How to rebase after squashing commits in the original branch?

Question

I have

A--B--C master
       \\
        D branch0

Then I squash B and C into B\'. How do I rebase

Answer 1

Use the --onto argument to git rebase, which changes the baseline that git replays work on.

git checkout branch0

At this state you should still see C in your git history.

git rebase --onto B' C

This translates to: Take all commits in my current branch since commit C (In your case that's just D) and play back on top of B'

You can also use the optional <branch> argument to do both the checkout and rebase at once:

git rebase --onto B' C branch0

Answer 2

One quick way I can think of is,

git checkout branch0

Note down the sha of the D commit by git log

git checkout master

Now rename the branch0 to branch1

git branch -m branch0 branch1

A--B' master \ D branch1

Now delete branch1

git branch -D branch1

Create a branch0 again as follows. git checkout -b branch0

A--B' - master&branch0 After the above command master and branch0 are same. Only change we need to make in branch0 is get the commit D.

git cherry-pick D

Now branch0 looks as follows

A--B' master \ D branch0