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calling named scope in class method

#263

When a named scope is called inside a class method, it loses the other scopes in the chain. For example:

class Topic < ActiveRecord::Base
  named_scope :approved, :conditions => {:approved => true}
  named_scope :replied, :conditions => ['replies_count > 0']

  def self.approved_through_class_method
    approved
  end
end

Topic.replied.approved_through_class_method # => loses replied scope

What's interesting is that if I append "all" to the approved call in the class method then it will work.

def self.approved_through_class_method
  approved.all
end

Topic.replied.approved_through_class_method # => keeps replied scope

I have attached a failing test, but I'm not familiar enough with named_scope to make it pass.

Reported by Ryan Bates · May 27th, 2008 @ 04:21 PM

Activity

josh
- Assigned user set to Pratik
- Tag set to bug, named_scope, tested
July 17th, 2008 @ 01:59 AM
Pratik
- State changed from new to invalid
This would happen because you're calling approved_through_class_method on Scope object. In case of Topic.replied.approved, Scope#method_missing checks @@scopes hash to see if :approved is a named scope or not. Wherein case of Topic.replied.approved_through_class_method, there is no way to determine if approved_through_class_method is going to return a named scope or not.
The real solution to this would be very fugly and in no way not worth it.
So the practical solution : Define the method in named scope extension.
```
  named_scope :replied, :conditions => ['replies_count > 0'] do
    def approved_through_class_method
      approved
    end
  end
```
July 18th, 2008 @ 03:02 AM