Re: [PATCH 1/6] parse-options: add precision handling for PARSE_OPT_CMDMODE

[Patrick Steinhardt <ps@pks.im>]

On Sun, Jun 29, 2025 at 01:50:31PM +0200, René Scharfe wrote:
> Build on 09705696f7 (parse-options: introduce precision handling for
> `OPTION_INTEGER`, 2025-04-17) to support value variables of different
> sizes for PARSE_OPT_CMDMODE options.  Do that by requiring their
> "precision" to be set and casting their "value" pointer accordingly.

Makes sense.

> get_value() needs to access all PARSE_OPT_CMDMODE values in addition to
> the actual value it is supposed to get to detect conflicting changes.
> Give it an example struct option pointer in cmdmode_list instead of just
> the "value" pointer to allow it to use the proper "precision".
> 
> Use optbug() in get_int_value() to report options with unsupported
> "precision" values without requiring enum opt_parsed flags, as we don't
> have them in build_cmdmode_list().  Use BUG right afterwards to abort
> for uses outside of build_cmdmode_list() by aborting immediately.

Hm. I have a bit of a hard time understanding these two paragraphs, to
be honest. Might be that my brain is still in vacation mode.

> @@ -280,19 +297,18 @@ static void build_cmdmode_list(struct parse_opt_ctx_t *ctx,
>  
>  	for (; opts->type != OPTION_END; opts++) {
>  		struct parse_opt_cmdmode_list *elem = ctx->cmdmode_list;
> -		int *value_ptr = opts->value;
>  
> -		if (!(opts->flags & PARSE_OPT_CMDMODE) || !value_ptr)
> +		if (!(opts->flags & PARSE_OPT_CMDMODE) || !opts->value)
>  			continue;
>  
> -		while (elem && elem->value_ptr != value_ptr)
> +		while (elem && elem->reference_opt->value != opts->value)
>  			elem = elem->next;

Hm. Previously we checked for the pointers to be equal, now we check for
the value to be equal. Are we sure that this is always equivalent? Can't
it ever be that two elements might have the same value?

Patrick