UML22 — UML 2 Super/Package merge/redefinitions issue - lost association ends

There is a subtle problem with redefinitions resulting from package merge. Property names have to match by name or the merging property has to redefine the merged property, AND the property types have the same name. Otherwise association ends are lost. For example, consider package Communications which is merged into BehaivorStateMachines. Communications has association ownedBehavior:Behavior <--> context:BehavioredClassifier (ignoring multiplicities to keep the text simpler). BehaviorStateMachines has class StateMachine which specializes Behavior, and has association ownedStateMachine:StateMachine

<--> context:BehavioredClassifier. After the merge, merging BehavioredClassifier must contain two properties for ownedBehavior:Behavior and ownedStatemachine:StateMachine. Otherwise the association to the superclass is lost. This is a case where a class ends up redefining one of its own properties, and where ! the redefined and redefining properties both appear in the merged result.

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