Crash when pushing the app into the background and pulling it back into the foreground

[ctwdtw]

Describe the bug
Crash when pushing the app into the background and pulling it back into the foreground

To Reproduce
Steps to reproduce the behavior:

1. build a simple app with the following code, I use Bonsoir 4.0.0

import 'package:bonsoir/bonsoir.dart'; // 4.0.0
import 'package:flutter/material.dart';
import 'package:logger/logger.dart';

final logger = Logger();

void main() {
  runApp(const BonsoirApp());
}

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text('Simple Flutter App'),
        ),
        body: FutureBuilder(
          future: BonsoirDiscoverRepo.instance.init(),
          builder: (ctx, snapShot) {
            if (snapShot.connectionState == ConnectionState.done) {
              return const Text('discovering');
            } else {
              return const Text('waiting');
            }
          },
        ),
      ),
    );
  }
}

class BonsoirDiscoverRepo {
  static BonsoirDiscoverRepo get instance {
    _instance ??= BonsoirDiscoverRepo._internal();
    return _instance!;
  }

  static BonsoirDiscoverRepo? _instance;
  BonsoirDiscovery? _discover;

  BonsoirDiscoverRepo._internal();

  Future<void> init() async {
    if (_discover == null) {
      _discover = BonsoirDiscovery(type: '_http._tcp');
      await _discover!.ready;
      if (_discover!.eventStream == null) {
        return;
      }
      _discover!.eventStream!
          .where((event) => event.service?.name.contains('IGD-') ?? false)
          .listen(
        (event) async {
          if (event.type == BonsoirDiscoveryEventType.discoveryServiceFound) {
            event.service?.resolve(_discover!.serviceResolver);
          } else if (event.type ==
              BonsoirDiscoveryEventType.discoveryServiceResolved) {
            logger.d('resolve: ${event.service?.toJson()}');
          } else if (event.type ==
              BonsoirDiscoveryEventType.discoveryServiceLost) {
            logger.d('lost: ${event.service?.toJson()}');
          }
        },
      );
      await _discover!.start();
      logger.d('start discover and put event to lower stream');
    } else {
      logger.d('already start discover');
    }
  }
}

3. run the app with this command

fvm flutter run -d <my_iPhone_device_id> --release

4. Push the app into the background
5. Pulling the app into the foreground
6. The App Crashed.

Expected behavior
Should not crash, when I comment out the code inside Future<void> init() async {}, it did not crash

Screenshots
N/A

Desktop (please complete the following information):
Not Testing

Smartphone (please complete the following information):

• Device: iPhone11
• OS: iOS16.6.1

Additional context
I am not sure if I'm using Bonsoir in the correct way. My use case is the following:

1. When a user holds my app and enters a room, the app can display devices broadcast its service name with the prefix MY_DEVICE_PREFIX
2. When a user holds my app and leaves a room, the app can display the remaining devices broadcast its service name with the prefix MY_DEVICE_PREFIX (which could be none)

If I understand Bonsoir's behavior correctly, I think the above requirements can be imp. as a singleton. However, even if I update
Bonsoir to 4.0.0, the discovering behavior seems still not stable. I may open another issue to describe it. Thank you.

[ctwdtw]

I also tested the example project with the following steps, and it crashed:

1. Open Runner.xcworkspace in Xcode
2. set EditScheme -> Run -> Build Configuration as Release
3. run the app on an iPhone Simulator
4. it crashes with the following message:

  Details

Simulator device returned an error for the requested operation.
Domain: NSPOSIXErrorDomain
Code: 3
Failure Reason: No such process
User Info: {
    DVTErrorCreationDateKey = "2023-11-17 09:32:07 +0000";
    IDERunOperationFailingWorker = IDELaunchiPhoneSimulatorLauncher;
    SimCallingSelector = "launchApplicationWithID:options:pid:error:";
}
--
Application launch for 'fr.skyost.bonsoirExample' did not return a valid pid nor a launch error.
Domain: NSPOSIXErrorDomain
Code: 3
Failure Reason: No such process
--

Analytics Event: com.apple.dt.IDERunOperationWorkerFinished : {
    "device_model" = "iPhone14,7";
    "device_osBuild" = "16.4 (20E247)";
    "device_platform" = "com.apple.platform.iphonesimulator";
    "launchSession_schemeCommand" = Run;
    "launchSession_state" = 1;
    "launchSession_targetArch" = arm64;
    "operation_duration_ms" = 372;
    "operation_errorCode" = 3;
    "operation_errorDomain" = NSPOSIXErrorDomain;
    "operation_errorWorker" = IDELaunchiPhoneSimulatorLauncher;
    "operation_name" = IDERunOperationWorkerGroup;
    "param_consoleMode" = 0;
    "param_debugger_attachToExtensions" = 0;
    "param_debugger_attachToXPC" = 1;
    "param_debugger_type" = 3;
    "param_destination_isProxy" = 0;
    "param_destination_platform" = "com.apple.platform.iphonesimulator";
    "param_diag_MainThreadChecker_stopOnIssue" = 0;
    "param_diag_MallocStackLogging_enableDuringAttach" = 0;
    "param_diag_MallocStackLogging_enableForXPC" = 1;
    "param_diag_allowLocationSimulation" = 1;
    "param_diag_checker_tpc_enable" = 1;
    "param_diag_gpu_frameCapture_enable" = 0;
    "param_diag_gpu_shaderValidation_enable" = 0;
    "param_diag_gpu_validation_enable" = 0;
    "param_diag_memoryGraphOnResourceException" = 0;
    "param_diag_queueDebugging_enable" = 1;
    "param_diag_runtimeProfile_generate" = 0;
    "param_diag_sanitizer_asan_enable" = 0;
    "param_diag_sanitizer_tsan_enable" = 0;
    "param_diag_sanitizer_tsan_stopOnIssue" = 0;
    "param_diag_sanitizer_ubsan_stopOnIssue" = 0;
    "param_diag_showNonLocalizedStrings" = 0;
    "param_diag_viewDebugging_enabled" = 1;
    "param_diag_viewDebugging_insertDylibOnLaunch" = 1;
    "param_install_style" = 0;
    "param_launcher_UID" = 2;
    "param_launcher_allowDeviceSensorReplayData" = 0;
    "param_launcher_kind" = 0;
    "param_launcher_style" = 0;
    "param_launcher_substyle" = 0;
    "param_runnable_appExtensionHostRunMode" = 0;
    "param_runnable_productType" = "com.apple.product-type.application";
    "param_testing_launchedForTesting" = 0;
    "param_testing_suppressSimulatorApp" = 0;
    "param_testing_usingCLI" = 0;
    "sdk_canonicalName" = "iphonesimulator16.4";
    "sdk_osVersion" = "16.4";
    "sdk_variant" = iphonesimulator;
}
--


System Information

macOS Version 13.5 (Build 22G74)
Xcode 14.3.1 (21815) (Build 14E300c)
Timestamp: 2023-11-17T17:32:07+08:00

[Skyost]

Hey,

Your code seems correct. Is the error detailed in #65 (comment) the same you're describing in your first message ?

[ctwdtw]

No, when using fvm flutter run -d <my_iPhone_device_id> --release I did not get a crash stack trace. the app just crashed. I may need to install Crashlytic to dump the stack trace.

I guess the crash is because of the release build, that's why I tested the example project by changing EditScheme -> Run -> Build Configuration as Release and to my surprise, it crashed right after I ran the example app.

I have pushed a repo so that you can reproduce the bug I described here #65 (comment)

https://github.com/ctwdtw/bonsoir_report

please have a look, thanks.

[Skyost]

Just tried to reproduce the bug thanks to your repo (https://github.com/ctwdtw/bonsoir_report), but the "push to background" - "pull into foreground" sequence doesn't seem to produce any crash, in debug mode at least.

[ctwdtw]

Yes, it does not crash in debug mode. As I pointed out in step 3 of how to reproduce the bug:
fvm flutter run -d <my_iPhone_device_id> --release, it did crash on release mode with the push to background, and pull into foreground sequence.

[Skyost]

Just reproduced your bug, and I get the following message :

Unsupported value: -65569: Defunct connection of type __SwiftNativeNSerror

It seems that we're trying to send a __SwiftNativeNSerror to the Dart side, which is causing a crash.

[olerhan]

Hello,
I encounter the following error when bringing my iOS application from the background to the foreground:

dnssd_clientstub write_all(22) DEFUNCT
dnssd_clientstub deliver_request ERROR: write_all(22, 88 bytes) failed
dnssd_clientstub write_all(22) DEFUNCT

After this, Bonsoir does not work properly. Is this a condition that needs to be managed, or is it a bug?

[Skyost]

@olerhan I don't know about this one. Does it happen with the example app ?