Follow CARGO_BUILD_TARGET env as target

[Vaider7]

Currently there's no way to override compilation target expect setting rust-analyzer.cargo.target option. That's a little bit annoying to modify config files every time you need LSP support for a target different from your host platform.

So I would like to propose that rust analyzer must follow CARGO_BUILD_TARGET if it is present as build target. I'm eager to implement it if the idea is approved

[ahirner]

I swear I saw rust-analyzer working (as helix LSP) some releases ago, with the right platform being analyzed. It doesn't work now.
E.g. this excludes #[cfg(target_os = "windows")] blocks.

CARGO_BUILD_TARGET="x86_64-pc-windows-msvc" hx

[ChayimFriedman2]

I don't like r-a to support Cargo environment variables. The proper way is rust-analyze.toml, which we already partially support.

Also FYI next time please open an issue, not a discussion.

[Vaider7]

Thx for reply!

Got you. Editing file works, but that's annoying. Changing environment variable much faster and feels like a proper way of doing such thing

[Vaider7]

Anyway, nothing stops to implement the priority of selecting: env var -> toml file -> default fallback

[ChayimFriedman2]

You would need to restart the editor anyway even if we support the environment variable.

[Vaider7]

That's fine I think. What is my case: I have a project with three different nix environment to cross compile for every major platform (Linux, Macos, Win). Every profile has its own CARGO_BUILD_TARGET, which allows to run cargo build and gets appropriate binary. Changing profile is one command in terminal, but to make rust-analyzer analyze source for Windows also requires manually editing r-a config (.helix/languages.toml for me). Yes, that's manageable with scripts on profile activation, but anyway env variable is just simpler and following CARGO_BUILD_TARGET makes sense because user already set target they want

[ChayimFriedman2]

It might be an interesting idea to have profiles for rust-analyzer.toml. Anyway your setup is not common and I still think we shouldn't respect Cargo's vars.