MigrationWithFollowUpInterface

Interface for migrations with follow-up migrations.

Some migrations need to be derived and executed after other migrations have been successfully executed. For example, a migration might need to be derived based on previously migrated data. For such a case, the migration dependency system is not enough since all migrations would still be derived before any one of them has been executed.

Those "follow-up" migrations need to be tagged with the "Follow-up migration" tag (or any tag in the "follow_up_migration_tags" configuration) and thus they won't be derived with the other migrations.

To get those follow-up migrations derived at the right time, the migrations on which they depend must implement this interface and generate them in the generateFollowUpMigrations() method.

When the migrations implementing this interface have been successfully executed, the follow-up migrations will then be derived having access to the now migrated data.