Re: [PATCH 1/3] fix clang -Wtautological-compare with unsigned enum

From: Jonathan Nieder <jrnieder@gmail.com>
Date: Feb 3, 2013, 19:38 UTC
Message-ID: <20130203193816.GA3221@elie.Belkin>
In-Reply-To: <a9fe675ed9b34d3c15f4678ee13e90cddaa36055.1359901732.git.john@keeping.me.uk>

John Keeping wrote:

> From: Antoine Pelisse <apelisse@gmail.com>
>
> Create a GREP_HEADER_FIELD_MIN so we can check that the field value is
> sane and silent the clang warning.

Thanks.  Looks good to me.

[...]

Show 10 quoted lines

> --- a/grep.c
> +++ b/grep.c
> @@ -625,7 +625,8 @@ static struct grep_expr *prep_header_patterns(struct grep_opt *opt)
>  	for (p = opt->header_list; p; p = p->next) {
>  		if (p->token != GREP_PATTERN_HEAD)
>  			die("bug: a non-header pattern in grep header list.");
> -		if (p->field < 0 || GREP_HEADER_FIELD_MAX <= p->field)
> +		if (p->field < GREP_HEADER_FIELD_MIN ||
> +		    GREP_HEADER_FIELD_MAX <= p->field)
>  			die("bug: unknown header field %d", p->field);

I also think it would be fine to drop this test or replace it with an

	assert((unsigned) p->field < ARRAY_SIZE(header_field));

because we know the test never trips.