Worked on the xupefei/spark repository to address a critical issue in Spark SQL’s handling of commutative expressions. Focused on stabilizing the gatherCommutative method, the developer identified and fixed a bug that caused incorrect output ordering, which could lead to unreliable query results. By restoring the intended order of commutative expressions, the change improved the correctness and reliability of Spark SQL queries. The solution was implemented in Scala, leveraging skills in bug fixing, data processing, and software testing. This targeted fix reduced the risk of regressions and helped maintain user trust in the accuracy of Spark SQL’s query behavior.