unscopedなassociationなやつ

active_record.rb

# config/initializers/active_record.rb
class ActiveRecord::Base
  class << self

    # 参考: http://techracho.bpsinc.jp/baba/2011_11_28/4729

    def define_unscoped_model(name, model, options = {})
      model_name = if options[:class_name]
        options[:class_name].to_s
      else
        (options[:source] || model).to_s.classify
      end
      define_method "unscoped_#{model}" do
        model_name.constantize.unscoped do
          relation = __send__(model)
          if name == 'belongs_to'
            relation
          else
            relation.order
          end
        end
      end
    end
    private :define_unscoped_model

    %w(belongs_to has_many has_and_belongs_to_many).each do |name|
      new_method = "#{name}_with_unscoped"
      old_method = "#{name}_without_unscoped"
      define_method new_method do |model, options = {}|
        __send__(old_method, model, options)
        define_unscoped_model(name, model, options) unless options[:polymorphic] #とりあえずpolymorphic無視
      end
      alias_method_chain name, :unscoped unless method_defined? old_method
    end

  end
end