templates_have_changed?

# File actionpack/lib/action_view/template/resolver.rb, line 83
      def templates_have_changed?(cached_templates, fresh_templates)
        # if either the old or new template list is empty, we don't need to (and can't)
        # compare modification times, and instead just check whether the lists are different
        if cached_templates.blank? || fresh_templates.blank?
          return fresh_templates.blank? != cached_templates.blank?
        end

        cached_templates_max_updated_at = cached_templates.map(&:updated_at).max

        # if a template has changed, it will be now be newer than all the cached templates
        fresh_templates.any? { |t| t.updated_at > cached_templates_max_updated_at }
      end