idea提交代码时.gitignore过滤不生效问题

git rm -r --cached .

git add .

git commit -m 'update .gitignore'

如果遇到报错

error: the following file has staged content different from both the
file and the HEAD:
    .idea/caches/build_file_checksums.ser
(use -f to force removal)

那么再加个-f就完事了:
举例:强制删除.idea文件夹下面的所有文件

git rm -r -f --cached .idea/