Re: Reproducible, corrupt packfile after fresh git-svn checkout message (gitml: message 5 of 20) (gitml: message 6 of 20)

From: Junio C Hamano <gitster@pobox.com>
Date: Aug 8, 2013, 17:38 UTC
Message-ID: <7vsiyk9j6a.fsf@alter.siamese.dyndns.org>
In-Reply-To: <87txj0i4mc.fsf@inf.ethz.ch>

Thomas Rast <trast@inf.ethz.ch> writes:

Show 26 quoted lines

> Ben Tebulin <tebulin@googlemail.com> writes:
>
>> Am 08.08.2013 16:20, schrieb Thomas Rast - trast@inf.ethz.ch:
>>> Can you try to reproduce with a version older than v1.8.3?
>>> E.g. v1.8.2.3.
>>> I'm asking because the above points at packed_object_info(), which I
>>> recently rewrote to be nonrecursive.
>>
>> It seems to run 'much better' 
>>   v1.8.2.3 : 3/10 runs do fail
>>   fb56570  : 9/10 runs do fail
>
> The good news is that this shifts the blame away from my commit ;-) as
> the problem clearly existed even before that.
>
> The bad news, of course, is that this is another hunch that turned out
> to be wrong.  I'm running out of ideas.
>
>> They always fail on a big blob (39MB) as I wrote in my first e-mail:
>>
>> ben@n179 /tmp/project.git $ ~/projects/git.git/git-show 49cdd0b21a351f3366008615d2cf8d03ca943978 | wc -c
>> error: sha1 mismatch 49cdd0b21a351f3366008615d2cf8d03ca943978
>> fatal: bad object 49cdd0b21a351f3366008615d2cf8d03ca943978
>> 0
>> ben@n179 /tmp/project.git $ ~/projects/git.git/git-show 49cdd0b21a351f3366008615d2cf8d03ca943978 | wc -c
>> 39517156

Hmm, from this, and a later one ...

Show 5 quoted lines

> Ben Tebulin <tebulin@googlemail.com> writes:
>
> I was unable to reproduce the error with the same repo and same Git
> version on a different machine (Debian Squeeze x64 on a AMD Phenom x6
> 1045T).

... I am reading that (1) the packfile and repository is basically OK, (2) reading that object sometimes fails, and (3) the symptom is not limited to fsck but anything that reads the object with parse_object(). And that symptom exists only on that single machine (I am assuming that the repository was bit-for-bit copied, not "cloned", for the purpose of testing it on the other machine). That makes me suspect something outside the control of Git (e.g. faulty memory or disk controller cable).

Are there other big blobs in the repository, and would "show | wc" fail if you attempt to read it on that machine?

Thanks all for helping to track this, by the way.