鐵軌中的錯誤？關於模型繼承

Question

My env: ruby-1.9.2-preview3; rails-3.0.0.beta3 

---

class PostFather < ActiveRecord::Base 
    def self.inherited(subclass) 
    end 
end 

class Post < PostFather 
end 

---

在控制檯：

---

> Post.new # => TypeError: can't dup NilClass 
> Post.all # => TypeError: can't dup NilClass 
> Post.scoped # => TypeError: can't dup NilClass 

---

你可以自己嘗試一下;

Answer 1

ActiveRecord的使用繼承的方法，你需要超級調用，這樣ActiveRecord的東西仍然運行：

class PostFather < ActiveRecord::Base 
    def self.inherited(subclass) 
    super(subclass) 
    end 
end