RUSTUP_TOOLCHAIN override prevents rustup overrides from being respected

[makspll]

As seen here:
https://github.com/rust-lang/rust-analyzer/blob/e265e3d5189513c42d037999d41a696369af9388/crates/flycheck/src/lib.rs#L408C1-L408C80

With the given settings.json:

    "rust-analyzer.check.invocationStrategy": "per_workspace",
    "rust-analyzer.check.invocationLocation": "workspace",
    "rust-analyzer.check.overrideCommand": [
        "cargo",
        "clippy",
        "--message-format=json"
    ],
    "rust-analyzer.linkedProjects": [
        "./crates/another_crate/Cargo.toml",
        "Cargo.toml"
    ],

I believe cargo clippy will be run from the root instead of the workspace location, meaning that rustup overrides are not respected, and hence checking fails for projects using different toolchains in each linked project.

Is there any work around?

[makspll]

Actually it looks like it's being run in the correct directory, BUT the toolchain is being overidden:

2024-03-23T15:01:44.709609Z  INFO project_model::build_scripts: Running build scripts in /<PATH>/ RA_RUSTC_WRAPPER="1" RUSTC_WRAPPER="<PATH>/server/rust-analyzer" RUSTUP_TOOLCHAIN="/<PATH>/.rustup/toolchains/stable-x86_64-unknown-linux-gnu" "/<PATH>/bin/cargo" "check" "--quiet" "--workspace" "--message-format=json" "--manifest-path" "/<PATH>/crates/crate/Cargo.toml" "--all-targets"

[makspll]

I've investigated further, the root issue can be seen here:

    "rust-analyzer.linkedProjects": [
        "./crates/bevy_api_gen/Cargo.toml",
        "Cargo.toml"
    ],
    "rust-analyzer.check.invocationStrategy": "per_workspace",
    "rust-analyzer.check.invocationLocation": "workspace",
    "rust-analyzer.check.overrideCommand": [
        "/home/makspll/git/bevy_mod_scripting/check.sh"
    ]

check.sh:

echo "invoked '$0' at '$PWD' with args: '$@', using toolchain '$(rustup show active-toolchain)'" >> /home/makspll/git/bevy_mod_scripting/log
cargo clippy --message-format=json

log:

invoked '/home/makspll/git/bevy_mod_scripting/check.sh' at '/home/makspll/git/bevy_mod_scripting' with args: '', using toolchain 'stable-x86_64-unknown-linux-gnu (environment override by RUSTUP_TOOLCHAIN)'
invoked '/home/makspll/git/bevy_mod_scripting/check.sh' at '/home/makspll/git/bevy_mod_scripting/crates/bevy_api_gen' with args: '', using toolchain 'stable-x86_64-unknown-linux-gnu (environment override by RUSTUP_TOOLCHAIN)'

You can see the rustup toolchain overrides are being overridden via the RUSTUP_TOOLCHAIN env variable, I am not sure why it's being set here

[Veykril]

See #16563, this is intentional. We want to make sure that we invoke the correct binaries for a given discovered sysroot of a workspace.