Stack overflow when reading data

[timk10]

We run into stack overflow error due to handleBody/handleHeader calling itself repeatedly (see stacktrace)

Socket error Stack Overflow #0 List.setRange (dart:core-patch/array.dart:31) #1 PacketConverter._readPacketIntoBuffer (package:plato_mongo_dart/src/network/packet_converter.dart:72:12) #2 PacketConverter.handleBody (package:plato_mongo_dart/src/network/packet_converter.dart:63:19) #3 PacketConverter.handleHeader (package:plato_mongo_dart/src/network/packet_converter.dart:37:7) #4 PacketConverter.handleBody (package:plato_mongo_dart/src/network/packet_converter.dart:48:7) #5 PacketConverter.handleHeader (package:plato_mongo_dart/src/network/packet_converter.dart:37:7) #6 PacketConverter.handleBody (package:plato_mongo_dart/src/network/packet_converter.dart:48:7) #7 PacketConverter.handleHeader (package:plato_mongo_dart/src/network/packet_converter.dart:37:7) #8 PacketConverter.handleBody (package:plato_mongo_dart/src/network/packet_converter.dart:48:7) #9 PacketConverter.handleHeader (package:plato_mongo_dart/src/network/packet_converter.dart:37:7) #10 PacketConverter.handleBody (package:plato_mongo_dart/src/network/packet_converter.dart:48:7) #11 PacketConverter.handleHeader (package:plato_mongo_dart/src/network/packet_converter.dart:37:7) #12 PacketConverter.handleBody (package:plato_mongo_dart/src/network/packet_converter.dart:48:7) #13 PacketConverter.handleHeader (package:plato_mongo_dart/src/network/packet_converter.dart:37:7) ... ... #14864 _StreamController.add (dart:async/stream_controller.dart:603) #14865 _Socket._onData (dart:io-patch/socket_patch.dart:1617) #14866 StackZoneSpecification._registerUnaryCallback.<anonymous closure>.<anonymous closure> (package:stack_trace/src/stack_zone_specification.dart) #14867 StackZoneSpecification._run (package:stack_trace/src/stack_zone_specification.dart) #14868 StackZoneSpecification._registerUnaryCallback.<anonymous closure> (package:stack_trace/src/stack_zone_specification.dart:107:14) #14869 _rootRunUnary (dart:async/zone.dart) #14870 _CustomZone.runUnaryGuarded (dart:async/zone.dart) #14871 _StreamController.add (dart:async/stream_controller.dart:603) #14872 new _RawSocket.<anonymous closure> (dart:io-patch/socket_patch.dart:1203) #14873 _NativeSocket.issueReadEvent.issue (dart:io-patch/socket_patch.dart) #14874 _startMicrotaskLoop (dart:async/schedule_microtask.dart) #14875 _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart)

Upon reading the code it seems if there are more than 7400+ messages in a single packet (back of napkin calculation: based on the # of stacks, around 14864/2 ~ 7432 messages) then it would cause the 2 functions calling each other until stack overflow.

Seems there could be 2 scenarios

1. If Mongo decides to send a packet with many messages.
2. It's also possible that Dart batches all the messages into a single packet.

I'm not able to reproduce it locally, but I do see it happen quite often in production so I'm not able to nail down which of the above scenarios caused the issue.

Is there a reason why we choose to read the packets recursively?
Should we handle reading of the packets in iterative manner rather than recursive?

[Pacane]

Sorry, is this really a mongo_dart issue? I don't see any line in the stacktrace that belongs to mongo_dart?

[timk10]

Sorry, we forked a version of it so that we could reconnect if there were socket error Change is here: (timk10@9070d7e).

However rest of the code is still the same.