[#1514] Hardening of current transaction state

Author: Sanne

hibernate-reactive-core/src/main/java/org/hibernate/reactive/pool/impl/SqlClientConnection.java

@@ -286,8 +286,12 @@ private SqlConnection client() {
 
 	@Override
 	public CompletionStage<Void> beginTransaction() {
+		if ( transaction != null ) {
+			throw new IllegalStateException( "Can't begin a new transaction as an active transaction is already associated to this connection" );
+		}
 		return connection.begin()
 				.onSuccess( tx -> LOG.tracef( "Transaction started: %s", tx ) )
+				.onFailure( v -> LOG.errorf( "Failed to start a transaction: %s", transaction ) )
 				.toCompletionStage()
 				.thenAccept( this::setTransaction );
 	}
@@ -296,22 +300,28 @@ public CompletionStage<Void> beginTransaction() {
 	public CompletionStage<Void> commitTransaction() {
 		return transaction.commit()
 				.onSuccess( v -> LOG.tracef( "Transaction committed: %s", transaction ) )
+				.onFailure( v -> LOG.errorf( "Failed to commit transaction: %s", transaction ) )
 				.toCompletionStage()
 				.whenComplete( this::clearTransaction );
 	}
 
 	@Override
 	public CompletionStage<Void> rollbackTransaction() {
 		return transaction.rollback()
+				.onFailure( v -> LOG.errorf( "Failed to rollback transaction: %s", transaction ) )
 				.onSuccess( v -> LOG.tracef( "Transaction rolled back: %s", transaction ) )
 				.toCompletionStage()
 				.whenComplete( this::clearTransaction );
 	}
 
 	@Override
 	public CompletionStage<Void> close() {
+		if ( transaction != null ) {
+			throw new IllegalStateException( "Connection being closed with a live transaction associated to it" );
+		}
 		return connection.close()
 				.onSuccess( event -> LOG.tracef( "Connection closed: %s", connection ) )
+				.onFailure( v -> LOG.errorf( "Failed to close a connection: %s", connection ) )
 				.toCompletionStage();
 	}
 
@@ -357,6 +367,7 @@ private void setTransaction(Transaction tx) {
 	}
 
 	private void clearTransaction(Void v, Throwable x) {
+		LOG.tracef( "Clearing current transaction instance from connection: %s", transaction );
 		transaction = null;
 	}