1 files changed, 24 insertions, 1 deletions
diff --git a/activerecord/lib/active_record/reflection.rb b/activerecord/lib/active_record/reflection.rb
index b751c9ad68..d6fad5cf29 100644
--- a/activerecord/lib/active_record/reflection.rb
+++ b/activerecord/lib/active_record/reflection.rb
@@ -252,10 +252,33 @@ module ActiveRecord
         end
       end
 
+      # Returns whether or not this association reflection is for a collection
+      # association. Returns +true+ if the +macro+ is one of +has_many+ or
+      # +has_and_belongs_to_many+, +false+ otherwise.
+      def collection_association?
+        if @collection_association.nil?
+          @collection_association = [:has_many, :has_and_belongs_to_many].include?(macro)
+        end
+        @collection_association
+      end
+
+      # Returns whether or not the association should be validated as part of
+      # the parent's validation.
+      #
+      # Unless you explicitely disable validation with
+      # <tt>:validate => false</tt>, it will take place when:
+      #
+      # * you explicitely enable validation; <tt>:validate => true</tt>
+      # * you use autosave; <tt>:autosave => true</tt>
+      # * the association is a +has_many+ association
+      def validate?
+        !options[:validate].nil? ? options[:validate] : (options[:autosave] == true || macro == :has_many)
+      end
+
       private
         def derive_class_name
           class_name = name.to_s.camelize
-          class_name = class_name.singularize if [ :has_many, :has_and_belongs_to_many ].include?(macro)
+          class_name = class_name.singularize if collection_association?
           class_name
         end