contrib/json_diff.py

# Copyright 2022 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.

"""Human readable diff two JSON files."""

import difflib
import json
import logging
from pathlib import Path

from chromite.lib import commandline
from chromite.lib import cros_build_lib
from chromite.utils import pformat


def get_parser():
  """Build the argument parser."""
  parser = commandline.ArgumentParser(
      description=__doc__,
      default_log_level='notice')
  parser.add_argument('--format', choices=('unidiff',), default='unidiff',
                      help='Diff output format')
  parser.add_argument('files', nargs=2, help='JSON files to diff')
  return parser


def _parse_arguments(argv):
  """Parse and validate arguments."""
  parser = get_parser()
  opts = parser.parse_args(argv)

  opts.files = [Path(x) for x in opts.files]

  opts.Freeze()
  return opts


def main(argv):
  opts = _parse_arguments(argv)

  file1, file2 = opts.files

  try:
    json1 = json.loads(file1.read_bytes())
    json2 = json.loads(file2.read_bytes())
  except (FileNotFoundError, json.decoder.JSONDecodeError) as e:
    cros_build_lib.Die('%s', e)

  if json1 == json2:
    logging.info('Files are the same')
    return 0

  lines1 = pformat.json(json1).splitlines()
  lines2 = pformat.json(json2).splitlines()

  print('\n'.join(difflib.unified_diff(
      lines1, lines2, fromfile=f'a/{file1}', tofile=f'b/{file2}', lineterm='')))
  return 1