ReactNative iOS执行pod install报错：找不到rexml gem依赖

问题描述 #

2021款M1 MacBook Pro首次搭建React Native开发环境，运行iOS项目的pod install命令时触发Gem::MissingSpecError，提示找不到满足要求的rexml gem，导致模拟器运行时构建失败。

报错日志 #

`rescue in block in activate_dependencies': Could not find 'rexml' (>= 0) among 117 total gem(s) (Gem::MissingSpecError)
Checked in 'GEM_PATH=/Users/craigsau/.rvm/gems/ruby-2.7.5:/Users/craigsau/.rvm/rubies/ruby-2.7.5/lib/ruby/gems/2.7.0:/opt/homebrew/Cellar/cocoapods/1.11.3/libexec' at: /opt/homebrew/Cellar/cocoapods/1.11.3/libexec/specifications/CFPropertyList-3.0.5.gemspec, execute `gem env` for more information
    from /opt/homebrew/Cellar/ruby/3.1.2_1/lib/ruby/3.1.0/rubygems/specification.rb:1398:in `block in activate_dependencies'
    from /opt/homebrew/Cellar/ruby/3.1.2_1/lib/ruby/3.1.0/rubygems/specification.rb:1387:in `each'
    from /opt/homebrew/Cellar/ruby/3.1.2_1/lib/ruby/3.1.0/rubygems/specification.rb:1387:in `activate_dependencies'
    from /opt/homebrew/Cellar/ruby/3.1.2_1/lib/ruby/3.1.0/rubygems/specification.rb:1369:in `activate'
    from /opt/homebrew/Cellar/ruby/3.1.2_1/lib/ruby/3.1.0/rubygems/specification.rb:1405:in `block in activate_dependencies'
    from /opt/homebrew/Cellar/ruby/3.1.2_1/lib/ruby/3.1.0/rubygems/specification.rb:1387:in `each'
    from /opt/homebrew/Cellar/ruby/3.1.2_1/lib/ruby/3.1.0/rubygems/specification.rb:1387:in `activate_dependencies'
    from /opt/homebrew/Cellar/ruby/3.1.2_1/lib/ruby/3.1.0/rubygems/specification.rb:1369:in `activate'
    from /opt/homebrew/Cellar/ruby/3.1.2_1/lib/ruby/3.1.0/rubygems/specification.rb:1405:in `block in activate_dependencies'
    from /opt/homebrew/Cellar/ruby/3.1.2_1/lib/ruby/3.1.0/rubygems/specification.rb:1387:in `each'
    from /opt/homebrew/Cellar/ruby/3.1.2_1/lib/ruby/3.1.0/rubygems/specification.rb:1387:in `activate_dependencies'
    from /opt/homebrew/Cellar/ruby/3.1.2_1/lib/ruby/3.1.0/rubygems/specification.rb:1369:in `activate'
    from /opt/homebrew/Cellar/ruby/3.1.2_1/lib/ruby/3.1.0/rubygems.rb:286:in `block in activate_bin_path'
    from /opt/homebrew/Cellar/ruby/3.1.2_1/lib/ruby/3.1.0/rubygems.rb:285:in `synchronize'
    from /opt/homebrew/Cellar/ruby/3.1.2_1/lib/ruby/3.1.0/rubygems.rb:285:in `activate_bin_path'
    from /opt/homebrew/Cellar/cocoapods/1.11.3/libexec/bin/pod:25:in `<main>'

Could not find 'rexml' (>= 0) among 117 total gem(s) (Gem::MissingSpecError)
Checked in 'GEM_PATH=/Users/craigsau/.rvm/gems/ruby-2.7.5:/Users/craigsau/.rvm/rubies/ruby-2.7.5/lib/ruby/gems/2.7.0:/opt/homebrew/Cellar/cocoapods/1.11.3/libexec' , execute `gem env` for more information
    from /opt/homebrew/Cellar/ruby/3.1.2_1/lib/ruby/3.1.0/rubygems/specification.rb:1399:in `block in activate_dependencies'
    from /opt/homebrew/Cellar/ruby/3.1.2_1/lib/ruby/3.1.0/rubygems/specification.rb:1387:in `each'
    from /opt/homebrew/Cellar/ruby/3.1.2_1/lib/ruby/3.1.0/rubygems/specification.rb:1387:in `activate_dependencies'
    from /opt/homebrew/Cellar/ruby/3.1.2_1/lib/ruby/3.1.0/rubygems/specification.rb:1369:in `activate'
    from /opt/homebrew/Cellar/ruby/3.1.2_1/lib/ruby/3.1.0/rubygems/specification.rb:1405:in `block in activate_dependencies'
    from /opt/homebrew/Cellar/ruby/3.1.2_1/lib/ruby/3.1.0/rubygems/specification.rb:1387:in `each'
    from /opt/homebrew/Cellar/ruby/3.1.2_1/lib/ruby/3.1.0/rubygems/specification.rb:1387:in `activate_dependencies'
    from /opt/homebrew/Cellar/ruby/3.1.2_1/lib/ruby/3.1.0/rubygems/specification.rb:1369:in `activate'
    from /opt/homebrew/Cellar/ruby/3.1.2_1/lib/ruby/3.1.0/rubygems/specification.rb:1405:in `block in activate_dependencies'
    from /opt/homebrew/Cellar/ruby/3.1.2_1/lib/ruby/3.1.0/rubygems/specification.rb:1387:in `each'
    from /opt/homebrew/Cellar/ruby/3.1.2_1/lib/ruby/3.1.0/rubygems/specification.rb:1387:in `activate_dependencies'
    from /opt/homebrew/Cellar/ruby/3.1.2_1/lib/ruby/3.1.0/rubygems/specification.rb:1369:in `activate'
    from /opt/homebrew/Cellar/ruby/3.1.2_1/lib/ruby/3.1.0/rubygems.rb:286:in `block in activate_bin_path'
    from /opt/homebrew/Cellar/ruby/3.1.2_1/lib/ruby/3.1.0/rubygems.rb:285:in `synchronize'
    from /opt/homebrew/Cellar/ruby/3.1.2_1/lib/ruby/3.1.0/rubygems.rb:285:in `activate_bin_path'
    from /opt/homebrew/Cellar/cocoapods/1.11.3/libexec/bin/pod:25:in `<main>'

已尝试操作 #

• 执行gem install bundler
• 执行gem update --system
  以上操作后重新运行pod install，问题依旧。

解决方向 #

• 直接安装rexml gem：先切换到报错中显示的Ruby版本（ruby-2.7.5），执行rvm use 2.7.5，再运行gem install rexml，之后重新执行pod install。
• 修复Ruby环境冲突：报错中同时出现RVM管理的ruby-2.7.5和Homebrew安装的ruby-3.1.2，存在环境变量冲突。可执行rvm alias create default ruby-2.7.5设置默认Ruby版本，重启终端后再尝试pod install。
• 为CocoaPods独立环境安装rexml：CocoaPods使用Homebrew安装时的独立gem环境（路径为/opt/homebrew/Cellar/cocoapods/1.11.3/libexec），可指定该路径安装：gem install rexml --install-dir /opt/homebrew/Cellar/cocoapods/1.11.3/libexec。
• 重新安装CocoaPods：卸载现有Homebrew版本的CocoaPods，执行brew uninstall cocoapods；切换到ruby-2.7.5后，执行gem install cocoapods重新安装，再运行pod install。

内容的提问来源于stack exchange，提问作者CraigSau