Re: [PATCH] setup_revisions(): do not access outside argv

[Jeff King <peff@peff.net>]

On Wed, May 20, 2009 at 06:58:41PM -0700, Junio C Hamano wrote:

> If a function takes (int ac, char **av), then people should be able to
> depend on the usual convention of
> 
>  (1) for any i < ac, av[i] is not NULL; and
>  (2) av[ac] is NULL.
> 
> With your patch, a broken caller's wish is simply discarded and nobody
> will notice.  Without your patch, at least you will know that the caller
> passed an inconsistent pair of ac and av to this function by seeing a
> coalmine canary segfault.
> 
> I would not mind a patch that adds an assertion that protects this
> function from broken callers, so that we can find them, but your patch
> makes me feel very uneasy.

I agree.

Having just fixed a segfault in the GIT_TRACE code caused by a
non-terminated argv generated by the alias code, I think I would prefer
that we just consistently do the NULL-termination. You are otherwise
creating a maintenance pitfall when somebody later passes the value to
unsuspecting code.

-Peff