macOS Homebrew 报错 not in a git directory

错误信息

fatal: not in a git directory
Error: Command failed with exit 128: git

错误诊断

使用brew doctor命令，诊断错误。

brew doctor

输出：

brew doctor
Please note that these warnings are just used to help the Homebrew maintainers
with debugging if you file an issue. If everything you use Homebrew for is
working fine: please don't worry or file an issue; just ignore this. Thanks!

Warning: Homebrew/homebrew-cask was not tapped properly! Run:
  rm -rf "/usr/local/Homebrew/Library/Taps/homebrew/homebrew-cask"
  brew tap homebrew/cask

Warning: Homebrew/homebrew-core was not tapped properly! Run:
  rm -rf "/usr/local/Homebrew/Library/Taps/homebrew/homebrew-core"
  brew tap homebrew/core

Warning: Broken symlinks were found. Remove them with `brew cleanup`:
  /usr/local/share/man/man1/brew-cask.1
  /usr/local/share/zsh/site-functions/_brew_cask

解决方法

使用brew cleanup直接清理无效文件夹。

brew cleanup