learntocloud Write Migration
Treat any migration merged to a shared branch or applied to an environment as immutable; correct it with a new migration. An unmerged migration may be edited when it is known not to have run outside disposable local databases.
Preserve these production-safety rules:
- Drop incompatible check constraints before transforming rows, then recreate and validate them.
- Clean or merge existing duplicates before adding uniqueness.
- Set local lock and statement timeouts.
- Build production indexes concurrently inside
op.get_context().autocommit_block(). - Make upgrades safe for populated databases and write a valid downgrade.
- Keep one Alembic head and follow repository naming/docstring checks.
Inspect adjacent migrations and api/scripts/lint_migration_sql.py for current
conventions. Run the migration-specific checks plus uv run poe check.