From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lachlan Patrick Subject: Re: VCS comparison table Date: Fri, 20 Oct 2006 17:47:16 +1000 Message-ID: <45387F04.5010101@research.canon.com.au> References: <9e4733910610140807p633f5660q49dd2d2111c9f5fe@mail.gmail.com> <45357411.20500@utoronto.ca> <200610180246.18758.jnareb@gmail.com> <45357CC3.4040507@utoronto.ca> <4536EC93.9050305@utoronto.ca> <87lkncev90.wl%cworth@cworth.org> <453792A8.1010700@utoronto.ca> <878xjc2qeb.wl%cworth@cworth.org> <453803E6.2060309@utoronto.ca> <87ods727pn.wl%cworth@cworth.org> <45382120.9060702@utoronto.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: git@vger.kernel.org X-From: git-owner@vger.kernel.org Fri Oct 20 09:47:24 2006 Return-path: Envelope-to: gcvg-git@gmane.org Received: from vger.kernel.org ([209.132.176.167]) by ciao.gmane.org with esmtp (Exim 4.43) id 1Gap6A-0007gE-Va for gcvg-git@gmane.org; Fri, 20 Oct 2006 09:47:23 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2992559AbWJTHrU (ORCPT ); Fri, 20 Oct 2006 03:47:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S2992560AbWJTHrU (ORCPT ); Fri, 20 Oct 2006 03:47:20 -0400 Received: from a.ns.cisra.com.au ([203.12.173.51]:44017 "EHLO ebenezer.cisra.com.au") by vger.kernel.org with ESMTP id S2992559AbWJTHrT (ORCPT ); Fri, 20 Oct 2006 03:47:19 -0400 Received: from jaroslav.research.canon.com.au (edge-aide.cisra.com.au [203.12.173.254]) by ebenezer.cisra.com.au (Postfix) with ESMTP id 74A9422243B; Fri, 20 Oct 2006 07:47:16 +0000 (UTC) Received: from [10.2.8.174] (HASPRE.research.canon.com.au [10.2.8.174]) by jaroslav.research.canon.com.au (Postfix) with ESMTP id 71EB15C041; Fri, 20 Oct 2006 07:47:16 +0000 (UTC) User-Agent: Thunderbird 1.5.0.2 (Windows/20060308) To: bazaar-ng@lists.canonical.com In-Reply-To: Sender: git-owner@vger.kernel.org Precedence: bulk X-Mailing-List: git@vger.kernel.org Archived-At: Linus Torvalds wrote: > > On Thu, 19 Oct 2006, Aaron Bentley wrote: >> I understand your argument now. It's nothing to do with numbers per se, >> and all about per-branch namespaces. Correct? > > I don't know if that is what Carl's problem is, but yes, to somebody from > the git world, it's totally insane to have the _same_ commit have ten > different names just depending on which branch is was in. > > In git-land, the name of a commit is the same in every branch. I've been following the git-vs-bzr discussion, and I'd like to ask a question (being new to both bzr and git). How does git disambiguate SHA1 hash collisions? I think git has an alternative way to name revisions (can someone please explain it in more detail, I've seen ~ mentioned only in passing in this thread). It seems to me collisions are a good argument in favour of having two independent naming schemes, so that you're not solely relying on hashes being unique. A strong argument is that a global namespace based on hashes of data is ideal because the names are generated from the data being named, and therefore are immutable. Same data => same name for that data, always and forever, which is desirable when merging named data from many sources. But the converse isn't true: one name does not necessarily map to only that data. Have I misunderstood? Is this a problem? Ta, Loki