IDEA更新失败问题：Couldn't save uncommitted changes 解决方案

今天在更新项目的时候发生错误，调试了很长时间都不能解决。
错误原因：

  Couldn't save uncommitted changes.
  Tried to save uncommitted changes in stash before Update, but failed with an error.
  Couldn't stash file://H:/IdeaProjects/SVSP_0.4: git-write-tree: error building trees
  Cannot save the current index state

经过逐步排查发现是同事上传了多余的文件造成了集体无法更新，解决方案如下：

1. 进入你的项目目录，我的目录是：H:\IdeaProjects\SVSP_0.4,右键选择Git Bash here
2. 输入git status会看到如下信息，注意是Unmerged paths这一段

Unmerged paths:
  (use "git reset HEAD <file>..." to unstage)
  (use "git rm <file>..." to mark resolution)
        both deleted:    .idea/artifacts/SVSP0_4.xml

3. 找到原因，是上传了多余的文件，需要删除both deleted: 后面的 .idea/artifacts/SVSP0_4.xml这个文件
4. 输入 git rm .idea/artifacts/SVSP0_4.xml
5. 再次进入IDEA更新即可解决问题