[SPARK-26794][SQL] SparkSession enableHiveSupport does not point to hive but in-memory while the SparkContext exists

## What changes were proposed in this pull request?

```java
public class SqlDemo {
    public static void main(final String[] args) throws Exception {
        SparkConf conf = new SparkConf().setAppName("spark-sql-demo");
        JavaSparkContext sc = new JavaSparkContext(conf);
        SparkSession ss = SparkSession.builder().enableHiveSupport().getOrCreate();
        ss.sql("show databases").show();
    }
}
```
Before https://issues.apache.org/jira/browse/SPARK-20946, the demo above point to the right hive metastore if the hive-site.xml is present. But now it can only point to the default in-memory one.

Catalog is now as a variable shared across SparkSessions, it is instantiated with SparkContext's conf. After https://issues.apache.org/jira/browse/SPARK-20946, Session level configs are not pass to SparkContext's conf anymore, so the enableHiveSupport API takes no affect on the catalog instance.

You can set spark.sql.catalogImplementation=hive application wide to solve the problem, or never create a sc before you call SparkSession.builder().enableHiveSupport().getOrCreate()

Here we respect the SparkSession level configuration at the first time to generate catalog within SharedState

## How was this patch tested?

1. add ut
2. manually
```scala
test("enableHiveSupport has right to determine the catalog while using an existing sc") {
    val conf = new SparkConf().setMaster("local").setAppName("SharedState Test")
    val sc = SparkContext.getOrCreate(conf)
    val ss = SparkSession.builder().enableHiveSupport().getOrCreate()
    assert(ss.sharedState.externalCatalog.unwrapped.isInstanceOf[HiveExternalCatalog],
      "The catalog should be hive ")

    val ss2 = SparkSession.builder().getOrCreate()
    assert(ss2.sharedState.externalCatalog.unwrapped.isInstanceOf[HiveExternalCatalog],
      "The catalog should be shared across sessions")
  }
```

Without this fix, the above test will fail.
You can apply it to `org.apache.spark.sql.hive.HiveSharedStateSuite`,
and run,
```sbt
./build/sbt  -Phadoop-2.7 -Phive  "hive/testOnly org.apache.spark.sql.hive.HiveSharedStateSuite"
```
to verify.

Closes apache#23709 from yaooqinn/SPARK-26794.

Authored-by: Kent Yao <[email protected]>
Signed-off-by: Wenchen Fan <[email protected]>

Author: yaooqinn

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

@@ -127,7 +127,7 @@ class SparkSession private(
   @Unstable
   @transient
   lazy val sharedState: SharedState = {
-    existingSharedState.getOrElse(new SharedState(sparkContext))
+    existingSharedState.getOrElse(new SharedState(sparkContext, initialSessionOptions))
   }
 
   /**

sql/core/src/main/scala/org/apache/spark/sql/internal/SharedState.scala

@@ -39,8 +39,14 @@ import org.apache.spark.util.{MutableURLClassLoader, Utils}
 
 /**
  * A class that holds all state shared across sessions in a given [[SQLContext]].
+ *
+ * @param sparkContext The Spark context associated with this SharedState
+ * @param initialConfigs The configs from the very first created SparkSession
  */
-private[sql] class SharedState(val sparkContext: SparkContext) extends Logging {
+private[sql] class SharedState(
+    val sparkContext: SparkContext,
+    initialConfigs: scala.collection.Map[String, String])
+  extends Logging {
 
   // Load hive-site.xml into hadoopConf and determine the warehouse path we want to use, based on
   // the config from both hive and Spark SQL. Finally set the warehouse config value to sparkConf.
@@ -77,6 +83,27 @@ private[sql] class SharedState(val sparkContext: SparkContext) extends Logging {
   }
   logInfo(s"Warehouse path is '$warehousePath'.")
 
+  // These 2 variables should be initiated after `warehousePath`, because in the first place we need
+  // to load hive-site.xml into hadoopConf and determine the warehouse path which will be set into
+  // both spark conf and hadoop conf avoiding be affected by any SparkSession level options
+  private val (conf, hadoopConf) = {
+    val confClone = sparkContext.conf.clone()
+    val hadoopConfClone = new Configuration(sparkContext.hadoopConfiguration)
+    // If `SparkSession` is instantiated using an existing `SparkContext` instance and no existing
+    // `SharedState`, all `SparkSession` level configurations have higher priority to generate a
+    // `SharedState` instance. This will be done only once then shared across `SparkSession`s
+    initialConfigs.foreach {
+      case (k, _)  if k == "hive.metastore.warehouse.dir" || k == WAREHOUSE_PATH.key =>
+        logWarning(s"Not allowing to set ${WAREHOUSE_PATH.key} or hive.metastore.warehouse.dir " +
+          s"in SparkSession's options, it should be set statically for cross-session usages")
+      case (k, v) =>
+        logDebug(s"Applying initial SparkSession options to SparkConf/HadoopConf: $k -> $v")
+        confClone.set(k, v)
+        hadoopConfClone.set(k, v)
+
+    }
+    (confClone, hadoopConfClone)
+  }
 
   /**
    * Class for caching query results reused in future executions.
@@ -89,7 +116,7 @@ private[sql] class SharedState(val sparkContext: SparkContext) extends Logging {
    */
   val statusStore: SQLAppStatusStore = {
     val kvStore = sparkContext.statusStore.store.asInstanceOf[ElementTrackingStore]
-    val listener = new SQLAppStatusListener(sparkContext.conf, kvStore, live = true)
+    val listener = new SQLAppStatusListener(conf, kvStore, live = true)
     sparkContext.listenerBus.addToStatusQueue(listener)
     val statusStore = new SQLAppStatusStore(kvStore, Some(listener))
     sparkContext.ui.foreach(new SQLTab(statusStore, _))
@@ -101,9 +128,7 @@ private[sql] class SharedState(val sparkContext: SparkContext) extends Logging {
    */
   lazy val externalCatalog: ExternalCatalogWithListener = {
     val externalCatalog = SharedState.reflect[ExternalCatalog, SparkConf, Configuration](
-      SharedState.externalCatalogClassName(sparkContext.conf),
-      sparkContext.conf,
-      sparkContext.hadoopConfiguration)
+      SharedState.externalCatalogClassName(conf), conf, hadoopConf)
 
     val defaultDbDefinition = CatalogDatabase(
       SessionCatalog.DEFAULT_DATABASE,
@@ -137,7 +162,7 @@ private[sql] class SharedState(val sparkContext: SparkContext) extends Logging {
     // System preserved database should not exists in metastore. However it's hard to guarantee it
     // for every session, because case-sensitivity differs. Here we always lowercase it to make our
     // life easier.
-    val globalTempDB = sparkContext.conf.get(GLOBAL_TEMP_DATABASE).toLowerCase(Locale.ROOT)
+    val globalTempDB = conf.get(GLOBAL_TEMP_DATABASE).toLowerCase(Locale.ROOT)
     if (externalCatalog.databaseExists(globalTempDB)) {
       throw new SparkException(
         s"$globalTempDB is a system preserved database, please rename your existing database " +

sql/hive/src/main/scala/org/apache/spark/sql/hive/test/TestHive.scala

@@ -90,7 +90,7 @@ private[hive] class TestHiveExternalCatalog(
 private[hive] class TestHiveSharedState(
     sc: SparkContext,
     hiveClient: Option[HiveClient] = None)
-  extends SharedState(sc) {
+  extends SharedState(sc, initialConfigs = Map.empty[String, String]) {
 
   override lazy val externalCatalog: ExternalCatalogWithListener = {
     new ExternalCatalogWithListener(new TestHiveExternalCatalog(

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

@@ -0,0 +1,66 @@
+/*
+ * 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.hive
+
+import org.apache.hadoop.hive.conf.HiveConf.ConfVars
+
+import org.apache.spark.{SparkConf, SparkContext, SparkFunSuite}
+import org.apache.spark.sql.internal.SharedState
+import org.apache.spark.sql.internal.StaticSQLConf._
+import org.apache.spark.util.Utils
+
+class HiveSharedStateSuite extends SparkFunSuite {
+
+  test("initial configs should be passed to SharedState but not SparkContext") {
+    val conf = new SparkConf().setMaster("local").setAppName("SharedState Test")
+    val sc = SparkContext.getOrCreate(conf)
+    val invalidPath = "invalid/path"
+    val metastorePath = Utils.createTempDir()
+    val tmpDb = "tmp_db"
+
+    // The initial configs used to generate SharedState, none of these should affect the global
+    // shared SparkContext's configurations. Especially, all these configs are passed to the cloned
+    // confs inside SharedState except metastore warehouse dir.
+    val initialConfigs = Map("spark.foo" -> "bar",
+      WAREHOUSE_PATH.key -> invalidPath,
+      ConfVars.METASTOREWAREHOUSE.varname -> invalidPath,
+      CATALOG_IMPLEMENTATION.key -> "hive",
+      ConfVars.METASTORECONNECTURLKEY.varname ->
+        s"jdbc:derby:;databaseName=$metastorePath/metastore_db;create=true",
+      GLOBAL_TEMP_DATABASE.key -> tmpDb)
+
+    val state = new SharedState(sc, initialConfigs)
+    assert(state.warehousePath !== invalidPath, "warehouse path can't determine by session options")
+    assert(sc.conf.get(WAREHOUSE_PATH.key) !== invalidPath,
+      "warehouse conf in session options can't affect application wide spark conf")
+    assert(sc.hadoopConfiguration.get(ConfVars.METASTOREWAREHOUSE.varname) !== invalidPath,
+      "warehouse conf in session options can't affect application wide hadoop conf")
+
+    assert(!state.sparkContext.conf.contains("spark.foo"),
+      "static spark conf should not be affected by session")
+    assert(state.externalCatalog.unwrapped.isInstanceOf[HiveExternalCatalog],
+      "Initial SparkSession options can determine the catalog")
+    val client = state.externalCatalog.unwrapped.asInstanceOf[HiveExternalCatalog].client
+    assert(client.getConf("spark.foo", "") === "bar",
+      "session level conf should be passed to catalog")
+    assert(client.getConf(ConfVars.METASTOREWAREHOUSE.varname, invalidPath) !== invalidPath,
+      "session level conf should be passed to catalog except warehouse dir")
+
+    assert(state.globalTempViewManager.database === tmpDb)
+  }
+}