From: Avery Pennarun <apenwarr@gmail.com>
Date: Fri, 26 Mar 2010 23:56:01 GMT
Subject: Re: Tree with leading '0' modes in 1.7.0.3
Message-ID: <32541b131003261656h430d77a8q753c6141297e8f86@mail.gmail.com>
In-Reply-To: <7v7hoyabiv.fsf@alter.siamese.dyndns.org>

On Fri, Mar 26, 2010 at 7:50 PM, Junio C Hamano <gitster@pobox.com> wrote:
> "Shawn O. Pearce" <spearce@spearce.org> writes:
>
>> Scott, please fix that library on GitHub.  JGit's fsck has a hard
>> failure on these malformed trees, because the leading '0' mode
>> causes the tree to come up with the wrong SHA-1 hash given its
>> logical content.  They shouldn't be created like this.
>
> What is curious is that even though 6407180 (git-fsck-cache: be stricter
> about "tree" objects, 2005-07-27) does talk about zero-padding, it appears
> that we never had a version of git that padded mode in '0' in the entire
> history of write-tree (except that "notes tree" one, but even that didn't
> escape the laboratory).

It's apparently an easy mistake to make.  bup did this for a while
until I added a 'git fsck' to its automated tests :)

The problem is that everything in git works perfectly with these
invalid file modes *except* fsck, and there's rarely a need to run
fsck, so this problem can hide for a long time.

Have fun,

Avery