t3507: introduce pristine-detach helper
[git/git.git] / builtin / revert.c
1 #include "cache.h"
2 #include "builtin.h"
3 #include "object.h"
4 #include "commit.h"
5 #include "tag.h"
6 #include "wt-status.h"
7 #include "run-command.h"
8 #include "exec_cmd.h"
9 #include "utf8.h"
10 #include "parse-options.h"
11 #include "cache-tree.h"
12 #include "diff.h"
13 #include "revision.h"
14 #include "rerere.h"
15 #include "merge-recursive.h"
16 #include "refs.h"
17
18 /*
19 * This implements the builtins revert and cherry-pick.
20 *
21 * Copyright (c) 2007 Johannes E. Schindelin
22 *
23 * Based on git-revert.sh, which is
24 *
25 * Copyright (c) 2005 Linus Torvalds
26 * Copyright (c) 2005 Junio C Hamano
27 */
28
29 static const char * const revert_usage[] = {
30 "git revert [options] <commit-ish>",
31 NULL
32 };
33
34 static const char * const cherry_pick_usage[] = {
35 "git cherry-pick [options] <commit-ish>",
36 NULL
37 };
38
39 static int edit, no_replay, no_commit, mainline, signoff, allow_ff;
40 static enum { REVERT, CHERRY_PICK } action;
41 static struct commit *commit;
42 static int commit_argc;
43 static const char **commit_argv;
44 static int allow_rerere_auto;
45
46 static const char *me;
47 static const char *strategy;
48
49 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
50
51 static char *get_encoding(const char *message);
52
53 static const char * const *revert_or_cherry_pick_usage(void)
54 {
55 return action == REVERT ? revert_usage : cherry_pick_usage;
56 }
57
58 static void parse_args(int argc, const char **argv)
59 {
60 const char * const * usage_str = revert_or_cherry_pick_usage();
61 int noop;
62 struct option options[] = {
63 OPT_BOOLEAN('n', "no-commit", &no_commit, "don't automatically commit"),
64 OPT_BOOLEAN('e', "edit", &edit, "edit the commit message"),
65 OPT_BOOLEAN('r', NULL, &noop, "no-op (backward compatibility)"),
66 OPT_BOOLEAN('s', "signoff", &signoff, "add Signed-off-by:"),
67 OPT_INTEGER('m', "mainline", &mainline, "parent number"),
68 OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
69 OPT_STRING(0, "strategy", &strategy, "strategy", "merge strategy"),
70 OPT_END(),
71 OPT_END(),
72 OPT_END(),
73 };
74
75 if (action == CHERRY_PICK) {
76 struct option cp_extra[] = {
77 OPT_BOOLEAN('x', NULL, &no_replay, "append commit name"),
78 OPT_BOOLEAN(0, "ff", &allow_ff, "allow fast-forward"),
79 OPT_END(),
80 };
81 if (parse_options_concat(options, ARRAY_SIZE(options), cp_extra))
82 die("program error");
83 }
84
85 commit_argc = parse_options(argc, argv, NULL, options, usage_str,
86 PARSE_OPT_KEEP_ARGV0 |
87 PARSE_OPT_KEEP_UNKNOWN);
88 if (commit_argc < 2)
89 usage_with_options(usage_str, options);
90
91 commit_argv = argv;
92 }
93
94 struct commit_message {
95 char *parent_label;
96 const char *label;
97 const char *subject;
98 char *reencoded_message;
99 const char *message;
100 };
101
102 static int get_message(const char *raw_message, struct commit_message *out)
103 {
104 const char *encoding;
105 const char *abbrev, *subject;
106 int abbrev_len, subject_len;
107 char *q;
108
109 if (!raw_message)
110 return -1;
111 encoding = get_encoding(raw_message);
112 if (!encoding)
113 encoding = "UTF-8";
114 if (!git_commit_encoding)
115 git_commit_encoding = "UTF-8";
116
117 out->reencoded_message = NULL;
118 out->message = raw_message;
119 if (strcmp(encoding, git_commit_encoding))
120 out->reencoded_message = reencode_string(raw_message,
121 git_commit_encoding, encoding);
122 if (out->reencoded_message)
123 out->message = out->reencoded_message;
124
125 abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
126 abbrev_len = strlen(abbrev);
127
128 subject_len = find_commit_subject(out->message, &subject);
129
130 out->parent_label = xmalloc(strlen("parent of ") + abbrev_len +
131 strlen("... ") + subject_len + 1);
132 q = out->parent_label;
133 q = mempcpy(q, "parent of ", strlen("parent of "));
134 out->label = q;
135 q = mempcpy(q, abbrev, abbrev_len);
136 q = mempcpy(q, "... ", strlen("... "));
137 out->subject = q;
138 q = mempcpy(q, subject, subject_len);
139 *q = '\0';
140 return 0;
141 }
142
143 static void free_message(struct commit_message *msg)
144 {
145 free(msg->parent_label);
146 free(msg->reencoded_message);
147 }
148
149 static char *get_encoding(const char *message)
150 {
151 const char *p = message, *eol;
152
153 if (!p)
154 die ("Could not read commit message of %s",
155 sha1_to_hex(commit->object.sha1));
156 while (*p && *p != '\n') {
157 for (eol = p + 1; *eol && *eol != '\n'; eol++)
158 ; /* do nothing */
159 if (!prefixcmp(p, "encoding ")) {
160 char *result = xmalloc(eol - 8 - p);
161 strlcpy(result, p + 9, eol - 8 - p);
162 return result;
163 }
164 p = eol;
165 if (*p == '\n')
166 p++;
167 }
168 return NULL;
169 }
170
171 static void add_message_to_msg(struct strbuf *msgbuf, const char *message)
172 {
173 const char *p = message;
174 while (*p && (*p != '\n' || p[1] != '\n'))
175 p++;
176
177 if (!*p)
178 strbuf_addstr(msgbuf, sha1_to_hex(commit->object.sha1));
179
180 p += 2;
181 strbuf_addstr(msgbuf, p);
182 }
183
184 static void set_author_ident_env(const char *message)
185 {
186 const char *p = message;
187 if (!p)
188 die ("Could not read commit message of %s",
189 sha1_to_hex(commit->object.sha1));
190 while (*p && *p != '\n') {
191 const char *eol;
192
193 for (eol = p; *eol && *eol != '\n'; eol++)
194 ; /* do nothing */
195 if (!prefixcmp(p, "author ")) {
196 char *line, *pend, *email, *timestamp;
197
198 p += 7;
199 line = xmemdupz(p, eol - p);
200 email = strchr(line, '<');
201 if (!email)
202 die ("Could not extract author email from %s",
203 sha1_to_hex(commit->object.sha1));
204 if (email == line)
205 pend = line;
206 else
207 for (pend = email; pend != line + 1 &&
208 isspace(pend[-1]); pend--);
209 ; /* do nothing */
210 *pend = '\0';
211 email++;
212 timestamp = strchr(email, '>');
213 if (!timestamp)
214 die ("Could not extract author time from %s",
215 sha1_to_hex(commit->object.sha1));
216 *timestamp = '\0';
217 for (timestamp++; *timestamp && isspace(*timestamp);
218 timestamp++)
219 ; /* do nothing */
220 setenv("GIT_AUTHOR_NAME", line, 1);
221 setenv("GIT_AUTHOR_EMAIL", email, 1);
222 setenv("GIT_AUTHOR_DATE", timestamp, 1);
223 free(line);
224 return;
225 }
226 p = eol;
227 if (*p == '\n')
228 p++;
229 }
230 die ("No author information found in %s",
231 sha1_to_hex(commit->object.sha1));
232 }
233
234 static void advise(const char *advice, ...)
235 {
236 va_list params;
237
238 va_start(params, advice);
239 vreportf("hint: ", advice, params);
240 va_end(params);
241 }
242
243 static void print_advice(void)
244 {
245 char *msg = getenv("GIT_CHERRY_PICK_HELP");
246
247 if (msg) {
248 fprintf(stderr, "%s\n", msg);
249 return;
250 }
251
252 advise("after resolving the conflicts, mark the corrected paths");
253 advise("with 'git add <paths>' or 'git rm <paths>'");
254
255 if (action == CHERRY_PICK)
256 advise("and commit the result with 'git commit -c %s'",
257 find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
258 }
259
260 static void write_message(struct strbuf *msgbuf, const char *filename)
261 {
262 static struct lock_file msg_file;
263
264 int msg_fd = hold_lock_file_for_update(&msg_file, filename,
265 LOCK_DIE_ON_ERROR);
266 if (write_in_full(msg_fd, msgbuf->buf, msgbuf->len) < 0)
267 die_errno("Could not write to %s.", filename);
268 strbuf_release(msgbuf);
269 if (commit_lock_file(&msg_file) < 0)
270 die("Error wrapping up %s", filename);
271 }
272
273 static struct tree *empty_tree(void)
274 {
275 struct tree *tree = xcalloc(1, sizeof(struct tree));
276
277 tree->object.parsed = 1;
278 tree->object.type = OBJ_TREE;
279 pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
280 return tree;
281 }
282
283 static NORETURN void die_dirty_index(const char *me)
284 {
285 if (read_cache_unmerged()) {
286 die_resolve_conflict(me);
287 } else {
288 if (advice_commit_before_merge)
289 die("Your local changes would be overwritten by %s.\n"
290 "Please, commit your changes or stash them to proceed.", me);
291 else
292 die("Your local changes would be overwritten by %s.\n", me);
293 }
294 }
295
296 static int fast_forward_to(const unsigned char *to, const unsigned char *from)
297 {
298 struct ref_lock *ref_lock;
299
300 read_cache();
301 if (checkout_fast_forward(from, to))
302 exit(1); /* the callee should have complained already */
303 ref_lock = lock_any_ref_for_update("HEAD", from, 0);
304 return write_ref_sha1(ref_lock, to, "cherry-pick");
305 }
306
307 static int do_recursive_merge(struct commit *base, struct commit *next,
308 const char *base_label, const char *next_label,
309 unsigned char *head, struct strbuf *msgbuf)
310 {
311 struct merge_options o;
312 struct tree *result, *next_tree, *base_tree, *head_tree;
313 int clean, index_fd;
314 static struct lock_file index_lock;
315
316 index_fd = hold_locked_index(&index_lock, 1);
317
318 read_cache();
319
320 /*
321 * NEEDSWORK: cherry-picking between branches with
322 * different end-of-line normalization is a pain;
323 * plumb in an option to set o.renormalize?
324 * (or better: arbitrary -X options)
325 */
326 init_merge_options(&o);
327 o.ancestor = base ? base_label : "(empty tree)";
328 o.branch1 = "HEAD";
329 o.branch2 = next ? next_label : "(empty tree)";
330
331 head_tree = parse_tree_indirect(head);
332 next_tree = next ? next->tree : empty_tree();
333 base_tree = base ? base->tree : empty_tree();
334
335 clean = merge_trees(&o,
336 head_tree,
337 next_tree, base_tree, &result);
338
339 if (active_cache_changed &&
340 (write_cache(index_fd, active_cache, active_nr) ||
341 commit_locked_index(&index_lock)))
342 die("%s: Unable to write new index file", me);
343 rollback_lock_file(&index_lock);
344
345 if (!clean) {
346 int i;
347 strbuf_addstr(msgbuf, "\nConflicts:\n\n");
348 for (i = 0; i < active_nr;) {
349 struct cache_entry *ce = active_cache[i++];
350 if (ce_stage(ce)) {
351 strbuf_addch(msgbuf, '\t');
352 strbuf_addstr(msgbuf, ce->name);
353 strbuf_addch(msgbuf, '\n');
354 while (i < active_nr && !strcmp(ce->name,
355 active_cache[i]->name))
356 i++;
357 }
358 }
359 }
360
361 return !clean;
362 }
363
364 /*
365 * If we are cherry-pick, and if the merge did not result in
366 * hand-editing, we will hit this commit and inherit the original
367 * author date and name.
368 * If we are revert, or if our cherry-pick results in a hand merge,
369 * we had better say that the current user is responsible for that.
370 */
371 static int run_git_commit(const char *defmsg)
372 {
373 /* 6 is max possible length of our args array including NULL */
374 const char *args[6];
375 int i = 0;
376
377 args[i++] = "commit";
378 args[i++] = "-n";
379 if (signoff)
380 args[i++] = "-s";
381 if (!edit) {
382 args[i++] = "-F";
383 args[i++] = defmsg;
384 }
385 args[i] = NULL;
386
387 return run_command_v_opt(args, RUN_GIT_CMD);
388 }
389
390 static int do_pick_commit(void)
391 {
392 unsigned char head[20];
393 struct commit *base, *next, *parent;
394 const char *base_label, *next_label;
395 struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
396 char *defmsg = NULL;
397 struct strbuf msgbuf = STRBUF_INIT;
398 int res;
399
400 if (no_commit) {
401 /*
402 * We do not intend to commit immediately. We just want to
403 * merge the differences in, so let's compute the tree
404 * that represents the "current" state for merge-recursive
405 * to work on.
406 */
407 if (write_cache_as_tree(head, 0, NULL))
408 die ("Your index file is unmerged.");
409 } else {
410 if (get_sha1("HEAD", head))
411 die ("You do not have a valid HEAD");
412 if (index_differs_from("HEAD", 0))
413 die_dirty_index(me);
414 }
415 discard_cache();
416
417 if (!commit->parents) {
418 if (action == REVERT)
419 die ("Cannot revert a root commit");
420 parent = NULL;
421 }
422 else if (commit->parents->next) {
423 /* Reverting or cherry-picking a merge commit */
424 int cnt;
425 struct commit_list *p;
426
427 if (!mainline)
428 die("Commit %s is a merge but no -m option was given.",
429 sha1_to_hex(commit->object.sha1));
430
431 for (cnt = 1, p = commit->parents;
432 cnt != mainline && p;
433 cnt++)
434 p = p->next;
435 if (cnt != mainline || !p)
436 die("Commit %s does not have parent %d",
437 sha1_to_hex(commit->object.sha1), mainline);
438 parent = p->item;
439 } else if (0 < mainline)
440 die("Mainline was specified but commit %s is not a merge.",
441 sha1_to_hex(commit->object.sha1));
442 else
443 parent = commit->parents->item;
444
445 if (allow_ff && parent && !hashcmp(parent->object.sha1, head))
446 return fast_forward_to(commit->object.sha1, head);
447
448 if (parent && parse_commit(parent) < 0)
449 die("%s: cannot parse parent commit %s",
450 me, sha1_to_hex(parent->object.sha1));
451
452 if (get_message(commit->buffer, &msg) != 0)
453 die("Cannot get commit message for %s",
454 sha1_to_hex(commit->object.sha1));
455
456 /*
457 * "commit" is an existing commit. We would want to apply
458 * the difference it introduces since its first parent "prev"
459 * on top of the current HEAD if we are cherry-pick. Or the
460 * reverse of it if we are revert.
461 */
462
463 defmsg = git_pathdup("MERGE_MSG");
464
465 if (action == REVERT) {
466 base = commit;
467 base_label = msg.label;
468 next = parent;
469 next_label = msg.parent_label;
470 strbuf_addstr(&msgbuf, "Revert \"");
471 strbuf_addstr(&msgbuf, msg.subject);
472 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
473 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
474
475 if (commit->parents->next) {
476 strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
477 strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
478 }
479 strbuf_addstr(&msgbuf, ".\n");
480 } else {
481 base = parent;
482 base_label = msg.parent_label;
483 next = commit;
484 next_label = msg.label;
485 set_author_ident_env(msg.message);
486 add_message_to_msg(&msgbuf, msg.message);
487 if (no_replay) {
488 strbuf_addstr(&msgbuf, "(cherry picked from commit ");
489 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
490 strbuf_addstr(&msgbuf, ")\n");
491 }
492 }
493
494 if (!strategy || !strcmp(strategy, "recursive") || action == REVERT) {
495 res = do_recursive_merge(base, next, base_label, next_label,
496 head, &msgbuf);
497 write_message(&msgbuf, defmsg);
498 } else {
499 struct commit_list *common = NULL;
500 struct commit_list *remotes = NULL;
501
502 write_message(&msgbuf, defmsg);
503
504 commit_list_insert(base, &common);
505 commit_list_insert(next, &remotes);
506 res = try_merge_command(strategy, common,
507 sha1_to_hex(head), remotes);
508 free_commit_list(common);
509 free_commit_list(remotes);
510 }
511
512 if (res) {
513 error("could not %s %s... %s",
514 action == REVERT ? "revert" : "apply",
515 find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV),
516 msg.subject);
517 print_advice();
518 rerere(allow_rerere_auto);
519 } else {
520 if (!no_commit)
521 res = run_git_commit(defmsg);
522 }
523
524 free_message(&msg);
525 free(defmsg);
526
527 return res;
528 }
529
530 static void prepare_revs(struct rev_info *revs)
531 {
532 int argc;
533
534 init_revisions(revs, NULL);
535 revs->no_walk = 1;
536 if (action != REVERT)
537 revs->reverse = 1;
538
539 argc = setup_revisions(commit_argc, commit_argv, revs, NULL);
540 if (argc > 1)
541 usage(*revert_or_cherry_pick_usage());
542
543 if (prepare_revision_walk(revs))
544 die("revision walk setup failed");
545
546 if (!revs->commits)
547 die("empty commit set passed");
548 }
549
550 static void read_and_refresh_cache(const char *me)
551 {
552 static struct lock_file index_lock;
553 int index_fd = hold_locked_index(&index_lock, 0);
554 if (read_index_preload(&the_index, NULL) < 0)
555 die("git %s: failed to read the index", me);
556 refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
557 if (the_index.cache_changed) {
558 if (write_index(&the_index, index_fd) ||
559 commit_locked_index(&index_lock))
560 die("git %s: failed to refresh the index", me);
561 }
562 rollback_lock_file(&index_lock);
563 }
564
565 static int revert_or_cherry_pick(int argc, const char **argv)
566 {
567 struct rev_info revs;
568
569 git_config(git_default_config, NULL);
570 me = action == REVERT ? "revert" : "cherry-pick";
571 setenv(GIT_REFLOG_ACTION, me, 0);
572 parse_args(argc, argv);
573
574 if (allow_ff) {
575 if (signoff)
576 die("cherry-pick --ff cannot be used with --signoff");
577 if (no_commit)
578 die("cherry-pick --ff cannot be used with --no-commit");
579 if (no_replay)
580 die("cherry-pick --ff cannot be used with -x");
581 if (edit)
582 die("cherry-pick --ff cannot be used with --edit");
583 }
584
585 read_and_refresh_cache(me);
586
587 prepare_revs(&revs);
588
589 while ((commit = get_revision(&revs))) {
590 int res = do_pick_commit();
591 if (res)
592 return res;
593 }
594
595 return 0;
596 }
597
598 int cmd_revert(int argc, const char **argv, const char *prefix)
599 {
600 if (isatty(0))
601 edit = 1;
602 action = REVERT;
603 return revert_or_cherry_pick(argc, argv);
604 }
605
606 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
607 {
608 action = CHERRY_PICK;
609 return revert_or_cherry_pick(argc, argv);
610 }