[SPARK-45920][SQL] group by ordinal should be idempotent

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Analyzer.scala

@@ -1999,7 +1999,19 @@ class Analyzer(override val catalogManager: CatalogManager) extends RuleExecutor
               throw QueryCompilationErrors.groupByPositionRefersToAggregateFunctionError(
                 index, ordinalExpr)
             } else {
-              ordinalExpr
+              trimAliases(ordinalExpr) match {
+                // HACK ALERT: If the ordinal expression is also an integer literal, don't use it
+                //             but still keep the ordinal literal. The reason is we may repeatedly
+                //             analyze the plan. Using a different integer literal may lead to
+                //             a repeat GROUP BY ordinal resolution which is wrong. GROUP BY
+                //             constant is meaningless so whatever value does not matter here.
+                // TODO: (SPARK-45932) GROUP BY ordinal should pull out grouping expressions to
+                //       a Project, then the resolved ordinal expression is always
+                //       `AttributeReference`.
+                case Literal(_: Int, IntegerType) =>
+                  Literal(index)
+                case _ => ordinalExpr
+              }
             }
           } else {
             throw QueryCompilationErrors.groupByPositionRangeError(index, aggs.size)

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/analysis/SubstituteUnresolvedOrdinalsSuite.scala

@@ -17,10 +17,11 @@
 
 package org.apache.spark.sql.catalyst.analysis
 
-import org.apache.spark.sql.catalyst.analysis.TestRelations.testRelation2
+import org.apache.spark.sql.catalyst.analysis.TestRelations.{testRelation, testRelation2}
 import org.apache.spark.sql.catalyst.dsl.expressions._
 import org.apache.spark.sql.catalyst.dsl.plans._
-import org.apache.spark.sql.catalyst.expressions.Literal
+import org.apache.spark.sql.catalyst.expressions.{GenericInternalRow, Literal}
+import org.apache.spark.sql.catalyst.plans.logical.LocalRelation
 import org.apache.spark.sql.internal.SQLConf
 
 class SubstituteUnresolvedOrdinalsSuite extends AnalysisTest {
@@ -67,4 +68,22 @@ class SubstituteUnresolvedOrdinalsSuite extends AnalysisTest {
         testRelation2.groupBy(Literal(1), Literal(2))($"a", $"b"))
     }
   }
+
+  test("SPARK-45920: group by ordinal repeated analysis") {
+    val plan = testRelation.groupBy(Literal(1))(Literal(100).as("a")).analyze
+    comparePlans(
+      plan,
+      testRelation.groupBy(Literal(1))(Literal(100).as("a"))
+    )
+
+    val testRelationWithData = testRelation.copy(data = Seq(new GenericInternalRow(Array(1: Any))))
+    // Copy the plan to reset its `analyzed` flag, so that analyzer rules will re-apply.
+    val copiedPlan = plan.transform {
+      case _: LocalRelation => testRelationWithData
+    }
+    comparePlans(
+      copiedPlan.analyze, // repeated analysis
+      testRelationWithData.groupBy(Literal(1))(Literal(100).as("a"))
+    )
+  }
 }

sql/core/src/test/resources/sql-tests/analyzer-results/group-by-ordinal.sql.out

@@ -61,7 +61,7 @@ Aggregate [a#x, a#x], [a#x, 1 AS 1#x, sum(b#x) AS sum(b)#xL]
 -- !query
 select a, 1, sum(b) from data group by 1, 2
 -- !query analysis
-Aggregate [a#x, 1], [a#x, 1 AS 1#x, sum(b#x) AS sum(b)#xL]
+Aggregate [a#x, 2], [a#x, 1 AS 1#x, sum(b#x) AS sum(b)#xL]
 +- SubqueryAlias data
    +- View (`data`, [a#x,b#x])
       +- Project [cast(a#x as int) AS a#x, cast(b#x as int) AS b#x]