DefaultApiProblemDetailsWriter.WriteAsync loses original context.ProblemDetails.Exception value

[wasker]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

I'm trying to add raw exception into problem response in CustomizeProblemDetails in dev environment, however, context.Exception is always null.

Expected Behavior

Exception should not be null.

Steps To Reproduce

builder.Services
    .AddProblemDetails()
    .AddExceptionHandler(options =>
    {
        options.StatusCodeSelector = exception => exception switch
        {
            FailedToAuthenticateTokenException _ => StatusCodes.Status401Unauthorized,
            _ => (int) HttpStatusCode.InternalServerError
        };
    });

builder.Services.Configure<ProblemDetailsOptions>(options =>
{
    var dumpException = builder.Environment.IsDevelopment();

    options.CustomizeProblemDetails = context =>
    {
        var exception = context.Exception;
        if (exception is not null)
        {
            if (dumpException)
            {
                context.ProblemDetails.Extensions["exception"] = exception.ToString();
            }
        }
    };
});

var app = builder.Build();

app.UseExceptionHandler();

Exceptions (if any)

No response

.NET Version

9.0.305

Anything else?

Exception handler actually adds exception to problem details. However, DefaultApiProblemDetailsWriter then re-creates problem details and ignores exception which was in original data.

[wu-yafeng]

This is documented behavior, you should call AddProblemDetails before AddControllers

see https://learn.microsoft.com/en-us/aspnet/core/fundamentals/error-handling?view=aspnetcore-10.0#custom-iproblemdetailswriter

Note: When using a custom IProblemDetailsWriter, the custom IProblemDetailsWriter must be registered before calling AddRazorPages, AddControllers, AddControllersWithViews, or AddMvc:

[wasker]

@wu-yafeng Thanks, but I'm using CustomizeProblemDetails, not a custom problem writer.

https://learn.microsoft.com/en-us/aspnet/core/fundamentals/error-handling?view=aspnetcore-10.0#customizeproblemdetails-operation

[wu-yafeng]

@wu-yafeng Thanks, but I'm using CustomizeProblemDetails, not a custom problem writer.

https://learn.microsoft.com/en-us/aspnet/core/fundamentals/error-handling?view=aspnetcore-10.0#customizeproblemdetails-operation

When you call AddProblemDetails() , this method will try register a DefaultProblemWriter.
When you call AddController(), this method will try register a DefaultApiProblemWriter.

see

aspnetcore/src/Http/Http.Extensions/src/DefaultProblemDetailsWriter.cs

Line 55 in ecf3c2d

var httpContext = context.HttpContext;

[wasker]

Thanks, moving AddProblemDetails before AddControllers addressed the issue.