Re: How to recovery a corrupted git repo

From: Matthieu Moy <matthieu.moy@grenoble-inp.fr>
Date: Feb 21, 2011, 14:51 UTC
Message-ID: <vpqpqql1lw6.fsf@bauges.imag.fr>
In-Reply-To: <20110221100454.GM22168@axel>

Axel Freyn <axel-freyn@gmx.de> writes:

Show 16 quoted lines

> I don't know whether there is a single git command to do it, but you can
> copy those 5 objects "by hand": in your backup, you should have a
> directory .git/objects, where you have the files
>    b7/1eb55f2dbc97dafd4a769fc61f346e69a5e0af
>    28/2035f3ae964e1e288f352c370be8edd11d3078
>    3c/20f556eecc476e3542cc522d46a62a4461fec6
>    f3/21b578edeb452358497e832815d6cae6b36886
>    6d/23f5084c975be637f7d748db82116bf84d3872
>
> It should be sufficient to just copy those files into the corrupted
> repo.
>
> However if you packed the git-files in the backup (e.g. by running "git
> gc"), those objects might be found in a pack in .git/objects/pack.
> The easiest ist probably to use git-unpack-objects to unpack the
> objects, and then copy the 5 missing objects.

There's also the brute-force approach

rsync $good_repo/.git/objects/ $bad_repo/.git/objects/ cd $bad_repo git gc

Notice the absence of --delete in the rsync command: I'm just adding new files in the $bad_repo, not deleting any (since files with identical names must have identical content).

This will result in a lot of duplicates (objects found in several packs), but "git gc" should be able to remove them.

(the notice about doing backups before also applies to my proposal ;-) )

-- 
Matthieu Moy
http://www-verimag.imag.fr/~moy/