Ruby on rails 如何针对pg_搜索中具有`as:`名称的关联指定`associated_`？

好的，我有一个

节点

模型，它有以下关联：

class Node < ActiveRecord::Base
  belongs_to :family_tree
  belongs_to :user
  belongs_to :media, polymorphic: true, dependent: :destroy
  has_many :comments, dependent: :destroy
end

但是我不太明白如何在我的

pg\u搜索范围
中指定这一点

我试过这个：

  include PgSearch
  pg_search_scope :node_search, against: [:name, :user_id, :circa, :cached_user_tag_list, :cached_tagged_user_names],
    using: { tsearch: { any_word: true, dictionary: :english, prefix: true} },
    :associated_against => {
      video: [:description, :title]
    }

但我得到的错误是：

Completed 500 Internal Server Error in 131ms (ActiveRecord: 41.6ms)    
NoMethodError - undefined method `table_name' for nil:NilClass:

因此，当我尝试这种方式时：

  include PgSearch
  pg_search_scope :node_search, against: [:name, :user_id, :circa, :cached_user_tag_list, :cached_tagged_user_names],
    using: { tsearch: { any_word: true, dictionary: :english, prefix: true} },
    :associated_against => {
      media: [:description, :title]
    }

我得到这个错误：

Completed 500 Internal Server Error in 126ms (ActiveRecord: 17.7ms)    
NameError - uninitialized constant Node::Media:

我如何指定该关联，或者这是pg_搜索不知道如何管理的边缘？
pg_搜索的维护者提到，多态关联无法通过SQL直接搜索，因此无法用于pg_搜索-

Completed 500 Internal Server Error in 126ms (ActiveRecord: 17.7ms)    
NameError - uninitialized constant Node::Media: