2 files changed, 3 insertions, 3 deletions
diff --git a/activerecord/lib/active_record/associations/belongs_to_association.rb b/activerecord/lib/active_record/associations/belongs_to_association.rb
index 681bd1b88d..9dc0e26e10 100644
--- a/activerecord/lib/active_record/associations/belongs_to_association.rb
+++ b/activerecord/lib/active_record/associations/belongs_to_association.rb
@@ -30,7 +30,7 @@ module ActiveRecord
         else
           raise_on_type_mismatch(obj) unless obj.nil?
 
-          @target = obj
+          @target = (AssociationProxy === obj ? obj.target : obj)
           @owner[@association_class_primary_key_name] = obj.id unless obj.new_record?
           @updated = true
         end
diff --git a/activerecord/lib/active_record/associations/has_one_association.rb b/activerecord/lib/active_record/associations/has_one_association.rb
index 1550db69b5..1ff67ff70a 100644
--- a/activerecord/lib/active_record/associations/has_one_association.rb
+++ b/activerecord/lib/active_record/associations/has_one_association.rb
@@ -29,7 +29,7 @@ module ActiveRecord
       def replace(obj, dont_save = false)
         load_target
         unless @target.nil?
-          if dependent? && !dont_save     
+          if dependent? && !dont_save && @target != obj
             @target.destroy unless @target.new_record?
             @owner.clear_association_cache
           else
@@ -44,7 +44,7 @@ module ActiveRecord
           raise_on_type_mismatch(obj)
           
           obj[@association_class_primary_key_name] = @owner.id unless @owner.new_record?
-          @target = obj
+          @target = (AssociationProxy === obj ? obj.target : obj)
         end
 
         @loaded = true