Subject: Re: [PATCH 6/6] parse-options: add precision handling for OPTION_COUNTUP

From: Patrick Steinhardt <[email-masked]>
Date: Tue, 1 Jul 2025 12:55:25 +0200

On Sun, Jun 29, 2025 at 01:51:36PM +0200, René Scharfe wrote:
> diff --git a/parse-options.c b/parse-options.c
> index 0dc9b0324a..0dd08a3a77 100644
> --- a/parse-options.c
> +++ b/parse-options.c
> @@ -166,10 +166,22 @@ static enum parse_opt_result do_get_value(struct parse_opt_ctx_t *p,
>  	}
>  
>  	case OPTION_COUNTUP:
> -		if (*(int *)opt->value < 0)
> -			*(int *)opt->value = 0;
> -		*(int *)opt->value = unset ? 0 : *(int *)opt->value + 1;
> -		return 0;
> +	{
> +		size_t bits = CHAR_BIT * opt->precision;
> +		intmax_t upper_bound = INTMAX_MAX >> (bitsizeof(intmax_t) - bits);
> +		intmax_t value = get_int_value(opt);
> +
> +		if (value < 0)
> +			value = 0;
> +		if (unset)
> +			value = 0;
> +		else if (value < upper_bound)
> +			value++;
> +		else
> +			return error(_("value for %s exceeds %"PRIdMAX),
> +				     optname(opt, flags), upper_bound);
> +		return set_int_value(opt, flags, value);
> +	}
>  
>  	case OPTION_SET_INT:
>  		return set_int_value(opt, flags, unset ? 0 : opt->defval);
> @@ -630,10 +642,10 @@ static void parse_options_check(const struct option *opts)
>  		case OPTION_BIT:
>  		case OPTION_NEGBIT:
>  		case OPTION_BITOP:
> +		case OPTION_COUNTUP:
>  			if (!signed_int_fits(opts->defval, opts->precision))
>  				optbug(opts, "has invalid defval");
>  			/* fallthru */
> -		case OPTION_COUNTUP:
>  		case OPTION_NUMBER:
>  			if ((opts->flags & PARSE_OPT_OPTARG) ||
>  			    !(opts->flags & PARSE_OPT_NOARG))
> diff --git a/parse-options.h b/parse-options.h
> index 8bdf469ae9..312045604d 100644
> --- a/parse-options.h
> +++ b/parse-options.h
> @@ -183,6 +183,7 @@ struct option {
>  	.short_name = (s), \
>  	.long_name = (l), \
>  	.value = (v), \

It's a bit surprising that `COUNTUP` accepts a signed integer, so should
we maybe add `BARF_UNLESS_SIGNED(*(v))` here?

> +	.precision = sizeof(*v), \
>  	.help = (h), \
>  	.flags = PARSE_OPT_NOARG|(f), \
>  }

Patrick