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=-3.7 required=3.0 tests=AWL,BAYES_00, DKIM_ADSP_CUSTOM_MED,DKIM_INVALID,DKIM_SIGNED, 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 1DFE11F4C0 for ; Thu, 24 Oct 2019 12:18:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2439658AbfJXMSO (ORCPT ); Thu, 24 Oct 2019 08:18:14 -0400 Received: from mail-wr1-f65.google.com ([209.85.221.65]:46190 "EHLO mail-wr1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2439651AbfJXMSO (ORCPT ); Thu, 24 Oct 2019 08:18:14 -0400 Received: by mail-wr1-f65.google.com with SMTP id n15so15032606wrw.13 for ; Thu, 24 Oct 2019 05:18:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=message-id:in-reply-to:references:from:date:subject:mime-version :content-transfer-encoding:fcc:to:cc; bh=ZP2UTVenr02w5LyaAfckUPuBy59/AM0X84J+Ynpgr2Q=; b=M72E6IHtlTlSiFzXhfT/eCm5Rb/Y4oJvME7DhiFrgIbQhSCHQAFCLUjq+oKupvvaIr U2PAmhgrKkrWz1Q7QlF7IED18YwvC4Fnu0CxiQcTCaTi+5UV4bXNvfOxAl1K/p5WBE+y cyrQDoZcccj7mcGd1SSaPXE3fl9EQZ378wug+ZQEGGLw0lHP5Y1ExEfRwe4/Y93v/6vf v+/MfHhIlJ5sV3L4UKjGiGxtMtRwFLoy2pH8CoHrjvU3VqEqSCxve3X/qmfb/C/GrF7J +vaiL6CYS5r5aFr0ub5b+ntQNyVvpo09wHMOegnXGL44D8+8LWw2k7csubO42mQQt5Px RqCg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:message-id:in-reply-to:references:from:date :subject:mime-version:content-transfer-encoding:fcc:to:cc; bh=ZP2UTVenr02w5LyaAfckUPuBy59/AM0X84J+Ynpgr2Q=; b=QabESFQF2NE9S3cXpMAXcK+qA3zTgkd0zohklPCE2d8WtnlGms13BeP1BLHYU2gx/e AZiZJoKmBPVGK8prF11CI2LbqsSyUJO4Ys0Jdzir2OWgoAfHTSa+/1oHKdq/fggwy2fg vWA1ik2foros7Nd59RmNAK3elrOLtn7EI+3QTq7Hp8N+r48OAmhAkjhsP2xvnR+Ysev8 Qhd0EpfIq7MiOKgdGnON6WAvV/rSXzMhDBurLzKV7VORCektJTdO0kAih34c/WND0YQl bgSmBEuTh8gXXVbzRpEnVMGVINn1TN889aHt3aijrLglag6zwhcxqJVcBHEXFgYeZSxa lTug== X-Gm-Message-State: APjAAAWAC+Y7xxoQsmbsvOZl7mWcQifv/7e8KXbpIyez0QLWEDmMQYHV PyIJi0i+38r2bFIZUCOdDlrZaFxd X-Google-Smtp-Source: APXvYqw2KCjL69yoWCsT7tqoSYs88XKQ0xaaAGuCa6UZtQSovtfVMkYUXr/qFA0FcGDrvniQLw65FA== X-Received: by 2002:adf:a48c:: with SMTP id g12mr3407405wrb.212.1571919491402; Thu, 24 Oct 2019 05:18:11 -0700 (PDT) Received: from [127.0.0.1] ([13.74.141.28]) by smtp.gmail.com with ESMTPSA id e9sm8885823wrr.13.2019.10.24.05.18.10 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 24 Oct 2019 05:18:10 -0700 (PDT) Message-Id: In-Reply-To: References: From: "Derrick Stolee via GitGitGadget" Date: Thu, 24 Oct 2019 12:18:08 +0000 Subject: [PATCH v3 2/2] commit-graph: fix writing first commit-graph during fetch MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Fcc: Sent To: git@vger.kernel.org Cc: johannes.schindelin@gmx.de, peff@peff.net, szeder.dev@gmail.com, Derrick Stolee , Junio C Hamano , Derrick Stolee Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org From: Derrick Stolee The previous commit includes a failing test for an issue around fetch.writeCommitGraph and fetching in a repo with a submodule. Here, we fix that bug and set the test to "test_expect_success". The problem arises with this set of commands when the remote repo at has a submodule. Note that --recurse-submodules is not needed to demonstrate the bug. $ git clone test $ cd test $ git -c fetch.writeCommitGraph=true fetch origin Computing commit graph generation numbers: 100% (12/12), done. BUG: commit-graph.c:886: missing parent for commit Aborted (core dumped) As an initial fix, I converted the code in builtin/fetch.c that calls write_commit_graph_reachable() to instead launch a "git commit-graph write --reachable --split" process. That code worked, but is not how we want the feature to work long-term. That test did demonstrate that the issue must be something to do with internal state of the 'git fetch' process. The write_commit_graph() method in commit-graph.c ensures the commits we plan to write are "closed under reachability" using close_reachable(). This method walks from the input commits, and uses the UNINTERESTING flag to mark which commits have already been visited. This allows the walk to take O(N) time, where N is the number of commits, instead of O(P) time, where P is the number of paths. (The number of paths can be exponential in the number of commits.) However, the UNINTERESTING flag is used in lots of places in the codebase. This flag usually means some barrier to stop a commit walk, such as in revision-walking to compare histories. It is not often cleared after the walk completes because the starting points of those walks do not have the UNINTERESTING flag, and clear_commit_marks() would stop immediately. This is happening during a 'git fetch' call with a remote. The fetch negotiation is comparing the remote refs with the local refs and marking some commits as UNINTERESTING. I tested running clear_commit_marks_many() to clear the UNINTERESTING flag inside close_reachable(), but the tips did not have the flag, so that did nothing. It turns out that the calculate_changed_submodule_paths() method is at fault. Thanks, Peff, for pointing out this detail! More specifically, for each submodule, the collect_changed_submodules() runs a revision walk to essentially do file-history on the list of submodules. That revision walk marks commits UNININTERESTING if they are simplified away by not changing the submodule. Instead, I finally arrived on the conclusion that I should use a flag that is not used in any other part of the code. In commit-reach.c, a number of flags were defined for commit walk algorithms. The REACHABLE flag seemed like it made the most sense, and it seems it was not actually used in the file. The REACHABLE flag was used in early versions of commit-reach.c, but was removed by 4fbcca4 (commit-reach: make can_all_from_reach... linear, 2018-07-20). Add the REACHABLE flag to commit-graph.c and use it instead of UNINTERESTING in close_reachable(). This fixes the bug in manual testing. Reported-by: Johannes Schindelin Helped-by: Jeff King Helped-by: Szeder Gábor Signed-off-by: Derrick Stolee --- commit-graph.c | 11 +++++++---- commit-reach.c | 1 - object.h | 3 ++- t/t5510-fetch.sh | 2 +- 4 files changed, 10 insertions(+), 7 deletions(-) diff --git a/commit-graph.c b/commit-graph.c index fc4a43b8d6..0aea7b2ae5 100644 --- a/commit-graph.c +++ b/commit-graph.c @@ -41,6 +41,9 @@ #define GRAPH_MIN_SIZE (GRAPH_HEADER_SIZE + 4 * GRAPH_CHUNKLOOKUP_WIDTH \ + GRAPH_FANOUT_SIZE + the_hash_algo->rawsz) +/* Remember to update object flag allocation in object.h */ +#define REACHABLE (1u<<15) + char *get_commit_graph_filename(const char *obj_dir) { char *filename = xstrfmt("%s/info/commit-graph", obj_dir); @@ -1030,11 +1033,11 @@ static void add_missing_parents(struct write_commit_graph_context *ctx, struct c { struct commit_list *parent; for (parent = commit->parents; parent; parent = parent->next) { - if (!(parent->item->object.flags & UNINTERESTING)) { + if (!(parent->item->object.flags & REACHABLE)) { ALLOC_GROW(ctx->oids.list, ctx->oids.nr + 1, ctx->oids.alloc); oidcpy(&ctx->oids.list[ctx->oids.nr], &(parent->item->object.oid)); ctx->oids.nr++; - parent->item->object.flags |= UNINTERESTING; + parent->item->object.flags |= REACHABLE; } } } @@ -1052,7 +1055,7 @@ static void close_reachable(struct write_commit_graph_context *ctx) display_progress(ctx->progress, i + 1); commit = lookup_commit(ctx->r, &ctx->oids.list[i]); if (commit) - commit->object.flags |= UNINTERESTING; + commit->object.flags |= REACHABLE; } stop_progress(&ctx->progress); @@ -1089,7 +1092,7 @@ static void close_reachable(struct write_commit_graph_context *ctx) commit = lookup_commit(ctx->r, &ctx->oids.list[i]); if (commit) - commit->object.flags &= ~UNINTERESTING; + commit->object.flags &= ~REACHABLE; } stop_progress(&ctx->progress); } diff --git a/commit-reach.c b/commit-reach.c index 3ea174788a..4ca7e706a1 100644 --- a/commit-reach.c +++ b/commit-reach.c @@ -10,7 +10,6 @@ #include "commit-reach.h" /* Remember to update object flag allocation in object.h */ -#define REACHABLE (1u<<15) #define PARENT1 (1u<<16) #define PARENT2 (1u<<17) #define STALE (1u<<18) diff --git a/object.h b/object.h index 0120892bbd..25f5ab3d54 100644 --- a/object.h +++ b/object.h @@ -68,7 +68,8 @@ struct object_array { * bisect.c: 16 * bundle.c: 16 * http-push.c: 16-----19 - * commit-reach.c: 15-------19 + * commit-graph.c: 15 + * commit-reach.c: 16-----19 * sha1-name.c: 20 * list-objects-filter.c: 21 * builtin/fsck.c: 0--3 diff --git a/t/t5510-fetch.sh b/t/t5510-fetch.sh index cc76e1ce50..e16b7b8db2 100755 --- a/t/t5510-fetch.sh +++ b/t/t5510-fetch.sh @@ -583,7 +583,7 @@ test_expect_success 'fetch.writeCommitGraph' ' ) ' -test_expect_failure 'fetch.writeCommitGraph with submodules' ' +test_expect_success 'fetch.writeCommitGraph with submodules' ' git clone dups super && ( cd super && -- gitgitgadget