git-reorderhist

#!/bin/sh

#/***************************************************************************
# *   Copyright (C) 2020-2025 Daniel Mueller (deso@posteo.net)              *
# *                                                                         *
# *   This program is free software: you can redistribute it and/or modify  *
# *   it under the terms of the GNU General Public License as published by  *
# *   the Free Software Foundation, either version 3 of the License, or     *
# *   (at your option) any later version.                                   *
# *                                                                         *
# *   This program is distributed in the hope that it will be useful,       *
# *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
# *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
# *   GNU General Public License for more details.                          *
# *                                                                         *
# *   You should have received a copy of the GNU General Public License     *
# *   along with this program.  If not, see <http://www.gnu.org/licenses/>. *
# ***************************************************************************/

set -u -o pipefail

if [ ${#} -ne 1 ]; then
  echo "Usage: $(basename ${0}) <sha1>"
  exit 1
fi

file="$(mktemp)"

# Print log in reverse and use stable sort to preserve existing ordering
# for ties. Use Unix time format to not have to deal with time zone
# stuff (hopefully).
git log --reverse --date=unix --format=format:'%ad pick %H %s' ${1}..HEAD \
  | sort --field-separator=' ' --stable --key=1 --numeric-sort \
  | awk '{$1=""; print $0}' > "${file}"
if [ ${?} -ne 0 ]; then
  echo "git log failed"
  rm -f "${file}"
  exit 1
fi

GIT_EDITOR="sed -i '1 i\x false'" git rebase --interactive --keep-empty ${1}
if [ ${?} -eq 0 ]; then
  rm -f "${file}"
fi
mv "${file}" $(git rev-parse --show-toplevel)/.git/rebase-merge/git-rebase-todo
git rebase --edit-todo
git rebase --continue