Who Gets a Patch Accepted First? Comparing the Contributions of Employees and Volunteers

Although many software companies have recently embraced Open Source Software (OSS) initiatives, volunteers (i.e., developers who contribute to OSS in their spare time) still represent a wealthy workforce that have the potential of driving many non-trivial open source projects. Such volunteers face well-known barriers when attempting to contribute to OSS projects. However, what is still unclear is how the problems that volunteers face transcend to the problems that employees (i.e., developers hired by a software company to work on OSS projects) face. In this paper we aim to investigate the differences on the acceptance of patches submitted by volunteers and employees to company-owned OSS projects. We explore different characteristics of the patches submitted to company-owned OSS project, including: the frequency of acceptance and rejection; the total time to review and process a patch, and; whether the changes proposed follow some contribution best practices. We found that volunteers face 26x more rejections than employees. Volunteers have to wait, on average, 11 days to have a patch processed (employees wait 2 days, on average). 92% of the dormant pull-requests (e.g., pull-requests that take too long to be processed) were submitted by employees. Finally, we observed that the best practices that had the patches are most adherent to is "commit messages need to be written in English".