neovim: use evalModule to typecheck plugins config (#488793)

pkgs/applications/editors/neovim/module.nix

@@ -0,0 +1,115 @@
+{ config, lib, ... }:
+let
+  /*
+    transform all plugins into an attrset
+    { optional = bool; plugin = package; }
+  */
+  normalizePlugins =
+    plugins:
+    let
+      defaultPlugin = {
+        plugin = null;
+        config = null;
+        optional = false;
+      };
+    in
+    map (x: defaultPlugin // (if (x ? plugin) then x else { plugin = x; })) plugins;
+
+  pluginWithConfigType =
+    with lib;
+    types.submodule {
+      options = {
+        config = mkOption {
+          type = types.nullOr types.lines;
+          description = "viml configuration associated with this plugin.";
+          default = null;
+          example = "set title";
+        };
+
+        optional = mkEnableOption "optional" // {
+          description = "Don't load automatically on startup (load with :packadd)";
+        };
+
+        plugin = mkOption {
+          type = types.package;
+          example = lib.literalExpression "vimPlugins.vim-fugitive";
+          description = "vim plugin";
+        };
+      };
+    };
+
+in
+{
+  options = {
+    plugins = lib.mkOption {
+      type = with lib.types; listOf (either package pluginWithConfigType);
+      default = [ ];
+      apply = normalizePlugins;
+      example = lib.literalExpression ''
+        with pkgs.vimPlugins; [
+          yankring
+          vim-nix
+          { plugin = vim-startify;
+            config = "let g:startify_change_to_vcs_root = 0";
+          }
+        ]
+      '';
+      description = ''
+        List of vim plugins to install optionally associated with
+        configuration to be placed in init.vim.
+      '';
+    };
+
+    runtimeDeps = lib.mkOption {
+      readOnly = true;
+      type = with lib.types; listOf package;
+      description = ''
+        List of derivations required at runtime
+      '';
+    };
+
+    pluginAdvisedLua = lib.mkOption {
+      readOnly = true;
+      type = lib.types.listOf lib.types.lines;
+      description = ''
+        Recommended configuration set in vim plugins via ".passthru.initLua".
+      '';
+    };
+
+    userPluginViml = lib.mkOption {
+      readOnly = true;
+      type = lib.types.listOf (lib.types.lines);
+      description = ''
+        The viml config set by the user.
+      '';
+    };
+
+  };
+
+  config =
+    let
+      pluginsNormalized = normalizePlugins config.plugins;
+    in
+    {
+      pluginAdvisedLua =
+        let
+          op =
+            acc: normalizedPlugin:
+            acc
+            ++ lib.optional (
+              normalizedPlugin.plugin.passthru ? initLua
+            ) normalizedPlugin.plugin.passthru.initLua;
+        in
+        lib.foldl' op [ ] pluginsNormalized;
+
+      runtimeDeps =
+        let
+          op = acc: normalizedPlugin: acc ++ normalizedPlugin.plugin.runtimeDeps or [ ];
+        in
+        lib.foldl' op [ ] pluginsNormalized;
+
+      userPluginViml = lib.foldl (
+        acc: p: if p.config != null then acc ++ [ p.config ] else acc
+      ) [ ] pluginsNormalized;
+    };
+}

pkgs/applications/editors/neovim/utils.nix

@@ -79,25 +79,30 @@ let
     plugins:
 
     let
+      neovimConfig =
+        structuredConfigure:
+        let
+          module = import ./module.nix;
+          # Generate init.vim configuration
+          cfg = (
+            lib.evalModules {
+              modules = [
+                module
+                structuredConfigure
+              ];
+            }
+          );
+        in
+        cfg.config;
+
+      checked_cfg = neovimConfig {
+        inherit plugins;
+      };
+
       pluginsNormalized = normalizePlugins plugins;
 
       vimPackage = normalizedPluginsToVimPackage pluginsNormalized;
 
-      userPluginViml = lib.foldl (
-        acc: p: if p.config != null then acc ++ [ p.config ] else acc
-      ) [ ] pluginsNormalized;
-
-      pluginAdvisedLua =
-        let
-          op =
-            acc: normalizedPlugin:
-            acc
-            ++ lib.optional (
-              normalizedPlugin.plugin.passthru ? initLua
-            ) normalizedPlugin.plugin.passthru.initLua;
-        in
-        lib.foldl' op [ ] pluginsNormalized;
-
       getDeps = attrname: map (plugin: plugin.${attrname} or (_: [ ]));
 
       requiredPlugins = vimUtils.requiredPluginsForPackage vimPackage;
@@ -108,10 +113,11 @@ let
       inherit pluginPython3Packages;
 
       # viml config set by the user along with the plugin
-      inherit userPluginViml;
-
-      # recommended configuration set in vim plugins ".passthru.initLua"
-      inherit pluginAdvisedLua;
+      inherit (checked_cfg)
+        userPluginViml
+        runtimeDeps
+        pluginAdvisedLua
+        ;
 
       # A Vim "package", see ':h packages'
       # You most likely want to use vimPackage as follows:
@@ -119,12 +125,6 @@ let
       #     finalPackdir = neovimUtils.packDir packpathDirs;
       inherit vimPackage;
 
-      runtimeDeps =
-        let
-          op = acc: normalizedPlugin: acc ++ normalizedPlugin.plugin.runtimeDeps or [ ];
-        in
-        lib.foldl' op [ ] pluginsNormalized;
-
     };
 
   /*