Document how to install (and use) rustup with brew

[rami3l]

Problem you are trying to solve

AFAIK, the topic of installing and using rustup along with homebrew (brew) is not covered anywhere in the public docs, but it is also a common source of confusion among macOS users wanting to learn about Rust (#3458, ¹).

Solution you'd like

I am looking forward to some doc improvements in this respect.

Notes

No response

Footnotes

1. https://users.rust-lang.org/t/compile-failed-with-target-aarch64-linux-android/92439/14 ↩

[ChrisDenton]

Does homebrew maybe have documentation that can be linked to?

[rami3l]

@ChrisDenton

It's possible to add a def caveats block in rustup's homebrew manifest. For example, openjdk has the following:

For the system Java wrappers to find this JDK, symlink it with
    sudo ln -sfn $HOMEBREW_PREFIX/opt/openjdk/libexec/openjdk.jdk /Library/Java/JavaVirtualMachines/openjdk.jdk

However, I'm afraid that this still lacks discoverability.

Also, the generation of the rustup link to the original rustup-init binary should not be restricted to one package manager, so I think probably this is better documented in the user guide or somewhere similar...

[rami3l]

I think I will probably do the following as well:

• Add a similar message to brew's rustup-init package's caveats section suggesting that people should run rustup-init at least once instead of staring at the empty output of which rustup.
• If Mention brew install rustup-init in the user guide #3466 gets merged: add a link to the corresponding section of the user guide to the caveats.