[thirdparty/git.git] / builtin / rebase.c

/*
 * "git rebase" builtin command
 *
 * Copyright (c) 2018 Pratik Karki
 */

#include "builtin.h"
#include "run-command.h"
#include "exec-cmd.h"
#include "argv-array.h"
#include "dir.h"
#include "packfile.h"
#include "refs.h"
#include "quote.h"
#include "config.h"
#include "cache-tree.h"
#include "unpack-trees.h"
#include "lockfile.h"
#include "parse-options.h"
#include "commit.h"
#include "diff.h"
#include "wt-status.h"
#include "revision.h"

static char const * const builtin_rebase_usage[] = {
	N_("git rebase [-i] [options] [--exec <cmd>] [--onto <newbase>] "
		"[<upstream>] [<branch>]"),
	N_("git rebase [-i] [options] [--exec <cmd>] [--onto <newbase>] "
		"--root [<branch>]"),
	N_("git rebase --continue | --abort | --skip | --edit-todo"),
	NULL
};

static GIT_PATH_FUNC(apply_dir, "rebase-apply")
static GIT_PATH_FUNC(merge_dir, "rebase-merge")

enum rebase_type {
	REBASE_UNSPECIFIED = -1,
	REBASE_AM,
	REBASE_MERGE,
	REBASE_INTERACTIVE,
	REBASE_PRESERVE_MERGES
};

static int use_builtin_rebase(void)
{
	struct child_process cp = CHILD_PROCESS_INIT;
	struct strbuf out = STRBUF_INIT;
	int ret;

	argv_array_pushl(&cp.args,
			 "config", "--bool", "rebase.usebuiltin", NULL);
	cp.git_cmd = 1;
	if (capture_command(&cp, &out, 6)) {
		strbuf_release(&out);
		return 0;
	}

	strbuf_trim(&out);
	ret = !strcmp("true", out.buf);
	strbuf_release(&out);
	return ret;
}

static int apply_autostash(void)
{
	warning("TODO");
	return 0;
}

struct rebase_options {
	enum rebase_type type;
	const char *state_dir;
	struct commit *upstream;
	const char *upstream_name;
	const char *upstream_arg;
	char *head_name;
	struct object_id orig_head;
	struct commit *onto;
	const char *onto_name;
	const char *revisions;
	int root;
	struct commit *restrict_revision;
	int dont_finish_rebase;
	enum {
		REBASE_NO_QUIET = 1<<0,
		REBASE_VERBOSE = 1<<1,
		REBASE_DIFFSTAT = 1<<2,
		REBASE_FORCE = 1<<3,
	} flags;
	struct strbuf git_am_opt;
};

static int is_interactive(struct rebase_options *opts)
{
	return opts->type == REBASE_INTERACTIVE ||
		opts->type == REBASE_PRESERVE_MERGES;
}

/* Returns the filename prefixed by the state_dir */
static const char *state_dir_path(const char *filename, struct rebase_options *opts)
{
	static struct strbuf path = STRBUF_INIT;
	static size_t prefix_len;

	if (!prefix_len) {
		strbuf_addf(&path, "%s/", opts->state_dir);
		prefix_len = path.len;
	}

	strbuf_setlen(&path, prefix_len);
	strbuf_addstr(&path, filename);
	return path.buf;
}

static int finish_rebase(struct rebase_options *opts)
{
	struct strbuf dir = STRBUF_INIT;
	const char *argv_gc_auto[] = { "gc", "--auto", NULL };

	delete_ref(NULL, "REBASE_HEAD", NULL, REF_NO_DEREF);
	apply_autostash();
	close_all_packs(the_repository->objects);
	/*
	 * We ignore errors in 'gc --auto', since the
	 * user should see them.
	 */
	run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
	strbuf_addstr(&dir, opts->state_dir);
	remove_dir_recursively(&dir, 0);
	strbuf_release(&dir);

	return 0;
}

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 void add_var(struct strbuf *buf, const char *name, const char *value)
{
	if (!value)
		strbuf_addf(buf, "unset %s; ", name);
	else {
		strbuf_addf(buf, "%s=", name);
		sq_quote_buf(buf, value);
		strbuf_addstr(buf, "; ");
	}
}

static int run_specific_rebase(struct rebase_options *opts)
{
	const char *argv[] = { NULL, NULL };
	struct strbuf script_snippet = STRBUF_INIT;
	int status;
	const char *backend, *backend_func;

	add_var(&script_snippet, "GIT_DIR", absolute_path(get_git_dir()));
	add_var(&script_snippet, "state_dir", opts->state_dir);

	add_var(&script_snippet, "upstream_name", opts->upstream_name);
	add_var(&script_snippet, "upstream",
				 oid_to_hex(&opts->upstream->object.oid));
	add_var(&script_snippet, "head_name", opts->head_name);
	add_var(&script_snippet, "orig_head", oid_to_hex(&opts->orig_head));
	add_var(&script_snippet, "onto", oid_to_hex(&opts->onto->object.oid));
	add_var(&script_snippet, "onto_name", opts->onto_name);
	add_var(&script_snippet, "revisions", opts->revisions);
	add_var(&script_snippet, "restrict_revision", opts->restrict_revision ?
		oid_to_hex(&opts->restrict_revision->object.oid) : NULL);
	add_var(&script_snippet, "GIT_QUIET",
		opts->flags & REBASE_NO_QUIET ? "" : "t");
	add_var(&script_snippet, "git_am_opt", opts->git_am_opt.buf);
	add_var(&script_snippet, "verbose",
		opts->flags & REBASE_VERBOSE ? "t" : "");
	add_var(&script_snippet, "diffstat",
		opts->flags & REBASE_DIFFSTAT ? "t" : "");
	add_var(&script_snippet, "force_rebase",
		opts->flags & REBASE_FORCE ? "t" : "");

	switch (opts->type) {
	case REBASE_AM:
		backend = "git-rebase--am";
		backend_func = "git_rebase__am";
		break;
	case REBASE_INTERACTIVE:
		backend = "git-rebase--interactive";
		backend_func = "git_rebase__interactive";
		break;
	case REBASE_MERGE:
		backend = "git-rebase--merge";
		backend_func = "git_rebase__merge";
		break;
	case REBASE_PRESERVE_MERGES:
		backend = "git-rebase--preserve-merges";
		backend_func = "git_rebase__preserve_merges";
		break;
	default:
		BUG("Unhandled rebase type %d", opts->type);
		break;
	}

	strbuf_addf(&script_snippet,
		    ". git-sh-setup && . git-rebase--common &&"
		    " . %s && %s", backend, backend_func);
	argv[0] = script_snippet.buf;

	status = run_command_v_opt(argv, RUN_USING_SHELL);
	if (opts->dont_finish_rebase)
		; /* do nothing */
	else if (status == 0) {
		if (!file_exists(state_dir_path("stopped-sha", opts)))
			finish_rebase(opts);
	} else if (status == 2) {
		struct strbuf dir = STRBUF_INIT;

		apply_autostash();
		strbuf_addstr(&dir, opts->state_dir);
		remove_dir_recursively(&dir, 0);
		strbuf_release(&dir);
		die("Nothing to do");
	}

	strbuf_release(&script_snippet);

	return status ? -1 : 0;
}

#define GIT_REFLOG_ACTION_ENVIRONMENT "GIT_REFLOG_ACTION"

static int reset_head(struct object_id *oid, const char *action,
		      const char *switch_to_branch, int detach_head)
{
	struct object_id head_oid;
	struct tree_desc desc;
	struct lock_file lock = LOCK_INIT;
	struct unpack_trees_options unpack_tree_opts;
	struct tree *tree;
	const char *reflog_action;
	struct strbuf msg = STRBUF_INIT;
	size_t prefix_len;
	struct object_id *orig = NULL, oid_orig,
		*old_orig = NULL, oid_old_orig;
	int ret = 0;

	if (hold_locked_index(&lock, LOCK_REPORT_ON_ERROR) < 0)
		return -1;

	if (!oid) {
		if (get_oid("HEAD", &head_oid)) {
			rollback_lock_file(&lock);
			return error(_("could not determine HEAD revision"));
		}
		oid = &head_oid;
	}

	memset(&unpack_tree_opts, 0, sizeof(unpack_tree_opts));
	setup_unpack_trees_porcelain(&unpack_tree_opts, action);
	unpack_tree_opts.head_idx = 1;
	unpack_tree_opts.src_index = the_repository->index;
	unpack_tree_opts.dst_index = the_repository->index;
	unpack_tree_opts.fn = oneway_merge;
	unpack_tree_opts.update = 1;
	unpack_tree_opts.merge = 1;
	if (!detach_head)
		unpack_tree_opts.reset = 1;

	if (read_index_unmerged(the_repository->index) < 0) {
		rollback_lock_file(&lock);
		return error(_("could not read index"));
	}

	if (!fill_tree_descriptor(&desc, oid)) {
		error(_("failed to find tree of %s"), oid_to_hex(oid));
		rollback_lock_file(&lock);
		free((void *)desc.buffer);
		return -1;
	}

	if (unpack_trees(1, &desc, &unpack_tree_opts)) {
		rollback_lock_file(&lock);
		free((void *)desc.buffer);
		return -1;
	}

	tree = parse_tree_indirect(oid);
	prime_cache_tree(the_repository->index, tree);

	if (write_locked_index(the_repository->index, &lock, COMMIT_LOCK) < 0)
		ret = error(_("could not write index"));
	free((void *)desc.buffer);

	if (ret)
		return ret;

	reflog_action = getenv(GIT_REFLOG_ACTION_ENVIRONMENT);
	strbuf_addf(&msg, "%s: ", reflog_action ? reflog_action : "rebase");
	prefix_len = msg.len;

	if (!get_oid("ORIG_HEAD", &oid_old_orig))
		old_orig = &oid_old_orig;
	if (!get_oid("HEAD", &oid_orig)) {
		orig = &oid_orig;
		strbuf_addstr(&msg, "updating ORIG_HEAD");
		update_ref(msg.buf, "ORIG_HEAD", orig, old_orig, 0,
			   UPDATE_REFS_MSG_ON_ERR);
	} else if (old_orig)
		delete_ref(NULL, "ORIG_HEAD", old_orig, 0);
	strbuf_setlen(&msg, prefix_len);
	strbuf_addstr(&msg, "updating HEAD");
	if (!switch_to_branch)
		ret = update_ref(msg.buf, "HEAD", oid, orig, REF_NO_DEREF,
				 UPDATE_REFS_MSG_ON_ERR);
	else {
		ret = create_symref("HEAD", switch_to_branch, msg.buf);
		if (!ret)
			ret = update_ref(msg.buf, "HEAD", oid, NULL, 0,
					 UPDATE_REFS_MSG_ON_ERR);
	}

	strbuf_release(&msg);
	return ret;
}

static int rebase_config(const char *var, const char *value, void *data)
{
	struct rebase_options *opts = data;

	if (!strcmp(var, "rebase.stat")) {
		if (git_config_bool(var, value))
			opts->flags |= REBASE_DIFFSTAT;
		else
			opts->flags &= !REBASE_DIFFSTAT;
		return 0;
	}

	return git_default_config(var, value, data);
}

/*
 * Determines whether the commits in from..to are linear, i.e. contain
 * no merge commits. This function *expects* `from` to be an ancestor of
 * `to`.
 */
static int is_linear_history(struct commit *from, struct commit *to)
{
	while (to && to != from) {
		parse_commit(to);
		if (!to->parents)
			return 1;
		if (to->parents->next)
			return 0;
		to = to->parents->item;
	}
	return 1;
}

static int can_fast_forward(struct commit *onto, struct object_id *head_oid,
			    struct object_id *merge_base)
{
	struct commit *head = lookup_commit(the_repository, head_oid);
	struct commit_list *merge_bases;
	int res;

	if (!head)
		return 0;

	merge_bases = get_merge_bases(onto, head);
	if (merge_bases && !merge_bases->next) {
		oidcpy(merge_base, &merge_bases->item->object.oid);
		res = !oidcmp(merge_base, &onto->object.oid);
	} else {
		oidcpy(merge_base, &null_oid);
		res = 0;
	}
	free_commit_list(merge_bases);
	return res && is_linear_history(onto, head);
}

int cmd_rebase(int argc, const char **argv, const char *prefix)
{
	struct rebase_options options = {
		.type = REBASE_UNSPECIFIED,
		.flags = REBASE_NO_QUIET,
		.git_am_opt = STRBUF_INIT,
	};
	const char *branch_name;
	int ret, flags;
	int ok_to_skip_pre_rebase = 0;
	struct strbuf msg = STRBUF_INIT;
	struct strbuf revisions = STRBUF_INIT;
	struct object_id merge_base;
	struct option builtin_rebase_options[] = {
		OPT_STRING(0, "onto", &options.onto_name,
			   N_("revision"),
			   N_("rebase onto given branch instead of upstream")),
		OPT_BOOL(0, "no-verify", &ok_to_skip_pre_rebase,
			 N_("allow pre-rebase hook to run")),
		OPT_NEGBIT('q', "quiet", &options.flags,
			   N_("be quiet. implies --no-stat"),
			   REBASE_NO_QUIET| REBASE_VERBOSE | REBASE_DIFFSTAT),
		OPT_BIT('v', "verbose", &options.flags,
			N_("display a diffstat of what changed upstream"),
			REBASE_NO_QUIET | REBASE_VERBOSE | REBASE_DIFFSTAT),
		{OPTION_NEGBIT, 'n', "no-stat", &options.flags, NULL,
			N_("do not show diffstat of what changed upstream"),
			PARSE_OPT_NOARG, NULL, REBASE_DIFFSTAT },
		OPT_BIT('f', "force-rebase", &options.flags,
			N_("cherry-pick all commits, even if unchanged"),
			REBASE_FORCE),
		OPT_BIT(0, "no-ff", &options.flags,
			N_("cherry-pick all commits, even if unchanged"),
			REBASE_FORCE),
		OPT_END(),
	};

	/*
	 * NEEDSWORK: Once the builtin rebase has been tested enough
	 * and git-legacy-rebase.sh is retired to contrib/, this preamble
	 * can be removed.
	 */

	if (!use_builtin_rebase()) {
		const char *path = mkpath("%s/git-legacy-rebase",
					  git_exec_path());

		if (sane_execvp(path, (char **)argv) < 0)
			die_errno(_("could not exec %s"), path);
		else
			BUG("sane_execvp() returned???");
	}

	if (argc == 2 && !strcmp(argv[1], "-h"))
		usage_with_options(builtin_rebase_usage,
				   builtin_rebase_options);

	prefix = setup_git_directory();
	trace_repo_setup(prefix);
	setup_work_tree();

	git_config(rebase_config, &options);

	argc = parse_options(argc, argv, prefix,
			     builtin_rebase_options,
			     builtin_rebase_usage, 0);

	if (argc > 2)
		usage_with_options(builtin_rebase_usage,
				   builtin_rebase_options);

	if (!(options.flags & REBASE_NO_QUIET))
		strbuf_addstr(&options.git_am_opt, " -q");

	switch (options.type) {
	case REBASE_MERGE:
	case REBASE_INTERACTIVE:
	case REBASE_PRESERVE_MERGES:
		options.state_dir = merge_dir();
		break;
	case REBASE_AM:
		options.state_dir = apply_dir();
		break;
	default:
		/* the default rebase backend is `--am` */
		options.type = REBASE_AM;
		options.state_dir = apply_dir();
		break;
	}

	if (!options.root) {
		if (argc < 1)
			die("TODO: handle @{upstream}");
		else {
			options.upstream_name = argv[0];
			argc--;
			argv++;
			if (!strcmp(options.upstream_name, "-"))
				options.upstream_name = "@{-1}";
		}
		options.upstream = peel_committish(options.upstream_name);
		if (!options.upstream)
			die(_("invalid upstream '%s'"), options.upstream_name);
		options.upstream_arg = options.upstream_name;
	} else
		die("TODO: upstream for --root");

	/* Make sure the branch to rebase onto is valid. */
	if (!options.onto_name)
		options.onto_name = options.upstream_name;
	if (strstr(options.onto_name, "...")) {
		if (get_oid_mb(options.onto_name, &merge_base) < 0)
			die(_("'%s': need exactly one merge base"),
			    options.onto_name);
		options.onto = lookup_commit_or_die(&merge_base,
						    options.onto_name);
	} else {
		options.onto = peel_committish(options.onto_name);
		if (!options.onto)
			die(_("Does not point to a valid commit '%s'"),
				options.onto_name);
	}

	/*
	 * If the branch to rebase is given, that is the branch we will rebase
	 * branch_name -- branch/commit being rebased, or
	 * 		  HEAD (already detached)
	 * orig_head -- commit object name of tip of the branch before rebasing
	 * head_name -- refs/heads/<that-branch> or "detached HEAD"
	 */
	if (argc > 0)
		 die("TODO: handle switch_to");
	else {
		/* Do not need to switch branches, we are already on it. */
		options.head_name =
			xstrdup_or_null(resolve_ref_unsafe("HEAD", 0, NULL,
					 &flags));
		if (!options.head_name)
			die(_("No such ref: %s"), "HEAD");
		if (flags & REF_ISSYMREF) {
			if (!skip_prefix(options.head_name,
					 "refs/heads/", &branch_name))
				branch_name = options.head_name;

		} else {
			options.head_name = xstrdup("detached HEAD");
			branch_name = "HEAD";
		}
		if (get_oid("HEAD", &options.orig_head))
			die(_("Could not resolve HEAD to a revision"));
	}

	if (read_index(the_repository->index) < 0)
		die(_("could not read index"));

	if (require_clean_work_tree("rebase",
				    _("Please commit or stash them."), 1, 1)) {
		ret = 1;
		goto cleanup;
	}

	/*
	 * Now we are rebasing commits upstream..orig_head (or with --root,
	 * everything leading up to orig_head) on top of onto.
	 */

	/*
	 * Check if we are already based on onto with linear history,
	 * but this should be done only when upstream and onto are the same
	 * and if this is not an interactive rebase.
	 */
	if (can_fast_forward(options.onto, &options.orig_head, &merge_base) &&
	    !is_interactive(&options) && !options.restrict_revision &&
	    !oidcmp(&options.upstream->object.oid, &options.onto->object.oid)) {
		int flag;

		if (!(options.flags & REBASE_FORCE)) {
			if (!(options.flags & REBASE_NO_QUIET))
				; /* be quiet */
			else if (!strcmp(branch_name, "HEAD") &&
				 resolve_ref_unsafe("HEAD", 0, NULL, &flag))
				puts(_("HEAD is up to date."));
			else
				printf(_("Current branch %s is up to date.\n"),
				       branch_name);
			ret = !!finish_rebase(&options);
			goto cleanup;
		} else if (!(options.flags & REBASE_NO_QUIET))
			; /* be quiet */
		else if (!strcmp(branch_name, "HEAD") &&
			 resolve_ref_unsafe("HEAD", 0, NULL, &flag))
			puts(_("HEAD is up to date, rebase forced."));
		else
			printf(_("Current branch %s is up to date, rebase "
				 "forced.\n"), branch_name);
	}

	/* If a hook exists, give it a chance to interrupt*/
	if (!ok_to_skip_pre_rebase &&
	    run_hook_le(NULL, "pre-rebase", options.upstream_arg,
			argc ? argv[0] : NULL, NULL))
		die(_("The pre-rebase hook refused to rebase."));

	if (options.flags & REBASE_DIFFSTAT) {
		struct diff_options opts;

		if (options.flags & REBASE_VERBOSE)
			printf(_("Changes from %s to %s:\n"),
				oid_to_hex(&merge_base),
				oid_to_hex(&options.onto->object.oid));

		/* We want color (if set), but no pager */
		diff_setup(&opts);
		opts.stat_width = -1; /* use full terminal width */
		opts.stat_graph_width = -1; /* respect statGraphWidth config */
		opts.output_format |=
			DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
		opts.detect_rename = DIFF_DETECT_RENAME;
		diff_setup_done(&opts);
		diff_tree_oid(&merge_base, &options.onto->object.oid,
			      "", &opts);
		diffcore_std(&opts);
		diff_flush(&opts);
	}

	/* Detach HEAD and reset the tree */
	if (options.flags & REBASE_NO_QUIET)
		printf(_("First, rewinding head to replay your work on top of "
			 "it...\n"));

	strbuf_addf(&msg, "rebase: checkout %s", options.onto_name);
	if (reset_head(&options.onto->object.oid, "checkout", NULL, 1))
		die(_("Could not detach HEAD"));
	strbuf_release(&msg);

	strbuf_addf(&revisions, "%s..%s",
		    options.root ? oid_to_hex(&options.onto->object.oid) :
		    (options.restrict_revision ?
		     oid_to_hex(&options.restrict_revision->object.oid) :
		     oid_to_hex(&options.upstream->object.oid)),
		    oid_to_hex(&options.orig_head));

	options.revisions = revisions.buf;

	ret = !!run_specific_rebase(&options);

cleanup:
	strbuf_release(&revisions);
	free(options.head_name);
	return ret;
}
Commit	Line	Data
55071ea2 PK	1	/*
	2	* "git rebase" builtin command
	3	*
	4	* Copyright (c) 2018 Pratik Karki
	5	*/
	6
	7	#include "builtin.h"
	8	#include "run-command.h"
	9	#include "exec-cmd.h"
	10	#include "argv-array.h"
	11	#include "dir.h"
ac7f467f PK	12	#include "packfile.h"
	13	#include "refs.h"
	14	#include "quote.h"
	15	#include "config.h"
	16	#include "cache-tree.h"
	17	#include "unpack-trees.h"
	18	#include "lockfile.h"
f28d40d3	19	#include "parse-options.h"
075bc852	20	#include "commit.h"
bff014da	21	#include "diff.h"
e0333e5c	22	#include "wt-status.h"
9a48a615	23	#include "revision.h"
f28d40d3 PK	24
	25	static char const * const builtin_rebase_usage[] = {
	26	N_("git rebase [-i] [options] [--exec <cmd>] [--onto <newbase>] "
	27	"[<upstream>] [<branch>]"),
	28	N_("git rebase [-i] [options] [--exec <cmd>] [--onto <newbase>] "
	29	"--root [<branch>]"),
	30	N_("git rebase --continue \| --abort \| --skip \| --edit-todo"),
	31	NULL
	32	};
ac7f467f PK	33
	34	static GIT_PATH_FUNC(apply_dir, "rebase-apply")
	35	static GIT_PATH_FUNC(merge_dir, "rebase-merge")
	36
	37	enum rebase_type {
	38	REBASE_UNSPECIFIED = -1,
	39	REBASE_AM,
	40	REBASE_MERGE,
	41	REBASE_INTERACTIVE,
	42	REBASE_PRESERVE_MERGES
	43	};
55071ea2 PK	44
	45	static int use_builtin_rebase(void)
	46	{
	47	struct child_process cp = CHILD_PROCESS_INIT;
	48	struct strbuf out = STRBUF_INIT;
	49	int ret;
	50
	51	argv_array_pushl(&cp.args,
	52	"config", "--bool", "rebase.usebuiltin", NULL);
	53	cp.git_cmd = 1;
	54	if (capture_command(&cp, &out, 6)) {
	55	strbuf_release(&out);
	56	return 0;
	57	}
	58
	59	strbuf_trim(&out);
	60	ret = !strcmp("true", out.buf);
	61	strbuf_release(&out);
	62	return ret;
	63	}
	64
ac7f467f PK	65	static int apply_autostash(void)
	66	{
	67	warning("TODO");
	68	return 0;
	69	}
	70
	71	struct rebase_options {
	72	enum rebase_type type;
	73	const char *state_dir;
	74	struct commit *upstream;
	75	const char *upstream_name;
06e4775a	76	const char *upstream_arg;
ac7f467f PK	77	char *head_name;
	78	struct object_id orig_head;
	79	struct commit *onto;
	80	const char *onto_name;
	81	const char *revisions;
	82	int root;
	83	struct commit *restrict_revision;
	84	int dont_finish_rebase;
b4c8eb02 PK	85	enum {
b4c8eb02 PK	86	REBASE_NO_QUIET = 1<<0,
bff014da PK	87	REBASE_VERBOSE = 1<<1,
bff014da PK	88	REBASE_DIFFSTAT = 1<<2,
1ed9c14f	89	REBASE_FORCE = 1<<3,
b4c8eb02 PK	90	} flags;
b4c8eb02 PK	91	struct strbuf git_am_opt;
ac7f467f PK	92	};
ac7f467f PK	93
9a48a615 PK	94	static int is_interactive(struct rebase_options *opts)
	95	{
	96	return opts->type == REBASE_INTERACTIVE \|\|
	97	opts->type == REBASE_PRESERVE_MERGES;
	98	}
	99
ac7f467f PK	100	/* Returns the filename prefixed by the state_dir */
	101	static const char state_dir_path(const char filename, struct rebase_options *opts)
	102	{
	103	static struct strbuf path = STRBUF_INIT;
	104	static size_t prefix_len;
	105
	106	if (!prefix_len) {
	107	strbuf_addf(&path, "%s/", opts->state_dir);
	108	prefix_len = path.len;
	109	}
	110
	111	strbuf_setlen(&path, prefix_len);
	112	strbuf_addstr(&path, filename);
	113	return path.buf;
	114	}
	115
	116	static int finish_rebase(struct rebase_options *opts)
	117	{
	118	struct strbuf dir = STRBUF_INIT;
	119	const char *argv_gc_auto[] = { "gc", "--auto", NULL };
	120
	121	delete_ref(NULL, "REBASE_HEAD", NULL, REF_NO_DEREF);
	122	apply_autostash();
	123	close_all_packs(the_repository->objects);
	124	/*
	125	* We ignore errors in 'gc --auto', since the
	126	* user should see them.
	127	*/
	128	run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
	129	strbuf_addstr(&dir, opts->state_dir);
	130	remove_dir_recursively(&dir, 0);
	131	strbuf_release(&dir);
	132
	133	return 0;
	134	}
	135
	136	static struct commit peel_committish(const char name)
	137	{
	138	struct object *obj;
	139	struct object_id oid;
	140
	141	if (get_oid(name, &oid))
	142	return NULL;
	143	obj = parse_object(the_repository, &oid);
	144	return (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
	145	}
	146
	147	static void add_var(struct strbuf buf, const char name, const char *value)
	148	{
	149	if (!value)
	150	strbuf_addf(buf, "unset %s; ", name);
	151	else {
	152	strbuf_addf(buf, "%s=", name);
	153	sq_quote_buf(buf, value);
	154	strbuf_addstr(buf, "; ");
	155	}
	156	}
	157
	158	static int run_specific_rebase(struct rebase_options *opts)
	159	{
	160	const char *argv[] = { NULL, NULL };
	161	struct strbuf script_snippet = STRBUF_INIT;
	162	int status;
	163	const char backend, backend_func;
164
165	add_var(&script_snippet, "GIT_DIR", absolute_path(get_git_dir()));
166	add_var(&script_snippet, "state_dir", opts->state_dir);
167
168	add_var(&script_snippet, "upstream_name", opts->upstream_name);
169	add_var(&script_snippet, "upstream",
170	oid_to_hex(&opts->upstream->object.oid));
171	add_var(&script_snippet, "head_name", opts->head_name);
172	add_var(&script_snippet, "orig_head", oid_to_hex(&opts->orig_head));
173	add_var(&script_snippet, "onto", oid_to_hex(&opts->onto->object.oid));
174	add_var(&script_snippet, "onto_name", opts->onto_name);
175	add_var(&script_snippet, "revisions", opts->revisions);
176	add_var(&script_snippet, "restrict_revision", opts->restrict_revision ?
177	oid_to_hex(&opts->restrict_revision->object.oid) : NULL);
b4c8eb02 PK	178	add_var(&script_snippet, "GIT_QUIET",
	179	opts->flags & REBASE_NO_QUIET ? "" : "t");
	180	add_var(&script_snippet, "git_am_opt", opts->git_am_opt.buf);
bff014da PK	181	add_var(&script_snippet, "verbose",
	182	opts->flags & REBASE_VERBOSE ? "t" : "");
	183	add_var(&script_snippet, "diffstat",
	184	opts->flags & REBASE_DIFFSTAT ? "t" : "");
1ed9c14f PK	185	add_var(&script_snippet, "force_rebase",
1ed9c14f PK	186	opts->flags & REBASE_FORCE ? "t" : "");
ac7f467f PK	187
	188	switch (opts->type) {
	189	case REBASE_AM:
	190	backend = "git-rebase--am";
	191	backend_func = "git_rebase__am";
	192	break;
	193	case REBASE_INTERACTIVE:
	194	backend = "git-rebase--interactive";
	195	backend_func = "git_rebase__interactive";
	196	break;
	197	case REBASE_MERGE:
	198	backend = "git-rebase--merge";
	199	backend_func = "git_rebase__merge";
	200	break;
	201	case REBASE_PRESERVE_MERGES:
	202	backend = "git-rebase--preserve-merges";
	203	backend_func = "git_rebase__preserve_merges";
	204	break;
	205	default:
	206	BUG("Unhandled rebase type %d", opts->type);
	207	break;
	208	}
	209
	210	strbuf_addf(&script_snippet,
	211	". git-sh-setup && . git-rebase--common &&"
	212	" . %s && %s", backend, backend_func);
	213	argv[0] = script_snippet.buf;
	214
	215	status = run_command_v_opt(argv, RUN_USING_SHELL);
	216	if (opts->dont_finish_rebase)
	217	; /* do nothing */
	218	else if (status == 0) {
	219	if (!file_exists(state_dir_path("stopped-sha", opts)))
	220	finish_rebase(opts);
	221	} else if (status == 2) {
	222	struct strbuf dir = STRBUF_INIT;
	223
	224	apply_autostash();
	225	strbuf_addstr(&dir, opts->state_dir);
	226	remove_dir_recursively(&dir, 0);
	227	strbuf_release(&dir);
	228	die("Nothing to do");
	229	}
	230
	231	strbuf_release(&script_snippet);
	232
	233	return status ? -1 : 0;
	234	}
	235
	236	#define GIT_REFLOG_ACTION_ENVIRONMENT "GIT_REFLOG_ACTION"
	237
	238	static int reset_head(struct object_id oid, const char action,
	239	const char *switch_to_branch, int detach_head)
	240	{
	241	struct object_id head_oid;
	242	struct tree_desc desc;
	243	struct lock_file lock = LOCK_INIT;
	244	struct unpack_trees_options unpack_tree_opts;
	245	struct tree *tree;
	246	const char *reflog_action;
	247	struct strbuf msg = STRBUF_INIT;
	248	size_t prefix_len;
	249	struct object_id *orig = NULL, oid_orig,
	250	*old_orig = NULL, oid_old_orig;
251	int ret = 0;
252
253	if (hold_locked_index(&lock, LOCK_REPORT_ON_ERROR) < 0)
254	return -1;
255
256	if (!oid) {
257	if (get_oid("HEAD", &head_oid)) {
258	rollback_lock_file(&lock);
259	return error(_("could not determine HEAD revision"));
260	}
261	oid = &head_oid;
262	}
263
264	memset(&unpack_tree_opts, 0, sizeof(unpack_tree_opts));
265	setup_unpack_trees_porcelain(&unpack_tree_opts, action);
266	unpack_tree_opts.head_idx = 1;
267	unpack_tree_opts.src_index = the_repository->index;
268	unpack_tree_opts.dst_index = the_repository->index;
269	unpack_tree_opts.fn = oneway_merge;
270	unpack_tree_opts.update = 1;
271	unpack_tree_opts.merge = 1;
272	if (!detach_head)
273	unpack_tree_opts.reset = 1;
274
275	if (read_index_unmerged(the_repository->index) < 0) {
276	rollback_lock_file(&lock);
277	return error(_("could not read index"));
278	}
279
280	if (!fill_tree_descriptor(&desc, oid)) {
281	error(_("failed to find tree of %s"), oid_to_hex(oid));
282	rollback_lock_file(&lock);
283	free((void *)desc.buffer);
284	return -1;
285	}
286
287	if (unpack_trees(1, &desc, &unpack_tree_opts)) {
288	rollback_lock_file(&lock);
289	free((void *)desc.buffer);
290	return -1;
291	}
292
293	tree = parse_tree_indirect(oid);
294	prime_cache_tree(the_repository->index, tree);
295
296	if (write_locked_index(the_repository->index, &lock, COMMIT_LOCK) < 0)
297	ret = error(_("could not write index"));
298	free((void *)desc.buffer);
299
300	if (ret)
301	return ret;
302
303	reflog_action = getenv(GIT_REFLOG_ACTION_ENVIRONMENT);
304	strbuf_addf(&msg, "%s: ", reflog_action ? reflog_action : "rebase");
305	prefix_len = msg.len;
306
307	if (!get_oid("ORIG_HEAD", &oid_old_orig))
308	old_orig = &oid_old_orig;
309	if (!get_oid("HEAD", &oid_orig)) {
310	orig = &oid_orig;
311	strbuf_addstr(&msg, "updating ORIG_HEAD");
312	update_ref(msg.buf, "ORIG_HEAD", orig, old_orig, 0,
313	UPDATE_REFS_MSG_ON_ERR);
314	} else if (old_orig)
315	delete_ref(NULL, "ORIG_HEAD", old_orig, 0);
316	strbuf_setlen(&msg, prefix_len);
317	strbuf_addstr(&msg, "updating HEAD");
318	if (!switch_to_branch)
319	ret = update_ref(msg.buf, "HEAD", oid, orig, REF_NO_DEREF,
320	UPDATE_REFS_MSG_ON_ERR);
321	else {
322	ret = create_symref("HEAD", switch_to_branch, msg.buf);
323	if (!ret)
324	ret = update_ref(msg.buf, "HEAD", oid, NULL, 0,
325	UPDATE_REFS_MSG_ON_ERR);
326	}
327
328	strbuf_release(&msg);
329	return ret;
330	}
331
bff014da PK	332	static int rebase_config(const char var, const char value, void *data)
	333	{
	334	struct rebase_options *opts = data;
	335
	336	if (!strcmp(var, "rebase.stat")) {
	337	if (git_config_bool(var, value))
	338	opts->flags \|= REBASE_DIFFSTAT;
	339	else
	340	opts->flags &= !REBASE_DIFFSTAT;
	341	return 0;
	342	}
	343
	344	return git_default_config(var, value, data);
	345	}
	346
9a48a615 PK	347	/*
	348	* Determines whether the commits in from..to are linear, i.e. contain
	349	* no merge commits. This function expects `from` to be an ancestor of
	350	* `to`.
	351	*/
	352	static int is_linear_history(struct commit from, struct commit to)
	353	{
	354	while (to && to != from) {
	355	parse_commit(to);
	356	if (!to->parents)
	357	return 1;
	358	if (to->parents->next)
	359	return 0;
	360	to = to->parents->item;
	361	}
	362	return 1;
	363	}
	364
	365	static int can_fast_forward(struct commit onto, struct object_id head_oid,
	366	struct object_id *merge_base)
	367	{
	368	struct commit *head = lookup_commit(the_repository, head_oid);
	369	struct commit_list *merge_bases;
	370	int res;
	371
	372	if (!head)
	373	return 0;
	374
	375	merge_bases = get_merge_bases(onto, head);
	376	if (merge_bases && !merge_bases->next) {
	377	oidcpy(merge_base, &merge_bases->item->object.oid);
	378	res = !oidcmp(merge_base, &onto->object.oid);
	379	} else {
	380	oidcpy(merge_base, &null_oid);
	381	res = 0;
	382	}
	383	free_commit_list(merge_bases);
	384	return res && is_linear_history(onto, head);
	385	}
	386
55071ea2 PK	387	int cmd_rebase(int argc, const char *argv, const char prefix)
55071ea2 PK	388	{
ac7f467f PK	389	struct rebase_options options = {
ac7f467f PK	390	.type = REBASE_UNSPECIFIED,
b4c8eb02 PK	391	.flags = REBASE_NO_QUIET,
b4c8eb02 PK	392	.git_am_opt = STRBUF_INIT,
ac7f467f PK	393	};
	394	const char *branch_name;
	395	int ret, flags;
06e4775a	396	int ok_to_skip_pre_rebase = 0;
ac7f467f PK	397	struct strbuf msg = STRBUF_INIT;
ac7f467f PK	398	struct strbuf revisions = STRBUF_INIT;
075bc852	399	struct object_id merge_base;
f28d40d3 PK	400	struct option builtin_rebase_options[] = {
	401	OPT_STRING(0, "onto", &options.onto_name,
	402	N_("revision"),
	403	N_("rebase onto given branch instead of upstream")),
06e4775a PK	404	OPT_BOOL(0, "no-verify", &ok_to_skip_pre_rebase,
06e4775a PK	405	N_("allow pre-rebase hook to run")),
b4c8eb02 PK	406	OPT_NEGBIT('q', "quiet", &options.flags,
b4c8eb02 PK	407	N_("be quiet. implies --no-stat"),
bff014da PK	408	REBASE_NO_QUIET\| REBASE_VERBOSE \| REBASE_DIFFSTAT),
	409	OPT_BIT('v', "verbose", &options.flags,
	410	N_("display a diffstat of what changed upstream"),
	411	REBASE_NO_QUIET \| REBASE_VERBOSE \| REBASE_DIFFSTAT),
	412	{OPTION_NEGBIT, 'n', "no-stat", &options.flags, NULL,
	413	N_("do not show diffstat of what changed upstream"),
	414	PARSE_OPT_NOARG, NULL, REBASE_DIFFSTAT },
1ed9c14f PK	415	OPT_BIT('f', "force-rebase", &options.flags,
	416	N_("cherry-pick all commits, even if unchanged"),
	417	REBASE_FORCE),
	418	OPT_BIT(0, "no-ff", &options.flags,
	419	N_("cherry-pick all commits, even if unchanged"),
	420	REBASE_FORCE),
f28d40d3 PK	421	OPT_END(),
f28d40d3 PK	422	};
ac7f467f	423
55071ea2 PK	424	/*
	425	* NEEDSWORK: Once the builtin rebase has been tested enough
	426	* and git-legacy-rebase.sh is retired to contrib/, this preamble
	427	* can be removed.
	428	*/
	429
	430	if (!use_builtin_rebase()) {
	431	const char *path = mkpath("%s/git-legacy-rebase",
	432	git_exec_path());
	433
	434	if (sane_execvp(path, (char **)argv) < 0)
	435	die_errno(_("could not exec %s"), path);
	436	else
	437	BUG("sane_execvp() returned???");
	438	}
	439
f28d40d3 PK	440	if (argc == 2 && !strcmp(argv[1], "-h"))
	441	usage_with_options(builtin_rebase_usage,
	442	builtin_rebase_options);
	443
55071ea2 PK	444	prefix = setup_git_directory();
	445	trace_repo_setup(prefix);
	446	setup_work_tree();
	447
bff014da PK	448	git_config(rebase_config, &options);
bff014da PK	449
f28d40d3 PK	450	argc = parse_options(argc, argv, prefix,
	451	builtin_rebase_options,
	452	builtin_rebase_usage, 0);
	453
	454	if (argc > 2)
	455	usage_with_options(builtin_rebase_usage,
	456	builtin_rebase_options);
ac7f467f	457
b4c8eb02 PK	458	if (!(options.flags & REBASE_NO_QUIET))
	459	strbuf_addstr(&options.git_am_opt, " -q");
	460
ac7f467f PK	461	switch (options.type) {
	462	case REBASE_MERGE:
	463	case REBASE_INTERACTIVE:
	464	case REBASE_PRESERVE_MERGES:
	465	options.state_dir = merge_dir();
	466	break;
	467	case REBASE_AM:
	468	options.state_dir = apply_dir();
	469	break;
	470	default:
	471	/* the default rebase backend is `--am` */
	472	options.type = REBASE_AM;
	473	options.state_dir = apply_dir();
	474	break;
	475	}
	476
	477	if (!options.root) {
f28d40d3	478	if (argc < 1)
ac7f467f PK	479	die("TODO: handle @{upstream}");
ac7f467f PK	480	else {
f28d40d3	481	options.upstream_name = argv[0];
ac7f467f PK	482	argc--;
	483	argv++;
	484	if (!strcmp(options.upstream_name, "-"))
	485	options.upstream_name = "@{-1}";
	486	}
	487	options.upstream = peel_committish(options.upstream_name);
	488	if (!options.upstream)
	489	die(_("invalid upstream '%s'"), options.upstream_name);
06e4775a	490	options.upstream_arg = options.upstream_name;
ac7f467f PK	491	} else
	492	die("TODO: upstream for --root");
	493
	494	/* Make sure the branch to rebase onto is valid. */
	495	if (!options.onto_name)
	496	options.onto_name = options.upstream_name;
	497	if (strstr(options.onto_name, "...")) {
075bc852 PK	498	if (get_oid_mb(options.onto_name, &merge_base) < 0)
	499	die(_("'%s': need exactly one merge base"),
	500	options.onto_name);
	501	options.onto = lookup_commit_or_die(&merge_base,
	502	options.onto_name);
ac7f467f PK	503	} else {
	504	options.onto = peel_committish(options.onto_name);
	505	if (!options.onto)
	506	die(_("Does not point to a valid commit '%s'"),
	507	options.onto_name);
	508	}
	509
	510	/*
	511	* If the branch to rebase is given, that is the branch we will rebase
	512	* branch_name -- branch/commit being rebased, or
	513	* HEAD (already detached)
	514	* orig_head -- commit object name of tip of the branch before rebasing
	515	* head_name -- refs/heads/<that-branch> or "detached HEAD"
	516	*/
f28d40d3	517	if (argc > 0)
ac7f467f PK	518	die("TODO: handle switch_to");
	519	else {
	520	/* Do not need to switch branches, we are already on it. */
	521	options.head_name =
	522	xstrdup_or_null(resolve_ref_unsafe("HEAD", 0, NULL,
	523	&flags));
	524	if (!options.head_name)
	525	die(_("No such ref: %s"), "HEAD");
	526	if (flags & REF_ISSYMREF) {
	527	if (!skip_prefix(options.head_name,
	528	"refs/heads/", &branch_name))
	529	branch_name = options.head_name;
	530
	531	} else {
	532	options.head_name = xstrdup("detached HEAD");
	533	branch_name = "HEAD";
	534	}
	535	if (get_oid("HEAD", &options.orig_head))
	536	die(_("Could not resolve HEAD to a revision"));
	537	}
	538
e0333e5c PK	539	if (read_index(the_repository->index) < 0)
	540	die(_("could not read index"));
	541
	542	if (require_clean_work_tree("rebase",
	543	_("Please commit or stash them."), 1, 1)) {
	544	ret = 1;
	545	goto cleanup;
	546	}
	547
9a48a615 PK	548	/*
	549	* Now we are rebasing commits upstream..orig_head (or with --root,
	550	* everything leading up to orig_head) on top of onto.
	551	*/
	552
	553	/*
	554	* Check if we are already based on onto with linear history,
	555	* but this should be done only when upstream and onto are the same
	556	* and if this is not an interactive rebase.
	557	*/
	558	if (can_fast_forward(options.onto, &options.orig_head, &merge_base) &&
	559	!is_interactive(&options) && !options.restrict_revision &&
	560	!oidcmp(&options.upstream->object.oid, &options.onto->object.oid)) {
	561	int flag;
	562
1ed9c14f PK	563	if (!(options.flags & REBASE_FORCE)) {
	564	if (!(options.flags & REBASE_NO_QUIET))
	565	; /* be quiet */
	566	else if (!strcmp(branch_name, "HEAD") &&
	567	resolve_ref_unsafe("HEAD", 0, NULL, &flag))
	568	puts(_("HEAD is up to date."));
	569	else
	570	printf(_("Current branch %s is up to date.\n"),
	571	branch_name);
	572	ret = !!finish_rebase(&options);
	573	goto cleanup;
	574	} else if (!(options.flags & REBASE_NO_QUIET))
9a48a615 PK	575	; /* be quiet */
	576	else if (!strcmp(branch_name, "HEAD") &&
	577	resolve_ref_unsafe("HEAD", 0, NULL, &flag))
	578	puts(_("HEAD is up to date, rebase forced."));
	579	else
	580	printf(_("Current branch %s is up to date, rebase "
	581	"forced.\n"), branch_name);
	582	}
	583
06e4775a PK	584	/* If a hook exists, give it a chance to interrupt*/
	585	if (!ok_to_skip_pre_rebase &&
	586	run_hook_le(NULL, "pre-rebase", options.upstream_arg,
	587	argc ? argv[0] : NULL, NULL))
	588	die(_("The pre-rebase hook refused to rebase."));
	589
bff014da PK	590	if (options.flags & REBASE_DIFFSTAT) {
	591	struct diff_options opts;
	592
	593	if (options.flags & REBASE_VERBOSE)
	594	printf(_("Changes from %s to %s:\n"),
	595	oid_to_hex(&merge_base),
	596	oid_to_hex(&options.onto->object.oid));
	597
	598	/* We want color (if set), but no pager */
	599	diff_setup(&opts);
	600	opts.stat_width = -1; /* use full terminal width */
	601	opts.stat_graph_width = -1; /* respect statGraphWidth config */
	602	opts.output_format \|=
	603	DIFF_FORMAT_SUMMARY \| DIFF_FORMAT_DIFFSTAT;
	604	opts.detect_rename = DIFF_DETECT_RENAME;
	605	diff_setup_done(&opts);
	606	diff_tree_oid(&merge_base, &options.onto->object.oid,
	607	"", &opts);
	608	diffcore_std(&opts);
	609	diff_flush(&opts);
	610	}
	611
	612	/* Detach HEAD and reset the tree */
	613	if (options.flags & REBASE_NO_QUIET)
	614	printf(_("First, rewinding head to replay your work on top of "
	615	"it...\n"));
	616
ac7f467f PK	617	strbuf_addf(&msg, "rebase: checkout %s", options.onto_name);
	618	if (reset_head(&options.onto->object.oid, "checkout", NULL, 1))
	619	die(_("Could not detach HEAD"));
	620	strbuf_release(&msg);
	621
	622	strbuf_addf(&revisions, "%s..%s",
	623	options.root ? oid_to_hex(&options.onto->object.oid) :
	624	(options.restrict_revision ?
	625	oid_to_hex(&options.restrict_revision->object.oid) :
	626	oid_to_hex(&options.upstream->object.oid)),
	627	oid_to_hex(&options.orig_head));
	628
	629	options.revisions = revisions.buf;
	630
	631	ret = !!run_specific_rebase(&options);
	632
e0333e5c	633	cleanup:
ac7f467f PK	634	strbuf_release(&revisions);
	635	free(options.head_name);
	636	return ret;
55071ea2	637	}