Reference Coupling: An exploration of inter-project technical dependencies and their characteristics within large software ecosystems

摘要

Context: Software projects often depend on other projects or are developed in tandem with other projects. Within such software ecosystems, knowledge of cross-project technical dependencies is important for (1) practitioners understanding of the impact of their code change and coordination needs within the ecosystem and (2) researchers in exploring properties of software ecosystems based on these technical dependencies. However, identifying technical dependencies at the ecosystem level can be challenging.Objective: In this paper, we describe Reference Coupling, a new method that uses solely the information in developers online interactions to detect technical dependencies between projects. The method establishes dependencies through user-specified cross-references between projects. We then use the output of this method to explore the properties of large software ecosystems.Method: We validate our method on two datasets - one from open-source projects hosted on GitHub and one commercial dataset of IBM projects. We manually analyze the identified dependencies, categorize them, and compare them to dependencies specified by the development team. We examine the types of projects involved in the identified ecosystems, the structure of the identified ecosystems, and how the ecosystems structure compares with the social behavior of project contributors and owners.Results: We find that our Reference Coupling method often identifies technical dependencies between projects that are untracked by developers. We describe empirical insights about the characteristics of large software ecosystems. We find that most ecosystems are centered around one project and are interconnected with other ecosystems. By exploring the socio-technical alignment within the GitHub ecosystems, we also found that the project owners social behavior aligns well with the technical dependencies within the ecosystem, but the project contributors social behavior does not align with these dependencies.Conclusions: We conclude with a discussion on future research that is enabled by our Reference Coupling method.