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=-3.2 required=3.0 tests=AWL,BAYES_00, DATE_IN_PAST_03_06,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU, FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,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 67E9C1F463 for ; Mon, 30 Sep 2019 21:55:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731577AbfI3Vzx (ORCPT ); Mon, 30 Sep 2019 17:55:53 -0400 Received: from mail-wr1-f65.google.com ([209.85.221.65]:41973 "EHLO mail-wr1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727118AbfI3Vzx (ORCPT ); Mon, 30 Sep 2019 17:55:53 -0400 Received: by mail-wr1-f65.google.com with SMTP id h7so13037503wrw.8 for ; Mon, 30 Sep 2019 14:55:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:message-id:in-reply-to:references:from:subject:fcc :content-transfer-encoding:mime-version:to:cc; bh=U4gkM8z00G+ULvSXoPJuRz3JmlhFgs9IdSuoCkDNNQc=; b=A0WFeu89jsHNv3ETUnU8OglqZxEZi1/1kjF5CcIicLaltTuZ/cYFuJCK65QlJKn8Zi uFNSLvUgjg8E5j6IdJKxlI+KB+oUPxGcx/O0aEnjFL2MIOGDP8lSKWve7//MPO+RrMDv uIZpMxzzoYxcUO+mU+6RdjF46DQ9bZNItWd15gZupLAimC9ljzOXMHb7w/FwVFDtZQdw nFxtq6TJxkuPHbPUkP9ZFk9b0Pu8uuFScve5sgphbMWO1dSoaC+jd75IBnxn2P9CY2oC hhvDFDz7+X6kfPAfaYb3jK5MY5zY0evaIhYmfz13yXP2Mu9SJhk9DwpdpjQRpym/y3nZ ViDA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:in-reply-to:references:from :subject:fcc:content-transfer-encoding:mime-version:to:cc; bh=U4gkM8z00G+ULvSXoPJuRz3JmlhFgs9IdSuoCkDNNQc=; b=n8SgIH8BnX7++qTL51R4XysIW22GEL4bTqxfNwY5WoDeLiLD7mtAZctp+fhAUt/rQj SbKXmUNYhXbcK/VkT2xqMj1AHMuPr4xVI9eR1APjYIKTUH84vOogzpfR8KJ8xiij62wE C9E+AX8obMvff7yDPVJY+Cr4+WRri6MAMYAgd4QTIzGl9rJChc0fGhGU2x14pGtACQ1j z5HkpN8EO2V2Qg04nuQWVkLu3TIYO7/c5TwHgWaao597sEKn5aqU2n9ffH15N+kE7CHD 8zdAA4CzzDcBsM35tSVGmYVo6waYdxqYiDd9IzQuZhN0yH5fDCfsff8OvR0PBkfXkwcC 8r/Q== X-Gm-Message-State: APjAAAWsA6Yl8SoH0xL3lYkUGIbcn4F8LdDgR6g+OVbTNCQmAB6hO8Z0 42YNWG5nZrC2KAUlcUFA2XVUUmag X-Google-Smtp-Source: APXvYqwERWmH1mq96YP/kRzRzJ8IeoESwTFlCerLLvLttSgclimm7kHtsQguPQRCAY1WCfXz9gS/dg== X-Received: by 2002:adf:ed88:: with SMTP id c8mr15039383wro.329.1569864116038; Mon, 30 Sep 2019 10:21:56 -0700 (PDT) Received: from [127.0.0.1] ([13.74.141.28]) by smtp.gmail.com with ESMTPSA id b12sm13369727wrt.21.2019.09.30.10.21.55 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 30 Sep 2019 10:21:55 -0700 (PDT) Date: Mon, 30 Sep 2019 10:21:55 -0700 (PDT) X-Google-Original-Date: Mon, 30 Sep 2019 17:21:52 GMT Message-Id: <442140438aa0363c53cbfe1fe07219730f042e48.1569864113.git.gitgitgadget@gmail.com> In-Reply-To: References: From: "Johannes Schindelin via GitGitGadget" Subject: [PATCH v2 2/2] diffcore_rename(): use a stable sort Fcc: Sent Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit MIME-Version: 1.0 To: git@vger.kernel.org Cc: Johannes Schindelin , Junio C Hamano , Johannes Schindelin Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org From: Johannes Schindelin During Git's rename detection, the file names are sorted. At the moment, this job is performed by `qsort()`. As that function is not guaranteed to implement a stable sort algorithm, this can lead to inconsistent and/or surprising behavior: a rename might be detected differently depending on the platform where Git was run. The `qsort()` in MS Visual C's runtime does _not_ implement a stable sort algorithm, and it even leads to an inconsistency leading to a test failure in t3030.35 "merge-recursive remembers the names of all base trees": a different code path than on Linux is taken in the rename detection of an ambiguous rename between either `e` to `a` or `a~Temporary merge branch 2_0` to `a` during a recursive merge, unexpectedly resulting in a clean merge. Let's use the stable sort provided by `git_stable_qsort()` to avoid this inconsistency. Signed-off-by: Johannes Schindelin --- diffcore-rename.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/diffcore-rename.c b/diffcore-rename.c index 9624864858..9042936aba 100644 --- a/diffcore-rename.c +++ b/diffcore-rename.c @@ -585,7 +585,7 @@ void diffcore_rename(struct diff_options *options) stop_progress(&progress); /* cost matrix sorted by most to least similar pair */ - QSORT(mx, dst_cnt * NUM_CANDIDATE_PER_DST, score_compare); + STABLE_QSORT(mx, dst_cnt * NUM_CANDIDATE_PER_DST, score_compare); rename_count += find_renames(mx, dst_cnt, minimum_score, 0); if (detect_rename == DIFF_DETECT_COPY) -- gitgitgadget