Looking at the git-rebase man page, I didn't see any diagrams that looked like what I want (except some seem to do the reverse of what I want), and playing around with --onto didn't get me what I wanted either.
Let me see if I can draw a diagram like the ones from the git-rebase man page (the vertical bars to the left are to make Markdown format it correctly):
| o-o-o-o-branch2
| /
| -o-o-A-master-o-branch1-o-o-my_WIP_branch
branch1 is probably not actually important here, but I included it anyway. What I want to do is get this (omitting the 's that that usually accompany the git-rebase man page diagrams):
| o-o-o-o-branch2-o-branch1-o-o-my_WIP_branch
| /
|-o-o-A-master
Basically, I want to put my my_WIP_branch work over the branch2 work without having to deal with merge conflicts involved in the group of commits labeled A. Is there any way to do this other than manually cherry-picking each commit over branch2 (or at least is there maybe an easy way to do that?)? By the way, there will be merge conflicts, so ideally it should be a git command or group of git commands that handle those gracefully (e.g., git rebase handles them gracefully, git am and git apply do not).