我在Windows上. Ruby v.1.9.3p392 / Rails v.3.2.13 – 这是Michael Hart的Ruby on Rails教程第2章中的demo_app项目.
当我发出’rails generate scaffold用户名：string email：string’时,会出现此错误.任何想法如何解决这个问题？
C:\ruby\rails_projects\demo_app>rails generate scaffold User name:string email:s
tring
invoke active_record
C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activerecord-3.2.13/lib/act
ive_record/dynamic_matchers.rb:55:in `method_missing': undefined method `migrati
on_error=' for ActiveRecord::Base:Class (NoMethodError)
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activerecord-3
.2.13/lib/active_record/railtie.rb:66:in `block (3 levels) in <class:Railtie>'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activerecord-3
.2.13/lib/active_record/railtie.rb:65:in `each'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activerecord-3
.2.13/lib/active_record/railtie.rb:65:in `block (2 levels) in <class:Railtie>'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-
3.2.13/lib/active_support/lazy_load_hooks.rb:36:in `instance_eval'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-
3.2.13/lib/active_support/lazy_load_hooks.rb:36:in `execute_hook'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-
3.2.13/lib/active_support/lazy_load_hooks.rb:43:in `block in run_load_hooks'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-
3.2.13/lib/active_support/lazy_load_hooks.rb:42:in `each'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-
3.2.13/lib/active_support/lazy_load_hooks.rb:42:in `run_load_hooks'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activerecord-3
.2.13/lib/active_record/base.rb:720:in `<top (required)>'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/railties-3.2.1
3/lib/rails/generators/named_base.rb:166:in `pluralize_table_names?'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/railties-3.2.1
3/lib/rails/generators/named_base.rb:114:in `table_name'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activerecord-3
.2.13/lib/rails/generators/active_record/model/model_generator.rb:17:in `create_
migration_file'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/thor-0.18.1/li
b/thor/command.rb:27:in `run'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/thor-0.18.1/li
b/thor/invocation.rb:120:in `invoke_command'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/thor-0.18.1/li
b/thor/invocation.rb:127:in `block in invoke_all'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/thor-0.18.1/li
b/thor/invocation.rb:127:in `each'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/thor-0.18.1/li
b/thor/invocation.rb:127:in `map'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/thor-0.18.1/li
b/thor/invocation.rb:127:in `invoke_all'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/thor-0.18.1/li
b/thor/group.rb:233:in `dispatch'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/thor-0.18.1/li
b/thor/invocation.rb:109:in `invoke'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/thor-0.18.1/li
b/thor/group.rb:278:in `block in _invoke_for_class_method'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/thor-0.18.1/li
b/thor/shell.rb:74:in `with_padding'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/thor-0.18.1/li
b/thor/group.rb:267:in `_invoke_for_class_method'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/thor-0.18.1/li
b/thor/group.rb:150:in `_invoke_from_option_orm'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/thor-0.18.1/li
b/thor/command.rb:27:in `run'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/thor-0.18.1/li
b/thor/invocation.rb:120:in `invoke_command'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/thor-0.18.1/li
b/thor/invocation.rb:127:in `block in invoke_all'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/thor-0.18.1/li
b/thor/invocation.rb:127:in `each'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/thor-0.18.1/li
b/thor/invocation.rb:127:in `map'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/thor-0.18.1/li
b/thor/invocation.rb:127:in `invoke_all'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/thor-0.18.1/li
b/thor/group.rb:233:in `dispatch'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/thor-0.18.1/li
b/thor/base.rb:439:in `start'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/railties-3.2.1
3/lib/rails/generators.rb:171:in `invoke'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/railties-3.2.1
3/lib/rails/commands/generate.rb:12:in `<top (required)>'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-
3.2.13/lib/active_support/dependencies.rb:251:in `require'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-
3.2.13/lib/active_support/dependencies.rb:251:in `block in require'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-
3.2.13/lib/active_support/dependencies.rb:236:in `load_dependency'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-
3.2.13/lib/active_support/dependencies.rb:251:in `require'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/railties-3.2.1
3/lib/rails/commands.rb:29:in `<top (required)>'
from bin/rails:4:in `require'
from bin/rails:4:in `<main>'
dynamic_matchers.rb
module ActiveRecord
module DynamicMatchers
def respond_to?(method_id,include_private = false)
if match = DynamicFinderMatch.match(method_id)
return true if all_attributes_exists?(match.attribute_names)
elsif match = DynamicScopeMatch.match(method_id)
return true if all_attributes_exists?(match.attribute_names)
end
super
end
private
# Enables dynamic finders like <tt>User.find_by_user_name(user_name)</tt> and
# <tt>User.scoped_by_user_name(user_name). Refer to Dynamic attribute-based finders
# section at the top of this file for more detailed information.
#
# It's even possible to use all the additional parameters to +find+. For example,the
# full interface for +find_all_by_amount+ is actually <tt>find_all_by_amount(amount,options)</tt>.
#
# Each dynamic finder using <tt>scoped_by_*</tt> is also defined in the class after it
# is first invoked,so that future attempts to use it do not run through method_missing.
def method_missing(method_id,*arguments,&block)
if match = (DynamicFinderMatch.match(method_id) || DynamicScopeMatch.match(method_id))
attribute_names = match.attribute_names
super unless all_attributes_exists?(attribute_names)
if !(match.is_a?(DynamicFinderMatch) && match.instantiator? && arguments.first.is_a?(Hash)) && arguments.size < attribute_names.size
method_trace = "#{__FILE__}:#{__LINE__}:in `#{method_id}'"
backtrace = [method_trace] + caller
raise ArgumentError,"wrong number of arguments (#{arguments.size} for #{attribute_names.size})",backtrace
end
if match.respond_to?(:scope?) && match.scope?
self.class_eval <<-METHOD,__FILE__,__LINE__ + 1
def self.#{method_id}(*args) # def self.scoped_by_user_name_and_password(*args)
attributes = Hash[[:#{attribute_names.join(',:')}].zip(args)] # attributes = Hash[[:user_name,:password].zip(args)]
#
scoped(:conditions => attributes) # scoped(:conditions => attributes)
end # end
METHOD
send(method_id,*arguments)
elsif match.finder?
options = if arguments.length > attribute_names.size
arguments.extract_options!
else
{}
end
relation = options.any? ? scoped(options) : scoped
relation.send :find_by_attributes,match,attribute_names,&block
elsif match.instantiator?
scoped.send :find_or_instantiator_by_attributes,&block
end
else
super
end
end
# Similar in purpose to +expand_hash_conditions_for_aggregates+.
def expand_attribute_names_for_aggregates(attribute_names)
attribute_names.map { |attribute_name|
unless (aggregation = reflect_on_aggregation(attribute_name.to_sym)).nil?
aggregate_mapping(aggregation).map do |field_attr,_|
field_attr.to_sym
end
else
attribute_name.to_sym
end
}.flatten
end
def all_attributes_exists?(attribute_names)
(expand_attribute_names_for_aggregates(attribute_names) -
column_methods_hash.keys).empty?
end
def aggregate_mapping(reflection)
mapping = reflection.options[:mapping] || [reflection.name,reflection.name]
mapping.first.is_a?(Array) ? mapping : [mapping]
end
end
end
解决方法
好吧,所以其他人能够找到这个问题的解决方案,我将在这里分享,以防其他人出现.
显然,我创建的应用程序生成了一个旧的rails版本,即使我的rails版本设置为最近的版本. 3.2.13
因此我的config / application.rb文件与rails 3.2.13版本完全不同.替换application.rb文件后.错误是固定的.
要避免此错误,您可以使用rvm或pik,如果您是Windows用户来控制当前版本.您可以在创建新应用程序’rails 3.2.13 your_app’时指定rails版本,或卸载所有rails版本并只安装您需要的版本：
宝石卸载导轨
– 选择所有版本
gem install rails –version’= 3.2.13′