From mboxrd@z Thu Jan 1 00:00:00 1970 From: Junio C Hamano Subject: Re: git and time Date: Thu, 28 Sep 2006 10:28:45 -0700 Message-ID: <7vodszuche.fsf@assigned-by-dhcp.cox.net> References: <20060928165509.77413.qmail@web51001.mail.yahoo.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: git@vger.kernel.org, Matthew L Foster X-From: git-owner@vger.kernel.org Thu Sep 28 19:29:29 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 1GSzgz-0003be-LS for gcvg-git@gmane.org; Thu, 28 Sep 2006 19:29:04 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751330AbWI1R2s (ORCPT ); Thu, 28 Sep 2006 13:28:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751957AbWI1R2r (ORCPT ); Thu, 28 Sep 2006 13:28:47 -0400 Received: from fed1rmmtao12.cox.net ([68.230.241.27]:32509 "EHLO fed1rmmtao12.cox.net") by vger.kernel.org with ESMTP id S1751330AbWI1R2q (ORCPT ); Thu, 28 Sep 2006 13:28:46 -0400 Received: from fed1rmimpo02.cox.net ([70.169.32.72]) by fed1rmmtao12.cox.net (InterMail vM.6.01.06.01 201-2131-130-101-20060113) with ESMTP id <20060928172846.VQA26416.fed1rmmtao12.cox.net@fed1rmimpo02.cox.net>; Thu, 28 Sep 2006 13:28:46 -0400 Received: from assigned-by-dhcp.cox.net ([68.5.247.80]) by fed1rmimpo02.cox.net with bizsmtp id TtUo1V0061kojtg0000000 Thu, 28 Sep 2006 13:28:48 -0400 To: Linus Torvalds In-Reply-To: (Linus Torvalds's message of "Thu, 28 Sep 2006 10:11:01 -0700 (PDT)") User-Agent: Gnus/5.110006 (No Gnus v0.6) Emacs/21.4 (gnu/linux) Sender: git-owner@vger.kernel.org Precedence: bulk X-Mailing-List: git@vger.kernel.org Archived-At: Linus Torvalds writes: > On Thu, 28 Sep 2006, Matthew L Foster wrote: >> >> I am not saying git should "police any one else's clocks", I am saying git should be designed or >> configured in such a way, using local time, that it obviates the current reliance on everyone >> else's clock being set correctly. > > Matt! > > THERE IS NO SUCH RELIANCE! NONE. > > Trust me. When we say that git ignores time, WE MEAN IT. Git does not rely > on time, git does not use time, git does not CARE! > > Please stop looking at gitweb _immediately_. If you think time has some > meaning for git, stop. It doesn't. We've told you over and over and over > again that there is absolutely _zero_ reliance on everybody else's clock > being set correctly. The damn clock could go _backwards_, or make huge > jumping purple leaps of imagination, and git wouldn't care. I think Matthew means (by "relying") that everybody's clock must be set correctly in order for us to show the commits in gitweb or rev-list output so that their timestamps are monotonically decreasing (because we list things from newer to older). I sympathise. We order things by causality (i.e. ancestry order), but that unfortunately (!!) happens to match timestamp order for simple history made on a single machine. This can easily lead to such a misunderstanding that we are somehow trying to show things in linear time order, hence we subscribe to the notion of global, uniform and monotonic time. Of course, we don't.