Suppose I have a chain of local git branches, like this:
master branch1 branch2
| | |
o----o----o----A----B----C----D
I pull in an upstream change onto the master branch:
branch1 branch2
| |
A----B----C----D
/
o----o----o----o
|
master
Now I rebase branch1, giving me this:
branch2
|
A----B----C----D
/
o----o----o----o----A'---B'
| |
master branch1
Note that because of rebasing branch1, commits A and B have been rewritten as A' and B'.
Here's my problem: now I want to rebase branch2. The obvious syntax is git rebase branch1 branch2
, but that definitely does not work. What I want it to do is just reapply C and D on top of branch1, but instead it tries to reconcile A and A' and it considers them conflicting.
This does work:
git rebase --onto branch1 branch2^^ branch2
This assumes I know that branch2 has exactly 2 commits beyond the previous branch1 ref.
Since git rebase --onto
works, is there a 1-line git command that will rebase branch2 on top of a newly-rebased branch1, in a way that I don't have to know exactly how many commits were part of branch2? (I want to specify some magic ref instead of branch2^^ for the middle argument.)
Or is there some other approach I'm overlooking?
I would be most interested in a solution that scales well to extreme cases, not just two branches - suppose I've got something more like 5 local branches, all chained on one another, and I want to rebase all of them together.
2022: I described last August in "Git interactive rebase: how to move other branches (refs) automatically?" a new rebase option --update-refs
(Git 2.38, Q3 2022):
Automatically force-update any branches that point to commits that are being rebased.
Any branches that are checked out in a worktree are not updated in this way.
branch1 branch2
| |
A----B----C----D
/
o----o----o----o
|
main
git switch branch2
git rebase --update-refs main
branch1 branch2
| |
A'----B'----C'----D'
/
o----o----o----o
|
main
2013: One-line:
git rebase --onto branch1 branch1tmp branch2
That supposes to make a branch1tmp
on branch1
before rebasing branch1
.
git checkout branch1
git branch branch1tmp
git rebase master
git rebase --onto branch1 branch1tmp branch2
That being said, check what ORIG_HEAD
references.
From git rebase man page:
ORIG_HEAD
is set to point at the tip of the branch before the reset.
So check if this would work (and scale better):
git checkout branch1
git rebase master
git rebase --onto branch1 ORIG_HEAD branch2
git rebase --onto branch2 ORIG_HEAD branch3
...