From 74b681d66552e24248a3c36524c932c4c796f985 Mon Sep 17 00:00:00 2001
From: Austin Horstman <khaneliman12@gmail.com>
Date: Mon, 7 Apr 2025 10:29:36 -0500
Subject: [PATCH] flake.nix: nixfmt -> treefmt

Instead of managing our own formatter file, we can leverage a tool
specifically tailored for formatting a repository and allowing
configuration to be passed to formatters.
---
 flake.lock | 23 ++++++++++++++++++++++-
 flake.nix  | 27 +++++++++++++++++++--------
 2 files changed, 41 insertions(+), 9 deletions(-)

diff --git a/flake.lock b/flake.lock
index 7cfad76cd..942b67b62 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": 1743748085,
+        "narHash": "sha256-uhjnlaVTWo5iD3LXics1rp9gaKgDRQj6660+gbUU3cE=",
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "rev": "815e4121d6a5d504c0f96e5be2dd7f871e4fd99d",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "type": "github"
       }
     }
   },
diff --git a/flake.nix b/flake.nix
index 96843fec5..29175de5e 100644
--- a/flake.nix
+++ b/flake.nix
@@ -1,9 +1,16 @@
 {
   description = "Home Manager for Nix";
 
-  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
 
-  outputs = { self, nixpkgs, ... }:
+    treefmt-nix = {
+      url = "github:numtide/treefmt-nix";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+  };
+
+  outputs = { self, nixpkgs, treefmt-nix, ... }:
     {
       nixosModules = rec {
         home-manager = ./nixos;
@@ -39,13 +46,17 @@
       lib = import ./lib { inherit (nixpkgs) lib; };
     } // (let
       forAllSystems = nixpkgs.lib.genAttrs nixpkgs.lib.systems.flakeExposed;
+
+      treefmtEval = forAllSystems (
+        system:
+        treefmt-nix.lib.evalModule nixpkgs.legacyPackages.${system} {
+          # Formatting configuration
+          programs = {
+            nixfmt.enable = true;
+          };
+        });
     in {
-      formatter = forAllSystems (system:
-        let pkgs = nixpkgs.legacyPackages.${system};
-        in pkgs.linkFarm "format" [{
-          name = "bin/format";
-          path = ./format;
-        }]);
+      formatter = forAllSystems  (system: treefmtEval.${system}.config.build.wrapper);
 
       packages = forAllSystems (system:
         let