nix: introduce treefmt-nix "nix fmt"

3 files changed, 35 insertions, 2 deletions

diff --git a/flake.lock b/flake.lock
index fa90b36..b6f0f31 100644
--- a/flake.lock
+++ b/flake.lock
@@ -59,7 +59,8 @@
       "inputs": {
         "flake-utils": "flake-utils",
         "home-manager": "home-manager",
-        "nixpkgs": "nixpkgs"
+        "nixpkgs": "nixpkgs",
+        "treefmt-nix": "treefmt-nix"
       }
     },
     "systems": {
@@ -76,6 +77,26 @@
         "repo": "default",
         "type": "github"
       }
+    },
+    "treefmt-nix": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1743748085,
+        "narHash": "sha256-uhjnlaVTWo5iD3LXics1rp9gaKgDRQj6660+gbUU3cE=",
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "rev": "815e4121d6a5d504c0f96e5be2dd7f871e4fd99d",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "type": "github"
+      }
     }
   },
   "root": "root",
diff --git a/flake.nix b/flake.nix
index 17260b1..54be09b 100644
--- a/flake.nix
+++ b/flake.nix
@@ -14,6 +14,11 @@
 
     flake-utils.url = "github:numtide/flake-utils";
 
+    treefmt-nix = {
+      url = "github:numtide/treefmt-nix";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+
     home-manager = {
       url = "github:nix-community/home-manager/master";
       inputs.nixpkgs.follows = "nixpkgs";
@@ -24,6 +29,7 @@
     {
       nixpkgs,
       flake-utils,
+      treefmt-nix,
       home-manager,
       ...
     }:
@@ -31,9 +37,10 @@
       system:
       let
         pkgs = import nixpkgs { inherit system; };
+        treefmt = treefmt-nix.lib.evalModule pkgs ./treefmt.nix;
       in
       {
-        formatter = pkgs.nixfmt-rfc-style;
+        formatter = treefmt.config.build.wrapper;
       }
     )
     // {
diff --git a/treefmt.nix b/treefmt.nix
new file mode 100644
index 0000000..972a362
--- /dev/null
+++ b/treefmt.nix
@@ -0,0 +1,5 @@
+{ pkgs, ... }:
+{
+  projectRootFile = "flake.nix";
+  programs.nixfmt.enable = true;
+}