【发布时间】：2010-11-26 09:32:42
【问题描述】：
我正在尝试将我的应用程序从 Rails 2.3.5 升级到 Rails 3.0.3。
型号：
项目.rb
has_many :project_roles, :dependent => :destroy
alias :roles :project_roles
after_create :create_cal_for_project, :make_project_owner
def create_calendar_for_project
self.calendars.create(:name => "default")
end
def make_project_owner
#Make owner of project when created
self.roles.create(:user => User.curr_user, :name => 'O')
end
项目角色.rb
belongs_to :project
belongs_to :user
project_roles 表列是 user_id、project_id、name
我遇到以下错误很难，请提出建议。
谢谢。
→ rails c
> Loading development environment (Rails 3.0.3)
ruby-1.9.2-p0> User.curr_user = User.first
=> #<User id: 1, username: "tispratik", login_email: "tispratik@gmail.com", > is_email_verified: nil, crypted_password: "deed6fa27ffefa57e63592a9b59295abf2660447cf281f34857...", password_salt: "YsD2nLte3pZy1FZ78GD", persistence_token: "84e44908be77b2dc1e41f8dfeacf9ef20c30050ff0c53854e0d...", single_access_token: "cp1bqVSheDh7vl9J48V", perishable_token: "6pGPzdw48nJnJAHsIZQW", last_login_ip: nil, last_login_at: nil, created_at: "2010-11-23 06:00:09", updated_at: "2010-11-23 06:00:09">
ruby-1.9.2-p0> p = Project.create(:name => "ad", :description => "add")
NoMethodError: undefined method `name' for nil:NilClass
from /home/pratik/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.3/lib/active_support/whiny_nil.rb:48:in `method_missing'
from /home/pratik/.rvm/gems/ruby-1.9.2-p0/gems/arel-2.0.4/lib/arel/visitors/to_sql.rb:57:in `block in visit_Arel_Nodes_InsertStatement'
from /home/pratik/.rvm/gems/ruby-1.9.2-p0/gems/arel-2.0.4/lib/arel/visitors/to_sql.rb:56:in `map'
from /home/pratik/.rvm/gems/ruby-1.9.2-p0/gems/arel-2.0.4/lib/arel/visitors/to_sql.rb:56:in `visit_Arel_Nodes_InsertStatement'
from /home/pratik/.rvm/gems/ruby-1.9.2-p0/gems/arel-2.0.4/lib/arel/visitors/visitor.rb:15:in `visit'
from /home/pratik/.rvm/gems/ruby-1.9.2-p0/gems/arel-2.0.4/lib/arel/visitors/visitor.rb:5:in `accept'
from /home/pratik/.rvm/gems/ruby-1.9.2-p0/gems/arel-2.0.4/lib/arel/visitors/to_sql.rb:19:in `block in accept'
from /home/pratik/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.0.3/lib/active_record/connection_adapters/abstract/connection_pool.rb:110:in `with_connection'
from /home/pratik/.rvm/gems/ruby-1.9.2-p0/gems/arel-2.0.4/lib/arel/visitors/to_sql.rb:17:in `accept'
from /home/pratik/.rvm/gems/ruby-1.9.2-p0/gems/arel-2.0.4/lib/arel/tree_manager.rb:19:in `to_sql'
from /home/pratik/.rvm/gems/ruby-1.9.2-p0/gems/arel-2.0.4/lib/arel/select_manager.rb:191:in `insert'
from /home/pratik/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.0.3/lib/active_record/relation.rb:14:in `insert'
from /home/pratik/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.0.3/lib/active_record/persistence.rb:270:in `create'
from /home/pratik/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.0.3/lib/active_record/timestamp.rb:47:in `create'
from /home/pratik/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.0.3/lib/active_record/callbacks.rb:281:in `block in create'
from /home/pratik/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.3/lib/active_support/callbacks.rb:413:in `_run_create_callbacks'
... 30 levels...
from /home/pratik/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.0.3/lib/active_record/attribute_methods/dirty.rb:21:in `save'
from /home/pratik/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.0.3/lib/active_record/transactions.rb:237:in `block (2 levels) in save'
from /home/pratik/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.0.3/lib/active_record/transactions.rb:289:in `block in with_transaction_returning_status'
from /home/pratik/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.0.3/lib/active_record/connection_adapters/abstract/database_statements.rb:139:in `transaction'
from /home/pratik/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.0.3/lib/active_record/transactions.rb:204:in `transaction'
from /home/pratik/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.0.3/lib/active_record/transactions.rb:287:in `with_transaction_returning_status'
from /home/pratik/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.0.3/lib/active_record/transactions.rb:237:in `block in save'
from /home/pratik/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.0.3/lib/active_record/transactions.rb:248:in `rollback_active_record_state!'
from /home/pratik/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.0.3/lib/active_record/transactions.rb:236:in `save'
from /home/pratik/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.0.3/lib/active_record/base.rb:498:in `create'
from (irb):2
from /home/pratik/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.3/lib/rails/commands/console.rb:44:in `start'
from /home/pratik/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.3/lib/rails/commands/console.rb:8:in `start'
from /home/pratik/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.3/lib/rails/commands.rb:23:in `<top (required)>'
from script/rails:6:in `require'
from script/rails:6:in `<main>'
问题出在 make_project_owner 回调中。 create_calendar_for_project 运行良好。
我将 make_project_owner 更改为以下仍然出现相同的问题。
def make_project_owner
#Make owner of project when created
#role.create(:user => User.curr_user, :name => 'O')
ProjectRole.create(:user => User.curr_user, :project => self, :name => "O")
end
我尝试降级 Rails：
rails 3.0.2 -> 有同样的问题
rails 3.0.1 -> 有不同的错误
undefined method `name' for #<Arel::Value:0x00000005795090>
Application Trace | Framework Trace | Full Trace
arel (1.0.1) lib/arel/engines/sql/engine.rb:26:in `block in create'
arel (1.0.1) lib/arel/engines/sql/engine.rb:26:in `each'
arel (1.0.1) lib/arel/engines/sql/engine.rb:26:in `detect'
arel (1.0.1) lib/arel/engines/sql/engine.rb:26:in `create'
arel (1.0.1) lib/arel/algebra/relations/writes.rb:24:in `call'
arel (1.0.1) lib/arel/session.rb:17:in `create'
arel (1.0.1) lib/arel/algebra/relations/relation.rb:159:in `insert'
activerecord (3.0.1) lib/active_record/relation.rb:14:in `insert'
activerecord (3.0.1) lib/active_record/persistence.rb:271:in `create'
activerecord (3.0.1) lib/active_record/timestamp.rb:47:in `create'
activerecord (3.0.1) lib/active_record/callbacks.rb:281:in `block in create'
activesupport (3.0.1) lib/active_support/callbacks.rb:413:in `_run_create_callbacks'
activerecord (3.0.1) lib/active_record/callbacks.rb:281:in `create'
activerecord (3.0.1) lib/active_record/persistence.rb:247:in `create_or_update'
activerecord (3.0.1) lib/active_record/callbacks.rb:277:in `block in create_or_update'
activesupport (3.0.1) lib/active_support/callbacks.rb:423:in `_run_save_callbacks'
activerecord (3.0.1) lib/active_record/callbacks.rb:277:in `create_or_update'
activerecord (3.0.1) lib/active_record/persistence.rb:39:in `save'
activerecord (3.0.1) lib/active_record/validations.rb:43:in `save'
activerecord (3.0.1) lib/active_record/attribute_methods/dirty.rb:21:in `save'
activerecord (3.0.1) lib/active_record/transactions.rb:237:in `block (2 levels) in save'
activerecord (3.0.1) lib/active_record/transactions.rb:289:in `block in with_transaction_returning_status'
activerecord (3.0.1) lib/active_record/connection_adapters/abstract/database_statements.rb:139:in `transaction'
activerecord (3.0.1) lib/active_record/transactions.rb:204:in `transaction'
activerecord (3.0.1) lib/active_record/transactions.rb:287:in `with_transaction_returning_status'
activerecord (3.0.1) lib/active_record/transactions.rb:237:in `block in save'
activerecord (3.0.1) lib/active_record/transactions.rb:248:in `rollback_active_record_state!'
activerecord (3.0.1) lib/active_record/transactions.rb:236:in `save'
activerecord (3.0.1) lib/active_record/base.rb:498:in `create'
app/models/project.rb:70:in `make_project_owner'
activesupport (3.0.1) lib/active_support/callbacks.rb:463:in `_run_create_callbacks'
activerecord (3.0.1) lib/active_record/callbacks.rb:281:in `create'
activerecord (3.0.1) lib/active_record/persistence.rb:247:in `create_or_update'
activerecord (3.0.1) lib/active_record/callbacks.rb:277:in `block in create_or_update'
activesupport (3.0.1) lib/active_support/callbacks.rb:428:in `_run_save_callbacks'
activerecord (3.0.1) lib/active_record/callbacks.rb:277:in `create_or_update'
activerecord (3.0.1) lib/active_record/persistence.rb:39:in `save'
activerecord (3.0.1) lib/active_record/validations.rb:43:in `save'
activerecord (3.0.1) lib/active_record/attribute_methods/dirty.rb:21:in `save'
activerecord (3.0.1) lib/active_record/transactions.rb:237:in `block (2 levels) in save'
activerecord (3.0.1) lib/active_record/transactions.rb:289:in `block in with_transaction_returning_status'
activerecord (3.0.1) lib/active_record/connection_adapters/abstract/database_statements.rb:139:in `transaction'
activerecord (3.0.1) lib/active_record/transactions.rb:204:in `transaction'
activerecord (3.0.1) lib/active_record/transactions.rb:287:in `with_transaction_returning_status'
activerecord (3.0.1) lib/active_record/transactions.rb:237:in `block in save'
activerecord (3.0.1) lib/active_record/transactions.rb:248:in `rollback_active_record_state!'
activerecord (3.0.1) lib/active_record/transactions.rb:236:in `save'
app/controllers/projects_controller.rb:34:in `create'
actionpack (3.0.1) lib/action_controller/metal/implicit_render.rb:4:in `send_action'
actionpack (3.0.1) lib/abstract_controller/base.rb:150:in `process_action'
actionpack (3.0.1) lib/action_controller/metal/rendering.rb:11:in `process_action'
actionpack (3.0.1) lib/abstract_controller/callbacks.rb:18:in `block in process_action'
activesupport (3.0.1) lib/active_support/callbacks.rb:460:in `_run__2176748434120211400__process_action__1031157339911956458__callbacks'
activesupport (3.0.1) lib/active_support/callbacks.rb:409:in `_run_process_action_callbacks'
activesupport (3.0.1) lib/active_support/callbacks.rb:93:in `run_callbacks'
actionpack (3.0.1) lib/abstract_controller/callbacks.rb:17:in `process_action'
actionpack (3.0.1) lib/action_controller/metal/instrumentation.rb:30:in `block in process_action'
activesupport (3.0.1) lib/active_support/notifications.rb:52:in `block in instrument'
activesupport (3.0.1) lib/active_support/notifications/instrumenter.rb:21:in `instrument'
activesupport (3.0.1) lib/active_support/notifications.rb:52:in `instrument'
actionpack (3.0.1) lib/action_controller/metal/instrumentation.rb:29:in `process_action'
actionpack (3.0.1) lib/action_controller/metal/rescue.rb:17:in `process_action'
actionpack (3.0.1) lib/abstract_controller/base.rb:119:in `process'
actionpack (3.0.1) lib/abstract_controller/rendering.rb:40:in `process'
actionpack (3.0.1) lib/action_controller/metal.rb:133:in `dispatch'
actionpack (3.0.1) lib/action_controller/metal/rack_delegation.rb:14:in `dispatch'
actionpack (3.0.1) lib/action_controller/metal.rb:173:in `block in action'
actionpack (3.0.1) lib/action_dispatch/routing/route_set.rb:62:in `call'
actionpack (3.0.1) lib/action_dispatch/routing/route_set.rb:62:in `dispatch'
actionpack (3.0.1) lib/action_dispatch/routing/route_set.rb:27:in `call'
rack-mount (0.6.13) lib/rack/mount/route_set.rb:148:in `block in call'
rack-mount (0.6.13) lib/rack/mount/code_generation.rb:93:in `block in recognize'
rack-mount (0.6.13) lib/rack/mount/code_generation.rb:75:in `optimized_each'
rack-mount (0.6.13) lib/rack/mount/code_generation.rb:92:in `recognize'
rack-mount (0.6.13) lib/rack/mount/route_set.rb:139:in `call'
actionpack (3.0.1) lib/action_dispatch/routing/route_set.rb:492:in `call'
haml (3.0.24) lib/sass/plugin/rack.rb:41:in `call'
actionpack (3.0.1) lib/action_dispatch/middleware/best_standards_support.rb:17:in `call'
actionpack (3.0.1) lib/action_dispatch/middleware/head.rb:14:in `call'
rack (1.2.1) lib/rack/methodoverride.rb:24:in `call'
actionpack (3.0.1) lib/action_dispatch/middleware/params_parser.rb:21:in `call'
actionpack (3.0.1) lib/action_dispatch/middleware/flash.rb:182:in `call'
actionpack (3.0.1) lib/action_dispatch/middleware/session/abstract_store.rb:149:in `call'
actionpack (3.0.1) lib/action_dispatch/middleware/cookies.rb:287:in `call'
activerecord (3.0.1) lib/active_record/query_cache.rb:32:in `block in call'
activerecord (3.0.1) lib/active_record/connection_adapters/abstract/query_cache.rb:28:in `cache'
activerecord (3.0.1) lib/active_record/query_cache.rb:12:in `cache'
activerecord (3.0.1) lib/active_record/query_cache.rb:31:in `call'
activerecord (3.0.1) lib/active_record/connection_adapters/abstract/connection_pool.rb:355:in `call'
actionpack (3.0.1) lib/action_dispatch/middleware/callbacks.rb:46:in `block in call'
activesupport (3.0.1) lib/active_support/callbacks.rb:415:in `_run_call_callbacks'
actionpack (3.0.1) lib/action_dispatch/middleware/callbacks.rb:44:in `call'
rack (1.2.1) lib/rack/sendfile.rb:107:in `call'
actionpack (3.0.1) lib/action_dispatch/middleware/remote_ip.rb:48:in `call'
actionpack (3.0.1) lib/action_dispatch/middleware/show_exceptions.rb:46:in `call'
railties (3.0.1) lib/rails/rack/logger.rb:13:in `call'
rack (1.2.1) lib/rack/runtime.rb:17:in `call'
activesupport (3.0.1) lib/active_support/cache/strategy/local_cache.rb:72:in `call'
rack (1.2.1) lib/rack/lock.rb:11:in `block in call'
<internal:prelude>:10:in `synchronize'
rack (1.2.1) lib/rack/lock.rb:11:in `call'
actionpack (3.0.1) lib/action_dispatch/middleware/static.rb:30:in `call'
railties (3.0.1) lib/rails/application.rb:168:in `call'
railties (3.0.1) lib/rails/application.rb:77:in `method_missing'
railties (3.0.1) lib/rails/rack/log_tailer.rb:14:in `call'
rack (1.2.1) lib/rack/content_length.rb:13:in `call'
rack (1.2.1) lib/rack/handler/webrick.rb:52:in `service'
/home/pratik/.rvm/rubies/ruby-1.9.2-p0/lib/ruby/1.9.1/webrick/httpserver.rb:111:in `service'
/home/pratik/.rvm/rubies/ruby-1.9.2-p0/lib/ruby/1.9.1/webrick/httpserver.rb:70:in `run'
/home/pratik/.rvm/rubies/ruby-1.9.2-p0/lib/ruby/1.9.1/webrick/server.rb:183:in `block in start_thread'
【问题讨论】：
-
请尝试更好地格式化。
-
我无法阅读此乱码错误消息，但很可能是您的
:after_create回调之一导致错误。尝试禁用它们，然后依次禁用它们，这应该会让你更接近找到原因（我认为不匹配的回调名称只是一个编辑错误）。 -
更新了格式，使其看起来更好一些。仍然看起来很漂亮:(另外，我发现问题出在 make_project_owner 回调中，也尝试了上述更改，仍然是同样的错误。
-
需要注意的是，Project 和 ProjectRole 模型都有 :name 字段，不确定是否存在名称冲突。
-
看起来这是 Arel 的现有问题。如果有人调查它，我将不胜感激。谢谢！灯塔票rails.lighthouseapp.com/projects/8994-ruby-on-rails/tickets/…
标签： ruby-on-rails activerecord arel