modules: add gitsigns

lib/types.nix

@@ -129,7 +129,6 @@ let
 
       genConfig = mkOption {
         type = types.attrs;
-        readOnly = true;
         internal = true;
       };
     };

module-list.nix

@@ -15,6 +15,7 @@
   ./modules/plugins/style/neoformat.nix
   ./modules/plugins/navigation/telescope.nix
   ./modules/plugins/navigation/nvim-tree.nix
+  ./modules/plugins/gitsigns.nix
 
   ##################################################
   (pkgs.path + "/nixos/modules/misc/assertions.nix")

modules/plugins/gitsigns.nix

@@ -0,0 +1,38 @@
+{ config, lib, pkgs, ... }:
+
+let cfg = config.plugins.gitsigns; in
+
+{
+  options.plugins.gitsigns = with lib; {
+    enable = mkEnableOption "gitsigns-nvim";
+
+    package = mkPackageOption pkgs.vimPlugins "gitsigns-nvim" { };
+
+    settings = mkOption {
+      type = types.attrs;
+      default = { };
+    };
+
+    keymap.set = mkOption {
+      type = with types; listOf keymap;
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+    fn.gitsigns-nvim-on-attach = {
+      args = [ "bufnr" ];
+      settings = { bufnr }: {
+        vim.keymap.set = map (attrs: attrs // { buffer = bufnr; }) cfg.keymap.set;
+      };
+    };
+
+    plugin.gitsigns-nvim = {
+      name = "gitsigns";
+      varName = "gs";
+      package = cfg.package;
+      setupSettings = cfg.settings // {
+        on_attach = config.fn.gitsigns-nvim-on-attach.lambda;
+      };
+    };
+  };
+}