add treefmt; switch to flake-parts

.github/workflows/nix-fmt-checks.yaml

@@ -18,4 +18,4 @@ jobs:
         uses: cachix/install-nix-action@v20
 
       - name: Run nix formatter tool
-        run: nix fmt . -- --check
+        run: nix fmt

default.nix

@@ -8,8 +8,6 @@ pkgs.python311.pkgs.buildPythonApplication {
   buildInputs = [ pkgs.makeWrapper ];
   nativeCheckInputs = [
     pkgs.python311.pkgs.pytest
-    pkgs.python311.pkgs.black
-    pkgs.ruff
     pkgs.glibcLocales
     pkgs.mypy
     # technically not test inputs, but we need it for development in PATH
@@ -17,17 +15,13 @@ pkgs.python311.pkgs.buildPythonApplication {
     pkgs.nix-prefetch-git
   ];
   checkPhase = ''
-    echo -e "\x1b[32m## run black\x1b[0m"
-    LC_ALL=en_US.utf-8 black --check . bin/nix-update
-    echo -e "\x1b[32m## run ruff\x1b[0m"
-    ruff . bin/nix-update
     echo -e "\x1b[32m## run mypy\x1b[0m"
     mypy --no-warn-unused-ignores --strict nix_update tests
   '';
   makeWrapperArgs = [
     "--prefix PATH"
     ":"
-    (pkgs.lib.makeBinPath [ pkgs.nixVersions.stable or pkgs.nix_2_4 pkgs.nixpkgs-fmt pkgs.nixpkgs-review pkgs.nix-prefetch-git ])
+    (pkgs.lib.makeBinPath [ pkgs.nixVersions.stable or pkgs.nix_2_4 pkgs.nixpkgs-review pkgs.nix-prefetch-git ])
   ];
   shellHook = ''
     # workaround because `python setup.py develop` breaks for me

flake.lock

@@ -1,40 +1,66 @@
 {
   "nodes": {
-    "flake-utils": {
+    "flake-parts": {
+      "inputs": {
+        "nixpkgs-lib": [
+          "nixpkgs"
+        ]
+      },
       "locked": {
-        "lastModified": 1678901627,
-        "narHash": "sha256-U02riOqrKKzwjsxc/400XnElV+UtPUQWpANPlyazjH0=",
-        "owner": "numtide",
-        "repo": "flake-utils",
-        "rev": "93a2b84fc4b70d9e089d029deacc3583435c2ed6",
+        "lastModified": 1683560683,
+        "narHash": "sha256-XAygPMN5Xnk/W2c1aW0jyEa6lfMDZWlQgiNtmHXytPc=",
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "rev": "006c75898cf814ef9497252b022e91c946ba8e17",
         "type": "github"
       },
       "original": {
-        "owner": "numtide",
-        "repo": "flake-utils",
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
         "type": "github"
       }
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1679262748,
-        "narHash": "sha256-DQCrrAFrkxijC6haUzOC5ZoFqpcv/tg2WxnyW3np1Cc=",
+        "lastModified": 1684525479,
+        "narHash": "sha256-Cq4jQE5OpB13nuEV3Ahm0UlpzeJBkb3PUz5pox4ih2E=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "60c1d71f2ba4c80178ec84523c2ca0801522e0a6",
+        "rev": "4a22f6f0a4b4354778f786425babce9a56f6b5d8",
         "type": "github"
       },
       "original": {
         "owner": "NixOS",
-        "ref": "nixos-unstable",
+        "ref": "nixpkgs-unstable",
         "repo": "nixpkgs",
         "type": "github"
       }
     },
     "root": {
       "inputs": {
-        "flake-utils": "flake-utils",
-        "nixpkgs": "nixpkgs"
+        "flake-parts": "flake-parts",
+        "nixpkgs": "nixpkgs",
+        "treefmt-nix": "treefmt-nix"
+      }
+    },
+    "treefmt-nix": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1684416994,
+        "narHash": "sha256-KkZ9diPRl3Y05TngWYs/QhZKnI/3tA3s+2Hhmei8FnE=",
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "rev": "42045102f90cfd23ca44ae4ef8362180fefcd7fd",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "type": "github"
       }
     }
   },

flake.nix

@@ -1,19 +1,22 @@
 {
   description = "Swiss-knife for updating nix packages.";
 
-  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
-  inputs.flake-utils.url = "github:numtide/flake-utils";
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+    flake-parts.url = "github:hercules-ci/flake-parts";
+    flake-parts.inputs.nixpkgs-lib.follows = "nixpkgs";
 
-  outputs = { self, nixpkgs, flake-utils }:
-    flake-utils.lib.eachDefaultSystem (system: {
-      formatter = nixpkgs.legacyPackages.${system}.nixpkgs-fmt;
+    treefmt-nix.url = "github:numtide/treefmt-nix";
+    treefmt-nix.inputs.nixpkgs.follows = "nixpkgs";
+  };
 
-      packages = {
-        default = self.packages.${system}.nix-update;
-
-        nix-update = nixpkgs.legacyPackages.${system}.callPackage self {
-          src = self;
-        };
+  outputs = inputs @ { flake-parts, ... }:
+    flake-parts.lib.mkFlake { inherit inputs; } ({ lib, ... }: {
+      imports = [ ./treefmt.nix ];
+      systems = lib.systems.flakeExposed;
+      perSystem = { config, pkgs, ... }: {
+        packages.nix-update = pkgs.callPackage ./. { };
+        packages.default = config.packages.nix-update;
       };
     });
 }

treefmt.nix

@@ -0,0 +1,45 @@
+{ inputs, ... }: {
+  imports = [
+    inputs.treefmt-nix.flakeModule
+  ];
+
+  perSystem = { pkgs, ... }: {
+    treefmt = {
+      # Used to find the project root
+      projectRootFile = "flake.lock";
+
+      programs.prettier.enable = true;
+
+      settings.formatter = {
+        nix = {
+          command = "sh";
+          options = [
+            "-eucx"
+            ''
+              # First deadnix
+              ${pkgs.lib.getExe pkgs.deadnix} --edit "$@"
+              # Then nixpkgs-fmt
+              ${pkgs.lib.getExe pkgs.nixpkgs-fmt} "$@"
+            ''
+            "--"
+          ];
+          includes = [ "*.nix" ];
+          excludes = [ "nix/sources.nix" ];
+        };
+
+        python = {
+          command = "sh";
+          options = [
+            "-eucx"
+            ''
+              ${pkgs.lib.getExe pkgs.ruff} --fix "$@"
+              ${pkgs.lib.getExe pkgs.python3.pkgs.black} "$@"
+            ''
+            "--" # this argument is ignored by bash
+          ];
+          includes = [ "*.py" ];
+        };
+      };
+    };
+  };
+}