A Preliminary Investigation of Self-Admitted Refactorings in Open Source Software (S)

In software development, developers commit code changes to the version control system. In a commit message, the committer may explicitly claim that the commit is a refactoring with the intention of code quality improvement. We defined such a commit as a self-admitted refactoring (SAR). Currently, there is little knowledge about the SAR phenomenon, and the impact of SARs on software projects is not clear. In this work, we performed a preliminary investigation on SARs with an emphasis on their impact on code quality using the assessment of code smells. We used two non-trivial open source software projects as cases and employed the PMD tool to detect code smells. The study results shows that: (1) SARs tend to improve code quality, though a small proportion of SARs introduced new code smells; and (2) projects that contain SARs have different results on frequently affected code smells. Keywords-self-admitted refactoring; code smell; case study; code quality