Handle sync exceptions within async context

Author: ryanbrandenburg

src/Mvc/Mvc.ViewFeatures/src/ViewExecutor.cs

@@ -233,7 +233,7 @@ protected async Task ExecuteAsync(
 
             OnExecuting(viewContext);
 
-            using (var writer = WriterFactory.CreateWriter(response.Body, resolvedContentTypeEncoding))
+            await using (var writer = WriterFactory.CreateWriter(response.Body, resolvedContentTypeEncoding))
             {
                 var view = viewContext.View;
 

src/Mvc/test/Mvc.FunctionalTests/TagHelpersTest.cs

@@ -64,6 +64,16 @@ public async Task CanRenderViewsWithTagHelpers(string action)
 #endif
         }
 
+        [Fact]
+        public async Task GivesCorrectCallstackForSyncronousCalls()
+        {
+            // Arrange, Act and Assert
+            var exception = await Assert.ThrowsAsync<HttpRequestException>(async () => await Client.GetAsync("http://localhost/Home/MyHtml"));
+
+            // Assert
+            Assert.Equal("Should be visible", exception.InnerException.InnerException.Message);
+        }
+
         [Fact]
         public async Task CanRenderViewsWithTagHelpersAndUnboundDynamicAttributes_Encoded()
         {

src/Mvc/test/WebSites/TagHelpersWebSite/Controllers/HomeController.cs

@@ -35,6 +35,11 @@ public IActionResult Help()
             return View();
         }
 
+        public IActionResult MyHtml()
+        {
+            return View();
+        }
+
         public IActionResult ViewComponentTagHelpers()
         {
             return View();

src/Mvc/test/WebSites/TagHelpersWebSite/MyHtmlContent.cs

@@ -0,0 +1,27 @@
+// 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 System.IO;
+using System.Text.Encodings.Web;
+using Microsoft.AspNetCore.Html;
+using Microsoft.AspNetCore.Mvc.Rendering;
+
+namespace TagHelpersWebSite
+{
+    public class MyHtmlContent : IHtmlContent
+    {
+        private IHtmlHelper Html { get; }
+
+        public MyHtmlContent(IHtmlHelper html)
+        {
+            Html = html;
+        }
+
+        public void WriteTo(TextWriter writer, HtmlEncoder encoder)
+        {
+#pragma warning disable MVC1000 // Use of IHtmlHelper.{0} should be avoided.
+            Html.Partial("_Test").WriteTo(writer, encoder);
+#pragma warning restore MVC1000 // Use of IHtmlHelper.{0} should be avoided.
+        }
+    }
+}

src/Mvc/test/WebSites/TagHelpersWebSite/Startup.cs

@@ -3,6 +3,7 @@
 
 using System.IO;
 using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Diagnostics;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.Extensions.DependencyInjection;
@@ -20,6 +21,7 @@ public void ConfigureServices(IServiceCollection services)
 
         public void Configure(IApplicationBuilder app)
         {
+            app.UseDeveloperExceptionPage();
             app.UseRouting();
             app.UseStaticFiles();
             app.UseEndpoints(endpoints =>

src/Mvc/test/WebSites/TagHelpersWebSite/TagHelpersWebSite.csproj

@@ -12,8 +12,11 @@
 
   <ItemGroup>
     <Reference Include="Microsoft.AspNetCore.Mvc" />
+    <Reference Include="Microsoft.AspNetCore.Diagnostics" />
     <Reference Include="Microsoft.AspNetCore.Server.IISIntegration" />
     <Reference Include="Microsoft.AspNetCore.Server.Kestrel" />
     <Reference Include="Microsoft.AspNetCore.StaticFiles" />
+    <Reference Include="Microsoft.Extensions.Logging.Console" />
+    <Reference Include="Microsoft.Extensions.Logging.Debug" />
   </ItemGroup>
 </Project>

src/Mvc/test/WebSites/TagHelpersWebSite/Views/Home/MyHtml.cshtml

@@ -0,0 +1 @@
+@(new TagHelpersWebSite.MyHtmlContent(Html))

src/Mvc/test/WebSites/TagHelpersWebSite/Views/Home/_Test.cshtml

@@ -0,0 +1,3 @@
+@{
+    throw new Exception("Should be visible");
+}