From a033432bb8dd42ca2b35a6cd3edc4fec8da44f48 Mon Sep 17 00:00:00 2001
From: Thomas Preisner <mail@tpreisner.de>
Date: Sat, 7 Dec 2024 12:55:51 +0100
Subject: [PATCH] flake.nix: Add and configure treefmt-nix for `nix fmt`

---
 flake.lock | 23 ++++++++++++++++++++++-
 flake.nix  | 17 +++++++++++++++--
 2 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/flake.lock b/flake.lock
index c12806c..43c3d18 100644
--- a/flake.lock
+++ b/flake.lock
@@ -116,7 +116,28 @@
       "inputs": {
         "flake-parts": "flake-parts",
         "git-hooks-nix": "git-hooks-nix",
-        "nixpkgs": "nixpkgs"
+        "nixpkgs": "nixpkgs",
+        "treefmt-nix": "treefmt-nix"
+      }
+    },
+    "treefmt-nix": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1733440889,
+        "narHash": "sha256-qKL3vjO+IXFQ0nTinFDqNq/sbbnnS5bMI1y0xX215fU=",
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "rev": "50862ba6a8a0255b87377b9d2d4565e96f29b410",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "type": "github"
       }
     }
   },
diff --git a/flake.nix b/flake.nix
index 89362b8..87b3dd8 100644
--- a/flake.nix
+++ b/flake.nix
@@ -5,6 +5,8 @@
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-24.11";
     flake-parts.url = "github:hercules-ci/flake-parts";
     flake-parts.inputs.nixpkgs-lib.follows = "nixpkgs";
+    treefmt-nix.url = "github:numtide/treefmt-nix";
+    treefmt-nix.inputs.nixpkgs.follows = "nixpkgs";
     git-hooks-nix.url = "github:cachix/git-hooks.nix";
     git-hooks-nix.inputs.nixpkgs.follows = "nixpkgs";
   };
@@ -21,6 +23,7 @@
         "aarch64-linux"
       ];
       imports = [
+        inputs.treefmt-nix.flakeModule
         inputs.git-hooks-nix.flakeModule
       ];
 
@@ -43,7 +46,7 @@
 
         devShells.default = pkgs.mkShell {
           packages = with pkgs; [
-            alejandra
+            self'.formatter.outPath # Add all formatters to environment
           ];
           shellHook = ''
             ${config.pre-commit.installationScript}
@@ -51,7 +54,17 @@
         };
 
         pre-commit.settings.hooks = {
-          alejandra.enable = true;
+          treefmt.enable = true;
+        };
+
+        treefmt = {
+          programs = {
+            alejandra.enable = true;
+          };
+          settings.global.excludes = [
+            ".envrc"
+            "*.sieve"
+          ];
         };
       };