Re: How to fetch missing pack

From: Shawn O. Pearce <spearce@spearce.org>
Date: Apr 24, 2008, 06:08 UTC
Message-ID: <20080424060857.GX29771@spearce.org>
In-Reply-To: <200804240801.13674.chriscool@tuxfamily.org>

Christian Couder <chriscool@tuxfamily.org> wrote:

Show 12 quoted lines

> Le mercredi 23 avril 2008, Jörg Sommer a écrit :
> > Peter Baumann <waste.manager@gmx.de> wrote:
> > >
> > > Try using git fsck --full to check you repo. If you are missing some
> > > objects, you could just grab them from another valid repo which still
> > > has them.
> >
> > How can I exctract single objects from a pack?
> 
> Please have a look at this:
> 
> http://git.or.cz/gitwiki/GitFaq#head-ac11406480d09e2df98588e800e41b7256602074

If you know the name of the objects you are missing, you can make a temporary pack to transfer the list of objects:

	# at good repo
	#
	git pack-objects --stdout <object.list >save.pack

	# at bad repo
	#
	git index-pack --stdin <save.pack

Make object.list just one SHA-1 per line. The resulting pack is not likely to be highly compressed, as it will probably contain a non-delta version of each object, but its faster to create than calling git-cat-file for each object, and may give you a smaller pack than just copying everything as the FAQ entry recommends.

Note that you may need to do this several times; e.g. if you are missing a tree you won't know what blobs you are missing until you load the tree and run fsck --full again to parse the tree and discover the missing blobs. This iterative copying approach is what the FAQ avoids when it suggests you copy everything.

-- 
Shawn.