vercel/utils/update-gatsby-fixtures.js

const path = require('path');
const fs = require('fs');
const { exec } = require('./exec');

const branch = `update/gatsby-fixtures`;

/**
 * invoked by ../.github/workflows/cron-test-and-update-gatsby.yml
 * @param {{ github: ReturnType<import('@actions/github').getOctokit>, context: import('@actions/github').context }} param0 Defined by https://github.com/actions/github-script
 * @returns
 */
module.exports = async ({ github, context }) => {
  exec('git', ['config', '--global', 'user.email', 'infra+release@vercel.com']);
  exec('git', ['config', '--global', 'user.name', 'vercel-release-bot']);
  try {
    // Branch may exist if there's already an existing PR
    exec('git', ['checkout', branch]);
  } catch {
    exec('git', ['checkout', '-b', branch]);
  }

  const fixturePath = path.join(
    '..',
    'packages',
    'static-build',
    'test',
    'fixtures'
  );
  const gatsbyFixtures = [
    'gatsby-v2',
    'gatsby-v3',
    'gatsby-v4-pnpm',
    'gatsby-v4',
    'gatsby-v5-pathPrefix',
    'gatsby-v5',
  ];

  let somethingChanged = false;

  for (const fixture of gatsbyFixtures) {
    const packageJSONPath = path.join(fixturePath, fixture);
    const packageJSON = JSON.parse(fs.readFileSync(packageJSONPath, 'utf-8'));

    const oldVersion = packageJSON.dependencies.gatsby;

    const versions = exec('npm', [
      'view',
      `gatsby@'^${oldVersion}'`,
      'version',
    ]); // [ "gatsby@5.1.2 '5.1.2'", "gatsby@5.2.0 '5.2.0'" ]
    const newVersion = versions.split('\n').pop().split(' ')[1]; // takes the version string from the last result of `versions` i.e. '5.2.0'

    if (oldVersion === newVersion) {
      console.log(
        `gatsby version ${newVersion} did not change for fixture ${fixture}, skipping update.`
      );
      continue;
    }

    somethingChanged = true;

    packageJSON.dependencies.gatsby = newVersion;

    fs.writeFileSync(
      packageJSONPath,
      JSON.stringify(packageJSON, null, 2) + '\n',
      'utf-8'
    );

    // update lockfiles
    if (fixture.includes('pnpm')) {
      exec('pnpm', ['install', '--lockfile-only']);
    } else {
      exec('npm', ['install', '--package-lock-only']);
    }
  }

  if (somethingChanged) {
    exec('git', ['add', '-A']);
    exec('git', ['commit', '-m', branch]);
    exec('git', ['push', 'origin', branch]);

    const { repo, owner } = context.repo;

    const pulls = await github.rest.pulls.list({
      owner,
      repo,
      state: 'open',
      head: branch,
    });

    if (pulls.length === 0) {
      const pr = await github.rest.pulls.create({
        owner,
        repo,
        head: branch,
        base: 'main',
        title: '[tests] Update Gatsby fixture versions',
        body: 'Automatically generated PR to update Gatsby fixture versions in `@vercel/static-build`',
      });

      await github.rest.pulls.requestReviewers({
        owner,
        repo,
        pull_number: pr.data.number,
        reviewers: [
          'Ethan-Arrowood',
          'styfle',
          'TooTallNate',
          'EndangeredMassa',
          'cb1kenobi',
        ],
      });

      await github.rest.issues.addLabels({
        owner,
        repo,
        issue_number: pr.data.number,
        labels: ['area: tests', 'semver: none', 'pr: automerge'],
      });
    }
  }
};