[#2699] Make sure to close the connection in case of error

I've tested it while working on #2518, but I don't know how to
create an isolated test.

Author: DavideD

hibernate-reactive-core/src/main/java/org/hibernate/reactive/logging/impl/Log.java

@@ -273,6 +273,10 @@ public interface Log extends BasicLogger {
 	@Message(id = 85, value = "Reactive sessions do not support transparent lazy fetching - use Stage.fetch() or Mutiny.fetch() (property '%1$S' of entity '%2$s' was not loaded)")
 	LazyInitializationException lazyFieldInitializationException(String fieldName, String entityName);
 
+	@LogMessage(level = ERROR)
+	@Message(id = 86, value = "Error closing reactive connection")
+	void errorClosingConnection(@Cause Throwable throwable);
+
 	// Same method that exists in CoreMessageLogger
 	@LogMessage(level = WARN)
 	@Message(id = 104, value = "firstResult/maxResults specified with collection fetch; applying in memory!" )
@@ -331,5 +335,4 @@ public interface Log extends BasicLogger {
 			" This is probably due to an operation failing fast due to the transaction being marked for rollback.",
 			id = 520)
 	void jdbcExceptionThrownWithTransactionRolledBack(@Cause JDBCException e);
-
 }

hibernate-reactive-core/src/main/java/org/hibernate/reactive/session/impl/ReactiveSessionImpl.java

@@ -1728,7 +1728,23 @@ public void close() throws HibernateException {
 
 	@Override
 	public CompletionStage<Void> reactiveClose() {
-		super.close();
+		try {
+			super.close();
+			return closeConnection();
+		}
+		catch (RuntimeException e) {
+			return closeConnection()
+					.handle( CompletionStages::handle )
+					.thenCompose( closeConnectionHandler -> {
+						if ( closeConnectionHandler.hasFailed() ) {
+							LOG.errorClosingConnection( closeConnectionHandler.getThrowable() );
+						}
+						return failedFuture( e );
+					} );
+		}
+	}
+
+	private CompletionStage<Void> closeConnection() {
 		return reactiveConnection != null
 				? reactiveConnection.close()
 				: voidFuture();