Revert "[VL][Iceberg] Register iceberg spark session extensions automatically"

backends-velox/src-iceberg/main/scala/org/apache/gluten/component/VeloxIcebergComponent.scala

@@ -23,19 +23,15 @@ import org.apache.gluten.extension.injector.Injector
 import org.apache.spark.util.SparkReflectionUtil
 
 class VeloxIcebergComponent extends Component {
-  private val icebergSparkSessionExtension =
-    "org.apache.iceberg.spark.extensions.IcebergSparkSessionExtensions"
-
   override def name(): String = "velox-iceberg"
 
   override def dependencies(): Seq[Class[_ <: Component]] = classOf[VeloxBackend] :: Nil
 
   override def isRuntimeCompatible: Boolean = {
-    SparkReflectionUtil.isClassPresent(icebergSparkSessionExtension)
+    SparkReflectionUtil.isClassPresent(
+      "org.apache.iceberg.spark.extensions.IcebergSparkSessionExtensions")
   }
 
-  override def sparkSessionExtensions(): Seq[String] = icebergSparkSessionExtension :: Nil
-
   override def injectRules(injector: Injector): Unit = {
     OffloadIcebergScan.inject(injector)
     OffloadIcebergWrite.inject(injector)

gluten-core/src/main/scala/org/apache/gluten/GlutenPlugin.scala

@@ -50,11 +50,17 @@ private[gluten] class GlutenDriverPlugin extends DriverPlugin with Logging {
 
   override def init(sc: SparkContext, pluginContext: PluginContext): util.Map[String, String] = {
     val conf = pluginContext.conf()
-    val components = Component.sorted()
-    configureSessionExtensions(conf, components)
+    // Spark SQL extensions
+    val extensionSeq = conf.get(SPARK_SESSION_EXTENSIONS).getOrElse(Seq.empty)
+    if (!extensionSeq.toSet.contains(GlutenSessionExtensions.GLUTEN_SESSION_EXTENSION_NAME)) {
+      conf.set(
+        SPARK_SESSION_EXTENSIONS,
+        extensionSeq :+ GlutenSessionExtensions.GLUTEN_SESSION_EXTENSION_NAME)
+    }
 
     setPredefinedConfigs(conf)
 
+    val components = Component.sorted()
     printComponentInfo(components)
     setComponentInfoConfig(conf, components)
     components.foreach(_.onDriverStart(sc, pluginContext))
@@ -71,19 +77,6 @@ private[gluten] class GlutenDriverPlugin extends DriverPlugin with Logging {
 }
 
 private object GlutenDriverPlugin extends Logging {
-  private[gluten] def configureSessionExtensions(
-      conf: SparkConf,
-      components: Seq[Component]): Unit = {
-    val configuredExtensions = conf.get(SPARK_SESSION_EXTENSIONS).getOrElse(Seq.empty)
-    val requiredExtensions =
-      components.flatMap(_.sparkSessionExtensions()) :+
-        GlutenSessionExtensions.GLUTEN_SESSION_EXTENSION_NAME
-    val mergedExtensions = (configuredExtensions ++ requiredExtensions).distinct
-    if (mergedExtensions != configuredExtensions) {
-      conf.set(SPARK_SESSION_EXTENSIONS, mergedExtensions)
-    }
-  }
-
   private def checkOffHeapSettings(conf: SparkConf): Unit = {
     if (conf.get(GlutenCoreConfig.DYNAMIC_OFFHEAP_SIZING_ENABLED)) {
       // When dynamic off-heap sizing is enabled, off-heap mode is not strictly required to be

gluten-core/src/main/scala/org/apache/gluten/component/Component.scala

@@ -79,8 +79,6 @@ trait Component {
   def info(): Map[String, String] = Map.empty
   def dependencies(): Seq[Class[_ <: Component]]
 
-  def sparkSessionExtensions(): Seq[String] = Nil
-
   /** Spark listeners. */
   def onDriverStart(sc: SparkContext, pc: PluginContext): Unit = {}
   def onDriverShutdown(): Unit = {}

gluten-iceberg/src/test/scala/org/apache/gluten/execution/IcebergSuite.scala

@@ -37,21 +37,14 @@ abstract class IcebergSuite extends WholeStageTransformerSuite {
       .set("spark.memory.offHeap.size", "2g")
       .set("spark.unsafe.exceptionOnMemoryLeak", "true")
       .set("spark.sql.autoBroadcastJoinThreshold", "-1")
+      .set(
+        "spark.sql.extensions",
+        "org.apache.iceberg.spark.extensions.IcebergSparkSessionExtensions")
       .set("spark.sql.catalog.spark_catalog", "org.apache.iceberg.spark.SparkCatalog")
       .set("spark.sql.catalog.spark_catalog.type", "hadoop")
       .set("spark.sql.catalog.spark_catalog.warehouse", s"file://$rootPath/tpch-data-iceberg-velox")
   }
 
-  test("iceberg system procedures are registered by the Gluten plugin") {
-    spark.sessionState.sqlParser.parsePlan(
-      """
-        |CALL spark_catalog.system.register_table(
-        |  table => 'default.issue_12693',
-        |  metadata_file => 'file:///tmp/does-not-exist.metadata.json'
-        |)
-        |""".stripMargin)
-  }
-
   test("iceberg transformer exists") {
     withTable("iceberg_tb") {
       spark.sql("""