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=-4.0 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI 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 F10301F45F for ; Wed, 8 May 2019 00:13:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726628AbfEHANZ (ORCPT ); Tue, 7 May 2019 20:13:25 -0400 Received: from mail-wr1-f66.google.com ([209.85.221.66]:36696 "EHLO mail-wr1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726371AbfEHANY (ORCPT ); Tue, 7 May 2019 20:13:24 -0400 Received: by mail-wr1-f66.google.com with SMTP id o4so24678103wra.3 for ; Tue, 07 May 2019 17:13:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=LakZ+D3Q2eUmeWJFCdmYTzwIWrPrQxCw3k/TrLB/N8c=; b=XcuGVuOgVQW4cPMbFX3Kh+JDfXfNVzrNOIGYY7Ubhu37CxL6aNiDC5Pqhi9Hd2/xtD Gw8ZPJRfmD7Q0D9AwbSYy0Pv19B342RY+YxuhQzxOhLMJ4hRvbeFz1TbhsvOIXGCGLMn TocZ8+Q5cO5t03qWSpuLmDFcu7hgP81TiMiHWyKdrjl5XrX/nDuvCnP8xGoFD8BHip1P 6c+3arLvH64bgzYY1aP7lTjh2sDZN3Q12YhOnaZguiY9n4XAdqC7TDsvLNkUtnnC8vy4 E8E6JSyHx6RCE4BEV4EI7Gf8i2GfH5zxtuIad3wAN2yV5q3ZwTdC5I9+renXuJavrw5V pKxA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=LakZ+D3Q2eUmeWJFCdmYTzwIWrPrQxCw3k/TrLB/N8c=; b=eT2uf2PhQg614rNl9ZYwnxEK3oE+0RxrRvkiQuzfPYgolC4MUY4qmWxBJiVeaiF2cQ 3/9pPSqaoRFV9t+xeLEIKkYwSCDCcuhrERe0jBVYttbjLmbnLxPJx6rQ9bYX+K1N5PQq PJRXKBWzrUMB1+2hz5SRKGstMzDJAl7Cl7t8KjP+woTHka+X7PWrv4ETAqbNfiwIu4K7 vEWTO0rm9jfXhZ360uHo4qAmVA/JEKAKSWGDS+eNLsxFU53kjzN1Tr+ioQRrgGxjz6WG q3kUJysMMiekNCfrZCr3389f/s6mV+oTjZ6FNy2S1sAin6fLEhl7C87FS75SVmnWCDL+ HSCQ== X-Gm-Message-State: APjAAAUHVuF954Splv77n/G3MB+ZCQZgUiOLkdd3SVWCvLdkQmanbclP lS8VhCIAMfDHo6efVNMJzHJys6zXeYU= X-Google-Smtp-Source: APXvYqxj44v95W0H+IAkgQGsAQvW/dWb8x1ayNb/34HAZyb5AjTc7MgpDu3vRD2ujLJLFm6E1eg3AQ== X-Received: by 2002:adf:e404:: with SMTP id g4mr936963wrm.161.1557274402484; Tue, 07 May 2019 17:13:22 -0700 (PDT) Received: from vm.nix.is ([2a01:4f8:120:2468::2]) by smtp.gmail.com with ESMTPSA id n15sm5167825wrp.58.2019.05.07.17.13.21 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Tue, 07 May 2019 17:13:21 -0700 (PDT) From: =?UTF-8?q?=C3=86var=20Arnfj=C3=B6r=C3=B0=20Bjarmason?= To: git@vger.kernel.org Cc: Junio C Hamano , Denton Liu , Eric Sunshine , Johannes Schindelin , Johannes Sixt , =?UTF-8?q?SZEDER=20G=C3=A1bor?= , =?UTF-8?q?=C3=86var=20Arnfj=C3=B6r=C3=B0=20Bjarmason?= Subject: [RFC WIP PATCH v8 11/13] rebase: eliminate side-effects from can_fast_forward() Date: Wed, 8 May 2019 02:12:50 +0200 Message-Id: <20190508001252.15752-12-avarab@gmail.com> X-Mailer: git-send-email 2.21.0.1020.gf2820cf01a In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org The can_fast_forward() function is potentially much more expensive than is_interactive() since it e.g. might need to call is_linear_history(). So reversing the two looks like an obvious improvement, but doing so reveals a previously hidden caveat: We need the can_fast_forward() function to populate data used later, namely the "merge_bases" variable. This has been the case since it was added in 9a48a615b4 ("builtin rebase: try to fast forward when possible", 2018-09-04). So let's refactor it into two functions. Now we'll always call populate_merge_bases(), and then only call can_fast_forward() if is_interactive() is false, making this both faster in pathological cases, and more importantly easier to follow. Signed-off-by: Ævar Arnfjörð Bjarmason --- builtin/rebase.c | 41 +++++++++++++++++++++++++++-------------- 1 file changed, 27 insertions(+), 14 deletions(-) diff --git a/builtin/rebase.c b/builtin/rebase.c index ae6b9b42b8..cb5d7fcb53 100644 --- a/builtin/rebase.c +++ b/builtin/rebase.c @@ -878,24 +878,30 @@ static int is_linear_history(struct commit *from, struct commit *to) return 1; } -static int can_fast_forward(struct commit *onto, struct commit *upstream, +static void populate_merge_bases(struct commit *head, struct commit *onto, + struct commit_list *merge_bases, + struct object_id *merge_base) +{ + merge_bases = get_merge_bases(onto, head); + if (!merge_bases || merge_bases->next) { + oidcpy(merge_base, &null_oid); + return; + } + oidcpy(merge_base, &merge_bases->item->object.oid); +} + +static int can_fast_forward(struct commit *head, + struct commit *onto, struct commit *upstream, struct commit *restrict_revision, - struct object_id *head_oid, struct object_id *merge_base) + struct object_id *head_oid, + struct commit_list *merge_bases, + struct object_id *merge_base) { - struct commit *head = lookup_commit(the_repository, head_oid); - struct commit_list *merge_bases = NULL; int res = 0; if (!head) goto done; - merge_bases = get_merge_bases(onto, head); - if (!merge_bases || merge_bases->next) { - oidcpy(merge_base, &null_oid); - goto done; - } - - oidcpy(merge_base, &merge_bases->item->object.oid); if (!oideq(merge_base, &onto->object.oid)) goto done; @@ -1154,6 +1160,8 @@ int cmd_rebase(int argc, const char **argv, const char *prefix) OPT_END(), }; int i; + struct commit *head_commit; + struct commit_list *merge_bases = NULL; if (argc == 2 && !strcmp(argv[1], "-h")) usage_with_options(builtin_rebase_usage, @@ -1703,9 +1711,14 @@ int cmd_rebase(int argc, const char **argv, const char *prefix) * with new commits recreated by replaying their changes. This * optimization must not be done if this is an interactive rebase. */ - if (can_fast_forward(options.onto, options.upstream, options.restrict_revision, - &options.orig_head, &merge_base) && - !is_interactive(&options)) { + head_commit = lookup_commit(the_repository, &options.orig_head); + if (head_commit) + populate_merge_bases(head_commit, options.onto, merge_bases, + &merge_base); + if (!is_interactive(&options) && + can_fast_forward(head_commit, options.onto, options.upstream, + options.restrict_revision, &options.orig_head, + merge_bases, &merge_base)) { int flag; if (!(options.flags & REBASE_FORCE)) { -- 2.21.0.1020.gf2820cf01a