Subject: Re: [PATCH] reflog: fix 'show' subcommand's argv

From: Junio C Hamano <[email-masked]>
Date: Mon, 28 Mar 2022 15:45:02 -0700

SZEDER Gábor <[email-masked]> writes:

> cmd_reflog() invokes parse_options() with PARSE_OPT_KEEP_ARGV0, but it
> doesn't account for the retained argv[0] before invoking
> cmd_reflog_show() to handle the 'git reflog show' subcommand.
> Consequently, cmd_reflog_show() always gets an 'argv' array starting
> with elements argv[0]="reflog" and argv[1]="show".
>
> Strip the name of the git command from the 'argv' array before passing
> it to the function handling the 'show' subcommand.
>
> There is no user-visible bug here, because cmd_reflog_show() doesn't
> have any options or parameters of its own.

These two changes cancel out as far as cmd_log_reflog() is concerned
but makes a difference inside cmd_reflog_show(), if that function
cared.

There is parse_options() call that uses argc and argv supplied by
the caller, and it is not adjusted, so it is curious why there is no
externally observable behaviour change.  But argv[0] and argv[1] are
not dashed options and because we do not say STOP_AT_NON_OPTION,
parse_options() will skip such an extra non-option argument, so is
that the reason why there is no behaviour change?

As this is an "oops, that is not quite right" fix for
ab/reflog-parse-options topic, let's queue it diretly on top of the
topic.

Thanks.

> Signed-off-by: SZEDER Gábor <[email-masked]>
> ---
>  builtin/reflog.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/builtin/reflog.c b/builtin/reflog.c
> index 6c4fe1af40..c943c2aabe 100644
> --- a/builtin/reflog.c
> +++ b/builtin/reflog.c
> @@ -225,7 +225,7 @@ static int cmd_reflog_show(int argc, const char **argv, const char *prefix)
>  		      PARSE_OPT_KEEP_DASHDASH | PARSE_OPT_KEEP_ARGV0 |
>  		      PARSE_OPT_KEEP_UNKNOWN);
>  
> -	return cmd_log_reflog(argc - 1, argv + 1, prefix);
> +	return cmd_log_reflog(argc, argv, prefix);
>  }
>  
>  static int cmd_reflog_expire(int argc, const char **argv, const char *prefix)
> @@ -425,7 +425,7 @@ int cmd_reflog(int argc, const char **argv, const char *prefix)
>  		goto log_reflog;
>  
>  	if (!strcmp(argv[1], "show"))
> -		return cmd_reflog_show(argc, argv, prefix);
> +		return cmd_reflog_show(argc - 1, argv + 1, prefix);
>  	else if (!strcmp(argv[1], "expire"))
>  		return cmd_reflog_expire(argc - 1, argv + 1, prefix);
>  	else if (!strcmp(argv[1], "delete"))