From mboxrd@z Thu Jan 1 00:00:00 1970 From: "J. Bruce Fields" Subject: Re: VCS comparison table Date: Thu, 19 Oct 2006 13:14:09 -0400 Message-ID: <20061019171409.GA31671@fieldses.org> 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> <8764eg2qaa.wl%cworth@cworth.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Aaron Bentley , Linus Torvalds , Jakub Narebski , Andreas Ericsson , bazaar-ng@lists.canonical.com, git@vger.kernel.org X-From: git-owner@vger.kernel.org Thu Oct 19 19:15:56 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 1GabUB-0000qe-Qt for gcvg-git@gmane.org; Thu, 19 Oct 2006 19:15:16 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1946253AbWJSRO1 (ORCPT ); Thu, 19 Oct 2006 13:14:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1946256AbWJSRO0 (ORCPT ); Thu, 19 Oct 2006 13:14:26 -0400 Received: from mail.fieldses.org ([66.93.2.214]:43659 "EHLO pickle.fieldses.org") by vger.kernel.org with ESMTP id S1946253AbWJSROZ (ORCPT ); Thu, 19 Oct 2006 13:14:25 -0400 Received: from bfields by pickle.fieldses.org with local (Exim 4.63) (envelope-from ) id 1GabT7-0001Uc-Kt; Thu, 19 Oct 2006 13:14:09 -0400 To: Carl Worth Content-Disposition: inline In-Reply-To: <8764eg2qaa.wl%cworth@cworth.org> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: git-owner@vger.kernel.org Precedence: bulk X-Mailing-List: git@vger.kernel.org Archived-At: On Thu, Oct 19, 2006 at 10:01:33AM -0700, Carl Worth wrote: > On Thu, 19 Oct 2006 10:58:48 -0400, Aaron Bentley wrote: > > On the other hand, I think your revision identifiers are not as > > permanent as you think. > > > > In the first place, it seems fairly common in the Git community to > > rebase. This process throws away old revisions and creates new > > revisions that are morally equivalent[1]. > > Yes, rebasing does "destroy history" in one sense, (in actual fact, it > creates new commits and leaves the old ones around, which may or may > not have references to them anymore). Note that the id's are still permanent in this case; they will never (module some assumptions about the crypto) be reused. So a given id points at one and only one object, for all time; it's just that we may forget what that one object is.... > > In the second place, one must consider the "nuclear launch codes" > > scenario. > > Sure. And git does provide tools that can do this. So in this case you can certainly lose the launch codes. But you have forever granted everyone a way to determine whether a given guess at the launch codes is correct. (Again, assuming some stuff about SHA1). --b.