From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-4.1 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI,SPF_HELO_NONE,SPF_NONE shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id 223681F4BD for ; Thu, 3 Oct 2019 22:16:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730329AbfJCWQm (ORCPT ); Thu, 3 Oct 2019 18:16:42 -0400 Received: from pb-smtp21.pobox.com ([173.228.157.53]:64353 "EHLO pb-smtp21.pobox.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730297AbfJCWQm (ORCPT ); Thu, 3 Oct 2019 18:16:42 -0400 Received: from pb-smtp21.pobox.com (unknown [127.0.0.1]) by pb-smtp21.pobox.com (Postfix) with ESMTP id 891318D994; Thu, 3 Oct 2019 18:16:40 -0400 (EDT) (envelope-from junio@pobox.com) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=pobox.com; h=from:to:cc :subject:references:date:in-reply-to:message-id:mime-version :content-type; s=sasl; bh=OykWiAZZkfQHPXG15hecD3U9HqQ=; b=HQQXoz Q6KjycehWZu7MQP8UYAD99S2daeOmMroTJ2uOCgysQ1VO/ieneNwEl1IHpIsKVCT miLO4k6oRXV7IOy/7G54WuMxk5FNXuhqwCgr76jZu7c0senF+vPU1ckJDXVDRcY7 ls8K2Ryfbka6LNbZ12OG3TVw4XI6pxbpfaF+M= DomainKey-Signature: a=rsa-sha1; c=nofws; d=pobox.com; h=from:to:cc :subject:references:date:in-reply-to:message-id:mime-version :content-type; q=dns; s=sasl; b=xmhEn3RUeP2LvZxulFOZWbWmn5MTZiPx rkbeda8ENOfxfCuBNKP+xdsN//g/VRhizeKFkrjnfCnZDKnvAqc/6SnFaSTjzP3k 7Xv/Ha5bWWRXk0F3uxjafS4oNiRErSJDeGCDMJQMk0KYv1CBbaXdgNIgvKUwdrIJ aojSilGGfis= Received: from pb-smtp21.sea.icgroup.com (unknown [127.0.0.1]) by pb-smtp21.pobox.com (Postfix) with ESMTP id 81F6D8D993; Thu, 3 Oct 2019 18:16:40 -0400 (EDT) (envelope-from junio@pobox.com) Received: from pobox.com (unknown [34.76.80.147]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by pb-smtp21.pobox.com (Postfix) with ESMTPSA id 37A258D990; Thu, 3 Oct 2019 18:16:37 -0400 (EDT) (envelope-from junio@pobox.com) From: Junio C Hamano To: Jeff King Cc: Denton Liu , Git Mailing List , Allan Caffee , Noam Postavsky Subject: Re: [BUG/PATCH 0/5] t4214: cleanup and demonstrate graph bug References: <20190925170902.GA11547@dentonliu-ltm.internal.salesforce.com> <20190926202326.GA16664@sigill.intra.peff.net> Date: Fri, 04 Oct 2019 07:16:34 +0900 In-Reply-To: <20190926202326.GA16664@sigill.intra.peff.net> (Jeff King's message of "Thu, 26 Sep 2019 16:23:27 -0400") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Pobox-Relay-ID: 7762B924-E62B-11E9-B146-8D86F504CC47-77302942!pb-smtp21.pobox.com Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Jeff King writes: > That works for the diagram in the code: > > | *---. > | |\ \ \ > |/ / / / > x 0 1 2 > > where one of the parent lines is collapsing back to the left. But not > for this more mundane case: > > | *-----. commit 211232bae64bcc60bbf5d1b5e5b2344c22ed767e > | |\ \ \ \ Merge: fc54a9c30c 9e30dd7c0e c4b83e618f 660265909f b28858bf65 > | | | | | | > > where we go straight down. I'm not sure I've fully grasped it, but it > feels like that distinction is the source of the off-by-one. I'm not > sure how to tell the difference here, though. I think it relies on the > next commit on the left-hand line being the same as the first parent (or > maybe any parent?). > > If I remove the use of parent_in_old_cols entirely, the merge looks > right, but the "collapsing" one is broken (and t4214 fails). > > By the way, a useful trick I stumbled on to look at the coloring across > many such merges: > > git log --graph --format=%h --color | grep -A2 -e - | less -S > > It looks like every octopus in git.git is colored wrong (because they're > the non-collapsing type). Thanks for analysing further. I wonder if new tests added by Denton's BUG/PATCH series cover both kinds? It would be good to make sure that any "fix" corrects known-broken cases while keeping the working cases still working. Thanks.