Towards Trace-Based Synchronization of Variability Annotations in Evolving Model-Driven Product Lines

Annotative model-driven product lines allow to derive individual variants from a multi-variant model by exploiting annotations. Those declare the presence of each model element in a specific set of variants via a logical expression over features and may change during evolution. This provokes the risk of introducing conflicts causing logically cohesive elements of different models to appear in diverging sets of variants, which threatens the consistency of the product line. Existing work on propagating annotations across models employs the comparatively simple strategy of either overwriting or manually protecting any changed annotation in the target model but does not consider a backward propagation nor any form of synchronization. Therefore, we contribute a sophisticated method for synchronizing annotations which detects corresponding elements based on model transformation traces and resolves conflicting annotations by preserving syntactically different but semantically equal annotations according to the feature model. We demonstrate challenges and our solution method in a scenario of synchronizing two corresponding evolving multi-variant models.