[SPARK-27291][SQL] PartitioningAwareFileIndex: Filter out empty files on listing files

sql/core/src/main/scala/org/apache/spark/sql/execution/DataSourceScanExec.scala

@@ -382,7 +382,7 @@ case class FileSourceScanExec(
     logInfo(s"Planning with ${bucketSpec.numBuckets} buckets")
     val filesGroupedToBuckets =
       selectedPartitions.flatMap { p =>
-        p.files.filter(_.getLen > 0).map { f =>
+        p.files.map { f =>
           PartitionedFileUtil.getPartitionedFile(f, f.getPath, p.values)
         }
       }.groupBy { f =>
@@ -426,7 +426,7 @@ case class FileSourceScanExec(
       s"open cost is considered as scanning $openCostInBytes bytes.")
 
     val splitFiles = selectedPartitions.flatMap { partition =>
-      partition.files.filter(_.getLen > 0).flatMap { file =>
+      partition.files.flatMap { file =>
         // getPath() is very expensive so we only want to call it once in this block:
         val filePath = file.getPath
         val isSplitable = relation.fileFormat.isSplitable(

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

@@ -58,15 +58,18 @@ abstract class PartitioningAwareFileIndex(
 
   override def listFiles(
       partitionFilters: Seq[Expression], dataFilters: Seq[Expression]): Seq[PartitionDirectory] = {
+    def isNonEmptyFile(f: FileStatus): Boolean = {
+      isDataPath(f.getPath) && f.getLen > 0
+    }
     val selectedPartitions = if (partitionSpec().partitionColumns.isEmpty) {
-      PartitionDirectory(InternalRow.empty, allFiles().filter(f => isDataPath(f.getPath))) :: Nil
+      PartitionDirectory(InternalRow.empty, allFiles().filter(isNonEmptyFile)) :: Nil
     } else {
       prunePartitions(partitionFilters, partitionSpec()).map {
         case PartitionPath(values, path) =>
           val files: Seq[FileStatus] = leafDirToChildrenFiles.get(path) match {
             case Some(existingDir) =>
               // Directory has children files in it, return them
-              existingDir.filter(f => isDataPath(f.getPath))
+              existingDir.filter(isNonEmptyFile)
 
             case None =>
               // Directory does not exist, or has no children files

sql/core/src/test/scala/org/apache/spark/sql/sources/SaveLoadSuite.scala

@@ -146,13 +146,15 @@ class SaveLoadSuite extends DataSourceTest with SharedSQLContext with BeforeAndA
   }
 
   test("skip empty files in non bucketed read") {
-    withTempDir { dir =>
-      val path = dir.getCanonicalPath
-      Files.write(Paths.get(path, "empty"), Array.empty[Byte])
-      Files.write(Paths.get(path, "notEmpty"), "a".getBytes(StandardCharsets.UTF_8))
-      val readback = spark.read.option("wholetext", true).text(path)
-
-      assert(readback.rdd.getNumPartitions === 1)
+    Seq("csv", "text").foreach { format =>
+      withTempDir { dir =>
+        val path = dir.getCanonicalPath
+        Files.write(Paths.get(path, "empty"), Array.empty[Byte])
+        Files.write(Paths.get(path, "notEmpty"), "a".getBytes(StandardCharsets.UTF_8))
+        val readBack = spark.read.option("wholetext", true).format(format).load(path)
+
+        assert(readBack.rdd.getNumPartitions === 1)
+      }
     }
   }
 }