NoMethodError: private method `existence_check' called for Class

Question

我有一个很奇怪的问题。

场景：我正在 Rails 中与 MongoDB 一起制作照片集（mongoid gem )，其中每张照片都属于一个相册。一些 mongo 字段由关注点提供，并且模型已正确命名。所以，

担忧：MediaConcerns::Base

module MediaConcerns
  module Base
    extend ActiveSupport::Concern

    included do
      field :photo_description, type: String
    end
  end
end

担忧：MediaCollectionConcerns::Base

module MediaCollectionConcerns
  module Base
    extend ActiveSupport::Concern

    included do
      field :album_title, type: String
      field :album_description, type: String
    end
  end
end

而MediaType::Photo是：

module MediaType
  class Photo
    include Mongoid::Document
    include Mongoid::Timestamps::Short
    include MediaConcerns::Base

    embedded_in :photo_album, class_name: 'MediaCollection::PhotoAlbum'    
  end
end

而 MediaCollection::PhotoAlbum 是：

module MediaCollection
  class PhotoAlbum
    include Mongoid::Document
    include Mongoid::Timestamps::Short
    include MediaCollectionConcerns::Base

    embeds_many :photos, class_name: 'MediaType::Photo'
  end
end

顾虑与否，问题依旧，与embedded_in和embeds_many有关。

通过 Rails 控制台，当我尝试 MediaCollection::PhotoAlbum.new 它给出：

NoMethodError: private method `existence_check' called for MediaCollection::PhotoAlbum:Class
from /home/marco/.rvm/gems/ruby-2.4.0/gems/mongoid-6.1.0/lib/mongoid/relations/macros.rb:355:in `relate'
from /home/marco/.rvm/gems/ruby-2.4.0/gems/mongoid-6.1.0/lib/mongoid/relations/macros.rb:85:in `embeds_many'
from /home/marco/workspace/backend/app/models/media_collection/photo_album.rb:10:in `<class:PhotoAlbum>'
from /home/marco/workspace/backend/app/models/media_collection/photo_album.rb:2:in `<module:MediaCollection>'
from /home/marco/workspace/backend/app/models/media_collection/photo_album.rb:1:in `<top (required)>'

MediaType::Photo.new也一样：

NoMethodError: private method `existence_check' called for MediaType::Photo:Class
from /home/marco/.rvm/gems/ruby-2.4.0/gems/mongoid-6.1.0/lib/mongoid/relations/macros.rb:355:in `relate'
from /home/marco/.rvm/gems/ruby-2.4.0/gems/mongoid-6.1.0/lib/mongoid/relations/macros.rb:56:in `embedded_in'
from /home/marco/workspace/backend/app/models/media_type/photo.rb:15:in `<class:Photo>'
from /home/marco/workspace/backend/app/models/media_type/photo.rb:2:in `<module:MediaType>'
from /home/marco/workspace/backend/app/models/media_type/photo.rb:1:in `<top (required)>'

有什么问题吗？如果我删除（仅用于调试）关系 embeds_many 和 embedded_in，问题就解决了，但我需要嵌入这些文档！

也许 Rails 找不到 :photos，但我已按照 mongoid 文档的建议指定了 class_name: 'MediaType::Photo'，并且为 [= 指定了相同的内容28=]

我需要帮助。谢谢。

Answer 1

我终于找到了原因但没有解决，是gem上的一个bug。

阅读此处：github issue

NoMethodError: private method `existence_check' called for Class

NoMethodError: private method `existence_check' called for Class

ruby-on-rails

ruby

mongodb

mongoid