I have the following situation in Git:
A--B--C--D--E--F--G
\--H--I
I want to rebase the branch, but keep the original branch. So I want this:
A--B--C--D--E--F--G
\--H--I \--H'--I'
The reason is that it's possible that my rebased branch will break things. If it does too much, and I can't easily fix it, I want to keep working with the old branch.
This is in a situation where the master branch is actually based on another repository and is a long way behind the original repository. I'm trying to get our (H-I) branch back up to the latest version of the original master branch.
Just create a new branch an work on it.
git checkout your-old-branch
git checkout -b to-be-rebased
git rebase master
and work on to-be-rebased until you have something workable.
So your-old-branch still points to the same exact commit, unaffected.
...and the two first checkout steps can be combined into one (as pointed out by Johnathon) to avoid an unnecessary check out step :
git checkout -b to-be-rebased your-old-branch
Lastly, to be fair to Lasse's comment, it's true that we could have proceeded with cherry-pick to the same effect :
git checkout -b new-branch master
git cherry-pick master..your-old-branch