Avoid registration of an extra transaction synchronization for Hibern…

…ate ORM

Hibernate ORM can already handle everything we were doing through that
extra synchronization.

Note that without this patch:

1. Hibernate ORM flushes before transaction completion.
2. Then Hibernate ORM closes the connection wrapper.
3. Then Quarkus flushes again in its own synchronization, which
   usually does nothing, but in some cases (when the dirtiness of some
   entities cannot be known, for example when there are mutable
   @converted properties) it will execute the updates again...
   This is problematic in itself, but it will also lead to acquiring a
   new connection wrapper from Agroal, which will not be closed.
4. Then when the commit happens, Agroal notices a connection wrapper was
   not closed and logs a warning.

Signed-off-by: Yoann Rodière <yoann@hibernate.org>

extensions/hibernate-orm/runtime/src/main/java/io/quarkus/hibernate/orm/runtime/boot/FastBootMetadataBuilder.java

@@ -255,6 +255,9 @@ private MergedSettings mergeSettings(PersistenceUnitDescriptor persistenceUnit)
         cfg.putIfAbsent(AvailableSettings.CONNECTION_HANDLING,
                 PhysicalConnectionHandlingMode.DELAYED_ACQUISITION_AND_RELEASE_BEFORE_TRANSACTION_COMPLETION);
 
+        // Auto-close sessions before transaction completion, as they should be when using JTA.
+        cfg.putIfAbsent(AvailableSettings.AUTO_CLOSE_SESSION, "true");
+
         if (readBooleanConfigurationValue(cfg, WRAP_RESULT_SETS)) {
             LOG.warn("Wrapping result sets is not supported. Setting " + WRAP_RESULT_SETS + " to false.");
         }

extensions/hibernate-orm/runtime/src/main/java/io/quarkus/hibernate/orm/runtime/session/TransactionScopedSession.java

@@ -18,7 +18,6 @@
 import javax.persistence.criteria.CriteriaUpdate;
 import javax.persistence.metamodel.Metamodel;
 import javax.transaction.Status;
-import javax.transaction.Synchronization;
 import javax.transaction.TransactionManager;
 import javax.transaction.TransactionSynchronizationRegistry;
 
@@ -86,17 +85,13 @@ SessionResult acquireSession() {
             Session newSession = sessionFactory.openSession();
             newSession.joinTransaction();
             transactionSynchronizationRegistry.putResource(sessionKey, newSession);
-            transactionSynchronizationRegistry.registerInterposedSynchronization(new Synchronization() {
-                @Override
-                public void beforeCompletion() {
-                    newSession.flush();
-                }
-
-                @Override
-                public void afterCompletion(int i) {
-                    newSession.close();
-                }
-            });
+            // No need to flush or close the session upon transaction completion:
+            // Hibernate ORM itself registers a transaction that does just that.
+            // See:
+            // - io.quarkus.hibernate.orm.runtime.boot.FastBootMetadataBuilder.mergeSettings
+            // - org.hibernate.resource.transaction.backend.jta.internal.JtaTransactionCoordinatorImpl.joinJtaTransaction
+            // - org.hibernate.internal.SessionImpl.beforeTransactionCompletion
+            // - org.hibernate.internal.SessionImpl.afterTransactionCompletion
             return new SessionResult(newSession, false, true);
         } else {
             //this will throw an exception if the request scope is not active