feat(copy-paste): copy error, escalation, message and signal references

[philippfromme]

• copy references when copying element
• add referenced root element if it doesn't exist
• do NOT add referenced root element if root element with same ID exists
• works around Copy & paste: I can mutate the copied business object after copying #798

Related to camunda/camunda-modeler#1049.
Related to camunda/camunda-modeler#1463.

[nikku]

What is the status here? Can I review it?

[philippfromme]

@nikku It's ready.

[philippfromme]

One possible improvement would be to remove references to root elements when they're deleted, even though that's not possible at the moment. It would allow us to add the ability to remove root elements to the properties panel without worrying about other elements referencing them.

[philippfromme]

• remove referenced root element once it's not referenced anymore

We decided to not automatically remove root elements.

[nikku]

I user tested it. Works mostly already:

• Copy on existing diagram keeps message ref
• Copy across to a different diagram keeps message ref
• Copy to different diagram with message non-existing => creates message

What does not yet work (maybe this is a separate feature request):

• When changing a throwing message event to a catching message intermediate event => Message ref is dropped. Expected => Message ref remains valid and is copied/moved across. This applies for errors, signals, ... too.

[philippfromme]

@nikku Shall I continue to work on this?

[nikku]

Let's complete this bug fix with the following feature set:

• No automatic cleanup
• Reference elements by ID
• No special handling / keeping of refs on replace (cf. feat(copy-paste): copy error, escalation, message and signal references #1245 (comment)). This is another feature request.

[philippfromme]

@nikku Ready!

[philippfromme]

🎉

[falko]

Great thx!