Merge branch 'po/doc-assume-unchanged'
[git] / sequencer.c
1 #include "cache.h"
2 #include "lockfile.h"
3 #include "sequencer.h"
4 #include "dir.h"
5 #include "object.h"
6 #include "commit.h"
7 #include "tag.h"
8 #include "run-command.h"
9 #include "exec_cmd.h"
10 #include "utf8.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 #include "argv-array.h"
18
19 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
20
21 const char sign_off_header[] = "Signed-off-by: ";
22 static const char cherry_picked_prefix[] = "(cherry picked from commit ";
23
24 static int is_rfc2822_line(const char *buf, int len)
25 {
26         int i;
27
28         for (i = 0; i < len; i++) {
29                 int ch = buf[i];
30                 if (ch == ':')
31                         return 1;
32                 if (!isalnum(ch) && ch != '-')
33                         break;
34         }
35
36         return 0;
37 }
38
39 static int is_cherry_picked_from_line(const char *buf, int len)
40 {
41         /*
42          * We only care that it looks roughly like (cherry picked from ...)
43          */
44         return len > strlen(cherry_picked_prefix) + 1 &&
45                 starts_with(buf, cherry_picked_prefix) && buf[len - 1] == ')';
46 }
47
48 /*
49  * Returns 0 for non-conforming footer
50  * Returns 1 for conforming footer
51  * Returns 2 when sob exists within conforming footer
52  * Returns 3 when sob exists within conforming footer as last entry
53  */
54 static int has_conforming_footer(struct strbuf *sb, struct strbuf *sob,
55         int ignore_footer)
56 {
57         char prev;
58         int i, k;
59         int len = sb->len - ignore_footer;
60         const char *buf = sb->buf;
61         int found_sob = 0;
62
63         /* footer must end with newline */
64         if (!len || buf[len - 1] != '\n')
65                 return 0;
66
67         prev = '\0';
68         for (i = len - 1; i > 0; i--) {
69                 char ch = buf[i];
70                 if (prev == '\n' && ch == '\n') /* paragraph break */
71                         break;
72                 prev = ch;
73         }
74
75         /* require at least one blank line */
76         if (prev != '\n' || buf[i] != '\n')
77                 return 0;
78
79         /* advance to start of last paragraph */
80         while (i < len - 1 && buf[i] == '\n')
81                 i++;
82
83         for (; i < len; i = k) {
84                 int found_rfc2822;
85
86                 for (k = i; k < len && buf[k] != '\n'; k++)
87                         ; /* do nothing */
88                 k++;
89
90                 found_rfc2822 = is_rfc2822_line(buf + i, k - i - 1);
91                 if (found_rfc2822 && sob &&
92                     !strncmp(buf + i, sob->buf, sob->len))
93                         found_sob = k;
94
95                 if (!(found_rfc2822 ||
96                       is_cherry_picked_from_line(buf + i, k - i - 1)))
97                         return 0;
98         }
99         if (found_sob == i)
100                 return 3;
101         if (found_sob)
102                 return 2;
103         return 1;
104 }
105
106 static void remove_sequencer_state(void)
107 {
108         struct strbuf seq_dir = STRBUF_INIT;
109
110         strbuf_addf(&seq_dir, "%s", git_path(SEQ_DIR));
111         remove_dir_recursively(&seq_dir, 0);
112         strbuf_release(&seq_dir);
113 }
114
115 static const char *action_name(const struct replay_opts *opts)
116 {
117         return opts->action == REPLAY_REVERT ? "revert" : "cherry-pick";
118 }
119
120 struct commit_message {
121         char *parent_label;
122         const char *label;
123         const char *subject;
124         const char *message;
125 };
126
127 static int get_message(struct commit *commit, struct commit_message *out)
128 {
129         const char *abbrev, *subject;
130         int abbrev_len, subject_len;
131         char *q;
132
133         if (!git_commit_encoding)
134                 git_commit_encoding = "UTF-8";
135
136         out->message = logmsg_reencode(commit, NULL, git_commit_encoding);
137         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
138         abbrev_len = strlen(abbrev);
139
140         subject_len = find_commit_subject(out->message, &subject);
141
142         out->parent_label = xmalloc(strlen("parent of ") + abbrev_len +
143                               strlen("... ") + subject_len + 1);
144         q = out->parent_label;
145         q = mempcpy(q, "parent of ", strlen("parent of "));
146         out->label = q;
147         q = mempcpy(q, abbrev, abbrev_len);
148         q = mempcpy(q, "... ", strlen("... "));
149         out->subject = q;
150         q = mempcpy(q, subject, subject_len);
151         *q = '\0';
152         return 0;
153 }
154
155 static void free_message(struct commit *commit, struct commit_message *msg)
156 {
157         free(msg->parent_label);
158         unuse_commit_buffer(commit, msg->message);
159 }
160
161 static void write_cherry_pick_head(struct commit *commit, const char *pseudoref)
162 {
163         const char *filename;
164         int fd;
165         struct strbuf buf = STRBUF_INIT;
166
167         strbuf_addf(&buf, "%s\n", sha1_to_hex(commit->object.sha1));
168
169         filename = git_path("%s", pseudoref);
170         fd = open(filename, O_WRONLY | O_CREAT, 0666);
171         if (fd < 0)
172                 die_errno(_("Could not open '%s' for writing"), filename);
173         if (write_in_full(fd, buf.buf, buf.len) != buf.len || close(fd))
174                 die_errno(_("Could not write to '%s'"), filename);
175         strbuf_release(&buf);
176 }
177
178 static void print_advice(int show_hint, struct replay_opts *opts)
179 {
180         char *msg = getenv("GIT_CHERRY_PICK_HELP");
181
182         if (msg) {
183                 fprintf(stderr, "%s\n", msg);
184                 /*
185                  * A conflict has occurred but the porcelain
186                  * (typically rebase --interactive) wants to take care
187                  * of the commit itself so remove CHERRY_PICK_HEAD
188                  */
189                 unlink(git_path("CHERRY_PICK_HEAD"));
190                 return;
191         }
192
193         if (show_hint) {
194                 if (opts->no_commit)
195                         advise(_("after resolving the conflicts, mark the corrected paths\n"
196                                  "with 'git add <paths>' or 'git rm <paths>'"));
197                 else
198                         advise(_("after resolving the conflicts, mark the corrected paths\n"
199                                  "with 'git add <paths>' or 'git rm <paths>'\n"
200                                  "and commit the result with 'git commit'"));
201         }
202 }
203
204 static void write_message(struct strbuf *msgbuf, const char *filename)
205 {
206         static struct lock_file msg_file;
207
208         int msg_fd = hold_lock_file_for_update(&msg_file, filename,
209                                                LOCK_DIE_ON_ERROR);
210         if (write_in_full(msg_fd, msgbuf->buf, msgbuf->len) < 0)
211                 die_errno(_("Could not write to %s"), filename);
212         strbuf_release(msgbuf);
213         if (commit_lock_file(&msg_file) < 0)
214                 die(_("Error wrapping up %s"), filename);
215 }
216
217 static struct tree *empty_tree(void)
218 {
219         return lookup_tree(EMPTY_TREE_SHA1_BIN);
220 }
221
222 static int error_dirty_index(struct replay_opts *opts)
223 {
224         if (read_cache_unmerged())
225                 return error_resolve_conflict(action_name(opts));
226
227         /* Different translation strings for cherry-pick and revert */
228         if (opts->action == REPLAY_PICK)
229                 error(_("Your local changes would be overwritten by cherry-pick."));
230         else
231                 error(_("Your local changes would be overwritten by revert."));
232
233         if (advice_commit_before_merge)
234                 advise(_("Commit your changes or stash them to proceed."));
235         return -1;
236 }
237
238 static int fast_forward_to(const unsigned char *to, const unsigned char *from,
239                         int unborn, struct replay_opts *opts)
240 {
241         struct ref_transaction *transaction;
242         struct strbuf sb = STRBUF_INIT;
243         struct strbuf err = STRBUF_INIT;
244
245         read_cache();
246         if (checkout_fast_forward(from, to, 1))
247                 exit(128); /* the callee should have complained already */
248
249         strbuf_addf(&sb, "%s: fast-forward", action_name(opts));
250
251         transaction = ref_transaction_begin(&err);
252         if (!transaction ||
253             ref_transaction_update(transaction, "HEAD",
254                                    to, unborn ? null_sha1 : from,
255                                    0, 1, sb.buf, &err) ||
256             ref_transaction_commit(transaction, &err)) {
257                 ref_transaction_free(transaction);
258                 error("%s", err.buf);
259                 strbuf_release(&sb);
260                 strbuf_release(&err);
261                 return -1;
262         }
263
264         strbuf_release(&sb);
265         strbuf_release(&err);
266         ref_transaction_free(transaction);
267         return 0;
268 }
269
270 void append_conflicts_hint(struct strbuf *msgbuf)
271 {
272         int i;
273
274         strbuf_addch(msgbuf, '\n');
275         strbuf_commented_addf(msgbuf, "Conflicts:\n");
276         for (i = 0; i < active_nr;) {
277                 const struct cache_entry *ce = active_cache[i++];
278                 if (ce_stage(ce)) {
279                         strbuf_commented_addf(msgbuf, "\t%s\n", ce->name);
280                         while (i < active_nr && !strcmp(ce->name,
281                                                         active_cache[i]->name))
282                                 i++;
283                 }
284         }
285 }
286
287 static int do_recursive_merge(struct commit *base, struct commit *next,
288                               const char *base_label, const char *next_label,
289                               unsigned char *head, struct strbuf *msgbuf,
290                               struct replay_opts *opts)
291 {
292         struct merge_options o;
293         struct tree *result, *next_tree, *base_tree, *head_tree;
294         int clean;
295         const char **xopt;
296         static struct lock_file index_lock;
297
298         hold_locked_index(&index_lock, 1);
299
300         read_cache();
301
302         init_merge_options(&o);
303         o.ancestor = base ? base_label : "(empty tree)";
304         o.branch1 = "HEAD";
305         o.branch2 = next ? next_label : "(empty tree)";
306
307         head_tree = parse_tree_indirect(head);
308         next_tree = next ? next->tree : empty_tree();
309         base_tree = base ? base->tree : empty_tree();
310
311         for (xopt = opts->xopts; xopt != opts->xopts + opts->xopts_nr; xopt++)
312                 parse_merge_opt(&o, *xopt);
313
314         clean = merge_trees(&o,
315                             head_tree,
316                             next_tree, base_tree, &result);
317
318         if (active_cache_changed &&
319             write_locked_index(&the_index, &index_lock, COMMIT_LOCK))
320                 /* TRANSLATORS: %s will be "revert" or "cherry-pick" */
321                 die(_("%s: Unable to write new index file"), action_name(opts));
322         rollback_lock_file(&index_lock);
323
324         if (opts->signoff)
325                 append_signoff(msgbuf, 0, 0);
326
327         if (!clean)
328                 append_conflicts_hint(msgbuf);
329
330         return !clean;
331 }
332
333 static int is_index_unchanged(void)
334 {
335         unsigned char head_sha1[20];
336         struct commit *head_commit;
337
338         if (!resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, head_sha1, NULL))
339                 return error(_("Could not resolve HEAD commit\n"));
340
341         head_commit = lookup_commit(head_sha1);
342
343         /*
344          * If head_commit is NULL, check_commit, called from
345          * lookup_commit, would have indicated that head_commit is not
346          * a commit object already.  parse_commit() will return failure
347          * without further complaints in such a case.  Otherwise, if
348          * the commit is invalid, parse_commit() will complain.  So
349          * there is nothing for us to say here.  Just return failure.
350          */
351         if (parse_commit(head_commit))
352                 return -1;
353
354         if (!active_cache_tree)
355                 active_cache_tree = cache_tree();
356
357         if (!cache_tree_fully_valid(active_cache_tree))
358                 if (cache_tree_update(&the_index, 0))
359                         return error(_("Unable to update cache tree\n"));
360
361         return !hashcmp(active_cache_tree->sha1, head_commit->tree->object.sha1);
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, struct replay_opts *opts,
372                           int allow_empty)
373 {
374         struct argv_array array;
375         int rc;
376
377         argv_array_init(&array);
378         argv_array_push(&array, "commit");
379         argv_array_push(&array, "-n");
380
381         if (opts->gpg_sign)
382                 argv_array_pushf(&array, "-S%s", opts->gpg_sign);
383         if (opts->signoff)
384                 argv_array_push(&array, "-s");
385         if (!opts->edit) {
386                 argv_array_push(&array, "-F");
387                 argv_array_push(&array, defmsg);
388         }
389
390         if (allow_empty)
391                 argv_array_push(&array, "--allow-empty");
392
393         if (opts->allow_empty_message)
394                 argv_array_push(&array, "--allow-empty-message");
395
396         rc = run_command_v_opt(array.argv, RUN_GIT_CMD);
397         argv_array_clear(&array);
398         return rc;
399 }
400
401 static int is_original_commit_empty(struct commit *commit)
402 {
403         const unsigned char *ptree_sha1;
404
405         if (parse_commit(commit))
406                 return error(_("Could not parse commit %s\n"),
407                              sha1_to_hex(commit->object.sha1));
408         if (commit->parents) {
409                 struct commit *parent = commit->parents->item;
410                 if (parse_commit(parent))
411                         return error(_("Could not parse parent commit %s\n"),
412                                 sha1_to_hex(parent->object.sha1));
413                 ptree_sha1 = parent->tree->object.sha1;
414         } else {
415                 ptree_sha1 = EMPTY_TREE_SHA1_BIN; /* commit is root */
416         }
417
418         return !hashcmp(ptree_sha1, commit->tree->object.sha1);
419 }
420
421 /*
422  * Do we run "git commit" with "--allow-empty"?
423  */
424 static int allow_empty(struct replay_opts *opts, struct commit *commit)
425 {
426         int index_unchanged, empty_commit;
427
428         /*
429          * Three cases:
430          *
431          * (1) we do not allow empty at all and error out.
432          *
433          * (2) we allow ones that were initially empty, but
434          * forbid the ones that become empty;
435          *
436          * (3) we allow both.
437          */
438         if (!opts->allow_empty)
439                 return 0; /* let "git commit" barf as necessary */
440
441         index_unchanged = is_index_unchanged();
442         if (index_unchanged < 0)
443                 return index_unchanged;
444         if (!index_unchanged)
445                 return 0; /* we do not have to say --allow-empty */
446
447         if (opts->keep_redundant_commits)
448                 return 1;
449
450         empty_commit = is_original_commit_empty(commit);
451         if (empty_commit < 0)
452                 return empty_commit;
453         if (!empty_commit)
454                 return 0;
455         else
456                 return 1;
457 }
458
459 static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
460 {
461         unsigned char head[20];
462         struct commit *base, *next, *parent;
463         const char *base_label, *next_label;
464         struct commit_message msg = { NULL, NULL, NULL, NULL };
465         char *defmsg = NULL;
466         struct strbuf msgbuf = STRBUF_INIT;
467         int res, unborn = 0, allow;
468
469         if (opts->no_commit) {
470                 /*
471                  * We do not intend to commit immediately.  We just want to
472                  * merge the differences in, so let's compute the tree
473                  * that represents the "current" state for merge-recursive
474                  * to work on.
475                  */
476                 if (write_cache_as_tree(head, 0, NULL))
477                         die (_("Your index file is unmerged."));
478         } else {
479                 unborn = get_sha1("HEAD", head);
480                 if (unborn)
481                         hashcpy(head, EMPTY_TREE_SHA1_BIN);
482                 if (index_differs_from(unborn ? EMPTY_TREE_SHA1_HEX : "HEAD", 0))
483                         return error_dirty_index(opts);
484         }
485         discard_cache();
486
487         if (!commit->parents) {
488                 parent = NULL;
489         }
490         else if (commit->parents->next) {
491                 /* Reverting or cherry-picking a merge commit */
492                 int cnt;
493                 struct commit_list *p;
494
495                 if (!opts->mainline)
496                         return error(_("Commit %s is a merge but no -m option was given."),
497                                 sha1_to_hex(commit->object.sha1));
498
499                 for (cnt = 1, p = commit->parents;
500                      cnt != opts->mainline && p;
501                      cnt++)
502                         p = p->next;
503                 if (cnt != opts->mainline || !p)
504                         return error(_("Commit %s does not have parent %d"),
505                                 sha1_to_hex(commit->object.sha1), opts->mainline);
506                 parent = p->item;
507         } else if (0 < opts->mainline)
508                 return error(_("Mainline was specified but commit %s is not a merge."),
509                         sha1_to_hex(commit->object.sha1));
510         else
511                 parent = commit->parents->item;
512
513         if (opts->allow_ff &&
514             ((parent && !hashcmp(parent->object.sha1, head)) ||
515              (!parent && unborn)))
516                 return fast_forward_to(commit->object.sha1, head, unborn, opts);
517
518         if (parent && parse_commit(parent) < 0)
519                 /* TRANSLATORS: The first %s will be "revert" or
520                    "cherry-pick", the second %s a SHA1 */
521                 return error(_("%s: cannot parse parent commit %s"),
522                         action_name(opts), sha1_to_hex(parent->object.sha1));
523
524         if (get_message(commit, &msg) != 0)
525                 return error(_("Cannot get commit message for %s"),
526                         sha1_to_hex(commit->object.sha1));
527
528         /*
529          * "commit" is an existing commit.  We would want to apply
530          * the difference it introduces since its first parent "prev"
531          * on top of the current HEAD if we are cherry-pick.  Or the
532          * reverse of it if we are revert.
533          */
534
535         defmsg = git_pathdup("MERGE_MSG");
536
537         if (opts->action == REPLAY_REVERT) {
538                 base = commit;
539                 base_label = msg.label;
540                 next = parent;
541                 next_label = msg.parent_label;
542                 strbuf_addstr(&msgbuf, "Revert \"");
543                 strbuf_addstr(&msgbuf, msg.subject);
544                 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
545                 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
546
547                 if (commit->parents && commit->parents->next) {
548                         strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
549                         strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
550                 }
551                 strbuf_addstr(&msgbuf, ".\n");
552         } else {
553                 const char *p;
554
555                 base = parent;
556                 base_label = msg.parent_label;
557                 next = commit;
558                 next_label = msg.label;
559
560                 /*
561                  * Append the commit log message to msgbuf; it starts
562                  * after the tree, parent, author, committer
563                  * information followed by "\n\n".
564                  */
565                 p = strstr(msg.message, "\n\n");
566                 if (p) {
567                         p += 2;
568                         strbuf_addstr(&msgbuf, p);
569                 }
570
571                 if (opts->record_origin) {
572                         if (!has_conforming_footer(&msgbuf, NULL, 0))
573                                 strbuf_addch(&msgbuf, '\n');
574                         strbuf_addstr(&msgbuf, cherry_picked_prefix);
575                         strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
576                         strbuf_addstr(&msgbuf, ")\n");
577                 }
578         }
579
580         if (!opts->strategy || !strcmp(opts->strategy, "recursive") || opts->action == REPLAY_REVERT) {
581                 res = do_recursive_merge(base, next, base_label, next_label,
582                                          head, &msgbuf, opts);
583                 write_message(&msgbuf, defmsg);
584         } else {
585                 struct commit_list *common = NULL;
586                 struct commit_list *remotes = NULL;
587
588                 write_message(&msgbuf, defmsg);
589
590                 commit_list_insert(base, &common);
591                 commit_list_insert(next, &remotes);
592                 res = try_merge_command(opts->strategy, opts->xopts_nr, opts->xopts,
593                                         common, sha1_to_hex(head), remotes);
594                 free_commit_list(common);
595                 free_commit_list(remotes);
596         }
597
598         /*
599          * If the merge was clean or if it failed due to conflict, we write
600          * CHERRY_PICK_HEAD for the subsequent invocation of commit to use.
601          * However, if the merge did not even start, then we don't want to
602          * write it at all.
603          */
604         if (opts->action == REPLAY_PICK && !opts->no_commit && (res == 0 || res == 1))
605                 write_cherry_pick_head(commit, "CHERRY_PICK_HEAD");
606         if (opts->action == REPLAY_REVERT && ((opts->no_commit && res == 0) || res == 1))
607                 write_cherry_pick_head(commit, "REVERT_HEAD");
608
609         if (res) {
610                 error(opts->action == REPLAY_REVERT
611                       ? _("could not revert %s... %s")
612                       : _("could not apply %s... %s"),
613                       find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV),
614                       msg.subject);
615                 print_advice(res == 1, opts);
616                 rerere(opts->allow_rerere_auto);
617                 goto leave;
618         }
619
620         allow = allow_empty(opts, commit);
621         if (allow < 0) {
622                 res = allow;
623                 goto leave;
624         }
625         if (!opts->no_commit)
626                 res = run_git_commit(defmsg, opts, allow);
627
628 leave:
629         free_message(commit, &msg);
630         free(defmsg);
631
632         return res;
633 }
634
635 static void prepare_revs(struct replay_opts *opts)
636 {
637         /*
638          * picking (but not reverting) ranges (but not individual revisions)
639          * should be done in reverse
640          */
641         if (opts->action == REPLAY_PICK && !opts->revs->no_walk)
642                 opts->revs->reverse ^= 1;
643
644         if (prepare_revision_walk(opts->revs))
645                 die(_("revision walk setup failed"));
646
647         if (!opts->revs->commits)
648                 die(_("empty commit set passed"));
649 }
650
651 static void read_and_refresh_cache(struct replay_opts *opts)
652 {
653         static struct lock_file index_lock;
654         int index_fd = hold_locked_index(&index_lock, 0);
655         if (read_index_preload(&the_index, NULL) < 0)
656                 die(_("git %s: failed to read the index"), action_name(opts));
657         refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
658         if (the_index.cache_changed && index_fd >= 0) {
659                 if (write_locked_index(&the_index, &index_lock, COMMIT_LOCK))
660                         die(_("git %s: failed to refresh the index"), action_name(opts));
661         }
662         rollback_lock_file(&index_lock);
663 }
664
665 static int format_todo(struct strbuf *buf, struct commit_list *todo_list,
666                 struct replay_opts *opts)
667 {
668         struct commit_list *cur = NULL;
669         const char *sha1_abbrev = NULL;
670         const char *action_str = opts->action == REPLAY_REVERT ? "revert" : "pick";
671         const char *subject;
672         int subject_len;
673
674         for (cur = todo_list; cur; cur = cur->next) {
675                 const char *commit_buffer = get_commit_buffer(cur->item, NULL);
676                 sha1_abbrev = find_unique_abbrev(cur->item->object.sha1, DEFAULT_ABBREV);
677                 subject_len = find_commit_subject(commit_buffer, &subject);
678                 strbuf_addf(buf, "%s %s %.*s\n", action_str, sha1_abbrev,
679                         subject_len, subject);
680                 unuse_commit_buffer(cur->item, commit_buffer);
681         }
682         return 0;
683 }
684
685 static struct commit *parse_insn_line(char *bol, char *eol, struct replay_opts *opts)
686 {
687         unsigned char commit_sha1[20];
688         enum replay_action action;
689         char *end_of_object_name;
690         int saved, status, padding;
691
692         if (starts_with(bol, "pick")) {
693                 action = REPLAY_PICK;
694                 bol += strlen("pick");
695         } else if (starts_with(bol, "revert")) {
696                 action = REPLAY_REVERT;
697                 bol += strlen("revert");
698         } else
699                 return NULL;
700
701         /* Eat up extra spaces/ tabs before object name */
702         padding = strspn(bol, " \t");
703         if (!padding)
704                 return NULL;
705         bol += padding;
706
707         end_of_object_name = bol + strcspn(bol, " \t\n");
708         saved = *end_of_object_name;
709         *end_of_object_name = '\0';
710         status = get_sha1(bol, commit_sha1);
711         *end_of_object_name = saved;
712
713         /*
714          * Verify that the action matches up with the one in
715          * opts; we don't support arbitrary instructions
716          */
717         if (action != opts->action) {
718                 const char *action_str;
719                 action_str = action == REPLAY_REVERT ? "revert" : "cherry-pick";
720                 error(_("Cannot %s during a %s"), action_str, action_name(opts));
721                 return NULL;
722         }
723
724         if (status < 0)
725                 return NULL;
726
727         return lookup_commit_reference(commit_sha1);
728 }
729
730 static int parse_insn_buffer(char *buf, struct commit_list **todo_list,
731                         struct replay_opts *opts)
732 {
733         struct commit_list **next = todo_list;
734         struct commit *commit;
735         char *p = buf;
736         int i;
737
738         for (i = 1; *p; i++) {
739                 char *eol = strchrnul(p, '\n');
740                 commit = parse_insn_line(p, eol, opts);
741                 if (!commit)
742                         return error(_("Could not parse line %d."), i);
743                 next = commit_list_append(commit, next);
744                 p = *eol ? eol + 1 : eol;
745         }
746         if (!*todo_list)
747                 return error(_("No commits parsed."));
748         return 0;
749 }
750
751 static void read_populate_todo(struct commit_list **todo_list,
752                         struct replay_opts *opts)
753 {
754         const char *todo_file = git_path(SEQ_TODO_FILE);
755         struct strbuf buf = STRBUF_INIT;
756         int fd, res;
757
758         fd = open(todo_file, O_RDONLY);
759         if (fd < 0)
760                 die_errno(_("Could not open %s"), todo_file);
761         if (strbuf_read(&buf, fd, 0) < 0) {
762                 close(fd);
763                 strbuf_release(&buf);
764                 die(_("Could not read %s."), todo_file);
765         }
766         close(fd);
767
768         res = parse_insn_buffer(buf.buf, todo_list, opts);
769         strbuf_release(&buf);
770         if (res)
771                 die(_("Unusable instruction sheet: %s"), todo_file);
772 }
773
774 static int populate_opts_cb(const char *key, const char *value, void *data)
775 {
776         struct replay_opts *opts = data;
777         int error_flag = 1;
778
779         if (!value)
780                 error_flag = 0;
781         else if (!strcmp(key, "options.no-commit"))
782                 opts->no_commit = git_config_bool_or_int(key, value, &error_flag);
783         else if (!strcmp(key, "options.edit"))
784                 opts->edit = git_config_bool_or_int(key, value, &error_flag);
785         else if (!strcmp(key, "options.signoff"))
786                 opts->signoff = git_config_bool_or_int(key, value, &error_flag);
787         else if (!strcmp(key, "options.record-origin"))
788                 opts->record_origin = git_config_bool_or_int(key, value, &error_flag);
789         else if (!strcmp(key, "options.allow-ff"))
790                 opts->allow_ff = git_config_bool_or_int(key, value, &error_flag);
791         else if (!strcmp(key, "options.mainline"))
792                 opts->mainline = git_config_int(key, value);
793         else if (!strcmp(key, "options.strategy"))
794                 git_config_string(&opts->strategy, key, value);
795         else if (!strcmp(key, "options.gpg-sign"))
796                 git_config_string(&opts->gpg_sign, key, value);
797         else if (!strcmp(key, "options.strategy-option")) {
798                 ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
799                 opts->xopts[opts->xopts_nr++] = xstrdup(value);
800         } else
801                 return error(_("Invalid key: %s"), key);
802
803         if (!error_flag)
804                 return error(_("Invalid value for %s: %s"), key, value);
805
806         return 0;
807 }
808
809 static void read_populate_opts(struct replay_opts **opts_ptr)
810 {
811         const char *opts_file = git_path(SEQ_OPTS_FILE);
812
813         if (!file_exists(opts_file))
814                 return;
815         if (git_config_from_file(populate_opts_cb, opts_file, *opts_ptr) < 0)
816                 die(_("Malformed options sheet: %s"), opts_file);
817 }
818
819 static void walk_revs_populate_todo(struct commit_list **todo_list,
820                                 struct replay_opts *opts)
821 {
822         struct commit *commit;
823         struct commit_list **next;
824
825         prepare_revs(opts);
826
827         next = todo_list;
828         while ((commit = get_revision(opts->revs)))
829                 next = commit_list_append(commit, next);
830 }
831
832 static int create_seq_dir(void)
833 {
834         const char *seq_dir = git_path(SEQ_DIR);
835
836         if (file_exists(seq_dir)) {
837                 error(_("a cherry-pick or revert is already in progress"));
838                 advise(_("try \"git cherry-pick (--continue | --quit | --abort)\""));
839                 return -1;
840         }
841         else if (mkdir(seq_dir, 0777) < 0)
842                 die_errno(_("Could not create sequencer directory %s"), seq_dir);
843         return 0;
844 }
845
846 static void save_head(const char *head)
847 {
848         const char *head_file = git_path(SEQ_HEAD_FILE);
849         static struct lock_file head_lock;
850         struct strbuf buf = STRBUF_INIT;
851         int fd;
852
853         fd = hold_lock_file_for_update(&head_lock, head_file, LOCK_DIE_ON_ERROR);
854         strbuf_addf(&buf, "%s\n", head);
855         if (write_in_full(fd, buf.buf, buf.len) < 0)
856                 die_errno(_("Could not write to %s"), head_file);
857         if (commit_lock_file(&head_lock) < 0)
858                 die(_("Error wrapping up %s."), head_file);
859 }
860
861 static int reset_for_rollback(const unsigned char *sha1)
862 {
863         const char *argv[4];    /* reset --merge <arg> + NULL */
864         argv[0] = "reset";
865         argv[1] = "--merge";
866         argv[2] = sha1_to_hex(sha1);
867         argv[3] = NULL;
868         return run_command_v_opt(argv, RUN_GIT_CMD);
869 }
870
871 static int rollback_single_pick(void)
872 {
873         unsigned char head_sha1[20];
874
875         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
876             !file_exists(git_path("REVERT_HEAD")))
877                 return error(_("no cherry-pick or revert in progress"));
878         if (read_ref_full("HEAD", 0, head_sha1, NULL))
879                 return error(_("cannot resolve HEAD"));
880         if (is_null_sha1(head_sha1))
881                 return error(_("cannot abort from a branch yet to be born"));
882         return reset_for_rollback(head_sha1);
883 }
884
885 static int sequencer_rollback(struct replay_opts *opts)
886 {
887         const char *filename;
888         FILE *f;
889         unsigned char sha1[20];
890         struct strbuf buf = STRBUF_INIT;
891
892         filename = git_path(SEQ_HEAD_FILE);
893         f = fopen(filename, "r");
894         if (!f && errno == ENOENT) {
895                 /*
896                  * There is no multiple-cherry-pick in progress.
897                  * If CHERRY_PICK_HEAD or REVERT_HEAD indicates
898                  * a single-cherry-pick in progress, abort that.
899                  */
900                 return rollback_single_pick();
901         }
902         if (!f)
903                 return error(_("cannot open %s: %s"), filename,
904                                                 strerror(errno));
905         if (strbuf_getline(&buf, f, '\n')) {
906                 error(_("cannot read %s: %s"), filename, ferror(f) ?
907                         strerror(errno) : _("unexpected end of file"));
908                 fclose(f);
909                 goto fail;
910         }
911         fclose(f);
912         if (get_sha1_hex(buf.buf, sha1) || buf.buf[40] != '\0') {
913                 error(_("stored pre-cherry-pick HEAD file '%s' is corrupt"),
914                         filename);
915                 goto fail;
916         }
917         if (reset_for_rollback(sha1))
918                 goto fail;
919         remove_sequencer_state();
920         strbuf_release(&buf);
921         return 0;
922 fail:
923         strbuf_release(&buf);
924         return -1;
925 }
926
927 static void save_todo(struct commit_list *todo_list, struct replay_opts *opts)
928 {
929         const char *todo_file = git_path(SEQ_TODO_FILE);
930         static struct lock_file todo_lock;
931         struct strbuf buf = STRBUF_INIT;
932         int fd;
933
934         fd = hold_lock_file_for_update(&todo_lock, todo_file, LOCK_DIE_ON_ERROR);
935         if (format_todo(&buf, todo_list, opts) < 0)
936                 die(_("Could not format %s."), todo_file);
937         if (write_in_full(fd, buf.buf, buf.len) < 0) {
938                 strbuf_release(&buf);
939                 die_errno(_("Could not write to %s"), todo_file);
940         }
941         if (commit_lock_file(&todo_lock) < 0) {
942                 strbuf_release(&buf);
943                 die(_("Error wrapping up %s."), todo_file);
944         }
945         strbuf_release(&buf);
946 }
947
948 static void save_opts(struct replay_opts *opts)
949 {
950         const char *opts_file = git_path(SEQ_OPTS_FILE);
951
952         if (opts->no_commit)
953                 git_config_set_in_file(opts_file, "options.no-commit", "true");
954         if (opts->edit)
955                 git_config_set_in_file(opts_file, "options.edit", "true");
956         if (opts->signoff)
957                 git_config_set_in_file(opts_file, "options.signoff", "true");
958         if (opts->record_origin)
959                 git_config_set_in_file(opts_file, "options.record-origin", "true");
960         if (opts->allow_ff)
961                 git_config_set_in_file(opts_file, "options.allow-ff", "true");
962         if (opts->mainline) {
963                 struct strbuf buf = STRBUF_INIT;
964                 strbuf_addf(&buf, "%d", opts->mainline);
965                 git_config_set_in_file(opts_file, "options.mainline", buf.buf);
966                 strbuf_release(&buf);
967         }
968         if (opts->strategy)
969                 git_config_set_in_file(opts_file, "options.strategy", opts->strategy);
970         if (opts->gpg_sign)
971                 git_config_set_in_file(opts_file, "options.gpg-sign", opts->gpg_sign);
972         if (opts->xopts) {
973                 int i;
974                 for (i = 0; i < opts->xopts_nr; i++)
975                         git_config_set_multivar_in_file(opts_file,
976                                                         "options.strategy-option",
977                                                         opts->xopts[i], "^$", 0);
978         }
979 }
980
981 static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
982 {
983         struct commit_list *cur;
984         int res;
985
986         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
987         if (opts->allow_ff)
988                 assert(!(opts->signoff || opts->no_commit ||
989                                 opts->record_origin || opts->edit));
990         read_and_refresh_cache(opts);
991
992         for (cur = todo_list; cur; cur = cur->next) {
993                 save_todo(cur, opts);
994                 res = do_pick_commit(cur->item, opts);
995                 if (res)
996                         return res;
997         }
998
999         /*
1000          * Sequence of picks finished successfully; cleanup by
1001          * removing the .git/sequencer directory
1002          */
1003         remove_sequencer_state();
1004         return 0;
1005 }
1006
1007 static int continue_single_pick(void)
1008 {
1009         const char *argv[] = { "commit", NULL };
1010
1011         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
1012             !file_exists(git_path("REVERT_HEAD")))
1013                 return error(_("no cherry-pick or revert in progress"));
1014         return run_command_v_opt(argv, RUN_GIT_CMD);
1015 }
1016
1017 static int sequencer_continue(struct replay_opts *opts)
1018 {
1019         struct commit_list *todo_list = NULL;
1020
1021         if (!file_exists(git_path(SEQ_TODO_FILE)))
1022                 return continue_single_pick();
1023         read_populate_opts(&opts);
1024         read_populate_todo(&todo_list, opts);
1025
1026         /* Verify that the conflict has been resolved */
1027         if (file_exists(git_path("CHERRY_PICK_HEAD")) ||
1028             file_exists(git_path("REVERT_HEAD"))) {
1029                 int ret = continue_single_pick();
1030                 if (ret)
1031                         return ret;
1032         }
1033         if (index_differs_from("HEAD", 0))
1034                 return error_dirty_index(opts);
1035         todo_list = todo_list->next;
1036         return pick_commits(todo_list, opts);
1037 }
1038
1039 static int single_pick(struct commit *cmit, struct replay_opts *opts)
1040 {
1041         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
1042         return do_pick_commit(cmit, opts);
1043 }
1044
1045 int sequencer_pick_revisions(struct replay_opts *opts)
1046 {
1047         struct commit_list *todo_list = NULL;
1048         unsigned char sha1[20];
1049         int i;
1050
1051         if (opts->subcommand == REPLAY_NONE)
1052                 assert(opts->revs);
1053
1054         read_and_refresh_cache(opts);
1055
1056         /*
1057          * Decide what to do depending on the arguments; a fresh
1058          * cherry-pick should be handled differently from an existing
1059          * one that is being continued
1060          */
1061         if (opts->subcommand == REPLAY_REMOVE_STATE) {
1062                 remove_sequencer_state();
1063                 return 0;
1064         }
1065         if (opts->subcommand == REPLAY_ROLLBACK)
1066                 return sequencer_rollback(opts);
1067         if (opts->subcommand == REPLAY_CONTINUE)
1068                 return sequencer_continue(opts);
1069
1070         for (i = 0; i < opts->revs->pending.nr; i++) {
1071                 unsigned char sha1[20];
1072                 const char *name = opts->revs->pending.objects[i].name;
1073
1074                 /* This happens when using --stdin. */
1075                 if (!strlen(name))
1076                         continue;
1077
1078                 if (!get_sha1(name, sha1)) {
1079                         if (!lookup_commit_reference_gently(sha1, 1)) {
1080                                 enum object_type type = sha1_object_info(sha1, NULL);
1081                                 die(_("%s: can't cherry-pick a %s"), name, typename(type));
1082                         }
1083                 } else
1084                         die(_("%s: bad revision"), name);
1085         }
1086
1087         /*
1088          * If we were called as "git cherry-pick <commit>", just
1089          * cherry-pick/revert it, set CHERRY_PICK_HEAD /
1090          * REVERT_HEAD, and don't touch the sequencer state.
1091          * This means it is possible to cherry-pick in the middle
1092          * of a cherry-pick sequence.
1093          */
1094         if (opts->revs->cmdline.nr == 1 &&
1095             opts->revs->cmdline.rev->whence == REV_CMD_REV &&
1096             opts->revs->no_walk &&
1097             !opts->revs->cmdline.rev->flags) {
1098                 struct commit *cmit;
1099                 if (prepare_revision_walk(opts->revs))
1100                         die(_("revision walk setup failed"));
1101                 cmit = get_revision(opts->revs);
1102                 if (!cmit || get_revision(opts->revs))
1103                         die("BUG: expected exactly one commit from walk");
1104                 return single_pick(cmit, opts);
1105         }
1106
1107         /*
1108          * Start a new cherry-pick/ revert sequence; but
1109          * first, make sure that an existing one isn't in
1110          * progress
1111          */
1112
1113         walk_revs_populate_todo(&todo_list, opts);
1114         if (create_seq_dir() < 0)
1115                 return -1;
1116         if (get_sha1("HEAD", sha1)) {
1117                 if (opts->action == REPLAY_REVERT)
1118                         return error(_("Can't revert as initial commit"));
1119                 return error(_("Can't cherry-pick into empty head"));
1120         }
1121         save_head(sha1_to_hex(sha1));
1122         save_opts(opts);
1123         return pick_commits(todo_list, opts);
1124 }
1125
1126 void append_signoff(struct strbuf *msgbuf, int ignore_footer, unsigned flag)
1127 {
1128         unsigned no_dup_sob = flag & APPEND_SIGNOFF_DEDUP;
1129         struct strbuf sob = STRBUF_INIT;
1130         int has_footer;
1131
1132         strbuf_addstr(&sob, sign_off_header);
1133         strbuf_addstr(&sob, fmt_name(getenv("GIT_COMMITTER_NAME"),
1134                                 getenv("GIT_COMMITTER_EMAIL")));
1135         strbuf_addch(&sob, '\n');
1136
1137         /*
1138          * If the whole message buffer is equal to the sob, pretend that we
1139          * found a conforming footer with a matching sob
1140          */
1141         if (msgbuf->len - ignore_footer == sob.len &&
1142             !strncmp(msgbuf->buf, sob.buf, sob.len))
1143                 has_footer = 3;
1144         else
1145                 has_footer = has_conforming_footer(msgbuf, &sob, ignore_footer);
1146
1147         if (!has_footer) {
1148                 const char *append_newlines = NULL;
1149                 size_t len = msgbuf->len - ignore_footer;
1150
1151                 if (!len) {
1152                         /*
1153                          * The buffer is completely empty.  Leave foom for
1154                          * the title and body to be filled in by the user.
1155                          */
1156                         append_newlines = "\n\n";
1157                 } else if (msgbuf->buf[len - 1] != '\n') {
1158                         /*
1159                          * Incomplete line.  Complete the line and add a
1160                          * blank one so that there is an empty line between
1161                          * the message body and the sob.
1162                          */
1163                         append_newlines = "\n\n";
1164                 } else if (len == 1) {
1165                         /*
1166                          * Buffer contains a single newline.  Add another
1167                          * so that we leave room for the title and body.
1168                          */
1169                         append_newlines = "\n";
1170                 } else if (msgbuf->buf[len - 2] != '\n') {
1171                         /*
1172                          * Buffer ends with a single newline.  Add another
1173                          * so that there is an empty line between the message
1174                          * body and the sob.
1175                          */
1176                         append_newlines = "\n";
1177                 } /* else, the buffer already ends with two newlines. */
1178
1179                 if (append_newlines)
1180                         strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0,
1181                                 append_newlines, strlen(append_newlines));
1182         }
1183
1184         if (has_footer != 3 && (!no_dup_sob || has_footer != 2))
1185                 strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0,
1186                                 sob.buf, sob.len);
1187
1188         strbuf_release(&sob);
1189 }