From: Nicolas Pitre Date: Sun, 15 Oct 2006 18:30:46 GMT Subject: Re: [PATCH] pack-objects: use of version 3 delta is now optional. Message-ID: In-Reply-To: <7vac3xzbze.fsf@assigned-by-dhcp.cox.net> On Sun, 15 Oct 2006, Junio C Hamano wrote: > Nicolas Pitre writes: > > > If anything, maybe this patch can be added before v1.4.3 is released: > >... > > This way pack v3 could be fed to GIT v1.4.3 and above whenever we add > > back pack v3 generation, and a pack converted to v2 from any v3 on the > > fly when that capability is not present. > > I think that is sensible. I also was thinking that we should > call the current one packv3 and the one with delta-base-offset > packv4. I think we should not. The pack version should be tied to incompatible pack data to prevent older GIT versions from misinterpreting newer packs. The delta block copy encoding is a perfect example of that where a bit changed meaning. The delta-base-offset case included a new object type that wasn't used before hence there is no room for confusion, and yet that new delta object could be encoded according to pack version 2 or pack version 3 which makes it orthogonal to the pack version itself. Nicolas