Add ExtensionLoader interface, use that on Config object (#12116)

packages/core/src/config/config.ts

@@ -154,6 +154,10 @@ import {
   DEFAULT_MEMORY_FILE_FILTERING_OPTIONS,
 } from './constants.js';
 import { debugLogger } from '../utils/debugLogger.js';
+import {
+  type ExtensionLoader,
+  SimpleExtensionLoader,
+} from '../utils/extensionLoader.js';
 
 export type { FileFilteringOptions };
 export {
@@ -248,7 +252,7 @@ export interface ConfigParameters {
   maxSessionTurns?: number;
   experimentalZedIntegration?: boolean;
   listExtensions?: boolean;
-  extensions?: GeminiCLIExtension[];
+  extensionLoader?: ExtensionLoader;
   enabledExtensions?: string[];
   blockedMcpServers?: Array<{ name: string; extensionName: string }>;
   noBrowser?: boolean;
@@ -337,7 +341,7 @@ export class Config {
   private inFallbackMode = false;
   private readonly maxSessionTurns: number;
   private readonly listExtensions: boolean;
-  private readonly _extensions: GeminiCLIExtension[];
+  private readonly _extensionLoader: ExtensionLoader;
   private readonly _enabledExtensions: string[];
   private readonly _blockedMcpServers: Array<{
     name: string;
@@ -440,7 +444,8 @@ export class Config {
     this.experimentalZedIntegration =
       params.experimentalZedIntegration ?? false;
     this.listExtensions = params.listExtensions ?? false;
-    this._extensions = params.extensions ?? [];
+    this._extensionLoader =
+      params.extensionLoader ?? new SimpleExtensionLoader([]);
     this._enabledExtensions = params.enabledExtensions ?? [];
     this._blockedMcpServers = params.blockedMcpServers ?? [];
     this.noBrowser = params.noBrowser ?? false;
@@ -885,7 +890,11 @@ export class Config {
   }
 
   getExtensions(): GeminiCLIExtension[] {
-    return this._extensions;
+    return this._extensionLoader.getExtensions();
+  }
+
+  getExtensionLoader(): ExtensionLoader {
+    return this._extensionLoader;
   }
 
   // The list of explicitly enabled extensions, if any were given, may contain