From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-9.2 required=3.0 tests=AWL,BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_HI,RP_MATCHES_RCVD shortcircuit=no autolearn=ham autolearn_force=no version=3.4.0 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id A3B1220FCF for ; Wed, 29 Jun 2016 21:44:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751704AbcF2Voe (ORCPT ); Wed, 29 Jun 2016 17:44:34 -0400 Received: from cloud.peff.net ([50.56.180.127]:37977 "HELO cloud.peff.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751590AbcF2Vod (ORCPT ); Wed, 29 Jun 2016 17:44:33 -0400 Received: (qmail 1327 invoked by uid 102); 29 Jun 2016 21:43:49 -0000 Received: from Unknown (HELO peff.net) (10.0.1.2) by cloud.peff.net (qpsmtpd/0.84) with SMTP; Wed, 29 Jun 2016 17:43:49 -0400 Received: (qmail 30991 invoked by uid 107); 29 Jun 2016 21:44:03 -0000 Received: from sigill.intra.peff.net (HELO sigill.intra.peff.net) (10.0.0.7) by peff.net (qpsmtpd/0.84) with SMTP; Wed, 29 Jun 2016 17:44:03 -0400 Received: by sigill.intra.peff.net (sSMTP sendmail emulation); Wed, 29 Jun 2016 17:43:44 -0400 Date: Wed, 29 Jun 2016 17:43:44 -0400 From: Jeff King To: Stefan Beller Cc: Junio C Hamano , Linus Torvalds , Marc Strapetz , Git Mailing List Subject: Re: topological index field for commit objects Message-ID: <20160629214343.GA3682@sigill.intra.peff.net> References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On Wed, Jun 29, 2016 at 02:37:17PM -0700, Stefan Beller wrote: > On Wed, Jun 29, 2016 at 1:54 PM, Stefan Beller wrote: > > Chances are that the 10 years of history may be correct time wise as long > > as people don't introduce a bad date malevolently. > > > > To answer my own speculation: > Even git.git violates the timing property, so there is no hope to find > many projects > to have "parents committer date < committer date" It's expected and reasonable for there to be some skew. People's clocks aren't all perfectly synced. The question is one of how _much_ skew you're willing to tolerate (and any algorithms obviously need to allow that much, too). In some places we allow 24 hours of skew between any two commits. In others we allow up to 5 skewed commits in a row. That may not be enough in general, though. E.g.: > 619a644d6daef56d70aeca85514e2d281eb483a5 This one is a 3-day skew. -Peff