Enhancement
Major
Detail
Major
Detail
Bugfix
If you delete the object stored in a reference-valued attribute, accesses to this attribute should subsequently return the value null. However, if the reference is marked with the deletion policy "veto", the access fails with an exception. Since the deletion policy is enforced only in the commit, accesses after the (still transient) deletion of the object and the (failing) commit must be answered normally with null - as if the deletion had been successful.
Test
No test, too complex.