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Author: ueshin

python/pyspark/worker.py

@@ -253,6 +253,8 @@ def read_udfs(pickleSer, infile, eval_type):
             "spark.sql.legacy.execution.pandas.groupedMap.assignColumnsByName", "true")\
             .lower() == "true"
 
+        # Scalar Pandas UDF handles struct type arguments as pandas DataFrames instead of
+        # pandas Series. See SPARK-27240.
         df_for_struct = eval_type == PythonEvalType.SQL_SCALAR_PANDAS_UDF
         ser = ArrowStreamPandasUDFSerializer(timezone, safecheck, assign_cols_by_name,
                                              df_for_struct)