Re: [PATCH/RFC] Allow writing loose objects that are corrupted in a pack file

From: Nicolas Pitre <nico@cam.org>
Date: Jan 7, 2009, 02:09 UTC
Message-ID: <alpine.LFD.2.00.0901062059230.26118@xanadu.home>
In-Reply-To: <1231292360.8870.61.camel@starfruit>

On Tue, 6 Jan 2009, R. Tyler Ballance wrote:

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> On Tue, 2009-01-06 at 20:25 -0500, Nicolas Pitre wrote:
> > On Tue, 6 Jan 2009, R. Tyler Ballance wrote:
> > 
> > > On Tue, 2008-12-09 at 09:36 +0100, Jan Krüger wrote:
> > > > For fixing a corrupted repository by using backup copies of individual
> > > > files, allow write_sha1_file() to write loose files even if the object
> > > > already exists in a pack file, but only if the existing entry is marked
> > > > as corrupted.
> > > 
> > > I figured I'd reply to this again, since the issue cropped up again.
> > > 
> > > We started experiencing *large* numbers of corruptions like the ones
> > > that started the thread (one developer was receiving them once or twice
> > > a day) with v1.6.0.4
> > > 
> > > We went ahead and upgraded to a custom build of v1.6.1 with Jan's patch
> > > (below) and the issues /seem/ to have resolved themselves. I'm not
> > > certain whether Jan's patch was really responsible, or if there was
> > > another issue that caused this to correct itself in v1.6.1. 
> 
> I'll back the patch out and redeploy, it's worth mentioning that a
> coworker of mine just got the issue as well (on 1.6.1). He was able to
> `git pull` and the error went away, but I doubt that it "magically fixed
> itself"

Please describe the "issue", ideally with transcripts of error messages, etc. Normally a simple pull operation should not provide any "fix" for corruptions.

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> I highly doubt this, I've got the issue appearing on at least 7
> different development boxes (not workstations, 2U quad-core ECC RAM, etc
> machines), while that doesn't mean that they all don't have issues, the
> probability of them *all* having disk issues, and it somehow only
> manifesting itself with Git usage, is low ;)

Agreed.

> I've tarred one of the repositories that had it in a reproducible state

That is wonderful.

> so I can create a build and extract the tar and run against that to
> verify any patches anybody might have, but unfortunately at 7GB of
> company code and assets, I can't exactly share ;)

First step is to understand what is going on. Only then could reliable patches be made.

Nicolas