TravisTorrent: Synthesizing Travis CI and GitHub for Full-Stack Research on Continuous Integration
Open-source projects rely on attracting new and retaining old contributors for achieving sustainable success. One may suspect that adopting new development practices like Continuous Integration (CI) should improve the attractiveness of a project. However, little is known about the impact that adoption of CI has on developer attraction and retention. To bridge this gap, we study how the introduction of TRAVIS CI—a popular CI service provider—impacts developer attraction and retention in 217 GITHUB repositories. Surprisingly, we find that heuristics that estimate the developer attraction and retention of a project are higher in the year before adopting TRAVIS CI than they are in the year following TRAVIS CI adoption. Moreover, the results are statistically significant (Wilcoxon signed rank test, α = 0:05), with small but non-negligible effect sizes (Cliff's delta). Although we do not suspect a causal link, our results are worrisome. More work is needed to ascertain the relationship between CI and developer attraction and retention.