Instruction file imported from nhuttruongg/copilot-env (.github/instructions/migration.instructions.md). Copyright stays with the author.

Migration Instructions

Files in migrations/ are 🔴 Critical Path. Extra care required.

Mandatory Rules

• Always auto-flag for @security review when modifying migration files
• Always require @validator regardless of profile
• Every migration MUST be reversible (include down/rollback migration)
• Never delete or modify an already-applied migration — create a new one instead

Safety Checks

• Has a rollback/down migration
• No data loss scenarios (check for DROP, TRUNCATE, column removal)
• No permission escalation (doesn't GRANT unexpected privileges)
• Runs within a transaction (where the DB supports it)
• Handles NULL values when adding NOT NULL columns (provide DEFAULT)
• Large table migrations won't lock the table for extended periods

Testing

• Test both up AND down migrations
• Test with representative data (not just empty tables)
• Verify data integrity after migration round-trip (up → down → up)

Naming

• Use timestamped naming: YYYYMMDDHHMMSS_descriptive_name
• Be descriptive: add_user_email_index not update_users