临时解决 Ruby2.3 上 CocoaPods 出错问题

前段时间 Ruby 发布了 2.3 ，手贱就直接升级了一下，结果 gem 全部都要重装，但是这并不是最坑的。最麻烦的是安装完 cocoapods 之后，pod install 和 pod update，都会报错 NoMethodError - undefined method 'to_ary'，这个可是出大问题。

报错堆栈如下：

NoMethodError - undefined method `to_ary' for #<Pod::Specification name="ReactiveCocoa">
Did you mean?  to_query
/usr/local/lib/ruby/gems/2.3.0/gems/cocoapods-0.39.0/lib/cocoapods/resolver/lazy_specification.rb:14:in `method_missing'
/usr/local/lib/ruby/gems/2.3.0/gems/cocoapods-0.39.0/lib/cocoapods/resolver.rb:64:in `flatten'
/usr/local/lib/ruby/gems/2.3.0/gems/cocoapods-0.39.0/lib/cocoapods/resolver.rb:64:in `block in resolve'
/usr/local/lib/ruby/gems/2.3.0/gems/cocoapods-0.39.0/lib/cocoapods/resolver.rb:63:in `tap'
/usr/local/lib/ruby/gems/2.3.0/gems/cocoapods-0.39.0/lib/cocoapods/resolver.rb:63:in `resolve'
/usr/local/lib/ruby/gems/2.3.0/gems/cocoapods-0.39.0/lib/cocoapods/installer/analyzer.rb:539:in `block in resolve_dependencies'
/usr/local/lib/ruby/gems/2.3.0/gems/cocoapods-0.39.0/lib/cocoapods/user_interface.rb:59:in `section'
/usr/local/lib/ruby/gems/2.3.0/gems/cocoapods-0.39.0/lib/cocoapods/installer/analyzer.rb:537:in `resolve_dependencies'
/usr/local/lib/ruby/gems/2.3.0/gems/cocoapods-0.39.0/lib/cocoapods/installer/analyzer.rb:70:in `analyze'
/usr/local/lib/ruby/gems/2.3.0/gems/cocoapods-0.39.0/lib/cocoapods/installer.rb:213:in `analyze'
/usr/local/lib/ruby/gems/2.3.0/gems/cocoapods-0.39.0/lib/cocoapods/installer.rb:136:in `block in resolve_dependencies'
/usr/local/lib/ruby/gems/2.3.0/gems/cocoapods-0.39.0/lib/cocoapods/user_interface.rb:59:in `section'
/usr/local/lib/ruby/gems/2.3.0/gems/cocoapods-0.39.0/lib/cocoapods/installer.rb:135:in `resolve_dependencies'
/usr/local/lib/ruby/gems/2.3.0/gems/cocoapods-0.39.0/lib/cocoapods/installer.rb:105:in `install!'
/usr/local/lib/ruby/gems/2.3.0/gems/cocoapods-0.39.0/lib/cocoapods/command/project.rb:71:in `run_install_with_update'
/usr/local/lib/ruby/gems/2.3.0/gems/cocoapods-0.39.0/lib/cocoapods/command/project.rb:101:in `run'
/usr/local/lib/ruby/gems/2.3.0/gems/claide-0.9.1/lib/claide/command.rb:312:in `run'
/usr/local/lib/ruby/gems/2.3.0/gems/cocoapods-0.39.0/lib/cocoapods/command.rb:47:in `run'
/usr/local/lib/ruby/gems/2.3.0/gems/cocoapods-0.39.0/bin/pod:44:in `<top (required)>'
/usr/local/bin/pod:23:in `load'
/usr/local/bin/pod:23:in `<main>'

搜索一下发现这个问题已经很多人提上了issue（issues#4345）而且在作者回复说在master上已经解决，但是还没正式发布。

没办法，又不想降级回 2.2，研究了一下修复方案[Resolver] Fix resolution on Ruby 2.3，其实就是加了一个方法，决定手动改本地的文件。

使用 vim 或者你熟悉的编辑工具打开 lazy_specification.rb

vim /usr/local/lib/ruby/gems/2.3.0/gems/cocoapods-0.39.0/lib/cocoapods/resolver/lazy_specification.rb

在第16行也就是 subspec_by_name 的方法上面加入下面代码：

def respond_to_missing?(method, include_all = false)
  specification.respond_to?(method, include_all)
end

这样就搞定了！！！

原文链接：https://blog.yourtion.com/temporary-fix-cocoapod-error-on-ruby-23.html