Re: Odd git overrflow bug?

From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Jul 10, 2016, 21:21 UTC
Message-ID: <CA+55aFwvZqqSkphgL+UBqfXnSGAFEzmqyH83OMGnpco3ZVZUnA@mail.gmail.com>
In-Reply-To: <CA+55aFymKO5Bi2qZ-zaiZKQAk7RxusEMJ9Y0Gw6ywdznK+TaRQ@mail.gmail.com>

On Sun, Jul 10, 2016 at 2:05 PM, Linus Torvalds <torvalds@linux-foundation.org> wrote:

>
> I'm getting "extra" being -1 in strbuf_grow(). Let me dog deeper.

"dog deeper"? My typing skills are deteriorating.

Anyway, I dug deeper, and the reason is that "tabwidth" is -1, and then

 pretty.c:1669: strbuf_add_tabexpand():

        strbuf_addchars(sb, ' ', tabwidth - (width % tabwidth));

ends up having the number be -1.

I'm not sure why it doesn't happen in current git master, because that function is the same, and the logic around expand_tabs_in_log looks similar too.

That all came from

    fe37a9c586a6 (:pretty: allow tweaking tabwidth in --expand-tabs")

and I suspect the code just needs to protect against negative or zero, rather than just zero.

Junio?

              Linus