Software Architecture Matters: Challenges and Opportunities for Android Upgrade Conflicts in Practice

Ever since its initial release in 2008, the Android OS has rapidly grown to become the world’s most widely used mobile OS. Mobile vendors extend the Android Open Source Project (AOSP) led by Google to customize their own Android variants. With the AOSP releasing new versions frequently, vendors need to periodically carry out Android upgrades that integrate the latest code changes from AOSP into their Android variants. Both the AOSP and Android variants independently undergo complex modifications. Consequently, Android upgrades often lead to merge conflicts caused by competing changes to the same code line. Vendors have devoted significant effort to understanding and resolving these problems. Despite extensive research on Android upgrades and merge conflicts, there is little understanding of the conflict-related activities performed in Android upgrade practice, and the corresponding challenges faced by practitioners. In this study, we employed a qualitative research methodology involving questionnaires with 120 practitioners and interviews with a leading Android vendor to explore the challenges and improvement opportunities. Our investigation demonstrates that the Android upgrade process is fundamentally an exercise in architectural evolution, necessitating the adoption of architectural thinking rather than relying on mere code-level patches to systematically address upgrade-induced challenges. We have identified challenges at different stages of Android upgrade implementation, including baseline analysis, conflict reason analysis, conflict resolution, and conflict impact analysis. Our findings indicate opportunities for enhancing the Android upgrade practice, particularly in documentation, management, refactoring activities, and team collaboration. Additionally, we outline future research directions from an architectural perspective. We envision that our study can benefit software ecosystems where customized downstream derivatives need to maintain co-evolution with their upstream core.