has_one :through should not create a new association when assigned nil [#698 state:resolved]

Signed-off-by: Pratik Naik <pratiknaik@gmail.com>

activerecord/lib/active_record/associations/has_one_through_association.rb

@@ -1,31 +1,31 @@
 module ActiveRecord
   module Associations
     class HasOneThroughAssociation < HasManyThroughAssociation
-      
+
       def create_through_record(new_value) #nodoc:
         klass = @reflection.through_reflection.klass
 
         current_object = @owner.send(@reflection.through_reflection.name)
-        
+
         if current_object
-          current_object.update_attributes(construct_join_attributes(new_value))
+          new_value ? current_object.update_attributes(construct_join_attributes(new_value)) : current_object.destroy
         else
-          @owner.send(@reflection.through_reflection.name,  klass.send(:create, construct_join_attributes(new_value)))
+          @owner.send(@reflection.through_reflection.name,  klass.send(:create, construct_join_attributes(new_value))) if new_value
         end
       end
-      
+
     private
       def find(*args)
         super(args.merge(:limit => 1))
       end
-    
+
       def find_target
         super.first
       end
 
       def reset_target!
         @target = nil
-      end        
+      end
-    end        
+    end
   end
 end

activerecord/test/cases/associations/has_one_through_associations_test.rb

@@ -43,7 +43,14 @@ class HasOneThroughAssociationsTest < ActiveRecord::TestCase
       @member.reload      
     end
   end
-  
+
+  def test_set_record_to_nil_should_delete_association
+    @member.club = nil
+    @member.reload
+    assert_equal nil, @member.current_membership
+    assert_nil @member.club
+  end
+
   def test_has_one_through_polymorphic
     assert_equal clubs(:moustache_club), @member.sponsor_club
   end