Use `ExceptionDispatchInfo` in `MiddlewareFilterBuilder` if available

- #6596
- better-align this code with `ResourceInvoker.Rethrow()`

nits:
- take VS suggestions in `MiddlewareFilterBuilderTest`
- clean up names like `httpCtxt`
- remove unused `Pipeline2` class

src/Microsoft.AspNetCore.Mvc.Core/Internal/MiddlewareFilterBuilder.cs

@@ -71,13 +71,20 @@ namespace Microsoft.AspNetCore.Mvc.Internal
                 var resourceExecutionDelegate = feature.ResourceExecutionDelegate;
 
                 var resourceExecutedContext = await resourceExecutionDelegate();
-
+                if (resourceExecutedContext.ExceptionHandled)
-                // Ideally we want the experience of a middleware pipeline to behave the same as if it was registered,
-                // in Startup. In this scenario an exception thrown in a middelware later in the pipeline gets propagated
-                // back to earlier middleware.
-                // So check if a later resource filter threw an exception and propagate that back to the middleware pipeline.
-                if (!resourceExecutedContext.ExceptionHandled && resourceExecutedContext.Exception != null)
                 {
+                    return;
+                }
+
+                // Ideally we want the experience of a middleware pipeline to behave the same as if it was registered
+                // in Startup. In this scenario, an Exception thrown in a middelware later in the pipeline gets
+                // propagated back to earlier middleware. So, check if a later resource filter threw an Exception and
+                // propagate that back to the middleware pipeline.
+                resourceExecutedContext.ExceptionDispatchInfo?.Throw();
+                if (resourceExecutedContext.Exception != null)
+                {
+                    // This line is rarely reachable because ResourceInvoker captures thrown Exceptions using
+                    // ExceptionDispatchInfo. That said, filters could set only resourceExecutedContext.Exception.
                     throw resourceExecutedContext.Exception;
                 }
             });

test/Microsoft.AspNetCore.Mvc.Core.Test/Internal/MiddlewareFilterBuilderTest.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Runtime.ExceptionServices;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Builder.Internal;
@@ -25,10 +26,13 @@ namespace Microsoft.AspNetCore.Mvc.Internal
             // Arrange
             var services = new ServiceCollection();
             var appBuilder = new ApplicationBuilder(services.BuildServiceProvider());
-            var pipelineBuilderService = new MiddlewareFilterBuilder(new MiddlewareFilterConfigurationProvider());
+            var pipelineBuilderService = new MiddlewareFilterBuilder(new MiddlewareFilterConfigurationProvider())
-            pipelineBuilderService.ApplicationBuilder = appBuilder;
+            {
+                ApplicationBuilder = appBuilder,
+            };
+
             var configureCount = 0;
-            Pipeline1.ConfigurePipeline = (ab) =>
+            Pipeline1.ConfigurePipeline = _ =>
             {
                 configureCount++;
             };
@@ -47,10 +51,13 @@ namespace Microsoft.AspNetCore.Mvc.Internal
             // Arrange
             var services = new ServiceCollection();
             var appBuilder = new ApplicationBuilder(services.BuildServiceProvider());
-            var pipelineBuilderService = new MiddlewareFilterBuilder(new MiddlewareFilterConfigurationProvider());
+            var pipelineBuilderService = new MiddlewareFilterBuilder(new MiddlewareFilterConfigurationProvider())
-            pipelineBuilderService.ApplicationBuilder = appBuilder;
+            {
+                ApplicationBuilder = appBuilder,
+            };
+
             var configureCount = 0;
-            Pipeline1.ConfigurePipeline = (ab) =>
+            Pipeline1.ConfigurePipeline = _ =>
             {
                 configureCount++;
             };
@@ -77,11 +84,15 @@ namespace Microsoft.AspNetCore.Mvc.Internal
             // Arrange
             var services = new ServiceCollection();
             var appBuilder = new ApplicationBuilder(services.BuildServiceProvider());
-            var pipelineBuilderService = new MiddlewareFilterBuilder(new MiddlewareFilterConfigurationProvider());
+            var pipelineBuilderService = new MiddlewareFilterBuilder(new MiddlewareFilterConfigurationProvider())
-            pipelineBuilderService.ApplicationBuilder = appBuilder;
-            Pipeline1.ConfigurePipeline = (ab) =>
             {
-                ab.Use((httpContext, next) =>
+                ApplicationBuilder = appBuilder,
+            };
+
+            var httpContext = new DefaultHttpContext();
+            Pipeline1.ConfigurePipeline = ab =>
+            {
+                ab.Use((_, next) =>
                 {
                     return next();
                 });
@@ -92,36 +103,48 @@ namespace Microsoft.AspNetCore.Mvc.Internal
 
             // Assert
             Assert.NotNull(pipeline);
-            var exception = await Assert.ThrowsAsync<InvalidOperationException>(() => pipeline(new DefaultHttpContext()));
+            var exception = await Assert.ThrowsAsync<InvalidOperationException>(() => pipeline(httpContext));
-            Assert.Equal(
+            Assert.Equal("Could not find 'IMiddlewareFilterFeature' in the feature list.", exception.Message);
-                "Could not find 'IMiddlewareFilterFeature' in the feature list.",
-                exception.Message);
         }
 
         [Fact]
-        public async Task EndMiddleware_PropagatesBackException_ToEarlierMiddleware()
+        public async Task EndMiddleware_DoesNotThrow_IfExceptionHandled()
         {
             // Arrange
             var services = new ServiceCollection();
             var appBuilder = new ApplicationBuilder(services.BuildServiceProvider());
-            var pipelineBuilderService = new MiddlewareFilterBuilder(new MiddlewareFilterConfigurationProvider());
+            var pipelineBuilderService = new MiddlewareFilterBuilder(new MiddlewareFilterConfigurationProvider())
-            pipelineBuilderService.ApplicationBuilder = appBuilder;
-            Pipeline1.ConfigurePipeline = (ab) =>
             {
-                ab.Use((httpCtxt, next) =>
+                ApplicationBuilder = appBuilder,
+            };
+
+            Pipeline1.ConfigurePipeline = ab =>
+            {
+                ab.Use((_, next) =>
                 {
                     return next();
                 });
             };
-            var middlewareFilterFeature = new MiddlewareFilterFeature();
+
-            middlewareFilterFeature.ResourceExecutionDelegate = () =>
+            var middlewareFilterFeature = new MiddlewareFilterFeature
             {
-                var context = new ResourceExecutedContext(
+                ResourceExecutionDelegate = () =>
-                    new ActionContext(new DefaultHttpContext(), new RouteData(), new ActionDescriptor(), new ModelStateDictionary()),
+                {
-                    new List<IFilterMetadata>());
+                    var actionContext = new ActionContext(
-                context.Exception = new InvalidOperationException("Error!!!");
+                        new DefaultHttpContext(),
-                return Task.FromResult(context);
+                        new RouteData(),
+                        new ActionDescriptor(),
+                        new ModelStateDictionary());
+                    var context = new ResourceExecutedContext(actionContext, new List<IFilterMetadata>())
+                    {
+                        Exception = new InvalidOperationException("Error!!!"),
+                        ExceptionHandled = true,
+                    };
+
+                    return Task.FromResult(context);
+                },
             };
+
             var features = new FeatureCollection();
             features.Set<IMiddlewareFilterFeature>(middlewareFilterFeature);
             var httpContext = new DefaultHttpContext(features);
@@ -131,20 +154,148 @@ namespace Microsoft.AspNetCore.Mvc.Internal
 
             // Assert
             Assert.NotNull(pipeline);
-            var exception = await Assert.ThrowsAsync<InvalidOperationException>(() => pipeline(httpContext));
+
-            Assert.Equal("Error!!!", exception.Message);
+            // Does not throw.
+            await pipeline(httpContext);
         }
-        private class Pipeline1
+
+        [Fact]
+        public async Task EndMiddleware_PropagatesBackException_ToEarlierMiddleware()
         {
-            public static Action<IApplicationBuilder> ConfigurePipeline { get; set; }
+            // Arrange
-
+            var services = new ServiceCollection();
-            public void Configure(IApplicationBuilder appBuilder)
+            var appBuilder = new ApplicationBuilder(services.BuildServiceProvider());
+            var pipelineBuilderService = new MiddlewareFilterBuilder(new MiddlewareFilterConfigurationProvider())
             {
-                ConfigurePipeline(appBuilder);
+                ApplicationBuilder = appBuilder,
-            }
+            };
+
+            Pipeline1.ConfigurePipeline = ab =>
+            {
+                ab.Use((_, next) =>
+                {
+                    return next();
+                });
+            };
+
+            var middlewareFilterFeature = new MiddlewareFilterFeature
+            {
+                ResourceExecutionDelegate = () =>
+                {
+                    Exception thrownException;
+                    try
+                    {
+                        // Create a small stack trace.
+                        throw new InvalidOperationException("Error!!!");
+                    }
+                    catch (Exception ex)
+                    {
+                        thrownException = ex;
+                    }
+
+                    var actionContext = new ActionContext(
+                        new DefaultHttpContext(),
+                        new RouteData(),
+                        new ActionDescriptor(),
+                        new ModelStateDictionary());
+                    var context = new ResourceExecutedContext(actionContext, new List<IFilterMetadata>())
+                    {
+                        Exception = thrownException,
+                    };
+
+                    return Task.FromResult(context);
+                },
+            };
+
+            var features = new FeatureCollection();
+            features.Set<IMiddlewareFilterFeature>(middlewareFilterFeature);
+            var httpContext = new DefaultHttpContext(features);
+
+            // Act
+            var pipeline = pipelineBuilderService.GetPipeline(typeof(Pipeline1));
+
+            // Assert
+            Assert.NotNull(pipeline);
+
+            var exception = await Assert.ThrowsAsync<InvalidOperationException>(() => pipeline(httpContext));
+            Assert.Null(exception.InnerException);
+            Assert.Equal("Error!!!", exception.Message);
+
+            var stack = exception.StackTrace;
+            Assert.Contains(typeof(MiddlewareFilterBuilder).FullName, stack);
+            Assert.DoesNotContain(typeof(MiddlewareFilterBuilderTest).FullName, stack);
+            Assert.DoesNotContain(nameof(EndMiddleware_PropagatesBackException_ToEarlierMiddleware), stack);
         }
 
-        private class Pipeline2
+        [Fact]
+        public async Task EndMiddleware_PropagatesFullExceptionInfo_ToEarlierMiddleware()
+        {
+            // Arrange
+            var services = new ServiceCollection();
+            var appBuilder = new ApplicationBuilder(services.BuildServiceProvider());
+            var pipelineBuilderService = new MiddlewareFilterBuilder(new MiddlewareFilterConfigurationProvider())
+            {
+                ApplicationBuilder = appBuilder,
+            };
+
+            Pipeline1.ConfigurePipeline = ab =>
+            {
+                ab.Use((_, next) =>
+                {
+                    return next();
+                });
+            };
+
+            var middlewareFilterFeature = new MiddlewareFilterFeature
+            {
+                ResourceExecutionDelegate = () =>
+                {
+                    ExceptionDispatchInfo exceptionInfo;
+                    try
+                    {
+                        // Create a small stack trace.
+                        throw new InvalidOperationException("Error!!!");
+                    }
+                    catch (Exception ex)
+                    {
+                        exceptionInfo = ExceptionDispatchInfo.Capture(ex);
+                    }
+
+                    var actionContext = new ActionContext(
+                        new DefaultHttpContext(),
+                        new RouteData(),
+                        new ActionDescriptor(),
+                        new ModelStateDictionary());
+                    var context = new ResourceExecutedContext(actionContext, new List<IFilterMetadata>())
+                    {
+                        ExceptionDispatchInfo = exceptionInfo,
+                    };
+
+                    return Task.FromResult(context);
+                },
+            };
+
+            var features = new FeatureCollection();
+            features.Set<IMiddlewareFilterFeature>(middlewareFilterFeature);
+            var httpContext = new DefaultHttpContext(features);
+
+            // Act
+            var pipeline = pipelineBuilderService.GetPipeline(typeof(Pipeline1));
+
+            // Assert
+            Assert.NotNull(pipeline);
+
+            var exception = await Assert.ThrowsAsync<InvalidOperationException>(() => pipeline(httpContext));
+            Assert.Null(exception.InnerException);
+            Assert.Equal("Error!!!", exception.Message);
+
+            var stack = exception.StackTrace;
+            Assert.Contains(typeof(MiddlewareFilterBuilder).FullName, stack);
+            Assert.Contains(typeof(MiddlewareFilterBuilderTest).FullName, stack);
+            Assert.Contains(nameof(EndMiddleware_PropagatesFullExceptionInfo_ToEarlierMiddleware), stack);
+        }
+
+        private class Pipeline1
         {
             public static Action<IApplicationBuilder> ConfigurePipeline { get; set; }