Worked on the opensearch-project/k-NN repository to address a stability issue in the k-NN module, specifically targeting segment merges involving scalar-quantized vector fields. Tackled a bug where merges would fail if a segment contained no live vectors by implementing a guarded merge path that skips native index building under these conditions. Enhanced reliability by adding unit tests for empty-vector scenarios and improving type safety through explicit use of Java’s FloatVectorValues. Utilized Java, Lucene, and mocking techniques to ensure robust handling of class hierarchies and maintain correctness for subclass wrappers, while also updating documentation to clarify the maintenance process.