Multiple Errors on Mutation caused an error to fetch schema

[tessierp]

Product

Hot Chocolate

Version

16

Link to minimal reproduction

I do not have any reproduction URL

Steps to reproduce

Hi,

Not sure if I'm doing something wrong but, following the documentation which specifies that we can handle more than one error on a mutation, I have tried this

[MutationType]
public class ManufacturerMutation
{
    private readonly IManufacturerDal  _manufacturerDal;
    
    public ManufacturerMutation(IManufacturerDal manufacturerDal)
    {
        _manufacturerDal = manufacturerDal;
    }

    [Error(typeof(ManufacturerErrorFactory))]
    public async Task<ManufacturerDto?> AddManufacturer(ManufacturerInput input)
    {
        return await _manufacturerDal.AddManufacturerAsync(input);
    }
}

public static class ManufacturerErrorFactory
{
    public static ManufacturerValidationExceptionError CreateErrorFrom(ValidationException ex)
    {
        return ManufacturerValidationExceptionError.CreateErrorFrom(ex);
    }
    
    public static ManufacturerDbExceptionError CreateErrorFrom(DbException ex)
    {
        return ManufacturerDbExceptionError.CreateErrorFrom(ex);
    }
}

public class ManufacturerDbExceptionError
{
    public DbException Exception { get; }
    public string? Message { get; }
    
    private ManufacturerDbExceptionError(DbException dbEx, string? message = null)
    {
        Exception = dbEx;
        Message = message;
    }
    
    public static ManufacturerDbExceptionError CreateErrorFrom(DbException ex)
    {
        return new ManufacturerDbExceptionError(ex, ex.Message);
    }
}

public class ManufacturerValidationExceptionError
{
    public ValidationException Exception { get; }
    public string? Message { get; }
    
    private ManufacturerValidationExceptionError(ValidationException ex, string? message = null)
    {
        Exception = ex;
        Message = message;
    }

    public static ManufacturerValidationExceptionError CreateErrorFrom(ValidationException ex)
    {
        return new ManufacturerValidationExceptionError(ex, ex.Message);
    }
}

Which gives me the following error

According to the documentation for V16 this should work.. Is there anything I'm missing??

What is expected?

I should be getting a valid schema

What is actually happening?

Schema generation fails and get an error.

Relevant log output

Additional context

No response

[tobias-tengler]

The problem is likely that you're exposing the underlying exception types as public properties on your error types. Hot Chocolate tries to infer those as GraphQL types and fails as seen in your screenshot.
Try to remove those properties or add an [GraphQLIgnore] attribute to them.

[tessierp]

@tobias-tengler Thanks for the suggestion, I'll try that as soon as I can. But I was following the documentation's example

Anyway I'll let you know if that works.

[tessierp]

@tobias-tengler I was too curious and just had to come try this since it was something easy and quick to try. For the Error classes I have set the properties to private but that didn't change a thing. In any case I presume that would be an issue for HotChocolate since, how would it be able to read the data then?

I also tried placing the attribute [GraphQLIgnore] on each of my Error classes properties and same problem occurs.

I also tried just to use use the Exceptions directly on each of my Mutation classes but it complained that I already used it elsewhere so I guess you can't use the same exception twice... but that is another problem for which I may have to open a new case.

Hopefully I can sort these problems out as I would really like to do my project with GraphQL instead of going back to a RESTFul API.

[tobias-tengler]

Could you share the code that you tried without referencing the exception?
Also are you sure the problem is originating from the error types? Could you maybe try to remove the Error attributes on the mutation and see if it works? Maybe there's something wrong with the DTO you're returning as well...

[tessierp]

@tobias-tengler

If I remove the Error attributes, I do not get any issue. As for the DTO they are simple pouco object, there isn't any logic there as it should be for a DTO.

As for the second issue I had using only Exceptions to handle error let me give you more information.

I have two Mutation types, ManufacturerMutation and DeviceMutation, both classes have the [MutationType] attribute. Each class have a ADD mutation to add a manufacturer and device respestively. If on each Add mutation I add the following, [Error(typeof(ValidationException))] I get an error. If I remove this attribute from one of add mutation, everything is fine.

So I thought to myself, OK, this may be normal, it has to be unique but then, that would be an issue because I use FluentValidation in all of my domain models to validate that constraints are respected. Anyway, like I said this I think is a different issue from the one I opened the bug report with.

It could also be that I am not allowed to have multiple classes with the MutationType attribute? I hope not, as I would like to separate things.. I tried this to see if, instead of using the CreateFromError pattern to use the Exception if that would at least be OK but, no joy. Anyway, let me know if you see anything.

[tessierp]

@tobias-tengler Was wondering if you had the time to look into this? Any suggestions?

[tessierp]

Just want to post a quick update. I had version 15.1.8 and upgraded to 15.1.9 and the issues have now been fixed. Not sure if a bug fix was submitted recently but so far so good. Will do a few more tests to make sure.