Address comments.

Author: ueshin

core/src/main/scala/org/apache/spark/SparkContext.scala

@@ -2562,7 +2562,7 @@ object SparkContext extends Logging {
    *
    * Throws an exception if a SparkContext is about to be created in executors.
    */
-  private[spark] def assertOnDriver(): Unit = {
+  private def assertOnDriver(): Unit = {
     if (TaskContext.get != null) {
       // we're accessing it during task execution, fail.
       throw new IllegalStateException(

core/src/test/scala/org/apache/spark/SparkContextSuite.scala

@@ -935,7 +935,7 @@ class SparkContextSuite extends SparkFunSuite with LocalSparkContext with Eventu
     }
   }
 
-  test("Disallow to create SparkContext in executors") {
+  test("SPARK-32160: Disallow to create SparkContext in executors") {
     sc = new SparkContext(new SparkConf().setAppName("test").setMaster("local-cluster[3, 1, 1024]"))
 
     val error = intercept[SparkException] {

python/pyspark/tests/test_context.py

@@ -268,6 +268,7 @@ def test_resources(self):
             self.assertEqual(len(resources), 0)
 
     def test_disallow_to_create_spark_context_in_executors(self):
+        # SPARK-32160: SparkContext should not be created in executors.
         with SparkContext("local-cluster[3, 1, 1024]") as sc:
             with self.assertRaises(Exception) as context:
                 sc.range(2).foreach(lambda _: SparkContext())