How to switch between Rust toolchains?

Question

rustup help toolchain lists the following sub-commands

SUBCOMMANDS:
    list         List installed toolchains
    install      Install or update a given toolchain
    uninstall    Uninstall a toolchain
    link         Create a custom toolchain by symlinking to a directory
    help         Prints this message or the help of the given subcommand(s)

I have the following toolchains installed

stable-x86_64-unknown-linux-gnu (default)
nightly-2019-09-05-x86_64-unknown-linux-gnu
nightly-x86_64-unknown-linux-gnu
master

I was trying to solve an issue for rust-clippy so I had to install the master toolchain. Even though stable is set as my default toolchain, my current toolchain is master and I would like to switch back to stable. How do I do it without uninstalling the master toolchain?

Is there no switch subcommand?

Solution 1

The rustup default stable command works well, but the easiest way is to keep a rust-toolchain file inside your project root folder. This is similar to a .nvm file for a NodeJS project.

rust-toolchain

nightly

or

stable

Solution 2

Use rustup default <toolchain> to change the default toolchain. You can use the full name (e.g. rustup default stable-x86_64-unknown-linux-gnu) or a short alias (e.g. rustup default stable).

rustup also has methods to override the default in a more scoped manner. See Overrides in the rustup book.

Solution 3

To toggle between nightly and stable configurations in your repo use:

rustup override set nightly

or:

rustup override set stable

Solution 4

rustup default stable should work. This will set stable as the default toolchain globally.

To set stable as the default toolchain for just one directory/ project, use rustup override set stable command instead. To unset it, use rustup override unset.

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Comments

[James Ray]

What if I just want to use switch toolchains temporarily, e.g. also to use cargo clippy, when my default toolchain is nightly?

[James Ray]

I found the answer: github.com/rust-lang/rustup#toolchain-override-shorthand. In the above scenario, I can do cargo +stable clippy

[Dylan Kerler]

This seems like the more conventional/robust approach so upvoted.

[n1nsa1d00]

Is there any minimal toolchain? I'm only interested in running a few commands such as cargo generate-lockfile and cargo tree