[cannot repro] flutter_driver tap command fails with type cast error

[get6]

Description

The flutter_driver tool's tap command fails with a type cast error when attempting to interact with widgets.

Steps to Reproduce

1. Connect to a running Flutter app via DTD
2. Execute the flutter_driver command with tap action

{
  "command": "tap",
  "finderType": "ByTooltipMessage",
  "text": "Settings",
  "timeout": 5000
}

Or with ByType:

  {
    "command": "tap",
    "finderType": "ByType",
    "type": "BottomNavigationBar",
    "timeout": 5000
  }

Error Message

  type 'int' is not a subtype of type 'String?' in type cast
  #0      DartToolingDaemonSupport._callFlutterDriver.<anonymous closure> (package:dart_mcp_server/src/mixins/dtd.dart:187)
  <asynchronous suspension>
  #1      DartToolingDaemonSupport._callOnVmService (package:dart_mcp_server/src/mixins/dtd.dart:667)
  <asynchronous suspension>
  #2      DartMCPServer.registerTool.<anonymous closure> (package:dart_mcp_server/src/server.dart:193)
  <asynchronous suspension>
  #3      ToolsSupport._callTool (package:dart_mcp/src/server/tools_support.dart:113)
  <asynchronous suspension>
  #4      Server._handleSingleRequest (package:json_rpc_2/src/server.dart:212)
  <asynchronous suspension>
  #5      Server._handleRequest (package:json_rpc_2/src/server.dart:187)
  <asynchronous suspension>

Environment

• dart_mcp_server: latest (via npx)
• Flutter: 3.38.4
• Dart SDK: 3.9.2
• OS: macOS

Expected Behavior

The tap command should successfully tap on the specified widget.

Actual Behavior

The command fails immediately with a type cast error, suggesting an issue in the response parsing at dtd.dart:187.

[csells]

oh! that sounds like a bug. let me track that down.

[csells]

I have attempted to reproduce this issue using a minimal Flutter app and the standard flutter_driver package on macos.

The tap command works correctly when using the standard flutter drive tooling. This suggests the issue is likely specific to dart_mcp_server.

To repo, I created a minimal app and a minimal test to isolate the behavior. Note: Your recommended tap scripts are against widgets that the LlmChatView doesn't use, so I tested against the TextField that is used.

test_driver/issue_174_repro.dart (test app):

import 'package:flutter/material.dart';
import 'package:flutter_ai_toolkit/flutter_ai_toolkit.dart';
import 'package:flutter_driver/driver_extension.dart';

void main() {
  enableFlutterDriverExtension();
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(title: const Text('Issue 174 Repro')),
        body: LlmChatView(provider: EchoProvider()),
      ),
    );
  }
}

test_driver/issue_174_repro_test.dart (test script):

import 'package:flutter_driver/flutter_driver.dart';
import 'package:test/test.dart';

void main() {
  group('Issue 174 Repro App', () {
    late FlutterDriver driver;

    // Connect to the Flutter driver before running any tests.
    setUpAll(() async {
      driver = await FlutterDriver.connect();
      await driver.waitUntilFirstFrameRasterized();
    });

    // Close the connection to the driver after the tests have completed.
    tearDownAll(() async {
      await driver.close();
    });

    test('taps the text field', () async {
      final textFieldFinder = find.byType('TextField');
      await driver.tap(textFieldFinder);
    });
  });
}

Running flutter drive --target=test_driver/issue_174_repro.dart -d macos passes successfully.