[SPARK-3729][SQL] Do all hive session state initialization in lazy val

This change avoids a NPE during context initialization when settings are present.

Author: Michael Armbrust <michael@databricks.com>

Closes #2583 from marmbrus/configNPE and squashes the following commits:

da2ec57 [Michael Armbrust] Do all hive session state initilialization in lazy val

2 files changed, 7 insertions, 5 deletions

diff --git a/sql/hive/src/main/scala/org/apache/spark/sql/hive/HiveContext.scala b/sql/hive/src/main/scala/org/apache/spark/sql/hive/HiveContext.scala
index 20ebe4996c..fdb56901f9 100644
--- a/sql/hive/src/main/scala/org/apache/spark/sql/hive/HiveContext.scala
+++ b/sql/hive/src/main/scala/org/apache/spark/sql/hive/HiveContext.scala
@@ -231,12 +231,13 @@ class HiveContext(sc: SparkContext) extends SQLContext(sc) {
   @transient protected[hive] lazy val sessionState = {
     val ss = new SessionState(hiveconf)
     setConf(hiveconf.getAllProperties)  // Have SQLConf pick up the initial set of HiveConf.
+    SessionState.start(ss)
+    ss.err = new PrintStream(outputBuffer, true, "UTF-8")
+    ss.out = new PrintStream(outputBuffer, true, "UTF-8")
+
     ss
   }
 
-  sessionState.err = new PrintStream(outputBuffer, true, "UTF-8")
-  sessionState.out = new PrintStream(outputBuffer, true, "UTF-8")
-
   override def setConf(key: String, value: String): Unit = {
     super.setConf(key, value)
     runSqlHive(s"SET $key=$value")
@@ -273,7 +274,6 @@ class HiveContext(sc: SparkContext) extends SQLContext(sc) {
     results
   }
 
-  SessionState.start(sessionState)
 
   /**
    * Execute the command using Hive and return the results as a sequence. Each element
diff --git a/sql/hive/src/main/scala/org/apache/spark/sql/hive/TestHive.scala b/sql/hive/src/main/scala/org/apache/spark/sql/hive/TestHive.scala
index 70fb15259e..4a999b98ad 100644
--- a/sql/hive/src/main/scala/org/apache/spark/sql/hive/TestHive.scala
+++ b/sql/hive/src/main/scala/org/apache/spark/sql/hive/TestHive.scala
@@ -40,8 +40,10 @@ import org.apache.spark.sql.SQLConf
 /* Implicit conversions */
 import scala.collection.JavaConversions._
 
+// SPARK-3729: Test key required to check for initialization errors with config.
 object TestHive
-  extends TestHiveContext(new SparkContext("local[2]", "TestSQLContext", new SparkConf()))
+  extends TestHiveContext(
+    new SparkContext("local[2]", "TestSQLContext", new SparkConf().set("spark.sql.test", "")))
 
 /**
  * A locally running test instance of Spark's Hive execution engine.