From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu, 18 Mar 2021 23:24:22 +0000 (-0400)
Subject: Fix misuse of foreach_delete_current().
X-Git-Url: http://git.postgresql.org/gitweb/-?a=commitdiff_plain;h=1d581ce7129d7a33cd4ad27f8f246abfa1fd2db9;p=postgresql-pgindent.git

Fix misuse of foreach_delete_current().

Our coding convention requires this macro's result to be assigned
back to the original List variable.  In this usage, since the
List could not become empty, there was no actual bug --- but
some compilers warned about it.  Oversight in be45be9c3.

Discussion: https://postgr.es/m/35077b31-2d62-1e31-0e2e-ddb52d590b73@enterprisedb.com
---

diff --git a/src/backend/parser/parse_agg.c b/src/backend/parser/parse_agg.c
index 899327aaf4..1a745b742e 100644
--- a/src/backend/parser/parse_agg.c
+++ b/src/backend/parser/parse_agg.c
@@ -1844,11 +1844,11 @@ expand_grouping_sets(List *groupingSets, bool groupDistinct, int limit)
 		list_sort(result, cmp_list_len_contents_asc);
 
 		/* Finally, remove duplicates */
-		prev = list_nth_node(List, result, 0);
+		prev = linitial_node(List, result);
 		for_each_from(cell, result, 1)
 		{
 			if (equal(lfirst(cell), prev))
-				foreach_delete_current(result, cell);
+				result = foreach_delete_current(result, cell);
 			else
 				prev = lfirst(cell);
 		}