Allow association redefinition in subclasses. Closes #9346.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@8046 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

1 files changed, 4 insertions, 2 deletions

diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb
index e542e8d85a..654b24d71c 100755
--- a/activerecord/lib/active_record/associations.rb
+++ b/activerecord/lib/active_record/associations.rb
@@ -955,7 +955,7 @@ module ActiveRecord
         # Don't use a before_destroy callback since users' before_destroy
         # callbacks will be executed after the association is wiped out.
         old_method = "destroy_without_habtm_shim_for_#{reflection.name}"
-        class_eval <<-end_eval
+        class_eval <<-end_eval unless method_defined?(old_method)
           alias_method :#{old_method}, :destroy_without_callbacks
           def destroy_without_callbacks
             #{reflection.name}.clear
@@ -1351,7 +1351,9 @@ module ActiveRecord
             defined_callbacks = options[callback_name.to_sym]
             if options.has_key?(callback_name.to_sym)
               class_inheritable_reader full_callback_name.to_sym
-              write_inheritable_array(full_callback_name.to_sym, [defined_callbacks].flatten)
+              write_inheritable_attribute(full_callback_name.to_sym, [defined_callbacks].flatten)
+            else
+              write_inheritable_attribute(full_callback_name.to_sym, [])
             end
           end
         end