Question

Starting from branch master, to merge a topic branch one just says

git merge topic

If one wants to rebase, however, the commands are

git rebase master topic
git checkout master
git merge topic

The last two lines just fast-forward the master branch to the topic branch, so variation is possible, e.g. I like the following pattern:

git rebase master topic
git rebase topic master

It gets even more complex when the state of the local “topic” branch shall be preserved:

git checkout -b tmp topic
git rebase master
git rebase tmp master
git branch -d tmp

Is there a simple command for that? Something that works as simple as git-merge on the CLI but actually performs a rebase, without moving the topic branch?

Answer 1

There’s no perfect command that does this in one go, but there’s a pretty close second.

Assuming that topic will cleanly fit atop master without conflict, this will work from the master branch:

git cherry-pick master..topic

master..topic is the set of changes in topic but not master, and cherry-picking them in order is effectively a rebase if topic is cleanly on master.

For the two-command perfect-fidelity case (or three to preserve topic), I wouldn’t do two rebases like you have there, I would do a rebase and an update-ref for clarity.