Title:Leveraging the Crowd for Dependency Management: An Empirical Study on the Dependabot Compatibility Score

Abstract:Dependabot, a popular dependency management tool, includes a compatibility score feature that helps client packages assess the risk of accepting a dependency update by leveraging knowledge from "the crowd". For each dependency update, Dependabot calculates this compatibility score as the proportion of successful updates performed by other client packages that use the same provider package as a dependency. In this paper, we study the efficacy of the compatibility score to help client packages assess the risks involved with accepting a dependency update. We analyze 579,206 pull requests opened by Dependabot to update a dependency, along with 618,045 compatibility score records calculated by Dependabot. We find that a compatibility score cannot be calculated for 83% of the dependency updates due to the lack of data from the crowd. Yet, the vast majority of the scores that can be calculated have a small confidence interval and are based on low-quality data, suggesting that client packages should have additional angles to evaluate the risk of an update and the trustworthiness of the compatibility score. To overcome these limitations, we propose metrics that amplify the input from the crowd and demonstrate the ability of those metrics to predict the acceptance of a successful update by client packages. We also demonstrate that historical update metrics from client packages can be used to provide a more personalized compatibility score. Based on our findings, we argue that, when leveraging the crowd, dependency management bots should include a confidence interval to help calibrate the trust clients can place in the compatibility score, and consider the quality of tests that exercise candidate updates.