Pull Requests Acceptance: A Study Across Programming Languages

Context: The pull-based development is a modern way to support distributed software development, helping to produce high-quality software with increased involvement from the software development community. Objectives: We investigate the effect of source code quality on Pull Request (PR) acceptance in different programming languages, looking at the quality flaws that can be more relevant. Method: We mine software repositories to analyze over 40K PRs from 100 open-source projects in five different programming languages: Python, Java, Kotlin, Haskell, and C/C++. The code quality of the individual PRs was evaluated using static code analysis. Quality flaws were inputted into classification models to predict PRs acceptance and evaluate the fitting. Results: There is a low impact of code quality on PRs acceptance. No major quality flaws can be used to predict reliably PRs acceptance. Conclusion: Source code quality plays a marginal role in accepting PRs in the analyzed projects. Additional factors might impact the acceptance of PRs, such as the reputation and popularity of the submitters.