[SPARK-3698][SQL] Fix case insensitive resolution of GetField.

Based on #2543.

Author: Michael Armbrust <michael@databricks.com>

Closes #3724 from marmbrus/resolveGetField and squashes the following commits:

0a47aae [Michael Armbrust] Fix case insensitive resolution of GetField.

2 files changed, 17 insertions, 1 deletions

diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Analyzer.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Analyzer.scala
index ea9bb39786..3705fcc1f1 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Analyzer.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Analyzer.scala
@@ -21,6 +21,7 @@ import org.apache.spark.sql.catalyst.errors.TreeNodeException
 import org.apache.spark.sql.catalyst.expressions._
 import org.apache.spark.sql.catalyst.plans.logical._
 import org.apache.spark.sql.catalyst.rules._
+import org.apache.spark.sql.catalyst.types.StructType
 
 /**
  * A trivial [[Analyzer]] with an [[EmptyCatalog]] and [[EmptyFunctionRegistry]]. Used for testing
@@ -187,6 +188,15 @@ class Analyzer(catalog: Catalog,
             val result = q.resolveChildren(name, resolver).getOrElse(u)
             logDebug(s"Resolving $u to $result")
             result
+
+          // Resolve field names using the resolver.
+          case f @ GetField(child, fieldName) if !f.resolved && child.resolved =>
+            child.dataType match {
+              case StructType(fields) =>
+                val resolvedFieldName = fields.map(_.name).find(resolver(_, fieldName))
+                resolvedFieldName.map(n => f.copy(fieldName = n)).getOrElse(f)
+              case _ => f
+            }
         }
     }
 
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/complexTypes.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/complexTypes.scala
index 917b346086..b12821d44b 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/complexTypes.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/complexTypes.scala
@@ -92,7 +92,13 @@ case class GetField(child: Expression, fieldName: String) extends UnaryExpressio
 
   lazy val ordinal = structType.fields.indexOf(field)
 
-  override lazy val resolved = childrenResolved && child.dataType.isInstanceOf[StructType]
+  override lazy val resolved = childrenResolved && fieldResolved
+
+  /** Returns true only if the fieldName is found in the child struct. */
+  private def fieldResolved = child.dataType match {
+    case StructType(fields) => fields.map(_.name).contains(fieldName)
+    case _ => false
+  }
 
   override def eval(input: Row): Any = {
     val baseValue = child.eval(input).asInstanceOf[Row]