Rename test for single partition join to clarify that repartitioning is required

Author: kosiew

datafusion/core/tests/physical_optimizer/enforce_distribution.rs

@@ -3747,7 +3747,7 @@ fn distribution_satisfaction_superset_hash_matches_sanity_check() -> Result<()>
 }
 
 #[test]
-fn single_partition_join_skips_repartition() -> Result<()> {
+fn single_partition_join_requires_repartition() -> Result<()> {
     let left = parquet_exec();
     let right = parquet_exec();
     let join_on = vec![(

datafusion/physical-optimizer/src/enforce_distribution.rs

@@ -1314,7 +1314,6 @@ pub fn ensure_distribution(
                     child = add_merge_on_top(child);
                 }
                 Distribution::HashPartitioned(_) => {
-                    // See https://github.com/apache/datafusion/issues/18341#issuecomment-3503238325 for background
                     let satisfaction = distribution_satisfaction(
                         &child.plan,
                         &requirement,