Add support for an additional exclusion file besides .gitignore and .geminiignore (#16487)

Co-authored-by: Adam Weidman <adamfweidman@google.com>

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

@@ -13,6 +13,7 @@ import { debugLogger } from '../utils/debugLogger.js';
 import { ApprovalMode } from '../policy/types.js';
 import type { HookDefinition } from '../hooks/types.js';
 import { HookType, HookEventName } from '../hooks/types.js';
+import { FileDiscoveryService } from '../services/fileDiscoveryService.js';
 import * as path from 'node:path';
 import * as fs from 'node:fs';
 import { setGeminiMdFilename as mockSetGeminiMdFilename } from '../tools/memoryTool.js';
@@ -138,6 +139,8 @@ vi.mock('../services/gitService.js', () => {
   return { GitService: GitServiceMock };
 });
 
+vi.mock('../services/fileDiscoveryService.js');
+
 vi.mock('../ide/ide-client.js', () => ({
   IdeClient: {
     getInstance: vi.fn().mockResolvedValue({
@@ -623,6 +626,30 @@ describe('Server Config (config.ts)', () => {
     expect(config.getFileFilteringRespectGitIgnore()).toBe(false);
   });
 
+  it('should set customIgnoreFilePaths from params', () => {
+    const params: ConfigParameters = {
+      ...baseParams,
+      fileFiltering: {
+        customIgnoreFilePaths: ['/path/to/ignore/file'],
+      },
+    };
+    const config = new Config(params);
+    expect(config.getCustomIgnoreFilePaths()).toStrictEqual([
+      '/path/to/ignore/file',
+    ]);
+  });
+
+  it('should set customIgnoreFilePaths to empty array if not provided', () => {
+    const params: ConfigParameters = {
+      ...baseParams,
+      fileFiltering: {
+        respectGitIgnore: true,
+      },
+    };
+    const config = new Config(params);
+    expect(config.getCustomIgnoreFilePaths()).toStrictEqual([]);
+  });
+
   it('should initialize WorkspaceContext with includeDirectories', () => {
     const includeDirectories = ['dir1', 'dir2'];
     const paramsWithIncludeDirs: ConfigParameters = {
@@ -699,6 +726,29 @@ describe('Server Config (config.ts)', () => {
     expect(fileService).toBeDefined();
   });
 
+  it('should pass file filtering options to FileDiscoveryService', () => {
+    const configParams = {
+      ...baseParams,
+      fileFiltering: {
+        respectGitIgnore: false,
+        respectGeminiIgnore: false,
+        customIgnoreFilePaths: ['.myignore'],
+      },
+    };
+
+    const config = new Config(configParams);
+    config.getFileService();
+
+    expect(FileDiscoveryService).toHaveBeenCalledWith(
+      path.resolve(TARGET_DIR),
+      {
+        respectGitIgnore: false,
+        respectGeminiIgnore: false,
+        customIgnoreFilePaths: ['.myignore'],
+      },
+    );
+  });
+
   describe('Usage Statistics', () => {
     it('defaults usage statistics to enabled if not specified', () => {
       const config = new Config({

packages/core/src/config/config.ts

@@ -328,6 +328,7 @@ export interface ConfigParameters {
     enableFuzzySearch?: boolean;
     maxFileCount?: number;
     searchTimeout?: number;
+    customIgnoreFilePaths?: string[];
   };
   checkpointing?: boolean;
   proxy?: string;
@@ -465,6 +466,7 @@ export class Config {
     enableFuzzySearch: boolean;
     maxFileCount: number;
     searchTimeout: number;
+    customIgnoreFilePaths: string[];
   };
   private fileDiscoveryService: FileDiscoveryService | null = null;
   private gitService: GitService | undefined = undefined;
@@ -631,6 +633,7 @@ export class Config {
         params.fileFiltering?.searchTimeout ??
         DEFAULT_FILE_FILTERING_OPTIONS.searchTimeout ??
         5000,
+      customIgnoreFilePaths: params.fileFiltering?.customIgnoreFilePaths ?? [],
     };
     this.checkpointing = params.checkpointing ?? false;
     this.proxy = params.proxy;
@@ -1528,16 +1531,22 @@ export class Config {
   getFileFilteringRespectGitIgnore(): boolean {
     return this.fileFiltering.respectGitIgnore;
   }
+
   getFileFilteringRespectGeminiIgnore(): boolean {
     return this.fileFiltering.respectGeminiIgnore;
   }
 
+  getCustomIgnoreFilePaths(): string[] {
+    return this.fileFiltering.customIgnoreFilePaths;
+  }
+
   getFileFilteringOptions(): FileFilteringOptions {
     return {
       respectGitIgnore: this.fileFiltering.respectGitIgnore,
       respectGeminiIgnore: this.fileFiltering.respectGeminiIgnore,
       maxFileCount: this.fileFiltering.maxFileCount,
       searchTimeout: this.fileFiltering.searchTimeout,
+      customIgnoreFilePaths: this.fileFiltering.customIgnoreFilePaths,
     };
   }
 
@@ -1574,7 +1583,11 @@ export class Config {
 
   getFileService(): FileDiscoveryService {
     if (!this.fileDiscoveryService) {
-      this.fileDiscoveryService = new FileDiscoveryService(this.targetDir);
+      this.fileDiscoveryService = new FileDiscoveryService(this.targetDir, {
+        respectGitIgnore: this.fileFiltering.respectGitIgnore,
+        respectGeminiIgnore: this.fileFiltering.respectGeminiIgnore,
+        customIgnoreFilePaths: this.fileFiltering.customIgnoreFilePaths,
+      });
     }
     return this.fileDiscoveryService;
   }

packages/core/src/config/constants.ts

@@ -9,6 +9,7 @@ export interface FileFilteringOptions {
   respectGeminiIgnore: boolean;
   maxFileCount?: number;
   searchTimeout?: number;
+  customIgnoreFilePaths: string[];
 }
 
 // For memory files
@@ -17,6 +18,7 @@ export const DEFAULT_MEMORY_FILE_FILTERING_OPTIONS: FileFilteringOptions = {
   respectGeminiIgnore: true,
   maxFileCount: 20000,
   searchTimeout: 5000,
+  customIgnoreFilePaths: [],
 };
 
 // For all other files
@@ -25,4 +27,8 @@ export const DEFAULT_FILE_FILTERING_OPTIONS: FileFilteringOptions = {
   respectGeminiIgnore: true,
   maxFileCount: 20000,
   searchTimeout: 5000,
+  customIgnoreFilePaths: [],
 };
+
+// Generic exclusion file name
+export const GEMINI_IGNORE_FILE_NAME = '.geminiignore';