Merge branch 'rs/git-gui-use-modern-git-merge-syntax'
[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 GIT_PATH_FUNC(git_path_todo_file, SEQ_TODO_FILE)
25 static GIT_PATH_FUNC(git_path_opts_file, SEQ_OPTS_FILE)
26 static GIT_PATH_FUNC(git_path_seq_dir, SEQ_DIR)
27 static GIT_PATH_FUNC(git_path_head_file, SEQ_HEAD_FILE)
28
29 static int is_rfc2822_line(const char *buf, int len)
30 {
31         int i;
32
33         for (i = 0; i < len; i++) {
34                 int ch = buf[i];
35                 if (ch == ':')
36                         return 1;
37                 if (!isalnum(ch) && ch != '-')
38                         break;
39         }
40
41         return 0;
42 }
43
44 static int is_cherry_picked_from_line(const char *buf, int len)
45 {
46         /*
47          * We only care that it looks roughly like (cherry picked from ...)
48          */
49         return len > strlen(cherry_picked_prefix) + 1 &&
50                 starts_with(buf, cherry_picked_prefix) && buf[len - 1] == ')';
51 }
52
53 /*
54  * Returns 0 for non-conforming footer
55  * Returns 1 for conforming footer
56  * Returns 2 when sob exists within conforming footer
57  * Returns 3 when sob exists within conforming footer as last entry
58  */
59 static int has_conforming_footer(struct strbuf *sb, struct strbuf *sob,
60         int ignore_footer)
61 {
62         char prev;
63         int i, k;
64         int len = sb->len - ignore_footer;
65         const char *buf = sb->buf;
66         int found_sob = 0;
67
68         /* footer must end with newline */
69         if (!len || buf[len - 1] != '\n')
70                 return 0;
71
72         prev = '\0';
73         for (i = len - 1; i > 0; i--) {
74                 char ch = buf[i];
75                 if (prev == '\n' && ch == '\n') /* paragraph break */
76                         break;
77                 prev = ch;
78         }
79
80         /* require at least one blank line */
81         if (prev != '\n' || buf[i] != '\n')
82                 return 0;
83
84         /* advance to start of last paragraph */
85         while (i < len - 1 && buf[i] == '\n')
86                 i++;
87
88         for (; i < len; i = k) {
89                 int found_rfc2822;
90
91                 for (k = i; k < len && buf[k] != '\n'; k++)
92                         ; /* do nothing */
93                 k++;
94
95                 found_rfc2822 = is_rfc2822_line(buf + i, k - i - 1);
96                 if (found_rfc2822 && sob &&
97                     !strncmp(buf + i, sob->buf, sob->len))
98                         found_sob = k;
99
100                 if (!(found_rfc2822 ||
101                       is_cherry_picked_from_line(buf + i, k - i - 1)))
102                         return 0;
103         }
104         if (found_sob == i)
105                 return 3;
106         if (found_sob)
107                 return 2;
108         return 1;
109 }
110
111 static void remove_sequencer_state(void)
112 {
113         struct strbuf seq_dir = STRBUF_INIT;
114
115         strbuf_addstr(&seq_dir, git_path(SEQ_DIR));
116         remove_dir_recursively(&seq_dir, 0);
117         strbuf_release(&seq_dir);
118 }
119
120 static const char *action_name(const struct replay_opts *opts)
121 {
122         return opts->action == REPLAY_REVERT ? "revert" : "cherry-pick";
123 }
124
125 struct commit_message {
126         char *parent_label;
127         char *label;
128         char *subject;
129         const char *message;
130 };
131
132 static int get_message(struct commit *commit, struct commit_message *out)
133 {
134         const char *abbrev, *subject;
135         int subject_len;
136
137         out->message = logmsg_reencode(commit, NULL, get_commit_output_encoding());
138         abbrev = find_unique_abbrev(commit->object.oid.hash, DEFAULT_ABBREV);
139
140         subject_len = find_commit_subject(out->message, &subject);
141
142         out->subject = xmemdupz(subject, subject_len);
143         out->label = xstrfmt("%s... %s", abbrev, out->subject);
144         out->parent_label = xstrfmt("parent of %s", out->label);
145
146         return 0;
147 }
148
149 static void free_message(struct commit *commit, struct commit_message *msg)
150 {
151         free(msg->parent_label);
152         free(msg->label);
153         free(msg->subject);
154         unuse_commit_buffer(commit, msg->message);
155 }
156
157 static void print_advice(int show_hint, struct replay_opts *opts)
158 {
159         char *msg = getenv("GIT_CHERRY_PICK_HELP");
160
161         if (msg) {
162                 fprintf(stderr, "%s\n", msg);
163                 /*
164                  * A conflict has occurred but the porcelain
165                  * (typically rebase --interactive) wants to take care
166                  * of the commit itself so remove CHERRY_PICK_HEAD
167                  */
168                 unlink(git_path_cherry_pick_head());
169                 return;
170         }
171
172         if (show_hint) {
173                 if (opts->no_commit)
174                         advise(_("after resolving the conflicts, mark the corrected paths\n"
175                                  "with 'git add <paths>' or 'git rm <paths>'"));
176                 else
177                         advise(_("after resolving the conflicts, mark the corrected paths\n"
178                                  "with 'git add <paths>' or 'git rm <paths>'\n"
179                                  "and commit the result with 'git commit'"));
180         }
181 }
182
183 static int write_message(struct strbuf *msgbuf, const char *filename)
184 {
185         static struct lock_file msg_file;
186
187         int msg_fd = hold_lock_file_for_update(&msg_file, filename, 0);
188         if (msg_fd < 0)
189                 return error_errno(_("Could not lock '%s'"), filename);
190         if (write_in_full(msg_fd, msgbuf->buf, msgbuf->len) < 0)
191                 return error_errno(_("Could not write to %s"), filename);
192         strbuf_release(msgbuf);
193         if (commit_lock_file(&msg_file) < 0)
194                 return error(_("Error wrapping up %s."), filename);
195
196         return 0;
197 }
198
199 static struct tree *empty_tree(void)
200 {
201         return lookup_tree(EMPTY_TREE_SHA1_BIN);
202 }
203
204 static int error_dirty_index(struct replay_opts *opts)
205 {
206         if (read_cache_unmerged())
207                 return error_resolve_conflict(action_name(opts));
208
209         /* Different translation strings for cherry-pick and revert */
210         if (opts->action == REPLAY_PICK)
211                 error(_("Your local changes would be overwritten by cherry-pick."));
212         else
213                 error(_("Your local changes would be overwritten by revert."));
214
215         if (advice_commit_before_merge)
216                 advise(_("Commit your changes or stash them to proceed."));
217         return -1;
218 }
219
220 static int fast_forward_to(const unsigned char *to, const unsigned char *from,
221                         int unborn, struct replay_opts *opts)
222 {
223         struct ref_transaction *transaction;
224         struct strbuf sb = STRBUF_INIT;
225         struct strbuf err = STRBUF_INIT;
226
227         read_cache();
228         if (checkout_fast_forward(from, to, 1))
229                 return -1; /* the callee should have complained already */
230
231         strbuf_addf(&sb, _("%s: fast-forward"), action_name(opts));
232
233         transaction = ref_transaction_begin(&err);
234         if (!transaction ||
235             ref_transaction_update(transaction, "HEAD",
236                                    to, unborn ? null_sha1 : from,
237                                    0, sb.buf, &err) ||
238             ref_transaction_commit(transaction, &err)) {
239                 ref_transaction_free(transaction);
240                 error("%s", err.buf);
241                 strbuf_release(&sb);
242                 strbuf_release(&err);
243                 return -1;
244         }
245
246         strbuf_release(&sb);
247         strbuf_release(&err);
248         ref_transaction_free(transaction);
249         return 0;
250 }
251
252 void append_conflicts_hint(struct strbuf *msgbuf)
253 {
254         int i;
255
256         strbuf_addch(msgbuf, '\n');
257         strbuf_commented_addf(msgbuf, "Conflicts:\n");
258         for (i = 0; i < active_nr;) {
259                 const struct cache_entry *ce = active_cache[i++];
260                 if (ce_stage(ce)) {
261                         strbuf_commented_addf(msgbuf, "\t%s\n", ce->name);
262                         while (i < active_nr && !strcmp(ce->name,
263                                                         active_cache[i]->name))
264                                 i++;
265                 }
266         }
267 }
268
269 static int do_recursive_merge(struct commit *base, struct commit *next,
270                               const char *base_label, const char *next_label,
271                               unsigned char *head, struct strbuf *msgbuf,
272                               struct replay_opts *opts)
273 {
274         struct merge_options o;
275         struct tree *result, *next_tree, *base_tree, *head_tree;
276         int clean;
277         const char **xopt;
278         static struct lock_file index_lock;
279
280         hold_locked_index(&index_lock, 1);
281
282         read_cache();
283
284         init_merge_options(&o);
285         o.ancestor = base ? base_label : "(empty tree)";
286         o.branch1 = "HEAD";
287         o.branch2 = next ? next_label : "(empty tree)";
288
289         head_tree = parse_tree_indirect(head);
290         next_tree = next ? next->tree : empty_tree();
291         base_tree = base ? base->tree : empty_tree();
292
293         for (xopt = opts->xopts; xopt != opts->xopts + opts->xopts_nr; xopt++)
294                 parse_merge_opt(&o, *xopt);
295
296         clean = merge_trees(&o,
297                             head_tree,
298                             next_tree, base_tree, &result);
299         strbuf_release(&o.obuf);
300         if (clean < 0)
301                 return clean;
302
303         if (active_cache_changed &&
304             write_locked_index(&the_index, &index_lock, COMMIT_LOCK))
305                 /* TRANSLATORS: %s will be "revert" or "cherry-pick" */
306                 return error(_("%s: Unable to write new index file"),
307                         action_name(opts));
308         rollback_lock_file(&index_lock);
309
310         if (opts->signoff)
311                 append_signoff(msgbuf, 0, 0);
312
313         if (!clean)
314                 append_conflicts_hint(msgbuf);
315
316         return !clean;
317 }
318
319 static int is_index_unchanged(void)
320 {
321         unsigned char head_sha1[20];
322         struct commit *head_commit;
323
324         if (!resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, head_sha1, NULL))
325                 return error(_("Could not resolve HEAD commit\n"));
326
327         head_commit = lookup_commit(head_sha1);
328
329         /*
330          * If head_commit is NULL, check_commit, called from
331          * lookup_commit, would have indicated that head_commit is not
332          * a commit object already.  parse_commit() will return failure
333          * without further complaints in such a case.  Otherwise, if
334          * the commit is invalid, parse_commit() will complain.  So
335          * there is nothing for us to say here.  Just return failure.
336          */
337         if (parse_commit(head_commit))
338                 return -1;
339
340         if (!active_cache_tree)
341                 active_cache_tree = cache_tree();
342
343         if (!cache_tree_fully_valid(active_cache_tree))
344                 if (cache_tree_update(&the_index, 0))
345                         return error(_("Unable to update cache tree\n"));
346
347         return !hashcmp(active_cache_tree->sha1, head_commit->tree->object.oid.hash);
348 }
349
350 /*
351  * If we are cherry-pick, and if the merge did not result in
352  * hand-editing, we will hit this commit and inherit the original
353  * author date and name.
354  * If we are revert, or if our cherry-pick results in a hand merge,
355  * we had better say that the current user is responsible for that.
356  */
357 static int run_git_commit(const char *defmsg, struct replay_opts *opts,
358                           int allow_empty)
359 {
360         struct argv_array array;
361         int rc;
362         const char *value;
363
364         argv_array_init(&array);
365         argv_array_push(&array, "commit");
366         argv_array_push(&array, "-n");
367
368         if (opts->gpg_sign)
369                 argv_array_pushf(&array, "-S%s", opts->gpg_sign);
370         if (opts->signoff)
371                 argv_array_push(&array, "-s");
372         if (!opts->edit) {
373                 argv_array_push(&array, "-F");
374                 argv_array_push(&array, defmsg);
375                 if (!opts->signoff &&
376                     !opts->record_origin &&
377                     git_config_get_value("commit.cleanup", &value))
378                         argv_array_push(&array, "--cleanup=verbatim");
379         }
380
381         if (allow_empty)
382                 argv_array_push(&array, "--allow-empty");
383
384         if (opts->allow_empty_message)
385                 argv_array_push(&array, "--allow-empty-message");
386
387         rc = run_command_v_opt(array.argv, RUN_GIT_CMD);
388         argv_array_clear(&array);
389         return rc;
390 }
391
392 static int is_original_commit_empty(struct commit *commit)
393 {
394         const unsigned char *ptree_sha1;
395
396         if (parse_commit(commit))
397                 return error(_("Could not parse commit %s\n"),
398                              oid_to_hex(&commit->object.oid));
399         if (commit->parents) {
400                 struct commit *parent = commit->parents->item;
401                 if (parse_commit(parent))
402                         return error(_("Could not parse parent commit %s\n"),
403                                 oid_to_hex(&parent->object.oid));
404                 ptree_sha1 = parent->tree->object.oid.hash;
405         } else {
406                 ptree_sha1 = EMPTY_TREE_SHA1_BIN; /* commit is root */
407         }
408
409         return !hashcmp(ptree_sha1, commit->tree->object.oid.hash);
410 }
411
412 /*
413  * Do we run "git commit" with "--allow-empty"?
414  */
415 static int allow_empty(struct replay_opts *opts, struct commit *commit)
416 {
417         int index_unchanged, empty_commit;
418
419         /*
420          * Three cases:
421          *
422          * (1) we do not allow empty at all and error out.
423          *
424          * (2) we allow ones that were initially empty, but
425          * forbid the ones that become empty;
426          *
427          * (3) we allow both.
428          */
429         if (!opts->allow_empty)
430                 return 0; /* let "git commit" barf as necessary */
431
432         index_unchanged = is_index_unchanged();
433         if (index_unchanged < 0)
434                 return index_unchanged;
435         if (!index_unchanged)
436                 return 0; /* we do not have to say --allow-empty */
437
438         if (opts->keep_redundant_commits)
439                 return 1;
440
441         empty_commit = is_original_commit_empty(commit);
442         if (empty_commit < 0)
443                 return empty_commit;
444         if (!empty_commit)
445                 return 0;
446         else
447                 return 1;
448 }
449
450 static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
451 {
452         unsigned char head[20];
453         struct commit *base, *next, *parent;
454         const char *base_label, *next_label;
455         struct commit_message msg = { NULL, NULL, NULL, NULL };
456         struct strbuf msgbuf = STRBUF_INIT;
457         int res, unborn = 0, allow;
458
459         if (opts->no_commit) {
460                 /*
461                  * We do not intend to commit immediately.  We just want to
462                  * merge the differences in, so let's compute the tree
463                  * that represents the "current" state for merge-recursive
464                  * to work on.
465                  */
466                 if (write_cache_as_tree(head, 0, NULL))
467                         return error(_("Your index file is unmerged."));
468         } else {
469                 unborn = get_sha1("HEAD", head);
470                 if (unborn)
471                         hashcpy(head, EMPTY_TREE_SHA1_BIN);
472                 if (index_differs_from(unborn ? EMPTY_TREE_SHA1_HEX : "HEAD", 0))
473                         return error_dirty_index(opts);
474         }
475         discard_cache();
476
477         if (!commit->parents) {
478                 parent = NULL;
479         }
480         else if (commit->parents->next) {
481                 /* Reverting or cherry-picking a merge commit */
482                 int cnt;
483                 struct commit_list *p;
484
485                 if (!opts->mainline)
486                         return error(_("Commit %s is a merge but no -m option was given."),
487                                 oid_to_hex(&commit->object.oid));
488
489                 for (cnt = 1, p = commit->parents;
490                      cnt != opts->mainline && p;
491                      cnt++)
492                         p = p->next;
493                 if (cnt != opts->mainline || !p)
494                         return error(_("Commit %s does not have parent %d"),
495                                 oid_to_hex(&commit->object.oid), opts->mainline);
496                 parent = p->item;
497         } else if (0 < opts->mainline)
498                 return error(_("Mainline was specified but commit %s is not a merge."),
499                         oid_to_hex(&commit->object.oid));
500         else
501                 parent = commit->parents->item;
502
503         if (opts->allow_ff &&
504             ((parent && !hashcmp(parent->object.oid.hash, head)) ||
505              (!parent && unborn)))
506                 return fast_forward_to(commit->object.oid.hash, head, unborn, opts);
507
508         if (parent && parse_commit(parent) < 0)
509                 /* TRANSLATORS: The first %s will be "revert" or
510                    "cherry-pick", the second %s a SHA1 */
511                 return error(_("%s: cannot parse parent commit %s"),
512                         action_name(opts), oid_to_hex(&parent->object.oid));
513
514         if (get_message(commit, &msg) != 0)
515                 return error(_("Cannot get commit message for %s"),
516                         oid_to_hex(&commit->object.oid));
517
518         /*
519          * "commit" is an existing commit.  We would want to apply
520          * the difference it introduces since its first parent "prev"
521          * on top of the current HEAD if we are cherry-pick.  Or the
522          * reverse of it if we are revert.
523          */
524
525         if (opts->action == REPLAY_REVERT) {
526                 base = commit;
527                 base_label = msg.label;
528                 next = parent;
529                 next_label = msg.parent_label;
530                 strbuf_addstr(&msgbuf, "Revert \"");
531                 strbuf_addstr(&msgbuf, msg.subject);
532                 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
533                 strbuf_addstr(&msgbuf, oid_to_hex(&commit->object.oid));
534
535                 if (commit->parents && commit->parents->next) {
536                         strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
537                         strbuf_addstr(&msgbuf, oid_to_hex(&parent->object.oid));
538                 }
539                 strbuf_addstr(&msgbuf, ".\n");
540         } else {
541                 const char *p;
542
543                 base = parent;
544                 base_label = msg.parent_label;
545                 next = commit;
546                 next_label = msg.label;
547
548                 /*
549                  * Append the commit log message to msgbuf; it starts
550                  * after the tree, parent, author, committer
551                  * information followed by "\n\n".
552                  */
553                 p = strstr(msg.message, "\n\n");
554                 if (p)
555                         strbuf_addstr(&msgbuf, skip_blank_lines(p + 2));
556
557                 if (opts->record_origin) {
558                         if (!has_conforming_footer(&msgbuf, NULL, 0))
559                                 strbuf_addch(&msgbuf, '\n');
560                         strbuf_addstr(&msgbuf, cherry_picked_prefix);
561                         strbuf_addstr(&msgbuf, oid_to_hex(&commit->object.oid));
562                         strbuf_addstr(&msgbuf, ")\n");
563                 }
564         }
565
566         if (!opts->strategy || !strcmp(opts->strategy, "recursive") || opts->action == REPLAY_REVERT) {
567                 res = do_recursive_merge(base, next, base_label, next_label,
568                                          head, &msgbuf, opts);
569                 if (res < 0)
570                         return res;
571                 res |= write_message(&msgbuf, git_path_merge_msg());
572         } else {
573                 struct commit_list *common = NULL;
574                 struct commit_list *remotes = NULL;
575
576                 res = write_message(&msgbuf, git_path_merge_msg());
577
578                 commit_list_insert(base, &common);
579                 commit_list_insert(next, &remotes);
580                 res |= try_merge_command(opts->strategy, opts->xopts_nr, opts->xopts,
581                                         common, sha1_to_hex(head), remotes);
582                 free_commit_list(common);
583                 free_commit_list(remotes);
584         }
585
586         /*
587          * If the merge was clean or if it failed due to conflict, we write
588          * CHERRY_PICK_HEAD for the subsequent invocation of commit to use.
589          * However, if the merge did not even start, then we don't want to
590          * write it at all.
591          */
592         if (opts->action == REPLAY_PICK && !opts->no_commit && (res == 0 || res == 1) &&
593             update_ref(NULL, "CHERRY_PICK_HEAD", commit->object.oid.hash, NULL,
594                        REF_NODEREF, UPDATE_REFS_MSG_ON_ERR))
595                 res = -1;
596         if (opts->action == REPLAY_REVERT && ((opts->no_commit && res == 0) || res == 1) &&
597             update_ref(NULL, "REVERT_HEAD", commit->object.oid.hash, NULL,
598                        REF_NODEREF, UPDATE_REFS_MSG_ON_ERR))
599                 res = -1;
600
601         if (res) {
602                 error(opts->action == REPLAY_REVERT
603                       ? _("could not revert %s... %s")
604                       : _("could not apply %s... %s"),
605                       find_unique_abbrev(commit->object.oid.hash, DEFAULT_ABBREV),
606                       msg.subject);
607                 print_advice(res == 1, opts);
608                 rerere(opts->allow_rerere_auto);
609                 goto leave;
610         }
611
612         allow = allow_empty(opts, commit);
613         if (allow < 0) {
614                 res = allow;
615                 goto leave;
616         }
617         if (!opts->no_commit)
618                 res = run_git_commit(git_path_merge_msg(), opts, allow);
619
620 leave:
621         free_message(commit, &msg);
622
623         return res;
624 }
625
626 static int prepare_revs(struct replay_opts *opts)
627 {
628         /*
629          * picking (but not reverting) ranges (but not individual revisions)
630          * should be done in reverse
631          */
632         if (opts->action == REPLAY_PICK && !opts->revs->no_walk)
633                 opts->revs->reverse ^= 1;
634
635         if (prepare_revision_walk(opts->revs))
636                 return error(_("revision walk setup failed"));
637
638         if (!opts->revs->commits)
639                 return error(_("empty commit set passed"));
640         return 0;
641 }
642
643 static int read_and_refresh_cache(struct replay_opts *opts)
644 {
645         static struct lock_file index_lock;
646         int index_fd = hold_locked_index(&index_lock, 0);
647         if (read_index_preload(&the_index, NULL) < 0) {
648                 rollback_lock_file(&index_lock);
649                 return error(_("git %s: failed to read the index"),
650                         action_name(opts));
651         }
652         refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
653         if (the_index.cache_changed && index_fd >= 0) {
654                 if (write_locked_index(&the_index, &index_lock, COMMIT_LOCK)) {
655                         rollback_lock_file(&index_lock);
656                         return error(_("git %s: failed to refresh the index"),
657                                 action_name(opts));
658                 }
659         }
660         rollback_lock_file(&index_lock);
661         return 0;
662 }
663
664 static int format_todo(struct strbuf *buf, struct commit_list *todo_list,
665                 struct replay_opts *opts)
666 {
667         struct commit_list *cur = NULL;
668         const char *sha1_abbrev = NULL;
669         const char *action_str = opts->action == REPLAY_REVERT ? "revert" : "pick";
670         const char *subject;
671         int subject_len;
672
673         for (cur = todo_list; cur; cur = cur->next) {
674                 const char *commit_buffer = get_commit_buffer(cur->item, NULL);
675                 sha1_abbrev = find_unique_abbrev(cur->item->object.oid.hash, DEFAULT_ABBREV);
676                 subject_len = find_commit_subject(commit_buffer, &subject);
677                 strbuf_addf(buf, "%s %s %.*s\n", action_str, sha1_abbrev,
678                         subject_len, subject);
679                 unuse_commit_buffer(cur->item, commit_buffer);
680         }
681         return 0;
682 }
683
684 static struct commit *parse_insn_line(char *bol, char *eol, struct replay_opts *opts)
685 {
686         unsigned char commit_sha1[20];
687         enum replay_action action;
688         char *end_of_object_name;
689         int saved, status, padding;
690
691         if (starts_with(bol, "pick")) {
692                 action = REPLAY_PICK;
693                 bol += strlen("pick");
694         } else if (starts_with(bol, "revert")) {
695                 action = REPLAY_REVERT;
696                 bol += strlen("revert");
697         } else
698                 return NULL;
699
700         /* Eat up extra spaces/ tabs before object name */
701         padding = strspn(bol, " \t");
702         if (!padding)
703                 return NULL;
704         bol += padding;
705
706         end_of_object_name = bol + strcspn(bol, " \t\n");
707         saved = *end_of_object_name;
708         *end_of_object_name = '\0';
709         status = get_sha1(bol, commit_sha1);
710         *end_of_object_name = saved;
711
712         /*
713          * Verify that the action matches up with the one in
714          * opts; we don't support arbitrary instructions
715          */
716         if (action != opts->action) {
717                 if (action == REPLAY_REVERT)
718                       error((opts->action == REPLAY_REVERT)
719                             ? _("Cannot revert during another revert.")
720                             : _("Cannot revert during a cherry-pick."));
721                 else
722                       error((opts->action == REPLAY_REVERT)
723                             ? _("Cannot cherry-pick during a revert.")
724                             : _("Cannot cherry-pick during another cherry-pick."));
725                 return NULL;
726         }
727
728         if (status < 0)
729                 return NULL;
730
731         return lookup_commit_reference(commit_sha1);
732 }
733
734 static int parse_insn_buffer(char *buf, struct commit_list **todo_list,
735                         struct replay_opts *opts)
736 {
737         struct commit_list **next = todo_list;
738         struct commit *commit;
739         char *p = buf;
740         int i;
741
742         for (i = 1; *p; i++) {
743                 char *eol = strchrnul(p, '\n');
744                 commit = parse_insn_line(p, eol, opts);
745                 if (!commit)
746                         return error(_("Could not parse line %d."), i);
747                 next = commit_list_append(commit, next);
748                 p = *eol ? eol + 1 : eol;
749         }
750         if (!*todo_list)
751                 return error(_("No commits parsed."));
752         return 0;
753 }
754
755 static int read_populate_todo(struct commit_list **todo_list,
756                         struct replay_opts *opts)
757 {
758         struct strbuf buf = STRBUF_INIT;
759         int fd, res;
760
761         fd = open(git_path_todo_file(), O_RDONLY);
762         if (fd < 0)
763                 return error_errno(_("Could not open %s"),
764                                    git_path_todo_file());
765         if (strbuf_read(&buf, fd, 0) < 0) {
766                 close(fd);
767                 strbuf_release(&buf);
768                 return error(_("Could not read %s."), git_path_todo_file());
769         }
770         close(fd);
771
772         res = parse_insn_buffer(buf.buf, todo_list, opts);
773         strbuf_release(&buf);
774         if (res)
775                 return error(_("Unusable instruction sheet: %s"),
776                         git_path_todo_file());
777         return 0;
778 }
779
780 static int populate_opts_cb(const char *key, const char *value, void *data)
781 {
782         struct replay_opts *opts = data;
783         int error_flag = 1;
784
785         if (!value)
786                 error_flag = 0;
787         else if (!strcmp(key, "options.no-commit"))
788                 opts->no_commit = git_config_bool_or_int(key, value, &error_flag);
789         else if (!strcmp(key, "options.edit"))
790                 opts->edit = git_config_bool_or_int(key, value, &error_flag);
791         else if (!strcmp(key, "options.signoff"))
792                 opts->signoff = git_config_bool_or_int(key, value, &error_flag);
793         else if (!strcmp(key, "options.record-origin"))
794                 opts->record_origin = git_config_bool_or_int(key, value, &error_flag);
795         else if (!strcmp(key, "options.allow-ff"))
796                 opts->allow_ff = git_config_bool_or_int(key, value, &error_flag);
797         else if (!strcmp(key, "options.mainline"))
798                 opts->mainline = git_config_int(key, value);
799         else if (!strcmp(key, "options.strategy"))
800                 git_config_string(&opts->strategy, key, value);
801         else if (!strcmp(key, "options.gpg-sign"))
802                 git_config_string(&opts->gpg_sign, key, value);
803         else if (!strcmp(key, "options.strategy-option")) {
804                 ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
805                 opts->xopts[opts->xopts_nr++] = xstrdup(value);
806         } else
807                 return error(_("Invalid key: %s"), key);
808
809         if (!error_flag)
810                 return error(_("Invalid value for %s: %s"), key, value);
811
812         return 0;
813 }
814
815 static int read_populate_opts(struct replay_opts **opts)
816 {
817         if (!file_exists(git_path_opts_file()))
818                 return 0;
819         /*
820          * The function git_parse_source(), called from git_config_from_file(),
821          * may die() in case of a syntactically incorrect file. We do not care
822          * about this case, though, because we wrote that file ourselves, so we
823          * are pretty certain that it is syntactically correct.
824          */
825         if (git_config_from_file(populate_opts_cb, git_path_opts_file(), *opts) < 0)
826                 return error(_("Malformed options sheet: %s"),
827                         git_path_opts_file());
828         return 0;
829 }
830
831 static int walk_revs_populate_todo(struct commit_list **todo_list,
832                                 struct replay_opts *opts)
833 {
834         struct commit *commit;
835         struct commit_list **next;
836
837         if (prepare_revs(opts))
838                 return -1;
839
840         next = todo_list;
841         while ((commit = get_revision(opts->revs)))
842                 next = commit_list_append(commit, next);
843         return 0;
844 }
845
846 static int create_seq_dir(void)
847 {
848         if (file_exists(git_path_seq_dir())) {
849                 error(_("a cherry-pick or revert is already in progress"));
850                 advise(_("try \"git cherry-pick (--continue | --quit | --abort)\""));
851                 return -1;
852         }
853         else if (mkdir(git_path_seq_dir(), 0777) < 0)
854                 return error_errno(_("Could not create sequencer directory %s"),
855                                    git_path_seq_dir());
856         return 0;
857 }
858
859 static int save_head(const char *head)
860 {
861         static struct lock_file head_lock;
862         struct strbuf buf = STRBUF_INIT;
863         int fd;
864
865         fd = hold_lock_file_for_update(&head_lock, git_path_head_file(), 0);
866         if (fd < 0) {
867                 rollback_lock_file(&head_lock);
868                 return error_errno(_("Could not lock HEAD"));
869         }
870         strbuf_addf(&buf, "%s\n", head);
871         if (write_in_full(fd, buf.buf, buf.len) < 0) {
872                 rollback_lock_file(&head_lock);
873                 return error_errno(_("Could not write to %s"),
874                                    git_path_head_file());
875         }
876         if (commit_lock_file(&head_lock) < 0) {
877                 rollback_lock_file(&head_lock);
878                 return error(_("Error wrapping up %s."), git_path_head_file());
879         }
880         return 0;
881 }
882
883 static int reset_for_rollback(const unsigned char *sha1)
884 {
885         const char *argv[4];    /* reset --merge <arg> + NULL */
886         argv[0] = "reset";
887         argv[1] = "--merge";
888         argv[2] = sha1_to_hex(sha1);
889         argv[3] = NULL;
890         return run_command_v_opt(argv, RUN_GIT_CMD);
891 }
892
893 static int rollback_single_pick(void)
894 {
895         unsigned char head_sha1[20];
896
897         if (!file_exists(git_path_cherry_pick_head()) &&
898             !file_exists(git_path_revert_head()))
899                 return error(_("no cherry-pick or revert in progress"));
900         if (read_ref_full("HEAD", 0, head_sha1, NULL))
901                 return error(_("cannot resolve HEAD"));
902         if (is_null_sha1(head_sha1))
903                 return error(_("cannot abort from a branch yet to be born"));
904         return reset_for_rollback(head_sha1);
905 }
906
907 static int sequencer_rollback(struct replay_opts *opts)
908 {
909         FILE *f;
910         unsigned char sha1[20];
911         struct strbuf buf = STRBUF_INIT;
912
913         f = fopen(git_path_head_file(), "r");
914         if (!f && errno == ENOENT) {
915                 /*
916                  * There is no multiple-cherry-pick in progress.
917                  * If CHERRY_PICK_HEAD or REVERT_HEAD indicates
918                  * a single-cherry-pick in progress, abort that.
919                  */
920                 return rollback_single_pick();
921         }
922         if (!f)
923                 return error_errno(_("cannot open %s"), git_path_head_file());
924         if (strbuf_getline_lf(&buf, f)) {
925                 error(_("cannot read %s: %s"), git_path_head_file(),
926                       ferror(f) ?  strerror(errno) : _("unexpected end of file"));
927                 fclose(f);
928                 goto fail;
929         }
930         fclose(f);
931         if (get_sha1_hex(buf.buf, sha1) || buf.buf[40] != '\0') {
932                 error(_("stored pre-cherry-pick HEAD file '%s' is corrupt"),
933                         git_path_head_file());
934                 goto fail;
935         }
936         if (is_null_sha1(sha1)) {
937                 error(_("cannot abort from a branch yet to be born"));
938                 goto fail;
939         }
940         if (reset_for_rollback(sha1))
941                 goto fail;
942         remove_sequencer_state();
943         strbuf_release(&buf);
944         return 0;
945 fail:
946         strbuf_release(&buf);
947         return -1;
948 }
949
950 static int save_todo(struct commit_list *todo_list, struct replay_opts *opts)
951 {
952         static struct lock_file todo_lock;
953         struct strbuf buf = STRBUF_INIT;
954         int fd;
955
956         fd = hold_lock_file_for_update(&todo_lock, git_path_todo_file(), 0);
957         if (fd < 0)
958                 return error_errno(_("Could not lock '%s'"),
959                                    git_path_todo_file());
960         if (format_todo(&buf, todo_list, opts) < 0) {
961                 strbuf_release(&buf);
962                 return error(_("Could not format %s."), git_path_todo_file());
963         }
964         if (write_in_full(fd, buf.buf, buf.len) < 0) {
965                 strbuf_release(&buf);
966                 return error_errno(_("Could not write to %s"),
967                                    git_path_todo_file());
968         }
969         if (commit_lock_file(&todo_lock) < 0) {
970                 strbuf_release(&buf);
971                 return error(_("Error wrapping up %s."), git_path_todo_file());
972         }
973         strbuf_release(&buf);
974         return 0;
975 }
976
977 static int save_opts(struct replay_opts *opts)
978 {
979         const char *opts_file = git_path_opts_file();
980         int res = 0;
981
982         if (opts->no_commit)
983                 res |= git_config_set_in_file_gently(opts_file, "options.no-commit", "true");
984         if (opts->edit)
985                 res |= git_config_set_in_file_gently(opts_file, "options.edit", "true");
986         if (opts->signoff)
987                 res |= git_config_set_in_file_gently(opts_file, "options.signoff", "true");
988         if (opts->record_origin)
989                 res |= git_config_set_in_file_gently(opts_file, "options.record-origin", "true");
990         if (opts->allow_ff)
991                 res |= git_config_set_in_file_gently(opts_file, "options.allow-ff", "true");
992         if (opts->mainline) {
993                 struct strbuf buf = STRBUF_INIT;
994                 strbuf_addf(&buf, "%d", opts->mainline);
995                 res |= git_config_set_in_file_gently(opts_file, "options.mainline", buf.buf);
996                 strbuf_release(&buf);
997         }
998         if (opts->strategy)
999                 res |= git_config_set_in_file_gently(opts_file, "options.strategy", opts->strategy);
1000         if (opts->gpg_sign)
1001                 res |= git_config_set_in_file_gently(opts_file, "options.gpg-sign", opts->gpg_sign);
1002         if (opts->xopts) {
1003                 int i;
1004                 for (i = 0; i < opts->xopts_nr; i++)
1005                         res |= git_config_set_multivar_in_file_gently(opts_file,
1006                                                         "options.strategy-option",
1007                                                         opts->xopts[i], "^$", 0);
1008         }
1009         return res;
1010 }
1011
1012 static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
1013 {
1014         struct commit_list *cur;
1015         int res;
1016
1017         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
1018         if (opts->allow_ff)
1019                 assert(!(opts->signoff || opts->no_commit ||
1020                                 opts->record_origin || opts->edit));
1021         if (read_and_refresh_cache(opts))
1022                 return -1;
1023
1024         for (cur = todo_list; cur; cur = cur->next) {
1025                 if (save_todo(cur, opts))
1026                         return -1;
1027                 res = do_pick_commit(cur->item, opts);
1028                 if (res)
1029                         return res;
1030         }
1031
1032         /*
1033          * Sequence of picks finished successfully; cleanup by
1034          * removing the .git/sequencer directory
1035          */
1036         remove_sequencer_state();
1037         return 0;
1038 }
1039
1040 static int continue_single_pick(void)
1041 {
1042         const char *argv[] = { "commit", NULL };
1043
1044         if (!file_exists(git_path_cherry_pick_head()) &&
1045             !file_exists(git_path_revert_head()))
1046                 return error(_("no cherry-pick or revert in progress"));
1047         return run_command_v_opt(argv, RUN_GIT_CMD);
1048 }
1049
1050 static int sequencer_continue(struct replay_opts *opts)
1051 {
1052         struct commit_list *todo_list = NULL;
1053
1054         if (!file_exists(git_path_todo_file()))
1055                 return continue_single_pick();
1056         if (read_populate_opts(&opts) ||
1057                         read_populate_todo(&todo_list, opts))
1058                 return -1;
1059
1060         /* Verify that the conflict has been resolved */
1061         if (file_exists(git_path_cherry_pick_head()) ||
1062             file_exists(git_path_revert_head())) {
1063                 int ret = continue_single_pick();
1064                 if (ret)
1065                         return ret;
1066         }
1067         if (index_differs_from("HEAD", 0))
1068                 return error_dirty_index(opts);
1069         todo_list = todo_list->next;
1070         return pick_commits(todo_list, opts);
1071 }
1072
1073 static int single_pick(struct commit *cmit, struct replay_opts *opts)
1074 {
1075         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
1076         return do_pick_commit(cmit, opts);
1077 }
1078
1079 int sequencer_pick_revisions(struct replay_opts *opts)
1080 {
1081         struct commit_list *todo_list = NULL;
1082         unsigned char sha1[20];
1083         int i;
1084
1085         if (opts->subcommand == REPLAY_NONE)
1086                 assert(opts->revs);
1087
1088         if (read_and_refresh_cache(opts))
1089                 return -1;
1090
1091         /*
1092          * Decide what to do depending on the arguments; a fresh
1093          * cherry-pick should be handled differently from an existing
1094          * one that is being continued
1095          */
1096         if (opts->subcommand == REPLAY_REMOVE_STATE) {
1097                 remove_sequencer_state();
1098                 return 0;
1099         }
1100         if (opts->subcommand == REPLAY_ROLLBACK)
1101                 return sequencer_rollback(opts);
1102         if (opts->subcommand == REPLAY_CONTINUE)
1103                 return sequencer_continue(opts);
1104
1105         for (i = 0; i < opts->revs->pending.nr; i++) {
1106                 unsigned char sha1[20];
1107                 const char *name = opts->revs->pending.objects[i].name;
1108
1109                 /* This happens when using --stdin. */
1110                 if (!strlen(name))
1111                         continue;
1112
1113                 if (!get_sha1(name, sha1)) {
1114                         if (!lookup_commit_reference_gently(sha1, 1)) {
1115                                 enum object_type type = sha1_object_info(sha1, NULL);
1116                                 return error(_("%s: can't cherry-pick a %s"),
1117                                         name, typename(type));
1118                         }
1119                 } else
1120                         return error(_("%s: bad revision"), name);
1121         }
1122
1123         /*
1124          * If we were called as "git cherry-pick <commit>", just
1125          * cherry-pick/revert it, set CHERRY_PICK_HEAD /
1126          * REVERT_HEAD, and don't touch the sequencer state.
1127          * This means it is possible to cherry-pick in the middle
1128          * of a cherry-pick sequence.
1129          */
1130         if (opts->revs->cmdline.nr == 1 &&
1131             opts->revs->cmdline.rev->whence == REV_CMD_REV &&
1132             opts->revs->no_walk &&
1133             !opts->revs->cmdline.rev->flags) {
1134                 struct commit *cmit;
1135                 if (prepare_revision_walk(opts->revs))
1136                         return error(_("revision walk setup failed"));
1137                 cmit = get_revision(opts->revs);
1138                 if (!cmit || get_revision(opts->revs))
1139                         return error("BUG: expected exactly one commit from walk");
1140                 return single_pick(cmit, opts);
1141         }
1142
1143         /*
1144          * Start a new cherry-pick/ revert sequence; but
1145          * first, make sure that an existing one isn't in
1146          * progress
1147          */
1148
1149         if (walk_revs_populate_todo(&todo_list, opts) ||
1150                         create_seq_dir() < 0)
1151                 return -1;
1152         if (get_sha1("HEAD", sha1) && (opts->action == REPLAY_REVERT))
1153                 return error(_("Can't revert as initial commit"));
1154         if (save_head(sha1_to_hex(sha1)))
1155                 return -1;
1156         if (save_opts(opts))
1157                 return -1;
1158         return pick_commits(todo_list, opts);
1159 }
1160
1161 void append_signoff(struct strbuf *msgbuf, int ignore_footer, unsigned flag)
1162 {
1163         unsigned no_dup_sob = flag & APPEND_SIGNOFF_DEDUP;
1164         struct strbuf sob = STRBUF_INIT;
1165         int has_footer;
1166
1167         strbuf_addstr(&sob, sign_off_header);
1168         strbuf_addstr(&sob, fmt_name(getenv("GIT_COMMITTER_NAME"),
1169                                 getenv("GIT_COMMITTER_EMAIL")));
1170         strbuf_addch(&sob, '\n');
1171
1172         /*
1173          * If the whole message buffer is equal to the sob, pretend that we
1174          * found a conforming footer with a matching sob
1175          */
1176         if (msgbuf->len - ignore_footer == sob.len &&
1177             !strncmp(msgbuf->buf, sob.buf, sob.len))
1178                 has_footer = 3;
1179         else
1180                 has_footer = has_conforming_footer(msgbuf, &sob, ignore_footer);
1181
1182         if (!has_footer) {
1183                 const char *append_newlines = NULL;
1184                 size_t len = msgbuf->len - ignore_footer;
1185
1186                 if (!len) {
1187                         /*
1188                          * The buffer is completely empty.  Leave foom for
1189                          * the title and body to be filled in by the user.
1190                          */
1191                         append_newlines = "\n\n";
1192                 } else if (msgbuf->buf[len - 1] != '\n') {
1193                         /*
1194                          * Incomplete line.  Complete the line and add a
1195                          * blank one so that there is an empty line between
1196                          * the message body and the sob.
1197                          */
1198                         append_newlines = "\n\n";
1199                 } else if (len == 1) {
1200                         /*
1201                          * Buffer contains a single newline.  Add another
1202                          * so that we leave room for the title and body.
1203                          */
1204                         append_newlines = "\n";
1205                 } else if (msgbuf->buf[len - 2] != '\n') {
1206                         /*
1207                          * Buffer ends with a single newline.  Add another
1208                          * so that there is an empty line between the message
1209                          * body and the sob.
1210                          */
1211                         append_newlines = "\n";
1212                 } /* else, the buffer already ends with two newlines. */
1213
1214                 if (append_newlines)
1215                         strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0,
1216                                 append_newlines, strlen(append_newlines));
1217         }
1218
1219         if (has_footer != 3 && (!no_dup_sob || has_footer != 2))
1220                 strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0,
1221                                 sob.buf, sob.len);
1222
1223         strbuf_release(&sob);
1224 }