feat: Multi-Directory Workspace Support (part1: add --include-directories option) (#4605)

Co-authored-by: Allen Hutchison <adh@google.com>

packages/core/src/config/config.test.ts

@@ -19,6 +19,18 @@ import {
 import { GeminiClient } from '../core/client.js';
 import { GitService } from '../services/gitService.js';
 
+vi.mock('fs', async (importOriginal) => {
+  const actual = await importOriginal<typeof import('fs')>();
+  return {
+    ...actual,
+    existsSync: vi.fn().mockReturnValue(true),
+    statSync: vi.fn().mockReturnValue({
+      isDirectory: vi.fn().mockReturnValue(true),
+    }),
+    realpathSync: vi.fn((path) => path),
+  };
+});
+
 // Mock dependencies that might be called during Config construction or createServerConfig
 vi.mock('../tools/tool-registry', () => {
   const ToolRegistryMock = vi.fn();
@@ -219,6 +231,23 @@ describe('Server Config (config.ts)', () => {
     expect(config.getFileFilteringRespectGitIgnore()).toBe(false);
   });
 
+  it('should initialize WorkspaceContext with includeDirectories', () => {
+    const includeDirectories = ['/path/to/dir1', '/path/to/dir2'];
+    const paramsWithIncludeDirs: ConfigParameters = {
+      ...baseParams,
+      includeDirectories,
+    };
+    const config = new Config(paramsWithIncludeDirs);
+    const workspaceContext = config.getWorkspaceContext();
+    const directories = workspaceContext.getDirectories();
+
+    // Should include the target directory plus the included directories
+    expect(directories).toHaveLength(3);
+    expect(directories).toContain(path.resolve(baseParams.targetDir));
+    expect(directories).toContain('/path/to/dir1');
+    expect(directories).toContain('/path/to/dir2');
+  });
+
   it('Config constructor should set telemetry to true when provided as true', () => {
     const paramsWithTelemetry: ConfigParameters = {
       ...baseParams,

packages/core/src/config/config.ts

@@ -50,6 +50,7 @@ import { IdeClient } from '../ide/ide-client.js';
 
 // Re-export OAuth config type
 export type { MCPOAuthConfig };
+import { WorkspaceContext } from '../utils/workspaceContext.js';
 
 export enum ApprovalMode {
   DEFAULT = 'default',
@@ -172,6 +173,7 @@ export interface ConfigParameters {
   proxy?: string;
   cwd: string;
   fileDiscoveryService?: FileDiscoveryService;
+  includeDirectories?: string[];
   bugCommand?: BugCommandSettings;
   model: string;
   extensionContextFilePaths?: string[];
@@ -194,6 +196,7 @@ export class Config {
   private readonly embeddingModel: string;
   private readonly sandbox: SandboxConfig | undefined;
   private readonly targetDir: string;
+  private readonly workspaceContext: WorkspaceContext;
   private readonly debugMode: boolean;
   private readonly question: string | undefined;
   private readonly fullContext: boolean;
@@ -248,6 +251,10 @@ export class Config {
       params.embeddingModel ?? DEFAULT_GEMINI_EMBEDDING_MODEL;
     this.sandbox = params.sandbox;
     this.targetDir = path.resolve(params.targetDir);
+    this.workspaceContext = new WorkspaceContext(
+      this.targetDir,
+      params.includeDirectories ?? [],
+    );
     this.debugMode = params.debugMode;
     this.question = params.question;
     this.fullContext = params.fullContext ?? false;
@@ -392,6 +399,10 @@ export class Config {
     return this.targetDir;
   }
 
+  getWorkspaceContext(): WorkspaceContext {
+    return this.workspaceContext;
+  }
+
   getToolRegistry(): Promise<ToolRegistry> {
     return Promise.resolve(this.toolRegistry);
   }

packages/core/src/config/flashFallback.test.ts

@@ -4,14 +4,21 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-import { describe, it, expect, beforeEach } from 'vitest';
+import { describe, it, expect, beforeEach, vi } from 'vitest';
 import { Config } from './config.js';
 import { DEFAULT_GEMINI_MODEL, DEFAULT_GEMINI_FLASH_MODEL } from './models.js';
+import fs from 'node:fs';
+
+vi.mock('node:fs');
 
 describe('Flash Model Fallback Configuration', () => {
   let config: Config;
 
   beforeEach(() => {
+    vi.mocked(fs.existsSync).mockReturnValue(true);
+    vi.mocked(fs.statSync).mockReturnValue({
+      isDirectory: () => true,
+    } as fs.Stats);
     config = new Config({
       sessionId: 'test-session',
       targetDir: '/test',