A bit of infrastructure to permit stashing a current rebase, permitting performing any number of rebases while working towards the larger rebase.

git-stash-rebase

#!/bin/sh

rebase_head_exists() {
  [ -f "${GIT_ROOT}/REBASE_HEAD${1}" ]
}

rebase_merge_exists() {
  [ -d "${GIT_ROOT}/rebase-merge${1}" ]
}

sanity_check_stash() {
  if rebase_head_exists "${1}" && ! rebase_merge_exists "${1}"; then
    echo "${GIT_ROOT}/REBASE_HEAD${1} exists, but no corresponding ${GIT_ROOT}/rebase-merge${1}! Aborting!" >&2
    exit 1
  elif ! rebase_head_exists "${1}" && rebase_merge_exists "${1}"; then
    echo "${GIT_ROOT}/rebase-merge${1} exists, but no corresponding ${GIT_ROOT}/REBASE_HEAD${1}! Aborting!" >&2
    exit 1
  elif ! rebase_head_exists "" && ! rebase_merge_exists ""; then
    echo "Neither ${GIT_ROOT}/rebase-merge nor ${GIT_ROOT}/REBASE_HEAD exist! Aborting!" >&2
    exit 1
  fi
}

sanity_check_pop() {
  if rebase_head_exists "" || rebase_merge_exists ""; then
    echo "Either ${GIT_ROOT}/REBASE_HEAD or ${GIT_ROOT}/rebase-merge exists, there may be a rebase in progress! Aborting!" >&2
    exit 1
  fi
}

sanity_check_drop() {
  if ! rebase_head_exists "${1}" || ! rebase_merge_exists "${1}"; then
    echo "Either ${GIT_ROOT}/REBASE_HEAD or ${GIT_ROOT}/rebase-merge is missing, it doesn't look like there's a rebase in progress! Aborting!" >&2
    exit 1
  fi
}

do_stash() {
  local found_caches=1

  while rebase_head_exists "$found_caches" && rebase_merge_exists "$found_caches"; do
    found_caches="$((found_caches+1))"
  done
  sanity_check_stash "$found_caches"
  if [ "$found_caches" -gt 1 ]; then
    echo "Found $found_caches previously stashed rebases, continue on, oh brave one!" >&2
  fi
  mv -v "${GIT_ROOT}"/REBASE_HEAD{,"${found_caches}"}
  mv -v "${GIT_ROOT}"/rebase-merge{,"${found_caches}"}
}

do_pop() {
  local found_caches=1

  while rebase_merge_exists "$found_caches"; do
    found_caches="$((found_caches+1))"
  done
  found_caches="$((found_caches-1))"

  sanity_check_pop "$found_caches"

  mv -vf "${GIT_ROOT}"/REBASE_HEAD{"${found_caches}",}
  mv -v "${GIT_ROOT}"/rebase-merge{"${found_caches}",}
}

do_drop() {
  local found_caches=1

  while rebase_head_exists "$found_caches" && rebase_merge_exists "$found_caches"; do
    found_caches="$((found_caches+1))"
  done
  found_caches="$((found_caches-1))"

  sanity_check_drop "$found_caches"

  rm -v "${GIT_ROOT}/REBASE_HEAD${found_caches}"
  rm -rv "${GIT_ROOT}/rebase-merge${found_caches}"
}

do_status() {
  local found_caches=1

  while rebase_head_exists "$found_caches" && rebase_merge_exists "$found_caches"; do
    found_caches="$((found_caches+1))"
  done
  found_caches="$((found_caches-1))"

  if [ "${found_caches}" -ge 1 ]; then
    echo "Current count of stashed rebases is ${found_caches}" >&2
  else
    echo "There are no stashed rebases in progress" >&2
  fi
  exit 0
}

do_help() {
  local name
  name="$(basename "$0")"
  name="${name#git-}"
  echo "Usage: git $name [stash|pop|status]" >&2
  exit 1
}

find_root() {
  git rev-parse --git-dir
}

export GIT_ROOT="$(find_root)"

case "$1" in
  drop)
    do_drop
    ;;
  stash|"")
    do_stash
    ;;
  pop)
    do_pop
    ;;
  status)
    do_status
    ;;
  help|*)
    do_help "$@"
    ;;
esac