The error 'code' is not included in the error response when using AddErrorObjects()

[douggish]

Is there an existing issue for this?

• [X] I have searched the existing issues

Describe the bug

When using Microsoft.AspNetCore.Mvc.Versioning 5.1.0, the error responses contained an error code (e.g. ApiVersionUnspecified). When upgrading to Asp.Versioning 8.1.0, the documentation states that it is possible to retain the previous "Error Object" format (which I would expect to include the code property). However, even when using builder.Services.AddErrorObjects().AddProblemDetails(), there is no code property in the error response.

I'm seeing something like this:

{
    "error": {
        "message": "Unspecified API version",
        "target": "Unspecified API version",
        "innerError": {
            "message": "An API version is required, but was not specified."
        }
    }
}

Expected Behavior

I expected the error response to match what is was in the older version (especially the code property):

{
  "error": {
    "code": "ApiVersionUnspecified",
    "message": "An API version is required, but was not specified.",
    "innerError": null
  }
}

Steps To Reproduce

No response

Exceptions (if any)

No response

.NET Version

8.0.204

Anything else?

I think this line of code is perhaps missing a not: https://github.com/dotnet/aspnet-api-versioning/blob/main/src/AspNetCore/WebApi/src/Asp.Versioning.Http/Routing/EndpointProblem.cs#L28

[commonsensesoftware]

Yeah, it looks like this is meant to be:

+if ( !string.IsNullOrEmpty( code ) )

😳 doh!

[commonsensesoftware]

I'll work on getting out a fix. CRs are also welcome. 😃