can't get barebones example building

[goosetherumfoodle]

I'm trying to just get this working with rust-hello and running into an flake does not provide attribute 'packages.x86_64-linux.default' error.

steps:
cargo init rust-hello
cd rust-hello
nix flake init -t github:yusdacra/nix-cargo-integration
echo "[package.metadata.nix]" >> Cargo.toml
echo "build = true" >> Cargo.toml
git add .
nix build

Error:

error: flake 'git+file:///<path>/rust-hello' does not provide attribute 'packages.x86_64-linux.default' or 'defaultPackage.x86_64-linux'

Adding systems = ["x86_64-linux"] to flake.nix doesn't change the error.

[yusdacra]

nix-cargo-integration doesn't provide any default packages. You need to use the outputs.defaults.package option to set a default package. Like so:

# flake.nix
{
  # ...
  outputs = inputs:
    inputs.nci.lib.makeOutputs {
      # ...
      config = common: {
        outputs.defaults = {
          package = "rust-hello";
        };
      };
      # ...
    };
}

[goosetherumfoodle]

Ah ok thanks.

After that step I'm running into the issue of not having a Cargo.lock. I see that nci is using dream2nix under the hood, and I'm getting the message (that I think is from dream2nix) about having an unresolved impurity. But nix flake show is only giving me the "rust-hello" package, not the "resolveImpure" package that dream2nix exposes. Do I have to do something additional to be able to run resolveImpure?

[yusdacra]

You just need to create a Cargo.lock, so just run cargo generate-lockfile for your project.