removed :piggyback in favor of just allowing :select on :through associations

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@3326 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/CHANGELOG

 *SVN*
 
+* removed :piggyback in favor of just allowing :select on :through associations. [Tobias Luetke]
+
 * made method missing delegation to class methods on relation target work on :through associations. [Tobias Luetke]
 
 * made .find() work on :through relations. [Tobias Luetke]

activerecord/lib/active_record/associations.rb

@@ -881,7 +881,7 @@ def create_has_many_reflection(association_id, options, &extension)
             :class_name, :table_name, :foreign_key,
             :exclusively_dependent, :dependent,
             :select, :conditions, :include, :order, :group, :limit, :offset,
-            :as, :through, :piggyback, 
+            :as, :through, 
             :finder_sql, :counter_sql, 
             :before_add, :after_add, :before_remove, :after_remove, 
             :extend

activerecord/lib/active_record/associations/has_many_through_association.rb

@@ -85,11 +85,7 @@ def construct_from
         end
         
         def construct_select
-          selected = ["#{@reflection.table_name}.*"]          
-          if @reflection.options[:piggyback]
-            selected += [@reflection.options[:piggyback]].flatten.collect { |field| "#{@owner.class.reflections[@reflection.options[:through]].table_name}.#{field}" } 
-          end
-          selected.join(', ')
+          selected = @reflection.options[:select] || "#{@reflection.table_name}.*"          
         end
         
         def construct_scope

activerecord/test/fixtures/category.rb

@@ -6,7 +6,7 @@ def self.what_are_you
   end
   
   has_many :categorizations
-  has_many :authors, :through => :categorizations, :piggyback => [:post_id]  
+  has_many :authors, :through => :categorizations, :select => 'authors.*, categorizations.post_id'
 end
 
 class SpecialCategory < Category