From: Derrick Stolee <stolee@gmail.com>
Date: Mon, 03 May 2021 12:11:45 GMT
Subject: Re: [PATCH 5/5] pack-objects: clamp negative depth to 0
Message-ID: <dd080fd4-00cc-0e53-2cbd-30871c598b4d@gmail.com>
In-Reply-To: <YI1f8jKReuE3LXVH@coredump.intra.peff.net>

On 5/1/2021 10:04 AM, Jeff King wrote:
> A negative delta depth makes no sense, and the code is not prepared to
> handle it. If passed "--depth=-1" on the command line, then this line
> from break_delta_chains():
> 
> 	cur->depth = (total_depth--) % (depth + 1);
> 
> triggers a divide-by-zero. This is undefined behavior according to the C
> standard, but on POSIX systems results in SIGFPE killing the process.
> This is certainly one way to inform the use that the command was
> invalid, but it's a bit friendlier to just treat it as "don't allow any
> deltas", which we already do for --depth=0.

Makes sense to me. This whole series LGTM.

Thanks,
-Stolee