On the Evolution of Code Readability

Code reading is an activity frequently performed by developers. Before modifying code, developers have to read it, especially if it was authored by others. Several studies have been carried out to find insights related to code readability. However, they were mostly conducted on single (static) code snippets, i.e., they did not consider the ever-changing nature of software. In a preliminary study, we observed that refactoring operations performed by developers to improve several nonfunctional aspects of open-source software systems often result in improved code readability. Motivated by such results, in this research, we studied code readability in the context of software evolution. Especially, we aimed at understanding: (i) to what extent software developers are interested in code readability; (ii) how to code readability evolves in complex software systems;(iii) the influence of developers’ personal characteristics on the evolution of code readability. The results achieved indicate that most of the developers we surveyed reported that they consider readability as an important aspect of the source code. Then, by mining several software repositories we observed that readability rarely changes in software evolution. Therefore, files created unreadable rarely become readable, and vice versa. Finally, we noticed that some personal characteristics of developers have an impact on code readability. In particular, developers’ orienting network (related to their attention) positively correlates with code readability.