dynamic_matchers.rb:55:in `method_missing'：ActiveRecord::Base:Class 的未定义方法 `migration_error=' (NoMet
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【中文标题】dynamic_matchers.rb:55:in `method_missing\'：ActiveRecord::Base:Class 的未定义方法 `migration_error=\' (NoMethodError)【英文标题】：dynamic_matchers.rb:55:in `method_missing': undefined method `migration_error=' for ActiveRecord::Base:Class (NoMethodError)dynamic_matchers.rb:55:in `method_missing'：ActiveRecord::Base:Class 的未定义方法 `migration_error=' (NoMethodError) 【发布时间】：2013-04-28 04:16:18 【问题描述】：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 User name:string email:string”时出现此错误，知道如何解决这个问题吗？
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, *arguments, &block
elsif match.instantiator?
scoped.send :find_or_instantiator_by_attributes, match, attribute_names, *arguments, &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
【问题讨论】：
【参考方案1】：好的，所以其他人能够找到解决这个问题的方法，我会在这里分享它以防其他人出现。
显然，我正在创建的应用程序正在生成旧的 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。 application.rb 文件被替换后。错误已修复。
为避免此错误，如果您是 Windows 用户，您可以使用 rvm 或 pik 来控制当前版本。您可以在创建新应用“rails 3.2.13 your_app”时指定您的 rails 版本，或者卸载所有 rails 版本并安装您需要的版本：
gem 卸载 rails -选择所有版本
gem install rails --version '= 3.2.13'
【讨论】：
其实应该是'rails new demo_app 3.2.13'来指定一个应用的rails版本，如果需要的话。 对不起，这是正确的命令'rails 3.2.13 new newappname' 嗯，是的，版本规范仍然是错误的。大声笑，但它不需要。 rails 会默认安装最新的 ;)【参考方案2】：感谢您的建议 (+1)，我遇到了同样的问题...
最初使用旧版本的 rails 创建了应用程序，并将其撞到了最新版本 (3.2.13)，这破坏了我的设计内容..
只需将require "rails/all" 添加到config/application.rb 的顶部
【讨论】：
【参考方案3】：我有一个类似的问题是抱怨未定义的方法：'has_many'。在意识到问题之前，我花了一段时间摆弄 ruby 和 rails 版本和 gems……has_many 之前的额外空格！
我从另一个地方复制了旧代码（Evernote，它使用了各种奇怪的格式），但没有意识到空格细节可能会把事情搞砸。删除空格并将它们手动放回修复了问题。
（这并不是对原始问题的真正答案，但我的搜索将我引到这里，也可能将其他人引到这里。）
【讨论】：
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