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NullReferenceException when api return null result.

See original GitHub issue

To Reproduce

Steps to reproduce the behavior:

create an asp.net api project with version 2.2
add code

   [Route("api/[controller]")]
   [ApiController]
   public class ValuesController : ControllerBase
   {
     [Route("test")]
       public Task<string> Testapi()
       {           
               return null;
       }
     }

test the api with browser
it returns error


NullReferenceException: Object reference not set to an instance of an object.
lambda_method(Closure , object )
Microsoft.Extensions.Internal.ObjectMethodExecutorAwaitable.GetAwaiter()
Microsoft.AspNetCore.Mvc.Internal.ActionMethodExecutor+AwaitableObjectResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, object controller, object[] arguments)
System.Threading.Tasks.ValueTask<TResult>.get_Result()
Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.InvokeActionMethodAsync()
Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.InvokeNextActionFilterAsync()
Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Rethrow(ActionExecutedContext context)
Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Next(ref State next, ref Scope scope, ref object state, ref bool isCompleted)
Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.InvokeInnerFilterAsync()
Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeNextResourceFilter()
Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Rethrow(ResourceExecutedContext context)
Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Next(ref State next, ref Scope scope, ref object state, ref bool isCompleted)
Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeFilterPipelineAsync()
Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeAsync()
Microsoft.AspNetCore.Routing.EndpointMiddleware.Invoke(HttpContext httpContext)
Microsoft.AspNetCore.Routing.EndpointRoutingMiddleware.Invoke(HttpContext httpContext)

Expected behavior

NullReferenceException should be handled propertly and return some useful information.

Issue Analytics

State:
Created 4 years ago
Comments:8 (8 by maintainers)

Top GitHub Comments

1reaction

rynowakcommented, Jun 5, 2019

I suspect that what’s happening here is the action is throwing and your error handler is what’s returning a 404.

0reactions

mkArtakMSFTcommented, Jun 5, 2019

So looks like I referred to something which we never did. So I’m removing my statement above regarding 3.0 to avoid spreading wrong information out. I had a chat with @rynowak regarding this and what is most probably happening in your case is you’re hitting the same exception as you do in 2.2, but… (and @rynowak just responded 😃 )

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