flakeify NUR

ci/update-nur.sh

@@ -19,6 +19,8 @@ git clone \
 
 nix run "${DIR}#" -- combine nur-combined
 
+nix flake lock --update-input nixpkgs
+
 if [[ -z "$(git diff --exit-code)" ]]; then
   echo "No changes to the output on this push; exiting."
 else

flake.nix

@@ -1,31 +1,49 @@
 {
   description = "Nix User Repository";
 
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
+    flake-parts = {
+      url = "github:hercules-ci/flake-parts";
+      inputs.nixpkgs-lib.follows = "nixpkgs";
+    };
+    treefmt-nix = {
+      url = "github:numtide/treefmt-nix";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+  };
+
   outputs =
-    { self }:
-    {
+    inputs@{ flake-parts, nixpkgs, ... }:
+    let
       overlay = final: prev: {
         nur = import ./default.nix {
           nurpkgs = prev;
           pkgs = prev;
         };
       };
-      nixosModules.nur =
-        { lib, pkgs, ... }:
+    in
+    flake-parts.lib.mkFlake { inherit inputs; } {
+      systems = builtins.filter (
+        system: builtins.hasAttr system nixpkgs.legacyPackages
+      ) nixpkgs.lib.platforms.all;
+      flake = {
+        overlays.default = overlay;
+      };
+      imports = [
+        inputs.treefmt-nix.flakeModule
+      ];
+      perSystem =
+        { system, ... }:
         {
-          options.nur = lib.mkOption {
-            type = lib.mkOptionType {
-              name = "nur";
-              description = "An instance of the Nix User repository";
-              check = builtins.isAttrs;
-            };
-            description = "Use this option to import packages from NUR";
-            default = import self {
-              nurpkgs = pkgs;
-              pkgs = pkgs;
-            };
-          };
+          treefmt.programs.nixfmt.enable = true;
+          # legacyPackages is used because nur is a package set
+          # This trick with the overlay is used because it allows NUR packages to depend on other NUR packages
+          legacyPackages =
+            (import nixpkgs {
+              inherit system;
+              overlays = [ overlay ];
+            }).nur;
         };
-      hmModules.nur = self.nixosModules.nur;
     };
 }