Switch Nix formatter to nixfmt

Author: lucperkins

.github/workflows/ci.yml

@@ -9,23 +9,30 @@ on:
 jobs:
   checks:
     name: Run all checks
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-24.04
     steps:
       - uses: actions/checkout@v5
       - uses: DeterminateSystems/determinate-nix-action@v3
       - uses: DeterminateSystems/flakehub-cache-action@main
+
+      - name: Check Nix formatting
+        run: git ls-files '*.nix' | xargs nix develop --command nixfmt --check
+
       - name: Install pnpm dependencies
         run: nix develop --command pnpm install
-      - name: Check formatting
-        run: nix develop --command pnpm run check-fmt
+
       - name: Lint
         run: nix develop --command pnpm run lint
+
       - name: Run test suite
         run: nix develop --command pnpm run test
+
       - name: Build
         run: nix develop --command pnpm run build
+
       - name: Check git status
         run: git status --porcelain=v1
+
       - name: Ensure no staged changes
         run: git diff --exit-code
 

flake.nix

@@ -23,23 +23,24 @@
         inputs.nixpkgs.lib.genAttrs supportedSystems (
           system:
           f {
+            inherit system;
             pkgs = import inputs.nixpkgs { inherit system; };
           }
         );
     in
     {
       inherit (inputs.flake-schemas) schemas;
 
-      formatter = forEachSupportedSystem ({ pkgs }: pkgs.nixfmt-rfc-style);
+      formatter = forEachSupportedSystem ({ pkgs, ... }: pkgs.nixfmt-rfc-style);
 
       devShells = forEachSupportedSystem (
-        { pkgs }:
+        { pkgs, system }:
         {
           default = pkgs.mkShellNoCC {
             packages = with pkgs; [
               nodejs_latest
               nodePackages_latest.pnpm
-              nixpkgs-fmt
+              self.formatter.${system}
             ];
           };
         }