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From: "Greg Hurrell" <greg@hurrell.net>
To: git@vger.kernel.org
Cc: "Phillip Wood" <phillip.wood@dunelm.org.uk>
Subject: Re: Bad behavior in xhistogram.c in the face of hash collisions?
Date: Fri, 26 Aug 2022 17:53:28 +0200	[thread overview]
Message-ID: <70e68b28-73fa-4d16-a135-cbb03ea09d35@betaapp.fastmail.com> (raw)
In-Reply-To: <4e0eff48-4a3e-4f0e-9ed2-d01ec38442a5@www.fastmail.com>

On Mon, Aug 16, 2021, at 2:40 PM, Greg Hurrell wrote:
> 
> I think I may have found a bug in the histogram diff algorithm that
> manifests when there is a hash collision.  This behavior seems to exist
> in the JGit implimentation (https://git.io/J0Ud8) too, and was brought
> across with the port-to-C in 8c912eea94a2.

Thought I had better bump the thread as I did a fire-and-forget on it
a year ago and never followed up because I wasn't super confident
about my findings.

I'd be interested in corroboration of my analysis, to see whether there
really is a bug there. Not quoting my entire email here so as to keep
things brief, but the original can be seen at:

https://public-inbox.org/git/4e0eff48-4a3e-4f0e-9ed2-d01ec38442a5@www.fastmail.com/

(Phillip, CC'ing you for an opinion because I see you have made a few
changes to xdiff/xhistogram.c relatively recently.)

Best wishes,
Greg

      reply	other threads:[~2022-08-26 15:53 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-16 12:40 Bad behavior in xhistogram.c in the face of hash collisions? Greg Hurrell
2022-08-26 15:53 ` Greg Hurrell [this message]

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