Question

我正在使用Rails 4/5中的嵌套表单。在Rails4中使用@my_model_instance.build的代码似乎在Rails 5中不起作用。我不确定这是一个错误还是我的错

详细信息：

Rails 4.2.3控制台：

> @item = ItemType.new
=> #<ItemType id: nil, name: nil, .... >
> @item.item_abilities
=> #<ActiveRecord::Associations::CollectionProxy []>
> @item.item_abilities.build
=> #<ItemAbility id: nil, item_type_id: nil, ... >
> @item.item_abilities
=> #<ActiveRecord::Associations::CollectionProxy [#<ItemAbility id: nil, item_type_id: nil, ... ]>

这符合记录/预期。现在让我们在Rails 5（rc2）中的相同代码库上尝试相同的东西。

Rails 5.0.0rc2 console：

> @item = ItemType.new
=> #<ItemType id: nil, name: nil, .... >
> @item.item_abilities
=> #<ActiveRecord::Associations::CollectionProxy []>
> @item.item_abilities.build
ArgumentError: wrong number of arguments (given 2, expected 0..1)
from /var/lib/gems/2.3.0/gems/activerecord-5.0.0.rc2/lib/active_record/core.rb:312:in `initialize'
from /var/lib/gems/2.3.0/gems/activerecord-5.0.0.rc2/lib/active_record/inheritance.rb:65:in `new'
from /var/lib/gems/2.3.0/gems/activerecord-5.0.0.rc2/lib/active_record/inheritance.rb:65:in `new'
from /var/lib/gems/2.3.0/gems/protected_attributes-1.1.3/lib/active_record/mass_assignment_security/reflection.rb:8:in `build_association'
from /var/lib/gems/2.3.0/gems/protected_attributes-1.1.3/lib/active_record/mass_assignment_security/associations.rb:7:in `build_record'
from /var/lib/gems/2.3.0/gems/protected_attributes-1.1.3/lib/active_record/mass_assignment_security/associations.rb:25:in `build'
from /var/lib/gems/2.3.0/gems/protected_attributes-1.1.3/lib/active_record/mass_assignment_security/associations.rb:64:in `build'
from (irb):2
from /var/lib/gems/2.3.0/gems/railties-5.0.0.rc2/lib/rails/commands/console.rb:65:in `start'
from /var/lib/gems/2.3.0/gems/railties-5.0.0.rc2/lib/rails/commands/console_helper.rb:9:in `start'
from /var/lib/gems/2.3.0/gems/railties-5.0.0.rc2/lib/rails/commands/commands_tasks.rb:78:in `console'
from /var/lib/gems/2.3.0/gems/railties-5.0.0.rc2/lib/rails/commands/commands_tasks.rb:49:in `run_command!'
from /var/lib/gems/2.3.0/gems/railties-5.0.0.rc2/lib/rails/commands.rb:18:in `<top (required)>'
from bin/rails:4:in `require'
from bin/rails:4:in `<main>'

这是我正在做的事情，还是Rails5疯了？

模型的相关部分：

item_type.rb

class ItemType < ActiveRecord::Base
    ## Relationships
    belongs_to :item_collection
    has_many :item_abilities
    has_many :item_instances

    accepts_nested_attributes_for :item_abilities

    ...
end

item_instance.rb

class ItemAbility < ActiveRecord::Base
    # Relationships
    belongs_to :item_type
   ...
end

Ruby版本：

ruby 2.3.1p112 (2016-04-26) [x86_64-linux-gnu]

Answer 1

这是protected_attributes宝石，仍然在Rails 3＆gt; 4天左右徘徊，导致上述问题。

我在protected_attributes gem网站上发布了一个错误，他们回答说Rails 5不支持gem。

如果其他人有这个问题，那么Rails＆＃39;适当的＆＃39;可以在此处找到解决此问题的方法：How is attr_accessible used in Rails 4?或此处：http://api.rubyonrails.org/classes/ActionController/StrongParameters.html

感谢@oreoluwa指出我正确的方向

Ruby on Rails 5中的build（）发生了什么

1 个答案: