Compiler crashes when Future is created and awaited later (during debug)

[bernardolansing]

I am developing an Android app with Flutter. This afternoon, I started to receive this error:

Compiler crash

Unhandled exception:
invalid input
#0 parseDefinitionTypes (package:front_end/src/api_prototype/expression_compilation_tools.dart:110:43)
#1 createDefinitionsWithTypes (package:front_end/src/api_prototype/expression_compilation_tools.dart:32:7)
#2 IncrementalCompiler.compileExpression (package:vm/incremental_compiler.dart:219:50)
#3 FrontendCompiler.compileExpression (package:frontend_server/frontend_server.dart:981:45)
#4 listenAndCompile. (package:frontend_server/frontend_server.dart:1452:26)
#5 _RootZone.runUnaryGuarded (dart:async/zone.dart:1594:10)
#6 _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:339:11)
#7 _BufferingStreamSubscription._add (dart:async/stream_impl.dart:271:7)
#8 _SinkTransformerStreamSubscription._add (dart:async/stream_transformers.dart:63:11)
#9 _EventSinkWrapper.add (dart:async/stream_transformers.dart:13:11)
#10 _StringAdapterSink.add (dart:convert/string_conversion.dart:228:11)
#11 _LineSplitterSink._addLines (dart:convert/line_splitter.dart:164:13)
#12 _LineSplitterSink.addSlice (dart:convert/line_splitter.dart:131:7)
#13 StringConversionSink.add (dart:convert/string_conversion.dart:39:5)
#14 _SinkTransformerStreamSubscription._handleData (dart:async/stream_transformers.dart:111:24)
#15 _RootZone.runUnaryGuarded (dart:async/zone.dart:1594:10)
#16 _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:339:11)
#17 _BufferingStreamSubscription._add (dart:async/stream_impl.dart:271:7)
#18 _SinkTransformerStreamSubscription._add (dart:async/stream_transformers.dart:63:11)
#19 _EventSinkWrapper.add (dart:async/stream_transformers.dart:13:11)
#20 _StringAdapterSink.add (dart:convert/string_conversion.dart:228:11)
#21 _StringAdapterSink.addSlice (dart:convert/string_conversion.dart:233:7)
#22 _Utf8ConversionSink.addSlice (dart:convert/string_conversion.dart:307:20)
#23 _Utf8ConversionSink.add (dart:convert/string_conversion.dart:300:5)
#24 _ConverterStreamEventSink.add (dart:convert/chunked_conversion.dart:69:18)
#25 _SinkTransformerStreamSubscription._handleData (dart:async/stream_transformers.dart:111:24)
#26 _RootZone.runUnaryGuarded (dart:async/zone.dart:1594:10)
#27 _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:339:11)
#28 _BufferingStreamSubscription._add (dart:async/stream_impl.dart:271:7)
#29 _SyncStreamControllerDispatch._sendData (dart:async/stream_controller.dart:784:19)
#30 _StreamController._add (dart:async/stream_controller.dart:658:7)
#31 _StreamController.add (dart:async/stream_controller.dart:606:5)
#32 _Socket._onData (dart:io-patch/socket_patch.dart:2447:41)
#33 _RootZone.runUnaryGuarded (dart:async/zone.dart:1594:10)
#34 _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:339:11)
#35 _BufferingStreamSubscription._add (dart:async/stream_impl.dart:271:7)
#36 _SyncStreamControllerDispatch._sendData (dart:async/stream_controller.dart:784:19)
#37 _StreamController._add (dart:async/stream_controller.dart:658:7)
#38 _StreamController.add (dart:async/stream_controller.dart:606:5)
#39 new _RawSocket. (dart:io-patch/socket_patch.dart:1936:33)
#40 _NativeSocket.issueReadEvent.issue (dart:io-patch/socket_patch.dart:1379:14)
#41 _microtaskLoop (dart:async/schedule_microtask.dart:40:21)
#42 _startMicrotaskLoop (dart:async/schedule_microtask.dart:49:5)
#43 _runPendingImmediateCallback (dart:isolate-patch/isolate_patch.dart:123:13)
#44 _RawReceivePort._handleMessage (dart:isolate-patch/isolate_patch.dart:190:5)
the Dart compiler exited unexpectedly.
the Dart compiler exited unexpectedly.

After some debugging, I found out that this crash only happened when I had the debugger on and I created a Future that was only awaited in a later moment of the code. Check this:

Future<void> update() async {
    // userData is a Map that comes from the database
    final anymalsFuture = _updateOwnedAnymals(userData);

    completeName = userData['completeName'];
    cpf = userData['cpf'];
    privacyPolicyAgreement = userData['privacyPolicyAgreement'] != null
        ? PrivacyPolicyAgreement.fromMap(userData['privacyPolicyAgreement'])
        : null;
    if (userData['messagingRegistrationTokens'] != null) {
      messagingRegistrationTokens = List<Map>.from(userData['messagingRegistrationTokens'])
          .map(MessagingRegistrationTokenEntry.fromEntry)
          .toList(growable: false);
    }
    else { messagingRegistrationTokens = []; }
    _updateOrders(userData);
    _updateOwnedCredits(userData);
    _updatePurchases(userData);

    await anymalsFuture;
    _lastUpdated = DateTime.now().millisecondsSinceEpoch;
  }

If the debugger pauses between the creation of the anymalsFuture and its latter await, the compiler will crash. For example, if I put a breakpoint in the line completeName = userData['completeName'];, the crash will happen somewhat 5 seconds after the pause, or when I mouse hover any variable. I am using Android Studio and when I mouse hover any name, the IDE will try to search that name value (if it is a variable) or its documentation (if it is a class/function). Either way, Dart crashes instantly.

If I just awaited that future from the beggining, everything runs normally. I tried to reproduce that with a simple Future.delayed, but no crash occured. This is the _updateOwnedAnymals:

Future<void> _updateOwnedAnymals(Map<String, dynamic> userData) async {
    final ownedSerialKeys = List<String>.from(userData['ownedAnymals']);

    // remove anymals that are not owned by user anymore
    ownedAnymals.removeWhere((anymal) => ! ownedSerialKeys.contains(anymal.serialKey));

    // list of serial keys of anymals that need to be created. Does not include anymals that were created already
    final anymalsToCreate = ownedSerialKeys
        .where((serial) => ! ownedAnymals.any((anymal) => anymal.serialKey == serial));
    final createdAnymals = await Future.wait(anymalsToCreate.map(Anymal.createFromSerial));
    ownedAnymals.addAll(createdAnymals);
}

And the Anymal.createFromSerial is below. Actually, this is supposed to be a constructor. I'm aware that this code is awful; by the time I wrote it I was very newbie. Even so, I don't believe it is so bad that it would crash the compiler.

static Future<Anymal> createFromSerial(String serial) async {
    final anymal = Anymal(serial);

    final infoSnapshot = await FirebaseFirestore.instance.collection('anymals').doc(serial).get();
    final info = infoSnapshot.data();
    if (info == null) { throw 'Could not fetch information on any+ of serial $serial'; }
    anymal._name = info['name'];
    anymal._firstConnected = info['firstConnected'];
    anymal.species = AnymalSpecies.values.byName(info['species']);
    anymal._ownedAddonsCodes = (info['addons'] as List<Object?>).map((addon) => addon?.toString() ?? '').toList();

    anymal.network = NetworkModule(anymal._dbHandler);
    anymal.alarmManager = AlarmModule(anymal._dbHandler);
    anymal.addons = AddonModule(anymal._dbHandler);
    anymal.eyeSettings = EyeSettings(anymal._dbHandler);
    anymal.playback = Playback(anymal._dbHandler);
    anymal.parrotMode = ParrotModeModule(anymal._dbHandler);

    return anymal;
  }

Unfortunately, this is a comercial software so I won't be able to share much more than this. I hope this report could be useful.

dart info

#### General info

• Dart 3.1.3 (stable) (Tue Sep 26 14:25:13 2023 +0000) on "linux_x64"
• on linux / Linux 5.15.0-84-generic Updated bundled libraries will not cause a recompilation of dependent files. #93~20.04.1-Ubuntu SMP Wed Sep 6 16:15:40 UTC 2023
• locale is en_US.UTF-8

Project info

• sdk constraint: '>=2.19.6 <3.0.0'
• dependencies: animations, app_settings, async, cloud_firestore, collection, firebase_auth, firebase_core, firebase_database, firebase_messaging, flutter, flutter_colorpicker, flutter_webrtc, http, qr_code_scanner, skeleton_loader, webview_flutter
• dev_dependencies: flutter_lints, flutter_test

Process info

Memory	CPU	Elapsed time	Command line
33 MB	0.0%	01:09:01	dart devtools --no-launch-browser
32 MB	0.0%	01:06:30	dart devtools --no-launch-browser
34 MB	0.0%	21:45	dart devtools --no-launch-browser
34 MB	0.0%	19:20	dart devtools --no-launch-browser
33 MB	0.0%	14:15	dart devtools --no-launch-browser
33 MB	0.0%	11:04	dart devtools --no-launch-browser
38 MB	0.3%	01:39	dart devtools --no-launch-browser
583 MB	1.0%	45:43	dart language-server --client-id=Android-Studio --client-version=AI-221.6008.13 --protocol=analyzer
75 MB	0.4%	46:48	flutter_tools.snapshot daemon

[npavelko]

I have the same problem

[angelru]

The same issue:

Unhandled exception:
invalid input
#0      parseDefinitionTypes (package:front_end/src/api_prototype/expression_compilation_tools.dart:110:43)
#1      createDefinitionsWithTypes (package:front_end/src/api_prototype/expression_compilation_tools.dart:32:7)
#2      IncrementalCompiler.compileExpression (package:vm/incremental_compiler.dart:219:50)
#3      FrontendCompiler.compileExpression (package:frontend_server/frontend_server.dart:981:45)

#4      listenAndCompile.<anonymous closure> (package:frontend_server/frontend_server.dart:1452:26)
#5      _RootZone.runUnaryGuarded (dart:async/zone.dart:1594:10)
#6      _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:339:11)
#7      _BufferingStreamSubscription._add (dart:async/stream_impl.dart:271:7)
#8      _SinkTransformerStreamSubscription._add (dart:async/stream_transformers.dart:63:11)
#9      _EventSinkWrapper.add (dart:async/stream_transformers.dart:13:11)
#10     _StringAdapterSink.add (dart:convert/string_conversion.dart:228:11)

#11     _LineSplitterSink._addLines (dart:convert/line_splitter.dart:164:13)
#12     _LineSplitterSink.addSlice (dart:convert/line_splitter.dart:131:7)

[Avataromvatar]

The same trouble, but the error is a little different. It always works when you hover over a variable at a breakpoint (in the Future) to look at it. I also tried to repeat the problem in a simple test, but it didn't work out. This started happening quite recently after the update.

Unhandled exception:
FormatException: Invalid radix-10 number (at character 1)
null
^

#0 int._handleFormatError (dart:core-patch/integers_patch.dart:126:5)
#1 int._parseRadix (dart:core-patch/integers_patch.dart:137:16)
#2 int._parse (dart:core-patch/integers_patch.dart:98:12)
#3 int.parse (dart:core-patch/integers_patch.dart:60:12)
#4 parseDefinitionTypes (package:front_end/src/api_prototype/expression_compilation_tools.dart:113:36)
#5 createDefinitionsWithTypes (package:front_end/src/api_prototype/expression_compilation_tools.dart:32:7)
#6 IncrementalCompiler.compileExpression (package:vm/incremental_compiler.dart:219:50)
#7 FrontendCompiler.compileExpression (package:frontend_server/frontend_server.dart:981:45)
#8 listenAndCompile. (package:frontend_server/frontend_server.dart:1452:26)
#9 _RootZone.runUnaryGuarded (dart:async/zone.dart:1594:10)
#10 _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:339:11)
#11 _BufferingStreamSubscription._add (dart:async/stream_impl.dart:271:7)
#12 _SinkTransformerStreamSubscription._add (dart:async/stream_transformers.dart:63:11)
#13 _EventSinkWrapper.add (dart:async/stream_transformers.dart:13:11)
#14 _StringAdapterSink.add (dart:convert/string_conversion.dart:228:11)
#15 _LineSplitterSink._addLines (dart:convert/line_splitter.dart:164:13)
#16 _LineSplitterSink.addSlice (dart:convert/line_splitter.dart:131:7)
#17 StringConversionSink.add (dart:convert/string_conversion.dart:39:5)
#18 _SinkTransformerStreamSubscription._handleData (dart:async/stream_transformers.dart:111:24)
#19 _RootZone.runUnaryGuarded (dart:async/zone.dart:1594:10)
#20 _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:339:11)
#21 _BufferingStreamSubscription._add (dart:async/stream_impl.dart:271:7)
#22 _SinkTransformerStreamSubscription._add (dart:async/stream_transformers.dart:63:11)
#23 _EventSinkWrapper.add (dart:async/stream_transformers.dart:13:11)
#24 _StringAdapterSink.add (dart:convert/string_conversion.dart:228:11)
#25 _StringAdapterSink.addSlice (dart:convert/string_conversion.dart:233:7)
#26 _Utf8ConversionSink.addSlice (dart:convert/string_conversion.dart:307:20)
#27 _Utf8ConversionSink.add (dart:convert/string_conversion.dart:300:5)
#28 _ConverterStreamEventSink.add (dart:convert/chunked_conversion.dart:69:18)
#29 _SinkTransformerStreamSubscription._handleData (dart:async/stream_transformers.dart:111:24)
#30 _RootZone.runUnaryGuarded (dart:async/zone.dart:1594:10)
#31 _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:339:11)
#32 _BufferingStreamSubscription._add (dart:async/stream_impl.dart:271:7)
#33 _SyncStreamControllerDispatch._sendData (dart:async/stream_controller.dart:784:19)
#34 _StreamController._add (dart:async/stream_controller.dart:658:7)
#35 _StreamController.add (dart:async/stream_controller.dart:606:5)
#36 _Socket._onData (dart:io-patch/socket_patch.dart:2447:41)
#37 _RootZone.runUnaryGuarded (dart:async/zone.dart:1594:10)
#38 _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:339:11)
#39 _BufferingStreamSubscription._add (dart:async/stream_impl.dart:271:7)
#40 _SyncStreamControllerDispatch._sendData (dart:async/stream_controller.dart:784:19)
#41 _StreamController._add (dart:async/stream_controller.dart:658:7)
#42 _StreamController.add (dart:async/stream_controller.dart:606:5)
#43 new _RawSocket. (dart:io-patch/socket_patch.dart:1936:33)
#44 _NativeSocket.issueReadEvent.issue (dart:io-patch/socket_patch.dart:1379:14)
#45 _microtaskLoop (dart:async/schedule_microtask.dart:40:21)
#46 _startMicrotaskLoop (dart:async/schedule_microtask.dart:49:5)
#47 _runPendingImmediateCallback (dart:isolate-patch/isolate_patch.dart:123:13)
#48 _RawReceivePort._handleMessage (dart:isolate-patch/isolate_patch.dart:190:5)
the Dart compiler exited unexpectedly.
the Dart compiler exited unexpectedly.

Flutter (Channel stable, 3.13.6, on macOS 14.0 23A344 darwin-arm64, locale en-RU)
• Flutter version 3.13.6 on channel stable at *
• Upstream repository https://github.com/flutter/flutter.git
• Framework revision ead455963c (7 days ago), 2023-09-26 18:28:17 -0700
• Engine revision a794cf2681
• Dart version 3.1.3
• DevTools version 2.25.0

[✓] Android toolchain - develop for Android devices (Android SDK version 33.0.0)
• Android SDK ***
• Platform android-33, build-tools 33.0.0
• Java binary at: /Applications/Android Studio.app/Contents/jbr/Contents/Home/bin/java
• Java version OpenJDK Runtime Environment (build 11.0.15+0-b2043.56-8887301)
• All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 15.0)
• Xcode at ***
• Build 15A240d
• CocoaPods version 1.11.3

[✓] Chrome - develop for the web
• Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 2022.1)
• Android Studio at /Applications/Android Studio.app/Contents
• 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 11.0.15+0-b2043.56-8887301)

[✓] VS Code (version 1.82.3)
• VS Code at /Applications/Visual Studio Code.app/Contents
• Flutter extension version 3.74.0

[JCKodel]

Maybe same here? Dart-Code/Dart-Code#4776

But my code doesn't have any futures at that point (but indeed had some Future<void> stacked on a List to be awaited later with a await Future.wait(list)).

At that specific point in the video, there were no async code executed (at least on my code base).

[johnniwinther]

Likely related to #53382

[johnniwinther]

cc @derekxu16

[derekxu16]

If I run the following Flutter app on an Android emulator using Flutter 3.13.7, set a breakpoint to pause at print(m); and then hover over m, the compiler crashes. If I do the same thing using Flutter from the main channel, the compiler does not crash. So, I think this is a problem you already fixed, @johnniwinther.

import 'dart:collection' show HashMap;

Future<void> _update(Map<String, dynamic> m) async {}

Future<void> main() async {
  final m = HashMap<String, dynamic>();
  final f = _update(m);
  print(m);
  await f;
}

[johnniwinther]

Thanks @derekxu16