MacBook Pro升级到MacOS Monterey遇到的问题

环境&背景

1. 当前：MacOS High Sierra
2. 更新至：MacOS Monterey
3. 机型：MacBook Pro (13-inch, 2016, Four Thunderbolt 3 Ports)

问题一、git命令无法使用。[xcrun: error: invalid active developer path ]

1. 拉取代码时，发现git命令无法使用，以为是更新系统导致git被删除，使用命令brew install git来安装git，结果提示必须安装git才可以用brew安装（死循环）：

...$ brew install git
/System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require': cannot load such file -- active_support/core_ext/object/blank (LoadError)
	from /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require'
	from /usr/local/Homebrew/Library/Homebrew/global.rb:10:in `<top (required)>'
	from /usr/local/Homebrew/Library/Homebrew/brew.rb:13:in `require_relative'
	from /usr/local/Homebrew/Library/Homebrew/brew.rb:13:in `<main>'
Error: Git must be installed and in your