Include exception in ProblemDetailsContext for controller error responses

src/Mvc/Mvc.Core/src/Infrastructure/DefaultProblemDetailsFactory.cs

@@ -4,6 +4,7 @@
 #nullable enable
 
 using System.Diagnostics;
+using Microsoft.AspNetCore.Diagnostics;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc.ModelBinding;
 using Microsoft.Extensions.Options;
@@ -108,6 +109,7 @@ private void ApplyProblemDetailsDefaults(HttpContext httpContext, ProblemDetails
             problemDetails.Extensions["traceId"] = traceId;
         }
 
-        _configure?.Invoke(new() { HttpContext = httpContext!, ProblemDetails = problemDetails });
+        var exception = httpContext?.Features.Get<IExceptionHandlerFeature>()?.Error;
+        _configure?.Invoke(new() { HttpContext = httpContext!, ProblemDetails = problemDetails, Exception = exception });
     }
 }

src/Mvc/Mvc.Core/src/Microsoft.AspNetCore.Mvc.Core.csproj

@@ -53,6 +53,7 @@ Microsoft.AspNetCore.Mvc.RouteAttribute</Description>
     <Reference Include="Microsoft.AspNetCore.Authentication.Core" />
     <Reference Include="Microsoft.AspNetCore.Authorization.Policy" />
     <Reference Include="Microsoft.AspNetCore.Hosting.Abstractions" />
+    <Reference Include="Microsoft.AspNetCore.Diagnostics.Abstractions" />
     <Reference Include="Microsoft.AspNetCore.Http" />
     <Reference Include="Microsoft.AspNetCore.Http.Abstractions" />
     <Reference Include="Microsoft.AspNetCore.Http.Extensions" />

src/Mvc/Mvc.Core/test/Infrastructure/ProblemDetailsFactoryTest.cs

@@ -1,6 +1,9 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+#nullable enable
+
+using Microsoft.AspNetCore.Diagnostics;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc.ModelBinding;
 using Microsoft.Extensions.DependencyInjection;
@@ -169,6 +172,65 @@ public void CreateValidationProblemDetails_WithTitleAndInstance()
            });
     }
 
+    [Fact]
+    public void CreateProblemDetails_IncludesExceptionFromExceptionHandlerFeature()
+    {
+        // Regression test for https://github.com/dotnet/aspnetcore/issues/65697
+        // CustomizeProblemDetails should receive the exception when one is available.
+        Exception? receivedException = null;
+        var expectedException = new InvalidOperationException("BOOM!");
+
+        var options = new ApiBehaviorOptions();
+        new ApiBehaviorOptionsSetup().Configure(options);
+
+        var problemDetailsOptions = new ProblemDetailsOptions
+        {
+            CustomizeProblemDetails = context =>
+            {
+                receivedException = context.Exception;
+            }
+        };
+
+        var factory = new DefaultProblemDetailsFactory(
+            Options.Create(options),
+            Options.Create(problemDetailsOptions));
+
+        var httpContext = GetHttpContext();
+        httpContext.Features.Set<IExceptionHandlerFeature>(
+            new ExceptionHandlerFeature { Error = expectedException });
+
+        factory.CreateProblemDetails(httpContext, statusCode: 500);
+
+        Assert.Same(expectedException, receivedException);
+    }
+
+    [Fact]
+    public void CreateProblemDetails_ExceptionIsNullWhenNoExceptionHandlerFeature()
+    {
+        Exception? receivedException = new Exception("should be overwritten");
+
+        var options = new ApiBehaviorOptions();
+        new ApiBehaviorOptionsSetup().Configure(options);
+
+        var problemDetailsOptions = new ProblemDetailsOptions
+        {
+            CustomizeProblemDetails = context =>
+            {
+                receivedException = context.Exception;
+            }
+        };
+
+        var factory = new DefaultProblemDetailsFactory(
+            Options.Create(options),
+            Options.Create(problemDetailsOptions));
+
+        var httpContext = GetHttpContext();
+
+        factory.CreateProblemDetails(httpContext, statusCode: 400);
+
+        Assert.Null(receivedException);
+    }
+
     private static DefaultHttpContext GetHttpContext()
     {
         return new DefaultHttpContext
@@ -183,4 +245,9 @@ private static ProblemDetailsFactory GetProblemDetails()
         new ApiBehaviorOptionsSetup().Configure(options);
         return new DefaultProblemDetailsFactory(Options.Create(options));
     }
+
+    private sealed class ExceptionHandlerFeature : IExceptionHandlerFeature
+    {
+        public Exception Error { get; init; } = default!;
+    }
 }