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([2001:4898:a800:1010:ee45:d3f7:2db7:a1e2]) by smtp.gmail.com with ESMTPSA id x6sm1882451qkh.20.2020.01.08.12.05.50 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 08 Jan 2020 12:05:51 -0800 (PST) Subject: Re: [PATCH 0/2] Graph horizontal fix To: Junio C Hamano , Derrick Stolee via GitGitGadget Cc: git@vger.kernel.org, peff@peff.net, jcoglan@gmail.com, Derrick Stolee References: From: Derrick Stolee Message-ID: Date: Wed, 8 Jan 2020 15:05:50 -0500 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:72.0) Gecko/20100101 Thunderbird/72.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On 1/8/2020 1:06 PM, Junio C Hamano wrote: > "Derrick Stolee via GitGitGadget" writes: > >> This depends on ds/graph-assert-fix. >> >> This is a non-critical (not needed for v2.25.0) response to the previous >> discussions [1] [2]. >> >> While working to resolve the fix for the assert() bug, I noticed this >> regression when multiple edges wanted to collapse with horizontal lines. It >> takes a reasonably large graph, but real projects are likely to demonstrate >> this behavior. >> >> I arranged the series into two patches: 1. the (failing) test, and 2. the >> fix. >> >> The fix commit includes some details about why the change to compress merge >> commits caused this regression, and why I feel relatively confident that >> this is a correct resolution. > > I am not sure if this is "fix" of "bug" in that what is shown > without 2/2 (iow, "before this change" in the description of 2/2) is > "wrong" per-se---it is just that it leaves room to be made even more > compact. It still is an improvement, of course, though. I guess I was incomplete in my first example. The full horizontal behavior before 0f0f389f was | | | | | | *-. | | | | | | |\ \ | |_|_|_|_|/ | | |/| | | | | / / | | |_|_|_|/ / | |/| | | | / | | | |_|_|/ | | |/| | | and 0f0f389f added a compact merge commit, but lost two horizontal lines. | | | | | | * | |_|_|_|_|/|\ |/| | | | |/ / | | | | |/| / | | | |/| |/ | | |/| |/| | |/| |/| | | | |/| | | This change brings the horizontal lines back. | | | | | | * | |_|_|_|_|/|\ |/| | | | |/ / | | |_|_|/| / | |/| | | |/ | | | |_|/| | | |/| | | Whether this qualifies as a "bug" is debatable, for sure. That's why I believe this change is below the bar for the release candidate. Thanks, -Stolee