無法預先加載類| Rails的4.2.5

我使用STI，並讓所有子類需要。

但是在開發環境中，rails會執行延遲加載。所以Model.subclasses和Model.descendants總是返回[]

谷歌搜索把我送到這個問題：https://github.com/rails/rails/issues/3364

和上面的問題建議以下解決方案把儘可能初始化：

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

而且對我獲得關注例外：

/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>'

來源

2016-02-14 Sachin

你在某處遇到了一個錯字（persence vs presence）嗎？ –

否。當我刪除上述初始值設定項時，異常會執行 – Sachin

急切加載可能（根據定義）導致s模型通常不會加載，並且會加載錯字。異常消息是奇怪的，否則 –

正如其他人所說筆誤，實際的錯誤是一個驗證錯字。但是對於原始問題，Rails 4.2急切地加載了生產中的所有類by default，因此您只需更改其他環境中的eager_load和cache_classes設置即可獲得相同的行爲。但是，這會使開發更令人不快，因爲每次更改代碼時都必須重新啓動服務器。

您試圖通過列出所有子類來解決的底層問題是什麼？可能有另一種設計可以避免這種要求。

來源

2016-02-14 18:09:44 Ari

的persence代替presence

來源

2016-02-14 15:40:35 Sachin

無法預先加載類| Rails的4.2.5

回答

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