From: Stefan Monnier <monnier@iro.umontreal.ca>
To: Jeff King <peff@peff.net>
Cc: git@vger.kernel.org
Subject: Re: `git gc` says "unable to read" but `git fsck` happy
Date: Thu, 30 Mar 2023 09:01:39 -0400 [thread overview]
Message-ID: <jwvfs9mz9n7.fsf-monnier+Inbox@gnu.org> (raw)
In-Reply-To: <20230329233735.GD2314218@coredump.intra.peff.net> (Jeff King's message of "Wed, 29 Mar 2023 19:37:35 -0400")
>> How come it can't read `f5e44b38fc8f7e15e5e6718090d05b09912254fa` during
>> "repack" while `git fsck` says everything is fine?
>
> Do you use separate worktrees?
Very much so, indeed!
> It sounds like it might be similar to this case:
>
> https://lore.kernel.org/git/c6246ed5-bffc-7af9-1540-4e2071eff5dc@kdbg.org/
That's sounds exactly right. I was actually preparing to file
a separate bug report because of a similar problem I had identified
where a worktree's `index` caused a similar problem (`git fsck` happy
but `git gc` fails) except it was found much earlier in `git gc`,
causing a "bad object" error almost right away.
> If so, there are patches in the current "master" (but not in a released
> version yet) that fix fsck to detect this.
Good, thanks.
>> More importantly: how do I diagnose this further and fix it?
>
> If it is the same problem (which would be a blob or maybe cached tree
> missing in one of the worktree's index files), then probably you'd
> either:
>
> 1. Accept the loss and blow away that worktree's index file (or
> perhaps even the whole worktree, and just recreate it).
Hmm... the problem is "that": I have about a hundred worktrees for
this repository.
But yes, I can just throw away all those `index` files, I guess.
> (assuming that the file itself is still hanging around).
> The original corruption bug itself (gc not taking into account worktree
> index files) has been fixed for a while, so the theory is that this can
> be lingering corruption from a repack by an older version of Git. But if
> you have evidence to the contrary, we'd like to hear that, too. ;)
My suspicion is that the origin of the broken state is elsewhere (maybe
a power failure?) because the problem appeared "simultaneously" (a few
days apart, really) for two different repositories.
> I don't think --aggressive would help at all. In theory --prune=now
> might, but I think even that won't help if the problem is that the
> object is referenced in an index file.
Indeed, I had also tried `--prune=now` and it did not help.
Thanks,
Stefan
next prev parent reply other threads:[~2023-03-30 13:02 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-29 22:05 `git gc` says "unable to read" but `git fsck` happy Stefan Monnier
2023-03-29 23:37 ` Jeff King
2023-03-30 13:01 ` Stefan Monnier [this message]
2023-03-30 18:17 ` Jeff King
2023-06-01 12:04 ` Andreas Schwab
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