Make a new branch the master in git without messing up existing forks

Question

I have a new line of work that I want to become master. It has diverged from master too much to merge or rebase (though I've manually ported the functionality). I realize I can easily do a git branch -D master; git checkout new-master; git checkout -b master git branch -D master; git checkout new-master; git checkout -b master git branch -D master; git checkout new-master; git checkout -b master , but I don't want to screw up any forks.

Ideally, I'd like to introduce a commit that turns the current master into a state where I can apply my changes from my new branch, so that anyone with a fork can just git pull origin master and git things without incident.

Is this possible?

Answer 1

If you just want branch master to refer to a new commit whose contents are identical to branch branch , with the delta between master^ and master being "change everything to match the contents of branch branch ", that's pretty easy:

$ git checkout branch
$ git symbolic-ref HEAD refs/heads/master
$ git status    # you'll see what you're about to commit, here
$ git commit    # make that new commit

Note that the branch history for master will not refer to branch here.

If you want the commit to look like a merge that changes everything to the way branch looks, this seems to do the trick, but I have not tested it well:

$ git checkout master
$ git merge --no-commit -s ours branch  # this sets up the merge
$ git rm -r .                           # this empties it out
$ git checkout branch -- .              # this adds everything from branch
$ git status   # again, just to see what you're about to commit
$ git commit   # and maybe edit the message to note that you took "branch"

Now master^ is what master used to look like and master^2 is the tip of branch .