From: david@lang.hm Date: Fri, 22 Jul 2011 18:02:07 GMT Subject: Re: Git commit generation numbers Message-ID: In-Reply-To: <201107221418.52414.jnareb@gmail.com> On Fri, 22 Jul 2011, Jakub Narebski wrote: >> Yes, the cache validity/invalidation criteria are the tricky bit. >> Honestly, this is where the code gets ugly, not computing and storing >> the generation numbers. > > BTW. with storing generation number in commit header there is a problem > what would old version of git, one which does not understand said header, > do during rebase. Would it strip unknown headers, or would it copy > generation number verbatim - which means that it can be incorrect? Linus has already pointed out that this is safe. old versions won't create generation numbers, but they will ignore them if they exist. Since commits are not modified after they are created, the old versions don't copy or modify them. David Lang