Re: [PATCH 0/4] hash.h: support choosing a separate SHA-1 for non-cryptographic uses

From: Taylor Blau <me@ttaylorr.com>
Date: Sep 5, 2024, 17:04 UTC
Message-ID: <ZtnkovOqrJNxUtez@nand.local>
In-Reply-To: <xmqq34me3uyz.fsf@gitster.g>

On Thu, Sep 05, 2024 at 09:51:00AM -0700, Junio C Hamano wrote:

Show 9 quoted lines

> Taylor Blau <me@ttaylorr.com> writes:
>
> > If so, I agree, but would note that this series does not yet switch
> > index-pack to use the non-collision detecting SHA-1 implementation when
> > available, so that would not be a prerequisite for merging this series.
>
> Hmph, I am confused.  It needs to be corrected in order to address
> collisions of the tail sum Peff raised, as no longer checked the
> tail sum with SHA1DC but with "fast" SHA-1.

Peff's mail supposes that we have already modified index-pack to use the non-collision detecting SHA-1 implementation. But this series does not do that, so I don't think we have an issue to address here.

In a hypothetical future series where we do modify index-pack to use the _FAST SHA-1 implementation, then we would need to address the issue that Peff raised first as a prerequisite.

Thanks, Taylor