From my post on hibernate-dev list:
Hi all,

ORM 4.2.8.Final breaks the API of EntityKey as it removes tenantId
from the constructor.

Typically, in HSearch, we have the following call:
https://github.com/hibernate/hibernate-search/blob/master/orm/src/main/java/org/hibernate/search/query/hibernate/impl/PersistenceContextObjectsInitializer.java#L74

As 4.2.8.Final removes the tenantId from the EntityKey constructor,
you get a nice:
java.lang.NoSuchMethodError:
org.hibernate.engine.spi.EntityKey.<init>(Ljava/io/Serializable;Lorg/hibernate/persister/entity/EntityPersister;Ljava/lang/String;)V
at org.hibernate.search.query.hibernate.impl.PersistenceContextObjectsInitializer.initializeObjects(PersistenceContextObjectsInitializer.java:73)

From my point of view, the best way to go would be to reintroduce the
constructor in EntityKey, mark it as deprecated and ignore the
tenantId.

I think it's worth a respin and a 4.2.8.SP1.

Thoughts?