fix

sql/core/src/main/scala/org/apache/spark/sql/DataFrameWriter.scala

@@ -244,7 +244,10 @@ final class DataFrameWriter[T] private[sql](ds: Dataset[T]) {
 
     val session = df.sparkSession
     val cls = DataSource.lookupDataSource(source, session.sessionState.conf)
-    if (classOf[TableProvider].isAssignableFrom(cls)) {
+    // SPARK-26673: In Data Source V2 project, partitioning is still under development.
+    //              Here we fallback to V1 if the write path if output partitioning is required.
+    // TODO: use V2 implementations when partitioning feature is supported.
+    if (classOf[TableProvider].isAssignableFrom(cls) && partitioningColumns.isEmpty) {
       val provider = cls.getConstructor().newInstance().asInstanceOf[TableProvider]
       val sessionOptions = DataSourceV2Utils.extractSessionConfigs(
         provider, session.sessionState.conf)

sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/v2/FileBatchWriter.scala

@@ -0,0 +1,46 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.spark.sql.execution.datasources.v2
+
+import org.apache.hadoop.mapreduce.Job
+
+import org.apache.spark.internal.io.FileCommitProtocol
+import org.apache.spark.sql.execution.datasources.{WriteJobDescription, WriteTaskResult}
+import org.apache.spark.sql.sources.v2.writer._
+import org.apache.spark.util.SerializableConfiguration
+
+class FileBatchWriter(
+    job: Job,
+    description: WriteJobDescription,
+    committer: FileCommitProtocol)
+  extends BatchWrite {
+  override def commit(messages: Array[WriterCommitMessage]): Unit = {
+    committer.commitJob(job, messages.map(_.asInstanceOf[WriteTaskResult].commitMsg))
+  }
+
+  override def useCommitCoordinator(): Boolean = false
+
+  override def abort(messages: Array[WriterCommitMessage]): Unit = {
+    committer.abortJob(job)
+  }
+
+  override def createBatchWriterFactory(): DataWriterFactory = {
+    val conf = new SerializableConfiguration(job.getConfiguration)
+    FileWriterFactory(description, committer, conf)
+  }
+}
+

sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/v2/FileWriteBuilder.scala

@@ -75,7 +75,7 @@ abstract class FileWriteBuilder(options: DataSourceOptions)
 
     job.setOutputKeyClass(classOf[Void])
     job.setOutputValueClass(classOf[InternalRow])
-    FileOutputFormat.setOutputPath(job, new Path(pathName))
+    FileOutputFormat.setOutputPath(job, path)
 
     val caseInsensitiveOptions = CaseInsensitiveMap(optionsAsScala)
     // Note: prepareWrite has side effect. It sets "job".
@@ -113,12 +113,11 @@ abstract class FileWriteBuilder(options: DataSourceOptions)
       case SaveMode.Overwrite =>
         fs.delete(path, true)
         committer.setupJob(job)
-        new FileSourceWriter(job, description, committer)
+        new FileBatchWriter(job, description, committer)
 
       case _ =>
         committer.setupJob(job)
-        new FileSourceWriter(job, description, committer)
-
+        new FileBatchWriter(job, description, committer)
     }
   }
 

sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/v2/FileSourceWriter.scala → sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/v2/FileWriterFactory.scala

@@ -18,37 +18,16 @@ package org.apache.spark.sql.execution.datasources.v2
 
 import java.util.Date
 
-import org.apache.hadoop.mapreduce.{Job, TaskAttemptID, TaskID, TaskType}
+import org.apache.hadoop.mapreduce.{TaskAttemptID, TaskID, TaskType}
 import org.apache.hadoop.mapreduce.task.TaskAttemptContextImpl
 
 import org.apache.spark.internal.io.{FileCommitProtocol, SparkHadoopWriterUtils}
 import org.apache.spark.sql.catalyst.InternalRow
-import org.apache.spark.sql.execution.datasources.{DynamicPartitionDataWriter, SingleDirectoryDataWriter, WriteJobDescription, WriteTaskResult}
-import org.apache.spark.sql.sources.v2.writer._
+import org.apache.spark.sql.execution.datasources.{DynamicPartitionDataWriter, SingleDirectoryDataWriter, WriteJobDescription}
+import org.apache.spark.sql.sources.v2.writer.{DataWriter, DataWriterFactory}
 import org.apache.spark.util.SerializableConfiguration
 
-class FileSourceWriter(
-    job: Job,
-    description: WriteJobDescription,
-    committer: FileCommitProtocol)
-  extends BatchWrite {
-  override def commit(messages: Array[WriterCommitMessage]): Unit = {
-    committer.commitJob(job, messages.map(_.asInstanceOf[WriteTaskResult].commitMsg))
-  }
-
-  override def useCommitCoordinator(): Boolean = false
-
-  override def abort(messages: Array[WriterCommitMessage]): Unit = {
-    committer.abortJob(job)
-  }
-
-  override def createBatchWriterFactory(): DataWriterFactory = {
-    val conf = new SerializableConfiguration(job.getConfiguration)
-    FileDataWriterFactory(description, committer, conf)
-  }
-}
-
-case class FileDataWriterFactory (
+case class FileWriterFactory (
     description: WriteJobDescription,
     committer: FileCommitProtocol,
     conf: SerializableConfiguration) extends DataWriterFactory {

sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/v2/orc/OrcWriteBuilder.scala

@@ -46,7 +46,6 @@ class OrcWriteBuilder(options: DataSourceOptions) extends FileWriteBuilder(optio
     conf.asInstanceOf[JobConf]
       .setOutputFormat(classOf[org.apache.orc.mapred.OrcOutputFormat[OrcStruct]])
 
-    println("v2 write...")
     new OutputWriterFactory {
       override def newInstance(
           path: String,