From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Tan Subject: [PATCH v2 15/19] pull: teach git pull about --rebase Date: Wed, 3 Jun 2015 14:48:59 +0800 Message-ID: <1433314143-4478-16-git-send-email-pyokagan@gmail.com> References: <1433314143-4478-1-git-send-email-pyokagan@gmail.com> Cc: Stefan Beller , Johannes Schindelin , Stephen Robin , Paul Tan To: git@vger.kernel.org X-From: git-owner@vger.kernel.org Wed Jun 03 08:51:01 2015 Return-path: Envelope-to: gcvg-git-2@plane.gmane.org Received: from vger.kernel.org ([209.132.180.67]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Z02Vp-00052N-4X for gcvg-git-2@plane.gmane.org; Wed, 03 Jun 2015 08:50:53 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753396AbbFCGul (ORCPT ); Wed, 3 Jun 2015 02:50:41 -0400 Received: from mail-pd0-f174.google.com ([209.85.192.174]:35448 "EHLO mail-pd0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753339AbbFCGua (ORCPT ); Wed, 3 Jun 2015 02:50:30 -0400 Received: by pdbnf5 with SMTP id nf5so748148pdb.2 for ; Tue, 02 Jun 2015 23:50:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=5o4pmY/O5u2vkFmJbcKYD2Wk2CZHnlH4Vsb9S6RySWY=; b=Lu7cdLX3tpAHk+HAHhBVuuPDDhk0r/gkazlJuNXgIb4sm8BCLJyr33GbhilAtcvbZJ dz3Zc2lFTSEhxwiAG5vqzJUJHBps1dmZQ+vBk/IcUlhfRTWjkHdmHXSGPODb7cZmsIVp QACEQG1ZrJEbdBVHPAWL86dYFnRG1GZwEJESFFwWdhc7L2bLLW408aLSw6ffW5vmwqxZ YkdTB/QnN7Ad303tRW2jTYD3+XDfQxzakhHV7msVJqtlcoi8pULCTtb7RKiFFzxOD8Pn 5gXhBQ9x2DzQp/KrRmQjHlx43+l4Wyb/5azAlFo5HNA7f3syMi5W3H8Vqer0AsdMxEYN HyUw== X-Received: by 10.70.138.70 with SMTP id qo6mr56200032pdb.163.1433314229765; Tue, 02 Jun 2015 23:50:29 -0700 (PDT) Received: from yoshi.pyokagan.tan ([116.86.132.138]) by mx.google.com with ESMTPSA id qt4sm19474130pbc.86.2015.06.02.23.50.26 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 02 Jun 2015 23:50:28 -0700 (PDT) X-Mailer: git-send-email 2.1.4 In-Reply-To: <1433314143-4478-1-git-send-email-pyokagan@gmail.com> Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: Since cd67e4d (Teach 'git pull' about --rebase, 2007-11-28), if the --rebase option is set, git-rebase is run instead of git-merge. Re-implement this by introducing run_rebase(), which is called instead of run_merge() if opt_rebase is a true value. Since c85c792 (pull --rebase: be cleverer with rebased upstream branches, 2008-01-26), git-pull handles the case where the upstream branch was rebased since it was last fetched. The fork point (old remote ref) of the branch from the upstream branch is calculated before fetch, and then rebased from onto the new remote head (merge_head) after fetch. Re-implement this by introducing get_merge_branch_2() and get_merge_branch_1() to find the upstream branch for the specified/current branch, and get_rebase_fork_point() which will find the fork point between the upstream branch and current branch. However, the above change created a problem where git-rebase cannot detect commits that are already upstream, and thus may result in unnecessary conflicts. cf65426 (pull --rebase: Avoid spurious conflicts and reapplying unnecessary patches, 2010-08-12) fixes this by ignoring the above old remote ref if it is contained within the merge base of the merge head and the current branch. This is re-implemented in run_rebase() where fork_point is not used if it is the merge base returned by get_octopus_merge_base(). Helped-by: Stefan Beller Helped-by: Johannes Schindelin Signed-off-by: Paul Tan --- Notes: v2 * enum rebase_type gained a new value REBASE_INVALID = -1 to represent invalid values passed to --rebase. We can't immediately die() on invalid values because we need parse_options() to show the git-pull usage as well. * parse_config_rebase() now returns an enum rebase_type to make it clear what kind of value it returns. * parse_config_rebase() now does not depend on git_config_maybe_bool() returning 1 for true and 0 for false. If it returns 0, it is REBASE_FALSE. If it returns any true value >=0, it is interpreted as REBASE_TRUE. * get_merge_branch_1() has been renamed to get_upstream_branch() to be consistent with the similar get_upstream_branch() in sha1_name.c. * get_merge_branch_2() has been renamed to get_tracking_branch() to indicate what it is doing: deriving the remote tracking branch from the refspec. * Various small variable re-names and docstring tweaks. Hopefully everything reads better now. builtin/pull.c | 239 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 237 insertions(+), 2 deletions(-) diff --git a/builtin/pull.c b/builtin/pull.c index c44cc90..7645937 100644 --- a/builtin/pull.c +++ b/builtin/pull.c @@ -15,6 +15,45 @@ #include "dir.h" #include "refs.h" +enum rebase_type { + REBASE_INVALID = -1, + REBASE_FALSE = 0, + REBASE_TRUE, + REBASE_PRESERVE +}; + +/** + * Parses the value of --rebase, branch.*.rebase or pull.rebase. If value is a + * false value, returns REBASE_FALSE. If value is a true value, returns + * REBASE_TRUE. If value is "preserve", returns REBASE_PRESERVE. Otherwise, + * returns -1 to signify an invalid value. + */ +static enum rebase_type parse_config_rebase(const char *value) +{ + int v = git_config_maybe_bool("pull.rebase", value); + if (!v) + return REBASE_FALSE; + else if (v >= 0) + return REBASE_TRUE; + else if (!strcmp(value, "preserve")) + return REBASE_PRESERVE; + return REBASE_INVALID; +} + +/** + * Callback for --rebase, which parses arg with parse_config_rebase(). + */ +static int parse_opt_rebase(const struct option *opt, const char *arg, int unset) +{ + enum rebase_type *value = opt->value; + + if (arg) + *value = parse_config_rebase(arg); + else + *value = unset ? REBASE_FALSE : REBASE_TRUE; + return *value == REBASE_INVALID ? -1 : 0; +} + static const char * const pull_usage[] = { N_("git pull [options] [ [...]]"), NULL @@ -24,7 +63,8 @@ static const char * const pull_usage[] = { static int opt_verbosity; static struct strbuf opt_progress = STRBUF_INIT; -/* Options passed to git-merge */ +/* Options passed to git-merge or git-rebase */ +static enum rebase_type opt_rebase; static struct strbuf opt_diffstat = STRBUF_INIT; static struct strbuf opt_log = STRBUF_INIT; static struct strbuf opt_squash = STRBUF_INIT; @@ -58,8 +98,12 @@ static struct option pull_options[] = { N_("force progress reporting"), PARSE_OPT_NOARG, parse_opt_pass_strbuf}, - /* Options passed to git-merge */ + /* Options passed to git-merge or git-rebase */ OPT_GROUP(N_("Options related to merging")), + { OPTION_CALLBACK, 'r', "rebase", &opt_rebase, + N_("false|true|preserve"), + N_("incorporate changes by rebasing rather than merging"), + PARSE_OPT_OPTARG, parse_opt_rebase }, { OPTION_CALLBACK, 'n', NULL, &opt_diffstat, NULL, N_("do not show a diffstat at the end of the merge"), PARSE_OPT_NOARG | PARSE_OPT_NONEG, parse_opt_pass_strbuf }, @@ -448,11 +492,194 @@ static int run_merge(void) return ret; } +/** + * Returns remote's upstream branch for the current branch. If remote is NULL, + * the current branch's configured default remote is used. Returns NULL if + * `remote` does not name a valid remote, HEAD does not point to a branch, + * remote is not the branch's configured remote or the branch does not have any + * configured upstream branch. + */ +static char *get_upstream_branch(const char *remote) +{ + struct remote *rm; + struct branch *curr_branch; + + rm = remote_get(remote); + if (!rm) + return NULL; + + curr_branch = branch_get("HEAD"); + if (!curr_branch) + return NULL; + + if (curr_branch->remote != rm) + return NULL; + + if (!curr_branch->merge_nr) + return NULL; + + return xstrdup(curr_branch->merge[0]->dst); +} + +/** + * Derives the remote tracking branch from the remote and refspec. + * + * FIXME: The current implementation assumes the default mapping of + * refs/heads/ to refs/remotes//. + */ +static char *get_tracking_branch(const char *remote, const char *refspec) +{ + struct refspec *spec; + const char *spec_src; + char *merge_branch; + + spec = parse_fetch_refspec(1, &refspec); + spec_src = spec->src; + if (!*spec_src || !strcmp(spec_src, "HEAD")) + spec_src = "HEAD"; + else if (skip_prefix(spec_src, "heads/", &spec_src)) + ; + else if (skip_prefix(spec_src, "refs/heads/", &spec_src)) + ; + else if (starts_with(spec_src, "refs/") || + starts_with(spec_src, "tags/") || + starts_with(spec_src, "remotes/")) + spec_src = ""; + + if (*spec_src) { + if (!strcmp(remote, ".")) + merge_branch = mkpathdup("refs/heads/%s", spec_src); + else + merge_branch = mkpathdup("refs/remotes/%s/%s", remote, spec_src); + } else + merge_branch = NULL; + + free_refspec(1, spec); + return merge_branch; +} + +/** + * Given the repo and refspecs, sets fork_point to the point at which the + * current branch forked from its remote tracking branch. Returns 0 on success, + * -1 on failure. + */ +static int get_rebase_fork_point(unsigned char fork_point[GIT_SHA1_RAWSZ], + const char *repo, const char *refspec) +{ + int ret; + struct branch *curr_branch; + char *remote_branch; + struct child_process cp = CHILD_PROCESS_INIT; + struct strbuf sb = STRBUF_INIT; + + curr_branch = branch_get("HEAD"); + if (!curr_branch) + return -1; + + if (refspec) + remote_branch = get_tracking_branch(repo, refspec); + else + remote_branch = get_upstream_branch(repo); + + if (!remote_branch) + return -1; + + argv_array_pushl(&cp.args, "merge-base", "--fork-point", + remote_branch, curr_branch->name, NULL); + cp.no_stdin = 1; + cp.no_stderr = 1; + cp.git_cmd = 1; + + ret = capture_command(&cp, &sb, GIT_SHA1_HEXSZ); + if (ret) + goto cleanup; + + ret = get_sha1_hex(sb.buf, fork_point); + if (ret) + goto cleanup; + +cleanup: + free(remote_branch); + strbuf_release(&sb); + return ret ? -1 : 0; +} + +/** + * Sets merge_base to the octopus merge base of curr_head, merge_head and + * fork_point. Returns 0 if a merge base is found, 1 otherwise. + */ +static int get_octopus_merge_base(unsigned char merge_base[GIT_SHA1_HEXSZ], + unsigned char curr_head[GIT_SHA1_RAWSZ], + unsigned char merge_head[GIT_SHA1_RAWSZ], + unsigned char fork_point[GIT_SHA1_RAWSZ]) +{ + struct commit_list *revs = NULL, *result; + + commit_list_insert(lookup_commit_reference(curr_head), &revs); + commit_list_insert(lookup_commit_reference(merge_head), &revs); + if (!is_null_sha1(fork_point)) + commit_list_insert(lookup_commit_reference(fork_point), &revs); + + result = reduce_heads(get_octopus_merge_bases(revs)); + free_commit_list(revs); + if (!result) + return 1; + + hashcpy(merge_base, result->item->object.sha1); + return 0; +} + +/** + * Given the current HEAD SHA1, the merge head returned from git-fetch and the + * fork point calculated by get_rebase_fork_point(), runs git-rebase with the + * appropriate arguments and returns its exit status. + */ +static int run_rebase(unsigned char curr_head[GIT_SHA1_RAWSZ], + unsigned char merge_head[GIT_SHA1_RAWSZ], + unsigned char fork_point[GIT_SHA1_RAWSZ]) +{ + int ret; + unsigned char oct_merge_base[GIT_SHA1_RAWSZ]; + struct argv_array args = ARGV_ARRAY_INIT; + + if (!get_octopus_merge_base(oct_merge_base, curr_head, merge_head, fork_point)) + if (!is_null_sha1(fork_point) && !hashcmp(oct_merge_base, fork_point)) + hashclr(fork_point); + + argv_array_push(&args, "rebase"); + + /* Shared options */ + argv_push_verbosity(&args); + + /* Options passed to git-rebase */ + if (opt_rebase == REBASE_PRESERVE) + argv_array_push(&args, "--preserve-merges"); + if (opt_diffstat.len) + argv_array_push(&args, opt_diffstat.buf); + argv_array_pushv(&args, opt_strategies.argv); + argv_array_pushv(&args, opt_strategy_opts.argv); + if (opt_gpg_sign.len) + argv_array_push(&args, opt_gpg_sign.buf); + + argv_array_push(&args, "--onto"); + argv_array_push(&args, sha1_to_hex(merge_head)); + + if (!is_null_sha1(fork_point)) + argv_array_push(&args, sha1_to_hex(fork_point)); + else + argv_array_push(&args, sha1_to_hex(merge_head)); + + ret = run_command_v_opt(args.argv, RUN_GIT_CMD); + argv_array_clear(&args); + return ret; +} + int cmd_pull(int argc, const char **argv, const char *prefix) { const char *repo, **refspecs; struct sha1_array merge_heads = SHA1_ARRAY_INIT; unsigned char orig_head[GIT_SHA1_RAWSZ], curr_head[GIT_SHA1_RAWSZ]; + unsigned char rebase_fork_point[GIT_SHA1_RAWSZ]; if (!getenv("_GIT_USE_BUILTIN_PULL")) { const char *path = mkpath("%s/git-pull", git_exec_path()); @@ -482,6 +709,10 @@ int cmd_pull(int argc, const char **argv, const char *prefix) if (get_sha1("HEAD", orig_head)) hashclr(orig_head); + if (opt_rebase) + if (get_rebase_fork_point(rebase_fork_point, repo, *refspecs)) + hashclr(rebase_fork_point); + if (run_fetch(repo, refspecs)) return 1; @@ -523,6 +754,10 @@ int cmd_pull(int argc, const char **argv, const char *prefix) if (merge_heads.nr > 1) die(_("Cannot merge multiple branches into empty head.")); return pull_into_void(*merge_heads.sha1, curr_head); + } else if (opt_rebase) { + if (merge_heads.nr > 1) + die(_("Cannot rebase onto multiple branches.")); + return run_rebase(curr_head, *merge_heads.sha1, rebase_fork_point); } else return run_merge(); } -- 2.1.4