1 files changed, 42 insertions, 7 deletions
diff --git a/activerecord/lib/active_record/associations/has_many_association.rb b/activerecord/lib/active_record/associations/has_many_association.rb
index 2727e23870..d7f655d00c 100644
--- a/activerecord/lib/active_record/associations/has_many_association.rb
+++ b/activerecord/lib/active_record/associations/has_many_association.rb
@@ -6,6 +6,7 @@ module ActiveRecord
     # If the association has a <tt>:through</tt> option further specialization
     # is provided by its child HasManyThroughAssociation.
     class HasManyAssociation < CollectionAssociation #:nodoc:
+      include ForeignAssociation
 
       def handle_dependency
         case options[:dependent]
@@ -41,6 +42,14 @@ module ActiveRecord
         end
       end
 
+      def empty?
+        if has_cached_counter?
+          size.zero?
+        else
+          super
+        end
+      end
+
       private
 
         # Returns the number of records in this collection.
@@ -58,7 +67,7 @@ module ActiveRecord
         # the loaded flag is set to true as well.
         def count_records
           count = if has_cached_counter?
-            owner.read_attribute cached_counter_attribute_name
+            owner._read_attribute cached_counter_attribute_name
           else
             scope.count
           end
@@ -80,11 +89,22 @@ module ActiveRecord
         end
 
         def update_counter(difference, reflection = reflection())
+          update_counter_in_database(difference, reflection)
+          update_counter_in_memory(difference, reflection)
+        end
+
+        def update_counter_in_database(difference, reflection = reflection())
           if has_cached_counter?(reflection)
             counter = cached_counter_attribute_name(reflection)
             owner.class.update_counters(owner.id, counter => difference)
+          end
+        end
+
+        def update_counter_in_memory(difference, reflection = reflection())
+          if has_cached_counter?(reflection)
+            counter = cached_counter_attribute_name(reflection)
             owner[counter] += difference
-            owner.changed_attributes.delete(counter) # eww
+            owner.send(:clear_attribute_changes, counter) # eww
           end
         end
 
@@ -100,8 +120,12 @@ module ActiveRecord
         # Hence this method.
         def inverse_updates_counter_cache?(reflection = reflection())
           counter_name = cached_counter_attribute_name(reflection)
+          inverse_updates_counter_named?(counter_name, reflection)
+        end
+
+        def inverse_updates_counter_named?(counter_name, reflection = reflection())
           reflection.klass._reflections.values.any? { |inverse_reflection|
-            :belongs_to == inverse_reflection.macro &&
+            inverse_reflection.belongs_to? &&
             inverse_reflection.counter_cache_column == counter_name
           }
         end
@@ -130,12 +154,23 @@ module ActiveRecord
           end
         end
 
-        def foreign_key_present?
-          if reflection.klass.primary_key
-            owner.attribute_present?(reflection.association_primary_key)
+        def concat_records(records, *)
+          update_counter_if_success(super, records.length)
+        end
+
+        def _create_record(attributes, *)
+          if attributes.is_a?(Array)
+            super
           else
-            false
+            update_counter_if_success(super, 1)
+          end
+        end
+
+        def update_counter_if_success(saved_successfully, difference)
+          if saved_successfully
+            update_counter_in_memory(difference)
           end
+          saved_successfully
         end
     end
   end