The Git repository at the following path is in the detached HEAD state

前言：

      在使用git的时候报错：

The Git repository at the following path is in the detached HEAD state：
You can look around, make experimental changes and commit them, but be sure to checkout a branch not to lose your work. Otherwise you risk losing your changes

分析问题：

      是因为当前的分支不明确，也就是切换分支实际是失败了，可能是你输入的名称有误

解决办法：

    重新输入切换分支命令