Hi All – I’m trying to use the withSideEffect() configuration to add a list of maps to GraphTraversalSource like is done in the Long Traversals recipe and the server throws an exception – “Could not deserialize the Traversal instance java.lang.IllegalStateException: Could not locate method: GraphTraversalSource.withSideEffect(String, LinkedHashMap, LinkedHashMap)”

The .NET code that reproduces the error:

var server = new GremlinServer("localhost", port: 8182);

var client = JanusGraphClientBuilder.BuildClientForServer(server).Create();

using var connection = new DriverRemoteConnection(client);

var g = AnonymousTraversalSource.Traversal().WithRemote(connection);

var xxx = new[]

{

  new Dictionary<object, object> { { "x", 1 }, { "y", 2 } },

  new Dictionary<object, object> { { "x", 3 }, { "y", 4 } }

};

await g.WithSideEffect("xxx", xxx).V().Promise(t => t.ToList());

The same result is produced using an array of strongly typed objects:

public class XXX

{

  public int X { get; init; }

  public int Y { get; init; }

}

var server = new GremlinServer("localhost", port: 8182);

var client = JanusGraphClientBuilder.BuildClientForServer(server).Create();

using var connection = new DriverRemoteConnection(client);

var g = AnonymousTraversalSource.Traversal().WithRemote(connection);

var xxx = new[] { new XXX { X = 1, Y = 2 }, new XXX { X = 3, Y = 4 } };

await g.WithSideEffect("xxx", xxx).V().Promise(t => t.ToList());

However, the “inject” step works fine passing an array of maps:

await g.Inject<object>(xxx).Promise(t => t.ToList());

Invoking “withSideEffect” produces the following error on the server:

ERROR org.apache.tinkerpop.gremlin.server.op.traversal.TraversalOpProcessor  - Could not deserialize the Traversal instance

java.lang.IllegalStateException: Could not locate method: GraphTraversalSource.withSideEffect(String, LinkedHashMap, LinkedHashMap)

        at org.apache.tinkerpop.gremlin.jsr223.JavaTranslator.invokeMethod(JavaTranslator.java:300)

        at org.apache.tinkerpop.gremlin.jsr223.JavaTranslator.translate(JavaTranslator.java:85)

        at org.apache.tinkerpop.gremlin.server.op.traversal.TraversalOpProcessor.iterateBytecodeTraversal(TraversalOpProcessor.java:181)

        at org.apache.tinkerpop.gremlin.server.handler.OpExecutorHandler.channelRead0(OpExecutorHandler.java:67)

        at org.apache.tinkerpop.gremlin.server.handler.OpExecutorHandler.channelRead0(OpExecutorHandler.java:43)

        at io.netty.channel.SimpleChannelInboundHandler.channelRead(SimpleChannelInboundHandler.java:99)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.channel.ChannelInboundHandlerAdapter.channelRead(ChannelInboundHandlerAdapter.java:93)

        at io.netty.handler.codec.http.websocketx.Utf8FrameValidator.channelRead(Utf8FrameValidator.java:82)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:324)

        at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:296)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.handler.timeout.IdleStateHandler.channelRead(IdleStateHandler.java:286)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919)

        at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:166)

        at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:722)

        at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:658)

        at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:584)

        at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:496)

        at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:986)

        at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)

        at java.lang.Thread.run(Thread.java:750)

31637 [gremlin-server-worker-1] WARN  org.apache.tinkerpop.gremlin.server.handler.OpExecutorHandler  - Could not deserialize the Traversal instance

org.apache.tinkerpop.gremlin.server.op.OpProcessorException: Could not deserialize the Traversal instance

        at org.apache.tinkerpop.gremlin.server.op.traversal.TraversalOpProcessor.iterateBytecodeTraversal(TraversalOpProcessor.java:195)

        at org.apache.tinkerpop.gremlin.server.handler.OpExecutorHandler.channelRead0(OpExecutorHandler.java:67)

        at org.apache.tinkerpop.gremlin.server.handler.OpExecutorHandler.channelRead0(OpExecutorHandler.java:43)

        at io.netty.channel.SimpleChannelInboundHandler.channelRead(SimpleChannelInboundHandler.java:99)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.channel.ChannelInboundHandlerAdapter.channelRead(ChannelInboundHandlerAdapter.java:93)

        at io.netty.handler.codec.http.websocketx.Utf8FrameValidator.channelRead(Utf8FrameValidator.java:82)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:324)

        at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:296)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.handler.timeout.IdleStateHandler.channelRead(IdleStateHandler.java:286)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919)

        at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:166)

        at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:722)

        at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:658)

        at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:584)

        at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:496)

        at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:986)

        at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)

        at java.lang.Thread.run(Thread.java:750)

Is this a bug, or am I doing something wrong?

- Bill

This sounds like a bug in Gremlin.Net to me, especially since it’s working with the Inject() step. Could you please create an issue with the TinkerPop (to which Gremlin.Net belongs) project here: https://issues.apache.org/jira/browse/TINKERPOP/ ?

Your second example with your own class XXX however cannot work as Gremlin.Net and Gremlin Server / JanusGraph Server cannot know how to serialize / deserialize this type. You would need to write your own serializer and deserializer for this type to make it work.

Hi All – I’m trying to use the withSideEffect() configuration to add a list of maps to GraphTraversalSource like is done in the Long Traversals recipe and the server throws an exception – “Could not deserialize the Traversal instance java.lang.IllegalStateException: Could not locate method: GraphTraversalSource.withSideEffect(String, LinkedHashMap, LinkedHashMap)”

The .NET code that reproduces the error:

var server = new GremlinServer("localhost", port: 8182);

var client = JanusGraphClientBuilder.BuildClientForServer(server).Create();

using var connection = new DriverRemoteConnection(client);

var g = AnonymousTraversalSource.Traversal().WithRemote(connection);

var xxx = new[]

{

  new Dictionary<object, object> { { "x", 1 }, { "y", 2 } },

  new Dictionary<object, object> { { "x", 3 }, { "y", 4 } }

};

await g.WithSideEffect("xxx", xxx).V().Promise(t => t.ToList());

The same result is produced using an array of strongly typed objects:

public class XXX

{

  public int X { get; init; }

  public int Y { get; init; }

}

var server = new GremlinServer("localhost", port: 8182);

var client = JanusGraphClientBuilder.BuildClientForServer(server).Create();

using var connection = new DriverRemoteConnection(client);

var g = AnonymousTraversalSource.Traversal().WithRemote(connection);

var xxx = new[] { new XXX { X = 1, Y = 2 }, new XXX { X = 3, Y = 4 } };

await g.WithSideEffect("xxx", xxx).V().Promise(t => t.ToList());

However, the “inject” step works fine passing an array of maps:

await g.Inject<object>(xxx).Promise(t => t.ToList());

Invoking “withSideEffect” produces the following error on the server:

ERROR org.apache.tinkerpop.gremlin.server.op.traversal.TraversalOpProcessor  - Could not deserialize the Traversal instance

java.lang.IllegalStateException: Could not locate method: GraphTraversalSource.withSideEffect(String, LinkedHashMap, LinkedHashMap)

        at org.apache.tinkerpop.gremlin.jsr223.JavaTranslator.invokeMethod(JavaTranslator.java:300)

        at org.apache.tinkerpop.gremlin.jsr223.JavaTranslator.translate(JavaTranslator.java:85)

        at org.apache.tinkerpop.gremlin.server.op.traversal.TraversalOpProcessor.iterateBytecodeTraversal(TraversalOpProcessor.java:181)

        at org.apache.tinkerpop.gremlin.server.handler.OpExecutorHandler.channelRead0(OpExecutorHandler.java:67)

        at org.apache.tinkerpop.gremlin.server.handler.OpExecutorHandler.channelRead0(OpExecutorHandler.java:43)

        at io.netty.channel.SimpleChannelInboundHandler.channelRead(SimpleChannelInboundHandler.java:99)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.channel.ChannelInboundHandlerAdapter.channelRead(ChannelInboundHandlerAdapter.java:93)

        at io.netty.handler.codec.http.websocketx.Utf8FrameValidator.channelRead(Utf8FrameValidator.java:82)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:324)

        at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:296)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.handler.timeout.IdleStateHandler.channelRead(IdleStateHandler.java:286)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919)

        at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:166)

        at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:722)

        at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:658)

        at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:584)

        at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:496)

        at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:986)

        at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)

        at java.lang.Thread.run(Thread.java:750)

31637 [gremlin-server-worker-1] WARN  org.apache.tinkerpop.gremlin.server.handler.OpExecutorHandler  - Could not deserialize the Traversal instance

org.apache.tinkerpop.gremlin.server.op.OpProcessorException: Could not deserialize the Traversal instance

        at org.apache.tinkerpop.gremlin.server.op.traversal.TraversalOpProcessor.iterateBytecodeTraversal(TraversalOpProcessor.java:195)

        at org.apache.tinkerpop.gremlin.server.handler.OpExecutorHandler.channelRead0(OpExecutorHandler.java:67)

        at org.apache.tinkerpop.gremlin.server.handler.OpExecutorHandler.channelRead0(OpExecutorHandler.java:43)

        at io.netty.channel.SimpleChannelInboundHandler.channelRead(SimpleChannelInboundHandler.java:99)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.channel.ChannelInboundHandlerAdapter.channelRead(ChannelInboundHandlerAdapter.java:93)

        at io.netty.handler.codec.http.websocketx.Utf8FrameValidator.channelRead(Utf8FrameValidator.java:82)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:324)

        at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:296)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.handler.timeout.IdleStateHandler.channelRead(IdleStateHandler.java:286)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919)

        at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:166)

        at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:722)

        at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:658)

        at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:584)

        at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:496)

        at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:986)

        at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)

        at java.lang.Thread.run(Thread.java:750)

Is this a bug, or am I doing something wrong?

- Bill

Thanks Florian. I’ve created the issue with TinkerPop here.

You said that using my own class XXX cannot work, but strangely it seems to with the following code showing the injected array of XXX objects being successfully returned from the server:

var xxx = new[] { new XXX { X = 1, Y = 2 }, new XXX { X = 3, Y = 4 } };

var result = (List<object>)await g.Inject<object>(xxx).Promise(t => t.ToList());

foreach (var x in result)

{

  foreach (var pair in (Dictionary<object, object>)x)

  {

   Console.WriteLine($"{pair.Key}: {pair.Value}");

  }

}

… which displays:

X: 1

Y: 2

X: 3

Y: 4

Oh wow, I assumed that Gremlin.Net would throw if it has no GraphSON serializer for a given type but turns out that it just provides the object unchanged to the JsonSerializer from System.Text.Json which results in a JSON serialization that is not strongly typed like it should be with GraphSON. This is the result for your example:

{"@type":"g:List","@value":[{"X":1,"Y":2},{"X":3,"Y":4}]}

I’m not sure if this is a bug or a feature to be honest, but this sentence from the GraphSON 3 spec at least sounds like this shouldn’t be possible:

“GraphSON 3.0 does not have an option to be typeless. Types are always embedded except for strings and boolean values which are inferred from JSON types.”

https://tinkerpop.apache.org/docs/current/dev/io/#graphson-3d0

I created another issue for this: https://issues.apache.org/jira/browse/TINKERPOP-2788

Thanks Florian. I’ve created the issue with TinkerPop here.

You said that using my own class XXX cannot work, but strangely it seems to with the following code showing the injected array of XXX objects being successfully returned from the server:

var xxx = new[] { new XXX { X = 1, Y = 2 }, new XXX { X = 3, Y = 4 } };

var result = (List<object>)await g.Inject<object>(xxx).Promise(t => t.ToList());

foreach (var x in result)

{

  foreach (var pair in (Dictionary<object, object>)x)

  {

   Console.WriteLine($"{pair.Key}: {pair.Value}");

  }

}

… which displays:

X: 1

Y: 2

X: 3

Y: 4