checkout.c · leroysheep/MovieWebApp

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1	#define USE_THE_REPOSITORY_VARIABLE
2	#define DISABLE_SIGN_COMPARE_WARNINGS
3
4	#include "builtin.h"
5	#include "advice.h"
6	#include "branch.h"
7	#include "cache-tree.h"
8	#include "checkout.h"
9	#include "commit.h"
10	#include "config.h"
11	#include "diff.h"
12	#include "dir.h"
13	#include "environment.h"
14	#include "gettext.h"
15	#include "hex.h"
16	#include "hook.h"
17	#include "merge-ll.h"
18	#include "lockfile.h"
19	#include "mem-pool.h"
20	#include "object-file.h"
21	#include "object-name.h"
22	#include "odb.h"
23	#include "parse-options.h"
24	#include "path.h"
25	#include "preload-index.h"
26	#include "read-cache.h"
27	#include "refs.h"
28	#include "refspec.h"
29	#include "remote.h"
30	#include "repo-settings.h"
31	#include "resolve-undo.h"
32	#include "revision.h"
33	#include "run-command.h"
34	#include "sequencer.h"
35	#include "setup.h"
36	#include "sparse-index.h"
37	#include "strvec.h"
38	#include "submodule.h"
39	#include "symlinks.h"
40	#include "trace2.h"
41	#include "tree.h"
42	#include "tree-walk.h"
43	#include "unpack-trees.h"
44	#include "wt-status.h"
45	#include "xdiff-interface.h"
46	#include "entry.h"
47	#include "parallel-checkout.h"
48	#include "add-interactive.h"
49
50	struct checkout_opts {
51	int patch_mode;
52	int patch_context;
53	int patch_interhunk_context;
54	int auto_advance;
55	int quiet;
56	int merge;
57	int force;
58	int force_detach;
59	int implicit_detach;
60	int writeout_stage;
61	int overwrite_ignore;
62	int ignore_skipworktree;
63	int ignore_other_worktrees;
64	int show_progress;
65	int count_checkout_paths;
66	int overlay_mode;
67	int dwim_new_local_branch;
68	int fetch;
69	int discard_changes;
70	int accept_ref;
71	int accept_pathspec;
72	int switch_branch_doing_nothing_is_ok;
73	int only_merge_on_switching_branches;
74	int can_switch_when_in_progress;
75	int orphan_from_empty_tree;
76	int empty_pathspec_ok;
77	int checkout_index;
78	int checkout_worktree;
79	const char *ignore_unmerged_opt;
80	int ignore_unmerged;
81	int pathspec_file_nul;
82	char *pathspec_from_file;
83
84	const char *new_branch;
85	const char *new_branch_force;
86	const char *new_orphan_branch;
87	int new_branch_log;
88	enum branch_track track;
89	struct diff_options diff_options;
90	int conflict_style;
91
92	int branch_exists;
93	const char *prefix;
94	struct pathspec pathspec;
95	const char *from_treeish;
96	struct tree *source_tree;
97	};
98
99	#define CHECKOUT_OPTS_INIT { \
100	.conflict_style = -1, \
101	.merge = -1, \
102	.patch_context = -1, \
103	.patch_interhunk_context = -1, \
104	.auto_advance = 1, \
105	}
106
107	#define MERGE_WORKING_TREE_UNPACK_FAILED (-2)
108
109	struct branch_info {
110	char name; / The short name used */
111	char path; / The full name of a real branch */
112	struct commit commit; / The named commit */
113	char refname; / The full name of the ref being checked out. */
114	struct object_id oid; /* The object ID of the commit being checked out. */
115	/*
116	* if not null the branch is detached because it's already
117	* checked out in this checkout
118	*/
119	char *checkout;
120	};
121
122	static void fetch_remote_for_start_point(const char *arg, int quiet)
123	{
124	struct strbuf dst = STRBUF_INIT;
125	struct tracking tracking = { 0 };
126	struct string_list tracking_srcs = STRING_LIST_INIT_DUP;
127	struct string_list ambiguous_remotes = STRING_LIST_INIT_DUP;
128	struct child_process cmd = CHILD_PROCESS_INIT;
129	struct remote *named_remote;
130	int bare_ns;
131
132	strbuf_addf(&dst, "refs/remotes/%s", arg);
133	if (check_refname_format(dst.buf, 0))
134	die(_("cannot fetch start-point '%s': not a valid "
135	"remote-tracking name"), arg);
136
137	named_remote = remote_get(arg);
138	bare_ns = !strchr(arg, '/') \|\|
139	(named_remote && remote_is_configured(named_remote, 1));
140	if (bare_ns) {
141	char *head_path = xstrfmt("refs/remotes/%s/HEAD", arg);
142	const char *head_target =
143	refs_resolve_ref_unsafe(get_main_ref_store(the_repository),
144	head_path,
145	RESOLVE_REF_READING,
146	NULL, NULL);
147	if (head_target &&
148	starts_with(head_target, dst.buf) &&
149	head_target[dst.len] == '/') {
150	strbuf_reset(&dst);
151	strbuf_addstr(&dst, head_target);
152	bare_ns = 0;
153	}
154	free(head_path);
155	}
156
157	tracking.spec.dst = dst.buf;
158	tracking.srcs = &tracking_srcs;
159	find_tracking_remote_for_ref(&tracking, &ambiguous_remotes);
160
161	if (tracking.matches > 1) {
162	int status = die_message(_("cannot fetch start-point '%s': "
163	"fetch refspecs of multiple remotes "
164	"map to '%s'"), arg, dst.buf);
165	advise_ambiguous_fetch_refspec(dst.buf, &ambiguous_remotes);
166	exit(status);
167	}
168
169	if (!tracking.matches) {
170	if (bare_ns && named_remote &&
171	remote_is_configured(named_remote, 1)) {
172	int status = die_message(_("cannot fetch start-point '%s' "
173	"because 'refs/remotes/%s/HEAD' "
174	"does not exist."), arg, arg);
175	advise(_("To create it run\n"
176	"\n"
177	" git remote set-head %s --auto\n"), arg);
178	exit(status);
179	}
180	die(_("cannot fetch start-point '%s': no configured remote's "
181	"fetch refspec matches it"), arg);
182	}
183
184	strvec_push(&cmd.args, "fetch");
185	if (quiet)
186	strvec_push(&cmd.args, "--quiet");
187	strvec_pushl(&cmd.args, tracking.remote,
188	tracking_srcs.items[0].string, NULL);
189	cmd.git_cmd = 1;
190	if (run_command(&cmd)) {
191	if (refs_ref_exists(get_main_ref_store(the_repository), dst.buf))
192	warning(_("failed to fetch start-point '%s'; "
193	"using existing '%s'"), arg, dst.buf);
194	else
195	die(_("failed to fetch start-point '%s'"), arg);
196	}
197
198	string_list_clear(&tracking_srcs, 0);
199	string_list_clear(&ambiguous_remotes, 0);
200	strbuf_release(&dst);
201	}
202
203	static int parse_opt_checkout_track(const struct option *opt,
204	const char *arg, int unset)
205	{
206	struct checkout_opts *opts = opt->value;
207	struct string_list tokens = STRING_LIST_INIT_DUP;
208	struct string_list_item *item;
209	int saw_direct = 0;
210	int ret = 0;
211
212	opts->fetch = 0;
213	if (unset) {
214	opts->track = BRANCH_TRACK_NEVER;
215	return 0;
216	}
217	opts->track = BRANCH_TRACK_EXPLICIT;
218	if (!arg)
219	return 0;
220
221	string_list_split(&tokens, arg, ",", -1);
222	for_each_string_list_item(item, &tokens) {
223	if (!strcmp(item->string, "fetch"))
224	opts->fetch = 1;
225	else if (!strcmp(item->string, "direct"))
226	saw_direct = 1;
227	else if (!strcmp(item->string, "inherit"))
228	opts->track = BRANCH_TRACK_INHERIT;
229	else {
230	ret = error(_("option `%s' expects \"%s\", \"%s\", "
231	"or \"%s\""),
232	"--track", "direct", "inherit", "fetch");
233	goto out;
234	}
235	}
236	if (saw_direct && opts->track == BRANCH_TRACK_INHERIT)
237	ret = error(_("option `%s' cannot combine \"%s\" and \"%s\""),
238	"--track", "direct", "inherit");
239	out:
240	string_list_clear(&tokens, 0);
241	return ret;
242	}
243
244	static void branch_info_release(struct branch_info *info)
245	{
246	free(info->name);
247	free(info->path);
248	free(info->refname);
249	free(info->checkout);
250	}
251
252	static int post_checkout_hook(struct commit old_commit, struct commit new_commit,
253	int changed)
254	{
255	struct run_hooks_opt opt = RUN_HOOKS_OPT_INIT_FORCE_SERIAL;
256
257	/*
258	* "new_commit" can be NULL when checking out from the index before
259	* a commit exists.
260	*/
261	strvec_pushl(&opt.args,
262	oid_to_hex(old_commit ? &old_commit->object.oid : null_oid(the_hash_algo)),
263	oid_to_hex(new_commit ? &new_commit->object.oid : null_oid(the_hash_algo)),
264	changed ? "1" : "0",
265	NULL);
266
267	return run_hooks_opt(the_repository, "post-checkout", &opt);
268	}
269
270	/*
271	* Handle a tree object and determine if we need to recurse into the
272	* tree (READ_TREE_RECURSIVE) or skip it (0).
273	*/
274	static int try_update_sparse_directory(const struct object_id *oid,
275	struct strbuf *base,
276	const char *pathname,
277	int overlay_mode)
278	{
279	struct strbuf dirpath = STRBUF_INIT;
280	struct cache_entry *old;
281	int pos, result = READ_TREE_RECURSIVE;
282
283	if (!the_repository->index->sparse_index)
284	return result;
285
286	strbuf_addbuf(&dirpath, base);
287	strbuf_addstr(&dirpath, pathname);
288	strbuf_addch(&dirpath, '/');
289
290	pos = index_name_pos_sparse(the_repository->index,
291	dirpath.buf, dirpath.len);
292	if (pos < 0)
293	goto cleanup;
294
295	old = the_repository->index->cache[pos];
296	if (!S_ISSPARSEDIR(old->ce_mode))
297	goto cleanup;
298
299	if (oideq(oid, &old->oid)) {
300	/* Tree content already matches; no need to descend. */
301	result = 0;
302	} else if (!overlay_mode) {
303	/*
304	* In non-overlay mode (e.g., restore --staged), replace the
305	* sparse directory OID directly since files not present in
306	* the source tree should be removed anyway.
307	*/
308	oidcpy(&old->oid, oid);
309	old->ce_flags \|= CE_UPDATE;
310	result = 0;
311	}
312
313	cleanup:
314	strbuf_release(&dirpath);
315	return result;
316	}
317
318	static int update_some(const struct object_id oid, struct strbuf base,
319	const char pathname, unsigned mode, void context)
320	{
321	int len;
322	struct cache_entry *ce;
323	int pos;
324	int overlay_mode = context ? ((int )context) : 1;
325
326	if (S_ISDIR(mode))
327	return try_update_sparse_directory(oid, base, pathname,
328	overlay_mode);
329
330	len = base->len + strlen(pathname);
331	ce = make_empty_cache_entry(the_repository->index, len);
332	oidcpy(&ce->oid, oid);
333	memcpy(ce->name, base->buf, base->len);
334	memcpy(ce->name + base->len, pathname, len - base->len);
335	ce->ce_flags = create_ce_flags(0) \| CE_UPDATE;
336	ce->ce_namelen = len;
337	ce->ce_mode = create_ce_mode(mode);
338
339	/*
340	* If the entry is the same as the current index, we can leave the old
341	* entry in place. Whether it is UPTODATE or not, checkout_entry will
342	* do the right thing.
343	*/
344	pos = index_name_pos_sparse(the_repository->index, ce->name, ce->ce_namelen);
345	if (pos >= 0) {
346	struct cache_entry *old = the_repository->index->cache[pos];
347	if (ce->ce_mode == old->ce_mode &&
348	!ce_intent_to_add(old) &&
349	oideq(&ce->oid, &old->oid)) {
350	old->ce_flags \|= CE_UPDATE;
351	discard_cache_entry(ce);
352	return 0;
353	}
354	}
355
356	add_index_entry(the_repository->index, ce,
357	ADD_CACHE_OK_TO_ADD \| ADD_CACHE_OK_TO_REPLACE);
358	return 0;
359	}
360
361	static int read_tree_some(struct tree tree, const struct pathspec pathspec,
362	int overlay_mode)
363	{
364	read_tree(the_repository, tree,
365	pathspec, update_some, &overlay_mode);
366
367	/* update the index with the given tree's info
368	* for all args, expanding wildcards, and exit
369	* with any non-zero return code.
370	*/
371	return 0;
372	}
373
374	static int skip_same_name(const struct cache_entry *ce, int pos)
375	{
376	while (++pos < the_repository->index->cache_nr &&
377	!strcmp(the_repository->index->cache[pos]->name, ce->name))
378	; /* skip */
379	return pos;
380	}
381
382	static int check_stage(int stage, const struct cache_entry *ce, int pos,
383	int overlay_mode)
384	{
385	while (pos < the_repository->index->cache_nr &&
386	!strcmp(the_repository->index->cache[pos]->name, ce->name)) {
387	if (ce_stage(the_repository->index->cache[pos]) == stage)
388	return 0;
389	pos++;
390	}
391	if (!overlay_mode)
392	return 0;
393	if (stage == 2)
394	return error(_("path '%s' does not have our version"), ce->name);
395	else
396	return error(_("path '%s' does not have their version"), ce->name);
397	}
398
399	static int check_stages(unsigned stages, const struct cache_entry *ce, int pos)
400	{
401	unsigned seen = 0;
402	const char *name = ce->name;
403
404	while (pos < the_repository->index->cache_nr) {
405	ce = the_repository->index->cache[pos];
406	if (strcmp(name, ce->name))
407	break;
408	seen \|= (1 << ce_stage(ce));
409	pos++;
410	}
411	if ((stages & seen) != stages)
412	return error(_("path '%s' does not have all necessary versions"),
413	name);
414	return 0;
415	}
416
417	static int checkout_stage(int stage, const struct cache_entry *ce, int pos,
418	const struct checkout state, int nr_checkouts,
419	int overlay_mode)
420	{
421	while (pos < the_repository->index->cache_nr &&
422	!strcmp(the_repository->index->cache[pos]->name, ce->name)) {
423	if (ce_stage(the_repository->index->cache[pos]) == stage)
424	return checkout_entry(the_repository->index->cache[pos], state,
425	NULL, nr_checkouts);
426	pos++;
427	}
428	if (!overlay_mode) {
429	unlink_entry(ce, NULL);
430	return 0;
431	}
432	if (stage == 2)
433	return error(_("path '%s' does not have our version"), ce->name);
434	else
435	return error(_("path '%s' does not have their version"), ce->name);
436	}
437
438	static int checkout_merged(int pos, const struct checkout *state,
439	int nr_checkouts, struct mem_pool ce_mem_pool,
440	int conflict_style)
441	{
442	struct cache_entry *ce = the_repository->index->cache[pos];
443	const char *path = ce->name;
444	mmfile_t ancestor, ours, theirs;
445	enum ll_merge_result merge_status;
446	int status;
447	struct object_id oid;
448	mmbuffer_t result_buf;
449	struct object_id threeway[3];
450	unsigned mode = 0;
451	struct ll_merge_options ll_opts = LL_MERGE_OPTIONS_INIT;
452	int renormalize = 0;
453
454	memset(threeway, 0, sizeof(threeway));
455	while (pos < the_repository->index->cache_nr) {
456	int stage;
457	stage = ce_stage(ce);
458	if (!stage \|\| strcmp(path, ce->name))
459	break;
460	oidcpy(&threeway[stage - 1], &ce->oid);
461	if (stage == 2)
462	mode = create_ce_mode(ce->ce_mode);
463	pos++;
464	ce = the_repository->index->cache[pos];
465	}
466	if (is_null_oid(&threeway[1]) \|\| is_null_oid(&threeway[2]))
467	return error(_("path '%s' does not have necessary versions"), path);
468
469	read_mmblob(&ancestor, the_repository->objects, &threeway[0]);
470	read_mmblob(&ours, the_repository->objects, &threeway[1]);
471	read_mmblob(&theirs, the_repository->objects, &threeway[2]);
472
473	repo_config_get_bool(the_repository, "merge.renormalize", &renormalize);
474	ll_opts.renormalize = renormalize;
475	ll_opts.conflict_style = conflict_style;
476	merge_status = ll_merge(&result_buf, path, &ancestor, "base",
477	&ours, "ours", &theirs, "theirs",
478	state->istate, &ll_opts);
479	free(ancestor.ptr);
480	free(ours.ptr);
481	free(theirs.ptr);
482	if (merge_status == LL_MERGE_BINARY_CONFLICT)
483	warning("Cannot merge binary files: %s (%s vs. %s)",
484	path, "ours", "theirs");
485	if (merge_status < 0 \|\| !result_buf.ptr) {
486	free(result_buf.ptr);
487	return error(_("path '%s': cannot merge"), path);
488	}
489
490	/*
491	* NEEDSWORK:
492	* There is absolutely no reason to write this as a blob object
493	* and create a phony cache entry. This hack is primarily to get
494	* to the write_entry() machinery that massages the contents to
495	* work-tree format and writes out which only allows it for a
496	* cache entry. The code in write_entry() needs to be refactored
497	* to allow us to feed a <buffer, size, mode> instead of a cache
498	* entry. Such a refactoring would help merge_recursive as well
499	* (it also writes the merge result to the object database even
500	* when it may contain conflicts).
501	*/
502	if (odb_write_object(the_repository->objects, result_buf.ptr, result_buf.size, OBJ_BLOB, &oid))
503	die(_("Unable to add merge result for '%s'"), path);
504	free(result_buf.ptr);
505	ce = make_transient_cache_entry(mode, &oid, path, 2, ce_mem_pool);
506	if (!ce)
507	die(_("make_cache_entry failed for path '%s'"), path);
508	status = checkout_entry(ce, state, NULL, nr_checkouts);
509	return status;
510	}
511
512	static void mark_ce_for_checkout_overlay(struct cache_entry *ce,
513	char *ps_matched,
514	const struct checkout_opts *opts)
515	{
516	ce->ce_flags &= ~CE_MATCHED;
517	if (!opts->ignore_skipworktree && ce_skip_worktree(ce))
518	return;
519	if (opts->source_tree && !(ce->ce_flags & CE_UPDATE))
520	/*
521	* "git checkout tree-ish -- path", but this entry
522	* is in the original index but is not in tree-ish
523	* or does not match the pathspec; it will not be
524	* checked out to the working tree. We will not do
525	* anything to this entry at all.
526	*/
527	return;
528	/*
529	* Either this entry came from the tree-ish we are
530	* checking the paths out of, or we are checking out
531	* of the index.
532	*
533	* If it comes from the tree-ish, we already know it
534	* matches the pathspec and could just stamp
535	* CE_MATCHED to it from update_some(). But we still
536	* need ps_matched and read_tree (and
537	* eventually tree_entry_interesting) cannot fill
538	* ps_matched yet. Once it can, we can avoid calling
539	* match_pathspec() for _all_ entries when
540	* opts->source_tree != NULL.
541	*/
542	if (ce_path_match(the_repository->index, ce, &opts->pathspec, ps_matched))
543	ce->ce_flags \|= CE_MATCHED;
544	}
545
546	static void mark_ce_for_checkout_no_overlay(struct cache_entry *ce,
547	char *ps_matched,
548	const struct checkout_opts *opts)
549	{
550	ce->ce_flags &= ~CE_MATCHED;
551	if (!opts->ignore_skipworktree && ce_skip_worktree(ce))
552	return;
553	if (ce_path_match(the_repository->index, ce, &opts->pathspec, ps_matched)) {
554	ce->ce_flags \|= CE_MATCHED;
555	if (opts->source_tree && !(ce->ce_flags & CE_UPDATE))
556	/*
557	* In overlay mode, but the path is not in
558	* tree-ish, which means we should remove it
559	* from the index and the working tree.
560	*/
561	ce->ce_flags \|= CE_REMOVE \| CE_WT_REMOVE;
562	}
563	}
564
565	static int checkout_worktree(const struct checkout_opts *opts,
566	const struct branch_info *info)
567	{
568	struct checkout state = CHECKOUT_INIT;
569	int nr_checkouts = 0, nr_unmerged = 0;
570	int errs = 0;
571	int pos;
572	int pc_workers, pc_threshold;
573	struct mem_pool ce_mem_pool;
574
575	state.force = 1;
576	state.refresh_cache = 1;
577	state.istate = the_repository->index;
578
579	mem_pool_init(&ce_mem_pool, 0);
580	get_parallel_checkout_configs(&pc_workers, &pc_threshold);
581	init_checkout_metadata(&state.meta, info->refname,
582	info->commit ? &info->commit->object.oid : &info->oid,
583	NULL);
584
585	enable_delayed_checkout(&state);
586
587	if (pc_workers > 1)
588	init_parallel_checkout();
589
590	for (pos = 0; pos < the_repository->index->cache_nr; pos++) {
591	struct cache_entry *ce = the_repository->index->cache[pos];
592	if (ce->ce_flags & CE_MATCHED) {
593	if (!ce_stage(ce)) {
594	errs \|= checkout_entry(ce, &state,
595	NULL, &nr_checkouts);
596	continue;
597	}
598	if (opts->writeout_stage)
599	errs \|= checkout_stage(opts->writeout_stage,
600	ce, pos,
601	&state,
602	&nr_checkouts, opts->overlay_mode);
603	else if (opts->merge)
604	errs \|= checkout_merged(pos, &state,
605	&nr_unmerged,
606	&ce_mem_pool,
607	opts->conflict_style);
608	pos = skip_same_name(ce, pos) - 1;
609	}
610	}
611	if (pc_workers > 1)
612	errs \|= run_parallel_checkout(&state, pc_workers, pc_threshold,
613	NULL, NULL);
614	mem_pool_discard(&ce_mem_pool, should_validate_cache_entries());
615	remove_marked_cache_entries(the_repository->index, 1);
616	remove_scheduled_dirs();
617	errs \|= finish_delayed_checkout(&state, opts->show_progress);
618
619	if (opts->count_checkout_paths) {
620	if (nr_unmerged)
621	fprintf_ln(stderr, Q_("Recreated %d merge conflict",
622	"Recreated %d merge conflicts",
623	nr_unmerged),
624	nr_unmerged);
625	if (opts->source_tree)
626	fprintf_ln(stderr, Q_("Updated %d path from %s",
627	"Updated %d paths from %s",
628	nr_checkouts),
629	nr_checkouts,
630	repo_find_unique_abbrev(the_repository, &opts->source_tree->object.oid,
631	DEFAULT_ABBREV));
632	else if (!nr_unmerged \|\| nr_checkouts)
633	fprintf_ln(stderr, Q_("Updated %d path from the index",
634	"Updated %d paths from the index",
635	nr_checkouts),
636	nr_checkouts);
637	}
638
639	return errs;
640	}
641
642	static int checkout_paths(const struct checkout_opts *opts,
643	const struct branch_info *new_branch_info)
644	{
645	int pos;
646	static char *ps_matched;
647	struct object_id rev;
648	struct commit *head;
649	int errs = 0;
650	struct lock_file lock_file = LOCK_INIT;
651	int checkout_index;
652
653	trace2_cmd_mode(opts->patch_mode ? "patch" : "path");
654
655	if (opts->track != BRANCH_TRACK_UNSPECIFIED)
656	die(_("'%s' cannot be used with updating paths"), "--track");
657
658	if (opts->new_branch_log)
659	die(_("'%s' cannot be used with updating paths"), "-l");
660
661	if (opts->ignore_unmerged && opts->patch_mode)
662	die(_("'%s' cannot be used with updating paths"),
663	opts->ignore_unmerged_opt);
664
665	if (opts->force_detach)
666	die(_("'%s' cannot be used with updating paths"), "--detach");
667
668	if (opts->merge && opts->patch_mode)
669	die(_("options '%s' and '%s' cannot be used together"), "--merge", "--patch");
670
671	if (opts->ignore_unmerged && opts->merge)
672	die(_("options '%s' and '%s' cannot be used together"),
673	opts->ignore_unmerged_opt, "-m");
674
675	if (opts->new_branch)
676	die(_("Cannot update paths and switch to branch '%s' at the same time."),
677	opts->new_branch);
678
679	if (!opts->checkout_worktree && !opts->checkout_index)
680	die(_("neither '%s' or '%s' is specified"),
681	"--staged", "--worktree");
682
683	if (!opts->checkout_worktree && !opts->from_treeish)
684	die(_("'%s' must be used when '%s' is not specified"),
685	"--worktree", "--source");
686
687	/*
688	* Reject --staged option to the restore command when combined with
689	* merge-related options. Use the accept_ref flag to distinguish it
690	* from the checkout command, which does not accept --staged anyway.
691	*
692	* `restore --ours\|--theirs --worktree --staged` could mean resolving
693	* conflicted paths to one side in both the worktree and the index,
694	* but does not currently.
695	*
696	* `restore --merge\|--conflict=<style>` already recreates conflicts
697	* in both the worktree and the index, so adding --staged would be
698	* meaningless.
699	*/
700	if (!opts->accept_ref && opts->checkout_index) {
701	if (opts->writeout_stage)
702	die(_("'%s' or '%s' cannot be used with %s"),
703	"--ours", "--theirs", "--staged");
704
705	if (opts->merge)
706	die(_("'%s' or '%s' cannot be used with %s"),
707	"--merge", "--conflict", "--staged");
708	}
709
710	/*
711	* recreating unmerged index entries and writing out data from
712	* unmerged index entries would make no sense when checking out
713	* of a tree-ish.
714	*/
715	if ((opts->merge \|\| opts->writeout_stage) && opts->source_tree)
716	die(_("'%s', '%s', or '%s' cannot be used when checking out of a tree"),
717	"--merge", "--ours", "--theirs");
718
719	if (opts->patch_mode) {
720	enum add_p_mode patch_mode;
721	struct interactive_options interactive_opts = {
722	.context = opts->patch_context,
723	.interhunkcontext = opts->patch_interhunk_context,
724	.auto_advance = opts->auto_advance
725	};
726	const char *rev = new_branch_info->name;
727	char rev_oid[GIT_MAX_HEXSZ + 1];
728
729	/*
730	* Since rev can be in the form of `<a>...<b>` (which is not
731	* recognized by diff-index), we will always replace the name
732	* with the hex of the commit (whether it's in `...` form or
733	* not) for the run_add_interactive() machinery to work
734	* properly. However, there is special logic for the HEAD case
735	* so we mustn't replace that. Also, when we were given a
736	* tree-object, new_branch_info->commit would be NULL, but we
737	* do not have to do any replacement, either.
738	*/
739	if (rev && new_branch_info->commit && strcmp(rev, "HEAD"))
740	rev = oid_to_hex_r(rev_oid, &new_branch_info->commit->object.oid);
741
742	if (opts->checkout_index && opts->checkout_worktree)
743	patch_mode = ADD_P_CHECKOUT;
744	else if (opts->checkout_index && !opts->checkout_worktree)
745	patch_mode = ADD_P_RESET;
746	else if (!opts->checkout_index && opts->checkout_worktree)
747	patch_mode = ADD_P_WORKTREE;
748	else
749	BUG("either flag must have been set, worktree=%d, index=%d",
750	opts->checkout_worktree, opts->checkout_index);
751	return !!run_add_p(the_repository, patch_mode, &interactive_opts,
752	rev, &opts->pathspec, 0);
753	}
754
755	repo_hold_locked_index(the_repository, &lock_file, LOCK_DIE_ON_ERROR);
756	if (repo_read_index_preload(the_repository, &opts->pathspec, 0) < 0)
757	return error(_("index file corrupt"));
758
759	if (opts->source_tree)
760	read_tree_some(opts->source_tree, &opts->pathspec,
761	opts->overlay_mode);
762	if (opts->merge)
763	unmerge_index(the_repository->index, &opts->pathspec, CE_MATCHED);
764
765	ps_matched = xcalloc(opts->pathspec.nr, 1);
766
767	/*
768	* Make sure all pathspecs participated in locating the paths
769	* to be checked out.
770	*/
771	for (pos = 0; pos < the_repository->index->cache_nr; pos++)
772	if (opts->overlay_mode)
773	mark_ce_for_checkout_overlay(the_repository->index->cache[pos],
774	ps_matched,
775	opts);
776	else
777	mark_ce_for_checkout_no_overlay(the_repository->index->cache[pos],
778	ps_matched,
779	opts);
780
781	if (report_path_error(ps_matched, &opts->pathspec)) {
782	free(ps_matched);
783	return 1;
784	}
785	free(ps_matched);
786
787	/* Any unmerged paths? */
788	for (pos = 0; pos < the_repository->index->cache_nr; pos++) {
789	const struct cache_entry *ce = the_repository->index->cache[pos];
790	if (ce->ce_flags & CE_MATCHED) {
791	if (!ce_stage(ce))
792	continue;
793	if (opts->ignore_unmerged) {
794	if (!opts->quiet)
795	warning(_("path '%s' is unmerged"), ce->name);
796	} else if (opts->writeout_stage) {
797	errs \|= check_stage(opts->writeout_stage, ce, pos, opts->overlay_mode);
798	} else if (opts->merge) {
799	errs \|= check_stages((1<<2) \| (1<<3), ce, pos);
800	} else {
801	errs = 1;
802	error(_("path '%s' is unmerged"), ce->name);
803	}
804	pos = skip_same_name(ce, pos) - 1;
805	}
806	}
807	if (errs)
808	return 1;
809
810	/* Now we are committed to check them out */
811	if (opts->checkout_worktree)
812	errs \|= checkout_worktree(opts, new_branch_info);
813	else
814	remove_marked_cache_entries(the_repository->index, 1);
815
816	/*
817	* Allow updating the index when checking out from the index.
818	* This is to save new stat info.
819	*/
820	if (opts->checkout_worktree && !opts->checkout_index && !opts->source_tree)
821	checkout_index = 1;
822	else
823	checkout_index = opts->checkout_index;
824
825	if (checkout_index) {
826	if (write_locked_index(the_repository->index, &lock_file, COMMIT_LOCK))
827	die(_("unable to write new index file"));
828	} else {
829	/*
830	* NEEDSWORK: if --worktree is not specified, we
831	* should save stat info of checked out files in the
832	* index to avoid the next (potentially costly)
833	* refresh. But it's a bit tricker to do...
834	*/
835	rollback_lock_file(&lock_file);
836	}
837
838	refs_read_ref_full(get_main_ref_store(the_repository), "HEAD", 0,
839	&rev, NULL);
840	head = lookup_commit_reference_gently(the_repository, &rev, 1);
841
842	errs \|= post_checkout_hook(head, head, 0);
843	return errs;
844	}
845
846	static void show_local_changes(struct object *head,
847	const struct diff_options *opts)
848	{
849	struct rev_info rev;
850	/* I think we want full paths, even if we're in a subdirectory. */
851	repo_init_revisions(the_repository, &rev, NULL);
852	rev.diffopt.flags = opts->flags;
853	rev.diffopt.output_format \|= DIFF_FORMAT_NAME_STATUS;
854	rev.diffopt.flags.recursive = 1;
855	diff_setup_done(&rev.diffopt);
856	add_pending_object(&rev, head, NULL);
857	run_diff_index(&rev, 0);
858	release_revisions(&rev);
859	}
860
861	static void describe_detached_head(const char msg, struct commit commit)
862	{
863	struct strbuf sb = STRBUF_INIT;
864
865	if (!repo_parse_commit(the_repository, commit))
866	pp_commit_easy(CMIT_FMT_ONELINE, commit, &sb);
867	if (print_sha1_ellipsis()) {
868	fprintf(stderr, "%s %s... %s\n", msg,
869	repo_find_unique_abbrev(the_repository, &commit->object.oid, DEFAULT_ABBREV),
870	sb.buf);
871	} else {
872	fprintf(stderr, "%s %s %s\n", msg,
873	repo_find_unique_abbrev(the_repository, &commit->object.oid, DEFAULT_ABBREV),
874	sb.buf);
875	}
876	strbuf_release(&sb);
877	}
878
879	static int reset_tree(struct tree tree, const struct checkout_opts o,
880	int worktree, int *writeout_error,
881	struct branch_info *info)
882	{
883	struct unpack_trees_options opts;
884	struct tree_desc tree_desc;
885
886	memset(&opts, 0, sizeof(opts));
887	opts.head_idx = -1;
888	opts.update = worktree;
889	opts.skip_unmerged = !worktree;
890	opts.reset = o->force ? UNPACK_RESET_OVERWRITE_UNTRACKED :
891	UNPACK_RESET_PROTECT_UNTRACKED;
892	opts.preserve_ignored = (!o->force && !o->overwrite_ignore);
893	opts.merge = 1;
894	opts.fn = oneway_merge;
895	opts.verbose_update = o->show_progress;
896	opts.src_index = the_repository->index;
897	opts.dst_index = the_repository->index;
898	init_checkout_metadata(&opts.meta, info->refname,
899	info->commit ? &info->commit->object.oid : null_oid(the_hash_algo),
900	NULL);
901	if (repo_parse_tree(the_repository, tree) < 0)
902	return 128;
903	init_tree_desc(&tree_desc, &tree->object.oid, tree->buffer, tree->size);
904	switch (unpack_trees(1, &tree_desc, &opts)) {
905	case -2:
906	*writeout_error = 1;
907	/*
908	* We return 0 nevertheless, as the index is all right
909	* and more importantly we have made best efforts to
910	* update paths in the work tree, and we cannot revert
911	* them.
912	*/
913	/* fallthrough */
914	case 0:
915	return 0;
916	default:
917	return 128;
918	}
919	}
920
921	static void setup_branch_path(struct branch_info *branch)
922	{
923	struct strbuf buf = STRBUF_INIT;
924
925	/*
926	* If this is a ref, resolve it; otherwise, look up the OID for our
927	* expression. Failure here is okay.
928	*/
929	if (!repo_dwim_ref(the_repository, branch->name, strlen(branch->name),
930	&branch->oid, &branch->refname, 0))
931	repo_get_oid_committish(the_repository, branch->name, &branch->oid);
932
933	copy_branchname(the_repository, &buf, branch->name, INTERPRET_BRANCH_LOCAL);
934	if (strcmp(buf.buf, branch->name)) {
935	free(branch->name);
936	branch->name = xstrdup(buf.buf);
937	}
938	strbuf_splice(&buf, 0, 0, "refs/heads/", 11);
939	free(branch->path);
940	branch->path = strbuf_detach(&buf, NULL);
941	}
942
943	static void init_topts(struct unpack_trees_options *topts,
944	int show_progress, int overwrite_ignore,
945	bool quiet)
946	{
947	memset(topts, 0, sizeof(*topts));
948	topts->head_idx = -1;
949	topts->src_index = the_repository->index;
950	topts->dst_index = the_repository->index;
951
952	setup_unpack_trees_porcelain(topts, "checkout");
953
954	topts->initial_checkout = is_index_unborn(the_repository->index);
955	topts->update = 1;
956	topts->merge = 1;
957	topts->quiet = quiet;
958	topts->verbose_update = show_progress;
959	topts->fn = twoway_merge;
960	topts->preserve_ignored = !overwrite_ignore;
961	}
962
963	static int merge_working_tree(const struct checkout_opts *opts,
964	struct branch_info *old_branch_info,
965	struct branch_info *new_branch_info,
966	bool allow_autostash,
967	int *writeout_error)
968	{
969	int ret;
970	bool can_autostash = false;
971	struct lock_file lock_file = LOCK_INIT;
972	struct tree *new_tree;
973
974	repo_hold_locked_index(the_repository, &lock_file, LOCK_DIE_ON_ERROR);
975	if (repo_read_index_preload(the_repository, NULL, 0) < 0) {
976	rollback_lock_file(&lock_file);
977	return error(_("index file corrupt"));
978	}
979
980	resolve_undo_clear_index(the_repository->index);
981	if (opts->new_orphan_branch && opts->orphan_from_empty_tree) {
982	if (new_branch_info->commit)
983	BUG("'switch --orphan' should never accept a commit as starting point");
984	new_tree = repo_parse_tree_indirect(the_repository,
985	the_hash_algo->empty_tree);
986	if (!new_tree)
987	BUG("unable to read empty tree");
988	} else {
989	new_tree = repo_get_commit_tree(the_repository,
990	new_branch_info->commit);
991	if (!new_tree) {
992	rollback_lock_file(&lock_file);
993	return error(_("unable to read tree (%s)"),
994	oid_to_hex(&new_branch_info->commit->object.oid));
995	}
996	}
997	if (opts->discard_changes) {
998	ret = reset_tree(new_tree, opts, 1, writeout_error, new_branch_info);
999	if (ret) {
1000	rollback_lock_file(&lock_file);
1001	return ret;
1002	}
1003	} else {
1004	struct tree_desc trees[2];
1005	struct tree *tree;
1006	struct unpack_trees_options topts;
1007	const struct object_id *old_commit_oid;
1008
1009	refresh_index(the_repository->index, REFRESH_QUIET, NULL, NULL, NULL);
1010
1011	if (unmerged_index(the_repository->index)) {
1012	rollback_lock_file(&lock_file);
1013	error(_("you need to resolve your current index first"));
1014	return 1;
1015	}
1016
1017	if (allow_autostash)
1018	can_autostash = has_unstaged_changes(the_repository, 1) \|\|
1019	has_uncommitted_changes(the_repository, 1);
1020
1021	/* 2-way merge to the new branch */
1022	init_topts(&topts, opts->show_progress,
1023	opts->overwrite_ignore, can_autostash);
1024	init_checkout_metadata(&topts.meta, new_branch_info->refname,
1025	new_branch_info->commit ?
1026	&new_branch_info->commit->object.oid :
1027	&new_branch_info->oid, NULL);
1028
1029	old_commit_oid = old_branch_info->commit ?
1030	&old_branch_info->commit->object.oid :
1031	the_hash_algo->empty_tree;
1032	tree = repo_parse_tree_indirect(the_repository,
1033	old_commit_oid);
1034	if (!tree)
1035	die(_("unable to parse commit %s"),
1036	oid_to_hex(old_commit_oid));
1037
1038	init_tree_desc(&trees[0], &tree->object.oid,
1039	tree->buffer, tree->size);
1040	if (repo_parse_tree(the_repository, new_tree) < 0)
1041	die(NULL);
1042	tree = new_tree;
1043	init_tree_desc(&trees[1], &tree->object.oid,
1044	tree->buffer, tree->size);
1045
1046	ret = unpack_trees(2, trees, &topts);
1047	clear_unpack_trees_porcelain(&topts);
1048	if (ret == -1) {
1049	rollback_lock_file(&lock_file);
1050	return can_autostash ?
1051	MERGE_WORKING_TREE_UNPACK_FAILED : 1;
1052	}
1053	}
1054
1055	if (!cache_tree_fully_valid(the_repository->index->cache_tree))
1056	cache_tree_update(the_repository->index, WRITE_TREE_SILENT \| WRITE_TREE_REPAIR);
1057
1058	if (write_locked_index(the_repository->index, &lock_file, COMMIT_LOCK))
1059	die(_("unable to write new index file"));
1060
1061	if (!opts->discard_changes && !opts->quiet && new_branch_info->commit)
1062	show_local_changes(&new_branch_info->commit->object, &opts->diff_options);
1063
1064	return 0;
1065	}
1066
1067	static void report_tracking(struct branch_info *new_branch_info)
1068	{
1069	struct strbuf sb = STRBUF_INIT;
1070	struct branch *branch = branch_get(new_branch_info->name);
1071
1072	if (!format_tracking_info(branch, &sb, AHEAD_BEHIND_FULL, 1))
1073	return;
1074	fputs(sb.buf, stdout);
1075	strbuf_release(&sb);
1076	}
1077
1078	static void update_refs_for_switch(const struct checkout_opts *opts,
1079	struct branch_info *old_branch_info,
1080	struct branch_info *new_branch_info)
1081	{
1082	struct strbuf msg = STRBUF_INIT;
1083	const char old_desc, reflog_msg;
1084	if (opts->new_branch) {
1085	if (opts->new_orphan_branch) {
1086	enum log_refs_config log_all_ref_updates = LOG_REFS_UNSET;
1087	const char *value;
1088	char *refname;
1089
1090	if (!repo_config_get_string_tmp(the_repository, "core.logallrefupdates", &value))
1091	log_all_ref_updates = refs_parse_log_all_ref_updates_config(value);
1092
1093	refname = mkpathdup("refs/heads/%s", opts->new_orphan_branch);
1094	if (opts->new_branch_log &&
1095	!should_autocreate_reflog(log_all_ref_updates, refname)) {
1096	int ret;
1097	struct strbuf err = STRBUF_INIT;
1098
1099	ret = refs_create_reflog(get_main_ref_store(the_repository),
1100	refname, &err);
1101	if (ret) {
1102	fprintf(stderr, _("Can not do reflog for '%s': %s\n"),
1103	opts->new_orphan_branch, err.buf);
1104	strbuf_release(&err);
1105	free(refname);
1106	return;
1107	}
1108	strbuf_release(&err);
1109	}
1110	free(refname);
1111	}
1112	else
1113	create_branch(the_repository,
1114	opts->new_branch, new_branch_info->name,
1115	opts->new_branch_force ? 1 : 0,
1116	opts->new_branch_force ? 1 : 0,
1117	opts->new_branch_log,
1118	opts->quiet,
1119	opts->track,
1120	0);
1121	free(new_branch_info->name);
1122	free(new_branch_info->refname);
1123	new_branch_info->name = xstrdup(opts->new_branch);
1124	setup_branch_path(new_branch_info);
1125	}
1126
1127	old_desc = old_branch_info->name;
1128	if (!old_desc && old_branch_info->commit)
1129	old_desc = oid_to_hex(&old_branch_info->commit->object.oid);
1130
1131	reflog_msg = getenv("GIT_REFLOG_ACTION");
1132	if (!reflog_msg)
1133	strbuf_addf(&msg, "checkout: moving from %s to %s",
1134	old_desc ? old_desc : "(invalid)", new_branch_info->name);
1135	else
1136	strbuf_insertstr(&msg, 0, reflog_msg);
1137
1138	if (!strcmp(new_branch_info->name, "HEAD") && !new_branch_info->path && !opts->force_detach) {
1139	/* Nothing to do. */
1140	} else if (opts->force_detach \|\| !new_branch_info->path) { /* No longer on any branch. */
1141	refs_update_ref(get_main_ref_store(the_repository), msg.buf,
1142	"HEAD", &new_branch_info->commit->object.oid,
1143	NULL,
1144	REF_NO_DEREF, UPDATE_REFS_DIE_ON_ERR);
1145	if (!opts->quiet) {
1146	if (old_branch_info->path &&
1147	advice_enabled(ADVICE_DETACHED_HEAD) && !opts->force_detach)
1148	detach_advice(new_branch_info->name);
1149	describe_detached_head(_("HEAD is now at"), new_branch_info->commit);
1150	}
1151	} else if (new_branch_info->path) { /* Switch branches. */
1152	if (refs_update_symref(get_main_ref_store(the_repository), "HEAD", new_branch_info->path, msg.buf) < 0)
1153	die(_("unable to update HEAD"));
1154	if (!opts->quiet) {
1155	if (old_branch_info->path && !strcmp(new_branch_info->path, old_branch_info->path)) {
1156	if (opts->new_branch_force)
1157	fprintf(stderr, _("Reset branch '%s'\n"),
1158	new_branch_info->name);
1159	else
1160	fprintf(stderr, _("Already on '%s'\n"),
1161	new_branch_info->name);
1162	} else if (opts->new_branch) {
1163	if (opts->branch_exists)
1164	fprintf(stderr, _("Switched to and reset branch '%s'\n"), new_branch_info->name);
1165	else
1166	fprintf(stderr, _("Switched to a new branch '%s'\n"), new_branch_info->name);
1167	} else {
1168	fprintf(stderr, _("Switched to branch '%s'\n"),
1169	new_branch_info->name);
1170	}
1171	}
1172	if (old_branch_info->path && old_branch_info->name) {
1173	if (!refs_ref_exists(get_main_ref_store(the_repository), old_branch_info->path) && refs_reflog_exists(get_main_ref_store(the_repository), old_branch_info->path))
1174	refs_delete_reflog(get_main_ref_store(the_repository),
1175	old_branch_info->path);
1176	}
1177	}
1178	remove_branch_state(the_repository, !opts->quiet);
1179	strbuf_release(&msg);
1180	if (!opts->quiet &&
1181	!opts->force_detach &&
1182	(new_branch_info->path \|\| !strcmp(new_branch_info->name, "HEAD")))
1183	report_tracking(new_branch_info);
1184	}
1185
1186	static int add_pending_uninteresting_ref(const struct reference ref, void cb_data)
1187	{
1188	add_pending_oid(cb_data, ref->name, ref->oid, UNINTERESTING);
1189	return 0;
1190	}
1191
1192	static void describe_one_orphan(struct strbuf sb, struct commit commit)
1193	{
1194	strbuf_addstr(sb, " ");
1195	strbuf_add_unique_abbrev(sb, &commit->object.oid, DEFAULT_ABBREV);
1196	strbuf_addch(sb, ' ');
1197	if (!repo_parse_commit(the_repository, commit))
1198	pp_commit_easy(CMIT_FMT_ONELINE, commit, sb);
1199	strbuf_addch(sb, '\n');
1200	}
1201
1202	#define ORPHAN_CUTOFF 4
1203	static void suggest_reattach(struct commit commit, struct rev_info revs)
1204	{
1205	struct commit c, last = NULL;
1206	struct strbuf sb = STRBUF_INIT;
1207	int lost = 0;
1208	while ((c = get_revision(revs)) != NULL) {
1209	if (lost < ORPHAN_CUTOFF)
1210	describe_one_orphan(&sb, c);
1211	last = c;
1212	lost++;
1213	}
1214	if (ORPHAN_CUTOFF < lost) {
1215	int more = lost - ORPHAN_CUTOFF;
1216	if (more == 1)
1217	describe_one_orphan(&sb, last);
1218	else
1219	strbuf_addf(&sb, _(" ... and %d more.\n"), more);
1220	}
1221
1222	fprintf(stderr,
1223	Q_(
1224	/* The singular version */
1225	"Warning: you are leaving %d commit behind, "
1226	"not connected to\n"
1227	"any of your branches:\n\n"
1228	"%s\n",
1229	/* The plural version */
1230	"Warning: you are leaving %d commits behind, "
1231	"not connected to\n"
1232	"any of your branches:\n\n"
1233	"%s\n",
1234	/* Give ngettext() the count */
1235	lost),
1236	lost,
1237	sb.buf);
1238	strbuf_release(&sb);
1239
1240	if (advice_enabled(ADVICE_DETACHED_HEAD))
1241	fprintf(stderr,
1242	Q_(
1243	/* The singular version */
1244	"If you want to keep it by creating a new branch, "
1245	"this may be a good time\nto do so with:\n\n"
1246	" git branch <new-branch-name> %s\n\n",
1247	/* The plural version */
1248	"If you want to keep them by creating a new branch, "
1249	"this may be a good time\nto do so with:\n\n"
1250	" git branch <new-branch-name> %s\n\n",
1251	/* Give ngettext() the count */
1252	lost),
1253	repo_find_unique_abbrev(the_repository, &commit->object.oid, DEFAULT_ABBREV));
1254	}
1255
1256	/*
1257	* We are about to leave commit that was at the tip of a detached
1258	* HEAD. If it is not reachable from any ref, this is the last chance
1259	* for the user to do so without resorting to reflog.
1260	*/
1261	static void orphaned_commit_warning(struct commit old_commit, struct commit new_commit)
1262	{
1263	struct rev_info revs;
1264	struct object *object = &old_commit->object;
1265
1266	repo_init_revisions(the_repository, &revs, NULL);
1267	setup_revisions(0, NULL, &revs, NULL);
1268
1269	object->flags &= ~UNINTERESTING;
1270	add_pending_object(&revs, object, oid_to_hex(&object->oid));
1271
1272	refs_for_each_ref(get_main_ref_store(the_repository),
1273	add_pending_uninteresting_ref, &revs);
1274	if (new_commit)
1275	add_pending_oid(&revs, "HEAD",
1276	&new_commit->object.oid,
1277	UNINTERESTING);
1278
1279	if (prepare_revision_walk(&revs))
1280	die(_("internal error in revision walk"));
1281	if (!(old_commit->object.flags & UNINTERESTING))
1282	suggest_reattach(old_commit, &revs);
1283	else
1284	describe_detached_head(_("Previous HEAD position was"), old_commit);
1285
1286	/* Clean up objects used, as they will be reused. */
1287	repo_clear_commit_marks(the_repository, ALL_REV_FLAGS);
1288	release_revisions(&revs);
1289	}
1290
1291	static int switch_branches(const struct checkout_opts *opts,
1292	struct branch_info *new_branch_info)
1293	{
1294	int ret = 0;
1295	struct branch_info old_branch_info = { 0 };
1296	struct object_id rev;
1297	int flag, writeout_error = 0;
1298	int do_merge = 1;
1299	int created_autostash = 0;
1300	bool autostash_conflicted = false;
1301	struct strbuf old_commit_shortname = STRBUF_INIT;
1302	struct strbuf autostash_msg = STRBUF_INIT;
1303	const char *stash_label_base = NULL;
1304
1305	trace2_cmd_mode("branch");
1306
1307	memset(&old_branch_info, 0, sizeof(old_branch_info));
1308	old_branch_info.path = refs_resolve_refdup(get_main_ref_store(the_repository),
1309	"HEAD", 0, &rev, &flag);
1310	if (old_branch_info.path)
1311	old_branch_info.commit = lookup_commit_reference_gently(the_repository, &rev, 1);
1312	if (!(flag & REF_ISSYMREF))
1313	FREE_AND_NULL(old_branch_info.path);
1314
1315	if (old_branch_info.path) {
1316	const char *const prefix = "refs/heads/";
1317	const char *p;
1318	if (skip_prefix(old_branch_info.path, prefix, &p))
1319	old_branch_info.name = xstrdup(p);
1320	}
1321
1322	if (opts->new_orphan_branch && opts->orphan_from_empty_tree) {
1323	if (new_branch_info->name)
1324	BUG("'switch --orphan' should never accept a commit as starting point");
1325	new_branch_info->commit = NULL;
1326	new_branch_info->name = xstrdup("(empty)");
1327	do_merge = 1;
1328	}
1329
1330	if (!new_branch_info->name) {
1331	new_branch_info->name = xstrdup("HEAD");
1332	new_branch_info->commit = old_branch_info.commit;
1333	if (!new_branch_info->commit)
1334	die(_("You are on a branch yet to be born"));
1335	parse_commit_or_die(new_branch_info->commit);
1336
1337	if (opts->only_merge_on_switching_branches)
1338	do_merge = 0;
1339	}
1340
1341	if (old_branch_info.name) {
1342	stash_label_base = old_branch_info.name;
1343	} else if (old_branch_info.commit) {
1344	strbuf_add_unique_abbrev(&old_commit_shortname,
1345	&old_branch_info.commit->object.oid,
1346	DEFAULT_ABBREV);
1347	stash_label_base = old_commit_shortname.buf;
1348	}
1349
1350	if (do_merge) {
1351	ret = merge_working_tree(opts, &old_branch_info, new_branch_info,
1352	opts->merge, &writeout_error);
1353	if (ret == MERGE_WORKING_TREE_UNPACK_FAILED && opts->merge) {
1354	strbuf_addf(&autostash_msg,
1355	"autostash while switching to '%s'",
1356	new_branch_info->name);
1357	create_autostash_ref(the_repository,
1358	"CHECKOUT_AUTOSTASH_HEAD",
1359	autostash_msg.buf, true);
1360	created_autostash = 1;
1361	ret = merge_working_tree(opts, &old_branch_info, new_branch_info,
1362	false, &writeout_error);
1363	}
1364	if (created_autostash) {
1365	if (opts->conflict_style >= 0) {
1366	struct strbuf cfg = STRBUF_INIT;
1367	strbuf_addf(&cfg, "merge.conflictStyle=%s",
1368	conflict_style_name(opts->conflict_style));
1369	git_config_push_parameter(cfg.buf);
1370	strbuf_release(&cfg);
1371	}
1372	apply_autostash_ref(the_repository,
1373	"CHECKOUT_AUTOSTASH_HEAD",
1374	new_branch_info->name,
1375	"local",
1376	stash_label_base,
1377	autostash_msg.buf,
1378	&autostash_conflicted);
1379	}
1380	if (ret) {
1381	branch_info_release(&old_branch_info);
1382	strbuf_release(&old_commit_shortname);
1383	strbuf_release(&autostash_msg);
1384	return ret < 0 ? 1 : ret;
1385	}
1386	}
1387
1388	if (!opts->quiet && !old_branch_info.path && old_branch_info.commit && new_branch_info->commit != old_branch_info.commit)
1389	orphaned_commit_warning(old_branch_info.commit, new_branch_info->commit);
1390
1391	if (autostash_conflicted && !opts->quiet)
1392	fputc('\n', stderr);
1393	update_refs_for_switch(opts, &old_branch_info, new_branch_info);
1394
1395	if (created_autostash) {
1396	discard_index(the_repository->index);
1397	if (repo_read_index(the_repository) < 0)
1398	die(_("index file corrupt"));
1399
1400	if (!opts->quiet && new_branch_info->commit) {
1401	printf(_("The following paths have local changes:\n"));
1402	show_local_changes(&new_branch_info->commit->object,
1403	&opts->diff_options);
1404	}
1405	}
1406
1407	ret = post_checkout_hook(old_branch_info.commit, new_branch_info->commit, 1);
1408	branch_info_release(&old_branch_info);
1409	strbuf_release(&old_commit_shortname);
1410	strbuf_release(&autostash_msg);
1411
1412	return ret \|\| writeout_error;
1413	}
1414
1415	static int git_checkout_config(const char var, const char value,
1416	const struct config_context ctx, void cb)
1417	{
1418	struct checkout_opts *opts = cb;
1419
1420	if (!strcmp(var, "diff.ignoresubmodules")) {
1421	if (!value)
1422	return config_error_nonbool(var);
1423	handle_ignore_submodules_arg(&opts->diff_options, value);
1424	return 0;
1425	}
1426	if (!strcmp(var, "checkout.guess")) {
1427	opts->dwim_new_local_branch = git_config_bool(var, value);
1428	return 0;
1429	}
1430
1431	if (starts_with(var, "submodule."))
1432	return git_default_submodule_config(var, value, NULL);
1433
1434	return git_xmerge_config(var, value, ctx, NULL);
1435	}
1436
1437	static void setup_new_branch_info_and_source_tree(
1438	struct branch_info *new_branch_info,
1439	struct checkout_opts *opts,
1440	struct object_id *rev,
1441	const char *arg)
1442	{
1443	struct tree **source_tree = &opts->source_tree;
1444	struct object_id branch_rev;
1445
1446	/* treat '@' as a shortcut for 'HEAD' */
1447	new_branch_info->name = !strcmp(arg, "@") ? xstrdup("HEAD") :
1448	xstrdup(arg);
1449	setup_branch_path(new_branch_info);
1450
1451	if (!check_refname_format(new_branch_info->path, 0) &&
1452	!refs_read_ref(get_main_ref_store(the_repository), new_branch_info->path, &branch_rev))
1453	oidcpy(rev, &branch_rev);
1454	else
1455	/* not an existing branch */
1456	FREE_AND_NULL(new_branch_info->path);
1457
1458	new_branch_info->commit = lookup_commit_reference_gently(the_repository, rev, 1);
1459	if (!new_branch_info->commit) {
1460	/* not a commit */
1461	*source_tree = repo_parse_tree_indirect(the_repository, rev);
1462	if (!*source_tree)
1463	die(_("unable to read tree (%s)"), oid_to_hex(rev));
1464	} else {
1465	parse_commit_or_die(new_branch_info->commit);
1466	*source_tree = repo_get_commit_tree(the_repository,
1467	new_branch_info->commit);
1468	if (!*source_tree)
1469	die(_("unable to read tree (%s)"),
1470	oid_to_hex(&new_branch_info->commit->object.oid));
1471	}
1472	}
1473
1474
1475	enum checkout_command {
1476	CHECKOUT_CHECKOUT = 1,
1477	CHECKOUT_SWITCH = 2,
1478	CHECKOUT_RESTORE = 3,
1479	};
1480
1481	static char parse_remote_branch(const char arg,
1482	struct object_id *rev,
1483	int could_be_checkout_paths,
1484	enum checkout_command which_command)
1485	{
1486	int num_matches = 0;
1487	char *remote = unique_tracking_name(arg, rev, &num_matches);
1488
1489	if (remote && could_be_checkout_paths) {
1490	die(_("'%s' could be both a local file and a tracking branch.\n"
1491	"Please use -- (and optionally --no-guess) to disambiguate"),
1492	arg);
1493	}
1494
1495	if (!remote && num_matches > 1) {
1496	if (advice_enabled(ADVICE_CHECKOUT_AMBIGUOUS_REMOTE_BRANCH_NAME)) {
1497	const char *cmdname;
1498
1499	switch (which_command) {
1500	case CHECKOUT_CHECKOUT:
1501	cmdname = "checkout";
1502	break;
1503	case CHECKOUT_SWITCH:
1504	cmdname = "switch";
1505	break;
1506	default:
1507	BUG("command <%d> should not reach parse_remote_branch",
1508	which_command);
1509	break;
1510	}
1511
1512	advise(_("If you meant to check out a remote tracking branch on, e.g. 'origin',\n"
1513	"you can do so by fully qualifying the name with the --track option:\n"
1514	"\n"
1515	" git %s --track origin/<name>\n"
1516	"\n"
1517	"If you'd like to always have checkouts of an ambiguous <name> prefer\n"
1518	"one remote, e.g. the 'origin' remote, consider setting\n"
1519	"checkout.defaultRemote=origin in your config."),
1520	cmdname);
1521	}
1522
1523	die(_("'%s' matched multiple (%d) remote tracking branches"),
1524	arg, num_matches);
1525	}
1526
1527	return remote;
1528	}
1529
1530	static int parse_branchname_arg(int argc, const char **argv,
1531	int dwim_new_local_branch_ok,
1532	enum checkout_command which_command,
1533	struct branch_info *new_branch_info,
1534	struct checkout_opts *opts,
1535	struct object_id *rev)
1536	{
1537	const char **new_branch = &opts->new_branch;
1538	int argcount = 0;
1539	const char *arg;
1540	char *remote = NULL;
1541	int dash_dash_pos;
1542	int has_dash_dash = 0;
1543	int i;
1544
1545	/*
1546	* case 1: git checkout <ref> -- [<paths>]
1547	*
1548	* <ref> must be a valid tree, everything after the '--' must be
1549	* a path.
1550	*
1551	* case 2: git checkout -- [<paths>]
1552	*
1553	* everything after the '--' must be paths.
1554	*
1555	* case 3: git checkout <something> [--]
1556	*
1557	* (a) If <something> is a commit, that is to
1558	* switch to the branch or detach HEAD at it. As a special case,
1559	* if <something> is A...B (missing A or B means HEAD but you can
1560	* omit at most one side), and if there is a unique merge base
1561	* between A and B, A...B names that merge base.
1562	*
1563	* (b) If <something> is _not_ a commit, either "--" is present
1564	* or <something> is not a path, no -t or -b was given,
1565	* and there is a tracking branch whose name is <something>
1566	* in one and only one remote (or if the branch exists on the
1567	* remote named in checkout.defaultRemote), then this is a
1568	* short-hand to fork local <something> from that
1569	* remote-tracking branch.
1570	*
1571	* (c) Otherwise, if "--" is present, treat it like case (1).
1572	*
1573	* (d) Otherwise :
1574	* - if it's a reference, treat it like case (1)
1575	* - else if it's a path, treat it like case (2)
1576	* - else: fail.
1577	*
1578	* case 4: git checkout <something> <paths>
1579	*
1580	* The first argument must not be ambiguous.
1581	* - If it's only a reference, treat it like case (1).
1582	* - If it's only a path, treat it like case (2).
1583	* - else: fail.
1584	*
1585	*/
1586	if (!argc)
1587	return 0;
1588
1589	if (!opts->accept_pathspec) {
1590	if (argc > 1)
1591	die(_("only one reference expected"));
1592	has_dash_dash = 1; /* helps disambiguate */
1593	}
1594
1595	arg = argv[0];
1596	dash_dash_pos = -1;
1597	for (i = 0; i < argc; i++) {
1598	if (opts->accept_pathspec && !strcmp(argv[i], "--")) {
1599	dash_dash_pos = i;
1600	break;
1601	}
1602	}
1603	if (dash_dash_pos == 0)
1604	return 1; /* case (2) */
1605	else if (dash_dash_pos == 1)
1606	has_dash_dash = 1; /* case (3) or (1) */
1607	else if (dash_dash_pos >= 2)
1608	die(_("only one reference expected, %d given."), dash_dash_pos);
1609	opts->count_checkout_paths = !opts->quiet && !has_dash_dash;
1610
1611	if (!strcmp(arg, "-"))
1612	arg = "@{-1}";
1613
1614	if (repo_get_oid_mb(the_repository, arg, rev)) {
1615	/*
1616	* Either case (3) or (4), with <something> not being
1617	* a commit, or an attempt to use case (1) with an
1618	* invalid ref.
1619	*
1620	* It's likely an error, but we need to find out if
1621	* we should auto-create the branch, case (3).(b).
1622	*/
1623	int recover_with_dwim = dwim_new_local_branch_ok;
1624
1625	int could_be_checkout_paths = !has_dash_dash &&
1626	check_filename(opts->prefix, arg);
1627
1628	if (!has_dash_dash && !no_wildcard(arg))
1629	recover_with_dwim = 0;
1630
1631	/*
1632	* Accept "git checkout foo", "git checkout foo --"
1633	* and "git switch foo" as candidates for dwim.
1634	*/
1635	if (!(argc == 1 && !has_dash_dash) &&
1636	!(argc == 2 && has_dash_dash) &&
1637	opts->accept_pathspec)
1638	recover_with_dwim = 0;
1639
1640	if (recover_with_dwim) {
1641	remote = parse_remote_branch(arg, rev,
1642	could_be_checkout_paths,
1643	which_command);
1644	if (remote) {
1645	*new_branch = arg;
1646	arg = remote;
1647	/* DWIMmed to create local branch, case (3).(b) */
1648	} else {
1649	recover_with_dwim = 0;
1650	}
1651	}
1652
1653	if (!recover_with_dwim) {
1654	if (has_dash_dash)
1655	die(_("invalid reference: %s"), arg);
1656	return argcount;
1657	}
1658	}
1659
1660	/* we can't end up being in (2) anymore, eat the argument */
1661	argcount++;
1662	argv++;
1663	argc--;
1664
1665	setup_new_branch_info_and_source_tree(new_branch_info, opts, rev, arg);
1666
1667	if (!opts->source_tree) /* case (1): want a tree */
1668	die(_("reference is not a tree: %s"), arg);
1669
1670	if (!has_dash_dash) { /* case (3).(d) -> (1) */
1671	/*
1672	* Do not complain the most common case
1673	* git checkout branch
1674	* even if there happen to be a file called 'branch';
1675	* it would be extremely annoying.
1676	*/
1677	if (argc)
1678	verify_non_filename(the_repository, opts->prefix, arg);
1679	} else if (opts->accept_pathspec) {
1680	argcount++;
1681	argv++;
1682	argc--;
1683	}
1684
1685	free(remote);
1686	return argcount;
1687	}
1688
1689	static int switch_unborn_to_new_branch(const struct checkout_opts *opts)
1690	{
1691	int status;
1692	struct strbuf branch_ref = STRBUF_INIT;
1693
1694	trace2_cmd_mode("unborn");
1695
1696	if (!opts->new_branch)
1697	die(_("You are on a branch yet to be born"));
1698	strbuf_addf(&branch_ref, "refs/heads/%s", opts->new_branch);
1699	status = refs_update_symref(get_main_ref_store(the_repository),
1700	"HEAD", branch_ref.buf, "checkout -b");
1701	strbuf_release(&branch_ref);
1702	if (!opts->quiet)
1703	fprintf(stderr, _("Switched to a new branch '%s'\n"),
1704	opts->new_branch);
1705	return status;
1706	}
1707
1708	static void die_expecting_a_branch(const struct branch_info *branch_info)
1709	{
1710	struct object_id oid;
1711	char *to_free;
1712	int code;
1713
1714	if (repo_dwim_ref(the_repository, branch_info->name,
1715	strlen(branch_info->name), &oid, &to_free, 0) == 1) {
1716	const char *ref = to_free;
1717
1718	if (skip_prefix(ref, "refs/tags/", &ref))
1719	code = die_message(_("a branch is expected, got tag '%s'"), ref);
1720	else if (skip_prefix(ref, "refs/remotes/", &ref))
1721	code = die_message(_("a branch is expected, got remote branch '%s'"), ref);
1722	else
1723	code = die_message(_("a branch is expected, got '%s'"), ref);
1724	}
1725	else if (branch_info->commit)
1726	code = die_message(_("a branch is expected, got commit '%s'"), branch_info->name);
1727	else
1728	/*
1729	* This case should never happen because we already die() on
1730	* non-commit, but just in case.
1731	*/
1732	code = die_message(_("a branch is expected, got '%s'"), branch_info->name);
1733
1734	if (advice_enabled(ADVICE_SUGGEST_DETACHING_HEAD))
1735	advise(_("If you want to detach HEAD at the commit, try again with the --detach option."));
1736
1737	exit(code);
1738	}
1739
1740	static void die_if_some_operation_in_progress(void)
1741	{
1742	struct wt_status_state state;
1743
1744	memset(&state, 0, sizeof(state));
1745	wt_status_get_state(the_repository, &state, 0);
1746
1747	if (state.merge_in_progress)
1748	die(_("cannot switch branch while merging\n"
1749	"Consider \"git merge --quit\" "
1750	"or \"git worktree add\"."));
1751	if (state.am_in_progress)
1752	die(_("cannot switch branch in the middle of an am session\n"
1753	"Consider \"git am --quit\" "
1754	"or \"git worktree add\"."));
1755	if (state.rebase_interactive_in_progress \|\| state.rebase_in_progress)
1756	die(_("cannot switch branch while rebasing\n"
1757	"Consider \"git rebase --quit\" "
1758	"or \"git worktree add\"."));
1759	if (state.cherry_pick_in_progress)
1760	die(_("cannot switch branch while cherry-picking\n"
1761	"Consider \"git cherry-pick --quit\" "
1762	"or \"git worktree add\"."));
1763	if (state.revert_in_progress)
1764	die(_("cannot switch branch while reverting\n"
1765	"Consider \"git revert --quit\" "
1766	"or \"git worktree add\"."));
1767	if (state.bisect_in_progress)
1768	warning(_("you are switching branch while bisecting"));
1769
1770	wt_status_state_free_buffers(&state);
1771	}
1772
1773	/*
1774	* die if attempting to checkout an existing branch that is in use
1775	* in another worktree, unless ignore-other-wortrees option is given.
1776	* The check is bypassed when the branch is already the current one,
1777	* as it will not make things any worse.
1778	*/
1779	static void die_if_switching_to_a_branch_in_use(struct checkout_opts *opts,
1780	const char *full_ref)
1781	{
1782	int flags;
1783	char *head_ref;
1784
1785	if (opts->ignore_other_worktrees)
1786	return;
1787	head_ref = refs_resolve_refdup(get_main_ref_store(the_repository),
1788	"HEAD", 0, NULL, &flags);
1789	if (head_ref && (!(flags & REF_ISSYMREF) \|\| strcmp(head_ref, full_ref)))
1790	die_if_checked_out(full_ref, 1);
1791	free(head_ref);
1792	}
1793
1794	static int checkout_branch(struct checkout_opts *opts,
1795	struct branch_info *new_branch_info)
1796	{
1797	struct repo_config_values *cfg = repo_config_values(the_repository);
1798	int noop_switch = (!new_branch_info->name &&
1799	!opts->new_branch &&
1800	!opts->force_detach);
1801
1802	if (opts->pathspec.nr)
1803	die(_("paths cannot be used with switching branches"));
1804
1805	if (opts->patch_mode)
1806	die(_("'%s' cannot be used with switching branches"),
1807	"--patch");
1808
1809	if (opts->overlay_mode != -1)
1810	die(_("'%s' cannot be used with switching branches"),
1811	"--[no]-overlay");
1812
1813	if (opts->writeout_stage) {
1814	const char *msg;
1815	if (noop_switch)
1816	msg = _("'%s' needs the paths to check out");
1817	else
1818	msg = _("'%s' cannot be used with switching branches");
1819	die(msg, "--ours/--theirs");
1820	}
1821
1822	if (opts->force && opts->merge)
1823	die(_("'%s' cannot be used with '%s'"), "-f", "-m");
1824
1825	if (opts->discard_changes && opts->merge)
1826	die(_("'%s' cannot be used with '%s'"), "--discard-changes", "--merge");
1827
1828	if (opts->force_detach && opts->new_branch)
1829	die(_("'%s' cannot be used with '%s'"),
1830	"--detach", "-b/-B/--orphan");
1831
1832	if (opts->new_orphan_branch) {
1833	if (opts->track != BRANCH_TRACK_UNSPECIFIED)
1834	die(_("'%s' cannot be used with '%s'"), "--orphan", "-t");
1835	if (opts->orphan_from_empty_tree && new_branch_info->name)
1836	die(_("'%s' cannot take <start-point>"), "--orphan");
1837	} else if (opts->force_detach) {
1838	if (opts->track != BRANCH_TRACK_UNSPECIFIED)
1839	die(_("'%s' cannot be used with '%s'"), "--detach", "-t");
1840	} else if (opts->track == BRANCH_TRACK_UNSPECIFIED)
1841	opts->track = cfg->branch_track;
1842
1843	if (new_branch_info->name && !new_branch_info->commit)
1844	die(_("Cannot switch branch to a non-commit '%s'"),
1845	new_branch_info->name);
1846
1847	if (noop_switch &&
1848	!opts->switch_branch_doing_nothing_is_ok)
1849	die(_("missing branch or commit argument"));
1850
1851	if (!opts->implicit_detach &&
1852	!opts->force_detach &&
1853	!opts->new_branch &&
1854	!opts->new_branch_force &&
1855	new_branch_info->name &&
1856	!new_branch_info->path)
1857	die_expecting_a_branch(new_branch_info);
1858
1859	if (!opts->can_switch_when_in_progress)
1860	die_if_some_operation_in_progress();
1861
1862	/* "git checkout <branch>" */
1863	if (new_branch_info->path && !opts->force_detach && !opts->new_branch)
1864	die_if_switching_to_a_branch_in_use(opts, new_branch_info->path);
1865
1866	/* "git checkout -B <branch>" */
1867	if (opts->new_branch_force) {
1868	char *full_ref = xstrfmt("refs/heads/%s", opts->new_branch);
1869	die_if_switching_to_a_branch_in_use(opts, full_ref);
1870	free(full_ref);
1871	}
1872
1873	if (!new_branch_info->commit && opts->new_branch) {
1874	struct object_id rev;
1875	int flag;
1876
1877	if (!refs_read_ref_full(get_main_ref_store(the_repository), "HEAD", 0, &rev, &flag) &&
1878	(flag & REF_ISSYMREF) && is_null_oid(&rev))
1879	return switch_unborn_to_new_branch(opts);
1880	}
1881	return switch_branches(opts, new_branch_info);
1882	}
1883
1884	static int parse_opt_conflict(const struct option o, const char arg, int unset)
1885	{
1886	struct checkout_opts *opts = o->value;
1887
1888	if (unset) {
1889	opts->conflict_style = -1;
1890	return 0;
1891	}
1892	opts->conflict_style = parse_conflict_style_name(arg);
1893	if (opts->conflict_style < 0)
1894	return error(_("unknown conflict style '%s'"), arg);
1895	/* --conflict overrides a previous --no-merge */
1896	if (!opts->merge)
1897	opts->merge = -1;
1898
1899	return 0;
1900	}
1901
1902	static struct option add_common_options(struct checkout_opts opts,
1903	struct option *prevopts)
1904	{
1905	struct option options[] = {
1906	OPT__QUIET(&opts->quiet, N_("suppress progress reporting")),
1907	OPT_CALLBACK_F(0, "recurse-submodules", NULL,
1908	"checkout", "control recursive updating of submodules",
1909	PARSE_OPT_OPTARG, option_parse_recurse_submodules_worktree_updater),
1910	OPT_BOOL(0, "progress", &opts->show_progress, N_("force progress reporting")),
1911	OPT_BOOL('m', "merge", &opts->merge, N_("perform a 3-way merge with the new branch")),
1912	OPT_CALLBACK(0, "conflict", opts, N_("style"),
1913	N_("conflict style (merge, diff3, or zdiff3)"),
1914	parse_opt_conflict),
1915	OPT_END()
1916	};
1917	struct option *newopts = parse_options_concat(prevopts, options);
1918	free(prevopts);
1919	return newopts;
1920	}
1921
1922	static struct option *add_common_switch_branch_options(
1923	struct checkout_opts opts, struct option prevopts)
1924	{
1925	struct option options[] = {
1926	OPT_BOOL('d', "detach", &opts->force_detach, N_("detach HEAD at named commit")),
1927	OPT_CALLBACK_F('t', "track", opts, "(direct\|inherit\|fetch)[,...]",
1928	N_("set branch tracking configuration"),
1929	PARSE_OPT_OPTARG,
1930	parse_opt_checkout_track),
1931	OPT__FORCE(&opts->force, N_("force checkout (throw away local modifications)"),
1932	PARSE_OPT_NOCOMPLETE),
1933	OPT_STRING(0, "orphan", &opts->new_orphan_branch, N_("new-branch"), N_("new unborn branch")),
1934	OPT_BOOL_F(0, "overwrite-ignore", &opts->overwrite_ignore,
1935	N_("update ignored files (default)"),
1936	PARSE_OPT_NOCOMPLETE),
1937	OPT_BOOL(0, "ignore-other-worktrees", &opts->ignore_other_worktrees,
1938	N_("do not check if another worktree is using this branch")),
1939	OPT_END()
1940	};
1941	struct option *newopts = parse_options_concat(prevopts, options);
1942	free(prevopts);
1943	return newopts;
1944	}
1945
1946	static struct option add_checkout_path_options(struct checkout_opts opts,
1947	struct option *prevopts)
1948	{
1949	struct option options[] = {
1950	OPT_SET_INT_F('2', "ours", &opts->writeout_stage,
1951	N_("checkout our version for unmerged files"),
1952	2, PARSE_OPT_NONEG),
1953	OPT_SET_INT_F('3', "theirs", &opts->writeout_stage,
1954	N_("checkout their version for unmerged files"),
1955	3, PARSE_OPT_NONEG),
1956	OPT_BOOL('p', "patch", &opts->patch_mode, N_("select hunks interactively")),
1957	OPT_DIFF_UNIFIED(&opts->patch_context),
1958	OPT_DIFF_INTERHUNK_CONTEXT(&opts->patch_interhunk_context),
1959	OPT_BOOL(0, "ignore-skip-worktree-bits", &opts->ignore_skipworktree,
1960	N_("do not limit pathspecs to sparse entries only")),
1961	OPT_PATHSPEC_FROM_FILE(&opts->pathspec_from_file),
1962	OPT_PATHSPEC_FILE_NUL(&opts->pathspec_file_nul),
1963	OPT_END()
1964	};
1965	struct option *newopts = parse_options_concat(prevopts, options);
1966	free(prevopts);
1967	return newopts;
1968	}
1969
1970	/* create-branch option (either b or c) */
1971	static char cb_option = 'b';
1972
1973	static int checkout_main(int argc, const char *argv, const char prefix,
1974	struct checkout_opts opts, struct option options,
1975	enum checkout_command which_command)
1976	{
1977	int parseopt_flags = 0;
1978	struct branch_info new_branch_info = { 0 };
1979	int ret;
1980
1981	static const char * const checkout_usage[] = {
1982	N_("git checkout [<options>] <branch>"),
1983	N_("git checkout [<options>] [<branch>] -- <file>..."),
1984	NULL,
1985	};
1986
1987	static const char * const switch_branch_usage[] = {
1988	N_("git switch [<options>] [<branch>]"),
1989	NULL,
1990	};
1991
1992	static const char * const restore_usage[] = {
1993	N_("git restore [<options>] [--source=<branch>] <file>..."),
1994	NULL,
1995	};
1996
1997	const char * const *usagestr;
1998
1999	switch (which_command) {
2000	case CHECKOUT_CHECKOUT:
2001	usagestr = checkout_usage;
2002	break;
2003	case CHECKOUT_SWITCH:
2004	usagestr = switch_branch_usage;
2005	break;
2006	case CHECKOUT_RESTORE:
2007	usagestr = restore_usage;
2008	break;
2009	default:
2010	BUG("no such checkout variant %d", which_command);
2011	}
2012
2013	opts->overwrite_ignore = 1;
2014	opts->prefix = prefix;
2015	opts->show_progress = -1;
2016
2017	repo_config(the_repository, git_checkout_config, opts);
2018	if (the_repository->gitdir) {
2019	prepare_repo_settings(the_repository);
2020	the_repository->settings.command_requires_full_index = 0;
2021	}
2022
2023	opts->track = BRANCH_TRACK_UNSPECIFIED;
2024
2025	if (!opts->accept_pathspec && !opts->accept_ref)
2026	BUG("make up your mind, you need to take _something_");
2027	if (opts->accept_pathspec && opts->accept_ref)
2028	parseopt_flags = PARSE_OPT_KEEP_DASHDASH;
2029
2030	argc = parse_options(argc, argv, prefix, options,
2031	usagestr, parseopt_flags);
2032
2033	if (opts->patch_context < -1)
2034	die(_("'%s' cannot be negative"), "--unified");
2035	if (opts->patch_interhunk_context < -1)
2036	die(_("'%s' cannot be negative"), "--inter-hunk-context");
2037
2038	if (!opts->patch_mode) {
2039	if (opts->patch_context != -1)
2040	die(_("the option '%s' requires '%s'"), "--unified", "--patch");
2041	if (opts->patch_interhunk_context != -1)
2042	die(_("the option '%s' requires '%s'"), "--inter-hunk-context", "--patch");
2043	if (!opts->auto_advance)
2044	die(_("the option '%s' requires '%s'"), "--no-auto-advance", "--patch");
2045	}
2046
2047	if (opts->show_progress < 0) {
2048	if (opts->quiet)
2049	opts->show_progress = 0;
2050	else
2051	opts->show_progress = isatty(2);
2052	}
2053
2054	/* --conflicts implies --merge */
2055	if (opts->merge == -1)
2056	opts->merge = opts->conflict_style >= 0;
2057
2058	if (opts->force) {
2059	opts->discard_changes = 1;
2060	opts->ignore_unmerged_opt = "--force";
2061	opts->ignore_unmerged = 1;
2062	}
2063
2064	if ((!!opts->new_branch + !!opts->new_branch_force + !!opts->new_orphan_branch) > 1)
2065	die(_("options '-%c', '-%c', and '%s' cannot be used together"),
2066	cb_option, toupper(cb_option), "--orphan");
2067
2068	if (opts->overlay_mode == 1 && opts->patch_mode)
2069	die(_("options '%s' and '%s' cannot be used together"), "-p", "--overlay");
2070
2071	if (opts->checkout_index >= 0 \|\| opts->checkout_worktree >= 0) {
2072	if (opts->checkout_index < 0)
2073	opts->checkout_index = 0;
2074	if (opts->checkout_worktree < 0)
2075	opts->checkout_worktree = 0;
2076	} else {
2077	if (opts->checkout_index < 0)
2078	opts->checkout_index = -opts->checkout_index - 1;
2079	if (opts->checkout_worktree < 0)
2080	opts->checkout_worktree = -opts->checkout_worktree - 1;
2081	}
2082	if (opts->checkout_index < 0 \|\| opts->checkout_worktree < 0)
2083	BUG("these flags should be non-negative by now");
2084	/*
2085	* convenient shortcut: "git restore --staged [--worktree]" equals
2086	* "git restore --staged [--worktree] --source HEAD"
2087	*/
2088	if (!opts->from_treeish && opts->checkout_index)
2089	opts->from_treeish = "HEAD";
2090
2091	/*
2092	* From here on, new_branch will contain the branch to be checked out,
2093	* and new_branch_force and new_orphan_branch will tell us which one of
2094	* -b/-B/-c/-C/--orphan is being used.
2095	*/
2096	if (opts->new_branch_force)
2097	opts->new_branch = opts->new_branch_force;
2098
2099	if (opts->new_orphan_branch)
2100	opts->new_branch = opts->new_orphan_branch;
2101
2102	/* --track without -c/-C/-b/-B/--orphan should DWIM */
2103	if (opts->track != BRANCH_TRACK_UNSPECIFIED && !opts->new_branch) {
2104	const char *argv0 = argv[0];
2105	if (!argc \|\| !strcmp(argv0, "--"))
2106	die(_("--track needs a branch name"));
2107	skip_prefix(argv0, "refs/", &argv0);
2108	skip_prefix(argv0, "remotes/", &argv0);
2109	argv0 = strchr(argv0, '/');
2110	if (!argv0 \|\| !argv0[1])
2111	die(_("missing branch name; try -%c"), cb_option);
2112	opts->new_branch = argv0 + 1;
2113	}
2114
2115	/*
2116	* Extract branch name from command line arguments, so
2117	* all that is left is pathspecs.
2118	*
2119	* Handle
2120	*
2121	* 1) git checkout <tree> -- [<paths>]
2122	* 2) git checkout -- [<paths>]
2123	* 3) git checkout <something> [<paths>]
2124	*
2125	* including "last branch" syntax and DWIM-ery for names of
2126	* remote branches, erroring out for invalid or ambiguous cases.
2127	*/
2128	if (argc && opts->accept_ref) {
2129	struct object_id rev;
2130	int dwim_ok =
2131	!opts->patch_mode &&
2132	opts->dwim_new_local_branch &&
2133	opts->track == BRANCH_TRACK_UNSPECIFIED &&
2134	!opts->new_branch;
2135	int n;
2136
2137	if (opts->fetch)
2138	fetch_remote_for_start_point(argv[0], opts->quiet);
2139
2140	n = parse_branchname_arg(argc, argv, dwim_ok, which_command,
2141	&new_branch_info, opts, &rev);
2142	argv += n;
2143	argc -= n;
2144	} else if (!opts->accept_ref && opts->from_treeish) {
2145	struct object_id rev;
2146
2147	if (repo_get_oid_mb(the_repository, opts->from_treeish, &rev))
2148	die(_("could not resolve '%s'"), opts->from_treeish);
2149
2150	setup_new_branch_info_and_source_tree(&new_branch_info,
2151	opts, &rev,
2152	opts->from_treeish);
2153
2154	if (!opts->source_tree)
2155	die(_("reference is not a tree: %s"), opts->from_treeish);
2156	}
2157
2158	if (argc) {
2159	parse_pathspec(&opts->pathspec, 0,
2160	opts->patch_mode ? PATHSPEC_PREFIX_ORIGIN : 0,
2161	prefix, argv);
2162
2163	if (!opts->pathspec.nr)
2164	die(_("invalid path specification"));
2165
2166	/*
2167	* Try to give more helpful suggestion.
2168	* new_branch && argc > 1 will be caught later.
2169	*/
2170	if (opts->new_branch && argc == 1 && !new_branch_info.commit)
2171	die(_("'%s' is not a commit and a branch '%s' cannot be created from it"),
2172	argv[0], opts->new_branch);
2173
2174	if (opts->force_detach)
2175	die(_("git checkout: --detach does not take a path argument '%s'"),
2176	argv[0]);
2177	}
2178
2179	if (opts->pathspec_from_file) {
2180	if (opts->pathspec.nr)
2181	die(_("'%s' and pathspec arguments cannot be used together"), "--pathspec-from-file");
2182
2183	if (opts->force_detach)
2184	die(_("options '%s' and '%s' cannot be used together"), "--pathspec-from-file", "--detach");
2185
2186	if (opts->patch_mode)
2187	die(_("options '%s' and '%s' cannot be used together"), "--pathspec-from-file", "--patch");
2188
2189	parse_pathspec_file(&opts->pathspec, 0,
2190	0,
2191	prefix, opts->pathspec_from_file, opts->pathspec_file_nul);
2192	} else if (opts->pathspec_file_nul) {
2193	die(_("the option '%s' requires '%s'"), "--pathspec-file-nul", "--pathspec-from-file");
2194	}
2195
2196	opts->pathspec.recursive = 1;
2197
2198	if (opts->pathspec.nr) {
2199	if (1 < !!opts->writeout_stage + !!opts->force + !!opts->merge)
2200	die(_("git checkout: --ours/--theirs, --force and --merge are incompatible when\n"
2201	"checking out of the index."));
2202	} else {
2203	if (opts->accept_pathspec && !opts->empty_pathspec_ok &&
2204	!opts->patch_mode) /* patch mode is special */
2205	die(_("you must specify path(s) to restore"));
2206	}
2207
2208	if (opts->new_branch) {
2209	struct strbuf buf = STRBUF_INIT;
2210
2211	if (opts->new_branch_force)
2212	opts->branch_exists = validate_branchname(opts->new_branch, &buf);
2213	else
2214	opts->branch_exists =
2215	validate_new_branchname(opts->new_branch, &buf, 0);
2216	strbuf_release(&buf);
2217	}
2218
2219	if (opts->patch_mode \|\| opts->pathspec.nr)
2220	ret = checkout_paths(opts, &new_branch_info);
2221	else
2222	ret = checkout_branch(opts, &new_branch_info);
2223
2224	branch_info_release(&new_branch_info);
2225	clear_pathspec(&opts->pathspec);
2226	free(opts->pathspec_from_file);
2227	free(options);
2228
2229	return ret;
2230	}
2231
2232	int cmd_checkout(int argc,
2233	const char **argv,
2234	const char *prefix,
2235	struct repository *repo UNUSED)
2236	{
2237	struct checkout_opts opts = CHECKOUT_OPTS_INIT;
2238	struct option *options;
2239	struct option checkout_options[] = {
2240	OPT_STRING('b', NULL, &opts.new_branch, N_("branch"),
2241	N_("create and checkout a new branch")),
2242	OPT_STRING('B', NULL, &opts.new_branch_force, N_("branch"),
2243	N_("create/reset and checkout a branch")),
2244	OPT_BOOL('l', NULL, &opts.new_branch_log, N_("create reflog for new branch")),
2245	OPT_BOOL(0, "guess", &opts.dwim_new_local_branch,
2246	N_("second guess 'git checkout <no-such-branch>' (default)")),
2247	OPT_BOOL(0, "overlay", &opts.overlay_mode, N_("use overlay mode (default)")),
2248	OPT_BOOL(0, "auto-advance", &opts.auto_advance,
2249	N_("auto advance to the next file when selecting hunks interactively")),
2250	OPT_END()
2251	};
2252
2253	opts.dwim_new_local_branch = 1;
2254	opts.switch_branch_doing_nothing_is_ok = 1;
2255	opts.only_merge_on_switching_branches = 0;
2256	opts.accept_ref = 1;
2257	opts.accept_pathspec = 1;
2258	opts.implicit_detach = 1;
2259	opts.can_switch_when_in_progress = 1;
2260	opts.orphan_from_empty_tree = 0;
2261	opts.empty_pathspec_ok = 1;
2262	opts.overlay_mode = -1;
2263	opts.checkout_index = -2; /* default on */
2264	opts.checkout_worktree = -2; /* default on */
2265
2266	if (argc == 3 && !strcmp(argv[1], "-b")) {
2267	/*
2268	* User ran 'git checkout -b <branch>' and expects
2269	* the same behavior as 'git switch -c <branch>'.
2270	*/
2271	opts.switch_branch_doing_nothing_is_ok = 0;
2272	opts.only_merge_on_switching_branches = 1;
2273	}
2274
2275	options = parse_options_dup(checkout_options);
2276	options = add_common_options(&opts, options);
2277	options = add_common_switch_branch_options(&opts, options);
2278	options = add_checkout_path_options(&opts, options);
2279
2280	return checkout_main(argc, argv, prefix, &opts, options,
2281	CHECKOUT_CHECKOUT);
2282	}
2283
2284	int cmd_switch(int argc,
2285	const char **argv,
2286	const char *prefix,
2287	struct repository *repo UNUSED)
2288	{
2289	struct checkout_opts opts = CHECKOUT_OPTS_INIT;
2290	struct option *options = NULL;
2291	struct option switch_options[] = {
2292	OPT_STRING('c', "create", &opts.new_branch, N_("branch"),
2293	N_("create and switch to a new branch")),
2294	OPT_STRING('C', "force-create", &opts.new_branch_force, N_("branch"),
2295	N_("create/reset and switch to a branch")),
2296	OPT_BOOL(0, "guess", &opts.dwim_new_local_branch,
2297	N_("second guess 'git switch <no-such-branch>'")),
2298	OPT_BOOL(0, "discard-changes", &opts.discard_changes,
2299	N_("throw away local modifications")),
2300	OPT_END()
2301	};
2302
2303	opts.dwim_new_local_branch = 1;
2304	opts.accept_ref = 1;
2305	opts.accept_pathspec = 0;
2306	opts.switch_branch_doing_nothing_is_ok = 0;
2307	opts.only_merge_on_switching_branches = 1;
2308	opts.implicit_detach = 0;
2309	opts.can_switch_when_in_progress = 0;
2310	opts.orphan_from_empty_tree = 1;
2311	opts.overlay_mode = -1;
2312
2313	options = parse_options_dup(switch_options);
2314	options = add_common_options(&opts, options);
2315	options = add_common_switch_branch_options(&opts, options);
2316
2317	cb_option = 'c';
2318
2319	return checkout_main(argc, argv, prefix, &opts, options,
2320	CHECKOUT_SWITCH);
2321	}
2322
2323	int cmd_restore(int argc,
2324	const char **argv,
2325	const char *prefix,
2326	struct repository *repo UNUSED)
2327	{
2328	struct checkout_opts opts = CHECKOUT_OPTS_INIT;
2329	struct option *options;
2330	struct option restore_options[] = {
2331	OPT_STRING('s', "source", &opts.from_treeish, "<tree-ish>",
2332	N_("which tree-ish to checkout from")),
2333	OPT_BOOL('S', "staged", &opts.checkout_index,
2334	N_("restore the index")),
2335	OPT_BOOL('W', "worktree", &opts.checkout_worktree,
2336	N_("restore the working tree (default)")),
2337	OPT_BOOL(0, "ignore-unmerged", &opts.ignore_unmerged,
2338	N_("ignore unmerged entries")),
2339	OPT_BOOL(0, "overlay", &opts.overlay_mode, N_("use overlay mode")),
2340	OPT_END()
2341	};
2342
2343	opts.accept_ref = 0;
2344	opts.accept_pathspec = 1;
2345	opts.empty_pathspec_ok = 0;
2346	opts.overlay_mode = 0;
2347	opts.checkout_index = -1; /* default off */
2348	opts.checkout_worktree = -2; /* default on */
2349	opts.ignore_unmerged_opt = "--ignore-unmerged";
2350
2351	options = parse_options_dup(restore_options);
2352	options = add_common_options(&opts, options);
2353	options = add_checkout_path_options(&opts, options);
2354
2355	return checkout_main(argc, argv, prefix, &opts, options,
2356	CHECKOUT_RESTORE);
2357	}