Formalizing feature model integrity: a typing system and refactoring approaches for improving software product line design

Feature modeling plays a pivotal role in the development of Software Product Lines (SPL), enabling the systematic representation of common and variant features across a family of products. However, despite its widespread use, there is a lack of formalization in the typing and well-formedness rules for feature models, leading to potential design flaws and inconsistencies. This paper introduces a comprehensive formalization of feature model typing rules and identifies a catalog of ”bad smells” that indicate suboptimal designs in feature models. An automated toolchain is introduced for detecting bad smells and ensuring adherence to defined typing constraints in feature models. Additionally, a set of refactoring techniques is proposed to address detected issues and enhance the overall design of feature models. The work provides a solid foundation for ensuring that feature model transformations, such as refactorings, preserve model integrity, and supports scalable, maintainable, and error-free feature model management in SPLs.