Merge pull request from jiangxin/master
[git] / sequencer.c
1 #include "cache.h"
2 #include "sequencer.h"
3 #include "dir.h"
4 #include "object.h"
5 #include "commit.h"
6 #include "tag.h"
7 #include "run-command.h"
8 #include "exec_cmd.h"
9 #include "utf8.h"
10 #include "cache-tree.h"
11 #include "diff.h"
12 #include "revision.h"
13 #include "rerere.h"
14 #include "merge-recursive.h"
15 #include "refs.h"
16
17 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
18
19 void remove_sequencer_state(void)
20 {
21         struct strbuf seq_dir = STRBUF_INIT;
22
23         strbuf_addf(&seq_dir, "%s", git_path(SEQ_DIR));
24         remove_dir_recursively(&seq_dir, 0);
25         strbuf_release(&seq_dir);
26 }
27
28 static const char *action_name(const struct replay_opts *opts)
29 {
30         return opts->action == REPLAY_REVERT ? "revert" : "cherry-pick";
31 }
32
33 static char *get_encoding(const char *message);
34
35 struct commit_message {
36         char *parent_label;
37         const char *label;
38         const char *subject;
39         char *reencoded_message;
40         const char *message;
41 };
42
43 static int get_message(struct commit *commit, struct commit_message *out)
44 {
45         const char *encoding;
46         const char *abbrev, *subject;
47         int abbrev_len, subject_len;
48         char *q;
49
50         if (!commit->buffer)
51                 return -1;
52         encoding = get_encoding(commit->buffer);
53         if (!encoding)
54                 encoding = "UTF-8";
55         if (!git_commit_encoding)
56                 git_commit_encoding = "UTF-8";
57
58         out->reencoded_message = NULL;
59         out->message = commit->buffer;
60         if (strcmp(encoding, git_commit_encoding))
61                 out->reencoded_message = reencode_string(commit->buffer,
62                                         git_commit_encoding, encoding);
63         if (out->reencoded_message)
64                 out->message = out->reencoded_message;
65
66         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
67         abbrev_len = strlen(abbrev);
68
69         subject_len = find_commit_subject(out->message, &subject);
70
71         out->parent_label = xmalloc(strlen("parent of ") + abbrev_len +
72                               strlen("... ") + subject_len + 1);
73         q = out->parent_label;
74         q = mempcpy(q, "parent of ", strlen("parent of "));
75         out->label = q;
76         q = mempcpy(q, abbrev, abbrev_len);
77         q = mempcpy(q, "... ", strlen("... "));
78         out->subject = q;
79         q = mempcpy(q, subject, subject_len);
80         *q = '\0';
81         return 0;
82 }
83
84 static void free_message(struct commit_message *msg)
85 {
86         free(msg->parent_label);
87         free(msg->reencoded_message);
88 }
89
90 static char *get_encoding(const char *message)
91 {
92         const char *p = message, *eol;
93
94         while (*p && *p != '\n') {
95                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
96                         ; /* do nothing */
97                 if (!prefixcmp(p, "encoding ")) {
98                         char *result = xmalloc(eol - 8 - p);
99                         strlcpy(result, p + 9, eol - 8 - p);
100                         return result;
101                 }
102                 p = eol;
103                 if (*p == '\n')
104                         p++;
105         }
106         return NULL;
107 }
108
109 static void write_cherry_pick_head(struct commit *commit, const char *pseudoref)
110 {
111         const char *filename;
112         int fd;
113         struct strbuf buf = STRBUF_INIT;
114
115         strbuf_addf(&buf, "%s\n", sha1_to_hex(commit->object.sha1));
116
117         filename = git_path("%s", pseudoref);
118         fd = open(filename, O_WRONLY | O_CREAT, 0666);
119         if (fd < 0)
120                 die_errno(_("Could not open '%s' for writing"), filename);
121         if (write_in_full(fd, buf.buf, buf.len) != buf.len || close(fd))
122                 die_errno(_("Could not write to '%s'"), filename);
123         strbuf_release(&buf);
124 }
125
126 static void print_advice(int show_hint)
127 {
128         char *msg = getenv("GIT_CHERRY_PICK_HELP");
129
130         if (msg) {
131                 fprintf(stderr, "%s\n", msg);
132                 /*
133                  * A conflict has occured but the porcelain
134                  * (typically rebase --interactive) wants to take care
135                  * of the commit itself so remove CHERRY_PICK_HEAD
136                  */
137                 unlink(git_path("CHERRY_PICK_HEAD"));
138                 return;
139         }
140
141         if (show_hint)
142                 advise(_("after resolving the conflicts, mark the corrected paths\n"
143                          "with 'git add <paths>' or 'git rm <paths>'\n"
144                          "and commit the result with 'git commit'"));
145 }
146
147 static void write_message(struct strbuf *msgbuf, const char *filename)
148 {
149         static struct lock_file msg_file;
150
151         int msg_fd = hold_lock_file_for_update(&msg_file, filename,
152                                                LOCK_DIE_ON_ERROR);
153         if (write_in_full(msg_fd, msgbuf->buf, msgbuf->len) < 0)
154                 die_errno(_("Could not write to %s"), filename);
155         strbuf_release(msgbuf);
156         if (commit_lock_file(&msg_file) < 0)
157                 die(_("Error wrapping up %s"), filename);
158 }
159
160 static struct tree *empty_tree(void)
161 {
162         return lookup_tree((const unsigned char *)EMPTY_TREE_SHA1_BIN);
163 }
164
165 static int error_dirty_index(struct replay_opts *opts)
166 {
167         if (read_cache_unmerged())
168                 return error_resolve_conflict(action_name(opts));
169
170         /* Different translation strings for cherry-pick and revert */
171         if (opts->action == REPLAY_PICK)
172                 error(_("Your local changes would be overwritten by cherry-pick."));
173         else
174                 error(_("Your local changes would be overwritten by revert."));
175
176         if (advice_commit_before_merge)
177                 advise(_("Commit your changes or stash them to proceed."));
178         return -1;
179 }
180
181 static int fast_forward_to(const unsigned char *to, const unsigned char *from)
182 {
183         struct ref_lock *ref_lock;
184
185         read_cache();
186         if (checkout_fast_forward(from, to))
187                 exit(1); /* the callee should have complained already */
188         ref_lock = lock_any_ref_for_update("HEAD", from, 0);
189         return write_ref_sha1(ref_lock, to, "cherry-pick");
190 }
191
192 static int do_recursive_merge(struct commit *base, struct commit *next,
193                               const char *base_label, const char *next_label,
194                               unsigned char *head, struct strbuf *msgbuf,
195                               struct replay_opts *opts)
196 {
197         struct merge_options o;
198         struct tree *result, *next_tree, *base_tree, *head_tree;
199         int clean, index_fd;
200         const char **xopt;
201         static struct lock_file index_lock;
202
203         index_fd = hold_locked_index(&index_lock, 1);
204
205         read_cache();
206
207         init_merge_options(&o);
208         o.ancestor = base ? base_label : "(empty tree)";
209         o.branch1 = "HEAD";
210         o.branch2 = next ? next_label : "(empty tree)";
211
212         head_tree = parse_tree_indirect(head);
213         next_tree = next ? next->tree : empty_tree();
214         base_tree = base ? base->tree : empty_tree();
215
216         for (xopt = opts->xopts; xopt != opts->xopts + opts->xopts_nr; xopt++)
217                 parse_merge_opt(&o, *xopt);
218
219         clean = merge_trees(&o,
220                             head_tree,
221                             next_tree, base_tree, &result);
222
223         if (active_cache_changed &&
224             (write_cache(index_fd, active_cache, active_nr) ||
225              commit_locked_index(&index_lock)))
226                 /* TRANSLATORS: %s will be "revert" or "cherry-pick" */
227                 die(_("%s: Unable to write new index file"), action_name(opts));
228         rollback_lock_file(&index_lock);
229
230         if (!clean) {
231                 int i;
232                 strbuf_addstr(msgbuf, "\nConflicts:\n\n");
233                 for (i = 0; i < active_nr;) {
234                         struct cache_entry *ce = active_cache[i++];
235                         if (ce_stage(ce)) {
236                                 strbuf_addch(msgbuf, '\t');
237                                 strbuf_addstr(msgbuf, ce->name);
238                                 strbuf_addch(msgbuf, '\n');
239                                 while (i < active_nr && !strcmp(ce->name,
240                                                 active_cache[i]->name))
241                                         i++;
242                         }
243                 }
244         }
245
246         return !clean;
247 }
248
249 /*
250  * If we are cherry-pick, and if the merge did not result in
251  * hand-editing, we will hit this commit and inherit the original
252  * author date and name.
253  * If we are revert, or if our cherry-pick results in a hand merge,
254  * we had better say that the current user is responsible for that.
255  */
256 static int run_git_commit(const char *defmsg, struct replay_opts *opts)
257 {
258         /* 6 is max possible length of our args array including NULL */
259         const char *args[6];
260         int i = 0;
261
262         args[i++] = "commit";
263         args[i++] = "-n";
264         if (opts->signoff)
265                 args[i++] = "-s";
266         if (!opts->edit) {
267                 args[i++] = "-F";
268                 args[i++] = defmsg;
269         }
270         args[i] = NULL;
271
272         return run_command_v_opt(args, RUN_GIT_CMD);
273 }
274
275 static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
276 {
277         unsigned char head[20];
278         struct commit *base, *next, *parent;
279         const char *base_label, *next_label;
280         struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
281         char *defmsg = NULL;
282         struct strbuf msgbuf = STRBUF_INIT;
283         int res;
284
285         if (opts->no_commit) {
286                 /*
287                  * We do not intend to commit immediately.  We just want to
288                  * merge the differences in, so let's compute the tree
289                  * that represents the "current" state for merge-recursive
290                  * to work on.
291                  */
292                 if (write_cache_as_tree(head, 0, NULL))
293                         die (_("Your index file is unmerged."));
294         } else {
295                 if (get_sha1("HEAD", head))
296                         return error(_("You do not have a valid HEAD"));
297                 if (index_differs_from("HEAD", 0))
298                         return error_dirty_index(opts);
299         }
300         discard_cache();
301
302         if (!commit->parents) {
303                 parent = NULL;
304         }
305         else if (commit->parents->next) {
306                 /* Reverting or cherry-picking a merge commit */
307                 int cnt;
308                 struct commit_list *p;
309
310                 if (!opts->mainline)
311                         return error(_("Commit %s is a merge but no -m option was given."),
312                                 sha1_to_hex(commit->object.sha1));
313
314                 for (cnt = 1, p = commit->parents;
315                      cnt != opts->mainline && p;
316                      cnt++)
317                         p = p->next;
318                 if (cnt != opts->mainline || !p)
319                         return error(_("Commit %s does not have parent %d"),
320                                 sha1_to_hex(commit->object.sha1), opts->mainline);
321                 parent = p->item;
322         } else if (0 < opts->mainline)
323                 return error(_("Mainline was specified but commit %s is not a merge."),
324                         sha1_to_hex(commit->object.sha1));
325         else
326                 parent = commit->parents->item;
327
328         if (opts->allow_ff && parent && !hashcmp(parent->object.sha1, head))
329                 return fast_forward_to(commit->object.sha1, head);
330
331         if (parent && parse_commit(parent) < 0)
332                 /* TRANSLATORS: The first %s will be "revert" or
333                    "cherry-pick", the second %s a SHA1 */
334                 return error(_("%s: cannot parse parent commit %s"),
335                         action_name(opts), sha1_to_hex(parent->object.sha1));
336
337         if (get_message(commit, &msg) != 0)
338                 return error(_("Cannot get commit message for %s"),
339                         sha1_to_hex(commit->object.sha1));
340
341         /*
342          * "commit" is an existing commit.  We would want to apply
343          * the difference it introduces since its first parent "prev"
344          * on top of the current HEAD if we are cherry-pick.  Or the
345          * reverse of it if we are revert.
346          */
347
348         defmsg = git_pathdup("MERGE_MSG");
349
350         if (opts->action == REPLAY_REVERT) {
351                 base = commit;
352                 base_label = msg.label;
353                 next = parent;
354                 next_label = msg.parent_label;
355                 strbuf_addstr(&msgbuf, "Revert \"");
356                 strbuf_addstr(&msgbuf, msg.subject);
357                 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
358                 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
359
360                 if (commit->parents && commit->parents->next) {
361                         strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
362                         strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
363                 }
364                 strbuf_addstr(&msgbuf, ".\n");
365         } else {
366                 const char *p;
367
368                 base = parent;
369                 base_label = msg.parent_label;
370                 next = commit;
371                 next_label = msg.label;
372
373                 /*
374                  * Append the commit log message to msgbuf; it starts
375                  * after the tree, parent, author, committer
376                  * information followed by "\n\n".
377                  */
378                 p = strstr(msg.message, "\n\n");
379                 if (p) {
380                         p += 2;
381                         strbuf_addstr(&msgbuf, p);
382                 }
383
384                 if (opts->record_origin) {
385                         strbuf_addstr(&msgbuf, "(cherry picked from commit ");
386                         strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
387                         strbuf_addstr(&msgbuf, ")\n");
388                 }
389         }
390
391         if (!opts->strategy || !strcmp(opts->strategy, "recursive") || opts->action == REPLAY_REVERT) {
392                 res = do_recursive_merge(base, next, base_label, next_label,
393                                          head, &msgbuf, opts);
394                 write_message(&msgbuf, defmsg);
395         } else {
396                 struct commit_list *common = NULL;
397                 struct commit_list *remotes = NULL;
398
399                 write_message(&msgbuf, defmsg);
400
401                 commit_list_insert(base, &common);
402                 commit_list_insert(next, &remotes);
403                 res = try_merge_command(opts->strategy, opts->xopts_nr, opts->xopts,
404                                         common, sha1_to_hex(head), remotes);
405                 free_commit_list(common);
406                 free_commit_list(remotes);
407         }
408
409         /*
410          * If the merge was clean or if it failed due to conflict, we write
411          * CHERRY_PICK_HEAD for the subsequent invocation of commit to use.
412          * However, if the merge did not even start, then we don't want to
413          * write it at all.
414          */
415         if (opts->action == REPLAY_PICK && !opts->no_commit && (res == 0 || res == 1))
416                 write_cherry_pick_head(commit, "CHERRY_PICK_HEAD");
417         if (opts->action == REPLAY_REVERT && ((opts->no_commit && res == 0) || res == 1))
418                 write_cherry_pick_head(commit, "REVERT_HEAD");
419
420         if (res) {
421                 error(opts->action == REPLAY_REVERT
422                       ? _("could not revert %s... %s")
423                       : _("could not apply %s... %s"),
424                       find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV),
425                       msg.subject);
426                 print_advice(res == 1);
427                 rerere(opts->allow_rerere_auto);
428         } else {
429                 if (!opts->no_commit)
430                         res = run_git_commit(defmsg, opts);
431         }
432
433         free_message(&msg);
434         free(defmsg);
435
436         return res;
437 }
438
439 static void prepare_revs(struct replay_opts *opts)
440 {
441         if (opts->action != REPLAY_REVERT)
442                 opts->revs->reverse ^= 1;
443
444         if (prepare_revision_walk(opts->revs))
445                 die(_("revision walk setup failed"));
446
447         if (!opts->revs->commits)
448                 die(_("empty commit set passed"));
449 }
450
451 static void read_and_refresh_cache(struct replay_opts *opts)
452 {
453         static struct lock_file index_lock;
454         int index_fd = hold_locked_index(&index_lock, 0);
455         if (read_index_preload(&the_index, NULL) < 0)
456                 die(_("git %s: failed to read the index"), action_name(opts));
457         refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
458         if (the_index.cache_changed) {
459                 if (write_index(&the_index, index_fd) ||
460                     commit_locked_index(&index_lock))
461                         die(_("git %s: failed to refresh the index"), action_name(opts));
462         }
463         rollback_lock_file(&index_lock);
464 }
465
466 /*
467  * Append a commit to the end of the commit_list.
468  *
469  * next starts by pointing to the variable that holds the head of an
470  * empty commit_list, and is updated to point to the "next" field of
471  * the last item on the list as new commits are appended.
472  *
473  * Usage example:
474  *
475  *     struct commit_list *list;
476  *     struct commit_list **next = &list;
477  *
478  *     next = commit_list_append(c1, next);
479  *     next = commit_list_append(c2, next);
480  *     assert(commit_list_count(list) == 2);
481  *     return list;
482  */
483 static struct commit_list **commit_list_append(struct commit *commit,
484                                                struct commit_list **next)
485 {
486         struct commit_list *new = xmalloc(sizeof(struct commit_list));
487         new->item = commit;
488         *next = new;
489         new->next = NULL;
490         return &new->next;
491 }
492
493 static int format_todo(struct strbuf *buf, struct commit_list *todo_list,
494                 struct replay_opts *opts)
495 {
496         struct commit_list *cur = NULL;
497         const char *sha1_abbrev = NULL;
498         const char *action_str = opts->action == REPLAY_REVERT ? "revert" : "pick";
499         const char *subject;
500         int subject_len;
501
502         for (cur = todo_list; cur; cur = cur->next) {
503                 sha1_abbrev = find_unique_abbrev(cur->item->object.sha1, DEFAULT_ABBREV);
504                 subject_len = find_commit_subject(cur->item->buffer, &subject);
505                 strbuf_addf(buf, "%s %s %.*s\n", action_str, sha1_abbrev,
506                         subject_len, subject);
507         }
508         return 0;
509 }
510
511 static struct commit *parse_insn_line(char *bol, char *eol, struct replay_opts *opts)
512 {
513         unsigned char commit_sha1[20];
514         enum replay_action action;
515         char *end_of_object_name;
516         int saved, status, padding;
517
518         if (!prefixcmp(bol, "pick")) {
519                 action = REPLAY_PICK;
520                 bol += strlen("pick");
521         } else if (!prefixcmp(bol, "revert")) {
522                 action = REPLAY_REVERT;
523                 bol += strlen("revert");
524         } else
525                 return NULL;
526
527         /* Eat up extra spaces/ tabs before object name */
528         padding = strspn(bol, " \t");
529         if (!padding)
530                 return NULL;
531         bol += padding;
532
533         end_of_object_name = bol + strcspn(bol, " \t\n");
534         saved = *end_of_object_name;
535         *end_of_object_name = '\0';
536         status = get_sha1(bol, commit_sha1);
537         *end_of_object_name = saved;
538
539         /*
540          * Verify that the action matches up with the one in
541          * opts; we don't support arbitrary instructions
542          */
543         if (action != opts->action) {
544                 const char *action_str;
545                 action_str = action == REPLAY_REVERT ? "revert" : "cherry-pick";
546                 error(_("Cannot %s during a %s"), action_str, action_name(opts));
547                 return NULL;
548         }
549
550         if (status < 0)
551                 return NULL;
552
553         return lookup_commit_reference(commit_sha1);
554 }
555
556 static int parse_insn_buffer(char *buf, struct commit_list **todo_list,
557                         struct replay_opts *opts)
558 {
559         struct commit_list **next = todo_list;
560         struct commit *commit;
561         char *p = buf;
562         int i;
563
564         for (i = 1; *p; i++) {
565                 char *eol = strchrnul(p, '\n');
566                 commit = parse_insn_line(p, eol, opts);
567                 if (!commit)
568                         return error(_("Could not parse line %d."), i);
569                 next = commit_list_append(commit, next);
570                 p = *eol ? eol + 1 : eol;
571         }
572         if (!*todo_list)
573                 return error(_("No commits parsed."));
574         return 0;
575 }
576
577 static void read_populate_todo(struct commit_list **todo_list,
578                         struct replay_opts *opts)
579 {
580         const char *todo_file = git_path(SEQ_TODO_FILE);
581         struct strbuf buf = STRBUF_INIT;
582         int fd, res;
583
584         fd = open(todo_file, O_RDONLY);
585         if (fd < 0)
586                 die_errno(_("Could not open %s"), todo_file);
587         if (strbuf_read(&buf, fd, 0) < 0) {
588                 close(fd);
589                 strbuf_release(&buf);
590                 die(_("Could not read %s."), todo_file);
591         }
592         close(fd);
593
594         res = parse_insn_buffer(buf.buf, todo_list, opts);
595         strbuf_release(&buf);
596         if (res)
597                 die(_("Unusable instruction sheet: %s"), todo_file);
598 }
599
600 static int populate_opts_cb(const char *key, const char *value, void *data)
601 {
602         struct replay_opts *opts = data;
603         int error_flag = 1;
604
605         if (!value)
606                 error_flag = 0;
607         else if (!strcmp(key, "options.no-commit"))
608                 opts->no_commit = git_config_bool_or_int(key, value, &error_flag);
609         else if (!strcmp(key, "options.edit"))
610                 opts->edit = git_config_bool_or_int(key, value, &error_flag);
611         else if (!strcmp(key, "options.signoff"))
612                 opts->signoff = git_config_bool_or_int(key, value, &error_flag);
613         else if (!strcmp(key, "options.record-origin"))
614                 opts->record_origin = git_config_bool_or_int(key, value, &error_flag);
615         else if (!strcmp(key, "options.allow-ff"))
616                 opts->allow_ff = git_config_bool_or_int(key, value, &error_flag);
617         else if (!strcmp(key, "options.mainline"))
618                 opts->mainline = git_config_int(key, value);
619         else if (!strcmp(key, "options.strategy"))
620                 git_config_string(&opts->strategy, key, value);
621         else if (!strcmp(key, "options.strategy-option")) {
622                 ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
623                 opts->xopts[opts->xopts_nr++] = xstrdup(value);
624         } else
625                 return error(_("Invalid key: %s"), key);
626
627         if (!error_flag)
628                 return error(_("Invalid value for %s: %s"), key, value);
629
630         return 0;
631 }
632
633 static void read_populate_opts(struct replay_opts **opts_ptr)
634 {
635         const char *opts_file = git_path(SEQ_OPTS_FILE);
636
637         if (!file_exists(opts_file))
638                 return;
639         if (git_config_from_file(populate_opts_cb, opts_file, *opts_ptr) < 0)
640                 die(_("Malformed options sheet: %s"), opts_file);
641 }
642
643 static void walk_revs_populate_todo(struct commit_list **todo_list,
644                                 struct replay_opts *opts)
645 {
646         struct commit *commit;
647         struct commit_list **next;
648
649         prepare_revs(opts);
650
651         next = todo_list;
652         while ((commit = get_revision(opts->revs)))
653                 next = commit_list_append(commit, next);
654 }
655
656 static int create_seq_dir(void)
657 {
658         const char *seq_dir = git_path(SEQ_DIR);
659
660         if (file_exists(seq_dir)) {
661                 error(_("a cherry-pick or revert is already in progress"));
662                 advise(_("try \"git cherry-pick (--continue | --quit | --abort)\""));
663                 return -1;
664         }
665         else if (mkdir(seq_dir, 0777) < 0)
666                 die_errno(_("Could not create sequencer directory %s"), seq_dir);
667         return 0;
668 }
669
670 static void save_head(const char *head)
671 {
672         const char *head_file = git_path(SEQ_HEAD_FILE);
673         static struct lock_file head_lock;
674         struct strbuf buf = STRBUF_INIT;
675         int fd;
676
677         fd = hold_lock_file_for_update(&head_lock, head_file, LOCK_DIE_ON_ERROR);
678         strbuf_addf(&buf, "%s\n", head);
679         if (write_in_full(fd, buf.buf, buf.len) < 0)
680                 die_errno(_("Could not write to %s"), head_file);
681         if (commit_lock_file(&head_lock) < 0)
682                 die(_("Error wrapping up %s."), head_file);
683 }
684
685 static int reset_for_rollback(const unsigned char *sha1)
686 {
687         const char *argv[4];    /* reset --merge <arg> + NULL */
688         argv[0] = "reset";
689         argv[1] = "--merge";
690         argv[2] = sha1_to_hex(sha1);
691         argv[3] = NULL;
692         return run_command_v_opt(argv, RUN_GIT_CMD);
693 }
694
695 static int rollback_single_pick(void)
696 {
697         unsigned char head_sha1[20];
698
699         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
700             !file_exists(git_path("REVERT_HEAD")))
701                 return error(_("no cherry-pick or revert in progress"));
702         if (read_ref_full("HEAD", head_sha1, 0, NULL))
703                 return error(_("cannot resolve HEAD"));
704         if (is_null_sha1(head_sha1))
705                 return error(_("cannot abort from a branch yet to be born"));
706         return reset_for_rollback(head_sha1);
707 }
708
709 static int sequencer_rollback(struct replay_opts *opts)
710 {
711         const char *filename;
712         FILE *f;
713         unsigned char sha1[20];
714         struct strbuf buf = STRBUF_INIT;
715
716         filename = git_path(SEQ_HEAD_FILE);
717         f = fopen(filename, "r");
718         if (!f && errno == ENOENT) {
719                 /*
720                  * There is no multiple-cherry-pick in progress.
721                  * If CHERRY_PICK_HEAD or REVERT_HEAD indicates
722                  * a single-cherry-pick in progress, abort that.
723                  */
724                 return rollback_single_pick();
725         }
726         if (!f)
727                 return error(_("cannot open %s: %s"), filename,
728                                                 strerror(errno));
729         if (strbuf_getline(&buf, f, '\n')) {
730                 error(_("cannot read %s: %s"), filename, ferror(f) ?
731                         strerror(errno) : _("unexpected end of file"));
732                 fclose(f);
733                 goto fail;
734         }
735         fclose(f);
736         if (get_sha1_hex(buf.buf, sha1) || buf.buf[40] != '\0') {
737                 error(_("stored pre-cherry-pick HEAD file '%s' is corrupt"),
738                         filename);
739                 goto fail;
740         }
741         if (reset_for_rollback(sha1))
742                 goto fail;
743         remove_sequencer_state();
744         strbuf_release(&buf);
745         return 0;
746 fail:
747         strbuf_release(&buf);
748         return -1;
749 }
750
751 static void save_todo(struct commit_list *todo_list, struct replay_opts *opts)
752 {
753         const char *todo_file = git_path(SEQ_TODO_FILE);
754         static struct lock_file todo_lock;
755         struct strbuf buf = STRBUF_INIT;
756         int fd;
757
758         fd = hold_lock_file_for_update(&todo_lock, todo_file, LOCK_DIE_ON_ERROR);
759         if (format_todo(&buf, todo_list, opts) < 0)
760                 die(_("Could not format %s."), todo_file);
761         if (write_in_full(fd, buf.buf, buf.len) < 0) {
762                 strbuf_release(&buf);
763                 die_errno(_("Could not write to %s"), todo_file);
764         }
765         if (commit_lock_file(&todo_lock) < 0) {
766                 strbuf_release(&buf);
767                 die(_("Error wrapping up %s."), todo_file);
768         }
769         strbuf_release(&buf);
770 }
771
772 static void save_opts(struct replay_opts *opts)
773 {
774         const char *opts_file = git_path(SEQ_OPTS_FILE);
775
776         if (opts->no_commit)
777                 git_config_set_in_file(opts_file, "options.no-commit", "true");
778         if (opts->edit)
779                 git_config_set_in_file(opts_file, "options.edit", "true");
780         if (opts->signoff)
781                 git_config_set_in_file(opts_file, "options.signoff", "true");
782         if (opts->record_origin)
783                 git_config_set_in_file(opts_file, "options.record-origin", "true");
784         if (opts->allow_ff)
785                 git_config_set_in_file(opts_file, "options.allow-ff", "true");
786         if (opts->mainline) {
787                 struct strbuf buf = STRBUF_INIT;
788                 strbuf_addf(&buf, "%d", opts->mainline);
789                 git_config_set_in_file(opts_file, "options.mainline", buf.buf);
790                 strbuf_release(&buf);
791         }
792         if (opts->strategy)
793                 git_config_set_in_file(opts_file, "options.strategy", opts->strategy);
794         if (opts->xopts) {
795                 int i;
796                 for (i = 0; i < opts->xopts_nr; i++)
797                         git_config_set_multivar_in_file(opts_file,
798                                                         "options.strategy-option",
799                                                         opts->xopts[i], "^$", 0);
800         }
801 }
802
803 static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
804 {
805         struct commit_list *cur;
806         int res;
807
808         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
809         if (opts->allow_ff)
810                 assert(!(opts->signoff || opts->no_commit ||
811                                 opts->record_origin || opts->edit));
812         read_and_refresh_cache(opts);
813
814         for (cur = todo_list; cur; cur = cur->next) {
815                 save_todo(cur, opts);
816                 res = do_pick_commit(cur->item, opts);
817                 if (res)
818                         return res;
819         }
820
821         /*
822          * Sequence of picks finished successfully; cleanup by
823          * removing the .git/sequencer directory
824          */
825         remove_sequencer_state();
826         return 0;
827 }
828
829 static int continue_single_pick(void)
830 {
831         const char *argv[] = { "commit", NULL };
832
833         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
834             !file_exists(git_path("REVERT_HEAD")))
835                 return error(_("no cherry-pick or revert in progress"));
836         return run_command_v_opt(argv, RUN_GIT_CMD);
837 }
838
839 static int sequencer_continue(struct replay_opts *opts)
840 {
841         struct commit_list *todo_list = NULL;
842
843         if (!file_exists(git_path(SEQ_TODO_FILE)))
844                 return continue_single_pick();
845         read_populate_opts(&opts);
846         read_populate_todo(&todo_list, opts);
847
848         /* Verify that the conflict has been resolved */
849         if (file_exists(git_path("CHERRY_PICK_HEAD")) ||
850             file_exists(git_path("REVERT_HEAD"))) {
851                 int ret = continue_single_pick();
852                 if (ret)
853                         return ret;
854         }
855         if (index_differs_from("HEAD", 0))
856                 return error_dirty_index(opts);
857         todo_list = todo_list->next;
858         return pick_commits(todo_list, opts);
859 }
860
861 static int single_pick(struct commit *cmit, struct replay_opts *opts)
862 {
863         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
864         return do_pick_commit(cmit, opts);
865 }
866
867 int sequencer_pick_revisions(struct replay_opts *opts)
868 {
869         struct commit_list *todo_list = NULL;
870         unsigned char sha1[20];
871
872         if (opts->subcommand == REPLAY_NONE)
873                 assert(opts->revs);
874
875         read_and_refresh_cache(opts);
876
877         /*
878          * Decide what to do depending on the arguments; a fresh
879          * cherry-pick should be handled differently from an existing
880          * one that is being continued
881          */
882         if (opts->subcommand == REPLAY_REMOVE_STATE) {
883                 remove_sequencer_state();
884                 return 0;
885         }
886         if (opts->subcommand == REPLAY_ROLLBACK)
887                 return sequencer_rollback(opts);
888         if (opts->subcommand == REPLAY_CONTINUE)
889                 return sequencer_continue(opts);
890
891         /*
892          * If we were called as "git cherry-pick <commit>", just
893          * cherry-pick/revert it, set CHERRY_PICK_HEAD /
894          * REVERT_HEAD, and don't touch the sequencer state.
895          * This means it is possible to cherry-pick in the middle
896          * of a cherry-pick sequence.
897          */
898         if (opts->revs->cmdline.nr == 1 &&
899             opts->revs->cmdline.rev->whence == REV_CMD_REV &&
900             opts->revs->no_walk &&
901             !opts->revs->cmdline.rev->flags) {
902                 struct commit *cmit;
903                 if (prepare_revision_walk(opts->revs))
904                         die(_("revision walk setup failed"));
905                 cmit = get_revision(opts->revs);
906                 if (!cmit || get_revision(opts->revs))
907                         die("BUG: expected exactly one commit from walk");
908                 return single_pick(cmit, opts);
909         }
910
911         /*
912          * Start a new cherry-pick/ revert sequence; but
913          * first, make sure that an existing one isn't in
914          * progress
915          */
916
917         walk_revs_populate_todo(&todo_list, opts);
918         if (create_seq_dir() < 0)
919                 return -1;
920         if (get_sha1("HEAD", sha1)) {
921                 if (opts->action == REPLAY_REVERT)
922                         return error(_("Can't revert as initial commit"));
923                 return error(_("Can't cherry-pick into empty head"));
924         }
925         save_head(sha1_to_hex(sha1));
926         save_opts(opts);
927         return pick_commits(todo_list, opts);
928 }