销毁用户模型后，无法重新添加用户模型答案

【问题标题】：After destroying user model, cannot add user model back in销毁用户模型后，无法重新添加用户模型
【发布时间】：2013-11-02 23:31:25
【问题描述】：

所以我在 Rails 上工作，对我的用户模型感到有点沮丧，所以我销毁了它（我也在使用可能是错误来源的设计）。在我的辩护中，我很累，很沮丧，而且有点醉了。我尝试使用简单的rails g scaffold user first:text last:text 将其重新添加，但在尝试生成模型时出现以下错误。如何备份这一切？

/home/action/.rvm/gems/ruby-2.0.0-p247/gems/activesupport-4.0.0/lib/active_support/inflector/methods.rb:226:in `const_get': uninitialized constant User (NameError)                  
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/activesupport-4.0.0/lib/active_support/inflector/methods.rb:226:in `block in constantize'                                                
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/activesupport-4.0.0/lib/active_support/inflector/methods.rb:224:in `each'                                                                
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/activesupport-4.0.0/lib/active_support/inflector/methods.rb:224:in `inject'                                                              
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/activesupport-4.0.0/lib/active_support/inflector/methods.rb:224:in `constantize'                                                         
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/devise-3.1.1/lib/devise.rb:285:in `get'                                                                 
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/devise-3.1.1/lib/devise/mapping.rb:77:in `to'                                                                  
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/devise-3.1.1/lib/devise/mapping.rb:72:in `modules'                                                             
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/devise-3.1.1/lib/devise/mapping.rb:89:in `routes'                                                              
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/devise-3.1.1/lib/devise/mapping.rb:156:in `default_used_route'                                                  
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/devise-3.1.1/lib/devise/mapping.rb:66:in `initialize'                                                          
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/devise-3.1.1/lib/devise.rb:319:in `new'                                                                 
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/devise-3.1.1/lib/devise.rb:319:in `add_mapping'                                                         
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/devise-3.1.1/lib/devise/rails/routes.rb:210:in `block in devise_for'                                                 
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/devise-3.1.1/lib/devise/rails/routes.rb:209:in `each'                                                                
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/devise-3.1.1/lib/devise/rails/routes.rb:209:in `devise_for'                                                          
        from /home/action/workspace/surrigo/config/routes.rb:2:in `block in <top (required)>'                                           
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/actionpack-4.0.0/lib/action_dispatch/routing/route_set.rb:316:in `instance_exec'                                                       
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/actionpack-4.0.0/lib/action_dispatch/routing/route_set.rb:316:in `eval_block'                                                          
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/actionpack-4.0.0/lib/action_dispatch/routing/route_set.rb:294:in `draw'                                                                
        from /home/action/workspace/surrigo/config/routes.rb:1:in `<top (required)>'                                                    
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/railties-4.0.0/lib/rails/application/routes_reloader.rb:40:in `block in load_paths'                                                 
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/railties-4.0.0/lib/rails/application/routes_reloader.rb:40:in `each'                                                                
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/railties-4.0.0/lib/rails/application/routes_reloader.rb:40:in `load_paths'                                                          
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/railties-4.0.0/lib/rails/application/routes_reloader.rb:16:in `reload!'                                                             
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/railties-4.0.0/lib/rails/application/routes_reloader.rb:26:in `block in updater'                                                    
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/activesupport-4.0.0/lib/active_support/file_update_checker.rb:75:in `call'                                                                
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/activesupport-4.0.0/lib/active_support/file_update_checker.rb:75:in `execute'                                                             
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/railties-4.0.0/lib/rails/application/routes_reloader.rb:27:in `updater'                                                             
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/railties-4.0.0/lib/rails/application/routes_reloader.rb:6:in `execute_if_updated'                                                  
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/railties-4.0.0/lib/rails/application/finisher.rb:69:in `block in <module:Finisher>'                                          
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/railties-4.0.0/lib/rails/initializable.rb:30:in `instance_exec'                                                       
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/railties-4.0.0/lib/rails/initializable.rb:30:in `run'                                                                 
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/railties-4.0.0/lib/rails/initializable.rb:55:in `block in run_initializers'                                           
        from /home/action/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/tsort.rb:150:in `block in tsort_each'                                                 
        from /home/action/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/tsort.rb:183:in `block (2 levels) in each_strongly_connected_component'               
        from /home/action/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/tsort.rb:219:in `each_strongly_connected_component_from'                              
        from /home/action/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/tsort.rb:182:in `block in each_strongly_connected_component'                          
        from /home/action/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/tsort.rb:180:in `each'                                                                
        from /home/action/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/tsort.rb:180:in `each_strongly_connected_component'                                   
        from /home/action/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/tsort.rb:148:in `tsort_each'                                                          
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/railties-4.0.0/lib/rails/initializable.rb:54:in `run_initializers'                                                    
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/railties-4.0.0/lib/rails/application.rb:215:in `initialize!'                                                         
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/railties-4.0.0/lib/rails/railtie/configurable.rb:30:in `method_missing'                                                      
        from /home/action/workspace/surrigo/config/environment.rb:13:in `<top (required)>'                                                          
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/railties-4.0.0/lib/rails/application.rb:189:in `require_environment!'                                                
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/railties-4.0.0/lib/rails/commands.rb:45:in `<top (required)>'                                                    
        from bin/rails:4:in `require'                                                                                                                                                                                                          
        from bin/rails:4:in `<main>'

【问题讨论】：

迁移弹出同样的错误
耙子中止！未初始化的常量用户 /home/action/.rvm/gems/ruby-2.0.0-p247/gems/activesupport-4.0.0/lib/active_support/inflector/methods.rb:226:in....
当我的控制台或服务器仍在运行时出现该错误。确保在迁移之前关闭它们。
它们都已被关闭。 :(
你在用 git 做版本控制吗？

标签： ruby-on-rails ruby devise

【解决方案1】：

从 routes.rb 中删除行 devise_for :users 并尝试运行 rails g scaffold user first:text last:text。它应该可以正常工作。

devise_for 方法需要 User 模型存在。因此，当您运行 rails scaffold 命令时，它无法加载 rails 环境

【讨论】：

【解决方案2】：

也许您与命名约定有冲突？

试试

rails g scaffold User first:text last:text

相反。您正在为 User 类生成模型（在 Ruby 中类是大写的 CamelCase）

【讨论】：