Okay, I had a few minutes to play with this. The module’s user permission section would work until MariaDB 10.3.
The cause was due to 10.4 changing the user table to global_priv: “All user accounts, passwords, and global privileges are now stored in the mysql.global_priv table. The mysql.user table still exists and has exactly the same set of columns as before, but it’s now a view that references the mysql.global_priv table. Tools that analyze the mysql.user table should continue to workas before.”
Just some notes for future updates to the module.
Reference: https://mariadb.com/kb/en/authentication-from-mariadb-104/
Submitted an issue for bug tracking.