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=-3.1 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 2A72F1FAFB for ; Fri, 31 Mar 2017 13:52:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933231AbdCaNwC (ORCPT ); Fri, 31 Mar 2017 09:52:02 -0400 Received: from mout.kundenserver.de ([212.227.126.131]:57686 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933000AbdCaNvk (ORCPT ); Fri, 31 Mar 2017 09:51:40 -0400 Received: from localhost ([130.75.46.4]) by mrelayeu.kundenserver.de (mreue004 [212.227.15.167]) with ESMTPSA (Nemesis) id 0M0v6Z-1bzdHe2xSh-00v7K7; Fri, 31 Mar 2017 15:51:33 +0200 From: Michael J Gruber To: git@vger.kernel.org Cc: Junio C Hamano , Lars Schneider , Luke Diamand Subject: [PATCH v3 2/4] name-rev: favor describing with tags and use committer date to tiebreak Date: Fri, 31 Mar 2017 15:51:22 +0200 Message-Id: X-Mailer: git-send-email 2.12.2.739.gfc3eb97820 In-Reply-To: References: In-Reply-To: References: X-Provags-ID: V03:K0:nVPBuAP0SjMtxizzZ1aQbR/gPsff0UlywriJYID8M160qVyXQWj 9TAWaL+pzKiU9O7LsUJbnEKvdU5FgFXJN+kbVAOcbhB8JU1a3qkNqkApk1D6C+mqc+atsK8 o2Yl1ONkNjMdxu8dwhZ5S6HtEI9n30m216fzheAkH9QMk3OOm0/yD0EagZ86Cw7ffFYLiC7 GVpR2k/F5+OTMmjerjEbA== X-UI-Out-Filterresults: notjunk:1;V01:K0:Zo9KoglaQKc=:4Wt0zUXY6DXT5X4UK/yH7B 22pdct5yKekozaHSAG1M7UG+gM2oWg8Zce1X6aAmoozBxvsVQiFT+0BzlNV/lPYicM1d4Grjf W0XeQf37hrRsey7F23Dh2lLVEiIzyBb3u6OZCJCT1STVPOeWNksqrEQ7Kpd2lOt55G1RTrW9a 198GS9LXpOMv2t6bfql1gGqJ1ow0TnkGJy7QJU8+dNzBIC0Djts1T6gCVRgE3T/HrJRrDM/+D 9m9ap1AjeLUjmuQ/Kfq9POHfxb2U+vpkxobFWoxsUQry0j6K+z10yiY0nWlo7Ii8LchzGt4Ek YmaGXugmQ7TfcYpz+at23ofD7B7Gum6nVN/Pbr/AOZv1BFmwui2g6bvk9BbYzjIQA7CH7EpTh OPG1tJGD6ThJOY95Bb6rAj0JGO0dlMUu3nqs5Hiew77f6vlZ7wudtzIapw1tFfWbTVyz2Aq9y ZRbNxXntMkNWY01TE1lhrRc1mh4ulTTT4ea3uz8/3dMi3HnnM5FUToOYZ+Li6704wkb6pqB2/ oaO2Ssxl+DbS8h5hlx38xmCo0lbSypp3kfnej9tapdd3OSA0YyqlVvz54Iz+xKzpxzcpED97/ q2BJCmodcG7oxmLUmd7aEqxU7aVb5XongtBYrQB/s0NxY4ZdHWC05Tfn6L3aCOTpqmeUOWzcu vyzXLjA/OMF4lCbc9x1dnuEli6p+n4uCzgBa4QtnK+75g3kSfbPxFACt3EmwGJAq/dhs= Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org From: Junio C Hamano "git name-rev" assigned a phony "far in the future" date to tips of refs that are not pointing at tag objects, and favored names based on a ref with the oldest date. This made it almost impossible for an unannotated tags and branches to be counted as a viable base, which was especially problematic when the command is run with the "--tags" option. If an unannotated tag that points at an ancient commit and an annotated tag that points at a much newer commit reaches the commit that is being named, the old unannotated tag was ignored. Update the "taggerdate" field of the rev-name structure, which is initialized from the tip of ref, to have the committer date if the object at the tip of ref is a commit, not a tag, so that we can optionally take it into account when doing "is this name better?" comparison logic. When "name-rev" is run without the "--tags" option, the general expectation is still to name the commit based on a tag if possible, but use non-tag refs as fallback, and tiebreak among these non-tag refs by favoring names with shorter hops from the tip. The use of a phony "far in the future" date in the original code was an effective way to ensure this expectation is held: a non-tag tip gets the same "far in the future" timestamp, giving precedence to tags, and among non-tag tips, names with shorter hops are preferred over longer hops, without taking the "taggerdate" into account. As we are taking over the "taggerdate" field to store the committer date for tips with commits: (1) keep the original logic when comparing names based on two refs both of which are from refs/tags/; (2) favoring a name based on a ref in refs/tags/ hierarchy over a ref outside the hierarchy; (3) between two names based on a ref both outside refs/tags/, give precedence to a name with shorter hops and use "taggerdate" only to tie-break. A change to t4202 is a natural consequence. The test creates a commit on a branch "side" and points at it with an unannotated tag "refs/tags/side-2". The original code couldn't decide which one to favor at all, and gave a name based on a branch (simply because refs/heads/side sorts earlier than refs/tags/side-2). Because the updated logic is taught to favor refs in refs/tags/ hierarchy, the the test is updated to expect to see tags/side-2 instead. Signed-off-by: Junio C Hamano --- * I am sure others can add better heurisitics in is_better_name() for comparing names based on non-tag refs, and I do not mind people disagreeing with the logic that this patch happens to implement. This is done primarily to illustrate the value of using a separate helper function is_better_name() instead of open-coding the selection logic in name_rev() function. Signed-off-by: Michael J Gruber --- builtin/name-rev.c | 53 ++++++++++++++++++++++++++++++++++++++++++++--------- t/t4202-log.sh | 2 +- 2 files changed, 45 insertions(+), 10 deletions(-) diff --git a/builtin/name-rev.c b/builtin/name-rev.c index 7890f826ce..bf7ed015ae 100644 --- a/builtin/name-rev.c +++ b/builtin/name-rev.c @@ -13,6 +13,7 @@ typedef struct rev_name { unsigned long taggerdate; int generation; int distance; + int from_tag; } rev_name; static long cutoff = LONG_MAX; @@ -24,16 +25,43 @@ static int is_better_name(struct rev_name *name, const char *tip_name, unsigned long taggerdate, int generation, - int distance) + int distance, + int from_tag) { - return (name->taggerdate > taggerdate || - (name->taggerdate == taggerdate && - name->distance > distance)); + /* + * When comparing names based on tags, prefer names + * based on the older tag, even if it is farther away. + */ + if (from_tag && name->from_tag) + return (name->taggerdate > taggerdate || + (name->taggerdate == taggerdate && + name->distance > distance)); + + /* + * We know that at least one of them is a non-tag at this point. + * favor a tag over a non-tag. + */ + if (name->from_tag != from_tag) + return from_tag; + + /* + * We are now looking at two non-tags. Tiebreak to favor + * shorter hops. + */ + if (name->distance != distance) + return name->distance > distance; + + /* ... or tiebreak to favor older date */ + if (name->taggerdate != taggerdate) + return name->taggerdate > taggerdate; + + /* keep the current one if we cannot decide */ + return 0; } static void name_rev(struct commit *commit, const char *tip_name, unsigned long taggerdate, - int generation, int distance, + int generation, int distance, int from_tag, int deref) { struct rev_name *name = (struct rev_name *)commit->util; @@ -57,12 +85,13 @@ static void name_rev(struct commit *commit, commit->util = name; goto copy_data; } else if (is_better_name(name, tip_name, taggerdate, - generation, distance)) { + generation, distance, from_tag)) { copy_data: name->tip_name = tip_name; name->taggerdate = taggerdate; name->generation = generation; name->distance = distance; + name->from_tag = from_tag; } else return; @@ -82,10 +111,12 @@ static void name_rev(struct commit *commit, parent_number); name_rev(parents->item, new_name, taggerdate, 0, - distance + MERGE_TRAVERSAL_WEIGHT, 0); + distance + MERGE_TRAVERSAL_WEIGHT, + from_tag, 0); } else { name_rev(parents->item, tip_name, taggerdate, - generation + 1, distance + 1, 0); + generation + 1, distance + 1, + from_tag, 0); } } } @@ -216,9 +247,13 @@ static int name_ref(const char *path, const struct object_id *oid, int flags, vo } if (o && o->type == OBJ_COMMIT) { struct commit *commit = (struct commit *)o; + int from_tag = starts_with(path, "refs/tags/"); + if (taggerdate == ULONG_MAX) + taggerdate = ((struct commit *)o)->date; path = name_ref_abbrev(path, can_abbreviate_output); - name_rev(commit, xstrdup(path), taggerdate, 0, 0, deref); + name_rev(commit, xstrdup(path), taggerdate, 0, 0, + from_tag, deref); } return 0; } diff --git a/t/t4202-log.sh b/t/t4202-log.sh index f577990716..4afd8135cd 100755 --- a/t/t4202-log.sh +++ b/t/t4202-log.sh @@ -399,7 +399,7 @@ cat > expect <<\EOF | | | | Merge branch 'side' | | -| * commit side +| * commit tags/side-2 | | Author: A U Thor | | | | side-2 -- 2.12.2.739.gfc3eb97820