An exploratory study of code smells in evolving aspect-oriented systems

Although aspect-oriented programming (AOP) aims to improve software maintainability, developers can unwittingly introduce code smells in their programs. A code smell is any symptom in the source code that possibly indicates a deeper maintainability problem. Even though a few code smells for AOP have been reported in the literature, there is no evidence if and how they occur in evolving software projects. There is also little knowledge on their actual impact on maintenance effort, such as required refactorings or corrective changes in later software releases. This paper presents an exploratory analysis of code smells recurrently observed in a set of evolving aspect-oriented systems. We analyzed instances of code smells previously reported in the literature and newly-revealed ones. Our study involved in total 18 releases of 3 evolving aspect-oriented systems from different domains. The outcome of our evaluation suggests that previously-documented AOP smells might not occur as often as claimed. Our analysis also revealed that: (1) newly-discovered code smells might occur more often than well-known ones, and (2) the former ones seemed to be consistently associated with non-trivial refactorings and corrective changes.