1 files changed, 1 insertions, 4 deletions
diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb
index b13c34d59c..c72024d5f3 100755
--- a/activerecord/lib/active_record/associations.rb
+++ b/activerecord/lib/active_record/associations.rb
@@ -985,7 +985,7 @@ module ActiveRecord
 
           define_method("#{reflection.name}=") do |new_value|
             association = instance_variable_get("@#{reflection.name}")
-            if association.nil?
+            if association.nil? || association.target != new_value
               association = association_proxy_class.new(self, reflection)
             end
 
@@ -995,10 +995,7 @@ module ActiveRecord
               instance_variable_set("@#{reflection.name}", association)
             else
               instance_variable_set("@#{reflection.name}", nil)
-              return nil
             end
-
-            association
           end
 
           define_method("set_#{reflection.name}_target") do |target|