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rustnixos

Compiler not installed when using configuration.nix

Problem

When trying to install a rust development environment utilizing the standard configuration.nix, the build chain is not fully installed or initialized, resulting in a linker error.

Steps to reproduce

environment.systemPackages = [
  rustc
  cargo
];
  • NOTE: This threw errors when trying to activate the configuration, so I had to modify the configuration as follows:
environment.systemPackages = with pkgs; [
    rustc
    cargo
  ];
  • Activate the configuration with: sudo nixos-rebuild switch

Now, you can create a project: cargo new rusttest

But when you try to build it: cargo build

I get the following error:

error: linker `cc` not found
  |
  = note: No such file or directory (os error 2)

error: could not compile `rusttest` due to previous error\

Shell Alternatives

I'm aware that utilizing the nix-shell (nix-shell -p rustc cargo) will result in a working environment, and for now, that's my workaround. However, I would like the standard configuration method to work.

Suggestions are appreciated.

Solution

  • While it is true that you can install compilers globally to environment.systemPackages, this is actually not the "standard configuration" for development tools. The recommended method is in fact nix-shell (or nix-develop for a flake-based environment), which was specifically designed to create cleanly separated development environments.

    For example, you can place a file named shell.nix in your project folder with this code:

    { pkgs ? import <nixpkgs> {}
}: pkgs.mkShell {
  nativeBuildInputs = with pkgs.buildPackages; [
    cargo
    rustc
  ];
}

    Then, you can run nix-shell with no arguments from your project directory to get a consistent Rust development environment each time, while still granting you the ability to use different tools and configurations for different projects without creating conflicts. Because it runs in user-space and has such reproducible results (including on non-NixOS hosts) it can even be safely checked into source control for others. Reproducibility is what Nix is all about!

    This will also install the default C compiler into your shell, which as of this writing is gcc-12.3.0 for nixos-23.11, but you can swap it out as needed for a different version, a cross-compiler, clang, etc.

    Don't worry about wasting disk space, either: as long as two nix-shells use the exact same version and configuration of the same tool, they will typically share the same package in /nix/store. If things change and packages go unused, the garbage collector will eventually remove them.