Question

What could cause a rails app to have a no method error when using a scope?

I have a basic user class that has cats and dogs. I will need to combine the queries and sort them by created date. Eventually the individual queries will be more complex.

    class User < ActiveRecord::Base
        has_many :dogs
        has_many :cats

       scope :pets, joins(:dogs).joins(:cats).order("created_at desc")

In view

    <%= render @user.pets%>

Is causing an no method error

    undefined method `pets' for #<User:0x00000106370cb0>

Answer 1

Scopes only define class methods on the ActiveRecord model. The proper way to call this would be on the User model directly. User.pets as opposed to an instance of User @user.pets.

What you could do is create a method to be called on a User instance.

   def pets
     User.joins(:dogs).joins(:cats).order("created_at desc")
   end

And thus, @user.pets is allowed.