Make the current Git branch a master branch

Question

I have a repository in Git. I made a branch, then did some changes both to the master and to the branch.

Then, tens of commits later, I realized the branch is in muc

Answer 1

The solutions given here (renaming the branch in 'master') don't insist on the consequences for the remote (GitHub) repo:

• if you hadn't push anything since making that branch, you can rename it and push it without any problem.
• if you had push master on GitHub, you will need to 'git push -f' the new branch: you can no longer push in a fast forward mode.

    -f
    --force

Usually, the command refuses to update a remote ref that is not an ancestor of the local ref used to overwrite it. This flag disables the check. This can cause the remote repository to lose commits; use it with care.

If others have already pulled your repo, they won't be able to pull that new master history without replacing their own master with that new GitHub master branch (or dealing with lots of merges).
There are alternatives to a git push --force for public repos.
Jefromi's answer (merging the right changes back to the original master) is one of them.