modules/performance: add an option to combine plugins to a single plugin pack

modules/default.nix

@@ -19,6 +19,7 @@
     ./lua-loader.nix
     ./opts.nix
     ./output.nix
+    ./performance.nix
     ./plugins.nix
   ];
 }

modules/performance.nix

@@ -0,0 +1,63 @@
+{ lib, ... }:
+let
+  inherit (lib) types;
+in
+{
+  options.performance = {
+    combinePlugins = {
+      enable = lib.mkEnableOption "combinePlugins" // {
+        description = ''
+          Whether to enable EXPERIMENTAL option to combine all plugins
+          into a single plugin pack. It can significantly reduce startup time,
+          but all your plugins must have unique filenames and doc tags.
+          Any collision will result in a build failure. To avoid collisions
+          you can add your plugin to the `standalonePlugins` option.
+          Only standard neovim runtime directories are linked to the combined plugin.
+          If some of your plugins contain important files outside of standard
+          directories, add these paths to `pathsToLink` option.
+        '';
+      };
+      pathsToLink = lib.mkOption {
+        type = with types; listOf str;
+        default = [ ];
+        example = [ "/data" ];
+        description = "List of paths to link into a combined plugin pack.";
+      };
+      standalonePlugins = lib.mkOption {
+        type = with types; listOf (either str package);
+        default = [ ];
+        example = [ "nvim-treesitter" ];
+        description = "List of plugins (names or packages) to exclude from plugin pack.";
+      };
+    };
+  };
+
+  config.performance = {
+    # Set option value with default priority so that values are appended by default
+    combinePlugins.pathsToLink = [
+      # :h rtp
+      "/autoload"
+      "/colors"
+      "/compiler"
+      "/doc"
+      "/ftplugin"
+      "/indent"
+      "/keymap"
+      "/lang"
+      "/lua"
+      "/pack"
+      "/parser"
+      "/plugin"
+      "/queries"
+      "/rplugin"
+      "/spell"
+      "/syntax"
+      "/tutor"
+      "/after"
+      # ftdetect
+      "/ftdetect"
+      # plenary.nvim
+      "/data/plenary/filetypes"
+    ];
+  };
+}

modules/top-level/files/default.nix

@@ -93,5 +93,8 @@ in
           ]
         ) extraFiles}
       '';
+
+      # Never combine user files with the rest of the plugins
+      performance.combinePlugins.standalonePlugins = [ config.filesPlugin ];
     };
 }

modules/top-level/output.nix

@@ -5,7 +5,10 @@
   helpers,
   ...
 }:
-with lib;
+let
+  inherit (lib) types mkOption;
+  inherit (lib) optional optionalString optionalAttrs;
+in
 {
   options = {
     viAlias = mkOption {
@@ -71,15 +74,106 @@ with lib;
 
   config =
     let
-      defaultPlugin = {
-        plugin = null;
-        config = "";
-        optional = false;
-      };
-
-      normalizedPlugins = map (
-        x: defaultPlugin // (if x ? plugin then x else { plugin = x; })
-      ) config.extraPlugins;
+      # Plugin normalization
+      normalize =
+        p:
+        let
+          defaultPlugin = {
+            plugin = null;
+            config = null;
+            optional = false;
+          };
+        in
+        defaultPlugin // (if p ? plugin then p else { plugin = p; });
+      normalizePluginList = plugins: map normalize plugins;
+
+      # Normalized plugin list
+      normalizedPlugins = normalizePluginList config.extraPlugins;
+
+      # Plugin list extended with dependencies
+      allPlugins =
+        let
+          pluginWithItsDeps =
+            p: [ p ] ++ builtins.concatMap pluginWithItsDeps (normalizePluginList p.plugin.dependencies or [ ]);
+        in
+        lib.unique (builtins.concatMap pluginWithItsDeps normalizedPlugins);
+
+      # Remove dependencies from all plugins in a list
+      removeDependencies = ps: map (p: p // { plugin = removeAttrs p.plugin [ "dependencies" ]; }) ps;
+
+      # Separated start and opt plugins
+      partitionedOptStartPlugins = builtins.partition (p: p.optional) allPlugins;
+      startPlugins = partitionedOptStartPlugins.wrong;
+      # Remove opt plugin dependencies since they are already available in start plugins
+      optPlugins = removeDependencies partitionedOptStartPlugins.right;
+
+      # Test if plugin shouldn't be included in plugin pack
+      isStandalone =
+        p:
+        builtins.elem p.plugin config.performance.combinePlugins.standalonePlugins
+        || builtins.elem (lib.getName p.plugin) config.performance.combinePlugins.standalonePlugins;
+
+      # Separated standalone and combined start plugins
+      partitionedStandaloneStartPlugins = builtins.partition isStandalone startPlugins;
+      toCombinePlugins = partitionedStandaloneStartPlugins.wrong;
+      # Remove standalone plugin dependencies since they are already available in start plugins
+      standaloneStartPlugins = removeDependencies partitionedStandaloneStartPlugins.right;
+
+      # Combine start plugins into a single pack
+      pluginPack =
+        let
+          # Every plugin has its own generated help tags (doc/tags)
+          # Remove them to avoid collisions, new help tags
+          # will be generate for the entire pack later on
+          overriddenPlugins = map (
+            plugin:
+            plugin.plugin.overrideAttrs (prev: {
+              nativeBuildInputs = lib.remove pkgs.vimUtils.vimGenDocHook prev.nativeBuildInputs or [ ];
+              configurePhase = ''
+                ${prev.configurePhase or ""}
+                rm -vf doc/tags'';
+            })
+          ) toCombinePlugins;
+
+          # Python3 dependencies
+          python3Dependencies =
+            let
+              deps = map (p: p.plugin.python3Dependencies or (_: [ ])) toCombinePlugins;
+            in
+            ps: builtins.concatMap (f: f ps) deps;
+
+          # Combined plugin
+          combinedPlugin = pkgs.vimUtils.toVimPlugin (
+            pkgs.buildEnv {
+              name = "plugin-pack";
+              paths = overriddenPlugins;
+              inherit (config.performance.combinePlugins) pathsToLink;
+              # Remove empty directories and activate vimGenDocHook
+              postBuild = ''
+                find $out -type d -empty -delete
+                runHook preFixup
+              '';
+              passthru = {
+                inherit python3Dependencies;
+              };
+            }
+          );
+
+          # Combined plugin configs
+          combinedConfig = builtins.concatStringsSep "\n" (
+            builtins.concatMap (x: lib.optional (x.config != null && x.config != "") x.config) toCombinePlugins
+          );
+        in
+        normalize {
+          plugin = combinedPlugin;
+          config = combinedConfig;
+        };
+
+      # Combined plugins
+      combinedPlugins = [ pluginPack ] ++ standaloneStartPlugins ++ optPlugins;
+
+      # Plugins to use in finalPackage
+      plugins = if config.performance.combinePlugins.enable then combinedPlugins else normalizedPlugins;
 
       neovimConfig = pkgs.neovimUtils.makeNeovimConfig (
         {
@@ -92,15 +186,15 @@ with lib;
             withNodeJs
             ;
           # inherit customRC;
-          plugins = normalizedPlugins;
+          inherit plugins;
         }
         # Necessary to make sure the runtime path is set properly in NixOS 22.05,
         # or more generally before the commit:
         # cda1f8ae468 - neovim: pass packpath via the wrapper
-        // optionalAttrs (functionArgs pkgs.neovimUtils.makeNeovimConfig ? configure) {
+        // optionalAttrs (lib.functionArgs pkgs.neovimUtils.makeNeovimConfig ? configure) {
           configure.packages = {
             nixvim = {
-              start = map (x: x.plugin) normalizedPlugins;
+              start = map (x: x.plugin) plugins;
               opt = [ ];
             };
           };
@@ -115,7 +209,9 @@ with lib;
       init = helpers.writeLua "init.lua" customRC;
 
       extraWrapperArgs = builtins.concatStringsSep " " (
-        (optional (config.extraPackages != [ ]) ''--prefix PATH : "${makeBinPath config.extraPackages}"'')
+        (optional (
+          config.extraPackages != [ ]
+        ) ''--prefix PATH : "${lib.makeBinPath config.extraPackages}"'')
         ++ (optional config.wrapRc ''--add-flags -u --add-flags "${init}"'')
       );
 

plugins/languages/treesitter/treesitter.nix

@@ -328,5 +328,10 @@ helpers.neovim-plugin.mkNeovimPlugin config {
       foldmethod = mkDefault "expr";
       foldexpr = mkDefault "nvim_treesitter#foldexpr()";
     };
+
+    # Since https://github.com/NixOS/nixpkgs/pull/321550 upstream queries are added
+    # to grammar plugins. Exclude nvim-treesitter itself from combining to avoid
+    # collisions with grammar's queries
+    performance.combinePlugins.standalonePlugins = [ cfg.package ];
   };
 }

plugins/telescope/default.nix

@@ -112,6 +112,9 @@ helpers.neovim-plugin.mkNeovimPlugin config {
         require('telescope').load_extension(extension)
       end
     '';
+
+    # planets picker requires files in data/memes/planets
+    performance.combinePlugins.pathsToLink = [ "/data/memes/planets" ];
   };
 
   settingsOptions = {

plugins/telescope/extensions/fzf-native.nix

@@ -52,4 +52,9 @@
       override_file_sorter = false;
       case_mode = "ignore_case";
     };
+
+    extraConfig = cfg: {
+      # Native library is in build/libfzf.so
+      performance.combinePlugins.pathsToLink = [ "/build" ];
+    };
   }

plugins/telescope/extensions/fzy-native.nix

@@ -38,4 +38,9 @@
       override_file_sorter = true;
       override_generic_sorter = false;
     };
+
+    extraConfig = cfg: {
+      # fzy-native itself is in deps directory
+      performance.combinePlugins.pathsToLink = [ "/deps/fzy-lua-native" ];
+    };
   }