Allow noise semicolons ending psql \sf, \ef, \sv, \ev commands.

Many psql backslash commands tolerate trailing semicolons, even
though that's not part of the official syntax.  These did not.
They tried to, by passing semicolon = true to psql_scan_slash_option,
but that function ignored this parameter in OT_WHOLE_LINE mode.
Teach it to do the right thing, and remove the now-duplicative
logic in exec_command_help.

Discussion: https://postgr.es/m/2012251.1704746912@sss.pgh.pa.us

src/bin/psql/command.c

@@ -1640,18 +1640,7 @@ exec_command_help(PsqlScanState scan_state, bool active_branch)
 	if (active_branch)
 	{
 		char	   *opt = psql_scan_slash_option(scan_state,
-												 OT_WHOLE_LINE, NULL, false);
-		size_t		len;
-
-		/* strip any trailing spaces and semicolons */
-		if (opt)
-		{
-			len = strlen(opt);
-			while (len > 0 &&
-				   (isspace((unsigned char) opt[len - 1])
-					|| opt[len - 1] == ';'))
-				opt[--len] = '\0';
-		}
+												 OT_WHOLE_LINE, NULL, true);
 
 		helpSQL(opt, pset.popt.topt.pager);
 		free(opt);
@@ -3151,6 +3140,10 @@ ignore_slash_filepipe(PsqlScanState scan_state)
  * This *MUST* be used for inactive-branch processing of any slash command
  * that takes an OT_WHOLE_LINE option.  Otherwise we might consume a different
  * amount of option text in active and inactive cases.
+ *
+ * Note: although callers might pass "semicolon" as either true or false,
+ * we need not duplicate that here, since it doesn't affect the amount of
+ * input text consumed.
  */
 static void
 ignore_slash_whole_line(PsqlScanState scan_state)

src/bin/psql/psqlscanslash.l

@@ -18,6 +18,8 @@
  */
 #include "postgres_fe.h"
 
+#include <ctype.h>
+
 #include "common.h"
 #include "psqlscanslash.h"
 
@@ -608,7 +610,7 @@ psql_scan_slash_option(PsqlScanState state,
 			/* empty arg */
 			break;
 		case xslasharg:
-			/* Strip any unquoted trailing semi-colons if requested */
+			/* Strip any unquoted trailing semicolons if requested */
 			if (semicolon)
 			{
 				while (unquoted_option_chars-- > 0 &&
@@ -640,7 +642,22 @@ psql_scan_slash_option(PsqlScanState state,
 			termPQExpBuffer(&mybuf);
 			return NULL;
 		case xslashwholeline:
-			/* always okay */
+			/*
+			 * In whole-line mode, we interpret semicolon = true as stripping
+			 * trailing whitespace as well as semicolons; this gives the
+			 * nearest equivalent to what semicolon = true does in normal
+			 * mode.  Note there's no concept of quoting in this mode.
+			 */
+			if (semicolon)
+			{
+				while (mybuf.len > 0 &&
+					   (mybuf.data[mybuf.len - 1] == ';' ||
+						(isascii((unsigned char) mybuf.data[mybuf.len - 1]) &&
+						 isspace((unsigned char) mybuf.data[mybuf.len - 1]))))
+				{
+					mybuf.data[--mybuf.len] = '\0';
+				}
+			}
 			break;
 		default:
 			/* can't get here */

src/test/regress/expected/psql.out

@@ -5323,7 +5323,7 @@ END
          LANGUAGE sql
          IMMUTABLE PARALLEL SAFE STRICT COST 1
 1       RETURN ($2 + $1)
-\sf ts_debug(text)
+\sf ts_debug(text);
 CREATE OR REPLACE FUNCTION pg_catalog.ts_debug(document text, OUT alias text, OUT description text, OUT token text, OUT dictionaries regdictionary[], OUT dictionary regdictionary, OUT lexemes text[])
  RETURNS SETOF record
  LANGUAGE sql

src/test/regress/sql/psql.sql

@@ -1315,7 +1315,7 @@ drop role regress_psql_user;
 \sf information_schema._pg_index_position
 \sf+ information_schema._pg_index_position
 \sf+ interval_pl_time
-\sf ts_debug(text)
+\sf ts_debug(text);
 \sf+ ts_debug(text)
 
 -- AUTOCOMMIT