if ! command git rev-parse --is-inside-work-tree >/dev/null 2>&1; then
  print "${0}: not a repository work tree: ${PWD}" >&2
  return 1
fi

command git fsck --unreachable 2> /dev/null \
  | grep 'commit' \
  | awk '{print $3}' \
  | command git log \
      --pretty=format:${_git_log_oneline_format} \
      --extended-regexp \
      --grep="${1:-(WIP )?[Oo]n [^:]+:}" \
      --merges \
      --no-walk \
      --stdin