version.rb

  def reify_has_manys(model, lookback)
    model.class.reflect_on_all_associations(:has_many).each do |assoc|
      # Get live children.
      children = model.send assoc.name
      # Ensure child models are using PaperTrail.
      if children.first.respond_to? :version_at
        # Handle updated children, and children created since the parent's version.
        children_then = []
        children.each do |child|
          if (child_as_it_was = child.version_at(created_at - lookback.seconds))
            child_as_it_was.attributes.each do |k,v|
              child.send :write_attribute, k.to_sym, v rescue nil
            end
            children_then << child
          end
        end
        children = children_then
        # Now handle children destroyed since the parent's version.
        destroyed_children = Version.all :conditions => [
          "item_type = ? AND event = 'destroy' AND created_at > ?",
          assoc.name.to_s.classify, (created_at - lookback.seconds)]
        #children << destroyed_children.map(&:reify).select{ |child| child.send(foreign_key(model.class.name)) == model.id }
      end
    end
  end