HttpContext disposed before the error code is set.

[JunTaoLuo]

Currently in FrameOfT the HttpContext (https://github.com/aspnet/KestrelHttpServer/blob/dev/src/Microsoft.AspNetCore.Server.Kestrel/Http/FrameOfT.cs#L119) is disposed before ProduceEnd() is called (https://github.com/aspnet/KestrelHttpServer/blob/dev/src/Microsoft.AspNetCore.Server.Kestrel/Http/FrameOfT.cs#L133). Disposing of the HttpContext should only happen after Kestrel is really done with it, otherwise we can get into situations where the response on the HttpContext is not correctly set.

For example, we see in aspnet/Hosting#763 when logging the end of the request, the error code is not set correctly to 500:

fail: Microsoft.AspNetCore.Server.Kestrel, Version=1.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60[13]
      Connection id "0HKS2EAGK2HQR": An unhandled exception was thrown by the application.
System.ArgumentException: d
   at WebApplication2.Controllers.ValuesController.Get() in C:\Users\em\Documents\Visual Studio 2015\Projects\WebApplication2\src\WebApplication2\Controllers\ValuesController.cs:line 16
   at lambda_method(Closure , Object , Object[] )
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.<InvokeActionAsync>d__6.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Mvc.Internal.FilterActionInvoker.<InvokeActionFilterAsync>d__41.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at Microsoft.AspNetCore.Mvc.Internal.FilterActionInvoker.<InvokeAsync>d__32.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Mvc.Internal.MvcRouteHandler.<InvokeActionAsync>d__8.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Builder.RouterMiddleware.<Invoke>d__4.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Hosting.Internal.RequestServicesContainerMiddleware.<Invoke>d__3.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Server.Kestrel.Http.Frame`1.<RequestProcessingAsync>d__2.MoveNext()
info: Microsoft.AspNetCore.Hosting.Internal.WebHost[2]
      Request finished in 18.6067ms 200

cc @CesarBS @halter73

[halter73]

@muratg What milestone should this be in? It seems mainly to lead 200 statuses in logs for 500 responses sent by Kestrel caused by uncaught exceptions thrown by the application. This is only an issue if the application hasn't written to the response body prior to throwing.

[muratg]

I think we can get to this post RTM.