无法预先加载类| Rails的4.2.5

我使用STI，并让所有子类需要。

但是在开发环境中，rails会执行延迟加载。所以Model.subclasses和Model.descendants总是返回[]

谷歌搜索把我送到这个问题：https://github.com/rails/rails/issues/3364

和上面的问题建议以下解决方案把尽可能初始化：

ActionDispatch::Reloader.to_prepare do 
    Rails.application.eager_load! 
end

而且对我获得关注例外：

/Users/vmac1/.rvm/gems/ruby-2.2.3/gems/activemodel-4.2.5/lib/active_model/validations/validates.rb:120:in `rescue in block in validates': Unknown validator: 'PersenceValidator' (ArgumentError) 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/activemodel-4.2.5/lib/active_model/validations/validates.rb:117:in `block in validates' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/activemodel-4.2.5/lib/active_model/validations/validates.rb:113:in `each' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/activemodel-4.2.5/lib/active_model/validations/validates.rb:113:in `validates' 
    from /Users/vmac1/rails_projects/survd/app/models/sub_service.rb:7:in `<class:SubService>' 
    from /Users/vmac1/rails_projects/survd/app/models/sub_service.rb:1:in `<top (required)>' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:457:in `load' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:457:in `block in load_file' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:647:in `new_constants_in' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:456:in `load_file' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:354:in `require_or_load' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:494:in `load_missing_constant' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:184:in `const_missing' 
    from /Users/vmac1/rails_projects/survd/app/models/buffet_service.rb:1:in `<top (required)>' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:457:in `load' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:457:in `block in load_file' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:647:in `new_constants_in' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:456:in `load_file' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:354:in `require_or_load' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:317:in `depend_on' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:233:in `require_dependency' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/railties-4.2.5/lib/rails/engine.rb:472:in `block (2 levels) in eager_load!' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/railties-4.2.5/lib/rails/engine.rb:471:in `each' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/railties-4.2.5/lib/rails/engine.rb:471:in `block in eager_load!' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/railties-4.2.5/lib/rails/engine.rb:469:in `each' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/railties-4.2.5/lib/rails/engine.rb:469:in `eager_load!' 
    from /Users/vmac1/rails_projects/survd/config/initializers/eagerload_subclasses.rb:2:in `block in <top (required)>' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/activesupport-4.2.5/lib/active_support/callbacks.rb:446:in `instance_exec' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/activesupport-4.2.5/lib/active_support/callbacks.rb:446:in `block in make_lambda' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/activesupport-4.2.5/lib/active_support/callbacks.rb:192:in `call' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/activesupport-4.2.5/lib/active_support/callbacks.rb:192:in `block in simple' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/activesupport-4.2.5/lib/active_support/callbacks.rb:504:in `call' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/activesupport-4.2.5/lib/active_support/callbacks.rb:504:in `block in call' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/activesupport-4.2.5/lib/active_support/callbacks.rb:504:in `each' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/activesupport-4.2.5/lib/active_support/callbacks.rb:504:in `call' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/activesupport-4.2.5/lib/active_support/callbacks.rb:92:in `__run_callbacks__' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/activesupport-4.2.5/lib/active_support/callbacks.rb:778:in `_run_prepare_callbacks' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/activesupport-4.2.5/lib/active_support/callbacks.rb:81:in `run_callbacks' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/actionpack-4.2.5/lib/action_dispatch/middleware/reloader.rb:83:in `prepare!' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/actionpack-4.2.5/lib/action_dispatch/middleware/reloader.rb:55:in `prepare!' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/railties-4.2.5/lib/rails/application/finisher.rb:50:in `block in <module:Finisher>' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/railties-4.2.5/lib/rails/initializable.rb:30:in `instance_exec' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/railties-4.2.5/lib/rails/initializable.rb:30:in `run' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/railties-4.2.5/lib/rails/initializable.rb:55:in `block in run_initializers' 
    from /Users/vmac1/.rvm/rubies/ruby-2.2.3/lib/ruby/2.2.0/tsort.rb:226:in `block in tsort_each' 
    from /Users/vmac1/.rvm/rubies/ruby-2.2.3/lib/ruby/2.2.0/tsort.rb:348:in `block (2 levels) in each_strongly_connected_component' 
    from /Users/vmac1/.rvm/rubies/ruby-2.2.3/lib/ruby/2.2.0/tsort.rb:429:in `each_strongly_connected_component_from' 
    from /Users/vmac1/.rvm/rubies/ruby-2.2.3/lib/ruby/2.2.0/tsort.rb:347:in `block in each_strongly_connected_component' 
    from /Users/vmac1/.rvm/rubies/ruby-2.2.3/lib/ruby/2.2.0/tsort.rb:345:in `each' 
    from /Users/vmac1/.rvm/rubies/ruby-2.2.3/lib/ruby/2.2.0/tsort.rb:345:in `call' 
    from /Users/vmac1/.rvm/rubies/ruby-2.2.3/lib/ruby/2.2.0/tsort.rb:345:in `each_strongly_connected_component' 
    from /Users/vmac1/.rvm/rubies/ruby-2.2.3/lib/ruby/2.2.0/tsort.rb:224:in `tsort_each' 
    from /Users/vmac1/.rvm/rubies/ruby-2.2.3/lib/ruby/2.2.0/tsort.rb:203:in `tsort_each' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/railties-4.2.5/lib/rails/initializable.rb:54:in `run_initializers' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/railties-4.2.5/lib/rails/application.rb:352:in `initialize!' 
    from /Users/vmac1/rails_projects/survd/config/environment.rb:5:in `<top (required)>' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:274:in `require' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:274:in `block in require' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:240:in `load_dependency' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:274:in `require' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/spring-1.6.3/lib/spring/application.rb:92:in `preload' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/spring-1.6.3/lib/spring/application.rb:143:in `serve' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/spring-1.6.3/lib/spring/application.rb:131:in `block in run' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/spring-1.6.3/lib/spring/application.rb:125:in `loop' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/spring-1.6.3/lib/spring/application.rb:125:in `run' 
    from /Users/vmac1/.rvm/gems/ruby-2.2.3/gems/spring-1.6.3/lib/spring/application/boot.rb:18:in `<top (required)>' 
    from /Users/vmac1/.rvm/rubies/ruby-2.2.3/lib/ruby/2.2.0/rubygems/core_ext/kernel_require.rb:54:in `require' 
    from /Users/vmac1/.rvm/rubies/ruby-2.2.3/lib/ruby/2.2.0/rubygems/core_ext/kernel_require.rb:54:in `require' 
    from -e:1:in `<main>'

来源

2016-02-14 Sachin

你在某处遇到了一个错字（persence vs presence）吗？ –

否。当我删除上述初始值设定项时，异常会执行 – Sachin

急切加载可能（根据定义）导致s模型通常不会加载，并且会加载错字。异常消息是奇怪的，否则 –

正如其他人所说笔误，实际的错误是一个验证错字。但是对于原始问题，Rails 4.2急切地加载了生产中的所有类by default，因此您只需更改其他环境中的eager_load和cache_classes设置即可获得相同的行为。但是，这会使开发更令人不快，因为每次更改代码时都必须重新启动服务器。

您试图通过列出所有子类来解决的底层问题是什么？可能有另一种设计可以避免这种要求。

来源

2016-02-14 18:09:44 Ari

的persence代替presence

来源

2016-02-14 15:40:35 Sachin

无法预先加载类| Rails的4.2.5

回答

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