Proposal to expose a class or object of ActiveModel::Errors caller

[Ivan Malykh]

ActiveInteraction and a big amount of other frameworks are using ActiveModel::Errors to implement errors.

When combined with other gems or frameworks that are using ActiveModel it is difficult to find out what class have called `ActiveModel::Errors.new(self)`. For example the following case:

module MyAwesomeFramework
  class Errors < ActiveModel::Errors
    def merge!(other_instance_of_active_model_errors)
      if other_instance_of_active_model_errors.called_by? User # User is an ActiveRecord::Base
        # Use ActiveModel's error translations
      else
        # Do magic to decide what translations to use
      end
    end
  end
end

That is why I propose to expose something like

class ActiveModel::Errors

  #...

  def called_by?(klass)
    caller.class == klass
  end

  def caller
    @base
  end

  #...

end

Not sure about the name of method however.

Thanks in advance, 

Ivan