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

tests/test-sources/modules/performance/combine-plugins.nix

@@ -0,0 +1,105 @@
+{ pkgs, ... }:
+{
+  # Test basic functionality
+  default.module =
+    { config, ... }:
+    {
+      performance.combinePlugins.enable = true;
+      extraPlugins = with pkgs.vimPlugins; [
+        nvim-lspconfig
+        nvim-treesitter
+      ];
+      extraConfigLuaPost = ''
+        -- Plugins are loadable
+        require("lspconfig")
+        require("nvim-treesitter")
+
+        -- No separate plugin entries in nvim_list_runtime_paths
+        assert(not vim.iter(vim.api.nvim_list_runtime_paths()):any(function(entry)
+          return entry:find("treesitter") or entry:find("lspconfig")
+        end), "separate plugins are found in runtime")
+
+        -- Help tags are generated
+        assert(vim.fn.getcompletion("lspconfig", "help")[1], "no help tags for nvim-lspconfig")
+        assert(vim.fn.getcompletion("nvim-treesitter", "help")[1], "no help tags for nvim-treesitter")
+      '';
+      assertions = [
+        {
+          assertion = builtins.length config.finalPackage.packpathDirs.myNeovimPackages.start == 1;
+          message = "More than one plugin is defined in packpathDirs, expected one plugin pack.";
+        }
+      ];
+    };
+
+  # Test disabled option
+  disabled.module =
+    { config, ... }:
+    {
+      performance.combinePlugins.enable = false;
+      extraPlugins = with pkgs.vimPlugins; [
+        nvim-lspconfig
+        nvim-treesitter
+      ];
+      assertions = [
+        {
+          assertion = builtins.length config.finalPackage.packpathDirs.myNeovimPackages.start >= 2;
+          message = "Only one plugin is defined in packpathDirs, expected at least two.";
+        }
+      ];
+    };
+
+  # Test that plugin dependencies are handled
+  dependencies.module =
+    { config, ... }:
+    {
+      performance.combinePlugins.enable = true;
+      extraPlugins = with pkgs.vimPlugins; [
+        # Depends on nvim-cmp
+        cmp-dictionary
+        # Depends on telescope-nvim which itself depends on plenary-nvim
+        telescope-undo-nvim
+      ];
+      extraConfigLuaPost = ''
+        -- Plugins and its dependencies are loadable
+        require("cmp_dictionary")
+        require("cmp")
+        require("telescope-undo")
+        require("telescope")
+        require("plenary")
+      '';
+      assertions = [
+        {
+          assertion = builtins.length config.finalPackage.packpathDirs.myNeovimPackages.start == 1;
+          message = "More than one plugin is defined in packpathDirs.";
+        }
+      ];
+    };
+
+  # Test that pathsToLink option works
+  paths-to-link.module =
+    { config, ... }:
+    {
+      performance.combinePlugins = {
+        enable = true;
+        # fzf native library is in build directory
+        pathsToLink = [ "/build" ];
+      };
+      extraPlugins = [ pkgs.vimPlugins.telescope-fzf-native-nvim ];
+      extraConfigLuaPost = ''
+        -- Native library is in runtimepath
+        assert(
+          vim.api.nvim_get_runtime_file("build/libfzf.so", false)[1],
+          "build/libfzf.so is not found in runtimepath"
+        )
+
+        -- Native library is loadable
+        require("fzf_lib")
+      '';
+      assertions = [
+        {
+          assertion = builtins.length config.finalPackage.packpathDirs.myNeovimPackages.start == 1;
+          message = "More than one plugin is defined in packpathDirs.";
+        }
+      ];
+    };
+}