Re: [PATCH] revision: use C99 declaration of variable in for() loop

From: Martin Ågren <martin.agren@gmail.com>
Date: Nov 15, 2021, 07:44 UTC
Message-ID: <CAN0heSpLy8c6WM1UpyEXJLfmnX=5B0eFhJwH3wqSZN15HAJGeg@mail.gmail.com>
In-Reply-To: <xmqqpmr2j5lq.fsf_-_@gitster.g>

On Mon, 15 Nov 2021 at 07:30, Junio C Hamano <gitster@pobox.com> wrote:

Show 5 quoted lines

>
> There are certain C99 features that might be nice to use in our code
> base, but we've hesitated to do so in order to avoid breaking
> compatibility with older compilers. But we don't actually know if
> people are even using pre-C99 compilers these days.

> is a long-enough time, so let's try it agin.

s/agin/again/

Show 10 quoted lines

>  void show_object_with_name(FILE *out, struct object *obj, const char *name)
>  {
> -       const char *p;
> -
>         fprintf(out, "%s ", oid_to_hex(&obj->oid));
> -       for (p = name; *p && *p != '\n'; p++)
> +       for (const char *p = name; *p && *p != '\n'; p++)
>                 fputc(*p, out);
>         fputc('\n', out);
>  }

This seems like a stable-enough function for this experiment.

Similar to 765dc16888 ("git-compat-util: always enable variadic macros", 2021-01-28), maybe we should add something like

  /*
   * This "for (const char *p = ..." is made as a first step towards
   * making use of such declarations elsewhere in our codebase.  If
   * it causes compilation problems on your platform, please report
   * it to the Git mailing list at git@vger.kernel.org.
   */

to reduce the chance of someone patching it up locally thinking that it's just a one-off.

Martin