Added destruction of dependent objects in has_one associations when a new assignment happens #742 [mindel]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@843 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

3 files changed, 13 insertions, 3 deletions

diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb
index 381f3e4931..229cfb5cfa 100755
--- a/activerecord/lib/active_record/associations.rb
+++ b/activerecord/lib/active_record/associations.rb
@@ -270,7 +270,8 @@ module ActiveRecord
       #   sql fragment, such as "rank = 5".
       # * <tt>:order</tt>       - specify the order from which the associated object will be picked at the top. Specified as
       #    an "ORDER BY" sql fragment, such as "last_name, first_name DESC"
-      # * <tt>:dependent</tt>   - if set to true the associated object is destroyed alongside this object
+      # * <tt>:dependent</tt>   - if set to true, the associated object is destroyed when this object is. It's also destroyed if another
+      #   association is assigned.
       # * <tt>:foreign_key</tt> - specify the foreign key used for the association. By default this is guessed to be the name
       #   of this class in lower-case and "_id" suffixed. So a +Person+ class that makes a has_one association will use "person_id"
       #   as the default foreign_key.
diff --git a/activerecord/lib/active_record/associations/association_proxy.rb b/activerecord/lib/active_record/associations/association_proxy.rb
index 009e2ec4c2..91da7dec4d 100644
--- a/activerecord/lib/active_record/associations/association_proxy.rb
+++ b/activerecord/lib/active_record/associations/association_proxy.rb
@@ -34,6 +34,10 @@ module ActiveRecord
       end
 
       protected
+        def dependent?
+          @options[:dependent] || false
+        end
+        
         def quoted_record_ids(records)
           records.map { |record| record.quoted_id }.join(',')
         end
diff --git a/activerecord/lib/active_record/associations/has_one_association.rb b/activerecord/lib/active_record/associations/has_one_association.rb
index 30704b6f7e..e566089013 100644
--- a/activerecord/lib/active_record/associations/has_one_association.rb
+++ b/activerecord/lib/active_record/associations/has_one_association.rb
@@ -10,8 +10,13 @@ module ActiveRecord
       def replace(obj, dont_save = false)
         load_target
         unless @target.nil?
-          @target[@association_class_primary_key_name] = nil
-          @target.save unless @owner.new_record?
+          if dependent? && !dont_save     
+            @target.destroy unless @target.new_record?
+            @owner.clear_association_cache
+          else
+            @target[@association_class_primary_key_name] = nil
+            @target.save unless @owner.new_record?
+          end
         end
 
         if obj.nil?