pass the association and connection to the scope method

activerecord/lib/active_record/associations/association.rb

@@ -94,7 +94,7 @@ def scope
       # actually gets built.
       def association_scope
         if klass
-          @association_scope ||= AssociationScope.new(self).scope
+          @association_scope ||= AssociationScope.new.scope(self, klass.connection)
         end
       end
 

activerecord/lib/active_record/associations/association_scope.rb

 module ActiveRecord
   module Associations
     class AssociationScope #:nodoc:
-      attr_reader :association
-
-      def initialize(association)
-        @association   = association
-      end
-
-      def scope
+      def scope(association, connection)
         klass         = association.klass
         reflection    = association.reflection
         scope         = klass.unscoped
         owner         = association.owner
-        alias_tracker = AliasTracker.new klass.connection
+        alias_tracker = AliasTracker.new connection
 
         scope.extending! Array(reflection.options[:extend])
         add_constraints(scope, owner, klass, reflection, alias_tracker)

activerecord/test/cases/associations/association_scope_test.rb

@@ -6,8 +6,10 @@ module ActiveRecord
   module Associations
     class AssociationScopeTest < ActiveRecord::TestCase
       test 'does not duplicate conditions' do
-        association_scope = AssociationScope.new(Author.new.association(:welcome_posts))
-        wheres = association_scope.scope.where_values.map(&:right)
+        association_scope = AssociationScope.new
+        scope = association_scope.scope(Author.new.association(:welcome_posts),
+                                        Author.connection)
+        wheres = scope.where_values.map(&:right)
         assert_equal wheres.uniq, wheres
       end
     end