CODEWITHSUNDEEP
dartflutter
Waymond
Waymond

Reputation: 257

Getting a configuration engine error when trying hot restart in flutter application

I'm learning streams/bloc pattern in dart/flutter and can't pinpoint where the error is coming from when I try to run my app. I assume the stream is getting hung up somewhere judging by the async errors. I am usingdispose() and closing out the streams inside it. Any help would be appreciated.

Here is the code. I put it all in one big chunk but commented which file each of the code chunks is from:

 // bloc.dart
 import 'dart:async';
 import 'validators.dart';

class Bloc extends Validators {
  final _email = new StreamController<String>();
  final _password = new StreamController<String>();

  // Add data to stream
  Stream<String> get email => _email.stream.transform(validateEmail);
  Stream<String> get password => _password.stream.transform(validatePassword);

  // Change Data
  Function(String) get changeEmail => _email.sink.add;
  Function(String) get changePassword => _password.sink.add;

  dispose() {
    _email.close();
    _password.close();
  }
}

final bloc = Bloc();

// login_screen.dart
import 'package:flutter/material.dart';
import '../blocs/bloc.dart';

class LoginScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Container(
        margin: EdgeInsets.all(20.0),
        child: Column(
          children: [
            emailField(),
            passwordField(),
            Container(
              margin: EdgeInsets.only(top: 25.0),
            ),
            raisedButton()
          ],
        ));
  }

  Widget emailField() {
    return StreamBuilder(
        stream: bloc.email,
        builder: (context, snapshot) {
          return TextField(
            onChanged: bloc.changeEmail,
            keyboardType: TextInputType.emailAddress,
            decoration: InputDecoration(
                hintText: '[email protected]',
                labelText: 'Enter your email!',
                errorText: snapshot.error),
          );
        });
  }

  Widget passwordField() {
    return TextField(
      obscureText: true,
      decoration: InputDecoration(hintText: 'password', labelText: 'password'),
    );
  }

  Widget raisedButton() {
    return RaisedButton(
      child: Text('Login'),
      color: Colors.blue,
      onPressed: () {},
    );
  }
}

// validation.dart
import 'dart:async';

class Validators {
  final validateEmail =
      StreamTransformer<String, String>.fromHandlers(handleData: (email, sink) {
    if (email.contains('@')) {
      sink.add(email);
    } else {
      sink.addError('Please enter valid email');
    }
  });

  final validatePassword = StreamTransformer<String, String>.fromHandlers(
      handleData: (password, sink) {
    if (password.length > 4) {
      sink.add(password);
    } else {
      sink.addError('Please enter the right number of characters');
    }
  });
}

Here is the error I am getting when I try to hot restart my app:

⣯[VERBOSE-2:shell.cc(181)] Dart Error: Can't load Kernel binary: Invalid kernel binary format version.
[VERBOSE-2:engine.cc(158)] Could not prepare to run the isolate.
[VERBOSE-2:engine.cc(117)] Engine not prepare and launch isolate.
Error -32000 received from application: Could not run configuration in engine.

JSON-RPC error -32000: Could not run configuration in engine.
package:json_rpc_2/src/client.dart 110:64              Client.sendRequest
package:json_rpc_2/src/peer.dart 68:15                 Peer.sendRequest
package:flutter_tools/src/vmservice.dart 293:13        VMService._sendRequest
package:flutter_tools/src/vmservice.dart 842:12        VM.invokeRpcRaw
===== asynchronous gap ===========================
package:flutter_tools/src/vmservice.dart 865:49        VM.invokeRpc
===== asynchronous gap ===========================
package:flutter_tools/src/vmservice.dart 932:12        VM.runInView
package:flutter_tools/src/vmservice.dart 1439:20       FlutterView.runFromSource
===== asynchronous gap ===========================
package:flutter_tools/src/run_hot.dart 379:18          HotRunner._launchInView
===== asynchronous gap ===========================
package:flutter_tools/src/run_hot.dart 390:13          HotRunner._launchFromDevFS
===== asynchronous gap ===========================
package:flutter_tools/src/run_hot.dart 442:11          HotRunner._restartFromSources
===== asynchronous gap ===========================
package:flutter_tools/src/run_hot.dart 505:15          HotRunner.restart
===== asynchronous gap ===========================
package:flutter_tools/src/run_hot.dart 282:44          HotRunner.handleTerminalCommand
===== asynchronous gap ===========================
package:flutter_tools/src/resident_runner.dart 754:15  ResidentRunner.processTerminalInput
===== asynchronous gap ===========================
dart:async/zone.dart 1132:38                           _rootRunUnary
dart:async/zone.dart 1029:19                           _CustomZone.runUnary
dart:async/zone.dart 931:7                             _CustomZone.runUnaryGuarded
dart:async/stream_impl.dart 336:11                     _BufferingStreamSubscription._sendData
dart:async/stream_impl.dart 263:7                      _BufferingStreamSubscription._add
dart:async/broadcast_stream_controller.dart 379:20     _SyncBroadcastStreamController._sendData
dart:async/broadcast_stream_controller.dart 254:5      _BroadcastStreamController.add
dart:async/broadcast_stream_controller.dart 480:11     _AsBroadcastStreamController.add
dart:async/zone.dart 1132:38                           _rootRunUnary
dart:async/zone.dart 1029:19                           _CustomZone.runUnary
dart:async/zone.dart 931:7                             _CustomZone.runUnaryGuarded
dart:async/stream_impl.dart 336:11                     _BufferingStreamSubscription._sendData
dart:async/stream_impl.dart 263:7                      _BufferingStreamSubscription._add
dart:async/stream_transformers.dart 68:11              _SinkTransformerStreamSubscription._add
dart:async/stream_transformers.dart 15:11              _EventSinkWrapper.add
dart:convert/string_conversion.dart 268:11             _StringAdapterSink.add
dart:convert/string_conversion.dart 273:7              _StringAdapterSink.addSlice
dart:convert/string_conversion.dart 348:20             _Utf8ConversionSink.addSlice
dart:convert/ascii.dart 278:17                         _ErrorHandlingAsciiDecoderSink.addSlice
dart:convert/ascii.dart 264:5                          _ErrorHandlingAsciiDecoderSink.add
dart:convert/chunked_conversion.dart 86:18             _ConverterStreamEventSink.add
dart:async/stream_transformers.dart 120:24             _SinkTransformerStreamSubscription._handleData
dart:async/zone.dart 1132:38                           _rootRunUnary
dart:async/zone.dart 1029:19                           _CustomZone.runUnary
dart:async/zone.dart 931:7                             _CustomZone.runUnaryGuarded
dart:async/stream_impl.dart 336:11                     _BufferingStreamSubscription._sendData
dart:async/stream_impl.dart 263:7                      _BufferingStreamSubscription._add
dart:async/stream_controller.dart 763:19               _SyncStreamController._sendData
dart:async/stream_controller.dart 639:7                _StreamController._add
dart:async/stream_controller.dart 585:5                _StreamController.add
dart:io/runtime/binsocket_patch.dart 1714:41           _Socket._onData
dart:async/zone.dart 1136:13                           _rootRunUnary
dart:async/zone.dart 1029:19                           _CustomZone.runUnary
dart:async/zone.dart 931:7                             _CustomZone.runUnaryGuarded
dart:async/stream_impl.dart 336:11                     _BufferingStreamSubscription._sendData
dart:async/stream_impl.dart 263:7                      _BufferingStreamSubscription._add
dart:async/stream_controller.dart 763:19               _SyncStreamController._sendData
dart:async/stream_controller.dart 639:7                _StreamController._add
dart:async/stream_controller.dart 585:5                _StreamController.add
dart:io/runtime/binsocket_patch.dart 1276:33           new _RawSocket.<fn>
dart:io/runtime/binsocket_patch.dart 819:14            _NativeSocket.issueReadEvent.issue
dart:async/schedule_microtask.dart 41:21               _microtaskLoop
dart:async/schedule_microtask.dart 50:5                _startMicrotaskLoop
dart:isolate/runtime/libisolate_patch.dart 115:13      _runPendingImmediateCallback
dart:isolate/runtime/libisolate_patch.dart 172:5       _RawReceivePortImpl._handleMessage

edit: When I do a hot reload instead of a hot restart, I get this error:

    Initializing hot reload...                                      ⣟Hot reload failed: type 'TimeoutException' is not a subtype of type 'Map<String, dynamic>'
#0      HotRunner._reloadSources.<anonymous closure> (package:flutter_tools/src/run_hot.dart:587:45)
#1      _rootRunUnary (dart:async/zone.dart:1132:38)
#2      _CustomZone.runUnary (dart:async/zone.dart:1029:19)
#3      _FutureListener.handleError (dart:async/future_impl.dart:147:20)
#4      Future._propagateToListeners.handleError (dart:async/future_impl.dart:654:47)
#5      Future._propagateToListeners (dart:async/future_impl.dart:675:24)
#6      Future._completeError (dart:async/future_impl.dart:494:5)
#7      Future.wait.handleError (dart:async/future.dart:379:18)
#8      _rootRunBinary (dart:async/zone.dart:1144:38)
#9      _CustomZone.runBinary (dart:async/zone.dart:1037:19)
#10     _FutureListener.handleError (dart:async/future_impl.dart:143:20)
#11     Future._propagateToListeners.handleError (dart:async/future_impl.dart:654:47)
#12     Future._propagateToListeners (dart:async/future_impl.dart:675:24)
#13     Future._completeError (dart:async/future_impl.dart:494:5)
#14     _SyncCompleter._completeError (dart:async/future_impl.dart:55:12)
#15     _Completer.completeError (dart:async/future_impl.dart:27:5)
#16     _AsyncAwaitCompleter.completeError (dart:async/runtime/libasync_patch.dart:40:18)
#17     Isolate.reloadSources (package:flutter_tools/src/vmservice.dart)
<asynchronous suspension>
#18     FlutterDevice.reloadSources (package:flutter_tools/src/resident_runner.dart:144:66)
#19     HotRunner._reloadSources (package:flutter_tools/src/run_hot.dart:579:67)
<asynchronous suspension>
#20     HotRunner.restart (package:flutter_tools/src/run_hot.dart:520:24)
<asynchronous suspension>
#21     HotRunner.handleTerminalCommand (package:flutter_tools/src/run_hot.dart:282:44)
<asynchronous suspension>
#22     ResidentRunner.processTerminalInput (package:flutter_tools/src/resident_runner.dart:754:15)
<asynchronous suspension>
#23     _rootRunUnary (dart:async/zone.dart:1132:38)
#24     _CustomZone.runUnary (dart:async/zone.dart:1029:19)
#25     _CustomZone.runUnaryGuarded (dart:async/zone.dart:931:7)
#26     _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:336:11)
#27     _BufferingStreamSubscription._add (dart:async/stream_impl.dart:263:7)
#28     _SyncBroadcastStreamController._sendData (dart:async/broadcast_stream_controller.dart:379:20)
#29     _BroadcastStreamController.add (dart:async/broadcast_stream_controller.dart:254:5)
#30     _AsBroadcastStreamController.add (dart:async/broadcast_stream_controller.dart:480:11)
#31     _rootRunUnary (dart:async/zone.dart:1132:38)
#32     _CustomZone.runUnary (dart:async/zone.dart:1029:19)
#33     _CustomZone.runUnaryGuarded (dart:async/zone.dart:931:7)
#34     _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:336:11)
#35     _BufferingStreamSubscription._add (dart:async/stream_impl.dart:263:7)
#36     _SinkTransformerStreamSubscription._add (dart:async/stream_transformers.dart:68:11)
#37     _EventSinkWrapper.add (dart:async/stream_transformers.dart:15:11)
#38     _StringAdapterSink.add (dart:convert/string_conversion.dart:268:11)
#39     _StringAdapterSink.addSlice (dart:convert/string_conversion.dart:273:7)
#40     _Utf8ConversionSink.addSlice (dart:convert/string_conversion.dart:348:20)
#41     _ErrorHandlingAsciiDecoderSink.addSlice (dart:convert/ascii.dart:278:17)
#42     _ErrorHandlingAsciiDecoderSink.add (dart:convert/ascii.dart:264:5)
#43     _ConverterStreamEventSink.add (dart:convert/chunked_conversion.dart:86:18)
#44     _SinkTransformerStreamSubscription._handleData (dart:async/stream_transformers.dart:120:24)
#45     _rootRunUnary (dart:async/zone.dart:1132:38)
#46     _CustomZone.runUnary (dart:async/zone.dart:1029:19)
#47     _CustomZone.runUnaryGuarded (dart:async/zone.dart:931:7)
#48     _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:336:11)
#49     _BufferingStreamSubscription._add (dart:async/stream_impl.dart:263:7)
#50     _SyncStreamController._sendData (dart:async/stream_controller.dart:763:19)
#51     _StreamController._add (dart:async/stream_controller.dart:639:7)
#52     _StreamController.add (dart:async/stream_controller.dart:585:5)
#53     _Socket._onData (dart:io/runtime/binsocket_patch.dart:1714:41)
#54     _rootRunUnary (dart:async/zone.dart:1136:13)
#55     _CustomZone.runUnary (dart:async/zone.dart:1029:19)
#56     _CustomZone.runUnaryGuarded (dart:async/zone.dart:931:7)
#57     _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:336:11)
#58     _BufferingStreamSubscription._add (dart:async/stream_impl.dart:263:7)
#59     _SyncStreamController._sendData (dart:async/stream_controller.dart:763:19)
#60     _StreamController._add (dart:async/stream_controller.dart:639:7)
#61     _StreamController.add (dart:async/stream_controller.dart:585:5)
#62     new _RawSocket.<anonymous closure> (dart:io/runtime/binsocket_patch.dart:1276:33)
#63     _NativeSocket.issueReadEvent.issue (dart:io/runtime/binsocket_patch.dart:819:14)
#64     _microtaskLoop (dart:async/schedule_microtask.dart:41:21)
#65     _startMicrotaskLoop (dart:async/schedule_microtask.dart:50:5)
#66     _runPendingImmediateCallback (dart:isolate/runtime/libisolate_patch.dart:115:13)
#67     _RawReceivePortImpl._handleMessage (dart:isolate/runtime/libisolate_patch.dart:172:5)

Upvotes: 1

Views: 3040

Answers (2)

cbracken
cbracken

Reputation: 3800

A case where you'll frequently run into this is if you're building your own engine from source, and using it via flutter's --local-engine option.

Dart code in a Flutter app is initially compiled through the Dart kernel compiler, which emits a .dill file in an intermediate format. This intermediate format includes an identifier that the Dart VM in the Flutter engine uses to validate that it's compatible with that VM version. The root cause of an Invalid kernel binary format version error message is that the .dill file in question was generated with an incompatible version of the kernel compiler.

To resolve this, after rebuilding the engine for your device (e.g. android_debug_unopt), you'll want to ensure that you've also rebuilt the associated host toolchain (e.g. host_debug_unopt).

If you're seeing this in other cases, it's almost certainly a bug, and I'd definitely encourage you to open an issue against Flutter.

Upvotes: 1

G&#252;nter Z&#246;chbauer
G&#252;nter Z&#246;chbauer

Reputation: 657801

There was a bug fixed very recently that resulted in this error message https://github.com/flutter/flutter/issues/21348

I would expect this to be included in the latest Flutter dev and master channel.

To switch to the dev channel use

flutter channel dev
flutter doctor

update

(from https://github.com/flutter/flutter/issues/22964#issuecomment-429071970)

import './src/app.dart'; in lib/main.dart is the culprit.
lib/main.dart must not contain relative imports and must not be imported from other files

https://github.com/dart-lang/sdk#33076 was just fixed but it will take a while until it lands in Flutter.

Upvotes: 1

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