How to avoid setting the isDirty flag?

[rsoika]

I have a situation in my GLSP client/server code that I do not understand regarding the isDirty state:

When I move a BPMN element only a little bit (e.g. 1 px) my custom GModelOperationHandler<ChangeBoundsOperation> is called.
In this handler I recognize that the change is not relevant because of a snap-grid size of 5px. So I do not update my source model.
As a result the element snaps back into the origin position. This is all fine.
But for some reason the isDirty flag is set and indicated on the client side. Means the user is forced to save the model even if nothing has changed at all. I wonder why this is happening.
From another discussion around the isDirty flag I understand that the diry state is only updated automatically if I send (& handle) an Operation from the client to the server.

But means this that a operation like the following is forcing the isDrity Flag?

    private void executeOperation(final ChangeBoundsOperation operation) {
        // DO NOTHING
    }

Can I do something in this method to signal the client that the event was not relevant at all?

[rsoika]

Even with a implementation like this I can't avoid setting the isDirty flag:

public class BPMNChangeBoundsOperationHandler extends GModelOperationHandler<ChangeBoundsOperation> {

    @Inject
    protected BPMNGModelState modelState;

    /**
     * Update the bounds for all selected elements in the GModel and also in the
     * BPMNModel.
     */
    @Override
    public Optional<Command> createCommand(ChangeBoundsOperation operation) {

        return commandOf(() -> {
            boolean changesMade = executeChanges(operation);

            // If no changes were made, do nothing (return early)
            if (!changesMade) {
                return; // Early return from the Runnable
            }

            // Otherwise, proceed with the command execution
            // Assuming the commandOf method handles the creation of the Command object
        });
    }

    // update the source model if needed
    private boolean executeChanges(ChangeBoundsOperation operation) {
      ....
      return result;
    }
     ..
 }

[tortmayr]

Hi @rsoika,
thanks for pointing this out.
This seems to be general GLSP bug. The change bounds tool should not trigger an Operation in the first place if the original position of the element has not changed after a move.

I have opened #1477 to track this.

Regarding your reworked implementation. If you do the check for changes inside of the commandOf/execute method its to late. At this point the command is already created and executed. It will be applied to the commandstack anyways and trigger a DirtyState change.
You need to to the check before you create the command:

   */
    @Override
    public Optional<Command> createCommand(ChangeBoundsOperation operation) {
       boolean changesMade = executeChanges(operation);
        if (!changesMade) {
              return Optional.empty();
         }
        return commandOf(() -> {
          // ...
        });
    }

However, I'm afraid that this currently would not work because the ChangeBoundsOperation is part of a CompoundCommand and even if the subcommand is not created the CommpoundCommand will be executed anyways.

We have to look at this and find a generic fix. At the moment there is unfortunately no easy workaround for this.