- Synchronize timestamps when touching embedded documents

- Do not run :touch in after_touch callback on embedded, since it's fully handled within the :touch method itself

Author: johnnyshields

lib/mongoid/touchable.rb

@@ -42,10 +42,14 @@ def touch(field = nil)
       # @api private
       def __gather_touch_updates(now, field = nil)
         field = database_field_name(field)
+        # TODO: we should check the type of field is time-like (date/time/datetime/bson-timestamp) before writing
         write_attribute(:updated_at, now) if respond_to?("updated_at=")
         write_attribute(field, now) if field
 
         touches = __extract_touches_from_atomic_sets(field) || {}
+
+        # TODO: this needs to a guard `... if _parent && _association_to_parent.options[:touch]`
+        # However, the `_association_to_parent` method doesn't exist!
         touches.merge!(_parent.__gather_touch_updates(now) || {}) if _parent
         touches
       end
@@ -78,6 +82,7 @@ def __extract_touches_from_atomic_sets(field = nil)
         updates = atomic_updates['$set']
         return {} unless updates
 
+        # TODO: this should evaluate the field alias of updated_at rather than assuming u_at
         touchable_keys = %w(updated_at u_at)
         touchable_keys << field.to_s if field.present?
 
@@ -104,9 +109,13 @@ def define_touchable!(association)
       name = association.name
       method_name = define_relation_touch_method(name, association)
       association.inverse_class.tap do |klass|
+        # TODO: for EMBEDDED docs, save/destroy we should call .touch within the save/destroy
+        # action rather than as a callback this will ensure synchronized timestamps
         klass.after_save method_name
         klass.after_destroy method_name
-        klass.after_touch method_name
+
+        # Embedded docs recursively handle touch updates within the #touch method itself
+        klass.after_touch method_name unless association.embedded?
       end
     end