Spark ANSI mode compatibility: diagnosing implicit cast and column ambiguity risks
Enabling `spark.sql.ansi.enabled` in Apache Spark 3.4 (and the experimental 3.3.x backport) enforces strict SQL standard compliance, rejecting implicit casts and ambiguous column references that legacy code often depends on. The compatibility boundary becomes uncertain when the Spark runtime is paired with a Hive metastore earlier than 3.1.0, because version