Context: Ownership metrics measure how the workload of software modules is shared among their developers. They have been shown to be accurate indicators of software quality. Objective: Since ownership metrics studies were done only on industrial software projects, we replicated such a study on Java free/libre and open source software (FLOSS) projects. Our goal was to generalize an ``ownership law'' that stated that minor developers should be avoided. Method: We explored the relationship between ownership metrics and fault-proneness on seven FLOSS projects, using publicly available corpora to retrieve the fault-related information. Results: In our corpus, the relationship between ownership metrics and module faults is weak. At best, less than half of projects exhibit a significant correlation, and at worst, no projects at all. Moreover, fault-proneness seems to be much more influenced by module size than by ownership. Conclusion: The results of ownership studies done on closed-source projects do not generalize to FLOSS projects. To understand the reasons for that, we performed an in-depth analysis and found that the lack of correlation between ownership metrics and module faults is due to the distributions of contributions among developers and the presence of ``heroes'' in FLOSS projects.

More information incoming...