fix(a2a): Don't mutate 'replace' tool args in scheduleToolCalls (#7369)

Co-authored-by: Abhi <43648792+abhipatel12@users.noreply.github.com>

packages/a2a-server/src/task.test.ts

@@ -0,0 +1,59 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, it, expect, vi } from 'vitest';
+import { Task } from './task.js';
+import type { Config, ToolCallRequestInfo } from '@google/gemini-cli-core';
+import { createMockConfig } from './testing_utils.js';
+import type { ExecutionEventBus } from '@a2a-js/sdk/server';
+
+describe('Task', () => {
+  it('scheduleToolCalls should not modify the input requests array', async () => {
+    const mockConfig = createMockConfig();
+
+    const mockEventBus: ExecutionEventBus = {
+      publish: vi.fn(),
+      on: vi.fn(),
+      off: vi.fn(),
+      once: vi.fn(),
+      removeAllListeners: vi.fn(),
+      finished: vi.fn(),
+    };
+
+    // The Task constructor is private. We'll bypass it for this unit test.
+    // @ts-expect-error - Calling private constructor for test purposes.
+    const task = new Task(
+      'task-id',
+      'context-id',
+      mockConfig as Config,
+      mockEventBus,
+    );
+
+    task['setTaskStateAndPublishUpdate'] = vi.fn();
+    task['getProposedContent'] = vi.fn().mockResolvedValue('new content');
+
+    const requests: ToolCallRequestInfo[] = [
+      {
+        callId: '1',
+        name: 'replace',
+        args: {
+          file_path: 'test.txt',
+          old_string: 'old',
+          new_string: 'new',
+        },
+        isClientInitiated: false,
+        prompt_id: 'prompt-id-1',
+      },
+    ];
+
+    const originalRequests = JSON.parse(JSON.stringify(requests));
+    const abortController = new AbortController();
+
+    await task.scheduleToolCalls(requests, abortController.signal);
+
+    expect(requests).toEqual(originalRequests);
+  });
+});