During July 2025, this developer enhanced the google/mozc repository by addressing a critical issue in Linux username retrieval. They implemented a defensive fallback mechanism in C++ to handle cases where sysconf(_SC_GETPW_R_SIZE_MAX) is undefined or returns -1, ensuring that getpw-based username lookups remain stable across diverse Linux environments. Drawing on cross-platform development and system programming expertise, the solution introduced a default buffer size to prevent undefined behavior stemming from varying libpwdb implementations. This work improved the reliability and portability of user name resolution within Mozc, demonstrating careful attention to error handling and robust system-level engineering practices.