gistfile1.txt

Consider this:

I have developed a feature on a branch (F) that is merged into a staging branch (S) using `--no-ff`.
Meanwhile, the master branch (M) has evolved:

I--------M
 \
  \---S
   \ /
    F

I'd like to rebase S onto M to make sure my changes are still working.
I'd like to keep the merge commit on S to see where features have been merged:

I---M---S
     \ /
      F

What I always get is:

I---M---F

What I've tried:

on branch S: git rebase M
on branch S: git rebase -p M
on branch S: git rebase --onto M M^
on branch S: git rebase -p --onto M M^
on branch M: git cherry-pick -m 1 S

A repo for proof of concept can be found at http://github.com/awendt/git-task