fix: suppress duplicate extension warnings during startup (google-gemini#26208)

Author: cocosheng-g

packages/cli/src/config/config.ts

@@ -37,6 +37,7 @@ import {
   getAdminErrorMessage,
   isHeadlessMode,
   Config,
+  SimpleExtensionLoader,
   resolveToRealPath,
   applyAdminAllowlist,
   applyRequiredServers,
@@ -558,6 +559,7 @@ export interface LoadCliConfigOptions {
     disabled?: string[];
   };
   worktreeSettings?: WorktreeSettings;
+  skipExtensions?: boolean;
 }
 
 export async function loadCliConfig(
@@ -566,7 +568,7 @@ export async function loadCliConfig(
   argv: CliArgs,
   options: LoadCliConfigOptions = {},
 ): Promise<Config> {
-  const { cwd = process.cwd(), projectHooks } = options;
+  const { cwd = process.cwd(), projectHooks, skipExtensions = false } = options;
   const debugMode = isDebugMode(argv);
 
   const worktreeSettings =
@@ -641,21 +643,24 @@ export async function loadCliConfig(
     includeDirectories.push(...ideFolders);
   }
 
-  const extensionManager = new ExtensionManager({
-    settings,
-    requestConsent: requestConsentNonInteractive,
-    requestSetting: promptForSetting,
-    workspaceDir: cwd,
-    enabledExtensionOverrides: argv.extensions,
-    // eslint-disable-next-line @typescript-eslint/no-unsafe-type-assertion
-    eventEmitter: coreEvents as EventEmitter<ExtensionEvents>,
-    clientVersion: await getVersion(),
-  });
-  await extensionManager.loadExtensions();
+  let extensionManager: ExtensionManager | undefined;
+  if (!skipExtensions) {
+    extensionManager = new ExtensionManager({
+      settings,
+      requestConsent: requestConsentNonInteractive,
+      requestSetting: promptForSetting,
+      workspaceDir: cwd,
+      enabledExtensionOverrides: argv.extensions,
+      // eslint-disable-next-line @typescript-eslint/no-unsafe-type-assertion
+      eventEmitter: coreEvents as EventEmitter<ExtensionEvents>,
+      clientVersion: await getVersion(),
+    });
+    await extensionManager.loadExtensions();
+  }
 
   const extensionPlanSettings = extensionManager
-    .getExtensions()
-    .find((ext) => ext.isActive && ext.plan?.directory)?.plan;
+    ?.getExtensions()
+    ?.find((ext) => ext.isActive && ext.plan?.directory)?.plan;
 
   const experimentalJitContext = settings.experimental.jitContext ?? true;
 
@@ -673,6 +678,9 @@ export async function loadCliConfig(
   let fileCount = 0;
   let filePaths: string[] = [];
 
+  const finalExtensionLoader =
+    extensionManager ?? new SimpleExtensionLoader([]);
+
   if (!experimentalJitContext) {
     // Call the (now wrapper) loadHierarchicalGeminiMemory which calls the server's version
     const result = await loadServerHierarchicalMemory(
@@ -681,7 +689,7 @@ export async function loadCliConfig(
         ? includeDirectories
         : [],
       fileService,
-      extensionManager,
+      finalExtensionLoader,
       trustedFolder,
       memoryImportFormat,
       memoryFileFiltering,
@@ -1037,7 +1045,7 @@ export async function loadCliConfig(
     listSessions: argv.listSessions || false,
     deleteSession: argv.deleteSession,
     enabledExtensions: argv.extensions,
-    extensionLoader: extensionManager,
+    extensionLoader: finalExtensionLoader,
     extensionRegistryURI,
     enableExtensionReloading: settings.experimental?.extensionReloading,
     enableAgents: settings.experimental?.enableAgents,

packages/cli/src/config/skipExtensions.test.ts

@@ -0,0 +1,54 @@
+/**
+ * @license
+ * Copyright 2026 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { loadCliConfig, type CliArgs } from './config.js';
+import { ExtensionManager } from './extension-manager.js';
+import { createTestMergedSettings } from './settings.js';
+
+vi.mock('./extension-manager.js', () => ({
+  ExtensionManager: vi.fn().mockImplementation(() => ({
+    loadExtensions: vi.fn().mockResolvedValue([]),
+    getExtensions: vi.fn().mockReturnValue([]),
+  })),
+}));
+
+describe('loadCliConfig skipExtensions', () => {
+  const settings = createTestMergedSettings();
+  const argv = {
+    query: undefined,
+    model: undefined,
+    sandbox: undefined,
+    debug: undefined,
+    prompt: undefined,
+    promptInteractive: undefined,
+    yolo: undefined,
+    approvalMode: undefined,
+    policy: undefined,
+    adminPolicy: undefined,
+    allowedMcpServerNames: undefined,
+    allowedTools: undefined,
+    extensions: undefined,
+    listExtensions: undefined,
+    resume: undefined,
+    sessionId: undefined,
+    listSessions: undefined,
+  } as unknown as CliArgs;
+
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it('should load extensions by default', async () => {
+    await loadCliConfig(settings, 'session-id', argv);
+    expect(ExtensionManager).toHaveBeenCalled();
+  });
+
+  it('should skip extensions when skipExtensions is true', async () => {
+    await loadCliConfig(settings, 'session-id', argv, { skipExtensions: true });
+    expect(ExtensionManager).not.toHaveBeenCalled();
+  });
+});

packages/cli/src/gemini.tsx

@@ -409,6 +409,7 @@ export async function main() {
 
   const partialConfig = await loadCliConfig(settings.merged, sessionId, argv, {
     projectHooks: settings.workspace.settings.hooks,
+    skipExtensions: true,
   });
 
   adminControlsListner.setConfig(partialConfig);