Introduce CHERRY_PICK_HEAD
[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 write_cherry_pick_head(void)
235 {
236 int fd;
237 struct strbuf buf = STRBUF_INIT;
238
239 strbuf_addf(&buf, "%s\n", sha1_to_hex(commit->object.sha1));
240
241 fd = open(git_path("CHERRY_PICK_HEAD"), O_WRONLY | O_CREAT, 0666);
242 if (fd < 0)
243 die_errno("Could not open '%s' for writing",
244 git_path("CHERRY_PICK_HEAD"));
245 if (write_in_full(fd, buf.buf, buf.len) != buf.len || close(fd))
246 die_errno("Could not write to '%s'", git_path("CHERRY_PICK_HEAD"));
247 strbuf_release(&buf);
248 }
249
250 static void advise(const char *advice, ...)
251 {
252 va_list params;
253
254 va_start(params, advice);
255 vreportf("hint: ", advice, params);
256 va_end(params);
257 }
258
259 static void print_advice(void)
260 {
261 char *msg = getenv("GIT_CHERRY_PICK_HELP");
262
263 if (msg) {
264 fprintf(stderr, "%s\n", msg);
265 /*
266 * A conflict has occured but the porcelain
267 * (typically rebase --interactive) wants to take care
268 * of the commit itself so remove CHERRY_PICK_HEAD
269 */
270 unlink(git_path("CHERRY_PICK_HEAD"));
271 return;
272 }
273
274 advise("after resolving the conflicts, mark the corrected paths");
275 advise("with 'git add <paths>' or 'git rm <paths>'");
276
277 if (action == CHERRY_PICK)
278 advise("and commit the result with 'git commit -c CHERRY_PICK_HEAD'");
279 }
280
281 static void write_message(struct strbuf *msgbuf, const char *filename)
282 {
283 static struct lock_file msg_file;
284
285 int msg_fd = hold_lock_file_for_update(&msg_file, filename,
286 LOCK_DIE_ON_ERROR);
287 if (write_in_full(msg_fd, msgbuf->buf, msgbuf->len) < 0)
288 die_errno("Could not write to %s.", filename);
289 strbuf_release(msgbuf);
290 if (commit_lock_file(&msg_file) < 0)
291 die("Error wrapping up %s", filename);
292 }
293
294 static struct tree *empty_tree(void)
295 {
296 struct tree *tree = xcalloc(1, sizeof(struct tree));
297
298 tree->object.parsed = 1;
299 tree->object.type = OBJ_TREE;
300 pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
301 return tree;
302 }
303
304 static NORETURN void die_dirty_index(const char *me)
305 {
306 if (read_cache_unmerged()) {
307 die_resolve_conflict(me);
308 } else {
309 if (advice_commit_before_merge)
310 die("Your local changes would be overwritten by %s.\n"
311 "Please, commit your changes or stash them to proceed.", me);
312 else
313 die("Your local changes would be overwritten by %s.\n", me);
314 }
315 }
316
317 static int fast_forward_to(const unsigned char *to, const unsigned char *from)
318 {
319 struct ref_lock *ref_lock;
320
321 read_cache();
322 if (checkout_fast_forward(from, to))
323 exit(1); /* the callee should have complained already */
324 ref_lock = lock_any_ref_for_update("HEAD", from, 0);
325 return write_ref_sha1(ref_lock, to, "cherry-pick");
326 }
327
328 static int do_recursive_merge(struct commit *base, struct commit *next,
329 const char *base_label, const char *next_label,
330 unsigned char *head, struct strbuf *msgbuf)
331 {
332 struct merge_options o;
333 struct tree *result, *next_tree, *base_tree, *head_tree;
334 int clean, index_fd;
335 static struct lock_file index_lock;
336
337 index_fd = hold_locked_index(&index_lock, 1);
338
339 read_cache();
340
341 /*
342 * NEEDSWORK: cherry-picking between branches with
343 * different end-of-line normalization is a pain;
344 * plumb in an option to set o.renormalize?
345 * (or better: arbitrary -X options)
346 */
347 init_merge_options(&o);
348 o.ancestor = base ? base_label : "(empty tree)";
349 o.branch1 = "HEAD";
350 o.branch2 = next ? next_label : "(empty tree)";
351
352 head_tree = parse_tree_indirect(head);
353 next_tree = next ? next->tree : empty_tree();
354 base_tree = base ? base->tree : empty_tree();
355
356 clean = merge_trees(&o,
357 head_tree,
358 next_tree, base_tree, &result);
359
360 if (active_cache_changed &&
361 (write_cache(index_fd, active_cache, active_nr) ||
362 commit_locked_index(&index_lock)))
363 die("%s: Unable to write new index file", me);
364 rollback_lock_file(&index_lock);
365
366 if (!clean) {
367 int i;
368 strbuf_addstr(msgbuf, "\nConflicts:\n\n");
369 for (i = 0; i < active_nr;) {
370 struct cache_entry *ce = active_cache[i++];
371 if (ce_stage(ce)) {
372 strbuf_addch(msgbuf, '\t');
373 strbuf_addstr(msgbuf, ce->name);
374 strbuf_addch(msgbuf, '\n');
375 while (i < active_nr && !strcmp(ce->name,
376 active_cache[i]->name))
377 i++;
378 }
379 }
380 }
381
382 return !clean;
383 }
384
385 /*
386 * If we are cherry-pick, and if the merge did not result in
387 * hand-editing, we will hit this commit and inherit the original
388 * author date and name.
389 * If we are revert, or if our cherry-pick results in a hand merge,
390 * we had better say that the current user is responsible for that.
391 */
392 static int run_git_commit(const char *defmsg)
393 {
394 /* 6 is max possible length of our args array including NULL */
395 const char *args[6];
396 int i = 0;
397
398 args[i++] = "commit";
399 args[i++] = "-n";
400 if (signoff)
401 args[i++] = "-s";
402 if (!edit) {
403 args[i++] = "-F";
404 args[i++] = defmsg;
405 }
406 args[i] = NULL;
407
408 return run_command_v_opt(args, RUN_GIT_CMD);
409 }
410
411 static int do_pick_commit(void)
412 {
413 unsigned char head[20];
414 struct commit *base, *next, *parent;
415 const char *base_label, *next_label;
416 struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
417 char *defmsg = NULL;
418 struct strbuf msgbuf = STRBUF_INIT;
419 int res;
420
421 if (no_commit) {
422 /*
423 * We do not intend to commit immediately. We just want to
424 * merge the differences in, so let's compute the tree
425 * that represents the "current" state for merge-recursive
426 * to work on.
427 */
428 if (write_cache_as_tree(head, 0, NULL))
429 die ("Your index file is unmerged.");
430 } else {
431 if (get_sha1("HEAD", head))
432 die ("You do not have a valid HEAD");
433 if (index_differs_from("HEAD", 0))
434 die_dirty_index(me);
435 }
436 discard_cache();
437
438 if (!commit->parents) {
439 if (action == REVERT)
440 die ("Cannot revert a root commit");
441 parent = NULL;
442 }
443 else if (commit->parents->next) {
444 /* Reverting or cherry-picking a merge commit */
445 int cnt;
446 struct commit_list *p;
447
448 if (!mainline)
449 die("Commit %s is a merge but no -m option was given.",
450 sha1_to_hex(commit->object.sha1));
451
452 for (cnt = 1, p = commit->parents;
453 cnt != mainline && p;
454 cnt++)
455 p = p->next;
456 if (cnt != mainline || !p)
457 die("Commit %s does not have parent %d",
458 sha1_to_hex(commit->object.sha1), mainline);
459 parent = p->item;
460 } else if (0 < mainline)
461 die("Mainline was specified but commit %s is not a merge.",
462 sha1_to_hex(commit->object.sha1));
463 else
464 parent = commit->parents->item;
465
466 if (allow_ff && parent && !hashcmp(parent->object.sha1, head))
467 return fast_forward_to(commit->object.sha1, head);
468
469 if (parent && parse_commit(parent) < 0)
470 die("%s: cannot parse parent commit %s",
471 me, sha1_to_hex(parent->object.sha1));
472
473 if (get_message(commit->buffer, &msg) != 0)
474 die("Cannot get commit message for %s",
475 sha1_to_hex(commit->object.sha1));
476
477 /*
478 * "commit" is an existing commit. We would want to apply
479 * the difference it introduces since its first parent "prev"
480 * on top of the current HEAD if we are cherry-pick. Or the
481 * reverse of it if we are revert.
482 */
483
484 defmsg = git_pathdup("MERGE_MSG");
485
486 if (action == REVERT) {
487 base = commit;
488 base_label = msg.label;
489 next = parent;
490 next_label = msg.parent_label;
491 strbuf_addstr(&msgbuf, "Revert \"");
492 strbuf_addstr(&msgbuf, msg.subject);
493 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
494 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
495
496 if (commit->parents->next) {
497 strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
498 strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
499 }
500 strbuf_addstr(&msgbuf, ".\n");
501 } else {
502 base = parent;
503 base_label = msg.parent_label;
504 next = commit;
505 next_label = msg.label;
506 set_author_ident_env(msg.message);
507 add_message_to_msg(&msgbuf, msg.message);
508 if (no_replay) {
509 strbuf_addstr(&msgbuf, "(cherry picked from commit ");
510 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
511 strbuf_addstr(&msgbuf, ")\n");
512 }
513 if (!no_commit)
514 write_cherry_pick_head();
515 }
516
517 if (!strategy || !strcmp(strategy, "recursive") || action == REVERT) {
518 res = do_recursive_merge(base, next, base_label, next_label,
519 head, &msgbuf);
520 write_message(&msgbuf, defmsg);
521 } else {
522 struct commit_list *common = NULL;
523 struct commit_list *remotes = NULL;
524
525 write_message(&msgbuf, defmsg);
526
527 commit_list_insert(base, &common);
528 commit_list_insert(next, &remotes);
529 res = try_merge_command(strategy, common,
530 sha1_to_hex(head), remotes);
531 free_commit_list(common);
532 free_commit_list(remotes);
533 }
534
535 if (res) {
536 error("could not %s %s... %s",
537 action == REVERT ? "revert" : "apply",
538 find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV),
539 msg.subject);
540 print_advice();
541 rerere(allow_rerere_auto);
542 } else {
543 if (!no_commit)
544 res = run_git_commit(defmsg);
545 }
546
547 free_message(&msg);
548 free(defmsg);
549
550 return res;
551 }
552
553 static void prepare_revs(struct rev_info *revs)
554 {
555 int argc;
556
557 init_revisions(revs, NULL);
558 revs->no_walk = 1;
559 if (action != REVERT)
560 revs->reverse = 1;
561
562 argc = setup_revisions(commit_argc, commit_argv, revs, NULL);
563 if (argc > 1)
564 usage(*revert_or_cherry_pick_usage());
565
566 if (prepare_revision_walk(revs))
567 die("revision walk setup failed");
568
569 if (!revs->commits)
570 die("empty commit set passed");
571 }
572
573 static void read_and_refresh_cache(const char *me)
574 {
575 static struct lock_file index_lock;
576 int index_fd = hold_locked_index(&index_lock, 0);
577 if (read_index_preload(&the_index, NULL) < 0)
578 die("git %s: failed to read the index", me);
579 refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
580 if (the_index.cache_changed) {
581 if (write_index(&the_index, index_fd) ||
582 commit_locked_index(&index_lock))
583 die("git %s: failed to refresh the index", me);
584 }
585 rollback_lock_file(&index_lock);
586 }
587
588 static int revert_or_cherry_pick(int argc, const char **argv)
589 {
590 struct rev_info revs;
591
592 git_config(git_default_config, NULL);
593 me = action == REVERT ? "revert" : "cherry-pick";
594 setenv(GIT_REFLOG_ACTION, me, 0);
595 parse_args(argc, argv);
596
597 if (allow_ff) {
598 if (signoff)
599 die("cherry-pick --ff cannot be used with --signoff");
600 if (no_commit)
601 die("cherry-pick --ff cannot be used with --no-commit");
602 if (no_replay)
603 die("cherry-pick --ff cannot be used with -x");
604 if (edit)
605 die("cherry-pick --ff cannot be used with --edit");
606 }
607
608 read_and_refresh_cache(me);
609
610 prepare_revs(&revs);
611
612 while ((commit = get_revision(&revs))) {
613 int res = do_pick_commit();
614 if (res)
615 return res;
616 }
617
618 return 0;
619 }
620
621 int cmd_revert(int argc, const char **argv, const char *prefix)
622 {
623 if (isatty(0))
624 edit = 1;
625 action = REVERT;
626 return revert_or_cherry_pick(argc, argv);
627 }
628
629 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
630 {
631 action = CHERRY_PICK;
632 return revert_or_cherry_pick(argc, argv);
633 }