address comment

gluten-core/src/main/scala/org/apache/gluten/extension/columnar/OffloadSingleNode.scala

@@ -213,7 +213,7 @@ case class OffloadFilter() extends OffloadSingleNode with LogLevelUtil {
     // Push down the left conditions in Filter into FileSourceScan.
     val newChild: SparkPlan = filter.child match {
       case scan @ (_: FileSourceScanExec | _: BatchScanExec) =>
-        if (!TransformHints.isNotTransformable(scan)) {
+        if (TransformHints.maybeTransformable(scan)) {
           val newScan =
             FilterHandler.pushFilterToScan(filter.condition, scan)
           newScan match {

gluten-core/src/main/scala/org/apache/gluten/extension/columnar/TransformHintRule.scala

@@ -78,6 +78,14 @@ object TransformHints {
     }
   }
 
+  /**
+   * If true, it implies the plan maybe transformable during validation phase but not guaranteed,
+   * since another validation rule could turn it to "non-transformable" before implementing the plan
+   * within Gluten transformers. If false, the plan node will be guaranteed fallback to Vanilla plan
+   * node while being implemented.
+   */
+  def maybeTransformable(plan: SparkPlan): Boolean = !isNotTransformable(plan)
+
   def tag(plan: SparkPlan, hint: TransformHint): Unit = {
     val mergedHint = getHintOption(plan)
       .map {

gluten-core/src/main/scala/org/apache/gluten/extension/columnar/rewrite/RewriteSparkPlanRulesManager.scala

@@ -49,7 +49,7 @@ class RewriteSparkPlanRulesManager private (rewriteRules: Seq[RewriteSingleNode]
   extends Rule[SparkPlan] {
 
   private def mayNeedRewrite(plan: SparkPlan): Boolean = {
-    !TransformHints.isNotTransformable(plan) && {
+    TransformHints.maybeTransformable(plan) && {
       plan match {
         case _: SortExec => true
         case _: TakeOrderedAndProjectExec => true