Perhaps it could be fixed, so that if the read version is set to 1 and the write version is set to 2, then reading a WAL database is allowed even if the -wal and -shm files are not exist and without creating them, but committing and checkpointing are not allowed unless you first change the read version to 2, and you cannot change the read version from 2 to 1 (while leaving the write version at 2) unless first the database is fully checkpointed and no transactions are active.