Segregating feature interfaces to support software product line maintenance.

Although software product lines are widely used in practice, their maintenance is challenging. Features as units of behaviour can be heavily scattered across the source code of a product line, hindering modular reasoning. To alleviate this problem, feature interfaces aim at enhancing modular reasoning about features. However, considering all members of a feature interface is often cumbersome, especially due to the large number of members arising in practice. To address this problem, we present an approach to group members of a feature interface based on their mutual dependencies. We argue that often only a subset of all interface members is relevant to a maintenance task. Therefore, we propose a graph representation that is able to capture the collaboration between members and apply a clustering algorithm to it to group highly-related members and segregate non-related members. On a set of ten versions of a real-world product line, we evaluate the effectiveness of our approach, by comparing the two types of feature interfaces (segregated vs. original interfaces) with co-change information from the version-control system. We found a potential reduction of 62% of the interface members to be considered during maintenance. This way, the effort to reason about features can be reduced.