Add rust analyzer configuration to discover Rust projects

[iinuwa]

Because we're using Meson as our build system (mostly), we don't get automatic discovery of Rust projects in rust-analyzer. rust-analyzer also does not share the same Cargo home as Meson, so everything gets compiled twice. It especially hurts when modifying lock files, since everything gets downloaded twice.

In my local .vscode/settings.json file, I have the following to make rust-analyzer work properly:

{
    "rust-analyzer.cargo.extraEnv": {
        "CARGO_HOME": "/home/isaiah/Development/rust/linux-webauthn-platform-api/build/cargo-home"
    },
    "rust-analyzer.runnables.extraEnv": {
        "CARGO_HOME": "/home/isaiah/Development/rust/linux-webauthn-platform-api/build/cargo-home"
    },
    "rust-analyzer.check.extraEnv": {
        "CARGO_HOME": "/home/isaiah/Development/rust/linux-webauthn-platform-api/build/cargo-home"
    },
    "rust-analyzer.server.extraEnv": {
        "CARGO_HOME": "/home/isaiah/Development/rust/linux-webauthn-platform-api/build/cargo-home"
    },
    "rust-analyzer.linkedProjects": [
        "credentialsd-common/Cargo.toml",
        "credentialsd-ui/Cargo.toml",
        "credentialsd/Cargo.toml",
    ],
}

I believe there are files you can put in a repository that will configure rust-analyzer manually. We should make one of those and at least put in the linkedProjects key in there. (I don't know if the CARGO_HOME will be useful if users don't use build for their build directory.)

[bjorn3]

For setting CARGO_HOME, using ${workspaceFolder} as placeholder for /home/isaiah/Development/rust/linux-webauthn-platform-api may work. I'm not completely sure if ${workspaceFolder} gets expanded in the extraEnv options though.

By the way just curious, but is there a reason why this repo doesn't use a cargo workspace? That way rust-analyzer.linkedProjects wouldn't be necessary and you did get a shared lockfile.

[iinuwa]

By the way just curious, but is there a reason why this repo doesn't use a cargo workspace? That way rust-analyzer.linkedProjects wouldn't be necessary and you did get a shared lockfile.

I haven't had the time to look into it. This project uses Meson for handling some of the needs outside of Rust/Cargo (GTK schema compilation, packaging and installation). I used build.rs for some of that before, but it's been easier to handle in Meson. Up until last week-ish, there was only one Rust project, so this didn't come up.

I haven't tried determining whether a workspace would cause issues with executing the build and install features via Meson/Ninja. If you're willing to work through it, I'd appreciate the help!

(see the related issue #95)

[iinuwa]

For setting CARGO_HOME, using ${workspaceFolder} as placeholder for /home/isaiah/Development/rust/linux-webauthn-platform-api may work. I'm not completely sure if ${workspaceFolder} gets expanded in the extraEnv options though.

Yeah, that may work, but I haven't tested. But I'd want to make the file IDE-agnostic, so I'd prefer to use the rust-project.json file instead if necessary.