refactor(acp): centralize error codes and add RESOURCE_NOT_FOUND handling for file operations

packages/cli/src/acp-integration/acp.ts

@@ -8,6 +8,7 @@
 
 import { z } from 'zod';
 import * as schema from './schema.js';
+import { ACP_ERROR_CODES } from './errorCodes.js';
 export * from './schema.js';
 
 import type { WritableStream, ReadableStream } from 'node:stream/web';
@@ -349,27 +350,51 @@ export class RequestError extends Error {
   }
 
   static parseError(details?: string): RequestError {
-    return new RequestError(-32700, 'Parse error', details);
+    return new RequestError(
+      ACP_ERROR_CODES.PARSE_ERROR,
+      'Parse error',
+      details,
+    );
   }
 
   static invalidRequest(details?: string): RequestError {
-    return new RequestError(-32600, 'Invalid request', details);
+    return new RequestError(
+      ACP_ERROR_CODES.INVALID_REQUEST,
+      'Invalid request',
+      details,
+    );
   }
 
   static methodNotFound(details?: string): RequestError {
-    return new RequestError(-32601, 'Method not found', details);
+    return new RequestError(
+      ACP_ERROR_CODES.METHOD_NOT_FOUND,
+      'Method not found',
+      details,
+    );
   }
 
   static invalidParams(details?: string): RequestError {
-    return new RequestError(-32602, 'Invalid params', details);
+    return new RequestError(
+      ACP_ERROR_CODES.INVALID_PARAMS,
+      'Invalid params',
+      details,
+    );
   }
 
   static internalError(details?: string): RequestError {
-    return new RequestError(-32603, 'Internal error', details);
+    return new RequestError(
+      ACP_ERROR_CODES.INTERNAL_ERROR,
+      'Internal error',
+      details,
+    );
   }
 
   static authRequired(details?: string): RequestError {
-    return new RequestError(-32000, 'Authentication required', details);
+    return new RequestError(
+      ACP_ERROR_CODES.AUTH_REQUIRED,
+      'Authentication required',
+      details,
+    );
   }
 
   toResult<T>(): Result<T> {

packages/cli/src/acp-integration/errorCodes.ts

@@ -0,0 +1,25 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+export const ACP_ERROR_CODES = {
+  // Parse error: invalid JSON received by server.
+  PARSE_ERROR: -32700,
+  // Invalid request: JSON is not a valid Request object.
+  INVALID_REQUEST: -32600,
+  // Method not found: method does not exist or is unavailable.
+  METHOD_NOT_FOUND: -32601,
+  // Invalid params: invalid method parameter(s).
+  INVALID_PARAMS: -32602,
+  // Internal error: implementation-defined server error.
+  INTERNAL_ERROR: -32603,
+  // Authentication required: must authenticate before operation.
+  AUTH_REQUIRED: -32000,
+  // Resource not found: e.g. missing file.
+  RESOURCE_NOT_FOUND: -32002,
+} as const;
+
+export type AcpErrorCode =
+  (typeof ACP_ERROR_CODES)[keyof typeof ACP_ERROR_CODES];

packages/cli/src/acp-integration/service/filesystem.ts

@@ -6,6 +6,7 @@
 
 import type { FileSystemService } from '@qwen-code/qwen-code-core';
 import type * as acp from '../acp.js';
+import { ACP_ERROR_CODES } from '../errorCodes.js';
 
 /**
  * ACP client-based implementation of FileSystemService
@@ -23,25 +24,31 @@ export class AcpFileSystemService implements FileSystemService {
       return this.fallback.readTextFile(filePath);
     }
 
-    const response = await this.client.readTextFile({
-      path: filePath,
-      sessionId: this.sessionId,
-      line: null,
-      limit: null,
-    });
+    let response: { content: string };
+    try {
+      response = await this.client.readTextFile({
+        path: filePath,
+        sessionId: this.sessionId,
+        line: null,
+        limit: null,
+      });
+    } catch (error) {
+      const errorCode =
+        typeof error === 'object' && error !== null && 'code' in error
+          ? (error as { code?: unknown }).code
+          : undefined;
 
-    if (response.content.startsWith('ERROR: ENOENT:')) {
-      // Treat ACP error strings as structured ENOENT errors without
-      // assuming a specific platform format.
-      const match = /^ERROR:\s*ENOENT:\s*(?<path>.*)$/i.exec(response.content);
-      const err = new Error(response.content) as NodeJS.ErrnoException;
-      err.code = 'ENOENT';
-      err.errno = -2;
-      const rawPath = match?.groups?.['path']?.trim();
-      err['path'] = rawPath
-        ? rawPath.replace(/^['"]|['"]$/g, '') || filePath
-        : filePath;
-      throw err;
+      if (errorCode === ACP_ERROR_CODES.RESOURCE_NOT_FOUND) {
+        const err = new Error(
+          `File not found: ${filePath}`,
+        ) as NodeJS.ErrnoException;
+        err.code = 'ENOENT';
+        err.errno = -2;
+        err.path = filePath;
+        throw err;
+      }
+
+      throw error;
     }
 
     return response.content;