I built a GitHub Action that catches migration collisions in PRs before they hit main

[saudademjj]

Hey everyone 👋

If you've worked on a team with Drizzle, you've probably hit this:
two developers branch off main, both run drizzle-kit generate,
and both create a migration with the same sequence number.
The second PR to merge silently breaks the migration history —
and you don't find out until deploy or drizzle-kit check fails locally.

I built drizzle-migration-guard to catch this automatically in CI.

What it does

It runs drizzle-kit check on every PR that touches your schema,
migrations, or config — and if there's a collision, it:

1. Posts a sticky PR comment explaining exactly what went wrong
   and a step-by-step fix recipe
2. Classifies the failure — only blocks the PR for actual
   migration collisions, not config typos or unrelated errors
3. Skips itself when the PR has no migration-relevant changes
   (no wasted CI time)

Quick start (2 lines)

- uses: actions/setup-node@v4                                   
  with:                                                                       
    node-version: 20
- run: npm ci                                                                 
- uses: saudademjj/drizzle-migration-guard@v1                                 
  with:                                                                       
    github-token: ${{ github.token }} 

That's it. It auto-detects your drizzle.config.ts — zero extra config
for single-package repos.

A few features worth mentioning

• Monorepo support — set working-directory and/or config globs
  for multi-package setups
• Sticky comment — updates on re-runs instead of spamming new comments
• Granular blocking — fail-on: collision (default), all, or none
• Tracks file renames — renamed schema/migration files are matched
  against both old and new paths
• GitHub Actions summary — readable markdown report in the
  workflow run, even without looking at the PR

Why not just run drizzle-kit check in a script?

You absolutely can. This action adds:

• PR-aware smart filtering (only runs when relevant files changed)
• Failure classification with tailored remediation steps
• A clean PR comment instead of raw CLI output in logs
• Proper monorepo scoping without custom scripting

Links

• GitHub: https://github.com/saudademjj/drizzle-migration-guard
• Marketplace: available on GitHub Marketplace
• MIT licensed, TypeScript, contributions welcome

Would love to hear feedback — especially from teams running Drizzle
in monorepos. If you've been bitten by migration collisions before,
give it a try and let me know how it goes!