Question

我一直在将我的应用程序从Rails 2.3.8升级到Rails 3。

在完成所有基本工作（配置，路由和新的AR API，用Devise替换Authlogic）并获得一些大部分静态页面以显示正常后，我的网站其余部分出现错误：

You have a nil object when you didn't expect it!
You might have expected an instance of Array.
The error occurred while evaluating nil.any?

首次引用SomeModel时，始终会显示此错误。例如，在我的news#index：

中

@news_story = NewsStory.new # gets called from before_filter

完整的堆栈跟踪如下。跟踪似乎表明我的app/models/news_story.rb中的模型没有加载。

我整天都在苦苦挣扎。有没有人知道发生了什么？

# stack trace:
activesupport (3.0.0) lib/active_support/dependencies.rb:497:in `load_missing_constant'
activesupport (3.0.0) lib/active_support/dependencies.rb:183:in `block in const_missing'
activesupport (3.0.0) lib/active_support/dependencies.rb:181:in `each'
activesupport (3.0.0) lib/active_support/dependencies.rb:181:in `const_missing'
app/controllers/news_controller.rb:82:in `new_post'
activesupport (3.0.0) lib/active_support/callbacks.rb:451:in `_run__810448074__process_action__85542351__callbacks'
activesupport (3.0.0) lib/active_support/callbacks.rb:409:in `_run_process_action_callbacks'
activesupport (3.0.0) lib/active_support/callbacks.rb:93:in `run_callbacks'
actionpack (3.0.0) lib/abstract_controller/callbacks.rb:17:in `process_action'
actionpack (3.0.0) lib/action_controller/metal/instrumentation.rb:30:in `block in process_action'
...

控制器操作：

class NewsController < ApplicationController
  before_filter :new_post_from_params, :only => :create
  before_filter :new_post, :only => [:index, :new]
  before_filter :find_post, :except => [:index, :create, :new]
  filter_access_to :all, :attribute_check => true

  def index
    @user = current_user
    @news = NewsStory.all
    respond_to do |format|
      format.html # index.html.erb
      format.xml { render :xml => @user.news }
    end
  end
  #...
  private

  def new_post_from_params
    @news_story = NewsStory.new(params[:news_story])
  end

  def new_post
    @news_story = NewsStory.new
  end

  def find_post
    @news_story = NewsStory.find(params[:id])
  end
end

其他信息：

app/models/news_story.rb
Gemfile
config/application.rb

Ruby版本：

~ $ ruby -v
ruby 1.9.2p0 (2010-08-18 revision 29036) [i686-linux]

从控制台创建新闻报道：

irb(main):001:0> NewsStory.new
=> #<NewsStory id: nil, title: nil, body: nil, user_id: nil, created_at: nil, updated_at: nil>

Answer 1

所以，问题是我在应用程序控制器中定义的一些parent_ *方法与新的ActionController方法有名称冲突，这在Rails 3中没有发生。

让我永远弄清楚，该死的

从Rails 2迁移到Rails 3问题（nil.any？）

其他信息：

1 个答案: