在尝试加载使用Rails构建的网站上的其中一个页面时获取NoMethodError。请参阅下面的完整堆栈跟踪。
如果我在生产线上将false更改为true
config.cache_classes = false
然后问题就消失了，但每次我对任何文件进行更改时都必须重新启动Rails服务器。看起来问题与检查数据库中列的类型有关，但我无法弄清楚如何解决它。
控制器操作：
def manage
@view_data = {}
if (@view_data[:product] = Product.find(params[:id])).nil?
raise ActionController::RoutingError.new('Not Found')
end
@view_data[:backlog] = Task.where("product_id = ? AND status < ?", params[:id], Task::STATUS_COMPLETED)
.page(params[:page]).per(10)
@view_data[:completed] = Task.where(product_id: params[:id], status: Task::STATUS_COMPLETED)
.page(params[:page]).per(10)
end
'tasks'表上有四列是datetime类型的 - 我认为这些列导致了问题，但我不完全确定。
完整堆栈跟踪：
NoMethodError - undefined method `type' for nil:NilClass:
activerecord (3.2.13) lib/active_record/attribute_methods/time_zone_conversion.rb:60:in `create_time_zone_conversion_attribute?'
activerecord (3.2.13) lib/active_record/attribute_methods/time_zone_conversion.rb:24:in `attribute_cast_code'
activerecord (3.2.13) lib/active_record/attribute_methods/serialization.rb:80:in `attribute_cast_code'
activerecord (3.2.13) lib/active_record/attribute_methods/read.rb:72:in `define_method_attribute'
activerecord (3.2.13) lib/active_record/attribute_methods/primary_key.rb:29:in `define_method_attribute'
activemodel (3.2.13) lib/active_model/attribute_methods.rb:267:in `block in define_attribute_method'
activemodel (3.2.13) lib/active_model/attribute_methods.rb:260:in `define_attribute_method'
activemodel (3.2.13) lib/active_model/attribute_methods.rb:256:in `block in define_attribute_methods'
activemodel (3.2.13) lib/active_model/attribute_methods.rb:256:in `define_attribute_methods'
activerecord (3.2.13) lib/active_record/attribute_methods.rb:66:in `block in define_attribute_methods'
activerecord (3.2.13) lib/active_record/attribute_methods.rb:63:in `define_attribute_methods'
activerecord (3.2.13) lib/active_record/attribute_methods.rb:168:in `respond_to?'
activesupport (3.2.13) lib/active_support/callbacks.rb:398:in `__run_callback'
activesupport (3.2.13) lib/active_support/callbacks.rb:385:in `_run_initialize_callbacks'
activesupport (3.2.13) lib/active_support/callbacks.rb:81:in `run_callbacks'
activerecord (3.2.13) lib/active_record/base.rb:501:in `initialize'
app/controllers/products_controller.rb:14:in `manage'
actionpack (3.2.13) lib/action_controller/metal/implicit_render.rb:4:in `send_action'
actionpack (3.2.13) lib/abstract_controller/base.rb:167:in `process_action'
actionpack (3.2.13) lib/action_controller/metal/rendering.rb:10:in `process_action'
actionpack (3.2.13) lib/abstract_controller/callbacks.rb:18:in `block in process_action'
activesupport (3.2.13) lib/active_support/callbacks.rb:425:in `_run__115665803178931257__process_action__4080704983955383443__callbacks'
activesupport (3.2.13) lib/active_support/callbacks.rb:405:in `__run_callback'
activesupport (3.2.13) lib/active_support/callbacks.rb:385:in `_run_process_action_callbacks'
activesupport (3.2.13) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (3.2.13) lib/abstract_controller/callbacks.rb:17:in `process_action'
actionpack (3.2.13) lib/action_controller/metal/rescue.rb:29:in `process_action'
actionpack (3.2.13) lib/action_controller/metal/instrumentation.rb:30:in `block in process_action'
activesupport (3.2.13) lib/active_support/notifications.rb:123:in `block in instrument'
activesupport (3.2.13) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (3.2.13) lib/active_support/notifications.rb:123:in `instrument'
actionpack (3.2.13) lib/action_controller/metal/instrumentation.rb:29:in `process_action'
actionpack (3.2.13) lib/action_controller/metal/params_wrapper.rb:207:in `process_action'
activerecord (3.2.13) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (3.2.13) lib/abstract_controller/base.rb:121:in `process'
actionpack (3.2.13) lib/abstract_controller/rendering.rb:45:in `process'
actionpack (3.2.13) lib/action_controller/metal.rb:203:in `dispatch'
actionpack (3.2.13) lib/action_controller/metal/rack_delegation.rb:14:in `dispatch'
actionpack (3.2.13) lib/action_controller/metal.rb:246:in `block in action'
actionpack (3.2.13) lib/action_dispatch/routing/route_set.rb:73:in `dispatch'
actionpack (3.2.13) lib/action_dispatch/routing/route_set.rb:36:in `call'
journey (1.0.4) lib/journey/router.rb:68:in `block in call'
journey (1.0.4) lib/journey/router.rb:56:in `call'
actionpack (3.2.13) lib/action_dispatch/routing/route_set.rb:612:in `call'
actionpack (3.2.13) lib/action_dispatch/middleware/best_standards_support.rb:17:in `call'
rack (1.4.5) lib/rack/etag.rb:23:in `call'
rack (1.4.5) lib/rack/conditionalget.rb:25:in `call'
actionpack (3.2.13) lib/action_dispatch/middleware/head.rb:14:in `call'
actionpack (3.2.13) lib/action_dispatch/middleware/params_parser.rb:21:in `call'
actionpack (3.2.13) lib/action_dispatch/middleware/flash.rb:242:in `call'
rack (1.4.5) lib/rack/session/abstract/id.rb:210:in `context'
rack (1.4.5) lib/rack/session/abstract/id.rb:205:in `call'
actionpack (3.2.13) lib/action_dispatch/middleware/cookies.rb:341:in `call'
activerecord (3.2.13) lib/active_record/query_cache.rb:64:in `call'
activerecord (3.2.13) lib/active_record/connection_adapters/abstract/connection_pool.rb:479:in `call'
actionpack (3.2.13) lib/action_dispatch/middleware/callbacks.rb:28:in `block in call'
activesupport (3.2.13) lib/active_support/callbacks.rb:405:in `_run__4157597128006817714__call__2909158845673021585__callbacks'
activesupport (3.2.13) lib/active_support/callbacks.rb:405:in `__run_callback'
activesupport (3.2.13) lib/active_support/callbacks.rb:385:in `_run_call_callbacks'
activesupport (3.2.13) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (3.2.13) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
actionpack (3.2.13) lib/action_dispatch/middleware/remote_ip.rb:31:in `call'
better_errors (0.9.0) lib/better_errors/middleware.rb:84:in `protected_app_call'
better_errors (0.9.0) lib/better_errors/middleware.rb:79:in `better_errors_call'
better_errors (0.9.0) lib/better_errors/middleware.rb:56:in `call'
actionpack (3.2.13) lib/action_dispatch/middleware/debug_exceptions.rb:16:in `call'
actionpack (3.2.13) lib/action_dispatch/middleware/show_exceptions.rb:56:in `call'
railties (3.2.13) lib/rails/rack/logger.rb:32:in `call_app'
railties (3.2.13) lib/rails/rack/logger.rb:16:in `block in call'
activesupport (3.2.13) lib/active_support/tagged_logging.rb:22:in `tagged'
railties (3.2.13) lib/rails/rack/logger.rb:16:in `call'
actionpack (3.2.13) lib/action_dispatch/middleware/request_id.rb:22:in `call'
rack (1.4.5) lib/rack/methodoverride.rb:21:in `call'
rack (1.4.5) lib/rack/runtime.rb:17:in `call'
activesupport (3.2.13) lib/active_support/cache/strategy/local_cache.rb:72:in `call'
rack (1.4.5) lib/rack/lock.rb:15:in `call'
actionpack (3.2.13) lib/action_dispatch/middleware/static.rb:63:in `call'
railties (3.2.13) lib/rails/engine.rb:479:in `call'
railties (3.2.13) lib/rails/application.rb:223:in `call'
rack (1.4.5) lib/rack/content_length.rb:14:in `call'
railties (3.2.13) lib/rails/rack/log_tailer.rb:17:in `call'
rack (1.4.5) lib/rack/handler/webrick.rb:59:in `service'
答案 0 :(得分：1)
在我的情况下，我有一个包含76个属性的模型，其中一个被命名为“class”，这导致了错误和异常。
所以，我做了：
并且有效： - ）
答案 1 :(得分：0)
您的错误似乎与this bug有关。有一些建议的解决方案可能与您的情况相关，或者您可以尝试this fix by alsemyonov。
答案 2 :(得分：0)
尝试设置config.autoload_once_paths