Re: [PATCH 1/2] introduce "banned function" list

From: Jeff King <peff@peff.net>
To: Junio C Hamano <gitster@pobox.com>
Cc: git@vger.kernel.org, Stefan Beller <sbeller@google.com>
Subject: Re: [PATCH 1/2] introduce "banned function" list
Date: Fri, 20 Jul 2018 13:45:24 -0400	[thread overview]
Message-ID: <20180720174524.GB22486@sigill.intra.peff.net> (raw)
In-Reply-To: <xmqqa7qmckwi.fsf@gitster-ct.c.googlers.com>

On Fri, Jul 20, 2018 at 02:32:29AM -0700, Junio C Hamano wrote:

> > Contrast this with memcpy(). This is on Microsoft's SDL banned list[1],
> > but I think it's silly for it to be. I would never add it to this list.
> 
> A tangent, but is that because they want you to use memmove()
> instead so that you do not have to worry about overlapping copies,
> perhaps?

That was my first thought, too, but nope. They recommend memcpy_s()
instead. Which in my opinion adds very little value, while missing the
most common misuse of memcpy I've seen in practice (the overlapping
thing).

Helpers like our COPY_ARRAY() are much more useful for preventing sizing
mistakes, IMHO. But again, I'd never ban memcpy. The right tool for
encouraging COPY_ARRAY() is coccinelle (because the matching is
complicated, but also because we can mechanically turn it into the right
thing, whereas a strcpy is going to require some manual reworking).

-Peff