Canonicalization on GetStructField

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/Canonicalize.scala

@@ -41,6 +41,7 @@ object Canonicalize {
   private[expressions] def ignoreNamesTypes(e: Expression): Expression = e match {
     case a: AttributeReference =>
       AttributeReference("none", a.dataType.asNullable)(exprId = a.exprId)
+    case GetStructField(child, ordinal, _) => GetStructField(child, ordinal, None)
     case _ => e
   }
 

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/CanonicalizeSuite.scala

@@ -20,6 +20,7 @@ package org.apache.spark.sql.catalyst.expressions
 import org.apache.spark.SparkFunSuite
 import org.apache.spark.sql.catalyst.dsl.plans._
 import org.apache.spark.sql.catalyst.plans.logical.Range
+import org.apache.spark.sql.types.{IntegerType, StructField, StructType}
 
 class CanonicalizeSuite extends SparkFunSuite {
 
@@ -50,4 +51,31 @@ class CanonicalizeSuite extends SparkFunSuite {
     assert(range.where(arrays1).sameResult(range.where(arrays2)))
     assert(!range.where(arrays1).sameResult(range.where(arrays3)))
   }
+
+  test("SPARK-26402: GetStructField with different optional names are semantically equal") {
+    val structType =
+      StructType(StructField("a", StructType(StructField("b", IntegerType) :: Nil)) :: Nil)
+    val expId = NamedExpression.newExprId
+    val qualifier = Seq.empty[String]
+
+    val fieldB1 = GetStructField(
+      AttributeReference("data1", structType, true)(expId, qualifier),
+      0, Some("b1"))
+    val fieldB2 = GetStructField(
+      AttributeReference("data2", structType, true)(expId, qualifier),
+      0, Some("b2"))
+    assert(fieldB1.semanticEquals(fieldB2))
+
+    val fieldA1 = GetStructField(
+      GetStructField(
+        AttributeReference("data1", structType, true)(expId, qualifier),
+        0, Some("a1")),
+      0, Some("b1"))
+    val fieldA2 = GetStructField(
+      GetStructField(
+        AttributeReference("data2", structType, true)(expId, qualifier),
+        0, Some("a2")),
+      0, Some("b2"))
+    assert(fieldA1.semanticEquals(fieldA2))
+  }
 }