Address comments.

Author: viirya

sql/catalyst/src/main/scala/org/apache/spark/sql/internal/SQLConf.scala

@@ -2064,13 +2064,13 @@ object SQLConf {
       .createWithDefault(true)
 
   val NESTED_PREDICATE_PUSHDOWN_V1_SOURCE_LIST =
-    buildConf("spark.sql.optimizer.nestedPredicatePushdown.v1sourceList")
+    buildConf("spark.sql.optimizer.nestedPredicatePushdown.supportedV1Sources")
       .internal()
       .doc("A comma-separated list of data source short names or fully qualified data source " +
         "implementation class names for which Spark tries to push down predicates for nested " +
-        "columns and or names containing `dots` to data sources. Currently, Parquet implements " +
+        "columns and/or names containing `dots` to data sources. Currently, Parquet implements " +
         "both optimizations while ORC only supports predicates for names containing `dots`. The " +
-        "other data sources don't support this feature yet.")
+        "other data sources don't support this feature yet. So the default value is 'parquet,orc'.")
       .version("3.0.0")
       .stringConf
       .createWithDefault("parquet,orc")
@@ -3099,9 +3099,6 @@ class SQLConf extends Serializable with Logging {
 
   def nestedSchemaPruningEnabled: Boolean = getConf(NESTED_SCHEMA_PRUNING_ENABLED)
 
-  def nestedPredicatePushdownv1SourceList: String =
-    getConf(NESTED_PREDICATE_PUSHDOWN_V1_SOURCE_LIST)
-
   def serializerNestedSchemaPruningEnabled: Boolean =
     getConf(SERIALIZER_NESTED_SCHEMA_PRUNING_ENABLED)
 

sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/DataSourceStrategy.scala

@@ -532,8 +532,7 @@ object DataSourceStrategy {
    * @param translatedFilterToExpr An optional map from leaf node filter expressions to its
    *                               translated [[Filter]]. The map is used for rebuilding
    *                               [[Expression]] from [[Filter]].
-   * @param nestedPredicatePushdownEnabled Whether nested predicate pushdown is enabled. Default is
-   *                                       disabled.
+   * @param nestedPredicatePushdownEnabled Whether nested predicate pushdown is enabled.
    * @return a `Some[Filter]` if the input [[Expression]] is convertible, otherwise a `None`.
    */
   protected[sql] def translateFilterWithMapping(
@@ -572,12 +571,7 @@ object DataSourceStrategy {
           .map(sources.Not)
 
       case other =>
-        val pushableColumn = if (nestedPredicatePushdownEnabled) {
-          PushableColumnAndNestedColumn
-        } else {
-          PushableColumnWithoutNestedColumn
-        }
-        val filter = translateLeafNodeFilter(other, pushableColumn)
+        val filter = translateLeafNodeFilter(other, PushableColumn(nestedPredicatePushdownEnabled))
         if (filter.isDefined && translatedFilterToExpr.isDefined) {
           translatedFilterToExpr.get(filter.get) = predicate
         }
@@ -687,6 +681,16 @@ abstract class PushableColumnBase {
   }
 }
 
+object PushableColumn {
+  def apply(nestedPredicatePushdownEnabled: Boolean): PushableColumnBase = {
+    if (nestedPredicatePushdownEnabled) {
+      PushableColumnAndNestedColumn
+    } else {
+      PushableColumnWithoutNestedColumn
+    }
+  }
+}
+
 object PushableColumnAndNestedColumn extends PushableColumnBase {
   override val nestedPredicatePushdownEnabled = true
 }

sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/DataSourceUtils.scala

@@ -78,9 +78,8 @@ object DataSourceUtils {
     relation match {
       case hs: HadoopFsRelation =>
         val supportedDatasources =
-          SQLConf.get.getConf(SQLConf.NESTED_PREDICATE_PUSHDOWN_V1_SOURCE_LIST)
-            .toLowerCase(Locale.ROOT)
-            .split(",").map(_.trim)
+          Utils.stringToSeq(SQLConf.get.getConf(SQLConf.NESTED_PREDICATE_PUSHDOWN_V1_SOURCE_LIST)
+            .toLowerCase(Locale.ROOT))
         supportedDatasources.contains(hs.toString)
       case _ => false
     }

sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/FileSourceStrategy.scala

@@ -182,7 +182,7 @@ object FileSourceStrategy extends Strategy with Logging {
         DataSourceUtils.supportNestedPredicatePushdown(fsRelation)
       val pushedFilters = dataFilters
         .flatMap(DataSourceStrategy.translateFilter(_, supportNestedPredicatePushdown))
-      logInfo(s"Pushed Filters: " + s"${pushedFilters.mkString(",")}")
+      logInfo(s"Pushed Filters: ${pushedFilters.mkString(",")}")
 
       // Predicates with both partition keys and attributes need to be evaluated after the scan.
       val afterScanFilters = filterSet -- partitionKeyFilters.filter(_.references.nonEmpty)