Can attach link catch events to a task by copy-pasting

[hkupitz]

Describe the bug

It is possible to attach a link event to a task by copy-pasting it, effectively making it a boundary event which is not allowed according to the BPMN specification.

Afterwards it becomes intertwined with the task and can only be detached by using the arrow keys.

Steps to reproduce

1. Place a task on the canvas.
2. Place an intermediate event on the canvas.
3. Make it a link intermediate catch event.
4. Copy it.
5. Paste it.
6. Attach it to the task.

Expected behavior

Link events should not be able to be attached to a task at all.

Environment

• OS: Windows 10
• Camunda Modeler Version: 5.16.0

Additional context

This does not work with [email protected], so it seems to be caused by something Modeler-specific.

[marstamm]

I can reproduce this. Root cause is the rules for attach rules in camunda-bpmn-js, where we do not consider the spec:
https://github.com/camunda/camunda-bpmn-js/blob/847d4345b6380920c5d9e1fe510ffd50350ba70c/lib/camunda-cloud/features/rules/BpmnRules.js#L87-L90

Moving to ready

[philippfromme]

I found the original issue that led to the introduction of the current behavior: zeebe-io/zeebe-modeler#31. In the meantime the rules in bpmn-js have been adjusted as well (bpmn-io/bpmn-js#1041) to allow attaching intermediate catch events and replacing them with boundary events, so there is some duplication here. I think we should remove the custom attach rule from camunda-bpmn-js and adjust the rule in bpmn-js to allow attaching both intermediate catch and throw events.

[nikku]

Fixed upstream via camunda/camunda-bpmn-js#325.