Development/maintenance/reuse: software evolution in product lines

The evolution tree model is a two-dimensional model that describes how the versions of the artifacts of a software product evolve. The propagation graph is a data structure that can be used for effective control of the evolution of the artifacts of a software product. In this paper we extend the evolution tree model and propagation graph to handle the evolution of a software product line. Software product lines are characterized by large-scale reuse, especially of core assets. We show how a third dimension can be added to the evolution tree model to handle this reuse. In particular, the new model incorporates bidirectional reuse within product lines. That is, the new model can handle the transfer of an artifact from the core assets repository to a specific product (acquiring a core asset) as well as the transfer of a specific asset from a specific product to the core assets repository (mining an existing asset).