Development Considerations and Caveats

This guide helps contributors navigate common development challenges and avoid potential pitfalls when working on GitLab CE and EE.

Consider database and token formatting changes

All deployed code should be designed to support rollbacks, as they are often the fastest way to mitigate incidents. Engineer On Call (EOC) or Incident Manager On Call (IMOC) teams likely do not have full visibility into rollback impacts, so assume any deployment could be reversed.

In addition to following the database migration guide for reversibility, pay special attention to data format changes that affect user-stored data.

When modifying formats for user-stored data (such as authentication tokens, configuration files, or cached values), consider using a phased deployment approach:

1. Phase 1: Deploy validation logic that accepts both old and new formats
2. Phase 2: Deploy issuance logic that creates data in the new format

This approach ensures:

• Older self-managed instances have backward compatibility support
• New format data is only created after validation logic is deployed
• Rollbacks won't create validation failures for newly-issued data
• Users experience no disruption during format transitions