So you have a Github fork of a project and you find a problem. You whip up a fix, commit it in a local branch and push it to your fork you Github. Than you issue a pull request to the upstream repo. Life is good.
But… your pull request is ‘rejected’, kind-of, as the fix is applied differently to their branch. Now your GitHub and local repo are history mismatched to the upstream master. Fetching upstream and merging upstream/master produces conflicts ;-(
First, I do not want to lose the commit that I did do. I want to keep the work/history so a ‘simple’ git hard reset to a prior sha is out of the question.
So lets put your changes on a new branch and reset the master branch back to match the upstream.
Move last commit to a new branch
Note: You will lose uncommitted work, stash first if needed!
git branch newbranch git reset --hard HEAD~1 # Go back 1 commit or use SHA git checkout newbranch
Re-sync your Github fork
Now, lets get everything re-sync’d.
git checkout master
Since you already push this branch to your Github fork, you will see the message:
"Your branch is behind 'origin/master' by 1 commit, and can be fast-forwarded."
That contains your fix, but you need to merge in the upstream/master changes.
git fetch upstream git merge upstream/master
And your local master should Fast-forward to match the upstream. All is good, except your repo on Github is not correct as it contains your original commit on the wrong branch.
git push --force
If you want to keep (backup) that new branch to Github than use the following instead:
git push --all --force
Note: You should not be forcing a push if others have already pulled from your repo/fork. That causes bad git mojo and everyone else that pulled your repo will need to be notified that you ‘changed’ history… That is a git fixup story for another day.
Moral of the story:
Create a bugfix branch with your fixes. It should have one commit (rebase if needed) that will fast-forward and issue your pull-request from that branch.