Understanding Breaking Changes in the Wild

Libraries assist in accelerating the development of software applications by providing reusable functionalities. Libraries and applications that declare these libraries as dependencies become their clients. However, as libraries evolve, maintaining the dependencies in client projects can be challenging if the new version contains breaking changes. Yet, limited research focuses on analyzing the impact of breaking changes on client projects when updating dependencies in the wild. Hence, we conduct an empirical analysis using Java projects built using Maven to investigate the impact of breaking changes introduced between two library versions. Our dataset included 18,415 Maven artifacts, declaring 142,355 direct dependencies, out of which 71.60% were not up-to-date. We automatically updated these dependencies and discovered that 11.58% of the dependency updates resulted in breaking changes that affected the client, and almost half of them were introduced during a non-major update. We analyzed the changes in the libraries that contributed towards these breaking changes, and our results indicate that changes in transitive dependencies were a significant factor in introducing breaking changes. We further investigated if it was common for clients to use functionalities of transitive dependencies directly without declaring them. This showed that over half of the clients use transitive functionality. Therefore, we analyzed actions suggested to resolve these breaking changes introduced by transitive dependencies under the discussions on open-source platforms, and the frequently suggested action was to exclude the transitive dependency from the project configuration.