[SPARK-18989][SQL] DESC TABLE should not fail with format class not found

## What changes were proposed in this pull request?

When we describe a table, we only wanna see the information of this table, not read it, so it's ok even if the format class is not present at the classpath.

## How was this patch tested?

new regression test

Author: Wenchen Fan <wenchen@databricks.com>

Closes #16388 from cloud-fan/hive.

Author: cloud-fan

sql/hive/src/main/scala/org/apache/spark/sql/hive/client/HiveClientImpl.scala

@@ -408,8 +408,15 @@ private[hive] class HiveClientImpl(
         lastAccessTime = h.getLastAccessTime.toLong * 1000,
         storage = CatalogStorageFormat(
           locationUri = shim.getDataLocation(h),
-          inputFormat = Option(h.getInputFormatClass).map(_.getName),
-          outputFormat = Option(h.getOutputFormatClass).map(_.getName),
+          // To avoid ClassNotFound exception, we try our best to not get the format class, but get
+          // the class name directly. However, for non-native tables, there is no interface to get
+          // the format class name, so we may still throw ClassNotFound in this case.
+          inputFormat = Option(h.getTTable.getSd.getInputFormat).orElse {
+            Option(h.getStorageHandler).map(_.getInputFormatClass.getName)
+          },
+          outputFormat = Option(h.getTTable.getSd.getOutputFormat).orElse {
+            Option(h.getStorageHandler).map(_.getOutputFormatClass.getName)
+          },
           serde = Option(h.getSerializationLib),
           compressed = h.getTTable.getSd.isCompressed,
           properties = Option(h.getTTable.getSd.getSerdeInfo.getParameters)

sql/hive/src/test/scala/org/apache/spark/sql/hive/HiveSparkSubmitSuite.scala

@@ -311,6 +311,29 @@ class HiveSparkSubmitSuite
     runSparkSubmit(args)
   }
 
+  test("SPARK-18989: DESC TABLE should not fail with format class not found") {
+    val unusedJar = TestUtils.createJarWithClasses(Seq.empty)
+
+    val argsForCreateTable = Seq(
+      "--class", SPARK_18989_CREATE_TABLE.getClass.getName.stripSuffix("$"),
+      "--name", "SPARK-18947",
+      "--master", "local-cluster[2,1,1024]",
+      "--conf", "spark.ui.enabled=false",
+      "--conf", "spark.master.rest.enabled=false",
+      "--jars", TestHive.getHiveFile("hive-contrib-0.13.1.jar").getCanonicalPath,
+      unusedJar.toString)
+    runSparkSubmit(argsForCreateTable)
+
+    val argsForShowTables = Seq(
+      "--class", SPARK_18989_DESC_TABLE.getClass.getName.stripSuffix("$"),
+      "--name", "SPARK-18947",
+      "--master", "local-cluster[2,1,1024]",
+      "--conf", "spark.ui.enabled=false",
+      "--conf", "spark.master.rest.enabled=false",
+      unusedJar.toString)
+    runSparkSubmit(argsForShowTables)
+  }
+
   // NOTE: This is an expensive operation in terms of time (10 seconds+). Use sparingly.
   // This is copied from org.apache.spark.deploy.SparkSubmitSuite
   private def runSparkSubmit(args: Seq[String]): Unit = {
@@ -853,3 +876,26 @@ object SPARK_18360 {
     }
   }
 }
+
+object SPARK_18989_CREATE_TABLE {
+  def main(args: Array[String]): Unit = {
+    val spark = SparkSession.builder().enableHiveSupport().getOrCreate()
+    spark.sql(
+      """
+        |CREATE TABLE IF NOT EXISTS base64_tbl(val string) STORED AS
+        |INPUTFORMAT 'org.apache.hadoop.hive.contrib.fileformat.base64.Base64TextInputFormat'
+        |OUTPUTFORMAT 'org.apache.hadoop.hive.contrib.fileformat.base64.Base64TextOutputFormat'
+      """.stripMargin)
+  }
+}
+
+object SPARK_18989_DESC_TABLE {
+  def main(args: Array[String]): Unit = {
+    val spark = SparkSession.builder().enableHiveSupport().getOrCreate()
+    try {
+      spark.sql("DESC base64_tbl")
+    } finally {
+      spark.sql("DROP TABLE IF EXISTS base64_tbl")
+    }
+  }
+}