[TINKERPOP-2192] Gremlin.Net.Driver.Connection.Parse throws a NullReferenceException

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 3.4.1
• Fix Version/s: 3.5.0, 3.4.7
• Component/s: dotnet
• Assignee: Unassigned
• Reporter: Florian Hockmann
• Created: 04/Apr/19 14:42
• Updated: 06/Mar/20 13:40
• Resolved: 06/Mar/20 13:40

Description

The Parse method has only three objects on which we call methods of which two are readonly. So the problem is most likely in the error handling:

if (_callbackByRequestId.TryRemove(receivedMsg.RequestId, out var responseHandler))
 {
     responseHandler.HandleFailure(e);
}
 

Here, responseHandler can be null if the callback handler for that request id was not found. So we just need a null check. (We can't notify anyone about a failure any way in this case.)

Stack trace:

System.NullReferenceException: Object reference not set to an instance of an object.
   at Gremlin.Net.Driver.Connection.Parse(Byte[] received)
   at Gremlin.Net.Driver.Connection.ReceiveMessagesAsync()
   at Gremlin.Net.Driver.ProxyConnection.SubmitAsync[T](RequestMessage requestMessage)
   at Gremlin.Net.Driver.GremlinClient.SubmitAsync[T](RequestMessage requestMessage)
   at Gremlin.Net.Driver.Remote.DriverRemoteConnection.SubmitBytecodeAsync(Guid requestid, Bytecode bytecode)
   at Gremlin.Net.Driver.Remote.DriverRemoteConnection.SubmitAsync[S,E](Bytecode bytecode)
   at Gremlin.Net.Process.Remote.RemoteStrategy.ApplyAsync[S,E](ITraversal`2 traversal)
   at Gremlin.Net.Process.Traversal.DefaultTraversal`2.ApplyStrategiesAsync()
   at Gremlin.Net.Process.Traversal.DefaultTraversal`2.Promise[TReturn](Func`2 callback)
 

Issue Links

• is duplicated by: TINKERPOP-2304 gremlin.net System.NullReferenceException on SubmitAsync in iOS platform
• links to: GitHub Pull Request #1247
• links to: GitHub Pull Request #1250
• links to: GitHub Pull Request #1258