[GitHub] [spark] anchovYu commented on a diff in pull request #42276: [WIP] Throw a more tailored error message for having - window - LCA unresolved case

["anchovYu (via GitHub)" <gi...@apache.org>]

anchovYu commented on code in PR #42276:
URL: https://github.com/apache/spark/pull/42276#discussion_r1285473731


##########
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/ResolveLateralColumnAliasReference.scala:
##########
@@ -131,138 +131,166 @@ object ResolveLateralColumnAliasReference extends Rule[LogicalPlan] {
       (pList.exists(hasWindowExpression) && p.expressions.forall(_.resolved) && p.childrenResolved)
   }
 
-  override def apply(plan: LogicalPlan): LogicalPlan = {
-    if (!conf.getConf(SQLConf.LATERAL_COLUMN_ALIAS_IMPLICIT_ENABLED)) {
-      plan
-    } else if (plan.containsAnyPattern(TEMP_RESOLVED_COLUMN, UNRESOLVED_HAVING)) {
-      // It should not change the plan if `TempResolvedColumn` or `UnresolvedHaving` is present in
-      // the query plan. These plans need certain plan shape to get recognized and resolved by other
-      // rules, such as Filter/Sort + Aggregate to be matched by ResolveAggregateFunctions.
-      // LCA resolution can break the plan shape, like adding Project above Aggregate.
-      plan
-    } else {
-      // phase 2: unwrap
-      plan.resolveOperatorsUpWithPruning(
-        _.containsPattern(LATERAL_COLUMN_ALIAS_REFERENCE), ruleId) {
-        case p @ Project(projectList, child) if ruleApplicableOnOperator(p, projectList)
-          && projectList.exists(_.containsPattern(LATERAL_COLUMN_ALIAS_REFERENCE)) =>
-          var aliasMap = AttributeMap.empty[AliasEntry]
-          val referencedAliases = collection.mutable.Set.empty[AliasEntry]
-          def unwrapLCAReference(e: NamedExpression): NamedExpression = {
-            e.transformWithPruning(_.containsPattern(LATERAL_COLUMN_ALIAS_REFERENCE)) {
-              case lcaRef: LateralColumnAliasReference if aliasMap.contains(lcaRef.a) =>
-                val aliasEntry = aliasMap.get(lcaRef.a).get
-                // If there is no chaining of lateral column alias reference, push down the alias
-                // and unwrap the LateralColumnAliasReference to the NamedExpression inside
-                // If there is chaining, don't resolve and save to future rounds
-                if (!aliasEntry.alias.containsPattern(LATERAL_COLUMN_ALIAS_REFERENCE)) {
-                  referencedAliases += aliasEntry
-                  lcaRef.ne
-                } else {
-                  lcaRef
-                }
-              case lcaRef: LateralColumnAliasReference if !aliasMap.contains(lcaRef.a) =>
-                // It shouldn't happen, but restore to unresolved attribute to be safe.
-                UnresolvedAttribute(lcaRef.nameParts)
-            }.asInstanceOf[NamedExpression]
-          }
-          val newProjectList = projectList.zipWithIndex.map {
-            case (a: Alias, idx) =>
-              val lcaResolved = unwrapLCAReference(a)
-              // Insert the original alias instead of rewritten one to detect chained LCA
-              aliasMap += (a.toAttribute -> AliasEntry(a, idx))
-              lcaResolved
-            case (e, _) =>
-              unwrapLCAReference(e)
-          }
+  /** Internal application method. A hand-written top down recursive traverse. */
+  private def apply0(plan: LogicalPlan): LogicalPlan = {
+    plan match {
+      case p: LogicalPlan if !p.containsPattern(LATERAL_COLUMN_ALIAS_REFERENCE) =>
+        p
 
-          if (referencedAliases.isEmpty) {
-            p
-          } else {
-            val outerProjectList = collection.mutable.Seq(newProjectList: _*)
-            val innerProjectList =
-              collection.mutable.ArrayBuffer(child.output.map(_.asInstanceOf[NamedExpression]): _*)
-            referencedAliases.foreach { case AliasEntry(alias: Alias, idx) =>
-              outerProjectList.update(idx, alias.toAttribute)
-              innerProjectList += alias
-            }
-            p.copy(
-              projectList = outerProjectList.toSeq,
-              child = Project(innerProjectList.toSeq, child)
-            )
-          }
+      // It should not change the Aggregate (and thus the plan shape) if its parent is an
+      // UnresolvedHaving, to avoid breaking the shape pattern  `UnresolvedHaving - Aggregate`
+      // matched by ResolveAggregateFunctions. See SPARK-42936 for more details.
+      case u @ UnresolvedHaving(_, agg: Aggregate)
+        if agg.aggregateExpressions.exists(_.containsPattern(LATERAL_COLUMN_ALIAS_REFERENCE)) =>
+        u.copy(child = agg.mapChildren(apply0))
 
-        case agg @ Aggregate(groupingExpressions, aggregateExpressions, _)
-          if ruleApplicableOnOperator(agg, aggregateExpressions)
-            && aggregateExpressions.exists(_.containsPattern(LATERAL_COLUMN_ALIAS_REFERENCE)) =>
+      case p @ Project(projectList, child) if ruleApplicableOnOperator(p, projectList)

Review Comment:
   Completely copied the original code except adding the final line to recursively iterating children



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