PRESUBMIT.sh

#!/bin/bash
# Copyright 2021 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

# Display an error message.
err() {
  printf "ERROR: %b\n" "$*" >&2
}

# Display an error message & exit.
die() {
  err "$@"
  exit 1
}

# Check the commit message to make sure it follows this repo's formatting
# guidelines.
check_message() {
  local commit="${1:-HEAD}"

  # If there's only one file in the commit, make sure the commit message is
  # scoped to it.
  local message files file prefix
  mapfile -d $'\0' files < <(
    git diff-tree --no-commit-id --name-only -z -r "${commit}" |
      grep -zZ '\.md$')
  if [[ ${#files[@]} -eq 1 ]]; then
    file="${files[0]%.md}"
    message="$(git log -1 --format=%s "${commit}")"
    case "${message}" in
    "${file}: "*|"${file##*/}: "*)
      ;;
    *)
      die "Commit messages should be scoped to the doc you're changing:\n" \
        " ${file##*/}: ${message}"
      ;;
    esac
  fi
}

main() {
  if [[ $# -lt 1 ]]; then
    echo "Usage: $0 <action> [args]"
    exit 1
  fi

  local act="$1"
  shift
  case "${act}" in
  message)
    "check_${act}" "$@"
    ;;
  *)
    die "Unknown action: ${act}"
    ;;
  esac
}
main "$@"