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: AS53758 23.128.96.0/24 X-Spam-Status: No, score=-3.8 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, 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 DFCDC1F852 for ; Sat, 15 Jan 2022 02:09:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232140AbiAOCJb (ORCPT ); Fri, 14 Jan 2022 21:09:31 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40402 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231258AbiAOCJ3 (ORCPT ); Fri, 14 Jan 2022 21:09:29 -0500 Received: from mail-wm1-x333.google.com (mail-wm1-x333.google.com [IPv6:2a00:1450:4864:20::333]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2737EC061574 for ; Fri, 14 Jan 2022 18:09:29 -0800 (PST) Received: by mail-wm1-x333.google.com with SMTP id c66so9326570wma.5 for ; Fri, 14 Jan 2022 18:09:29 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=message-id:from:date:subject:fcc:content-transfer-encoding :mime-version:to:cc; bh=nOeDW/c0kpL9sr4Yco14uIy7ujLkaqdJi5gTL4kPYvk=; b=TDGKCrCcI07lmnyM8nD8deZAE2A7uB9CMlblC1ufHG/ur06oP3k1KVps9ew+SH+y6k QJ4Mf+rH1Biq8FyM2qBA7vIb5aQwmnci5kNZl4w9N/RBJStajQsUBjx6g3VUzXqVPG23 lnOd6FIaBp7PaDP/cdvFdleE1wHJWzJziyx9xu2Tte97LFj1w/xNtzpsetvxm1ItxTsF wgVZ5ky48pv94BRWbHQIKnvJT2quaisB81N8pL2Vm8nIc2lrnno23d/s4JLSP7jVbQA6 Ed19fGhKQLWKDcwM9qNOcLZrip+JqtZkgc450QgWuq7EsVDiyUM5oH137eStYvG3Zloy 4mxg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:from:date:subject:fcc :content-transfer-encoding:mime-version:to:cc; bh=nOeDW/c0kpL9sr4Yco14uIy7ujLkaqdJi5gTL4kPYvk=; b=JlvCatj8UlvKI3Ac+GAUqgxTlsq9gNj8F6kNASjFHZsMsOkLdfwdM66s0yGZDWjYSa eCOrfeRgBJxSySrYwekEtbjFJfVN4ex4/Nak5elws0TtLCsBBNod6zg1PgzmC9hEkVTm 0bbtHJGCDPVgKLXYNA0XF0lPe4Ag6odEd9DpgXV3zaLz7ah36d4LWOTtpdWlRy0MKQoC DIR4xdnNIXa+jiUiV+HdsuI7TBtPGMZaMw1gfqDDZqvpCOZikNWlh972OBqww3KDziux n0PyXNs7IGIbFzMFlheTXAP7sBVnydFBusVOE5vcug6mUzEh/J8E3z4nVKHiomIeIyI5 VfUQ== X-Gm-Message-State: AOAM530EmwbwaGbEKw1br+Hkh71/OqZ10zWXJT+8/ODjFVVskTbFwO7N DWCBLiBYkFYLZkvRuv9Tof1ZDB3yKQI= X-Google-Smtp-Source: ABdhPJws5EkYyQmHXdRdBfiPY7J/nHNO2+508oNsqGcjfp+CpbcBLcpOqfyWeh4cDsPgIVoNVg3x0g== X-Received: by 2002:a5d:4584:: with SMTP id p4mr10417557wrq.607.1642212567405; Fri, 14 Jan 2022 18:09:27 -0800 (PST) Received: from [127.0.0.1] ([13.74.141.28]) by smtp.gmail.com with ESMTPSA id r132sm7270985wma.34.2022.01.14.18.09.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 14 Jan 2022 18:09:26 -0800 (PST) Message-Id: From: "Elijah Newren via GitGitGadget" Date: Sat, 15 Jan 2022 02:09:26 +0000 Subject: [PATCH] merge-ort: avoid assuming all renames detected Fcc: Sent Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit MIME-Version: 1.0 To: git@vger.kernel.org Cc: Taylor Blau , Elijah Newren , Elijah Newren Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org From: Elijah Newren In commit 8b09a900a1 ("merge-ort: restart merge with cached renames to reduce process entry cost", 2021-07-16), we noted that in the merge-ort steps of collect_merge_info() detect_and_process_renames() process_entries() that process_entries() was expensive, and we could often make it cheaper by changing this to collect_merge_info() detect_and_process_renames() collect_merge_info() detect_and_process_renames() process_entries() because the second collect_merge_info() would be cheaper (we could avoid traversing into some directories), the second detect_and_process_renames() would be free since we had already detected all renames, and then process_entries() has far fewer entries to handle. However, this was built on the assumption that the first detect_and_process_renames() actually detected all potential renames. If someone has merge.renameLimit set to some small value, that assumption is violated which manifests later with the following message: $ git -c merge.renameLimit=1 rebase upstream ... git: merge-ort.c:546: clear_or_reinit_internal_opts: Assertion `renames->cached_pairs_valid_side == 0' failed. Turn off this cache-renames-and-restart whenever we cannot detect all renames, and add a testcase that would have caught this problem. Reported-by: Taylor Blau Signed-off-by: Elijah Newren --- merge-ort: avoid assuming all renames detected Fixes https://lore.kernel.org/git/YeHTIfEutLYM4TIU@nand.local/ Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1194%2Fnewren%2Favoid-assertion-assuming-renames-found-v1 Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1194/newren/avoid-assertion-assuming-renames-found-v1 Pull-Request: https://github.com/git/git/pull/1194 merge-ort.c | 4 ++ t/t6429-merge-sequence-rename-caching.sh | 67 ++++++++++++++++++++++++ 2 files changed, 71 insertions(+) diff --git a/merge-ort.c b/merge-ort.c index c3197970219..143d274f117 100644 --- a/merge-ort.c +++ b/merge-ort.c @@ -3060,6 +3060,10 @@ static int detect_and_process_renames(struct merge_options *opt, trace2_region_enter("merge", "regular renames", opt->repo); detection_run |= detect_regular_renames(opt, MERGE_SIDE1); detection_run |= detect_regular_renames(opt, MERGE_SIDE2); + if (renames->needed_limit != 0) { + renames->cached_pairs_valid_side = 0; + renames->redo_after_renames = 0; + } if (renames->redo_after_renames && detection_run) { int i, side; struct diff_filepair *p; diff --git a/t/t6429-merge-sequence-rename-caching.sh b/t/t6429-merge-sequence-rename-caching.sh index 035edc40b1e..f2bc8a7d2a2 100755 --- a/t/t6429-merge-sequence-rename-caching.sh +++ b/t/t6429-merge-sequence-rename-caching.sh @@ -697,4 +697,71 @@ test_expect_success 'caching renames only on upstream side, part 2' ' ) ' +# +# The following testcase just creates two simple renames (slightly modified +# on both sides but without conflicting changes), and a directory full of +# files that are otherwise uninteresting. The setup is as follows: +# +# base: unrelated/ +# numbers +# values +# upstream: modify: numbers +# modify: values +# topic: add: unrelated/foo +# modify: numbers +# modify: values +# rename: numbers -> sequence +# rename: values -> progression +# +# This is a trivial rename case, but we're curious what happens with a very +# low renameLimit interacting with the restart optimization trying to notice +# that unrelated/ looks like a trivial merge candidate. +# +test_expect_success 'avoid assuming we detected renames' ' + git init redo-weirdness && + ( + cd redo-weirdness && + + mkdir unrelated && + for i in $(test_seq 1 10) + do + >unrelated/$i + done && + test_seq 2 10 >numbers && + test_seq 12 20 >values && + git add numbers values unrelated/ && + git commit -m orig && + + git branch upstream && + git branch topic && + + git switch upstream && + test_seq 1 10 >numbers && + test_seq 11 20 >values && + git add numbers && + git commit -m "Some tweaks" && + + git switch topic && + + >unrelated/foo && + test_seq 2 12 >numbers && + test_seq 12 22 >values && + git add numbers values unrelated/ && + git mv numbers sequence && + git mv values progression && + git commit -m A && + + # + # Actual testing + # + + git switch --detach topic^0 && + + test_must_fail git -c merge.renameLimit=1 rebase upstream && + + git ls-files -u >actual && + ! test_file_is_empty actual + ) +' + test_done base-commit: 1ffcbaa1a5f10c9f706314d77f88de20a4a498c2 -- gitgitgadget