$wpdb should store the database engine and request this of drop-ins
|Reported by:||nacin||Owned by:||nacin|
If you have a db.php drop-in, MySQL version checks will be ignored. An update will be allowed to go through.
However, once the update is complete, the drop-in's check_database_version() will be run. If the drop-in uses MySQL (good example would be HyperDB or more commonly a database caching layer, such as W3TC), this is definitely not ideal.
We should do $wpdb->engine = 'mysql'; Then, we'd only skip MySQL version checks if db.php exists AND if engine != 'mysql'.
Only thing this would prevent would be a database drop-in that is designed to support MySQL 4. (And even then, it's just prevent auto-updates.) I don't care to support that.