From b2332f2ea03307ee6bc0e2e62fa5f364f7340039 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Mon, 11 Mar 2024 09:15:33 +0100
Subject: [PATCH v3 7/8] Simplify range_table_mutator_impl() and
 range_table_entry_walker_impl()

This is part of an effort to reduce the number of special cases in the
node support functions.

This patch removes the switch on rtekind from
range_table_mutator_impl() and range_table_entry_walker_impl().  This
should be fine because all the subroutines can handle unset/NULL
fields.  And it removes one more place that needs to track knowledge
about which fields are valid when.

Discussion: https://www.postgresql.org/message-id/flat/4b27fc50-8cd6-46f5-ab20-88dbaadca645@eisentraut.org
---
 src/backend/nodes/nodeFuncs.c | 110 ++++++++++++----------------------
 1 file changed, 37 insertions(+), 73 deletions(-)

diff --git a/src/backend/nodes/nodeFuncs.c b/src/backend/nodes/nodeFuncs.c
index db1b9bec13..410f700ee5 100644
--- a/src/backend/nodes/nodeFuncs.c
+++ b/src/backend/nodes/nodeFuncs.c
@@ -2699,41 +2699,20 @@ range_table_entry_walker_impl(RangeTblEntry *rte,
 		if (WALK(rte))
 			return true;
 
-	switch (rte->rtekind)
-	{
-		case RTE_RELATION:
-			if (WALK(rte->tablesample))
-				return true;
-			break;
-		case RTE_SUBQUERY:
-			if (!(flags & QTW_IGNORE_RT_SUBQUERIES))
-				if (WALK(rte->subquery))
-					return true;
-			break;
-		case RTE_JOIN:
-			if (!(flags & QTW_IGNORE_JOINALIASES))
-				if (WALK(rte->joinaliasvars))
-					return true;
-			break;
-		case RTE_FUNCTION:
-			if (WALK(rte->functions))
-				return true;
-			break;
-		case RTE_TABLEFUNC:
-			if (WALK(rte->tablefunc))
-				return true;
-			break;
-		case RTE_VALUES:
-			if (WALK(rte->values_lists))
-				return true;
-			break;
-		case RTE_CTE:
-		case RTE_NAMEDTUPLESTORE:
-		case RTE_RESULT:
-			/* nothing to do */
-			break;
-	}
-
+	if (WALK(rte->tablesample))
+		return true;
+	if (!(flags & QTW_IGNORE_RT_SUBQUERIES))
+		if (WALK(rte->subquery))
+			return true;
+	if (!(flags & QTW_IGNORE_JOINALIASES))
+		if (WALK(rte->joinaliasvars))
+			return true;
+	if (WALK(rte->functions))
+		return true;
+	if (WALK(rte->tablefunc))
+		return true;
+	if (WALK(rte->values_lists))
+		return true;
 	if (WALK(rte->securityQuals))
 		return true;
 
@@ -3693,47 +3672,32 @@ range_table_mutator_impl(List *rtable,
 		RangeTblEntry *newrte;
 
 		FLATCOPY(newrte, rte, RangeTblEntry);
-		switch (rte->rtekind)
+
+		MUTATE(newrte->tablesample, rte->tablesample, TableSampleClause *);
+
+		if (!(flags & QTW_IGNORE_RT_SUBQUERIES))
+			MUTATE(newrte->subquery, rte->subquery, Query *);
+		else
 		{
-			case RTE_RELATION:
-				MUTATE(newrte->tablesample, rte->tablesample,
-					   TableSampleClause *);
-				/* we don't bother to copy eref, aliases, etc; OK? */
-				break;
-			case RTE_SUBQUERY:
-				if (!(flags & QTW_IGNORE_RT_SUBQUERIES))
-					MUTATE(newrte->subquery, rte->subquery, Query *);
-				else
-				{
-					/* else, copy RT subqueries as-is */
-					newrte->subquery = copyObject(rte->subquery);
-				}
-				break;
-			case RTE_JOIN:
-				if (!(flags & QTW_IGNORE_JOINALIASES))
-					MUTATE(newrte->joinaliasvars, rte->joinaliasvars, List *);
-				else
-				{
-					/* else, copy join aliases as-is */
-					newrte->joinaliasvars = copyObject(rte->joinaliasvars);
-				}
-				break;
-			case RTE_FUNCTION:
-				MUTATE(newrte->functions, rte->functions, List *);
-				break;
-			case RTE_TABLEFUNC:
-				MUTATE(newrte->tablefunc, rte->tablefunc, TableFunc *);
-				break;
-			case RTE_VALUES:
-				MUTATE(newrte->values_lists, rte->values_lists, List *);
-				break;
-			case RTE_CTE:
-			case RTE_NAMEDTUPLESTORE:
-			case RTE_RESULT:
-				/* nothing to do */
-				break;
+			/* else, copy RT subqueries as-is */
+			newrte->subquery = copyObject(rte->subquery);
 		}
+
+		if (!(flags & QTW_IGNORE_JOINALIASES))
+			MUTATE(newrte->joinaliasvars, rte->joinaliasvars, List *);
+		else
+		{
+			/* else, copy join aliases as-is */
+			newrte->joinaliasvars = copyObject(rte->joinaliasvars);
+		}
+
+		MUTATE(newrte->functions, rte->functions, List *);
+		MUTATE(newrte->tablefunc, rte->tablefunc, TableFunc *);
+		MUTATE(newrte->values_lists, rte->values_lists, List *);
 		MUTATE(newrte->securityQuals, rte->securityQuals, List *);
+
+		/* we don't bother to copy eref, aliases, etc; OK? */
+
 		newrt = lappend(newrt, newrte);
 	}
 	return newrt;
-- 
2.44.0