What can commit metadata tell us about design degradation?

Design degradation has long been assessed by means of structural analyses applied on successive versions of a software system. More recently, repository mining techniques have been developed in order to uncover rich historical information of software projects. In this paper, we leverage such information and propose an approach to assess design degradation that is programming language agnostic and relies almost exclusively on commit metadata. Our approach currently focuses on the assessment of two particular design smells: rigidity and fragility. Rigidity refer to designs that are difficult to change due to ripple effects and fragility refer to designs that tend to break in different areas every time a change is performed. We conducted an evaluation of our approach in the project Apache Maven 1 and the results indicated that our approach is feasible and that the project suffered from increasing fragility.