DM-18 Migration Safety Check

April 15, 2026

Version updated for https://github.com/Born14/dm18-migration-check to version v1.0.1.

This action is used across all versions by ? repositories.

Action Type

This is a Node action using Node version 20.

Go to the GitHub Marketplace to find the latest changes.

Action Summary

This GitHub Action, dm18-migration-check, automates the detection of risky SQL migration patterns that add or enforce NOT NULL constraints on columns without default values, which can lead to runtime errors on populated tables. By analyzing pull request changes, reconstructing schema states, and applying the highly precise DM-18 rule (19 true positives, 0 false positives on a public corpus), it generates actionable feedback via comments and ensures migration safety without requiring configuration.

What’s Changed

Patch release focused on one user-visible fix and a set of quality improvements.

Fixed: -- verify: ack DM-18 <reason> comments now suppress the check as documented. Earlier versions parsed the acknowledgement comment but still reported the finding as a failure in the PR comment. If you previously added an ack comment and saw the check fail anyway, it will now pass on re-run.

Also in this release:

The action now emits GitHub Actions warnings when it cannot fully reconstruct the base-branch schema for a group of migrations, so a partial run is visible instead of silent.
Smoke test suite rewritten with bun:test and expanded to cover the ack-suppression contract end-to-end.
README documents that @v1 is the moving major tag and @v1.0.1 is the immutable pin.

No changes to the DM-18 rule itself. The calibration claim (19 true positives, 0 false positives on 761 public Postgres migrations) is unchanged.