Set StatusCode before disposing HttpContext (#876)

src/Microsoft.AspNetCore.Server.Kestrel/Internal/Http/FrameOfT.cs

@@ -115,21 +115,24 @@ public override async Task RequestProcessingAsync()
                                 await FireOnCompleted();
                             }
 
-                            _application.DisposeContext(context, _applicationException);
-                        }
-
-                        // If _requestAbort is set, the connection has already been closed.
-                        if (Volatile.Read(ref _requestAborted) == 0)
-                        {
-                            ResumeStreams();
-
-                            if (_keepAlive)
+                            // If _requestAbort is set, the connection has already been closed.
+                            if (Volatile.Read(ref _requestAborted) == 0)
                             {
-                                // Finish reading the request body in case the app did not.
-                                await messageBody.Consume();
+                                ResumeStreams();
+
+                                if (_keepAlive)
+                                {
+                                    // Finish reading the request body in case the app did not.
+                                    await messageBody.Consume();
+                                }
+
+                                // ProduceEnd() must be called before _application.DisposeContext(), to ensure
+                                // HttpContext.Response.StatusCode is correct set when
+                                // IHttpContextFactory.Dispose(HttpContext) is called.
+                                await ProduceEnd();
                             }
 
-                            await ProduceEnd();
+                            _application.DisposeContext(context, _applicationException);
                         }
 
                         StopStreams();

test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/ResponseTests.cs

@@ -10,10 +10,14 @@
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Http.Features;
 using Microsoft.AspNetCore.Server.Kestrel.Internal.Http;
 using Microsoft.AspNetCore.Server.Kestrel.Internal.Infrastructure;
 using Microsoft.AspNetCore.Testing;
+using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Internal;
+using Microsoft.Extensions.ObjectPool;
+using Microsoft.Extensions.Options;
 using Microsoft.Extensions.Primitives;
 using Moq;
 using Xunit;
@@ -175,13 +179,50 @@ public async Task OnStartingThrowsWhenSetAfterResponseHasAlreadyStarted()
                 using (var client = new HttpClient())
                 {
                     var response = await client.GetAsync($"http://localhost:{host.GetPort()}/");
-
+                    
                     // Despite the error, the response had already started
                     Assert.Equal(HttpStatusCode.OK, response.StatusCode);
                     Assert.NotNull(ex);
                 }
             }
         }
+
+        [Fact]
+        public async Task ResponseStatusCodeSetBeforeHttpContextDispose()
+        {
+            var mockHttpContextFactory = new Mock<IHttpContextFactory>();
+            mockHttpContextFactory.Setup(f => f.Create(It.IsAny<IFeatureCollection>()))
+                .Returns<IFeatureCollection>(fc => new DefaultHttpContext(fc));
+
+            int disposedStatusCode = -1;
+            mockHttpContextFactory.Setup(f => f.Dispose(It.IsAny<HttpContext>()))
+                .Callback<HttpContext>(c => disposedStatusCode = c.Response.StatusCode);
+
+            var hostBuilder = new WebHostBuilder()
+                .UseKestrel()
+                .UseUrls("http://127.0.0.1:0")
+                .ConfigureServices(services => services.AddSingleton<IHttpContextFactory>(mockHttpContextFactory.Object))
+                .Configure(app =>
+                {
+                    app.Run(context =>
+                    {
+                        throw new Exception();
+                    });
+                });
+
+            using (var host = hostBuilder.Build())
+            {
+                host.Start();
+
+                using (var client = new HttpClient())
+                {
+                    var response = await client.GetAsync($"http://localhost:{host.GetPort()}/");
+                    Assert.Equal(HttpStatusCode.InternalServerError, response.StatusCode);
+                }
+            }
+
+            Assert.Equal(HttpStatusCode.InternalServerError, (HttpStatusCode)disposedStatusCode);
+        }
 
         // https://github.com/aspnet/KestrelHttpServer/pull/1111/files#r80584475 explains the reason for this test.
         [Fact]