Correct type of front_pathkey to PathKey

tvondra · tvondra · commit 7b65862e2280 · 2022-01-23T03:53:18.000+01:00
In sort_inner_and_outer we iterate a list of PathKey elements, but the variable is declared as (List *). This mistake is benign, because we only pass the pointer to lcons() and never dereference it. This exists since ~2004, but it's confusing. So fix and backpatch to all supported branches. Backpatch-through: 10 Discussion: https://postgr.es/m/bf3a6ea1-a7d8-7211-0669-189d5c169374%40enterprisedb.com
diff --git a/src/backend/optimizer/path/joinpath.c b/src/backend/optimizer/path/joinpath.c
@@ -1258,7 +1258,7 @@ sort_inner_and_outer(PlannerInfo *root,
 
 	foreach(l, all_pathkeys)
 	{
-		List	   *front_pathkey = (List *) lfirst(l);
+		PathKey	   *front_pathkey = (PathKey *) lfirst(l);
 		List	   *cur_mergeclauses;
 		List	   *outerkeys;
 		List	   *innerkeys;

Original file line number	Diff line number	Diff line change
`@@ -1258,7 +1258,7 @@ sort_inner_and_outer(PlannerInfo *root,`
`1258`	`1258`
`1259`	`1259`	`foreach(l, all_pathkeys)`
`1260`	`1260`	`{`
`1261`		`- List front_pathkey = (List ) lfirst(l);`
	`1261`	`+ PathKey front_pathkey = (PathKey ) lfirst(l);`
`1262`	`1262`	`List *cur_mergeclauses;`
`1263`	`1263`	`List *outerkeys;`
`1264`	`1264`	`List *innerkeys;`