Analysing the Impact of Feature Dependency Implementation on Product Line Stability: an Exploratory Study

The evolution of software product lines (SPLs) is particularly challenging. SPL functionalities, usually decomposed into features, naturally depend among them. As the SPL evolves, the implementation of each feature dependency might increasingly affect more code elements. Therefore, as the complexity of feature dependency implementation grows up through code evolution, it is likely to negatively impact on the SPL stability. Stability refers to the amount of changes between SPL releases and it is directly influenced by the complexity of feature dependency implementation. In this context, a number of emerging programming techniques can be used to keep the complexity of feature dependency code under control. Nevertheless, there is a lack of studies analysing the impact of different programming techniques on the stability of feature dependency code in evolving SPLs. This paper presents a first exploratory analysis on the use of programming techniques to implement and evolve feature dependencies. Our analysis was developed in the context of three evolving SPL systems, which are made up of 210 feature dependencies. Our initial findings reveal that two particular types of feature dependency implementation using different programming techniques play a role in the SPL stability.