cherry-pick/revert: add support for -X/--strategy-option
[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
48 /* Merge strategy. */
49 static const char *strategy;
50 static const char **xopts;
51 static size_t xopts_nr, xopts_alloc;
52
53 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
54
55 static char *get_encoding(const char *message);
56
57 static const char * const *revert_or_cherry_pick_usage(void)
58 {
59 return action == REVERT ? revert_usage : cherry_pick_usage;
60 }
61
62 static int option_parse_x(const struct option *opt,
63 const char *arg, int unset)
64 {
65 if (unset)
66 return 0;
67
68 ALLOC_GROW(xopts, xopts_nr + 1, xopts_alloc);
69 xopts[xopts_nr++] = xstrdup(arg);
70 return 0;
71 }
72
73 static void parse_args(int argc, const char **argv)
74 {
75 const char * const * usage_str = revert_or_cherry_pick_usage();
76 int noop;
77 struct option options[] = {
78 OPT_BOOLEAN('n', "no-commit", &no_commit, "don't automatically commit"),
79 OPT_BOOLEAN('e', "edit", &edit, "edit the commit message"),
80 OPT_BOOLEAN('r', NULL, &noop, "no-op (backward compatibility)"),
81 OPT_BOOLEAN('s', "signoff", &signoff, "add Signed-off-by:"),
82 OPT_INTEGER('m', "mainline", &mainline, "parent number"),
83 OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
84 OPT_STRING(0, "strategy", &strategy, "strategy", "merge strategy"),
85 OPT_CALLBACK('X', "strategy-option", &xopts, "option",
86 "option for merge strategy", option_parse_x),
87 OPT_END(),
88 OPT_END(),
89 OPT_END(),
90 };
91
92 if (action == CHERRY_PICK) {
93 struct option cp_extra[] = {
94 OPT_BOOLEAN('x', NULL, &no_replay, "append commit name"),
95 OPT_BOOLEAN(0, "ff", &allow_ff, "allow fast-forward"),
96 OPT_END(),
97 };
98 if (parse_options_concat(options, ARRAY_SIZE(options), cp_extra))
99 die("program error");
100 }
101
102 commit_argc = parse_options(argc, argv, NULL, options, usage_str,
103 PARSE_OPT_KEEP_ARGV0 |
104 PARSE_OPT_KEEP_UNKNOWN);
105 if (commit_argc < 2)
106 usage_with_options(usage_str, options);
107
108 commit_argv = argv;
109 }
110
111 struct commit_message {
112 char *parent_label;
113 const char *label;
114 const char *subject;
115 char *reencoded_message;
116 const char *message;
117 };
118
119 static int get_message(const char *raw_message, struct commit_message *out)
120 {
121 const char *encoding;
122 const char *abbrev, *subject;
123 int abbrev_len, subject_len;
124 char *q;
125
126 if (!raw_message)
127 return -1;
128 encoding = get_encoding(raw_message);
129 if (!encoding)
130 encoding = "UTF-8";
131 if (!git_commit_encoding)
132 git_commit_encoding = "UTF-8";
133
134 out->reencoded_message = NULL;
135 out->message = raw_message;
136 if (strcmp(encoding, git_commit_encoding))
137 out->reencoded_message = reencode_string(raw_message,
138 git_commit_encoding, encoding);
139 if (out->reencoded_message)
140 out->message = out->reencoded_message;
141
142 abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
143 abbrev_len = strlen(abbrev);
144
145 subject_len = find_commit_subject(out->message, &subject);
146
147 out->parent_label = xmalloc(strlen("parent of ") + abbrev_len +
148 strlen("... ") + subject_len + 1);
149 q = out->parent_label;
150 q = mempcpy(q, "parent of ", strlen("parent of "));
151 out->label = q;
152 q = mempcpy(q, abbrev, abbrev_len);
153 q = mempcpy(q, "... ", strlen("... "));
154 out->subject = q;
155 q = mempcpy(q, subject, subject_len);
156 *q = '\0';
157 return 0;
158 }
159
160 static void free_message(struct commit_message *msg)
161 {
162 free(msg->parent_label);
163 free(msg->reencoded_message);
164 }
165
166 static char *get_encoding(const char *message)
167 {
168 const char *p = message, *eol;
169
170 if (!p)
171 die ("Could not read commit message of %s",
172 sha1_to_hex(commit->object.sha1));
173 while (*p && *p != '\n') {
174 for (eol = p + 1; *eol && *eol != '\n'; eol++)
175 ; /* do nothing */
176 if (!prefixcmp(p, "encoding ")) {
177 char *result = xmalloc(eol - 8 - p);
178 strlcpy(result, p + 9, eol - 8 - p);
179 return result;
180 }
181 p = eol;
182 if (*p == '\n')
183 p++;
184 }
185 return NULL;
186 }
187
188 static void add_message_to_msg(struct strbuf *msgbuf, const char *message)
189 {
190 const char *p = message;
191 while (*p && (*p != '\n' || p[1] != '\n'))
192 p++;
193
194 if (!*p)
195 strbuf_addstr(msgbuf, sha1_to_hex(commit->object.sha1));
196
197 p += 2;
198 strbuf_addstr(msgbuf, p);
199 }
200
201 static void set_author_ident_env(const char *message)
202 {
203 const char *p = message;
204 if (!p)
205 die ("Could not read commit message of %s",
206 sha1_to_hex(commit->object.sha1));
207 while (*p && *p != '\n') {
208 const char *eol;
209
210 for (eol = p; *eol && *eol != '\n'; eol++)
211 ; /* do nothing */
212 if (!prefixcmp(p, "author ")) {
213 char *line, *pend, *email, *timestamp;
214
215 p += 7;
216 line = xmemdupz(p, eol - p);
217 email = strchr(line, '<');
218 if (!email)
219 die ("Could not extract author email from %s",
220 sha1_to_hex(commit->object.sha1));
221 if (email == line)
222 pend = line;
223 else
224 for (pend = email; pend != line + 1 &&
225 isspace(pend[-1]); pend--);
226 ; /* do nothing */
227 *pend = '\0';
228 email++;
229 timestamp = strchr(email, '>');
230 if (!timestamp)
231 die ("Could not extract author time from %s",
232 sha1_to_hex(commit->object.sha1));
233 *timestamp = '\0';
234 for (timestamp++; *timestamp && isspace(*timestamp);
235 timestamp++)
236 ; /* do nothing */
237 setenv("GIT_AUTHOR_NAME", line, 1);
238 setenv("GIT_AUTHOR_EMAIL", email, 1);
239 setenv("GIT_AUTHOR_DATE", timestamp, 1);
240 free(line);
241 return;
242 }
243 p = eol;
244 if (*p == '\n')
245 p++;
246 }
247 die ("No author information found in %s",
248 sha1_to_hex(commit->object.sha1));
249 }
250
251 static void advise(const char *advice, ...)
252 {
253 va_list params;
254
255 va_start(params, advice);
256 vreportf("hint: ", advice, params);
257 va_end(params);
258 }
259
260 static void print_advice(void)
261 {
262 char *msg = getenv("GIT_CHERRY_PICK_HELP");
263
264 if (msg) {
265 fprintf(stderr, "%s\n", msg);
266 return;
267 }
268
269 advise("after resolving the conflicts, mark the corrected paths");
270 advise("with 'git add <paths>' or 'git rm <paths>'");
271
272 if (action == CHERRY_PICK)
273 advise("and commit the result with 'git commit -c %s'",
274 find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
275 }
276
277 static void write_message(struct strbuf *msgbuf, const char *filename)
278 {
279 static struct lock_file msg_file;
280
281 int msg_fd = hold_lock_file_for_update(&msg_file, filename,
282 LOCK_DIE_ON_ERROR);
283 if (write_in_full(msg_fd, msgbuf->buf, msgbuf->len) < 0)
284 die_errno("Could not write to %s.", filename);
285 strbuf_release(msgbuf);
286 if (commit_lock_file(&msg_file) < 0)
287 die("Error wrapping up %s", filename);
288 }
289
290 static struct tree *empty_tree(void)
291 {
292 struct tree *tree = xcalloc(1, sizeof(struct tree));
293
294 tree->object.parsed = 1;
295 tree->object.type = OBJ_TREE;
296 pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
297 return tree;
298 }
299
300 static NORETURN void die_dirty_index(const char *me)
301 {
302 if (read_cache_unmerged()) {
303 die_resolve_conflict(me);
304 } else {
305 if (advice_commit_before_merge)
306 die("Your local changes would be overwritten by %s.\n"
307 "Please, commit your changes or stash them to proceed.", me);
308 else
309 die("Your local changes would be overwritten by %s.\n", me);
310 }
311 }
312
313 static int fast_forward_to(const unsigned char *to, const unsigned char *from)
314 {
315 struct ref_lock *ref_lock;
316
317 read_cache();
318 if (checkout_fast_forward(from, to))
319 exit(1); /* the callee should have complained already */
320 ref_lock = lock_any_ref_for_update("HEAD", from, 0);
321 return write_ref_sha1(ref_lock, to, "cherry-pick");
322 }
323
324 static int do_recursive_merge(struct commit *base, struct commit *next,
325 const char *base_label, const char *next_label,
326 unsigned char *head, struct strbuf *msgbuf)
327 {
328 struct merge_options o;
329 struct tree *result, *next_tree, *base_tree, *head_tree;
330 int clean, index_fd;
331 const char **xopt;
332 static struct lock_file index_lock;
333
334 index_fd = hold_locked_index(&index_lock, 1);
335
336 read_cache();
337
338 init_merge_options(&o);
339 o.ancestor = base ? base_label : "(empty tree)";
340 o.branch1 = "HEAD";
341 o.branch2 = next ? next_label : "(empty tree)";
342
343 head_tree = parse_tree_indirect(head);
344 next_tree = next ? next->tree : empty_tree();
345 base_tree = base ? base->tree : empty_tree();
346
347 for (xopt = xopts; xopt != xopts + xopts_nr; xopt++)
348 parse_merge_opt(&o, *xopt);
349
350 clean = merge_trees(&o,
351 head_tree,
352 next_tree, base_tree, &result);
353
354 if (active_cache_changed &&
355 (write_cache(index_fd, active_cache, active_nr) ||
356 commit_locked_index(&index_lock)))
357 die("%s: Unable to write new index file", me);
358 rollback_lock_file(&index_lock);
359
360 if (!clean) {
361 int i;
362 strbuf_addstr(msgbuf, "\nConflicts:\n\n");
363 for (i = 0; i < active_nr;) {
364 struct cache_entry *ce = active_cache[i++];
365 if (ce_stage(ce)) {
366 strbuf_addch(msgbuf, '\t');
367 strbuf_addstr(msgbuf, ce->name);
368 strbuf_addch(msgbuf, '\n');
369 while (i < active_nr && !strcmp(ce->name,
370 active_cache[i]->name))
371 i++;
372 }
373 }
374 }
375
376 return !clean;
377 }
378
379 /*
380 * If we are cherry-pick, and if the merge did not result in
381 * hand-editing, we will hit this commit and inherit the original
382 * author date and name.
383 * If we are revert, or if our cherry-pick results in a hand merge,
384 * we had better say that the current user is responsible for that.
385 */
386 static int run_git_commit(const char *defmsg)
387 {
388 /* 6 is max possible length of our args array including NULL */
389 const char *args[6];
390 int i = 0;
391
392 args[i++] = "commit";
393 args[i++] = "-n";
394 if (signoff)
395 args[i++] = "-s";
396 if (!edit) {
397 args[i++] = "-F";
398 args[i++] = defmsg;
399 }
400 args[i] = NULL;
401
402 return run_command_v_opt(args, RUN_GIT_CMD);
403 }
404
405 static int do_pick_commit(void)
406 {
407 unsigned char head[20];
408 struct commit *base, *next, *parent;
409 const char *base_label, *next_label;
410 struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
411 char *defmsg = NULL;
412 struct strbuf msgbuf = STRBUF_INIT;
413 int res;
414
415 if (no_commit) {
416 /*
417 * We do not intend to commit immediately. We just want to
418 * merge the differences in, so let's compute the tree
419 * that represents the "current" state for merge-recursive
420 * to work on.
421 */
422 if (write_cache_as_tree(head, 0, NULL))
423 die ("Your index file is unmerged.");
424 } else {
425 if (get_sha1("HEAD", head))
426 die ("You do not have a valid HEAD");
427 if (index_differs_from("HEAD", 0))
428 die_dirty_index(me);
429 }
430 discard_cache();
431
432 if (!commit->parents) {
433 if (action == REVERT)
434 die ("Cannot revert a root commit");
435 parent = NULL;
436 }
437 else if (commit->parents->next) {
438 /* Reverting or cherry-picking a merge commit */
439 int cnt;
440 struct commit_list *p;
441
442 if (!mainline)
443 die("Commit %s is a merge but no -m option was given.",
444 sha1_to_hex(commit->object.sha1));
445
446 for (cnt = 1, p = commit->parents;
447 cnt != mainline && p;
448 cnt++)
449 p = p->next;
450 if (cnt != mainline || !p)
451 die("Commit %s does not have parent %d",
452 sha1_to_hex(commit->object.sha1), mainline);
453 parent = p->item;
454 } else if (0 < mainline)
455 die("Mainline was specified but commit %s is not a merge.",
456 sha1_to_hex(commit->object.sha1));
457 else
458 parent = commit->parents->item;
459
460 if (allow_ff && parent && !hashcmp(parent->object.sha1, head))
461 return fast_forward_to(commit->object.sha1, head);
462
463 if (parent && parse_commit(parent) < 0)
464 die("%s: cannot parse parent commit %s",
465 me, sha1_to_hex(parent->object.sha1));
466
467 if (get_message(commit->buffer, &msg) != 0)
468 die("Cannot get commit message for %s",
469 sha1_to_hex(commit->object.sha1));
470
471 /*
472 * "commit" is an existing commit. We would want to apply
473 * the difference it introduces since its first parent "prev"
474 * on top of the current HEAD if we are cherry-pick. Or the
475 * reverse of it if we are revert.
476 */
477
478 defmsg = git_pathdup("MERGE_MSG");
479
480 if (action == REVERT) {
481 base = commit;
482 base_label = msg.label;
483 next = parent;
484 next_label = msg.parent_label;
485 strbuf_addstr(&msgbuf, "Revert \"");
486 strbuf_addstr(&msgbuf, msg.subject);
487 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
488 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
489
490 if (commit->parents->next) {
491 strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
492 strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
493 }
494 strbuf_addstr(&msgbuf, ".\n");
495 } else {
496 base = parent;
497 base_label = msg.parent_label;
498 next = commit;
499 next_label = msg.label;
500 set_author_ident_env(msg.message);
501 add_message_to_msg(&msgbuf, msg.message);
502 if (no_replay) {
503 strbuf_addstr(&msgbuf, "(cherry picked from commit ");
504 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
505 strbuf_addstr(&msgbuf, ")\n");
506 }
507 }
508
509 if (!strategy || !strcmp(strategy, "recursive") || action == REVERT) {
510 res = do_recursive_merge(base, next, base_label, next_label,
511 head, &msgbuf);
512 write_message(&msgbuf, defmsg);
513 } else {
514 struct commit_list *common = NULL;
515 struct commit_list *remotes = NULL;
516
517 write_message(&msgbuf, defmsg);
518
519 commit_list_insert(base, &common);
520 commit_list_insert(next, &remotes);
521 res = try_merge_command(strategy, xopts_nr, xopts, common,
522 sha1_to_hex(head), remotes);
523 free_commit_list(common);
524 free_commit_list(remotes);
525 }
526
527 if (res) {
528 error("could not %s %s... %s",
529 action == REVERT ? "revert" : "apply",
530 find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV),
531 msg.subject);
532 print_advice();
533 rerere(allow_rerere_auto);
534 } else {
535 if (!no_commit)
536 res = run_git_commit(defmsg);
537 }
538
539 free_message(&msg);
540 free(defmsg);
541
542 return res;
543 }
544
545 static void prepare_revs(struct rev_info *revs)
546 {
547 int argc;
548
549 init_revisions(revs, NULL);
550 revs->no_walk = 1;
551 if (action != REVERT)
552 revs->reverse = 1;
553
554 argc = setup_revisions(commit_argc, commit_argv, revs, NULL);
555 if (argc > 1)
556 usage(*revert_or_cherry_pick_usage());
557
558 if (prepare_revision_walk(revs))
559 die("revision walk setup failed");
560
561 if (!revs->commits)
562 die("empty commit set passed");
563 }
564
565 static void read_and_refresh_cache(const char *me)
566 {
567 static struct lock_file index_lock;
568 int index_fd = hold_locked_index(&index_lock, 0);
569 if (read_index_preload(&the_index, NULL) < 0)
570 die("git %s: failed to read the index", me);
571 refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
572 if (the_index.cache_changed) {
573 if (write_index(&the_index, index_fd) ||
574 commit_locked_index(&index_lock))
575 die("git %s: failed to refresh the index", me);
576 }
577 rollback_lock_file(&index_lock);
578 }
579
580 static int revert_or_cherry_pick(int argc, const char **argv)
581 {
582 struct rev_info revs;
583
584 git_config(git_default_config, NULL);
585 me = action == REVERT ? "revert" : "cherry-pick";
586 setenv(GIT_REFLOG_ACTION, me, 0);
587 parse_args(argc, argv);
588
589 if (allow_ff) {
590 if (signoff)
591 die("cherry-pick --ff cannot be used with --signoff");
592 if (no_commit)
593 die("cherry-pick --ff cannot be used with --no-commit");
594 if (no_replay)
595 die("cherry-pick --ff cannot be used with -x");
596 if (edit)
597 die("cherry-pick --ff cannot be used with --edit");
598 }
599
600 read_and_refresh_cache(me);
601
602 prepare_revs(&revs);
603
604 while ((commit = get_revision(&revs))) {
605 int res = do_pick_commit();
606 if (res)
607 return res;
608 }
609
610 return 0;
611 }
612
613 int cmd_revert(int argc, const char **argv, const char *prefix)
614 {
615 if (isatty(0))
616 edit = 1;
617 action = REVERT;
618 return revert_or_cherry_pick(argc, argv);
619 }
620
621 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
622 {
623 action = CHERRY_PICK;
624 return revert_or_cherry_pick(argc, argv);
625 }