The underlying Task is already in one of the three final states: RanToCompletion, Faulted, or Canceled.

[oliverw]

Occurs from time to time in AFNetworkHandler.cs:87 and I haven't yet figured why and when. But brings down the application when it occurs.

2013-10-05 20:53:29.961 GIFE[17563:c07] Unhandled managed exception: The underlying Task is already in one of the three final states: RanToCompletion, Faulted, or Canceled. (System.InvalidOperationException)
  at System.Threading.Tasks.TaskCompletionSource`1[AFNetworking.AFHTTPRequestOperation].ThrowInvalidException () [0x00000] in /Developer/MonoTouch/Source/mono/mcs/class/corlib/System.Threading.Tasks/TaskCompletionSource.cs:91 
  at System.Threading.Tasks.TaskCompletionSource`1[AFNetworking.AFHTTPRequestOperation].SetException (IEnumerable`1 exceptions) [0x0000c] in /Developer/MonoTouch/Source/mono/mcs/class/corlib/System.Threading.Tasks/TaskCompletionSource.cs:80 
  at System.Threading.Tasks.TaskCompletionSource`1[AFNetworking.AFHTTPRequestOperation].SetException (System.Exception exception) [0x00011] in /Developer/MonoTouch/Source/mono/mcs/class/corlib/System.Threading.Tasks/TaskCompletionSource.cs:74 
  at ModernHttpClient.AFNetworkHandler+<enqueueOperation>c__AnonStorey2.<>m__1 (AFNetworking.AFHTTPRequestOperation op, MonoTouch.Foundation.NSError err) [0x00037] in /Users/oliver/Projects/ModernHttpClient/src/ModernHttpClient.iOS/AFNetworkHandler.cs:87 
  at MonoTouch.ObjCRuntime.Trampolines+SDAFHttpRequestFailureCallback.Invoke (IntPtr block, IntPtr operation, IntPtr error) [0x00061] in /Users/oliver/Projects/ModernHttpClient/vendor/afnetworking/AFNetworking/obj/Debug/ios/ObjCRuntime/Trampolines.g.cs:185 
  at (wrapper native-to-managed) MonoTouch.ObjCRuntime.Trampolines/SDAFHttpRequestFailureCallback:Invoke (intptr,intptr,intptr)
  at (wrapper managed-to-native) MonoTouch.UIKit.UIApplication:UIApplicationMain (int,string[],intptr,intptr)
  at MonoTouch.UIKit.UIApplication.Main (System.String[] args, System.String principalClassName, System.String delegateClassName) [0x0004c] in /Developer/MonoTouch/Source/monotouch/src/UIKit/UIApplication.cs:38 
  at GIFE.Application.Main (System.String[] args) [0x00009] in /Users/oliver/Projects/GIFE/IOS/GIFE/Main.cs:18 

[anaisbetts]

Think b689234 takes care of this but I have no idea, can you give it a shot?

[oliverw]

Could have been caused by using this overload:

SendAsync(msg, HttpCompletionOption.ResponseHeadersRead)

[alexshikov]

I do experience the same issue.

I didn't figure out the reason of the issue yet, but the fix is simple:
change SetResult, SetException, SetCanceled inside the method enqueueOperation
to TrySetResult, TrySetException, TrySetCanceled

I believe b689234 can be reverted then.

[anaisbetts]

This should be fixed now, reopen it if it's not