Obscure NullReferenceException if server does not provide a Content-Type header in polling transport

[vsoldatkin]

You'll get a null reference here: https://github.com/Quobject/EngineIoClientDotNet/blob/master/Src/EngineIoClientDotNet.mono/Client/Transports/PollingXHR.cs#L328

It is accessed later in an octet-stream check producing a NullReferenceException which is quite hard to grasp using a release nuget build.

[mattqs]

Why is it hard to grasp?

[vsoldatkin]

If someone uses a release build published in nuget he gets no info about the exception at all, which makes it impossible to know what exatcly went wrong and how one should fix that.

Aside of that, do you by closing this issue mean you don't acknowlege this as a bug? I'm not talking about the obscurity, it is about the exception while processing the response with no header. Note that Content-Type header is optional.

[mattqs]

OK, Reopened. Please provide a stacktrace.

[vsoldatkin]

This is what the immediate call stack looks like (via IntelliTrace):

>   EngineIoClientDotNet.dll!XHRRequest.AnonymousMethod()   
    mscorlib.dll!System.Threading.Tasks.Task.InnerInvoke()  
    mscorlib.dll!System.Threading.Tasks.Task.Execute()  
    mscorlib.dll!System.Threading.Tasks.Task.ExecutionContextCallback(object obj = {unknown})   
    mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext = {unknown}, System.Threading.ContextCallback callback = {unknown}, object state = {unknown}, bool preserveSyncCtx = {unknown})   
    mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext = {unknown}, System.Threading.ContextCallback callback = {unknown}, object state = {unknown}, bool preserveSyncCtx = {unknown})   
    mscorlib.dll!System.Threading.Tasks.Task.ExecuteWithThreadLocal(ref System.Threading.Tasks.Task currentTaskSlot = {unknown})    
    mscorlib.dll!System.Threading.Tasks.Task.ExecuteEntry(bool bPreventDoubleExecution = {unknown}) 
    mscorlib.dll!System.Threading.Tasks.Task.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem() 
    mscorlib.dll!System.Threading.ThreadPoolWorkQueue.Dispatch()    
    mscorlib.dll!System.Threading._ThreadPoolWaitCallback.PerformWaitCallback() 

Here is an error message from the Socket.IO connect_error handler:

Quobject.EngineIoClientDotNet.Client.EngineIOException: xhr poll error ---> System.AggregateException ---> System.NullReferenceException
   в Quobject.EngineIoClientDotNet.Client.Transports.PollingXHR.XHRRequest.<Create>b__2()
   в System.Threading.Tasks.Task.InnerInvoke()
   в System.Threading.Tasks.Task.Execute()
   --- End of inner exception stack trace ---
   в System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
   в System.Threading.Tasks.Task.Wait(Int32 millisecondsTimeout, CancellationToken cancellationToken)
   в System.Threading.Tasks.Task.Wait()
   в Quobject.EngineIoClientDotNet.Client.Transports.PollingXHR.XHRRequest.Create()
   --- End of inner exception stack trace ---

Not really informative, aren't they? The exact cause is provided in the first post.