Refactoring Practices in the Context of Modern Code Review: An Industrial Case Study at Xerox

Modern code review is a common and essential 2 practice employed in both industrial and open-source projects 3 to improve software quality, share knowledge, and ensure con4 formance with coding standards. During code review, developers 5 may inspect and discuss various changes including refactoring 6 activities before merging code changes in the code base. To date, 7 code review has been extensively studied to explore its general 8 challenges, best practices and outcomes, and socio-technical 9 aspects. However, little is known about how refactoring activities 10 are being reviewed, perceived, and practiced. 11 This study aims to reveal insights into how reviewers develop 12 a decision about accepting or rejecting a submitted refactoring 13 request, and what makes such review challenging. We present an 14 industrial case study with 24 professional developers at Xerox. 15 Particularly, we study the motivations, documentation practices, 16 challenges, verification, and implications of refactoring activities 17 during code review. 18 Our study delivers several important findings. Our results 19 report the lack of a proper procedure to follow by developers 20 when documenting their refactorings for review. Our survey 21 with reviewers has also revealed several difficulties related to 22 understanding the refactoring intent and implications on the 23 functional and non-functional aspects of the software. In light of 24 our findings, we recommended a procedure to properly document 25 refactoring activities, as part of our survey feedback