ruby-on-rails - 单表继承事件管理模型映射问题 rails 4

Question

我创建了一个具有单表继承的多用户这里是我的模型

# user.rb 

class User < ActiveRecord::Base
end

这是用户模型，所有其他模型都是从数据库中的用户继承而来的，它们是一种既存储用户类型又保存用户类型的模型

# customer.rb

class Customer < User
end

# space_owner.rb

class SpaceOwner < User
end

**当我在 active_admin 中映射这些时rails 4 显示了一个错误**

Showing /home/rabnawaz/.rvm/gems/ruby-2.3.1/bundler/gems/activeadmin-0a5a15b88bff/app/views/active_admin/resource/index.html.arb where line #2 raised:

undefined method `chain' for nil:NilClass
Extracted source (around line #709):
  def chain
    @chain ||= begin
      a = source_reflection.chain
      b = through_reflection.chain
      chain = a + b
      chain[0] = self # Use self so we don't lose the information from :source_type

这是我创建时遇到的错误 active_admin显示用户的文件

你能给我一个解决方案吗？

这是我用来创建多个用户的设计路线

devise_for :admin_users, ActiveAdmin::Devise.config
  ActiveAdmin.routes(self)

devise_for :customers, :controllers => { 
    :registrations=>"customers/registrations", 
    :passwords=>"customers/passwords"
  },:skip => :sessions
  devise_for :space_owners, :controllers => { 
    :registrations=>"space_owners/registrations", 
    :passwords=>"space_owners/passwords"
  },:skip => :sessions

Answer 1

给出这个答案引用自 https://github.com/activeadmin/activeadmin/issues/3957 :

After some research I figured out that this error appears when active_record can't automatically infer the name for a nestedassociation. Workaround to handle this could for instance be usingthrough on nested associations.

从您的问题中也不清楚您是否确实向 ActiveAdmin 注册了 User 子类。