Inconsistencies in Interconnection View between the creation tools proposed and the elements displayed

[pcdavid]

On an Interconnection View diagram, the top-level palette proposes to create some elements like "New Attributes" which can not actually be displayed on the diagram itself. Invoking the tool does create the corresponding semantic element inside the model, but as nothing shows up on the diagram the behavior is confusing for end-users.

Tools that produce semantic elements that are not actually displayed on the diagram in the context the tool is invoked should not be proposed at all in that context.

Capture.video.du.2026-01-09.09-47-50.mp4

[pcdavid]

See org.eclipse.syson.diagram.common.view.services.ViewToolService.toolShouldBeAvailableOnInterconnectionView() for the rules applied in this case.

[pcdavid]

So I've tried to leverage org.eclipse.syson.diagram.common.view.services.ViewFilterSwitch inside toolShouldBeAvailableOnInterconnectionView to remove from the palette creation tools for element types that will not actually be displayed on the diagram. ViewFilterSwitch is used here to filter out exposed elements which should not actually be displayed on a diagram for whatever reason.

However, ViewFilterSwitch requires an actual instance of work on, and when building the palette we only have the type (EClass) of the element. I've tried

var fakeInstance = (Element) EcoreUtil.create(domainClass);
boolean wouldBeDisplayed = new ViewFilterSwitch(ViewDefinitionKind.INTERCONNECTION_VIEW, List.of(fakeInstance), element).doSwitch(fakeInstance);
return toolShouldBeAvailable && wouldBeDisplayed;

But because the fake instance is not actually attached anywhere inside the mode, ViewFilterSwitch returns false for almost all types, and the resulting palette ends up being almost empty.

Manually checking all the creation tools available on the background of an IV, there are actually only 4 which produce semantic elements but do not display anything: New Attribute, New Port, New Port In, New Port Out, New Port Inout. So we will simply filter out AttributeUsage and PortUsage in toolShouldBeAvailableOnInterconnectionView. It's ad hoc, but much simpler than trying a more generic solution for the same result.