git rebase: copy instead of moving

Question

My branches are:

o---o  support.2013.16
     \\
      o---o---o---o---o  master
                       \\
                        o---o---o  hotfix/A


        

Answer 1

Git rebase really does copy the original branch to a new one; but because it moves the branch head, it feels like a move rather than a copy. If you used git branch to add an additional branch head to the original branch, you would still have easy access to the original branch after git rebase had made the rebased copy. So in your example

git branch rebased-A hotfix/A
git rebase --onto support.2013.16 master rebased-A

leaves you with

      o---o---o  rebased-A (hotfix/A')
     /
o---o  support.2013.16
     \
      o---o---o---o---o  master
                       \
                        o---o---o  hotfix/A

Answer 2

You could create a new branch:

git checkout -b hotfix/A-support hotfix/A

and rebase it instead. So you will have two branches. Maybe you may decide to drop the branch after merging it into the support branch.

Alternatively, you could rebase the hoftix/A onto the git merge-base support.2013.16 master and then you could easily merge the hotfix/A into both branches. It will give you prettier history, no duplicate commits.