Adding a scope to ruby gem validation of uniqueness

Question

acts-as-taggable-on gem has a built-in uniqueness validation:

validates_uniqueness_of :name, if: :validates_name_uniqueness?

def validates_name_uniqueness?
  true
end

How do I add a scope to this validation?

I want to add scope: :user_id and don't know how to edit a gem source code.

Answer 1

I was able to fix my problem with the help of acts_as_taggable_on.rb file in config/initializers:

module ActsAsTaggableOn
  class Tag < ::ActiveRecord::Base
    Tag.class_eval do
      _validators.reject!{ |key, _| key == :name }

      _validate_callbacks.each do |callback|
        callback.raw_filter.attributes.delete :name if callback.raw_filter.is_a?(ActiveRecord::Validations::UniquenessValidator)
      end
      validates_uniqueness_of :name, scope: :user_id
    end
  end
end