From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff King Subject: Re: name-rev does not show the shortest path Date: Sun, 26 Aug 2007 05:23:23 -0400 Message-ID: <20070826092323.GB30474@coredump.intra.peff.net> References: <20070823103817.GF6573@informatik.uni-freiburg.de> <20070824125230.GA12030@informatik.uni-freiburg.de> <7v6434eq9o.fsf@gitster.siamese.dyndns.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Junio C Hamano , Julian Phillips , Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= , git@vger.kernel.org To: Johannes Schindelin X-From: git-owner@vger.kernel.org Sun Aug 26 11:23:56 2007 Return-path: Envelope-to: gcvg-git@gmane.org Received: from vger.kernel.org ([209.132.176.167]) by lo.gmane.org with esmtp (Exim 4.50) id 1IPELc-0004iv-CW for gcvg-git@gmane.org; Sun, 26 Aug 2007 11:23:56 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751152AbXHZJX1 (ORCPT ); Sun, 26 Aug 2007 05:23:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750952AbXHZJX1 (ORCPT ); Sun, 26 Aug 2007 05:23:27 -0400 Received: from 66-23-211-5.clients.speedfactory.net ([66.23.211.5]:1173 "EHLO peff.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750789AbXHZJX0 (ORCPT ); Sun, 26 Aug 2007 05:23:26 -0400 Received: (qmail 19711 invoked by uid 111); 26 Aug 2007 09:23:24 -0000 Received: from coredump.intra.peff.net (HELO coredump.intra.peff.net) (10.0.0.2) by peff.net (qpsmtpd/0.32) with SMTP; Sun, 26 Aug 2007 05:23:24 -0400 Received: by coredump.intra.peff.net (sSMTP sendmail emulation); Sun, 26 Aug 2007 05:23:23 -0400 Content-Disposition: inline In-Reply-To: Sender: git-owner@vger.kernel.org Precedence: bulk X-Mailing-List: git@vger.kernel.org Archived-At: On Sat, Aug 25, 2007 at 05:04:33PM +0200, Johannes Schindelin wrote: > I briefly looked into this, and did not find out why it is behaving that > way. It _should_ pick the closer one with this code: > > } else if (name->merge_traversals > merge_traversals || > (name->merge_traversals == merge_traversals && > name->generation > generation)) { > > However, it did not even get to that code in my tests. I'll have to look > at that problem closer in a quiet moment (which I will not have for at > least another 24 hours). It does execute that code, just not for the rev in question. We hit the third part of that conditional and stop recursing on a different rev, so we only touch our "interesting" rev one time. That being said, I think this test is totally bogus. You're just looking at the generation and merge traversals from some tip. However, the tip _isn't_ the actual ref, but instead gets re-written as a string when we follow a merge. That string contains important generational information that is no longer taken into account, so you end up with things like "foo~999" with generation "3" is better than "bar~10" with generation "5". Here is a patch (below) that tracks an absolute "distance to ref" and at least names the rev in question after v2.6.22-rc1. However, because it is now preferring "distance to ref" strictly over merge traversals, it seems to generate some obscenely long names: 0567a0c022d5b343370a343121f38fd89925de55 tags/v2.6.22-rc1~1^2^2^2~11^2~13^2~8^2~1^3~5 So perhaps there is a more sane metric, but I'd have to think about it more. -Peff --- diff --git a/builtin-name-rev.c b/builtin-name-rev.c index 61eba34..c003e20 100644 --- a/builtin-name-rev.c +++ b/builtin-name-rev.c @@ -13,13 +13,14 @@ typedef struct rev_name { const char *tip_name; int merge_traversals; int generation; + int distance; } rev_name; static long cutoff = LONG_MAX; static void name_rev(struct commit *commit, const char *tip_name, int merge_traversals, int generation, - int deref) + int deref, int distance) { struct rev_name *name = (struct rev_name *)commit->util; struct commit_list *parents; @@ -45,13 +46,16 @@ static void name_rev(struct commit *commit, name = xmalloc(sizeof(rev_name)); commit->util = name; goto copy_data; - } else if (name->merge_traversals > merge_traversals || - (name->merge_traversals == merge_traversals && - name->generation > generation)) { + } else if (name->distance > distance || + (name->distance == distance && + name->merge_traversals > merge_traversals || + (name->merge_traversals == merge_traversals && + name->generation > generation))) { copy_data: name->tip_name = tip_name; name->merge_traversals = merge_traversals; name->generation = generation; + name->distance = distance; } else return; @@ -75,10 +79,10 @@ copy_data: parent_number); name_rev(parents->item, new_name, - merge_traversals + 1 , 0, 0); + merge_traversals + 1 , 0, 0, distance + 1); } else { name_rev(parents->item, tip_name, merge_traversals, - generation + 1, 0); + generation + 1, 0, distance + 1); } } } @@ -120,7 +124,7 @@ static int name_ref(const char *path, const unsigned char *sha1, int flags, void else if (!prefixcmp(path, "refs/")) path = path + 5; - name_rev(commit, xstrdup(path), 0, 0, deref); + name_rev(commit, xstrdup(path), 0, 0, deref, 0); } return 0; }