HHH-9582 means that almost any realistic scenario (certainly for all the projects I've worked on) the enhancer fails. If a class depends on another class, depending upon the order the enhancer visits the classes, the enhancer will incorrectly fail. For example, if a Person entity references an Address entity, then if the enhancer decides to visit the Person first, it will fail to enhance the Person class because it can't resolve the Address class. My initial thinking was that not enhancing a class is bad, but that everything would generally still work (except non-proxy lazy ToOne associations) just slower. But that's also not true - if any class is enhanced, all classes must be enhanced - or a NullPointerException occurs at at org.hibernate.event.internal.DefaultFlushEntityEventListener.isUpdateNecessary(DefaultFlushEntityEventListener.java:238).

HHH-9584 simply means if enhancing fails, you don't know that. The maven build continues along, not knowing something didn't work. This makes issues like HHH-9582 very hard to detect.

That's what I mean by unusable