git-droplast

#!/bin/bash

set -euo pipefail

if [[ -z "$(git status --porcelain --untracked-files=no --ignore-submodules)" ]]; then
  git reset --hard HEAD~
  exit 0
elif [[ -n "$(git diff --cached)" ]]; then
  echo "error: has staged changes, not going to stash"
  exit 1
fi

trap 'git stash pop' EXIT
git stash
git reset --hard HEAD~