Christian Kästner, Sven Apel, Syed Saif ur Rahman, Marko Rosenmüller, Don S. Batory, Gunter Saake. On the Impact of the Optional Feature Problem: Analysis and Case Studies. In Proceedings of the 13th International Software Product Line Conference (SPLC). SEI, AUG 2009.
A software product-line is a family of related programs that are distinguished in terms of features. A feature implements a stakeholders' requirement. Different program variants specified by distinct feature selections are produced from a common code base. The optional feature problem describes a common mismatch between variability intended in the domain and dependencies in the implementation. When this occurs, some variants that are valid in the domain cannot be produced due to implementation issues. There are many different solutions to the optional feature problem, but they all suffer from drawbacks such as reduced variability, increased development effort, reduced efficiency, or reduced source code quality. In this paper, we examine the impact of the optional feature problem in two case studies in the domain of embedded database systems, and we survey different state-of-the-art solutions and their trade-offs. Our intension is to raise awareness of the problem, to guide developers in selecting an appropriate solution for their product-line project, and to identify opportunities for future research.