I committed twice
A was submitted first; then b was submitted. How to invalidate the submission of a?
git revert a # 把commit a里的改动反过来改一遍
Roll back to the one before a and resubmit b
git reset --hard the_commit_id//id可以在你的git中看到
git revert a # 把commit a里的改动反过来改一遍
Roll back to the one before a and resubmit b