1 files changed, 9 insertions, 4 deletions
diff --git a/activerecord/lib/active_record/nested_attributes.rb b/activerecord/lib/active_record/nested_attributes.rb
index 0c3392263a..f1d3eaed38 100644
--- a/activerecord/lib/active_record/nested_attributes.rb
+++ b/activerecord/lib/active_record/nested_attributes.rb
@@ -2,6 +2,7 @@ require 'active_support/core_ext/hash/except'
 require 'active_support/core_ext/object/try'
 require 'active_support/core_ext/object/blank'
 require 'active_support/core_ext/hash/indifferent_access'
+require 'active_support/core_ext/class/attribute'
 
 module ActiveRecord
   module NestedAttributes #:nodoc:
@@ -11,7 +12,7 @@ module ActiveRecord
     extend ActiveSupport::Concern
 
     included do
-      class_inheritable_accessor :nested_attributes_options, :instance_writer => false
+      class_attribute :nested_attributes_options, :instance_writer => false
       self.nested_attributes_options = {}
     end
 
@@ -268,7 +269,11 @@ module ActiveRecord
           if reflection = reflect_on_association(association_name)
             reflection.options[:autosave] = true
             add_autosave_association_callbacks(reflection)
+
+            nested_attributes_options = self.nested_attributes_options.dup
             nested_attributes_options[association_name.to_sym] = options
+            self.nested_attributes_options = nested_attributes_options
+
             type = (reflection.collection? ? :collection : :one_to_one)
 
             # def pirate_attributes=(attributes)
@@ -315,7 +320,7 @@ module ActiveRecord
     # update_only is true, and a <tt>:_destroy</tt> key set to a truthy value,
     # then the existing record will be marked for destruction.
     def assign_nested_attributes_for_one_to_one_association(association_name, attributes)
-      options = nested_attributes_options[association_name]
+      options = self.nested_attributes_options[association_name]
       attributes = attributes.with_indifferent_access
       check_existing_record = (options[:update_only] || !attributes['id'].blank?)
 
@@ -364,7 +369,7 @@ module ActiveRecord
     #     { :id => '2', :_destroy => true }
     #   ])
     def assign_nested_attributes_for_collection_association(association_name, attributes_collection)
-      options = nested_attributes_options[association_name]
+      options = self.nested_attributes_options[association_name]
 
       unless attributes_collection.is_a?(Hash) || attributes_collection.is_a?(Array)
         raise ArgumentError, "Hash or Array expected, got #{attributes_collection.class.name} (#{attributes_collection.inspect})"
@@ -433,7 +438,7 @@ module ActiveRecord
     end
 
     def call_reject_if(association_name, attributes)
-      case callback = nested_attributes_options[association_name][:reject_if]
+      case callback = self.nested_attributes_options[association_name][:reject_if]
       when Symbol
         method(callback).arity == 0 ? send(callback) : send(callback, attributes)
       when Proc