[BUG] ValidationApiException.Content deserialization (ProblemDetails) bypasses IHttpContentSerializer

[hakenr]

Describe the bug
ValidationApiException.Content deserialization (ProblemDetails) is now hardcoded in ValidationApiException.Create() and uses the System.Text.Json.JsonSerializer.Deserialize<ProblemDetails>() no matter whether there is any IHttpContentSerializer set.

public static ValidationApiException Create(ApiException exception)
{
    if (exception is null)
        throw new ArgumentNullException(nameof(exception));
    if (string.IsNullOrWhiteSpace(exception.Content))
        throw new ArgumentException("Content must be an 'application/problem+json' compliant json string.");

    var ex = new ValidationApiException(exception);

    if(!string.IsNullOrWhiteSpace(exception.Content))
    {
        ex.Content = JsonSerializer.Deserialize<ProblemDetails>(exception.Content!, SerializerOptions);
    }

    return ex;
}

The original implementation used to use IHttpContentSerializer for ProblemDetails deserialization. We use the IHttpContentSerializer for some custom-transformations of the incoming ProblemDetails, which is no longer possible.

public static async Task<ValidationApiException> Create(ApiException exception)
{
    return new ValidationApiException(exception)
    {
        Content = await exception.GetContentAsAsync<ProblemDetails>().ConfigureAwait(false)
    };
}

Expected behavior
ValidationApiException.Content being deserialized using the configured IHttpContentSerializer.

Workaround
You can call validationException.GetContentAsAsync<ProblemDetails>() on your own. It uses the IHttpContentSerializer and can help you get the result you need.

[angularsen]

We just hit this too, I expected Newtonsoft to be used to deserialize problem details extensions when Newtonsoft was configured, but we got System.Text.Json.JsonElement types instead for the objects in the Dictionary<string, object> Extensions property.

It is fine once you know about it, but it is a pitfall and we now have to have code in place to handle both Newtonsoft and SystemJson in case Refit changes this behavior in the future.