In PersistenceRefProcessor the getPersistenceUnitBindingSource method calls PersistenceUnitSearch.resolvePersistenceUnitSupplier to retrieve a  PersistenceUnitMetadata object. It then without checking for null, dereferences that object to get the scoped persistent unit name.

However, resolvePersistenceUnitSupplier through its call to findPersistenceUnitSupplier can return a null value.

When this happens NullPointerException is thrown rather than DeploymentUnitProcessingException as would be expected.