我有一个谜：我的rvm / ruby-1.9.2环境，运行rails 3.1.3，无法运行此命令 rails生成脚手架游戏名称：string difficulty：string
“方法丢失”失败后，我得到以下转储
kenb@stargate:~/development/sudoku$ rails g scaffold Game name:string difficulty:string
invoke active_record
/home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.3/lib/active_record/base.rb:1088:in `method_missing': undefined method `mass_assignment_sanitizer=' for ActiveRecord::Base:Class (NoMethodError)
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.3/lib/active_record/railtie.rb:59:in `block (3 levels) in <class:Railtie>'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.3/lib/active_record/railtie.rb:58:in `each'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.3/lib/active_record/railtie.rb:58:in `block (2 levels) in <class:Railtie>'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/activesupport-3.1.3/lib/active_support/lazy_load_hooks.rb:36:in `instance_eval'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/activesupport-3.1.3/lib/active_support/lazy_load_hooks.rb:36:in `execute_hook'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/activesupport-3.1.3/lib/active_support/lazy_load_hooks.rb:43:in `block in run_load_hooks'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/activesupport-3.1.3/lib/active_support/lazy_load_hooks.rb:42:in `each'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/activesupport-3.1.3/lib/active_support/lazy_load_hooks.rb:42:in `run_load_hooks'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.3/lib/active_record/base.rb:2190:in `<top (required)>'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.1.3/lib/rails/generators/named_base.rb:165:in `pluralize_table_names?'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.1.3/lib/rails/generators/named_base.rb:112:in `table_name'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.3/lib/rails/generators/active_record/model/model_generator.rb:17:in `create_migration_file'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/thor-0.14.6/lib/thor/task.rb:22:in `run'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/thor-0.14.6/lib/thor/invocation.rb:118:in `invoke_task'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/thor-0.14.6/lib/thor/invocation.rb:124:in `block in invoke_all'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/thor-0.14.6/lib/thor/invocation.rb:124:in `each'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/thor-0.14.6/lib/thor/invocation.rb:124:in `map'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/thor-0.14.6/lib/thor/invocation.rb:124:in `invoke_all'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/thor-0.14.6/lib/thor/group.rb:226:in `dispatch'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/thor-0.14.6/lib/thor/invocation.rb:109:in `invoke'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/thor-0.14.6/lib/thor/group.rb:269:in `block in _invoke_for_class_method'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/thor-0.14.6/lib/thor/shell.rb:74:in `with_padding'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/thor-0.14.6/lib/thor/group.rb:258:in `_invoke_for_class_method'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/thor-0.14.6/lib/thor/group.rb:150:in `_invoke_from_option_orm'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/thor-0.14.6/lib/thor/task.rb:22:in `run'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/thor-0.14.6/lib/thor/invocation.rb:118:in `invoke_task'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/thor-0.14.6/lib/thor/invocation.rb:124:in `block in invoke_all'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/thor-0.14.6/lib/thor/invocation.rb:124:in `each'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/thor-0.14.6/lib/thor/invocation.rb:124:in `map'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/thor-0.14.6/lib/thor/invocation.rb:124:in `invoke_all'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/thor-0.14.6/lib/thor/group.rb:226:in `dispatch'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/thor-0.14.6/lib/thor/base.rb:389:in `start'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.1.3/lib/rails/generators.rb:168:in `invoke'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.1.3/lib/rails/commands/generate.rb:12:in `<top (required)>'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/activesupport-3.1.3/lib/active_support/dependencies.rb:240:in `require'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/activesupport-3.1.3/lib/active_support/dependencies.rb:240:in `block in require'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/activesupport-3.1.3/lib/active_support/dependencies.rb:223:in `block in load_dependency'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/activesupport-3.1.3/lib/active_support/dependencies.rb:640:in `new_constants_in'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/activesupport-3.1.3/lib/active_support/dependencies.rb:223:in `load_dependency'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/activesupport-3.1.3/lib/active_support/dependencies.rb:240:in `require'
from /home/kenb/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.1.3/lib/rails/commands.rb:28:in `<top (required)>'
from script/rails:6:in `require'
from script/rails:6:in `<main>'
我已经删除了rvm和所有依赖的gem，重新安装rvm，ruby-1.9.2，然后在我的app文件夹中运行'bundle install'。一切顺利。然后，我在generate命令上失败了。
答案 0 :(得分：1)
根据http://apidock.com/rails/ActiveModel/MassAssignmentSecurity/ClassMethods/mass_assignment_sanitizer%3D mass_assignment_sanitizer是在rails 3.2中引入的，而你使用的是3.1.3。你没有用rails 3.2生成项目吗？