sync.js

const shell = require('shelljs');
const log4js = require('log4js');
const Octokit = require('@octokit/rest');
const program = require('commander');
const {getJSON} = require('../util');
// shell.config.silent = true;

program // options
  .option('-d, --delete', 'Delete repo when done')
  .parse(process.argv);

const [srcConfigFile, langConfigFile] = program.args;
if (!srcConfigFile) {
  throw new Error('Source config file not provided');
}
if (!langConfigFile) {
  throw new Error('Language config file not provided');
}

const {owner, repository} = getJSON(srcConfigFile);
const {code: langCode, maintainers} = getJSON(langConfigFile);

const logger = log4js.getLogger(langCode);
logger.level = 'info';

const originalUrl = `https://github.com/${owner}/${repository}.git`;

const username = process.env.USER_NAME;
const token = process.env.GITHUB_ACCESS_TOKEN;
const transRepoName = `${langCode}.${repository}`;
const transUrl = `https://${username}:${token}@github.com/${owner}/${transRepoName}.git`;
const defaultBranch = 'main';

function teardownAndExit() {
  if (program.delete) {
    logger.info('Cleaning up repo...');
    shell.cd('..');
    shell.rm('-rf', transRepoName);
  }
  process.exit(0);
}

// Set up
if (shell.cd('repo').code !== 0) {
  shell.mkdir('repo');
  shell.cd('repo');
}

if (shell.cd(transRepoName).code !== 0) {
  logger.info("Can't find translation repo locally. Cloning...");
  shell.exec(`git clone ${transUrl} ${transRepoName}`);
  logger.debug('Finished cloning.');
  shell.cd(transRepoName);
  shell.exec(`git remote add ${repository} ${originalUrl}`);
}

shell.exec(`git config user.name ${process.env.USER_NAME}`);
shell.exec(`git config user.email ${process.env.USER_EMAIL}`);

shell.exec(`git remote add ${repository} ${originalUrl}`);

// Pull from our own origin
shell.exec(`git checkout ${defaultBranch}`);
shell.exec(`git pull origin ${defaultBranch}`);

// Check out a new branch
shell.exec(`git fetch ${repository} ${defaultBranch}`);
const hash = shell.exec(`git rev-parse ${repository}/${defaultBranch}`).stdout;
const shortHash = hash.substr(0, 8);

const syncBranch = `sync-${shortHash}`;

if (shell.exec(`git checkout ${syncBranch}`).code !== 0) {
  shell.exec(`git checkout -b ${syncBranch}`);
}

// Pull from {source}/main
const output = shell.exec(`git pull ${repository} ${defaultBranch}`).stdout;
if (output.includes('Already up to date.')) {
  logger.info(`We are already up to date with ${repository}.`);
  teardownAndExit();
}
const lines = output.split('\n');

// Commit all merge conflicts
const conflictLines = lines.filter(line => line.startsWith('CONFLICT'));
const conflictFiles = conflictLines.map(line =>
  line.substr(line.lastIndexOf(' ') + 1),
);

shell.exec(`git commit -am "merging all conflicts"`);

// If no conflicts, merge directly into main
if (conflictFiles.length === 0) {
  logger.info('No conflicts found. Committing directly to main.');
  shell.exec(`git checkout ${defaultBranch}`);
  shell.exec(`git merge ${syncBranch}`);
  shell.exec(`git push origin ${defaultBranch}`);
  teardownAndExit();
}

logger.warn('conflict files: ', conflictFiles.join('\n'));

// Create a new pull request, listing all conflicting files
shell.exec(`git push --set-upstream origin ${syncBranch}`);

const title = `Sync with ${repository} @ ${shortHash}`;

const conflictsText = `
The following files have conflicts and may need new translations:

  ${conflictFiles
    .map(
      file =>
        ` * [ ] [${file}](/${owner}/${repository}/commits/main/${file})`,
    )
    .join('\n')}

Please fix the conflicts by pushing new commits to this pull request, either by editing the files directly on GitHub or by checking out this branch.
`;

const body = `
This PR was automatically generated.

Merge changes from [reactjs.org](https://github.com/reactjs/reactjs.org/commits/main) at ${shortHash}

${conflictFiles.length > 0 ? conflictsText : 'No conflicts were found.'}

## DO NOT SQUASH MERGE THIS PULL REQUEST!

Doing so will "erase" the commits from main and cause them to show up as conflicts the next time we merge.
`;

// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/random#Getting_a_random_integer_between_two_values
function getRandomInt(min, max) {
  min = Math.ceil(min);
  max = Math.floor(max);
  return Math.floor(Math.random() * (max - min + 1)) + min;
}

function getRandomSubset(array, n) {
  if (array.length <= n) {
    return array;
  }
  const copy = [...array];
  let result = [];
  while (result.length < n) {
    const i = getRandomInt(0, copy.length);
    result = result.concat(copy.splice(i, 1));
  }
  return result;
}

async function createPullRequest() {
  const octokit = new Octokit({
    auth: `token ${token}`,
    previews: ['hellcat-preview'],
  });

  const {
    data: {number},
  } = await octokit.pulls.create({
    owner,
    repo: transRepoName,
    title,
    body,
    head: syncBranch,
    base: defaultBranch,
  });

  await octokit.pulls.createReviewRequest({
    owner,
    repo: transRepoName,
    number,
    reviewers: getRandomSubset(maintainers, 3),
  });

  teardownAndExit();
}

createPullRequest();