Fix optind handling inconsistency in getopt_long() for missing argument

[Japin Li]

Hi, hackers

I noticed an inconsistency in how optind is handled when a required argument
is missing.

For short options, the current code handles the BADARG case as follows:

        else if (argc <= ++optind)
        {                       /* no arg */
            place = EMSG;
            if (*optstring == ':')
                return BADARG;
            if (opterr)
                fprintf(stderr,
                        "%s: option requires an argument -- %c\n",
                        argv[0], optopt);
            return BADCH;
        }

Here, place is set to EMSG and optind is incremented before returning BADARG.
However, for long options, the same logic currently sets place = EMSG and
increments optind after returning BADARG.

        else
        {
            if (optstring[0] == ':')
                return BADARG;    <-- here, return before increasing optind

            if (opterr && has_arg == required_argument)
                fprintf(stderr,
                        "%s: option requires an argument -- %s\n",
                        argv[0], place);

            place = EMSG;
            optind++;

            if (has_arg == required_argument)
                return BADCH;
            optarg = NULL;
        }

The attached patch moves the place = EMSG and optind++ assignments to the
beginning of the long‑option error block, aligning the behavior with that of
short options.

Any thought?

-- 
Regards,
Japin Li
ChengDu WenWu Information Technology Co., Ltd.


>From 22914a78ccdfb1d05a907ef43474cb6253f62293 Mon Sep 17 00:00:00 2001
From: Japin Li <japi...@hotmail.com>
Date: Tue, 21 Jul 2026 17:49:02 +0800
Subject: [PATCH v1] Fix optind handling inconsistency in getopt_long() for
 missing argument

Move optind++ and place = EMSG before the BADARG return in the long option
path to match short option behavior and ensure consistent state.
---
 src/port/getopt_long.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/port/getopt_long.c b/src/port/getopt_long.c
index 20953db9db1..a488a647889 100644
--- a/src/port/getopt_long.c
+++ b/src/port/getopt_long.c
@@ -145,6 +145,9 @@ retry:
 						}
 						else
 						{
+							place = EMSG;
+							optind++;
+
 							if (optstring[0] == ':')
 								return BADARG;
 
@@ -153,9 +156,6 @@ retry:
 										"%s: option requires an argument -- %s\n",
 										argv[0], place);
 
-							place = EMSG;
-							optind++;
-
 							if (has_arg == required_argument)
 								return BADCH;
 							optarg = NULL;
-- 
2.53.0