koala73/worldmonitor · error · Error

cannot resolve origin/main for the deploy-drift comparison;

Error message

cannot resolve origin/main for the deploy-drift comparison; fetch main or pass --head explicitly

What it means

check-railway-deploy-drift compares deployed Railway commits against authorized main. resolveComparisonHead needs origin/main's SHA; when the git lookup of origin/main fails and no explicit --head was given (or a refresh of main was requested), it throws instead of returning originMainSha: null — because null would downstream read as 'no commits on authorized main' and falsely block the whole fleet with a message blaming the deployment source.

Solutions

Run `git fetch origin main` (or `git fetch --unshallow` in shallow clones) and re-run the check
Pass an explicit `--head <sha-or-ref>` so the comparison does not need to resolve origin/main
Verify the remote default branch name matches what the script expects (origin/main) and update remote/branch or script config accordingly
Check network/remote access if fetch itself is failing

Example fix

// before
node scripts/check-railway-deploy-drift.mjs
// after
git fetch origin main && node scripts/check-railway-deploy-drift.mjs --head origin/main

Defensive patterns

Strategy: try-catch

Validate before calling

try {
  execSync('git rev-parse origin/main', { stdio: 'ignore' });
} catch {
  throw new Error('origin/main unresolvable — run git fetch origin main or pass --head');
}

Try / catch

try {
  await runDriftCheck({ head });
} catch (e) {
  if (e.message.includes('cannot resolve origin/main')) {
    execSync('git fetch origin main', { stdio: 'inherit' });
    await runDriftCheck({ head: 'origin/main' });
  } else throw e;
}

Prevention

Run `git fetch origin main` before deploy-drift checks (or use --unshallow clones in CI)
Always pass an explicit --head in refresh/automation contexts
Confirm the remote default branch name matches origin/main
Keep network access to the git remote in CI jobs

When it happens

Trigger: Running the drift check (without --head, or with main refresh) in a shallow clone, fresh clone without `git fetch origin`, a repo whose remote branch is not named main, or offline / remote-fetch failure so origin/main ref cannot be resolved.

Common situations: CI checkout with depth=1 and no origin/main ref; developer forgot `git fetch origin` after cloning; remote renamed default branch to master/trunk; network/firewall blocking git fetch.

Understand the failure class

Background: "git command failed": what it means when a tool shells out to git and git exits non-zero — this error's family across 21 libraries.

Related errors

AI-assisted analysis of koala73/worldmonitor@7d06c8633d (2026-09-15). Data as JSON: /api/errors/04b822c0839f06ca. Report an issue: GitHub.

Appendix: source

Thrown at scripts/check-railway-deploy-drift.mjs:775

  if (explicit === null || refreshMain) {
    git([
      'fetch',
      '--quiet',
      'origin',
      '+refs/heads/main:refs/remotes/origin/main',
    ]);
  }
  let originMainSha = null;
  try {
    originMainSha = git(['rev-parse', '--verify', '--end-of-options', 'origin/main^{commit}']);
  } catch (error) {
    // Symmetric with the fetch condition above. A refresh call always passes an
    // explicit --head, so keying this on `explicit === null` alone would swallow
    // the failure and hand back originMainSha: null — which reads downstream as
    // "no commit is on authorized main" and blocks the whole fleet with a detail
    // string blaming the deployment source rather than this resolution failure.
    if (explicit === null || refreshMain) {
      throw new Error(
        'cannot resolve origin/main for the deploy-drift comparison; fetch main or pass --head explicitly',
        { cause: error },
      );
    }
  }

  let headSha = originMainSha;
  let headSource = 'origin/main';
  if (explicit !== null) {
    headSource = '--head';
    try {
      headSha = git(['rev-parse', '--verify', '--end-of-options', `${explicit}^{commit}`]);
    } catch (error) {
      throw new Error(`cannot resolve --head ${explicit} to a commit`, { cause: error });
    }
  }

  return {

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