tree-wide: start using treefmt

3 files changed, 50 insertions, 3 deletions

diff --git a/flake.lock b/flake.lock
index e4f3dbe..36daa33 100644
--- a/flake.lock
+++ b/flake.lock
@@ -18,7 +18,28 @@
     },
     "root": {
       "inputs": {
-        "nixpkgs": "nixpkgs"
+        "nixpkgs": "nixpkgs",
+        "treefmt-nix": "treefmt-nix"
+      }
+    },
+    "treefmt-nix": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1719887753,
+        "narHash": "sha256-p0B2r98UtZzRDM5miGRafL4h7TwGRC4DII+XXHDHqek=",
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "rev": "bdb6355009562d8f9313d9460c0d3860f525bc6c",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "type": "github"
       }
     }
   },
diff --git a/flake.nix b/flake.nix
index fde7c88..37b0a77 100644
--- a/flake.nix
+++ b/flake.nix
@@ -8,10 +8,20 @@
 
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+
+    # this can be removed with `inputs.treefmt-nix.follows = ""`
+    treefmt-nix = {
+      url = "github:numtide/treefmt-nix";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
   };
 
   outputs =
-    { nixpkgs, ... }:
+    {
+      self,
+      nixpkgs,
+      treefmt-nix,
+    }:
     let
       inherit (nixpkgs) lib;
       systems = [
@@ -23,8 +33,13 @@
 
       forAllSystems = lib.genAttrs systems;
       nixpkgsFor = forAllSystems (system: nixpkgs.legacyPackages.${system});
+      treefmtFor = forAllSystems (system: treefmt-nix.lib.evalModule nixpkgsFor.${system} ./treefmt.nix);
     in
     {
+      checks = forAllSystems (system: {
+        treefmt = treefmtFor.${system}.config.build.check self;
+      });
+
       packages = forAllSystems (
         system:
         let
@@ -43,7 +58,7 @@
         pkgs' // { default = pkgs'.treefetch; }
       );
 
-      formatter = forAllSystems (system: nixpkgsFor.${system}.nixfmt-rfc-style);
+      formatter = forAllSystems (system: treefmtFor.${system}.config.build.wrapper);
 
       templates = import ./templates;
     };
diff --git a/treefmt.nix b/treefmt.nix
new file mode 100644
index 0000000..a02473d
--- /dev/null
+++ b/treefmt.nix
@@ -0,0 +1,11 @@
+{
+  projectRootFile = ".git/config";
+
+  # TODO: add actionlint
+  # https://github.com/numtide/treefmt-nix/pull/146
+  programs = {
+    deadnix.enable = true;
+    nixfmt-rfc-style.enable = true;
+    statix.enable = true;
+  };
+}