Revert "Fix endpoint routing statefulness."

This reverts commit 9a6881b0e8d2697e5a6a12dd9ddbdfaf6ce6437f.

src/Http/Routing/src/EndpointRoutingMiddleware.cs

@@ -51,8 +51,6 @@ namespace Microsoft.AspNetCore.Routing
             if (endpoint != null)
             {
                 Log.MatchSkipped(_logger, endpoint);
-
-                // Someone else set the endpoint, we'll let them handle the unsetting.
                 return _next(httpContext);
             }
 
@@ -89,7 +87,7 @@ namespace Microsoft.AspNetCore.Routing
         }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        private async Task SetRoutingAndContinue(HttpContext httpContext)
+        private Task SetRoutingAndContinue(HttpContext httpContext)
         {
             // If there was no mutation of the endpoint then log failure
             var endpoint = httpContext.GetEndpoint();
@@ -109,16 +107,7 @@ namespace Microsoft.AspNetCore.Routing
                 Log.MatchSuccess(_logger, endpoint);
             }
 
-            try
-            {
-                await _next(httpContext);
-            }
-            finally
-            {
-                // We unset the endpoint after calling through to the next middleware. This enables any future calls into
-                // endpoint routing don't no-op from there already being an endpoint set.
-                httpContext.SetEndpoint(endpoint: null);
-            }
+            return _next(httpContext);
         }
 
         // Initialization is async to avoid blocking threads while reflection and things

src/Http/Routing/test/UnitTests/EndpointRoutingMiddlewareTest.cs

@@ -21,30 +21,7 @@ namespace Microsoft.AspNetCore.Routing
     public class EndpointRoutingMiddlewareTest
     {
         [Fact]
-        public async Task Invoke_OnException_ResetsEndpoint()
-        {
-            // Arrange
-            var httpContext = CreateHttpContext();
-
-            var middleware = CreateMiddleware(next: context => throw new Exception());
-
-            // Act
-            try
-            {
-                await middleware.Invoke(httpContext);
-            }
-            catch
-            {
-                // Do nothing, we expect the test to throw.
-            }
-
-            // Assert
-            var endpoint = httpContext.GetEndpoint();
-            Assert.Null(endpoint);
-        }
-
-        [Fact]
-        public async Task Invoke_OnCall_SetsEndpointFeatureAndResetsEndpoint()
+        public async Task Invoke_OnCall_SetsEndpointFeature()
         {
             // Arrange
             var httpContext = CreateHttpContext();
@@ -57,16 +34,14 @@ namespace Microsoft.AspNetCore.Routing
             // Assert
             var endpointFeature = httpContext.Features.Get<IEndpointFeature>();
             Assert.NotNull(endpointFeature);
-            Assert.Null(endpointFeature.Endpoint);
         }
 
         [Fact]
-        public async Task Invoke_SkipsRoutingAndMaintainsEndpoint_IfEndpointSet()
+        public async Task Invoke_SkipsRouting_IfEndpointSet()
         {
             // Arrange
             var httpContext = CreateHttpContext();
-            var expectedEndpoint = new Endpoint(c => Task.CompletedTask, new EndpointMetadataCollection(), "myapp");
-            httpContext.SetEndpoint(expectedEndpoint);
+            httpContext.SetEndpoint(new Endpoint(c => Task.CompletedTask, new EndpointMetadataCollection(), "myapp"));
 
             var middleware = CreateMiddleware();
 
@@ -75,7 +50,7 @@ namespace Microsoft.AspNetCore.Routing
 
             // Assert
             var endpoint = httpContext.GetEndpoint();
-            Assert.Same(expectedEndpoint, endpoint);
+            Assert.NotNull(endpoint);
             Assert.Equal("myapp", endpoint.DisplayName);
         }