IModelValidatorFactory is registered twice into DI container when using FluentValidation

[ghost]

NancyBootstrapperBase registers two IModelValidatorFactory instances when Nancy.Validation.FluentValidation NuGet package is being used. Having two factories causes the validation errors to appear twice.

Original description of this issue with code examples available here:
https://gist.github.com/mattilaj/24732c8353065f9bcfc5

A minimal reproducible is available for download here:
https://skydrive.live.com/redir?resid=D6C0FB440C48EDBB!530&authkey=!AKy9iTzYKff25DE

[xt0rted]

I'm seeing this issue as well but I'm using Data Annotations Validation and StructureMap. When I switch back to TinyIoC I don't have the problem.

Either of these overrides in my bootstrapper seems to fix the problem.

protected override IEnumerable<IApplicationRegistrations> GetApplicationRegistrationTasks()
{
    return ApplicationContainer.GetAllInstances<IApplicationRegistrations>()
                                .Where(t => t.GetType() != typeof (Nancy.Validation.DataAnnotations.ApplicationRegistrations));
}

protected override void RegisterTypes(IContainer container, IEnumerable<TypeRegistration> typeRegistrations)
{
    container.Configure(registry =>
    {
        foreach (var typeRegistration in typeRegistrations)
        {
            if (typeRegistration.ImplementationType == typeof (DataAnnotationsValidator) ||
                typeRegistration.ImplementationType == typeof (DataAnnotationsValidatorFactory))
            {
                continue;
            }

            registry.For(typeRegistration.RegistrationType)
                    .LifecycleIs(InstanceScope.Singleton)
                    .Use(typeRegistration.ImplementationType);
        }
    });
}

[grumpydev]

@thecodejunkie is this fixed by #1267 ?

[maniserowicz]

This behavior is still here in v0.21.1.0, I'm using Autofac and Fluent. Needed to write a similar workaround:

protected override void RegisterTypes(ILifetimeScope container, IEnumerable<TypeRegistration> typeRegistrations)
{
    base.RegisterTypes(container, typeRegistrations.Where(
        // this factory is registered as TypeRegistration and CollectionTypeRegistration for some reason
        // which results in validators being used twice each time, generating two error messages
        // ignoring this component here solves the problem
        x => x.ImplementationType != typeof(FluentValidationValidatorFactory))
    );
}

[thecodejunkie]

It's being fixed for 0.22, as part of the Model Validation Overhaul #1265 and more specifically by #1267 which has been pulled into master