耙中止！未初始化的常量 User::UserGroup答案

【问题标题】：rake aborted! uninitialized constant User::UserGroup耙中止！未初始化的常量 User::UserGroup
【发布时间】：2013-03-04 06:20:04
【问题描述】：

我遇到了一个奇怪的问题，我的 rake 任务在我的本地机器上运行，但不在生产中。在 PRODUCTION 中尝试相同操作时出现以下错误

rake 中止！未初始化的常量 User::UserGroup

当我在上面运行跟踪时得到以下输出

$ RAILS_ENV=production bundle exec rake billing:invoices --trace

** Invoke billing:invoices (first_time)
** Invoke environment (first_time)
** Execute environment
** Execute billing:invoices
Building invoices
rake aborted!
uninitialized constant User::UserGroup
/usr/local/rvm/gems/ruby-1.9.3-p327/gems/activerecord-3.0.11/lib/active_record/base.rb:1205:in `compute_type'
/usr/local/rvm/gems/ruby-1.9.3-p327/gems/activerecord-3.0.11/lib/active_record/reflection.rb:162:in `klass'
/usr/local/rvm/gems/ruby-1.9.3-p327/gems/activerecord-3.0.11/lib/active_record/associations.rb:2107:in `initialize'
/usr/local/rvm/gems/ruby-1.9.3-p327/gems/activerecord-3.0.11/lib/active_record/associations.rb:1984:in `new'
/usr/local/rvm/gems/ruby-1.9.3-p327/gems/activerecord-3.0.11/lib/active_record/associations.rb:1984:in `build_join_association'
/usr/local/rvm/gems/ruby-1.9.3-p327/gems/activerecord-3.0.11/lib/active_record/associations.rb:1948:in `build'
/usr/local/rvm/gems/ruby-1.9.3-p327/gems/activerecord-3.0.11/lib/active_record/associations.rb:1956:in `block in build'
/usr/local/rvm/gems/ruby-1.9.3-p327/gems/activerecord-3.0.11/lib/active_record/associations.rb:1955:in `each'
/usr/local/rvm/gems/ruby-1.9.3-p327/gems/activerecord-3.0.11/lib/active_record/associations.rb:1955:in `build'
/usr/local/rvm/gems/ruby-1.9.3-p327/gems/activerecord-3.0.11/lib/active_record/associations.rb:1852:in `initialize'
/usr/local/rvm/gems/ruby-1.9.3-p327/gems/activerecord-3.0.11/lib/active_record/relation/query_methods.rb:246:in `new'
/usr/local/rvm/gems/ruby-1.9.3-p327/gems/activerecord-3.0.11/lib/active_record/relation/query_methods.rb:246:in `build_joins'
/usr/local/rvm/gems/ruby-1.9.3-p327/gems/activerecord-3.0.11/lib/active_record/relation/query_methods.rb:176:in `build_arel'
/usr/local/rvm/gems/ruby-1.9.3-p327/gems/activerecord-3.0.11/lib/active_record/relation/query_methods.rb:149:in `arel'
/usr/local/rvm/gems/ruby-1.9.3-p327/gems/activerecord-3.0.11/lib/active_record/relation/batches.rb:51:in `find_in_batches'
/usr/local/rvm/gems/ruby-1.9.3-p327/gems/activerecord-3.0.11/lib/active_record/relation/batches.rb:20:in `find_each'
/usr/local/rvm/gems/ruby-1.9.3-p327/gems/rake-0.9.2.2/lib/rake/task.rb:205:in `call'
/usr/local/rvm/gems/ruby-1.9.3-p327/gems/rake-0.9.2.2/lib/rake/task.rb:205:in `block in execute'
/usr/local/rvm/gems/ruby-1.9.3-p327/gems/rake-0.9.2.2/lib/rake/task.rb:200:in `each'
/usr/local/rvm/gems/ruby-1.9.3-p327/gems/rake-0.9.2.2/lib/rake/task.rb:200:in `execute'
/usr/local/rvm/gems/ruby-1.9.3-p327/gems/rake-0.9.2.2/lib/rake/task.rb:158:in `block in invoke_with_call_chain'
/usr/local/rvm/rubies/ruby-1.9.3-p327/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize'
/usr/local/rvm/gems/ruby-1.9.3-p327/gems/rake-0.9.2.2/lib/rake/task.rb:151:in `invoke_with_call_chain'
/usr/local/rvm/gems/ruby-1.9.3-p327/gems/rake-0.9.2.2/lib/rake/task.rb:144:in `invoke'
/usr/local/rvm/gems/ruby-1.9.3-p327/gems/rake-0.9.2.2/lib/rake/application.rb:116:in `invoke_task'
/usr/local/rvm/gems/ruby-1.9.3-p327/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `block (2 levels) in top_level'
/usr/local/rvm/gems/ruby-1.9.3-p327/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `each'
/usr/local/rvm/gems/ruby-1.9.3-p327/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `block in top_level'
/usr/local/rvm/gems/ruby-1.9.3-p327/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling'
/usr/local/rvm/gems/ruby-1.9.3-p327/gems/rake-0.9.2.2/lib/rake/application.rb:88:in `top_level'
/usr/local/rvm/gems/ruby-1.9.3-p327/gems/rake-0.9.2.2/lib/rake/application.rb:66:in `block in run'
/usr/local/rvm/gems/ruby-1.9.3-p327/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling'
/usr/local/rvm/gems/ruby-1.9.3-p327/gems/rake-0.9.2.2/lib/rake/application.rb:63:in `run'
/usr/local/rvm/gems/ruby-1.9.3-p327/gems/rake-0.9.2.2/bin/rake:33:in `<top (required)>'
/usr/local/rvm/gems/ruby-1.9.3-p327/bin/rake:23:in `load'
/usr/local/rvm/gems/ruby-1.9.3-p327/bin/rake:23:in `<main>'
Tasks: TOP => billing:invoices

奇怪的是它在我的本地机器上运行正常。有什么建议吗？

【问题讨论】：

在我的 rake 任务中，我使用环境变量 task :invoices => :environment do

标签： ruby-on-rails ruby ruby-on-rails-3 ruby-on-rails-3.1 rake-task

【解决方案1】：

我的猜测是您刚刚添加了一个名为 20120221123456_users.rb 的迁移，并且在其中，您有：

class SomeNameThatsNotUsers < ActiveRecord::Migration
  ...

当 Rails 执行迁移时，它希望执行定义类的文件，然后实例化类，并在该类实例上调用 #up 或 #down。 Rails 如何知道要实例化哪个类？它应该与文件名中数字前缀和下划线后面的部分相对应，所以对于像20120221123456_users.rb这样的文件名，类名必须是Users。

【讨论】：

【解决方案2】：

可以把失败的rake任务源码放上来吗？

通常你需要写这样的东西（以避免遇到 AR 问题）：

desc "我的任务描述" 任务：my_task_name =>：环境做 # 这里的任务代码结束

【讨论】：

感谢@rorra 通过在我的 config/production.rb 文件中从这个 config.threadsafe 更改它来解决这个问题！除非 ENV['THREADSAFE'] == 'off'，对此 --config.threadsafe!，config.dependency_loading = true if rails_rake_task。但仍然不清楚这会做什么？