From patchwork Wed Oct 21 13:22:34 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Elijah Newren X-Patchwork-Id: 11849091 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B756CC55178 for ; Wed, 21 Oct 2020 13:22:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 54A80221FC for ; Wed, 21 Oct 2020 13:22:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="uyXqNXCH" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2438054AbgJUNWq (ORCPT ); Wed, 21 Oct 2020 09:22:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54788 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2437452AbgJUNWo (ORCPT ); Wed, 21 Oct 2020 09:22:44 -0400 Received: from mail-wr1-x442.google.com (mail-wr1-x442.google.com [IPv6:2a00:1450:4864:20::442]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5892EC0613CE for ; Wed, 21 Oct 2020 06:22:43 -0700 (PDT) Received: by mail-wr1-x442.google.com with SMTP id i1so3166760wro.1 for ; Wed, 21 Oct 2020 06:22:43 -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:fcc :content-transfer-encoding:mime-version:to:cc; bh=mVdReK6IljK6KItoeZdc9pBvxXF5d9jZUJhEdnNCf44=; b=uyXqNXCHc3VdmkVH3Ca68UbhU1z4XPNYJh4SmlU+TIZmO/WmhxsRkUbRfLr+glUXOJ ZbhrOKTruXhRsS72/fQ9GkTC6Ky2Mgyyx0OeONmFbTTUhvKP05qe95E66PH2hJp0PnlS KTtJFIN3oNdcbrRRphCzsptMXZysQPK33WrWCKCs63DSHf/GOmi54rtnokcfyjIjRAYn RhBW+ZcGBiEo0q4U3na6pXZUQ/8HXBIwFdObgFkzr/8lR/PiY2O+fDVK3m6iyjSUjPCz CZo1xFECsVnY34zdKAUIb0fEhs8/EKhcru01IkdHQUNHLdwW3EFpe2445dxFnTahQnlg PnoA== 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:fcc:content-transfer-encoding:mime-version:to:cc; bh=mVdReK6IljK6KItoeZdc9pBvxXF5d9jZUJhEdnNCf44=; b=B2PLrFwNjQdld++jITuGIaCelX+Kas8sO/RKoxsPmbCjAnR7kIXYgTM61V0nT5PxO2 jMYWerhIEYy28n5/qeM8bGxlW09tBPYOq2AN66YWZqw89nkfU337nK2p7ZWDLkH6MxHC er+E+v+cAJ+3yZVWv2UQYvuTsPz8uIY5FK+6FeuFCb2viUEss0AaKGtyVurPp9nuXSs/ AAscnVRMULVWG5qW/sXNIOG6IR8DZ39IIDzRUxZLefbj6UcndbaBTw3RRAdeTdB6Mwie bkE4hUfQjJFpPVrKrwX7ujI4TSjFcPh6RK0aTZXWe5q03lIjTv6Fwsiif7e2HzafHkKA KGHQ== X-Gm-Message-State: AOAM531k4cPT3twAquu/AtoBKLJcmBjrgfZvhOo9d/Jz0a5MJOjsWhjN V+QTbMBMmOH/0/o3vFhQqLBVPzxkPHk= X-Google-Smtp-Source: ABdhPJxRxGkQqpg2QT6W4Q49jA3OOHbHTTJjOnM9OOTA/K4SmKLHUpfJDsCHVfhQVgJwqoLi+SNxiQ== X-Received: by 2002:adf:e80f:: with SMTP id o15mr4891196wrm.308.1603286561634; Wed, 21 Oct 2020 06:22:41 -0700 (PDT) Received: from [127.0.0.1] ([13.74.141.28]) by smtp.gmail.com with ESMTPSA id o140sm3145663wme.43.2020.10.21.06.22.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 21 Oct 2020 06:22:41 -0700 (PDT) Message-Id: In-Reply-To: References: Date: Wed, 21 Oct 2020 13:22:34 +0000 Subject: [PATCH 3/4] fast-rebase: demonstrate merge-ort's API via temporary/hidden command Fcc: Sent MIME-Version: 1.0 To: git@vger.kernel.org Cc: Elijah Newren , Elijah Newren Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org From: Elijah Newren From: Elijah Newren Add a special built-in that is only of use to git-developers and only during the development of merge-ort, and which is designed to immediately fail and print: git: 'fast-rebase' is not a git command unless a special GIT_TEST_MERGE_ALGORITHM environment variable is set. This special builtin serves two purposes: 1) Demonstrate the desired API of merge-ort. In particular, fast-rebase takes advantage of the separation of the merging operation from the updating of the index and working tree, to allow it to pick N commits, but only update the index and working tree once at the end. Look for the calls to merge_inmemory_nonrecursive() and merge_switch_to_result(). 2) Provide a convenient benchmark that isn't polluted by the heavy disk writing and forking of unnecessary processes that comes from sequencer.c and merge-recursive.c. fast-rebase is not meant to replace sequencer.c, just give ideas on how sequencer.c can be changed. Updating sequencer.c with these goals is probably a large amount of work; writing a simple targeted command with no documentation, less-than-useful help messages, numerous limitations in terms of flags it can accept and situations it can handle, and which is flagged off from users is a much easier interim step. Signed-off-by: Elijah Newren --- Makefile | 1 + builtin.h | 1 + builtin/fast-rebase.c | 210 ++++++++++++++++++++++++++++++++++++++++++ git.c | 1 + 4 files changed, 213 insertions(+) create mode 100644 builtin/fast-rebase.c diff --git a/Makefile b/Makefile index 382fe73c76..1b40d780fa 100644 --- a/Makefile +++ b/Makefile @@ -1087,6 +1087,7 @@ BUILTIN_OBJS += builtin/difftool.o BUILTIN_OBJS += builtin/env--helper.o BUILTIN_OBJS += builtin/fast-export.o BUILTIN_OBJS += builtin/fast-import.o +BUILTIN_OBJS += builtin/fast-rebase.o BUILTIN_OBJS += builtin/fetch-pack.o BUILTIN_OBJS += builtin/fetch.o BUILTIN_OBJS += builtin/fmt-merge-msg.o diff --git a/builtin.h b/builtin.h index 53fb290963..75ff7dc8a9 100644 --- a/builtin.h +++ b/builtin.h @@ -151,6 +151,7 @@ int cmd_difftool(int argc, const char **argv, const char *prefix); int cmd_env__helper(int argc, const char **argv, const char *prefix); int cmd_fast_export(int argc, const char **argv, const char *prefix); int cmd_fast_import(int argc, const char **argv, const char *prefix); +int cmd_fast_rebase(int argc, const char **argv, const char *prefix); int cmd_fetch(int argc, const char **argv, const char *prefix); int cmd_fetch_pack(int argc, const char **argv, const char *prefix); int cmd_fmt_merge_msg(int argc, const char **argv, const char *prefix); diff --git a/builtin/fast-rebase.c b/builtin/fast-rebase.c new file mode 100644 index 0000000000..ae78a8b1c1 --- /dev/null +++ b/builtin/fast-rebase.c @@ -0,0 +1,210 @@ +/* + * "git fast-rebase" builtin command + * + * FAST: Forking Any Subprocesses (is) Taboo + * + * This is meant SOLELY as a demo of what is possible. sequencer.c and + * rebase.c should be refactored to use the ideas here, rather than attempting + * to extend this file to replace those (unless Phillip or Dscho say that + * refactoring is too hard and we need a clean slate, but I'm guessing that + * refactoring is the better route). + */ + +#define USE_THE_INDEX_COMPATIBILITY_MACROS +#include "builtin.h" + +#include "cache-tree.h" +#include "commit.h" +#include "lockfile.h" +#include "merge-ort.h" +#include "refs.h" +#include "revision.h" +#include "sequencer.h" +#include "strvec.h" +#include "tree.h" + +static const char *short_commit_name(struct commit *commit) +{ + return find_unique_abbrev(&commit->object.oid, DEFAULT_ABBREV); +} + +static struct commit *peel_committish(const char *name) +{ + struct object *obj; + struct object_id oid; + + if (get_oid(name, &oid)) + return NULL; + obj = parse_object(the_repository, &oid); + return (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT); +} + +static char *get_author(const char *message) +{ + size_t len; + const char *a; + + a = find_commit_header(message, "author", &len); + if (a) + return xmemdupz(a, len); + + return NULL; +} + +static struct commit *create_commit(struct tree *tree, + struct commit *based_on, + struct commit *parent) +{ + struct object_id ret; + struct object *obj; + struct commit_list *parents = NULL; + char *author; + char *sign_commit = NULL; + struct commit_extra_header *extra; + struct strbuf msg = STRBUF_INIT; + const char *out_enc = get_commit_output_encoding(); + const char *message = logmsg_reencode(based_on, NULL, out_enc); + const char *orig_message = NULL; + const char *exclude_gpgsig[] = { "gpgsig", NULL }; + + commit_list_insert(parent, &parents); + extra = read_commit_extra_headers(based_on, exclude_gpgsig); + find_commit_subject(message, &orig_message); + strbuf_addstr(&msg, orig_message); + author = get_author(message); + reset_ident_date(); + if (commit_tree_extended(msg.buf, msg.len, &tree->object.oid, parents, + &ret, author, NULL, sign_commit, extra)) { + error(_("failed to write commit object")); + return NULL; + } + free(author); + strbuf_release(&msg); + + obj = parse_object(the_repository, &ret); + return (struct commit *)obj; +} + +int cmd_fast_rebase(int argc, const char **argv, const char *prefix) +{ + struct commit *onto; + struct commit *last_commit = NULL, *last_picked_commit = NULL; + struct object_id head; + struct lock_file lock = LOCK_INIT; + int clean = 1; + struct strvec rev_walk_args = STRVEC_INIT; + struct rev_info revs; + struct commit *commit; + struct merge_options merge_opt; + struct tree *next_tree, *base_tree, *head_tree; + struct merge_result result; + struct strbuf reflog_msg = STRBUF_INIT; + struct strbuf branch_name = STRBUF_INIT; + + if (argc == 2 && !strcmp(argv[1], "-h")) { + printf("Sorry, I am not a psychiatrist; I can not give you the help you need. Oh, you meant usage...\n"); + exit(129); + } + + if (!getenv("GIT_TEST_MERGE_ALGORITHM")) { + fprintf_ln(stderr, _("git: 'fast-rebase' is not a git command. See 'git --help'.")); + exit(1); + } + + if (argc != 5 || strcmp(argv[1], "--onto")) + die("usage: read the code, figure out how to use it, then do so"); + + onto = peel_committish(argv[2]); + strbuf_addf(&branch_name, "refs/heads/%s", argv[4]); + + /* Sanity check */ + if (get_oid("HEAD", &head)) + die(_("Cannot read HEAD")); + assert(oideq(&onto->object.oid, &head)); + + hold_locked_index(&lock, LOCK_DIE_ON_ERROR); + assert(repo_read_index(the_repository) >= 0); + + repo_init_revisions(the_repository, &revs, NULL); + revs.verbose_header = 1; + revs.max_parents = 1; + revs.cherry_mark = 1; + revs.limited = 1; + revs.reverse = 1; + revs.right_only = 1; + revs.sort_order = REV_SORT_IN_GRAPH_ORDER; + revs.topo_order = 1; + strvec_pushl(&rev_walk_args, "", argv[4], "--not", argv[3], NULL); + + if (setup_revisions(rev_walk_args.nr, rev_walk_args.v, &revs, NULL) > 1) + return error(_("unhandled options")); + + strvec_clear(&rev_walk_args); + + if (prepare_revision_walk(&revs) < 0) + return error(_("error preparing revisions")); + + init_merge_options(&merge_opt, the_repository); + memset(&result, 0, sizeof(result)); + merge_opt.show_rename_progress = 1; + merge_opt.branch1 = "HEAD"; + head_tree = get_commit_tree(onto); + result.tree = head_tree; + last_commit = onto; + while ((commit = get_revision(&revs))) { + struct commit *base; + + fprintf(stderr, "Rebasing %s...\r", + oid_to_hex(&commit->object.oid)); + assert(commit->parents && !commit->parents->next); + base = commit->parents->item; + + next_tree = get_commit_tree(commit); + base_tree = get_commit_tree(base); + + merge_opt.branch2 = short_commit_name(commit); + merge_opt.ancestor = xstrfmt("parent of %s", merge_opt.branch2); + + merge_inmemory_nonrecursive(&merge_opt, + base_tree, + result.tree, + next_tree, + &result); + + free((char*)merge_opt.ancestor); + merge_opt.ancestor = NULL; + if (!result.clean) + die("Aborting: Hit a conflict and restarting is not implemented."); + last_picked_commit = commit; + last_commit = create_commit(result.tree, commit, last_commit); + } + fprintf(stderr, "\nDone.\n"); + /* TODO: There should be some kind of rev_info_free(&revs) call... */ + memset(&revs, 0, sizeof(revs)); + + merge_switch_to_result(&merge_opt, head_tree, &result, 1, !result.clean); + + if (result.clean < 0) + exit(128); + + strbuf_addf(&reflog_msg, "finish rebase %s onto %s", + oid_to_hex(&last_picked_commit->object.oid), + oid_to_hex(&last_commit->object.oid)); + if (update_ref(reflog_msg.buf, branch_name.buf, + &last_commit->object.oid, + &last_picked_commit->object.oid, + REF_NO_DEREF, UPDATE_REFS_MSG_ON_ERR)) { + error(_("could not update %s"), argv[4]); + die("Failed to update %s", argv[4]); + } + if (create_symref("HEAD", branch_name.buf, reflog_msg.buf) < 0) + die(_("unable to update HEAD")); + strbuf_release(&reflog_msg); + strbuf_release(&branch_name); + + prime_cache_tree(the_repository, the_repository->index, result.tree); + if (write_locked_index(&the_index, &lock, + COMMIT_LOCK | SKIP_IF_UNCHANGED)) + die(_("unable to write %s"), get_index_file()); + return (clean == 0); +} diff --git a/git.c b/git.c index 4bdcdad2cc..af84f11e69 100644 --- a/git.c +++ b/git.c @@ -512,6 +512,7 @@ static struct cmd_struct commands[] = { { "env--helper", cmd_env__helper }, { "fast-export", cmd_fast_export, RUN_SETUP }, { "fast-import", cmd_fast_import, RUN_SETUP | NO_PARSEOPT }, + { "fast-rebase", cmd_fast_rebase, RUN_SETUP /* | NEED_WORK_TREE */ }, { "fetch", cmd_fetch, RUN_SETUP }, { "fetch-pack", cmd_fetch_pack, RUN_SETUP | NO_PARSEOPT }, { "fmt-merge-msg", cmd_fmt_merge_msg, RUN_SETUP },