#!/bin/sh

set -uex

git fetch upstream
branches="$(git branch -r | sed -n 's_^.*upstream/r/__p' | sort -h | sed 's_^_r/_' | tail -n3) develop"

lastbranch=""
for branch in $branches; do
  git checkout "${branch}"
  git merge "upstream/${branch}"
  test "$(git rev-parse "${branch}")" = "$(git rev-parse "upstream/${branch}")"
  if [ -n "${lastbranch}" ]; then
    git merge "upstream/${lastbranch}" -m "Merge ${lastbranch} into ${branch}"
    git push upstream "${branch}"
  fi
  lastbranch="${branch}"
done