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-Status: No, score=-3.8 required=3.0 tests=AWL,BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by dcvr.yhbt.net (Postfix) with ESMTP id 6B29B1F4B4 for ; Tue, 12 Jan 2021 14:20:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728481AbhALOST (ORCPT ); Tue, 12 Jan 2021 09:18:19 -0500 Received: from cloud.peff.net ([104.130.231.41]:53452 "EHLO cloud.peff.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725372AbhALOSS (ORCPT ); Tue, 12 Jan 2021 09:18:18 -0500 Received: (qmail 10595 invoked by uid 109); 12 Jan 2021 14:17:38 -0000 Received: from Unknown (HELO peff.net) (10.0.1.2) by cloud.peff.net (qpsmtpd/0.94) with ESMTP; Tue, 12 Jan 2021 14:17:38 +0000 Authentication-Results: cloud.peff.net; auth=none Received: (qmail 14840 invoked by uid 111); 12 Jan 2021 14:17:37 -0000 Received: from coredump.intra.peff.net (HELO sigill.intra.peff.net) (10.0.0.2) by peff.net (qpsmtpd/0.94) with (TLS_AES_256_GCM_SHA384 encrypted) ESMTPS; Tue, 12 Jan 2021 09:17:37 -0500 Authentication-Results: peff.net; auth=none Date: Tue, 12 Jan 2021 09:17:37 -0500 From: Jeff King To: Arnaud Morin Cc: git@vger.kernel.org, Kevin Willford Subject: Re: rev-list with multiple commits sharing same patch-id Message-ID: References: <20210109162440.GM31701@sync> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20210109162440.GM31701@sync> Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On Sat, Jan 09, 2021 at 04:24:40PM +0000, Arnaud Morin wrote: > After digging a little bit, the thing is that this commit is having the > following patch-id: > $ git show dbf86d8aafc897a25a3093139b4237a62395041e | git patch-id > 20f4ace68e80a751b07d78a27c94e83d6c5314bc dbf86d8aafc897a25a3093139b4237a62395041e > > Which is also already existing in an other commit: > $ for c in $(git rev-list HEAD) ; do git show $c |git patch-id |grep 20f4ace68e80a751b07d78a27c94e83d6c5314bc; done > 20f4ace68e80a751b07d78a27c94e83d6c5314bc dbf86d8aafc897a25a3093139b4237a62395041e > 20f4ace68e80a751b07d78a27c94e83d6c5314bc 8969d3fa9159730fd3b23199873bfb26e3d20027 A slight nit first. Those two commits have the same patch-id, but in your graph they are on the same branch ("master", not "B"): > The commits in B are cherry-picked from master. > Here is the graph: > $ git log --graph --oneline --all > * ae2e3c4 (origin/B, B) remove line2 and add line4 (bis) > * a7a0339 remove line4 > * caa4aad restore line2 > * d7dc596 remove line2 add line4 > * 44bcfd4 add line3 > * e372641 b > | * dbf86d8 (HEAD -> master, origin/master) remove line2 and add line4 (bis) > | * 4017282 remove line4 > | * 0f2a449 restore line2 > | * 8969d3f remove line2 add line4 > | * e73b420 add line3 > | * fe5a75a b > |/ > * 6192505 a > * b4089e1 init And --cherry-pick is only looking for matches between the two sides of the symmetric difference. However, I think that patch-id does exist on the other side (it appears again twice in fact, which is not surprising): $ git rev-list --all | git diff-tree --stdin -p | git patch-id | grep 20f4ace68e80 20f4ace68e80a751b07d78a27c94e83d6c5314bc ae2e3c4754f53440cc4612d35f80d795a695c862 20f4ace68e80a751b07d78a27c94e83d6c5314bc dbf86d8aafc897a25a3093139b4237a62395041e 20f4ace68e80a751b07d78a27c94e83d6c5314bc d7dc596fcc34662cba35363febc846bfcab1e4be 20f4ace68e80a751b07d78a27c94e83d6c5314bc 8969d3fa9159730fd3b23199873bfb26e3d20027 So the entries should be suppressed from both sides. It looks like this was broken in v2.10.0, via dfb7a1b4d0 (patch-ids: stop using a hand-rolled hashmap implementation, 2016-07-29). I think the issue is that it is allowing duplicate entries in the hashmap. The algorithm is something like: - iterate over left-hand commits, inserting patch-id for each into hashmap - iterate over right-hand commits, seeing if any are present in hashmap. If so, we exclude the commit _and_ mark the patch-id as "seen" - iterate again over left-hand commits, omitting any whose patch-ids are marked as "seen" So if two commits on the left-hand side have the same patch-id, if we insert two entries into the hashmap, then only one of them is going to get its "seen" flag marked in the middle step. -Peff