我看到我的全新Rails 3.1 rc5应用程序在生产模式下运行时会出现一些随机崩溃事件。后端是nginx，有3个瘦实例。
[Exception] users#show (NoMethodError) "undefined method `text?' for nil:NilClass"
undefined method `text?' for nil:NilClass
activerecord (3.1.0.rc5) lib/active_record/validations/uniqueness.rb:57:in `build_relation'
我打开了log：debug。但是唯一的信息是“内部服务器错误”以前有人见过这个吗？身份地图被改为......
如果我重新启动瘦机，Rails几个小时就会毫无问题地运行。
Update1：看起来几乎所有我的控制器操作都会随机生成此错误。今天早上我收到了一封上面有错误的电子邮件。如果我按照链接，生成页面没有问题。
我想知道这个问题是否与从cookie加载用户的问题有关？
class ApplicationController < ActionController::Base
protect_from_forgery
layout "content_with_sidebar"
before_filter :system
rescue_from CanCan::AccessDenied do |exception|
flash[:warning] = "Ingen adgang!"
redirect_to root_url
end
def system
if current_user
unless current_user.email_verified == "t"
flash[:warning] = 'Please activate your account.'
end
current_user.last_seen = Time.now
current_user.save # <--- line 18
@new_messages = Message.new_messages(current_user).count
end
end
helper_method :current_user
private
def current_user
if cookies[:auth_token]
@current_user ||= User.find_by_auth_token!(cookies[:auth_token])
end
end
end
来自用户的代码示例＃Show
class UsersController < ApplicationController
before_filter :ensure_current_user_url, :only => :show
load_and_authorize_resource
def ensure_current_user_url
@user = User.find(params[:id].downcase)
redirect_to @user, :status => :moved_permanently unless @user.friendly_id_status.best?
end
def show
if params[:do] == "guestbook"
@comment = @user.comments.new
@comments = @user.comments.includes(:author).order("created_at DESC").all(:limit => 5)
else
@recent_comments = @user.comments(:order => "created_at DESC")
end
@arts = @user.arts.order("created_at desc").includes([:author, :category]).page(params[:page]).per(24)
render :layout => "content_with_sidebar_whitebox"
end
UPDATE2 这是我添加调试时得到的信息。
************** username
************** ["id", "username", "email", "email_verified", "birthday", "firstname", "lastname", "phone", "website", "profile", "last_seen", "administrator", "cached_slug", "password_salt", "crypted_password", "avatar", "avatar_cache", "comments_count", "arts_count", "auth_token", "account_activation_token", "account_activation_sent_at", "password_reset_token", "password_reset_sent_at", "created_at", "updated_at", "cheapest", "most_expensive"]
************** email
************** ["id", "username", "email", "email_verified", "birthday", "firstname", "lastname", "phone", "website", "profile", "last_seen", "administrator", "cached_slug", "password_salt", "crypted_password", "avatar", "avatar_cache", "comments_count", "arts_count", "auth_token", "account_activation_token", "account_activation_sent_at", "password_reset_token", "password_reset_sent_at", "created_at", "updated_at", "cheapest", "most_expensive"]
这是今天早上崩溃的完整堆栈跟踪。
Started GET "/messages" for filtered-ip at 2011-08-15 12:13:17 -0400
Processing by MessagesController#index as HTML
User Load (1.5ms) SELECT "users".* FROM "users" WHERE "users"."auth_token" = '380e8b776cb8e3c5fd7d8b777b6d2073' ORDER BY last_seen desc LIMIT 1
(0.3ms) BEGIN
(0.9ms) SELECT 1 FROM "users" WHERE ("users"."username" = 'samia-dk' AND "users"."id" != 483) LIMIT 1
(0.9ms) SELECT 1 FROM "users" WHERE ("users"."email" = 'mail@filtered.dk' AND "users"."id" != 483) LIMIT 1
(0.4ms) ROLLBACK
Completed 500 Internal Server Error in 14ms
Rendered /usr/local/rvm/gems/ruby-1.9.2-p290-dev@myblog5/gems/exception_notification_rails3-1.2.0/lib/exception_notifier/views/exception_notifier/_request.text.erb (0.8ms)
Rendered /usr/local/rvm/gems/ruby-1.9.2-p290-dev@myblog5/gems/exception_notification_rails3-1.2.0/lib/exception_notifier/views/exception_notifier/_title.text.erb (0.4ms)
Rendered /usr/local/rvm/gems/ruby-1.9.2-p290-dev@myblog5/gems/exception_notification_rails3-1.2.0/lib/exception_notifier/views/exception_notifier/_session.text.erb (0.9ms)
Rendered /usr/local/rvm/gems/ruby-1.9.2-p290-dev@myblog5/gems/exception_notification_rails3-1.2.0/lib/exception_notifier/views/exception_notifier/_title.text.erb (0.1ms)
Rendered /usr/local/rvm/gems/ruby-1.9.2-p290-dev@myblog5/gems/exception_notification_rails3-1.2.0/lib/exception_notifier/views/exception_notifier/_environment.text.erb (55.3ms)
Rendered /usr/local/rvm/gems/ruby-1.9.2-p290-dev@myblog5/gems/exception_notification_rails3-1.2.0/lib/exception_notifier/views/exception_notifier/_title.text.erb (0.3ms)
Rendered /usr/local/rvm/gems/ruby-1.9.2-p290-dev@myblog5/gems/exception_notification_rails3-1.2.0/lib/exception_notifier/views/exception_notifier/_backtrace.text.erb (1.7ms)
Rendered /usr/local/rvm/gems/ruby-1.9.2-p290-dev@myblog5/gems/exception_notification_rails3-1.2.0/lib/exception_notifier/views/exception_notifier/_title.text.erb (0.2ms)
Rendered /usr/local/rvm/gems/ruby-1.9.2-p290-dev@myblog5/gems/exception_notification_rails3-1.2.0/lib/exception_notifier/views/exception_notifier/exception_notification.text.erb (71.8ms)
Sent mail to some@mail.com (3072ms)
Date: Mon, 15 Aug 2011 12:13:18 -0400
From: Exception Notifier <robot@myblog.dk>
To: some@mail.com
Message-ID: <4e49459e3709a_792610c8826e4@li267-196.mail>
Subject: [Exception] messages#index (NoMethodError) "undefined method `text?'
for nil:NilClass"
Mime-Version: 1.0
Content-Type: text/plain;
charset=UTF-8
Content-Transfer-Encoding: 7bit
A NoMethodError occurred in messages#index:
undefined method `text?' for nil:NilClass
config/initializers/some_debug.rb:6:in `build_relation'
-------------------------------
Request:
-------------------------------
* URL : http://www.myblog.dk/messages
* IP address: filtered
* Parameters: {"action"=>"index", "controller"=>"messages"}
* Rails root: /home/atmorell/Dropbox/myblog5
-------------------------------
Session:
-------------------------------
* session id: nil
* data: {"_csrf_token"=>"filtered=",
"user_credentials"=>true,
"user_credentials_id"=>483}
-------------------------------
Environment:
-------------------------------
* GATEWAY_INTERFACE : CGI/1.2
* HTTP_ACCEPT : text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
* HTTP_ACCEPT_CHARSET : ISO-8859-1,utf-8;q=0.7,*;q=0.7
* HTTP_ACCEPT_ENCODING : gzip, deflate
* HTTP_ACCEPT_LANGUAGE : en,da;q=0.7,en-us;q=0.3
* HTTP_CONNECTION : close
* HTTP_COOKIE : __utma=52641074.268317442.1313423882.1313423882.1313423882.1; __utmb=52641074.53.10.1313423882; __utmc=52641074; __utmz=52641074.1313423882.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none); _myblog_session5=ed471364634fcd3b44c7bb0eae758b14; user_credentials=true%3A%3A483; auth_token=filtered
* HTTP_HOST : www.myblog.dk
* HTTP_REFERER : http://www.myblog.dk/messages/new
* HTTP_USER_AGENT : Mozilla/5.0 (Windows NT 6.1; WOW64; rv:5.0) Gecko/20100101 Firefox/5.0
* HTTP_VERSION : HTTP/1.0
* PATH_INFO : /messages
* QUERY_STRING :
* REMOTE_ADDR : filtered-ip
* REQUEST_METHOD : GET
* REQUEST_PATH : /messages
* REQUEST_URI : /messages
* SCRIPT_NAME :
* SERVER_NAME : www.myblog.dk
* SERVER_PORT : 80
* SERVER_PROTOCOL : HTTP/1.1
* SERVER_SOFTWARE : thin 1.2.11 codename Bat-Shit Crazy
* action_controller.instance : messages#index
* action_dispatch.cookies : #<ActionDispatch::Cookies::CookieJar:0x00000008766b98>
* action_dispatch.parameter_filter : [:password, /RAW_POST_DATA/]
* action_dispatch.remote_ip : filtered-ip
* action_dispatch.request.content_type :
* action_dispatch.request.formats : [text/html]
* action_dispatch.request.parameters : {"action"=>"index", "controller"=>"messages"}
* action_dispatch.request.path_parameters : {:action=>"index", :controller=>"messages"}
* action_dispatch.request.query_parameters : {}
* action_dispatch.request.request_parameters: {}
* action_dispatch.routes : #<ActionDispatch::Routing::RouteSet:0x00000002eaf658>
* action_dispatch.secret_token : 93479c2e63bdb766a51f18397345cdc9a8b22ee009334171207f6b0bc2e71105d1f849de46e34965febc3b178cea662e89986e73d8922ec4915c44dca6ae4000
* action_dispatch.show_exceptions : true
* async.callback : #<Method: Thin::Connection#post_process>
* async.close : #<EventMachine::DefaultDeferrable:0x000000087809a8>
* exception_notifier.options : {:email_prefix=>"[Exception] ", :sender_address=>"\"Exception Notifier\" <robot@myblog.dk>", :exception_recipients=>["some@mail.com"], :ignore_exceptions=>[ActiveRecord::RecordNotFound, AbstractController::ActionNotFound, ActionController::RoutingError]}
* rack-cache.allow_reload : false
* rack-cache.allow_revalidate : false
* rack-cache.cache_key : Rack::Cache::Key
* rack-cache.default_ttl : 0
* rack-cache.entitystore : rails:/
* rack-cache.metastore : rails:/
* rack-cache.private_headers : ["Authorization", "Cookie"]
* rack-cache.storage : #<Rack::Cache::Storage:0x000000029e9b50>
* rack-cache.verbose : true
* rack.errors : #<IO:0x00000000c27860>
* rack.input : #<StringIO:0x00000008784c10>
* rack.multiprocess : false
* rack.multithread : false
* rack.request.cookie_hash : {"__utma"=>"52641074.268317442.1313423882.1313423882.1313423882.1", "__utmb"=>"52641074.53.10.1313423882", "__utmc"=>"52641074", "__utmz"=>"52641074.1313423882.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none)", "_myblog_session5"=>"ed471364634fcd3b44c7bb0eae758b14", "user_credentials"=>"true::483", "auth_token"=>"filtered"}
* rack.request.cookie_string : __utma=52641074.268317442.1313423882.1313423882.1313423882.1; __utmb=52641074.53.10.1313423882; __utmc=52641074; __utmz=52641074.1313423882.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none); _myblog_session5=ed471364634fcd3b44c7bb0eae758b14; user_credentials=true%3A%3A483; auth_token=filtered
* rack.request.query_hash : {}
* rack.request.query_string :
* rack.run_once : false
* rack.session : {"_csrf_token"=>"jlK/filtered=", "user_credentials"=>true, "user_credentials_id"=>483}
* rack.session.options : {:key=>"_myblog_session5", :path=>"/", :domain=>nil, :expire_after=>nil, :secure=>false, :httponly=>true, :defer=>false, :renew=>false, :id=>"ed471364634fcd3b44c7bb0eae758b14"}
* rack.session.record : #<ActiveRecord::SessionStore::Session:0x000000087762f0>
* rack.url_scheme : http
* rack.version : [1, 0]
* Process: 1938
* Server : li267-196
-------------------------------
Backtrace:
-------------------------------
config/initializers/some_debug.rb:6:in `build_relation'
activerecord (3.1.0.rc5) lib/active_record/validations/uniqueness.rb:25:in `validate_each'
activemodel (3.1.0.rc5) lib/active_model/validator.rb:153:in `block in validate'
activemodel (3.1.0.rc5) lib/active_model/validator.rb:150:in `each'
activemodel (3.1.0.rc5) lib/active_model/validator.rb:150:in `validate'
activesupport (3.1.0.rc5) lib/active_support/callbacks.rb:302:in `_callback_before_483'
activesupport (3.1.0.rc5) lib/active_support/callbacks.rb:622:in `_run_validate_callbacks'
activesupport (3.1.0.rc5) lib/active_support/callbacks.rb:81:in `run_callbacks'
activemodel (3.1.0.rc5) lib/active_model/validations.rb:212:in `run_validations!'
activemodel (3.1.0.rc5) lib/active_model/validations/callbacks.rb:53:in `block in run_validations!'
activesupport (3.1.0.rc5) lib/active_support/callbacks.rb:401:in `_run_validation_callbacks'
activesupport (3.1.0.rc5) lib/active_support/callbacks.rb:81:in `run_callbacks'
activemodel (3.1.0.rc5) lib/active_model/validations/callbacks.rb:53:in `run_validations!'
activemodel (3.1.0.rc5) lib/active_model/validations.rb:179:in `valid?'
activerecord (3.1.0.rc5) lib/active_record/validations.rb:69:in `valid?'
activerecord (3.1.0.rc5) lib/active_record/validations.rb:77:in `perform_validations'
activerecord (3.1.0.rc5) lib/active_record/validations.rb:50:in `save'
activerecord (3.1.0.rc5) lib/active_record/attribute_methods/dirty.rb:22:in `save'
activerecord (3.1.0.rc5) lib/active_record/transactions.rb:241:in `block (2 levels) in save'
activerecord (3.1.0.rc5) lib/active_record/transactions.rb:295:in `block in with_transaction_returning_status'
activerecord (3.1.0.rc5) lib/active_record/connection_adapters/abstract/database_statements.rb:183:in `transaction'
activerecord (3.1.0.rc5) lib/active_record/transactions.rb:208:in `transaction'
activerecord (3.1.0.rc5) lib/active_record/transactions.rb:293:in `with_transaction_returning_status'
activerecord (3.1.0.rc5) lib/active_record/transactions.rb:241:in `block in save'
activerecord (3.1.0.rc5) lib/active_record/transactions.rb:252:in `rollback_active_record_state!'
activerecord (3.1.0.rc5) lib/active_record/transactions.rb:240:in `save'
app/controllers/application_controller.rb:18:in `system'
activesupport (3.1.0.rc5) lib/active_support/callbacks.rb:430:in `_run__163591495713425608__process_action__3187008165500041637__callbacks'
activesupport (3.1.0.rc5) lib/active_support/callbacks.rb:386:in `_run_process_action_callbacks'
activesupport (3.1.0.rc5) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (3.1.0.rc5) lib/abstract_controller/callbacks.rb:17:in `process_action'
actionpack (3.1.0.rc5) lib/action_controller/metal/rescue.rb:17:in `process_action'
actionpack (3.1.0.rc5) lib/action_controller/metal/instrumentation.rb:30:in `block in process_action'
activesupport (3.1.0.rc5) lib/active_support/notifications.rb:55:in `block in instrument'
activesupport (3.1.0.rc5) lib/active_support/notifications/instrumenter.rb:21:in `instrument'
activesupport (3.1.0.rc5) lib/active_support/notifications.rb:55:in `instrument'
actionpack (3.1.0.rc5) lib/action_controller/metal/instrumentation.rb:29:in `process_action'
actionpack (3.1.0.rc5) lib/action_controller/metal/params_wrapper.rb:202:in `process_action'
activerecord (3.1.0.rc5) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (3.1.0.rc5) lib/abstract_controller/base.rb:121:in `process'
actionpack (3.1.0.rc5) lib/abstract_controller/rendering.rb:45:in `process'
actionpack (3.1.0.rc5) lib/action_controller/metal.rb:193:in `dispatch'
actionpack (3.1.0.rc5) lib/action_controller/metal/rack_delegation.rb:14:in `dispatch'
actionpack (3.1.0.rc5) lib/action_controller/metal.rb:236:in `block in action'
actionpack (3.1.0.rc5) lib/action_dispatch/routing/route_set.rb:65:in `call'
actionpack (3.1.0.rc5) lib/action_dispatch/routing/route_set.rb:65:in `dispatch'
actionpack (3.1.0.rc5) lib/action_dispatch/routing/route_set.rb:29:in `call'
rack-mount (0.8.2) lib/rack/mount/route_set.rb:152:in `block in call'
rack-mount (0.8.2) lib/rack/mount/code_generation.rb:96:in `block in recognize'
rack-mount (0.8.2) lib/rack/mount/code_generation.rb:68:in `optimized_each'
rack-mount (0.8.2) lib/rack/mount/code_generation.rb:95:in `recognize'
rack-mount (0.8.2) lib/rack/mount/route_set.rb:141:in `call'
actionpack (3.1.0.rc5) lib/action_dispatch/routing/route_set.rb:531:in `call'
oa-core (0.2.6) lib/omniauth/strategy.rb:44:in `call!'
oa-core (0.2.6) lib/omniauth/strategy.rb:30:in `call'
oa-core (0.2.6) lib/omniauth/strategy.rb:44:in `call!'
oa-core (0.2.6) lib/omniauth/strategy.rb:30:in `call'
oa-core (0.2.6) lib/omniauth/strategy.rb:44:in `call!'
oa-core (0.2.6) lib/omniauth/strategy.rb:30:in `call'
oa-core (0.2.6) lib/omniauth/builder.rb:30:in `call'
exception_notification_rails3 (1.2.0) lib/exception_notifier.rb:34:in `call'
actionpack (3.1.0.rc5) lib/action_dispatch/middleware/best_standards_support.rb:17:in `call'
rack (1.3.2) lib/rack/etag.rb:23:in `call'
rack (1.3.2) lib/rack/conditionalget.rb:25:in `call'
actionpack (3.1.0.rc5) lib/action_dispatch/middleware/head.rb:14:in `call'
actionpack (3.1.0.rc5) lib/action_dispatch/middleware/params_parser.rb:21:in `call'
actionpack (3.1.0.rc5) lib/action_dispatch/middleware/flash.rb:243:in `call'
rack (1.3.2) lib/rack/session/abstract/id.rb:195:in `context'
rack (1.3.2) lib/rack/session/abstract/id.rb:190:in `call'
actionpack (3.1.0.rc5) lib/action_dispatch/middleware/cookies.rb:326:in `call'
activerecord (3.1.0.rc5) lib/active_record/query_cache.rb:62:in `call'
activerecord (3.1.0.rc5) lib/active_record/connection_adapters/abstract/connection_pool.rb:466:in `call'
actionpack (3.1.0.rc5) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call'
activesupport (3.1.0.rc5) lib/active_support/callbacks.rb:392:in `_run_call_callbacks'
activesupport (3.1.0.rc5) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (3.1.0.rc5) lib/action_dispatch/middleware/callbacks.rb:28:in `call'
rack (1.3.2) lib/rack/sendfile.rb:101:in `call'
actionpack (3.1.0.rc5) lib/action_dispatch/middleware/remote_ip.rb:48:in `call'
actionpack (3.1.0.rc5) lib/action_dispatch/middleware/show_exceptions.rb:47:in `call'
railties (3.1.0.rc5) lib/rails/rack/logger.rb:13:in `call'
rack (1.3.2) lib/rack/methodoverride.rb:24:in `call'
rack (1.3.2) lib/rack/runtime.rb:17:in `call'
activesupport (3.1.0.rc5) lib/active_support/cache/strategy/local_cache.rb:72:in `call'
rack (1.3.2) lib/rack/lock.rb:15:in `call'
actionpack (3.1.0.rc5) lib/action_dispatch/middleware/static.rb:53:in `call'
rack-cache (1.0.2) lib/rack/cache/context.rb:132:in `forward'
rack-cache (1.0.2) lib/rack/cache/context.rb:243:in `fetch'
rack-cache (1.0.2) lib/rack/cache/context.rb:181:in `lookup'
rack-cache (1.0.2) lib/rack/cache/context.rb:65:in `call!'
rack-cache (1.0.2) lib/rack/cache/context.rb:50:in `call'
railties (3.1.0.rc5) lib/rails/engine.rb:455:in `call'
railties (3.1.0.rc5) lib/rails/railtie/configurable.rb:30:in `method_missing'
thin (1.2.11) lib/thin/connection.rb:84:in `block in pre_process'
thin (1.2.11) lib/thin/connection.rb:82:in `catch'
thin (1.2.11) lib/thin/connection.rb:82:in `pre_process'
thin (1.2.11) lib/thin/connection.rb:57:in `process'
thin (1.2.11) lib/thin/connection.rb:42:in `receive_data'
eventmachine (0.12.10) lib/eventmachine.rb:256:in `run_machine'
eventmachine (0.12.10) lib/eventmachine.rb:256:in `run'
thin (1.2.11) lib/thin/backends/base.rb:61:in `start'
thin (1.2.11) lib/thin/server.rb:159:in `start'
thin (1.2.11) lib/thin/controllers/controller.rb:86:in `start'
thin (1.2.11) lib/thin/runner.rb:185:in `run_command'
thin (1.2.11) lib/thin/runner.rb:151:in `run!'
thin (1.2.11) bin/thin:6:in `<top (required)>'
/usr/local/rvm/gems/ruby-1.9.2-p290-dev@myblog5/bin/thin:19:in `load'
/usr/local/rvm/gems/ruby-1.9.2-p290-dev@myblog5/bin/thin:19:in `<main>'
NoMethodError (undefined method `text?' for nil:NilClass):
config/initializers/some_debug.rb:6:in `build_relation'
app/controllers/application_controller.rb:18:in `system'
User.rb
# -*- encoding : utf-8 -*-
class User < ActiveRecord::Base
attr_accessible :username, :email, :birthday, :firstname, :lastname, :phone, :website, :profile, :avatar, :password, :avatar_cache, :name, :last_seen, :arts_count, :cheapest, :most_expensive #, :email_verified, :crypted_password, :password_salt, :administrator, :id
# Virtual attributes
attr_accessor :password, :password_confirmation
belongs_to :cheapest, :class_name => "Art", :foreign_key => :cheapest
belongs_to :most_expensive, :class_name => "Art", :foreign_key => :most_expensive
has_many :blogs, :dependent => :destroy
has_many :arts, :dependent => :destroy
has_many :authentications, :dependent => :destroy
has_friendly_id :username, :use_slug => true
has_many :comments, :as => :commentable, :validate => :false
mount_uploader :avatar, AvatarUploader
before_save :encrypt_password
before_create { generate_token(:auth_token) }
after_create { send_account_activation }
validates_uniqueness_of :username, :email
validates_presence_of :username, :email
validate :password_length_without_authentications
validates_format_of :username, :with => /^[-a-z\d_]+$/, :message => "kun små bogstaver, tal og bindestreger. f.eks. galleri-toke"
validates_length_of :username, :maximum=>30, :message=>"Dit brugernavn må max være 30 karakter."
validates_length_of :username, :minimum=>3, :message=>"Dit brugernavn skal minimum være 3 karakter."
validates_format_of :email, :with => /\A([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})\Z/i
default_scope :order => "last_seen desc" #, :conditions => "username NOT LIKE 'robot'"
scope :with_arts, where("arts_count > 0")
...
每次用户刷新页面时，我都会更新last_seen列并保存logged_in用户。出于某种原因，储蓄中断了。我无法在我的开发服务器上重现这一点。
答案 0 :(得分：18)
解决方案：如果您的验证线说明了这一点......
validates :tag, :uniqueness => {:scope => :post}
...然后将其更改为引用列名而不是像这样的关联名...
validates :tag_id, :uniqueness => {:scope => :post_id}
我在rails 3.1.0.rc5中重新创建了您的失败并生成了相同的错误消息。简短的解释是build_relation方法中的代码需要一个文字列名，而不是一个关联名。
有关包含代码段的更详尽说明，请参阅我的博客http://thetenelements.blogspot.com/2011/08/undefined-method-text-for-nilnilclass.html
答案 1 :(得分：4)
Luke Griffiths给了你大部分答案。本质就是这个，你在某处有一个唯一性验证。根据你的评论，你唯一拥有的就是这个：
validates_uniqueness_of :body, :scope => [:commentable_id, :user_id], :message => "Duplicate record.."
如果是这种情况，那么我们必须假设它是罪魁祸首（它有助于了解验证的模型，也有助于查看用户模型代码的相关部分以及相关部分。发现验证的模型）。但无论我们仍然可以猜测你的问题是什么。
您遇到的问题发生在第57行的rails source build_relation中的rails/activerecord/lib/active_record/validations/uniqueness.rb方法中。此方法尝试根据属性名称查找列，然后尝试看它是不是文字。发生错误是因为它获取的属性似乎不在列散列中，而column的值为零。
在另一个答案中建议您在build_relation方法中输出一些调试信息。这不是一个坏主意（你真正需要知道的是columns_hash中的键是什么以及传递给方法的属性的值是什么），这是你如何做到的。在config/initializers中创建初始值设定项，我们称之为debugging_stuff.rb。在那里你可以提出以下内容：
ActiveRecord::Validations::UniquenessValidator.class_eval do
def build_relation(klass, table, attribute, value) #:nodoc:
puts "************** #{attribute}"
puts "************** #{klass.columns_hash.keys.inspect}"
column = klass.columns_hash[attribute.to_s]
value = column.limit ? value.to_s.mb_chars[0, column.limit] : value.to_s if column.text?
if !options[:case_sensitive] && value && column.text?
# will use SQL LOWER function before comparison
relation = table[attribute].lower.eq(table.lower(value))
else
value = klass.connection.case_sensitive_modifier(value)
relation = table[attribute].eq(value)
end
relation
end
end
我们要找的是找出columns_hash中没有任何键与传递的属性值匹配的时间。
如果上面的唯一性验证器确实是你唯一的，它应该是那里的三个属性之一（:body, :commentable_id, :user_id）。我的钱在:body，但我错了。 :body是否引用另一个模型。如果确实如此，也许应该像卢克格里菲斯所说的那样:body_id。如果您仍然无法找到问题，则需要提供更多调试信息，如完整堆栈跟踪和相关模型的代码（用户等） - 我们已经尽可能地利用我们所拥有的信息。
答案 2 :(得分：2)
如果仍然无法解决此问题，请自行为build_relation方法添加一些调试。只需让它将一些数据写入控制台，看看它实际出错的地方。
更改
def build_relation(klass, table, attribute, value) #:nodoc:
column = klass.columns_hash[attribute.to_s]
value = column.limit ? value.to_s.mb_chars[0, column.limit] : value.to_s if column.text?
到
def build_relation(klass, table, attribute, value) #:nodoc:
puts "build_relation klass: #{klass.inspect}"
puts "build_relation table: #{table.inspect}"
puts "build_relation attribute: #{attribute.inspect}"
puts "build_relation value: #{value.inspect}"
puts "build_relation columns_hash: #{klass.columns_hash.inspect}"
column = klass.columns_hash[attribute.to_s]
value = column.limit ? value.to_s.mb_chars[0, column.limit] : value.to_s if column.text?
然后你至少会知道导致这种情况的属性。现在希望每次出错都是一样的......