An idea for incorporating a topic branch

git-incorporate

#!/bin/bash

gitdir=$(git rev-parse --git-dir)
if [ -z ${gitdir} ] ; then
  exit 1
fi

if [ "$1" == "" ] ; then
  echo Syntax: incorporate branchname
  exit 1
fi

target_branch=$(git rev-parse --symbolic-full-name $1)
if [ "${target_branch:0:11}" != "refs/heads/" ] ; then
  echo $1 is not a branch 1>&2
  exit 1
fi
target_branch_base=${target_branch:11}

current_branch=$(git rev-parse --symbolic-full-name HEAD)

if [ "${current_branch:0:11}" != "refs/heads/" ] ; then
  echo Not on a branch 1>&2
  exit 1
fi
current_branch_base=${current_branch:11}

common_base=$(git merge-base HEAD $1)
if [ -z "${common_base}" ] ; then
  echo No common base 1>&2
  exit 1
fi

if git rebase --onto ${current_branch_base} ${common_base} ${target_branch}  ; then
  git update-ref ${current_branch} HEAD -m "Incorporate $1 into branch"
  git checkout ${current_branch_base}
else
  echo Failed ${target_branch}  ${current_branch}
fi