Script to run a shell or command in a clean, temporary copy of a repository.

cleanroom

#!/usr/bin/env bash
# cleanroom: run a command or shell in a clean, temporary copy of a repository.

case "$1" in
-h|-help|--help)
  cat <<'USAGE'
Usage: cleanroom [-h|-help|--help] [CMD...]

Execute a command in a clone of the current repository, made under
a temporary directory.

If no command is given, it runs the current shell in interactive mode.
USAGE
  exit 2
  ;;
esac

quiet() {
  "$@" >/dev/null 2>&1
}

dir="$(pwd)"
top="$(git rev-parse --show-toplevel)"
subdir="${dir#${top}}"
subdir="${subdir#/}"

if ! tempdir="$(mktemp -d)"; then
  exit 1
fi
trap 'rm -rf "${tempdir}"' EXIT

set -e
quiet git clone --reference "${top}" "${top}" "${tempdir}"
quiet cp "${top}/.git/config" "${tempdir}/.git/config"
quiet cd "${tempdir}${subdir:+/$subdir}"
if [ $# -eq 0 ]; then
  "$SHELL" -i
else
  cmd="$1"
  shift
  cmdline="$(printf '%q' "$cmd")"
  if [ $# -gt 0 ]; then
    cmdline+="$(printf ' %q' "$@")"
  fi
  "$SHELL" -ic "$cmdline" cleanroom-script
fi