MDnsClient throws uncatched exception when Android device disconnected from network #165482
Description
Steps to reproduce
- Disable WLAN in Android device
- Create and start MDnsClient:
final MDnsClient client = MDnsClient();
await client.start();
- Lookup for a service type:
List<PtrResourceRecord> ptrRecords = await client.lookup<PtrResourceRecord>(ResourceRecordQuery.serverPointer("_workstation._tcp.local")).toList();
Expected results
No exception happens, or exception can be catched with try-catch block around client.lookup.
Actual results
The following unhandled exception occurs, which leads the application to stop when running from debugger. The exception can not be handled with a try-catch block around MDnsClient.lookup.
E/flutter (19343): [ERROR:flutter/runtime/dart_vm_initializer.cc(40)] Unhandled Exception: SocketException: Send failed (OS Error: Network is unreachable, errno = 101), address = 0.0.0.0, port = 5353
E/flutter (19343): #0 _NativeSocket.send (dart:io-patch/socket_patch.dart:1512:34)
E/flutter (19343): #1 _RawDatagramSocket.send (dart:io-patch/socket_patch.dart:3070:15)
E/flutter (19343): #2 MDnsClient.lookup (package:multicast_dns/multicast_dns.dart:212:22)
E/flutter (19343): #3 main (package:bug/main.dart:10:22)
E/flutter (19343): <asynchronous suspension>
Code sample
Code sample
// ignore_for_file: avoid_print
import 'package:multicast_dns/multicast_dns.dart';
void main() async {
final MDnsClient client = MDnsClient();
await client.start();
try {
List<PtrResourceRecord> ptrRecords =
await client.lookup<PtrResourceRecord>(ResourceRecordQuery.serverPointer("_workstation._tcp.local")).toList();
print(ptrRecords);
} catch (e) {
print("Error: $e");
}
}
Screenshots or Video
Screenshots / Video demonstration
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Logs
Logs
flutter run
Launching lib/main.dart on Lenovo YT X705F in debug mode...
Running Gradle task 'assembleDebug'... 1.558ms
✓ Built build/app/outputs/flutter-apk/app-debug.apk
Installing build/app/outputs/flutter-apk/app-debug.apk... 4,9s
I/flutter (20555): [IMPORTANT:flutter/shell/platform/android/android_context_vk_impeller.cc(60)] Using the Impeller rendering backend (Vulkan).
E/flutter (20555): [ERROR:flutter/runtime/dart_vm_initializer.cc(40)] Unhandled Exception: SocketException: Send failed (OS Error: Network is unreachable, errno = 101), address = 0.0.0.0, port = 5353
E/flutter (20555): #0 _NativeSocket.send (dart:io-patch/socket_patch.dart:1512:34)
E/flutter (20555): #1 _RawDatagramSocket.send (dart:io-patch/socket_patch.dart:3070:15)
E/flutter (20555): #2 MDnsClient.lookup (package:multicast_dns/multicast_dns.dart:212:22)
E/flutter (20555): #3 main (package:bug/main.dart:10:22)
E/flutter (20555): <asynchronous suspension>
E/flutter (20555):
Syncing files to device Lenovo YT X705F... 4ms
Flutter run key commands.
r Hot reload. 🔥🔥🔥
R Hot restart.
h List all available interactive commands.
d Detach (terminate "flutter run" but leave application running).
c Clear the screen
q Quit (terminate the application on the device).
A Dart VM Service on Lenovo YT X705F is available at: http://127.0.0.1:35435/_2E3P-WqK_U=/
I/flutter (20555): []
D/ProfileInstaller(20555): Installing profile for com.example.bug
Application finished.Flutter Doctor output
Doctor output
[✓] Flutter (Channel stable, 3.29.0, on Ubuntu 24.04.1 LTS 6.8.0-55-generic, locale de_DE.UTF-8) [110ms]
• Flutter version 3.29.0 on channel stable at /home/airion/flutter
• Upstream repository https://github.com/flutter/flutter.git
• Framework revision 35c388afb5 (vor 5 Wochen), 2025-02-10 12:48:41 -0800
• Engine revision f73bfc4522
• Dart version 3.7.0
• DevTools version 2.42.2
[✓] Android toolchain - develop for Android devices (Android SDK version 35.0.1) [1.310ms]
• Android SDK at /home/airion/Android/Sdk
• Platform android-35, build-tools 35.0.1
• Java binary at: /snap/android-studio/161/jbr/bin/java
This is the JDK bundled with the latest Android Studio installation on this machine.
To manually set the JDK path, use: `flutter config --jdk-dir="path/to/jdk"`.
• Java version OpenJDK Runtime Environment (build 17.0.10+0-17.0.10b1087.21-11609105)
• All Android licenses accepted.
[✓] Chrome - develop for the web [14ms]
• Chrome at google-chrome
[✓] Linux toolchain - develop for Linux desktop [153ms]
• Ubuntu clang version 18.1.3 (1ubuntu1)
• cmake version 3.28.3
• ninja version 1.11.1
• pkg-config version 1.8.1
[✓] Android Studio (version 2024.1) [12ms]
• Android Studio at /snap/android-studio/161
• Flutter plugin can be installed from:
🔨 https://plugins.jetbrains.com/plugin/9212-flutter
• Dart plugin can be installed from:
🔨 https://plugins.jetbrains.com/plugin/6351-dart
• Java version OpenJDK Runtime Environment (build 17.0.10+0-17.0.10b1087.21-11609105)
[✓] VS Code (version 1.96.4) [10ms]
• VS Code at /usr/share/code
• Flutter extension version 3.106.0
[✓] Connected device (3 available) [186ms]
• Lenovo YT X705F (mobile) • HGAJG912 • android-arm64 • Android 10 (API 29)
• Linux (desktop) • linux • linux-x64 • Ubuntu 24.04.1 LTS 6.8.0-55-generic
• Chrome (web) • chrome • web-javascript • Google Chrome 132.0.6834.110
[✓] Network resources [282ms]
• All expected network resources are available.
• No issues found!