An Empirical Study on Downstream Workarounds for Cross-Project Bugs

GitHub has fostered complicated and enormous software ecosystems, in which projects depend on and co-evolve with each other. An error in an upstream project may affect its downstream projects through inter-dependencies, forming crossproject bugs. Though the upstream developers should fix the bugs on their side, proposing a workaround, i.e., a temporary solution in the downstream project is a common practice for the downstream developers. In this study, we empirically investigated the characteristics of downstream workarounds in the scientific Python ecosystem. Combining the statistical comparisons and manual inspection, we have the following three main findings. First, in general, the workarounds and the corresponding upstream fixes are significantly different in code size and code structure. Second, there are three kinds of crossproject bugs that the downstream developers usually work around. Last, four types of common patterns are identified from the investigated workarounds. The findings of this study lead to better understanding of cross-project bugs and the practices of developers in software ecosystems.