expose previewFeatures flag in a2a (#14550)

packages/a2a-server/src/config/config.ts

@@ -71,6 +71,7 @@ export async function loadConfig(
     ideMode: false,
     folderTrust: settings.folderTrust === true,
     extensionLoader,
+    previewFeatures: settings.general?.previewFeatures,
   };
 
   const fileService = new FileDiscoveryService(workspaceDir);

packages/a2a-server/src/config/settings.test.ts

@@ -0,0 +1,197 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
+import * as fs from 'node:fs';
+import * as path from 'node:path';
+import * as os from 'node:os';
+import { loadSettings, USER_SETTINGS_PATH } from './settings.js';
+
+const mocks = vi.hoisted(() => {
+  const suffix = Math.random().toString(36).slice(2);
+  return {
+    suffix,
+  };
+});
+
+vi.mock('node:os', async (importOriginal) => {
+  const actual = await importOriginal<typeof import('node:os')>();
+  const path = await import('node:path');
+  return {
+    ...actual,
+    homedir: () => path.join(actual.tmpdir(), `gemini-home-${mocks.suffix}`),
+  };
+});
+
+vi.mock('@google/gemini-cli-core', () => ({
+  GEMINI_DIR: '.gemini',
+  debugLogger: {
+    error: vi.fn(),
+  },
+  getErrorMessage: (error: unknown) => String(error),
+}));
+
+describe('loadSettings', () => {
+  const mockHomeDir = path.join(os.tmpdir(), `gemini-home-${mocks.suffix}`);
+  const mockWorkspaceDir = path.join(
+    os.tmpdir(),
+    `gemini-workspace-${mocks.suffix}`,
+  );
+  const mockGeminiHomeDir = path.join(mockHomeDir, '.gemini');
+  const mockGeminiWorkspaceDir = path.join(mockWorkspaceDir, '.gemini');
+
+  beforeEach(() => {
+    vi.clearAllMocks();
+    // Create the directories using the real fs
+    if (!fs.existsSync(mockGeminiHomeDir)) {
+      fs.mkdirSync(mockGeminiHomeDir, { recursive: true });
+    }
+    if (!fs.existsSync(mockGeminiWorkspaceDir)) {
+      fs.mkdirSync(mockGeminiWorkspaceDir, { recursive: true });
+    }
+
+    // Clean up settings files before each test
+    if (fs.existsSync(USER_SETTINGS_PATH)) {
+      fs.rmSync(USER_SETTINGS_PATH);
+    }
+    const workspaceSettingsPath = path.join(
+      mockGeminiWorkspaceDir,
+      'settings.json',
+    );
+    if (fs.existsSync(workspaceSettingsPath)) {
+      fs.rmSync(workspaceSettingsPath);
+    }
+  });
+
+  afterEach(() => {
+    try {
+      if (fs.existsSync(mockHomeDir)) {
+        fs.rmSync(mockHomeDir, { recursive: true, force: true });
+      }
+      if (fs.existsSync(mockWorkspaceDir)) {
+        fs.rmSync(mockWorkspaceDir, { recursive: true, force: true });
+      }
+    } catch (e) {
+      console.error('Failed to cleanup temp dirs', e);
+    }
+    vi.restoreAllMocks();
+  });
+
+  it('should load nested previewFeatures from user settings', () => {
+    const settings = {
+      general: {
+        previewFeatures: true,
+      },
+    };
+    fs.writeFileSync(USER_SETTINGS_PATH, JSON.stringify(settings));
+
+    const result = loadSettings(mockWorkspaceDir);
+    expect(result.general?.previewFeatures).toBe(true);
+  });
+
+  it('should load nested previewFeatures from workspace settings', () => {
+    const settings = {
+      general: {
+        previewFeatures: true,
+      },
+    };
+    const workspaceSettingsPath = path.join(
+      mockGeminiWorkspaceDir,
+      'settings.json',
+    );
+    fs.writeFileSync(workspaceSettingsPath, JSON.stringify(settings));
+
+    const result = loadSettings(mockWorkspaceDir);
+    expect(result.general?.previewFeatures).toBe(true);
+  });
+
+  it('should prioritize workspace settings over user settings', () => {
+    const userSettings = {
+      general: {
+        previewFeatures: false,
+      },
+    };
+    fs.writeFileSync(USER_SETTINGS_PATH, JSON.stringify(userSettings));
+
+    const workspaceSettings = {
+      general: {
+        previewFeatures: true,
+      },
+    };
+    const workspaceSettingsPath = path.join(
+      mockGeminiWorkspaceDir,
+      'settings.json',
+    );
+    fs.writeFileSync(workspaceSettingsPath, JSON.stringify(workspaceSettings));
+
+    const result = loadSettings(mockWorkspaceDir);
+    expect(result.general?.previewFeatures).toBe(true);
+  });
+
+  it('should handle missing previewFeatures', () => {
+    const settings = {
+      general: {},
+    };
+    fs.writeFileSync(USER_SETTINGS_PATH, JSON.stringify(settings));
+
+    const result = loadSettings(mockWorkspaceDir);
+    expect(result.general?.previewFeatures).toBeUndefined();
+  });
+
+  it('should load other top-level settings correctly', () => {
+    const settings = {
+      showMemoryUsage: true,
+      coreTools: ['tool1', 'tool2'],
+      mcpServers: {
+        server1: {
+          command: 'cmd',
+          args: ['arg'],
+        },
+      },
+      fileFiltering: {
+        respectGitIgnore: true,
+      },
+    };
+    fs.writeFileSync(USER_SETTINGS_PATH, JSON.stringify(settings));
+
+    const result = loadSettings(mockWorkspaceDir);
+    expect(result.showMemoryUsage).toBe(true);
+    expect(result.coreTools).toEqual(['tool1', 'tool2']);
+    expect(result.mcpServers).toHaveProperty('server1');
+    expect(result.fileFiltering?.respectGitIgnore).toBe(true);
+  });
+
+  it('should overwrite top-level settings from workspace (shallow merge)', () => {
+    const userSettings = {
+      showMemoryUsage: false,
+      fileFiltering: {
+        respectGitIgnore: true,
+        enableRecursiveFileSearch: true,
+      },
+    };
+    fs.writeFileSync(USER_SETTINGS_PATH, JSON.stringify(userSettings));
+
+    const workspaceSettings = {
+      showMemoryUsage: true,
+      fileFiltering: {
+        respectGitIgnore: false,
+      },
+    };
+    const workspaceSettingsPath = path.join(
+      mockGeminiWorkspaceDir,
+      'settings.json',
+    );
+    fs.writeFileSync(workspaceSettingsPath, JSON.stringify(workspaceSettings));
+
+    const result = loadSettings(mockWorkspaceDir);
+    // Primitive value overwritten
+    expect(result.showMemoryUsage).toBe(true);
+
+    // Object value completely replaced (shallow merge behavior)
+    expect(result.fileFiltering?.respectGitIgnore).toBe(false);
+    expect(result.fileFiltering?.enableRecursiveFileSearch).toBeUndefined();
+  });
+});

packages/a2a-server/src/config/settings.ts

@@ -20,7 +20,9 @@ import stripJsonComments from 'strip-json-comments';
 export const USER_SETTINGS_DIR = path.join(homedir(), GEMINI_DIR);
 export const USER_SETTINGS_PATH = path.join(USER_SETTINGS_DIR, 'settings.json');
 
-// Reconcile with https://github.com/google-gemini/gemini-cli/blob/b09bc6656080d4d12e1d06734aae2ec33af5c1ed/packages/cli/src/config/settings.ts#L53
+// TODO: Ensure full compatibility with V2 nested settings structure (settings.schema.json).
+// This involves updating the interface and implementing migration logic to support legacy V1 (flat) settings,
+// similar to how packages/cli/src/config/settings.ts handles it.
 export interface Settings {
   mcpServers?: Record<string, MCPServerConfig>;
   coreTools?: string[];
@@ -29,6 +31,9 @@ export interface Settings {
   showMemoryUsage?: boolean;
   checkpointing?: CheckpointingSettings;
   folderTrust?: boolean;
+  general?: {
+    previewFeatures?: boolean;
+  };
 
   // Git-aware file filtering settings
   fileFiltering?: {