[PATCH] libbb: make '--help' handling more consistent

[Denys Vlasenko]

Fixed in git

On Thu, Aug 25, 2022 at 7:26 AM Harald van Dijk <harald at gigawatt.nl> wrote:
>
> This breaks the [ command. Previously, [ --help would show help, which
> is okay as an extension since it is not valid with the standard [
> command. This change makes [ --help ] also show help, when it is
> required to just check that the string --help is not empty.
>
> On 22/08/2022 13:07, Denys Vlasenko wrote:
> > Applied, thank you
> >
> > On Sun, May 1, 2022 at 10:46 AM Ron Yorston <rmy at pobox.com> wrote:
> >>
> >> Running an applet with '--help' as its only argument is treated
> >> as a special case.  If additional arguments follow '--help' the
> >> behaviour is inconsistent:
> >>
> >> - applets which call single_argv() print help and do nothing else;
> >>
> >> - applets which call getopt() report "unrecognized option '--help'"
> >>    and print help anyway;
> >>
> >> - expr says "expr: syntax error" and doesn't print help;
> >>
> >> - printenv silently ignores '--help', prints any other variables
> >>    and doesn't print help;
> >>
> >> - realpath says "--help: No such file or directory", prints the path
> >>    of any other files and doesn't print help.
> >>
> >> If the first argument is '--help' ignore any other arguments and print
> >> help.  This is more consistent and most likely what the user wanted.
> >>
> >> See also commit 6bdfbc4cb (libbb: fix '--help' handling in
> >> FEATURE_SH_NOFORK=y).
> >>
> >> function                                             old     new   delta
> >> show_usage_if_dash_dash_help                          75      69      -6
> >> ------------------------------------------------------------------------------
> >> (add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-6)               Total: -6 bytes
> >>
> >> Signed-off-by: Ron Yorston <rmy at pobox.com>
> >> ---
> >>   libbb/appletlib.c | 5 ++---
> >>   1 file changed, 2 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/libbb/appletlib.c b/libbb/appletlib.c
> >> index 841b3b873..d56b5b409 100644
> >> --- a/libbb/appletlib.c
> >> +++ b/libbb/appletlib.c
> >> @@ -258,7 +258,6 @@ void lbb_prepare(const char *applet
> >>          /* Redundant for busybox (run_applet_and_exit covers that case)
> >>           * but needed for "individual applet" mode */
> >>          if (argv[1]
> >> -        && !argv[2]
> >>           && strcmp(argv[1], "--help") == 0
> >>           && !is_prefixed_with(applet, "busybox")
> >>          ) {
> >> @@ -940,8 +939,8 @@ void FAST_FUNC show_usage_if_dash_dash_help(int applet_no, char **argv)
> >>           && applet_no != APPLET_NO_echo
> >>   #  endif
> >>          ) {
> >> -               if (argv[1] && !argv[2] && strcmp(argv[1], "--help") == 0) {
> >> -                       /* Make "foo --help" exit with 0: */
> >> +               if (argv[1] && strcmp(argv[1], "--help") == 0) {
> >> +                       /* Make "foo --help [...]" exit with 0: */
> >>                          xfunc_error_retval = 0;
> >>                          bb_show_usage();
> >>                  }
> >> --
> >> 2.35.1
> >>
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> >