Correct type of front_pathkey to PathKey

tvondra · tvondra · commit 93854d5b1bf3 · 2022-01-23T03:59:50.000+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
@@ -996,7 +996,7 @@ 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
`@@ -996,7 +996,7 @@ sort_inner_and_outer(PlannerInfo *root,`
`996`	`996`
`997`	`997`	`foreach(l, all_pathkeys)`
`998`	`998`	`{`
`999`		`- List front_pathkey = (List ) lfirst(l);`
	`999`	`+ PathKey front_pathkey = (PathKey ) lfirst(l);`
`1000`	`1000`	`List *cur_mergeclauses;`
`1001`	`1001`	`List *outerkeys;`
`1002`	`1002`	`List *innerkeys;`