From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Keeping Subject: Re: [PATCH 0/2] finding the fork point from reflog entries Date: Thu, 24 Oct 2013 22:50:53 +0100 Message-ID: <20131024215053.GF10779@serenity.lan> References: <1382641884-14756-1-git-send-email-gitster@pobox.com> <20131024205434.GC10779@serenity.lan> <20131024213134.GD10779@serenity.lan> <20131024214007.GE10779@serenity.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: git@vger.kernel.org, Martin von Zweigbergk , Jonathan Nieder To: Junio C Hamano X-From: git-owner@vger.kernel.org Thu Oct 24 23:51:09 2013 Return-path: Envelope-to: gcvg-git-2@plane.gmane.org Received: from vger.kernel.org ([209.132.180.67]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1VZSo8-0002OX-Fm for gcvg-git-2@plane.gmane.org; Thu, 24 Oct 2013 23:51:08 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754354Ab3JXVvD (ORCPT ); Thu, 24 Oct 2013 17:51:03 -0400 Received: from coyote.aluminati.org ([72.9.247.114]:59594 "EHLO coyote.aluminati.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752791Ab3JXVvC (ORCPT ); Thu, 24 Oct 2013 17:51:02 -0400 Received: from localhost (localhost [127.0.0.1]) by coyote.aluminati.org (Postfix) with ESMTP id 9E3746064EA; Thu, 24 Oct 2013 22:51:01 +0100 (BST) X-Virus-Scanned: Debian amavisd-new at caracal.aluminati.org X-Spam-Flag: NO X-Spam-Score: -1 X-Spam-Level: X-Spam-Status: No, score=-1 tagged_above=-9999 required=6.31 tests=[ALL_TRUSTED=-1] autolearn=ham Received: from coyote.aluminati.org ([127.0.0.1]) by localhost (coyote.aluminati.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 5+hsJmiBJexW; Thu, 24 Oct 2013 22:51:01 +0100 (BST) Received: from serenity.lan (chimera.aluminati.org [10.0.16.60]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by coyote.aluminati.org (Postfix) with ESMTPSA id 936A3198005; Thu, 24 Oct 2013 22:50:55 +0100 (BST) Content-Disposition: inline In-Reply-To: <20131024214007.GE10779@serenity.lan> User-Agent: Mutt/1.5.22 (2013-10-16) Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: On Thu, Oct 24, 2013 at 10:40:07PM +0100, John Keeping wrote: > On Thu, Oct 24, 2013 at 10:31:35PM +0100, John Keeping wrote: > > On Thu, Oct 24, 2013 at 02:20:29PM -0700, Junio C Hamano wrote: > > > John Keeping writes: > > > > > > > On Thu, Oct 24, 2013 at 12:11:22PM -0700, Junio C Hamano wrote: > > > >> The first one is a clean-up of the code to parse command line > > > >> options to "git merge-base". Options such as "--independent", > > > >> "--is-ancestor" and "--octopus" are mutually exclusive and it is > > > >> better expressed in terms of the recently introduced OPT_CMDMODE. > > > >> > > > >> The second one implements the entire logic of the for loop we see in > > > >> "git pull --rebase" directly using get_merge_bases_many() and > > > >> postprocessing the result. > > > > > > > > Nice! I tried this in the case where the target commit happens to be > > > > the 63rd reflog entry: > > > > > > > > $ time sh -c 'for rev in $(git rev-list -g origin/master 2>/dev/null) > > > > do > > > > git merge-base --is-ancestor $rev b2edae0 && break > > > > done > > > > ' > > > > > > > > real 0m3.772s > > > > user 0m3.338s > > > > sys 0m0.440s > > > > > > > > $ time git merge-base --reflog origin/master b2edae0 > > > > > > > > real 0m0.156s > > > > user 0m0.138s > > > > sys 0m0.018s > > > > > > The real question is if the C code computes the same as the shell > > > loop. > > > > And in fact it doesn't - if you replace the "break" with "echo $rev" the > > shell version prints b2edae0... but the C version prints nothing (and > > exists with status 1). > > To clarify: the particular commit in the calls above happens to be the > oldest entry in the reflog, if I pick a newer entry then it works. > > It seems that for_each_reflog_ent isn't returning the oldest entry; > revs.nr is 62 whereas "git rev-list -g origin/master | wc -l" gives 63. The following patch on top fixes it, but I'm sure it can be done in a neater way. -- >8 -- diff --git a/builtin/merge-base.c b/builtin/merge-base.c index 7b9bc15..f6f1f14 100644 --- a/builtin/merge-base.c +++ b/builtin/merge-base.c @@ -98,7 +98,17 @@ static int collect_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1, int tz, const char *message, void *cbdata_) { struct rev_collect *revs = cbdata_; - struct commit *commit = lookup_commit(nsha1); + struct commit *commit; + + if (!revs->nr) { + commit = lookup_commit(osha1); + if (commit) { + ALLOC_GROW(revs->commit, revs->nr + 1, revs->alloc); + revs->commit[revs->nr++] = commit; + } + } + + commit = lookup_commit(nsha1); if (commit) { ALLOC_GROW(revs->commit, revs->nr + 1, revs->alloc); revs->commit[revs->nr++] = commit;