How to use Entity for describing params when the entity has validations.

[Дмитрий Луцко]

Hi,

Maybe I'm using these tools in the wrong way. But I want to specify a model (Entity) with a set of fields, types, validations and use it for formatting output and for describing inputs. And when I reusing Entity for describing inputs I got an error.

I'm trying to use Grape with Rails 6:

* grape (1.3.0)

* grape-entity (0.7.1)

* grape-swagger (0.33.0)

* grape-swagger-entity (0.3.3)

* grape-swagger-rails (0.3.1)

I use Entity.documentation to specify params:

module Map
  module Locations
    class Create < Grape::API
      resources :locations do
        desc 'Create a location.'


        params do
          requires :all, using: Entities::Loc.documentation
        end


        post do
          locations = ::Location.create!(declared(params))
          present locations, with: Map::Entities::Loc, root: :location
        end
      end
    end
  end
end

When I have a simple entity, it works fine. Here is a simple entity:

module Map
  module Entities
    class Loc < Grape::Entity
      expose :name, documentation: { type: 'String' }
    end
  end
end

But when I add validation

expose :status, documentation: { type: 'String', values: ['new', 'deleted'] }

I'm starting to get error 

Uncaught exception: class or module required

gems/grape-1.3.0/lib/grape/validations/params_scope.rb:435:in `is_a?'

Help me please to find a solution, how to reuse Entity in the right way.