[Fixes #3928] Ensure we throw at UseMvc during application startup if…

… AddMvc wasn't called

src/Microsoft.AspNet.Mvc.Core/Builder/MvcApplicationBuilderExtensions.cs

@@ -2,10 +2,12 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using Microsoft.AspNet.Mvc.Core;
 using Microsoft.AspNet.Mvc.Infrastructure;
 using Microsoft.AspNet.Mvc.Internal;
 using Microsoft.AspNet.Mvc.Routing;
 using Microsoft.AspNet.Routing;
+using Microsoft.Extensions.DependencyInjection;
 
 namespace Microsoft.AspNet.Builder
 {
@@ -77,7 +79,15 @@ public static IApplicationBuilder UseMvc(
 
             // Verify if AddMvc was done before calling UseMvc
             // We use the MvcMarkerService to make sure if all the services were added.
-            MvcServicesHelper.ThrowIfMvcNotRegistered(app.ApplicationServices);
+            if (app.ApplicationServices.GetService(typeof(MvcMarkerService)) == null)
+            {
+                throw new InvalidOperationException(Resources.FormatUnableToFindServices(
+                    nameof(IServiceCollection),
+                    "AddMvc",
+                    nameof(IServiceCollection),
+                    nameof(MvcCoreServiceCollectionExtensions.AddMvcCore),
+                    "ConfigureServices(...)"));
+            }
 
             var routes = new RouteBuilder(app)
             {

src/Microsoft.AspNet.Mvc.Core/Infrastructure/MvcRouteHandler.cs

@@ -119,10 +119,6 @@ private void EnsureServices(HttpContext context)
 
             var services = context.RequestServices;
 
-            // Verify if AddMvc was done before calling UseMvc
-            // We use the MvcMarkerService to make sure if all the services were added.
-            MvcServicesHelper.ThrowIfMvcNotRegistered(services);
-
             // The IActionContextAccessor is optional. We want to avoid the overhead of using CallContext
             // if possible.
             _actionContextAccessor = services.GetService<IActionContextAccessor>();

src/Microsoft.AspNet.Mvc.Core/Internal/MvcMarkerService.cs

@@ -1,11 +1,13 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using Microsoft.Extensions.DependencyInjection;
+
 namespace Microsoft.AspNet.Mvc.Internal
 {
     /// <summary>
-    /// This is a Marker class which is used to determine if all the services were added
-    /// to when Mvc is loaded.
+    /// A marker class used to determine if all the MVC services were added
+    /// to the <see cref="IServiceCollection"/> before MVC is configured.
     /// </summary>
     public class MvcMarkerService
     {

src/Microsoft.AspNet.Mvc.Core/Resources.resx

@@ -208,7 +208,7 @@
     <value>An unescaped '[' token is not allowed inside of a replacement token. Use '[[' to escape.</value>
   </data>
   <data name="UnableToFindServices" xml:space="preserve">
-    <value>Unable to find the required services. Please add all the required services by calling '{0}' inside the call to '{1}' or '{2}' in the application startup code.</value>
+    <value>Unable to find the required services. Please add all the required services by calling '{0}.{1}' or '{2}.{3}' inside the call to '{4}' in the application startup code.</value>
   </data>
   <data name="AttributeRoute_DuplicateNames_Item" xml:space="preserve">
     <value>Action: '{0}' - Template: '{1}'</value>

test/Microsoft.AspNet.Mvc.Core.Test/Builder/MvcApplicationBuilderExtensionsTest.cs

@@ -0,0 +1,33 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using Microsoft.AspNet.Builder;
+using Moq;
+using Xunit;
+
+namespace Microsoft.AspNet.Mvc.Core.Builder
+{
+    public class MvcApplicationBuilderExtensionsTest
+    {
+        [Fact]
+        public void UseMvc_ThrowsInvalidOperationException_IfRoutingMarkerServiceIsNotRegistered()
+        {
+            // Arrange
+            var applicationBuilderMock = new Mock<IApplicationBuilder>();
+            applicationBuilderMock
+                .Setup(s => s.ApplicationServices)
+                .Returns(Mock.Of<IServiceProvider>());
+
+            // Act & Assert
+            var exception = Assert.Throws<InvalidOperationException>(
+                () => applicationBuilderMock.Object.UseMvc(rb => { }));
+
+            Assert.Equal(
+                "Unable to find the required services. Please add all the required services by calling " +
+                "'IServiceCollection.AddMvc' or 'IServiceCollection.AddMvcCore' inside the call to " +
+                "'ConfigureServices(...)' in the application startup code.",
+                exception.Message);
+        }
+    }
+}