Guiding feature model evolution by lifting code-level dependencies

Feature models are a de facto standard for representing the commonalities and variability of product lines and configurable software systems. Requirements-level features are commonly implemented in multiple source code artifacts, resulting in complex dependencies at the code level. As developers add and evolve features frequently, it is challenging to keep feature models consistent with their implementation. This article thus presents an approach combining feature-to-code mappings and code dependency analyses to inform engineers about possible inconsistencies. We focus on code-level changes requiring updates in feature dependencies and constraints. Our approach uses static code analysis and a variation control system to lift complex code-level dependencies to feature models. We present the suggested dependencies to the engineer in two ways: directly as links between features in a feature model and as a heatmap visualizing the dependency changes of all features in a model. We evaluate our approach by analyzing the evolution history of two case study systems: the Pick-and-Place Unit and the KePlast product line of our industry partner KEBA AG. We present results of evaluating the utility (RQ1) and performance (RQ2) of our approach, as well as the quality of the suggestions (RQ3).