git rebase-first-parent

This wrapper around git rebase supports rebasing merge commits, treating them as relative to their first parent (as if running git cherry-pick --mainline=1), whilst preserving all other parents. This is intended to reflect how one normally wishes to rebase a merge from an upstream branch, including subtree merges for vendor imports.

As an example, suppose you have the following commit graph:

A---F---G  upstream
 \
  C---E  local
 /   /
B   D

Running git rebase-first-parent upstream on local (or by passing it as the <branch> argument) will result in the following commit graph:

A---F---G  upstream
         \
          C'--E'  local
         /   /
        B   D

To use this tool, ensure the three scripts present in this repository all appear in your PATH.

The subset of git rebase options supported should behave as their equivalents.

usage: git rebase-first-parent [-i | --interactive] [--onto <newbase>] [<upstream> [<branch>]]

    -h, --help            show the help
    -i, --interactive     let the user edit the list of commits to rebase
    --onto <newbase>      rebase onto given branch instead of upstream