Worked on the valkey-io/valkey repository to address a stability issue in replicated environments by fixing a crash related to the ACL LOAD command on replicas. The solution involved implementing a null check for client users in C, preventing segmentation faults when ACL LOAD was executed on replica primaries without an associated user. This targeted bug fix improved reliability and reduced downtime in multi-node replication setups. Demonstrated a strong understanding of access control lists, replication workflows, and defensive coding practices. Utilized C programming and Tcl scripting to ensure robust handling of edge cases, contributing to more stable and predictable system behavior.