Question

Following Problem:
I need something like an empty scope. Which means that this scope is emtpy, but responds to all methods a scope usually responds to.
I’m currently using a little dirty hack. I simply supply “1=0” as conditions. I find this realy ugly, since it hits the database. Simply returning an empty array won’t work, since the result must respond to the scoped methods.

Is there a better existing solution for this or will I need to code this myself?

Maybe some example code could help explain what i need:

class User < ActiveRecord::Base
  named_scope :admins, :conditions => {:admin => true }
  named_scope :none_dirty, :conditions => "1=0" # this scope is always empty

  def none_broken
    []
  end

  def self.sum_score # okay, a bit simple, but a method like this should work!
    total = 0
    self.all.each do |user|
      total += user.score
    end
    return total
  end
end
User.admin.sum_score # the score i want to know
User.none_drity.sum_score # works, but hits the db
User.none_broken.sum_score # ...error, since it doesn't respond to sum_score

Answer 1

The thing you are looking for does not exist. You could implement something like this by monky patching the find method. Yet, this would be an overkill, so I recomend keeping this unless it’s performance critical.