Question

我正在使用rails v3.2.2，当我尝试加载相关记录时，我收到一个奇怪的错误。

以下是我得到的终端输入/输出：

1.9.2-p318 :011 > Category.first
=> #<Category id: 1, ...>

1.9.2-p318 :013 > Category.first.articles
  Article Load (0.2ms)  SELECT `articles`.* FROM `articles` LIMIT 1
(Object doesn't support #inspect)

1.9.2-p318 :014 > Category.first.articles.first
  Category Load (0.2ms)  SELECT `categories`.* FROM `categories` LIMIT 1
NoMethodError: undefined method `scoped' for Category::Article:Module
    from /<USER_PATH>/.rvm/gems/ruby-1.9.2-p318/gems/activerecord-3.2.2/lib/active_record/associations/association.rb:123:in `target_scope'
    from /<USER_PATH>/.rvm/gems/ruby-1.9.2-p318/gems/activerecord-3.2.2/lib/active_record/associations/through_association.rb:15:in `target_scope'
    from /<USER_PATH>/.rvm/gems/ruby-1.9.2-p318/gems/activerecord-3.2.2/lib/active_record/associations/association.rb:87:in `scoped'
    from /<USER_PATH>/.rvm/gems/ruby-1.9.2-p318/gems/activerecord-3.2.2/lib/active_record/associations/collection_association.rb:569:in `first_or_last'
    from /<USER_PATH>/.rvm/gems/ruby-1.9.2-p318/gems/activerecord-3.2.2/lib/active_record/associations/collection_association.rb:101:in `first'
    from /<USER_PATH>/.rvm/gems/ruby-1.9.2-p318/gems/activerecord-3.2.2/lib/active_record/associations/collection_proxy.rb:46:in `first'
    from (irb):14
    from /<USER_PATH>/.rvm/gems/ruby-1.9.2-p318/gems/railties-3.2.2/lib/rails/commands/console.rb:47:in `start'
    from /<USER_PATH>/.rvm/gems/ruby-1.9.2-p318/gems/railties-3.2.2/lib/rails/commands/console.rb:8:in `start'
    from /<USER_PATH>/.rvm/gems/ruby-1.9.2-p318/gems/railties-3.2.2/lib/rails/commands.rb:41:in `<top (required)>'
    from script/rails:6:in `require'
    from script/rails:6:in `<main>'

在Category模型中，我有：

class Category < ActiveRecord::Base
  has_many :article_relationships,
    :class_name  => 'Category::Article::ArticleRelationship',
    :foreign_key => 'category_id'

  has_many :articles,
    :through     => :article_relationships,
    :source      => :article
end

在Category::Article::ArticleRelationship我有：

class Category::Article::ArticleRelationship < ActiveRecord::Base
  belongs_to :article,
    :class_name    => 'Article',
    :foreign_key   => 'article_id'
end

如何解决与Object doesn't support #inspect相关的问题？

注意：在同一个Category模型中，我有类似Category::Article::ArticleRelationship的声明（它与User类通过{{1}相关它不会导致问题。

Answer 1

您的应用中有两个名为Article的常量。一个是你的活跃记录类，顶级常量。另一个是模块 Category::Article。

执行belongs_to :article时，看起来rails开始在类中调用Article常量，因为它找到了错误的一个。这会造成各种各样的混乱，因为你显然不能互换地使用activerecord类和模块

设置:class_name => '::Article'会强制查找顶级Article类。

Answer 2

如果使用rails 4，问题来自protected_attributes gem，你需要将gem版本1.0.3升级到1.0.5，然后它才能工作。

Answer 3

问题似乎是通过在我的Category::Article::ArticleRelationship中声明以下内容来解决的：

class Category::Article::ArticleRelationship < ActiveRecord::Base
  belongs_to :article,
    :class_name    => '::Article', # note I added '::'
    :foreign_key   => 'article_id'
end

但我不明白为什么？

如何解决`对象不支持＃inspect`错误？

3 个答案: