# File lib/dm-core/property.rb, line 522
    def set_original_value(resource, original)
      original_attributes = resource.original_attributes
      original            = self.value(original)

      if original_attributes.key?(self)
        # stop tracking the value if it has not changed
        original_attributes.delete(self) if original == original_attributes[self] && resource.saved?
      else
        original_attributes[self] = original
      end
    end