Worked on the redis/redis repository to enhance the robustness of the PFMERGE command, specifically addressing edge cases where no source keys are provided. Developed and integrated a new callback function to accurately identify and return the destination key, ensuring correct key specification handling and reducing user friction. The technical approach involved C programming within the Redis command framework, leveraging command handling and error handling techniques. Focused unit testing validated the changes, which improved the reliability and maintainability of the command. This work contributed to greater stability and usability for Redis users, particularly in scenarios involving atypical or incomplete command inputs.