Logging integration behaviour when message is Object is inconsistent with the Logging package

[maBarabas]

Platform

Dart

Obfuscation

Enabled

Debug Info

Enabled

Doctor

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    • Framework revision f468f3366c (3 weeks ago), 2023-07-12 15:19:05 -0700
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! Doctor found issues in 1 category.

Version

7.9.0

Steps to Reproduce

1. Set up an app with Sentry and logging integration
2. Log an object: Logger('test').info(DemoObject());

class DemoObject {
  final int answer = 42;

  @override
  String toString() {
    return 'DemoObject: $answer';
  }
}

Expected Result

Sentry creates a breadcrumb from the log that matches the output of the app's logger.

Actual Result

Sentry drops the breadcrumb with an exception.

[sentry] [error] Native call `addBreadcrumb` failed
         Invalid argument: Instance of 'DemoObject'
         #0      StandardMessageCodec.writeValue (package:flutter/src/services/message_codecs.dart:465:7)
         #1      StandardMessageCodec.writeValue.<anonymous closure> (package:flutter/src/services/message_codecs.dart:462:9)
         #2      _LinkedHashMapMixin.forEach (dart:collection-patch/compact_hash.dart:625:13)
         #3      StandardMessageCodec.writeValue (package:flutter/src/services/message_codecs.dart:460:13)
         #4      StandardMessageCodec.writeValue.<anonymous closure> (package:flutter/src/services/message_codecs.dart:462:9)
         #5      _LinkedHashMapMixin.forEach (dart:collection-patch/compact_hash.dart:625:13)
         #6      StandardMessageCodec.writeValue (package:flutter/src/services/message_codecs.dart:460:13)
         #7      StandardMessageCodec.writeValue.<anonymous closure> (package:flutter/src/services/message_codecs.dart:462:9)
         #8      _LinkedHashMapMixin.forEach (dart:collection-patch/compact_hash.dart:625:13)
         #9      StandardMessageCodec.writeValue (package:flutter/src/services/message_codecs.dart:460:13)
         #10     StandardMethodCodec.encodeMethodCall (package:flutter/src/services/message_codecs.dart:603:18)
         #11     MethodChannel._invokeMethod (package:flutter/src/services/platform_channel.dart:299:34)
         #12     MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:483:12)
         #13     SentryNativeChannel.addBreadcrumb (package:sentry_flutter/src/sentry_native_channel.dart:59:12)
         #14     SentryNative.addBreadcrumb (package:sentry_flutter/src/sentry_native.dart:72:34)
         #15     NativeScopeObserver.addBreadcrumb (package:sentry_flutter/src/native_scope_observer.dart:29:25)
         #16     Scope.addBreadcrumb.<anonymous closure> (package:sentry/src/scope.dart:195:31)
         #17     Scope._callScopeObservers (package:sentry/src/scope.dart:455:21)
         #18     Scope.addBreadcrumb (package:sentry/src/scope.dart:194:13)
         #19     Hub.addBreadcrumb (package:sentry/src/hub.dart:293:24)
         #20     Sentry.addBreadcrumb (package:sentry/src/sentry.dart:233:12)
         #21     HubAdapter.addBreadcrumb (package:sentry/src/hub_adapter.dart:30:20)
         #22     LoggingIntegration._onLog (package:sentry_logging/src/logging_integration.dart:66:18)
         #23     _RootZone.runUnaryGuarded (dart:async/zone.dart:1594:10)
         #24     _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:339:11)
         #25     _BufferingStreamSubscription._add (dart:async/stream_impl.dart:271:7)
         #26     _SyncBroadcastStreamController._sendData.<anonymous closure> (dart:async/broadcast_stream_controller.dart:385:20)
         #27     _BroadcastStreamController._forEachListener (dart:async/broadcast_stream_controller.dart:322:15)
         #28     _SyncBroadcastStreamController._sendData (dart:async/broadcast_stream_controller.dart:384:5)
         #29     _BroadcastStreamController.add (dart:async/broadcast_stream_controller.dart:244:5)
         #30     Logger._publish (package:logging/src/logger.dart:287:51)
         #31     Logger.log (package:logging/src/logger.dart:215:18)
         #32     Logger.info (package:logging/src/logger.dart:255:7)
         #33     appMain (package:maestrounite/main.dart:102:8)
         #34     Sentry._init (package:sentry/src/sentry.dart:149:24)
         <asynchronous suspension>
         #35     Sentry.init (package:sentry/src/sentry.dart:70:5)
         <asynchronous suspension>
         #36     SentryFlutter.init (package:sentry_flutter/src/sentry_flutter.dart:83:5)
         <asynchronous suspension>
         #37     main (package:maestrounite/main.dart:69:3)
         <asynchronous suspension>

It seems like the caller of StandardMessageCodec.writeValue should call toString() before passing the Object?

Are you willing to submit a PR?

None

[maBarabas]

I think this is the root cause:

Breadcrumb.toJson returns invalid Dart JSON map, containing the instance of the class passed to the logger. I think this map should only contain the well known JSON types that are used in Dart. i.e. Map<String, dynamic>, with the dynamic representing int, double, List or Map. Any other type can get turned into a String. Altough this doesn't make a lot of sense, as the string version of the object is already available in the message field.

[krystofwoldrich]

Hi,
thank you for the message, you point out the cause correctly, the issue is with the object not being known JSON type.

Related Breadcrumb.toJson code.

sentry-dart/dart/lib/src/protocol/breadcrumb.dart

Lines 179 to 190 in d783424

	/// Converts this breadcrumb to a map that can be serialized to JSON according
	/// to the Sentry protocol.
	Map<String, dynamic> toJson() {
	return {
	'timestamp': formatDateAsIso8601WithMillisPrecision(timestamp),
	if (message != null) 'message': message,
	if (category != null) 'category': category,
	if (data?.isNotEmpty ?? false) 'data': data,
	if (level != null) 'level': level!.name,
	if (type != null) 'type': type,
	};
	}

[marandaneto]

That is a bug when calling the Native bridge and syncing data, thanks for raising this.

Instead of fixing this only for crumbs, I'd rather do something similar to

sentry-dart/dart/lib/src/utils.dart

Lines 27 to 36 in d783424

	@internal
	final utf8JsonEncoder = JsonUtf8Encoder(null, jsonSerializationFallback, null);
	@internal
	Object? jsonSerializationFallback(Object? nonEncodable) {
	if (nonEncodable == null) {
	return null;
	}
	return nonEncodable.toString();
	}

but for Map, so the bridge is always called with a valid Map.

The code that fallback to toString should be applied for every data class that is converted to Map and calls the NativeScopeObserver/SentryNativeChannel.
This is only necessary when the data class has a Map with a non-validated field, eg Object or dynamic or any type that is not serializable.

[marandaneto]

Ideally, https://github.com/flutter/flutter/blob/ad0aa8de75120f532463e493d5671cb72354250b/packages/flutter/lib/src/services/message_codecs.dart#L464 would fallback to toString but it's not the case.

[marandaneto]

@ueman shared a code snippet:

jsonDecode(jsonEncode(obj.toJson(), toEncodable: jsonSerializationFallback))

This will make it serializable but it has the cost to do a serialization roundtrip.
Let's check if it's possible to just normalize the Map first.