU: dodeca-core 64-bit arm_blizzard_avalanche
Clang: 16.0.0 build 1600
Git: 2.48.1 => /opt/homebrew/bin/git
Curl: 8.7.1 => /usr/bin/curl
macOS: 14.7.3-arm64
CLT: 16.2.0.0.1.1733547573
Xcode: 16.2
Rosetta 2: false

Description of issue

I have two related problems:

• When I do brew install --HEAD fish, it installs rust as a dependency as expected. However, this means that running cargo then runs Homebrew's Rust instead of the one I've installed myself via Rustup. I have to remember to run brew unlink rust every time to fix it.
• It's inconvenient for me to use the rustup formula since it's keg-only and requires updating the PATH. I end up using manually installed rustup.

I don't know if this qualifies as a bug, but both problems would be solved if the rust formula became keg-only (since it seems most appropriately used as a built-time dependency for other formulas) and rustup became a normal formula (since it's more useful for a Rust developer who will manually call these binaries).

Is there any chance that this change could happen?

[SMillerDev]

I think that would complicate the use case where some new user thinks "I want to install rust" a lot.
Because after this change that would mean they don't have a usable rust version.

I'd be opposed to this change for that reason, it is simplifying the workflow of knowledgeable users and complicating the workflow of new ones.

[ilyagr]

I agree that this is an important consideration. I'm not sure what rustup's behavior is if no toolchain is installed. The formula does print a hint to run rustup toolchain install stable; I'm hoping that any sort of cargo command would also either install a toolchain or at least print a hint if there is no toolchain installed.

I'm also not sure the current situation is good for new users, since so many of Rust docs out there assume rustup-installed Rust. New users could get very confused if the instructions for contributing to a project require running cargo +nightly fmt, and that results in a confusing error because the cargo isn't actually called via rustup and doesn't understand +nightly.

[ilyagr]

I can also put it this way: when I'm telling people how to install Rust in, say, contributing guidelines for a project, I would currently say "please use the official installer and never, ever think of using a package manager". This is because many projects require cargo +nightly fmt, and some fully rely on nightly features. If I mentioned Homebrew at all, it would be to warn people that if something weird is going on, they should try brew unlink rust.

If this change was made, I could tell them "you can use the official installer, or just do brew install rustup if that's easier".

At least, that would be the goal; on second thought, somebody would have to check how well the resulting setup works (say, whether ~/.cargo/bin ends up in the path, or whether cargo install installs things somewhere else).

[SMillerDev]

Just curious, wouldn't it be easy for you to just add this to your shell init script:

export PATH="$(brew --prefix)/opt/rustup/bin:#PATH"