org.postgresql.xa.PGXAConnection.rollback(Xid) should return XAER_NOTA

[jmfinelli]

Describe the issue

This issue is a possible misalignment of pgjdbc from the XA specification.

A user of the Narayana community reported that Narayana is invoking rollback even when it is not needed. That report made me realise that, even though it is true that Narayana shouldn't invoke rollback in some cases, pgjdbc is probably not returning the right XAException error code (i.e. XAER_NOTA) from org.postgresql.xa.PGXAConnection.rollback(Xid) when stmt.executeUpdate("ROLLBACK PREPARED '" + s + "'"); fails because of a constraint violation (which happened during prepare). In fact, when the driver returns XA_RBINTEGRITY from this method (which is invoked from this prepare's catch block), I guess that committedOrRolledBack should be also set to true.

Driver Version?
42.6.0

Java Version?
JDK 11

OS Version?
Fedora Linux 38

PostgreSQL Version?
16.2-1

To Reproduce
This is the link to the reproducer of the Narayana community's user that fully demonstrates the issue.

Expected behaviour
org.postgresql.xa.PGXAConnection.rollback(Xid) should return XAER_NOTA when stmt.executeUpdate("ROLLBACK PREPARED '" + s + "'"); fails because there is no transaction with the specified Xid.