Overlaying rust-bin

[NickHu]

Is it possible to globally overlay rustc, rustfmt, cargo, etc. for the dev shell and the build environment? I tried to use https://github.com/yusdacra/nix-cargo-integration/blob/master/docs/example_flake.nix#L39 but I wasn't very successful.

In particular, I am interested in using a version of rustc which has the wasm32-unknown-unknown target, e.g. from https://github.com/oxalica/rust-overlay.

[yusdacra]

If you are trying to add a target, you should use a rust-toolchain.toml file. In your case, this can look like this:

[toolchain]
channel = "nightly-2022-03-05" # or whatever channel you are using
targets = ["wasm32-unknown-unknown", "x86_64-unknown-linux-gnu"]

There isn't yet a way to directly override what toolchain nix-cargo-integration will use, as I haven't yet thought of a good way to expose this. Once #56 is merged, I can work on this more.

[NickHu]

I tried using a toolchain file but it didn't seem to have any effect. Maybe some interaction with cargo workspaces? I put the toolchain file in the root workspace directory next to Cargo.lock

[yusdacra]

That's interesting. Is it possible for you to share your project? I'd like to take a look at it.

[bobbbay]

@NickHu did you stage the rust-toolchain.toml in Git? Flakes copy files based on Git, so a new file has to be staged before it sees it.

[yavko]

In particular, I am interested in using a version of rustc which has the wasm32-unknown-unknown target, e.g. from oxalica/rust-overlay.

Same, whats the best way of doing this ATM?

[yusdacra]

right now nci.toolchains.mkBuild and nci.toolchains.mkShell attributes can be used to set toolchain also other than the automatic rust-overlay toolchain that pulls from the file (also can set `nci.toolchainConfig if you don't or can't use the file for whatever reason)