Fix case sensitivity in psql's tab completion for GUC names.

Input for these should be case-insensitive, but was not completely
so.  Comparing to the similar queries for timezone names, I realized
that we'd missed forcing the comparison pattern to lower-case.
With that, it behaves as I expect.

While here, flatten the sub-selects in these queries; I don't
find that those add any readability.

Discussion: https://postgr.es/m/3369130.1649348542@sss.pgh.pa.us

diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 10e8dbc9b1feadb1b6f082e05bd626cd8101e605..588c0841fee1554d0861cea94f45a5d14bf1f046 100644 (file)
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -1006,24 +1006,18 @@ static const SchemaQuery Query_for_trigger_of_table = {
 
 /* Use COMPLETE_WITH_QUERY_VERBATIM with these queries for GUC names: */
 #define Query_for_list_of_alter_system_set_vars \
-"SELECT name FROM "\
-" (SELECT pg_catalog.lower(name) AS name FROM pg_catalog.pg_settings "\
-"  WHERE context != 'internal' "\
-" ) ss "\
-" WHERE name LIKE '%s'"
+"SELECT pg_catalog.lower(name) FROM pg_catalog.pg_settings "\
+" WHERE context != 'internal' "\
+"   AND pg_catalog.lower(name) LIKE pg_catalog.lower('%s')"
 
 #define Query_for_list_of_set_vars \
-"SELECT name FROM "\
-" (SELECT pg_catalog.lower(name) AS name FROM pg_catalog.pg_settings "\
-"  WHERE context IN ('user', 'superuser') "\
-" ) ss "\
-" WHERE name LIKE '%s'"
+"SELECT pg_catalog.lower(name) FROM pg_catalog.pg_settings "\
+" WHERE context IN ('user', 'superuser') "\
+"   AND pg_catalog.lower(name) LIKE pg_catalog.lower('%s')"
 
 #define Query_for_list_of_show_vars \
-"SELECT name FROM "\
-" (SELECT pg_catalog.lower(name) AS name FROM pg_catalog.pg_settings "\
-" ) ss "\
-" WHERE name LIKE '%s'"
+"SELECT pg_catalog.lower(name) FROM pg_catalog.pg_settings "\
+" WHERE pg_catalog.lower(name) LIKE pg_catalog.lower('%s')"
 
 #define Query_for_list_of_roles \
 " SELECT rolname "\