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

packages/core/src/index.ts

@@ -66,6 +66,7 @@ export * from './utils/promptIdContext.js';
 export * from './utils/thoughtUtils.js';
 export * from './utils/debugLogger.js';
 export * from './utils/events.js';
+export * from './utils/extensionLoader.js';
 
 // Export services
 export * from './services/fileDiscoveryService.js';

packages/core/src/utils/extensionLoader.ts

@@ -0,0 +1,48 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { EventEmitter } from 'node:events';
+import type { GeminiCLIExtension } from '../config/config.js';
+
+export interface ExtensionLoader {
+  getExtensions(): GeminiCLIExtension[];
+
+  extensionEvents(): EventEmitter<ExtensionEvents>;
+}
+
+export interface ExtensionEvents {
+  extensionEnabled: ExtensionEnableEvent[];
+  extensionDisabled: ExtensionDisableEvent[];
+  extensionLoaded: ExtensionLoadEvent[];
+  extensionUnloaded: ExtensionUnloadEvent[];
+  extensionInstalled: ExtensionInstallEvent[];
+  extensionUninstalled: ExtensionUninstallEvent[];
+  extensionUpdated: ExtensionUpdateEvent[];
+}
+
+interface BaseExtensionEvent {
+  extension: GeminiCLIExtension;
+}
+export type ExtensionDisableEvent = BaseExtensionEvent;
+export type ExtensionEnableEvent = BaseExtensionEvent;
+export type ExtensionInstallEvent = BaseExtensionEvent;
+export type ExtensionLoadEvent = BaseExtensionEvent;
+export type ExtensionUnloadEvent = BaseExtensionEvent;
+export type ExtensionUninstallEvent = BaseExtensionEvent;
+export type ExtensionUpdateEvent = BaseExtensionEvent;
+
+export class SimpleExtensionLoader implements ExtensionLoader {
+  private _eventEmitter = new EventEmitter<ExtensionEvents>();
+  constructor(private readonly extensions: GeminiCLIExtension[]) {}
+
+  extensionEvents(): EventEmitter<ExtensionEvents> {
+    return this._eventEmitter;
+  }
+
+  getExtensions(): GeminiCLIExtension[] {
+    return this.extensions;
+  }
+}

packages/core/src/utils/memoryDiscovery.test.ts

@@ -16,6 +16,7 @@ import {
 import { FileDiscoveryService } from '../services/fileDiscoveryService.js';
 import { GEMINI_DIR } from './paths.js';
 import type { GeminiCLIExtension } from '../config/config.js';
+import { SimpleExtensionLoader } from './extensionLoader.js';
 
 vi.mock('os', async (importOriginal) => {
   const actualOs = await importOriginal<typeof os>();
@@ -88,7 +89,7 @@ describe('loadServerHierarchicalMemory', () => {
         [],
         false,
         new FileDiscoveryService(projectRoot),
-        [], // extensions
+        new SimpleExtensionLoader([]),
         false, // untrusted
       );
 
@@ -117,7 +118,7 @@ describe('loadServerHierarchicalMemory', () => {
           [],
           false,
           new FileDiscoveryService(projectRoot),
-          [], // extensions
+          new SimpleExtensionLoader([]),
           false, // untrusted
         );
 
@@ -133,7 +134,7 @@ describe('loadServerHierarchicalMemory', () => {
       [],
       false,
       new FileDiscoveryService(projectRoot),
-      [], // extensions
+      new SimpleExtensionLoader([]),
       DEFAULT_FOLDER_TRUST,
     );
 
@@ -155,7 +156,7 @@ describe('loadServerHierarchicalMemory', () => {
       [],
       false,
       new FileDiscoveryService(projectRoot),
-      [], // extensions
+      new SimpleExtensionLoader([]),
       DEFAULT_FOLDER_TRUST,
     );
 
@@ -182,7 +183,7 @@ default context content
       [],
       false,
       new FileDiscoveryService(projectRoot),
-      [], // extensions
+      new SimpleExtensionLoader([]),
       DEFAULT_FOLDER_TRUST,
     );
 
@@ -213,7 +214,7 @@ custom context content
       [],
       false,
       new FileDiscoveryService(projectRoot),
-      [], // extensions
+      new SimpleExtensionLoader([]),
       DEFAULT_FOLDER_TRUST,
     );
 
@@ -248,7 +249,7 @@ cwd context content
       [],
       false,
       new FileDiscoveryService(projectRoot),
-      [], // extensions
+      new SimpleExtensionLoader([]),
       DEFAULT_FOLDER_TRUST,
     );
 
@@ -280,7 +281,7 @@ Subdir custom memory
       [],
       false,
       new FileDiscoveryService(projectRoot),
-      [], // extensions
+      new SimpleExtensionLoader([]),
       DEFAULT_FOLDER_TRUST,
     );
 
@@ -312,7 +313,7 @@ Src directory memory
       [],
       false,
       new FileDiscoveryService(projectRoot),
-      [], // extensions
+      new SimpleExtensionLoader([]),
       DEFAULT_FOLDER_TRUST,
     );
 
@@ -356,7 +357,7 @@ Subdir memory
       [],
       false,
       new FileDiscoveryService(projectRoot),
-      [], // extensions
+      new SimpleExtensionLoader([]),
       DEFAULT_FOLDER_TRUST,
     );
 
@@ -409,7 +410,7 @@ Subdir memory
       [],
       false,
       new FileDiscoveryService(projectRoot),
-      [], // extensions
+      new SimpleExtensionLoader([]),
       DEFAULT_FOLDER_TRUST,
       'tree',
       {
@@ -445,7 +446,7 @@ My code memory
       [],
       true,
       new FileDiscoveryService(projectRoot),
-      [], // extensions
+      new SimpleExtensionLoader([]),
       DEFAULT_FOLDER_TRUST,
       'tree', // importFormat
       {
@@ -467,7 +468,7 @@ My code memory
       [],
       false,
       new FileDiscoveryService(projectRoot),
-      [], // extensions
+      new SimpleExtensionLoader([]),
       DEFAULT_FOLDER_TRUST,
     );
 
@@ -489,12 +490,12 @@ My code memory
       [],
       false,
       new FileDiscoveryService(projectRoot),
-      [
+      new SimpleExtensionLoader([
         {
           contextFiles: [extensionFilePath],
           isActive: true,
         } as GeminiCLIExtension,
-      ], // extensions
+      ]),
       DEFAULT_FOLDER_TRUST,
     );
 
@@ -521,7 +522,7 @@ Extension memory content
       [includedDir],
       false,
       new FileDiscoveryService(projectRoot),
-      [], // extensions
+      new SimpleExtensionLoader([]),
       DEFAULT_FOLDER_TRUST,
     );
 
@@ -556,7 +557,7 @@ included directory memory
       createdFiles.map((f) => path.dirname(f)),
       false,
       new FileDiscoveryService(projectRoot),
-      [], // extensions
+      new SimpleExtensionLoader([]),
       DEFAULT_FOLDER_TRUST,
     );
 
@@ -591,7 +592,7 @@ included directory memory
       [childDir, parentDir], // Deliberately include duplicates
       false,
       new FileDiscoveryService(projectRoot),
-      [], // extensions
+      new SimpleExtensionLoader([]),
       DEFAULT_FOLDER_TRUST,
     );
 

packages/core/src/utils/memoryDiscovery.ts

@@ -15,7 +15,7 @@ import { processImports } from './memoryImportProcessor.js';
 import type { FileFilteringOptions } from '../config/constants.js';
 import { DEFAULT_MEMORY_FILE_FILTERING_OPTIONS } from '../config/constants.js';
 import { GEMINI_DIR } from './paths.js';
-import type { GeminiCLIExtension } from '../config/config.js';
+import type { ExtensionLoader } from './extensionLoader.js';
 import { debugLogger } from './debugLogger.js';
 
 // Simple console logger, similar to the one previously in CLI's config.ts
@@ -338,7 +338,7 @@ export async function loadServerHierarchicalMemory(
   includeDirectoriesToReadGemini: readonly string[],
   debugMode: boolean,
   fileService: FileDiscoveryService,
-  extensions: GeminiCLIExtension[],
+  extensionLoader: ExtensionLoader,
   folderTrust: boolean,
   importFormat: 'flat' | 'tree' = 'tree',
   fileFilteringOptions?: FileFilteringOptions,
@@ -365,7 +365,8 @@ export async function loadServerHierarchicalMemory(
 
   // Add extension file paths separately since they may be conditionally enabled.
   filePaths.push(
-    ...extensions
+    ...extensionLoader
+      .getExtensions()
       .filter((ext) => ext.isActive)
       .flatMap((ext) => ext.contextFiles),
   );