from_protobuf (part 1): Add ordinal remapping for GetStructField/GetArrayStructFields

sql-plugin/src/main/scala/com/nvidia/spark/rapids/GpuOverrides.scala

@@ -955,6 +955,7 @@ object GpuOverrides extends Logging {
             + GpuTypeShims.additionalCommonOperatorSupportedTypes).nested(),
         TypeSig.all),
       (a, conf, p, r) => new UnaryAstExprMeta[Alias](a, conf, p, r) {
+        override def typeMeta: DataTypeMeta = childExprs.head.typeMeta
         override def convertToGpu(child: Expression): GpuExpression =
           GpuAlias(child, a.name)(a.exprId, a.qualifier, a.explicitMetadata)
       }),
@@ -2628,10 +2629,7 @@ object GpuOverrides extends Logging {
         TypeSig.STRUCT.nested(TypeSig.commonCudfTypes + TypeSig.ARRAY +
             TypeSig.STRUCT + TypeSig.MAP + TypeSig.NULL + TypeSig.DECIMAL_128 + TypeSig.BINARY),
         TypeSig.STRUCT.nested(TypeSig.all)),
-      (expr, conf, p, r) => new UnaryExprMeta[GetStructField](expr, conf, p, r) {
-        override def convertToGpu(arr: Expression): GpuExpression =
-          GpuGetStructField(arr, expr.ordinal, expr.name)
-      }),
+      (expr, conf, p, r) => new GpuGetStructFieldMeta(expr, conf, p, r)),
     expr[GetArrayItem](
       "Gets the field at `ordinal` in the Array",
       ExprChecks.binaryProject(

sql-plugin/src/main/scala/org/apache/spark/sql/rapids/complexTypeExtractors.scala

@@ -402,15 +402,68 @@ case class GpuArrayPosition(left: Expression, right: Expression)
   }
 }
 
+object GpuStructFieldOrdinalTag {
+  val PRUNED_ORDINAL_TAG =
+    new org.apache.spark.sql.catalyst.trees.TreeNodeTag[Int]("GPU_PRUNED_ORDINAL")
+}
+
+class GpuGetStructFieldMeta(
+    expr: GetStructField,
+    conf: RapidsConf,
+    parent: Option[RapidsMeta[_, _, _]],
+    rule: DataFromReplacementRule)
+  extends UnaryExprMeta[GetStructField](expr, conf, parent, rule) {
+
+  override def convertToGpu(child: Expression): GpuExpression = {
+    val effectiveOrd = GpuGetStructFieldMeta.effectiveOrdinal(expr)
+    GpuGetStructField(child, effectiveOrd, expr.name)
+  }
+}
+
+object GpuGetStructFieldMeta {
+  def effectiveOrdinal(expr: GetStructField): Int = {
+    val runtimeOrd = expr.getTagValue(
+      GpuStructFieldOrdinalTag.PRUNED_ORDINAL_TAG).getOrElse(-1)
+    if (runtimeOrd >= 0) {
+      runtimeOrd
+    } else {
+      expr.ordinal
+    }
+  }
+}
+
 class GpuGetArrayStructFieldsMeta(
      expr: GetArrayStructFields,
      conf: RapidsConf,
      parent: Option[RapidsMeta[_, _, _]],
      rule: DataFromReplacementRule)
   extends UnaryExprMeta[GetArrayStructFields](expr, conf, parent, rule) {
 
-  def convertToGpu(child: Expression): GpuExpression =
-    GpuGetArrayStructFields(child, expr.field, expr.ordinal, expr.numFields, expr.containsNull)
+  override def convertToGpu(child: Expression): GpuExpression = {
+    val runtimeOrd = expr.getTagValue(
+      GpuStructFieldOrdinalTag.PRUNED_ORDINAL_TAG).getOrElse(-1)
+    val effectiveOrd = if (runtimeOrd >= 0) runtimeOrd else expr.ordinal
+    val effectiveNumFields =
+      GpuGetArrayStructFieldsMeta.effectiveNumFields(child, expr, runtimeOrd)
+    GpuGetArrayStructFields(child, expr.field,
+      effectiveOrd, effectiveNumFields, expr.containsNull)
+  }
+}
+
+object GpuGetArrayStructFieldsMeta {
+  def effectiveNumFields(
+      child: Expression,
+      expr: GetArrayStructFields,
+      runtimeOrd: Int): Int = {
+    if (runtimeOrd >= 0) {
+      child.dataType match {
+        case ArrayType(st: StructType, _) => st.fields.length
+        case _ => expr.numFields
+      }
+    } else {
+      expr.numFields
+    }
+  }
 }
 
 /**

sql-plugin/src/test/scala/com/nvidia/spark/rapids/StructFieldOrdinalTagSuite.scala

@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2026, NVIDIA CORPORATION.
+ *
+ * Licensed 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 com.nvidia.spark.rapids
+
+import org.scalatest.funsuite.AnyFunSuite
+
+import org.apache.spark.sql.catalyst.expressions.{
+  AttributeReference,
+  GetArrayStructFields,
+  GetStructField
+}
+import org.apache.spark.sql.rapids.{
+  GpuGetArrayStructFieldsMeta,
+  GpuGetStructFieldMeta,
+  GpuStructFieldOrdinalTag
+}
+import org.apache.spark.sql.types._
+
+class StructFieldOrdinalTagSuite extends AnyFunSuite {
+
+  private val threeFieldStruct = StructType(Seq(
+    StructField("a", IntegerType, nullable = true),
+    StructField("b", StringType, nullable = true),
+    StructField("c", DoubleType, nullable = true)))
+
+  private val structAttr = AttributeReference("s", threeFieldStruct, nullable = true)()
+
+  private val arrayOfStruct = ArrayType(threeFieldStruct, containsNull = false)
+  private val arrayAttr = AttributeReference("arr", arrayOfStruct, nullable = true)()
+
+  // ---------- GetStructField ordinal tag ----------
+
+  test("effectiveOrdinal returns original ordinal when no tag is set") {
+    val gsf = GetStructField(structAttr, 2, Some("c"))
+    assert(GpuGetStructFieldMeta.effectiveOrdinal(gsf) === 2)
+  }
+
+  test("effectiveOrdinal returns tagged ordinal when tag is set") {
+    val gsf = GetStructField(structAttr, 2, Some("c"))
+    gsf.setTagValue(GpuStructFieldOrdinalTag.PRUNED_ORDINAL_TAG, 0)
+    assert(GpuGetStructFieldMeta.effectiveOrdinal(gsf) === 0)
+  }
+
+  // ---------- effectiveNumFields ----------
+
+  test("effectiveNumFields returns original numFields when no tag") {
+    val gasf = GetArrayStructFields(arrayAttr, threeFieldStruct(1), 1, 3, false)
+    val result = GpuGetArrayStructFieldsMeta.effectiveNumFields(arrayAttr, gasf, -1)
+    assert(result === 3)
+  }
+
+  test("effectiveNumFields derives from child type when tag is active") {
+    val prunedStruct = StructType(Seq(
+      StructField("b", StringType, nullable = true)))
+    val prunedArrayType = ArrayType(prunedStruct, containsNull = false)
+    val prunedChild = AttributeReference("arr", prunedArrayType, nullable = true)()
+
+    val gasf = GetArrayStructFields(arrayAttr, threeFieldStruct(1), 1, 3, false)
+    val result = GpuGetArrayStructFieldsMeta.effectiveNumFields(prunedChild, gasf, 0)
+    assert(result === 1)
+  }
+
+  test("effectiveNumFields falls back to expr.numFields for non-array child type") {
+    val nonArrayChild = AttributeReference("x", IntegerType, nullable = true)()
+    val gasf = GetArrayStructFields(arrayAttr, threeFieldStruct(0), 0, 3, false)
+    val result = GpuGetArrayStructFieldsMeta.effectiveNumFields(nonArrayChild, gasf, 0)
+    assert(result === 3)
+  }
+
+}