Combine migrations

This howto assumes we have django-linear-migrations installed, and that we have a migration file max_migration.txt for each app that contains the latest migration for that app.

To combine migrations 0025-0027 in the core app, where the last migration is 0027

1. Roll back migrations to before all the target migrations, e.g. 0024

   ./script/migrate.sh core 0024
   

2. Delete migration files to be combined.

   rm app/core/migrations/00{25,26,27}_*
   

3. Recreate max_migration.txt

   docker-compose exec web python manage.py create_max_migration_files --recreate core
   # the file core/max_migration.txt should now contain "0024_..."
   

4. Generate combined migration file

   ./script/migrate.sh core
   

When to use this

• PRs can have multiple migration files that should be made into a single create migration for merging.

Who should use this

• Developers