Container-managed EXTENDED persistence context is always joined with transaction even if UNSYNCHRONIZED

https://github.com/weld/wildfly/blob/master/testsuite/integration/basic/src/test/java/org/jboss/as/test/integration/jpa/transaction/UnsynchronizedSFSB.jav

Change this test to

@PersistenceContext(type = EXTENDED, synchronization = UNSYNCHRONIZED)

and it will break.

Looks like an extended PC is always joined to the transaction and flushed on commit, the unsynchronized mode is ignored. From what I can see this is not specified and indeed would make the whole new UNSYNCHRONIZED feature kind of pointless. It's primary use case is propagation of unflushed/unsynchronized extended PC from a SFSB to other beans while keeping transactions intact.