dev: Add pre-commit-hooks.nix

dev/default.nix

@@ -1,9 +1,12 @@
 let
   flake = builtins.getFlake (toString ./.);
   fmc-lib = import ../lib.nix { inherit (flake.inputs.nixpkgs) lib; };
-  self = { inherit (flake) inputs; } // 
-    fmc-lib.evalFlakeModule
-      { inherit self; }
-      ./flake-module.nix;
+  self = {
+    inherit (flake) inputs;
+    outPath = ../.; # used by pre-commit module, etc
+  } //
+  fmc-lib.evalFlakeModule
+    { inherit self; }
+    ./flake-module.nix;
 in
   self.config.flake // { inherit (flake) inputs; }

dev/flake-module.nix

@@ -1,14 +1,28 @@
-flakeModuleArgs@{ config, lib, ... }:
+flakeModuleArgs@{ config, lib, inputs, ... }:
 
 {
   imports = [
+    inputs.pre-commit-hooks-nix.flakeModule
   ];
   systems = [ "x86_64-linux" "aarch64-darwin" ];
   perSystem = system: { config, self', inputs', pkgs, ... }: {
     _module.args.pkgs = inputs'.nixpkgs.legacyPackages;
+
     devShells.default = pkgs.mkShell {
-      nativeBuildInputs = [ pkgs.nixpkgs-fmt ];
+      nativeBuildInputs = [
+        pkgs.nixpkgs-fmt
+        pkgs.pre-commit
+      ];
+      shellHook = ''
+        ${config.pre-commit.installationScript}
+      '';
     };
+    pre-commit = {
+      inherit pkgs; # should make this default to the one it can get via follows
+      settings = {
+      };
+    };
+
     packages = {
       inherit (pkgs.nixosOptionsDoc { inherit (flakeModuleArgs) options; })
         optionsDocBook;

dev/flake.lock

@@ -1,12 +1,27 @@
 {
   "nodes": {
+    "flake-utils": {
+      "locked": {
+        "lastModified": 1619345332,
+        "narHash": "sha256-qHnQkEp1uklKTpx3MvKtY6xzgcqXDsz5nLilbbuL+3A=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "2ebf2558e5bf978c7fb8ea927dfaed8fefab2e28",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1652425756,
-        "narHash": "sha256-3+5j3ZU43oC5PxRfGDQ6xs5sYnypS5GBhVP6uf7PVGM=",
+        "lastModified": 1652734403,
+        "narHash": "sha256-pIp7mRuYQd4JY2Ih4QaDjKVFgu7f1yHRRAvpb/rU9Mg=",
         "owner": "hercules-ci",
         "repo": "nixpkgs",
-        "rev": "81a0a8be297a88f338ee0fd90c330cd94b4a55bd",
+        "rev": "0b02135d3bdf49f9154f60e7a4c9d54d5e0ee70d",
         "type": "github"
       },
       "original": {
@@ -16,9 +31,32 @@
         "type": "github"
       }
     },
+    "pre-commit-hooks-nix": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1638351750,
+        "narHash": "sha256-90OHC+11DIHD1QyMIPUuM3n6zjH5Mhc8RBZa0h8969A=",
+        "owner": "hercules-ci",
+        "repo": "pre-commit-hooks.nix",
+        "rev": "3bb289628867ac40fc9e7c514f8266b1ce8c0910",
+        "type": "github"
+      },
+      "original": {
+        "owner": "hercules-ci",
+        "ref": "flakeModule",
+        "repo": "pre-commit-hooks.nix",
+        "type": "github"
+      }
+    },
     "root": {
       "inputs": {
-        "nixpkgs": "nixpkgs"
+        "nixpkgs": "nixpkgs",
+        "pre-commit-hooks-nix": "pre-commit-hooks-nix"
       }
     }
   },

dev/flake.nix

@@ -5,6 +5,9 @@
     # Flakes don't give us a good way to depend on .., so we don't.
     # This has drastic consequences of course.
     nixpkgs.url = "github:hercules-ci/nixpkgs/functionTo-properly";
+
+    pre-commit-hooks-nix.url = "github:hercules-ci/pre-commit-hooks.nix/flakeModule";
+    pre-commit-hooks-nix.inputs.nixpkgs.follows = "nixpkgs";
   };
 
   outputs = { self, ... }: