Fix misuse of foreach_delete_current().

tglsfdc · tglsfdc · commit 1d581ce7129d · 2021-03-18T19:24:22.000-04:00
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 be45be9. 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
@@ -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);
 		}

Original file line number	Diff line number	Diff line change
`@@ -1844,11 +1844,11 @@ expand_grouping_sets(List *groupingSets, bool groupDistinct, int limit)`
`1844`	`1844`	`list_sort(result, cmp_list_len_contents_asc);`
`1845`	`1845`
`1846`	`1846`	`/* Finally, remove duplicates */`
`1847`		`- prev = list_nth_node(List, result, 0);`
	`1847`	`+ prev = linitial_node(List, result);`
`1848`	`1848`	`for_each_from(cell, result, 1)`
`1849`	`1849`	`{`
`1850`	`1850`	`if (equal(lfirst(cell), prev))`
`1851`		`- foreach_delete_current(result, cell);`
	`1851`	`+ result = foreach_delete_current(result, cell);`
`1852`	`1852`	`else`
`1853`	`1853`	`prev = lfirst(cell);`
`1854`	`1854`	`}`