Add dev flake and use nixCI

.envrc

@@ -0,0 +1 @@
+use flake ./dev

.github/workflows/ci.yaml

@@ -9,12 +9,14 @@ jobs:
   checks:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
-      - uses: cachix/install-nix-action@v18
+      - uses: actions/checkout@v3
+      - name: Install Nix
+        uses: DeterminateSystems/nix-installer-action@main
+      - uses: cachix/cachix-action@v12
         with:
-          extra_nix_config: |
-            experimental-features = nix-command flakes
-            access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
+          name: srid
+      - name: Build 🔨
+        run: nix run github:srid/nixci
       - name: Test example
         id: example
         run: |
@@ -28,8 +30,4 @@ jobs:
           cd $TEMP_DIR
           nix flake init -t $FLAKE
           nix develop --override-input mission-control path:${FLAKE} -c , fmt
-      - name: Flake checks 🧪
-        run: |
-          # Because 'nix flake check' is not system-aware
-          # See https://srid.ca/haskell-template/checks
-          nix run nixpkgs#sd 'systems = nixpkgs.lib.systems.flakeExposed' 'systems = [ "x86_64-linux" ]' flake.nix
+

.gitignore

@@ -0,0 +1 @@
+.direnv

dev/flake.nix

@@ -0,0 +1,39 @@
+{
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixpkgs-unstable";
+    flake-parts.url = "github:hercules-ci/flake-parts";
+    flake-root.url = "github:srid/flake-root";
+    mission-control.url = "github:Platonic-Systems/mission-control";
+    treefmt-nix.url = "github:numtide/treefmt-nix";
+  };
+  outputs = inputs@{ self, nixpkgs, flake-parts, ... }:
+    flake-parts.lib.mkFlake { inherit inputs; } {
+      systems = nixpkgs.lib.systems.flakeExposed;
+      imports = [
+        inputs.flake-root.flakeModule
+        inputs.mission-control.flakeModule
+        inputs.treefmt-nix.flakeModule
+      ];
+      perSystem = { pkgs, lib, config, ... }: {
+        treefmt = {
+          projectRootFile = "flake.nix";
+          programs = {
+            nixpkgs-fmt.enable = true;
+          };
+        };
+        mission-control.scripts = {
+          fmt = {
+            description = "Format all Nix files";
+            exec = config.treefmt.build.wrapper;
+          };
+        };
+        devShells.default = pkgs.mkShell {
+          # cf. https://zero-to-flakes.com/haskell-flake/devshell#composing-devshells
+          inputsFrom = [
+            config.mission-control.devShell
+            config.treefmt.build.devShell
+          ];
+        };
+      };
+    };
+}

flake.nix

@@ -1,10 +1,22 @@
 {
   description = "A `flake-parts` module for your Nix devshell scripts";
-  outputs = { self, ... }: {
+  outputs = { ... }: {
     flakeModule = ./nix/flake-module.nix;
     templates.default = {
       description = "Example flake using mission-control to provide scripts";
       path = builtins.path { path = ./example; filter = path: type: baseNameOf path == "flake.nix"; };
     };
+
+    # Config for https://github.com/srid/nixci
+    # To run this, `nix run github:srid/nixci`
+    nixci = let overrideInputs = { "mission-control" = ./.; }; in {
+      example = {
+        inherit overrideInputs;
+        dir = "./example";
+      };
+      dev = {
+        dir = "./dev";
+      };
+    };
   };
 }