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

[Harald van Dijk]

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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>> http://lists.busybox.net/mailman/listinfo/busybox
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