Merge branch 'mg/lib-gpg-ro-safety'
[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 static int do_recursive_merge(struct commit *base, struct commit *next,
271                               const char *base_label, const char *next_label,
272                               unsigned char *head, struct strbuf *msgbuf,
273                               struct replay_opts *opts)
274 {
275         struct merge_options o;
276         struct tree *result, *next_tree, *base_tree, *head_tree;
277         int clean;
278         const char **xopt;
279         static struct lock_file index_lock;
280
281         hold_locked_index(&index_lock, 1);
282
283         read_cache();
284
285         init_merge_options(&o);
286         o.ancestor = base ? base_label : "(empty tree)";
287         o.branch1 = "HEAD";
288         o.branch2 = next ? next_label : "(empty tree)";
289
290         head_tree = parse_tree_indirect(head);
291         next_tree = next ? next->tree : empty_tree();
292         base_tree = base ? base->tree : empty_tree();
293
294         for (xopt = opts->xopts; xopt != opts->xopts + opts->xopts_nr; xopt++)
295                 parse_merge_opt(&o, *xopt);
296
297         clean = merge_trees(&o,
298                             head_tree,
299                             next_tree, base_tree, &result);
300
301         if (active_cache_changed &&
302             write_locked_index(&the_index, &index_lock, COMMIT_LOCK))
303                 /* TRANSLATORS: %s will be "revert" or "cherry-pick" */
304                 die(_("%s: Unable to write new index file"), action_name(opts));
305         rollback_lock_file(&index_lock);
306
307         if (opts->signoff)
308                 append_signoff(msgbuf, 0, 0);
309
310         if (!clean) {
311                 int i;
312                 strbuf_addstr(msgbuf, "\nConflicts:\n");
313                 for (i = 0; i < active_nr;) {
314                         const struct cache_entry *ce = active_cache[i++];
315                         if (ce_stage(ce)) {
316                                 strbuf_addch(msgbuf, '\t');
317                                 strbuf_addstr(msgbuf, ce->name);
318                                 strbuf_addch(msgbuf, '\n');
319                                 while (i < active_nr && !strcmp(ce->name,
320                                                 active_cache[i]->name))
321                                         i++;
322                         }
323                 }
324         }
325
326         return !clean;
327 }
328
329 static int is_index_unchanged(void)
330 {
331         unsigned char head_sha1[20];
332         struct commit *head_commit;
333
334         if (!resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, head_sha1, NULL))
335                 return error(_("Could not resolve HEAD commit\n"));
336
337         head_commit = lookup_commit(head_sha1);
338
339         /*
340          * If head_commit is NULL, check_commit, called from
341          * lookup_commit, would have indicated that head_commit is not
342          * a commit object already.  parse_commit() will return failure
343          * without further complaints in such a case.  Otherwise, if
344          * the commit is invalid, parse_commit() will complain.  So
345          * there is nothing for us to say here.  Just return failure.
346          */
347         if (parse_commit(head_commit))
348                 return -1;
349
350         if (!active_cache_tree)
351                 active_cache_tree = cache_tree();
352
353         if (!cache_tree_fully_valid(active_cache_tree))
354                 if (cache_tree_update(&the_index, 0))
355                         return error(_("Unable to update cache tree\n"));
356
357         return !hashcmp(active_cache_tree->sha1, head_commit->tree->object.sha1);
358 }
359
360 /*
361  * If we are cherry-pick, and if the merge did not result in
362  * hand-editing, we will hit this commit and inherit the original
363  * author date and name.
364  * If we are revert, or if our cherry-pick results in a hand merge,
365  * we had better say that the current user is responsible for that.
366  */
367 static int run_git_commit(const char *defmsg, struct replay_opts *opts,
368                           int allow_empty)
369 {
370         struct argv_array array;
371         int rc;
372
373         argv_array_init(&array);
374         argv_array_push(&array, "commit");
375         argv_array_push(&array, "-n");
376
377         if (opts->gpg_sign)
378                 argv_array_pushf(&array, "-S%s", opts->gpg_sign);
379         if (opts->signoff)
380                 argv_array_push(&array, "-s");
381         if (!opts->edit) {
382                 argv_array_push(&array, "-F");
383                 argv_array_push(&array, defmsg);
384         }
385
386         if (allow_empty)
387                 argv_array_push(&array, "--allow-empty");
388
389         if (opts->allow_empty_message)
390                 argv_array_push(&array, "--allow-empty-message");
391
392         rc = run_command_v_opt(array.argv, RUN_GIT_CMD);
393         argv_array_clear(&array);
394         return rc;
395 }
396
397 static int is_original_commit_empty(struct commit *commit)
398 {
399         const unsigned char *ptree_sha1;
400
401         if (parse_commit(commit))
402                 return error(_("Could not parse commit %s\n"),
403                              sha1_to_hex(commit->object.sha1));
404         if (commit->parents) {
405                 struct commit *parent = commit->parents->item;
406                 if (parse_commit(parent))
407                         return error(_("Could not parse parent commit %s\n"),
408                                 sha1_to_hex(parent->object.sha1));
409                 ptree_sha1 = parent->tree->object.sha1;
410         } else {
411                 ptree_sha1 = EMPTY_TREE_SHA1_BIN; /* commit is root */
412         }
413
414         return !hashcmp(ptree_sha1, commit->tree->object.sha1);
415 }
416
417 /*
418  * Do we run "git commit" with "--allow-empty"?
419  */
420 static int allow_empty(struct replay_opts *opts, struct commit *commit)
421 {
422         int index_unchanged, empty_commit;
423
424         /*
425          * Three cases:
426          *
427          * (1) we do not allow empty at all and error out.
428          *
429          * (2) we allow ones that were initially empty, but
430          * forbid the ones that become empty;
431          *
432          * (3) we allow both.
433          */
434         if (!opts->allow_empty)
435                 return 0; /* let "git commit" barf as necessary */
436
437         index_unchanged = is_index_unchanged();
438         if (index_unchanged < 0)
439                 return index_unchanged;
440         if (!index_unchanged)
441                 return 0; /* we do not have to say --allow-empty */
442
443         if (opts->keep_redundant_commits)
444                 return 1;
445
446         empty_commit = is_original_commit_empty(commit);
447         if (empty_commit < 0)
448                 return empty_commit;
449         if (!empty_commit)
450                 return 0;
451         else
452                 return 1;
453 }
454
455 static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
456 {
457         unsigned char head[20];
458         struct commit *base, *next, *parent;
459         const char *base_label, *next_label;
460         struct commit_message msg = { NULL, NULL, NULL, NULL };
461         char *defmsg = NULL;
462         struct strbuf msgbuf = STRBUF_INIT;
463         int res, unborn = 0, allow;
464
465         if (opts->no_commit) {
466                 /*
467                  * We do not intend to commit immediately.  We just want to
468                  * merge the differences in, so let's compute the tree
469                  * that represents the "current" state for merge-recursive
470                  * to work on.
471                  */
472                 if (write_cache_as_tree(head, 0, NULL))
473                         die (_("Your index file is unmerged."));
474         } else {
475                 unborn = get_sha1("HEAD", head);
476                 if (unborn)
477                         hashcpy(head, EMPTY_TREE_SHA1_BIN);
478                 if (index_differs_from(unborn ? EMPTY_TREE_SHA1_HEX : "HEAD", 0))
479                         return error_dirty_index(opts);
480         }
481         discard_cache();
482
483         if (!commit->parents) {
484                 parent = NULL;
485         }
486         else if (commit->parents->next) {
487                 /* Reverting or cherry-picking a merge commit */
488                 int cnt;
489                 struct commit_list *p;
490
491                 if (!opts->mainline)
492                         return error(_("Commit %s is a merge but no -m option was given."),
493                                 sha1_to_hex(commit->object.sha1));
494
495                 for (cnt = 1, p = commit->parents;
496                      cnt != opts->mainline && p;
497                      cnt++)
498                         p = p->next;
499                 if (cnt != opts->mainline || !p)
500                         return error(_("Commit %s does not have parent %d"),
501                                 sha1_to_hex(commit->object.sha1), opts->mainline);
502                 parent = p->item;
503         } else if (0 < opts->mainline)
504                 return error(_("Mainline was specified but commit %s is not a merge."),
505                         sha1_to_hex(commit->object.sha1));
506         else
507                 parent = commit->parents->item;
508
509         if (opts->allow_ff &&
510             ((parent && !hashcmp(parent->object.sha1, head)) ||
511              (!parent && unborn)))
512                 return fast_forward_to(commit->object.sha1, head, unborn, opts);
513
514         if (parent && parse_commit(parent) < 0)
515                 /* TRANSLATORS: The first %s will be "revert" or
516                    "cherry-pick", the second %s a SHA1 */
517                 return error(_("%s: cannot parse parent commit %s"),
518                         action_name(opts), sha1_to_hex(parent->object.sha1));
519
520         if (get_message(commit, &msg) != 0)
521                 return error(_("Cannot get commit message for %s"),
522                         sha1_to_hex(commit->object.sha1));
523
524         /*
525          * "commit" is an existing commit.  We would want to apply
526          * the difference it introduces since its first parent "prev"
527          * on top of the current HEAD if we are cherry-pick.  Or the
528          * reverse of it if we are revert.
529          */
530
531         defmsg = git_pathdup("MERGE_MSG");
532
533         if (opts->action == REPLAY_REVERT) {
534                 base = commit;
535                 base_label = msg.label;
536                 next = parent;
537                 next_label = msg.parent_label;
538                 strbuf_addstr(&msgbuf, "Revert \"");
539                 strbuf_addstr(&msgbuf, msg.subject);
540                 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
541                 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
542
543                 if (commit->parents && commit->parents->next) {
544                         strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
545                         strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
546                 }
547                 strbuf_addstr(&msgbuf, ".\n");
548         } else {
549                 const char *p;
550
551                 base = parent;
552                 base_label = msg.parent_label;
553                 next = commit;
554                 next_label = msg.label;
555
556                 /*
557                  * Append the commit log message to msgbuf; it starts
558                  * after the tree, parent, author, committer
559                  * information followed by "\n\n".
560                  */
561                 p = strstr(msg.message, "\n\n");
562                 if (p) {
563                         p += 2;
564                         strbuf_addstr(&msgbuf, p);
565                 }
566
567                 if (opts->record_origin) {
568                         if (!has_conforming_footer(&msgbuf, NULL, 0))
569                                 strbuf_addch(&msgbuf, '\n');
570                         strbuf_addstr(&msgbuf, cherry_picked_prefix);
571                         strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
572                         strbuf_addstr(&msgbuf, ")\n");
573                 }
574         }
575
576         if (!opts->strategy || !strcmp(opts->strategy, "recursive") || opts->action == REPLAY_REVERT) {
577                 res = do_recursive_merge(base, next, base_label, next_label,
578                                          head, &msgbuf, opts);
579                 write_message(&msgbuf, defmsg);
580         } else {
581                 struct commit_list *common = NULL;
582                 struct commit_list *remotes = NULL;
583
584                 write_message(&msgbuf, defmsg);
585
586                 commit_list_insert(base, &common);
587                 commit_list_insert(next, &remotes);
588                 res = try_merge_command(opts->strategy, opts->xopts_nr, opts->xopts,
589                                         common, sha1_to_hex(head), remotes);
590                 free_commit_list(common);
591                 free_commit_list(remotes);
592         }
593
594         /*
595          * If the merge was clean or if it failed due to conflict, we write
596          * CHERRY_PICK_HEAD for the subsequent invocation of commit to use.
597          * However, if the merge did not even start, then we don't want to
598          * write it at all.
599          */
600         if (opts->action == REPLAY_PICK && !opts->no_commit && (res == 0 || res == 1))
601                 write_cherry_pick_head(commit, "CHERRY_PICK_HEAD");
602         if (opts->action == REPLAY_REVERT && ((opts->no_commit && res == 0) || res == 1))
603                 write_cherry_pick_head(commit, "REVERT_HEAD");
604
605         if (res) {
606                 error(opts->action == REPLAY_REVERT
607                       ? _("could not revert %s... %s")
608                       : _("could not apply %s... %s"),
609                       find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV),
610                       msg.subject);
611                 print_advice(res == 1, opts);
612                 rerere(opts->allow_rerere_auto);
613                 goto leave;
614         }
615
616         allow = allow_empty(opts, commit);
617         if (allow < 0) {
618                 res = allow;
619                 goto leave;
620         }
621         if (!opts->no_commit)
622                 res = run_git_commit(defmsg, opts, allow);
623
624 leave:
625         free_message(commit, &msg);
626         free(defmsg);
627
628         return res;
629 }
630
631 static void prepare_revs(struct replay_opts *opts)
632 {
633         /*
634          * picking (but not reverting) ranges (but not individual revisions)
635          * should be done in reverse
636          */
637         if (opts->action == REPLAY_PICK && !opts->revs->no_walk)
638                 opts->revs->reverse ^= 1;
639
640         if (prepare_revision_walk(opts->revs))
641                 die(_("revision walk setup failed"));
642
643         if (!opts->revs->commits)
644                 die(_("empty commit set passed"));
645 }
646
647 static void read_and_refresh_cache(struct replay_opts *opts)
648 {
649         static struct lock_file index_lock;
650         int index_fd = hold_locked_index(&index_lock, 0);
651         if (read_index_preload(&the_index, NULL) < 0)
652                 die(_("git %s: failed to read the index"), action_name(opts));
653         refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
654         if (the_index.cache_changed && index_fd >= 0) {
655                 if (write_locked_index(&the_index, &index_lock, COMMIT_LOCK))
656                         die(_("git %s: failed to refresh the index"), action_name(opts));
657         }
658         rollback_lock_file(&index_lock);
659 }
660
661 static int format_todo(struct strbuf *buf, struct commit_list *todo_list,
662                 struct replay_opts *opts)
663 {
664         struct commit_list *cur = NULL;
665         const char *sha1_abbrev = NULL;
666         const char *action_str = opts->action == REPLAY_REVERT ? "revert" : "pick";
667         const char *subject;
668         int subject_len;
669
670         for (cur = todo_list; cur; cur = cur->next) {
671                 const char *commit_buffer = get_commit_buffer(cur->item, NULL);
672                 sha1_abbrev = find_unique_abbrev(cur->item->object.sha1, DEFAULT_ABBREV);
673                 subject_len = find_commit_subject(commit_buffer, &subject);
674                 strbuf_addf(buf, "%s %s %.*s\n", action_str, sha1_abbrev,
675                         subject_len, subject);
676                 unuse_commit_buffer(cur->item, commit_buffer);
677         }
678         return 0;
679 }
680
681 static struct commit *parse_insn_line(char *bol, char *eol, struct replay_opts *opts)
682 {
683         unsigned char commit_sha1[20];
684         enum replay_action action;
685         char *end_of_object_name;
686         int saved, status, padding;
687
688         if (starts_with(bol, "pick")) {
689                 action = REPLAY_PICK;
690                 bol += strlen("pick");
691         } else if (starts_with(bol, "revert")) {
692                 action = REPLAY_REVERT;
693                 bol += strlen("revert");
694         } else
695                 return NULL;
696
697         /* Eat up extra spaces/ tabs before object name */
698         padding = strspn(bol, " \t");
699         if (!padding)
700                 return NULL;
701         bol += padding;
702
703         end_of_object_name = bol + strcspn(bol, " \t\n");
704         saved = *end_of_object_name;
705         *end_of_object_name = '\0';
706         status = get_sha1(bol, commit_sha1);
707         *end_of_object_name = saved;
708
709         /*
710          * Verify that the action matches up with the one in
711          * opts; we don't support arbitrary instructions
712          */
713         if (action != opts->action) {
714                 const char *action_str;
715                 action_str = action == REPLAY_REVERT ? "revert" : "cherry-pick";
716                 error(_("Cannot %s during a %s"), action_str, action_name(opts));
717                 return NULL;
718         }
719
720         if (status < 0)
721                 return NULL;
722
723         return lookup_commit_reference(commit_sha1);
724 }
725
726 static int parse_insn_buffer(char *buf, struct commit_list **todo_list,
727                         struct replay_opts *opts)
728 {
729         struct commit_list **next = todo_list;
730         struct commit *commit;
731         char *p = buf;
732         int i;
733
734         for (i = 1; *p; i++) {
735                 char *eol = strchrnul(p, '\n');
736                 commit = parse_insn_line(p, eol, opts);
737                 if (!commit)
738                         return error(_("Could not parse line %d."), i);
739                 next = commit_list_append(commit, next);
740                 p = *eol ? eol + 1 : eol;
741         }
742         if (!*todo_list)
743                 return error(_("No commits parsed."));
744         return 0;
745 }
746
747 static void read_populate_todo(struct commit_list **todo_list,
748                         struct replay_opts *opts)
749 {
750         const char *todo_file = git_path(SEQ_TODO_FILE);
751         struct strbuf buf = STRBUF_INIT;
752         int fd, res;
753
754         fd = open(todo_file, O_RDONLY);
755         if (fd < 0)
756                 die_errno(_("Could not open %s"), todo_file);
757         if (strbuf_read(&buf, fd, 0) < 0) {
758                 close(fd);
759                 strbuf_release(&buf);
760                 die(_("Could not read %s."), todo_file);
761         }
762         close(fd);
763
764         res = parse_insn_buffer(buf.buf, todo_list, opts);
765         strbuf_release(&buf);
766         if (res)
767                 die(_("Unusable instruction sheet: %s"), todo_file);
768 }
769
770 static int populate_opts_cb(const char *key, const char *value, void *data)
771 {
772         struct replay_opts *opts = data;
773         int error_flag = 1;
774
775         if (!value)
776                 error_flag = 0;
777         else if (!strcmp(key, "options.no-commit"))
778                 opts->no_commit = git_config_bool_or_int(key, value, &error_flag);
779         else if (!strcmp(key, "options.edit"))
780                 opts->edit = git_config_bool_or_int(key, value, &error_flag);
781         else if (!strcmp(key, "options.signoff"))
782                 opts->signoff = git_config_bool_or_int(key, value, &error_flag);
783         else if (!strcmp(key, "options.record-origin"))
784                 opts->record_origin = git_config_bool_or_int(key, value, &error_flag);
785         else if (!strcmp(key, "options.allow-ff"))
786                 opts->allow_ff = git_config_bool_or_int(key, value, &error_flag);
787         else if (!strcmp(key, "options.mainline"))
788                 opts->mainline = git_config_int(key, value);
789         else if (!strcmp(key, "options.strategy"))
790                 git_config_string(&opts->strategy, key, value);
791         else if (!strcmp(key, "options.gpg-sign"))
792                 git_config_string(&opts->gpg_sign, key, value);
793         else if (!strcmp(key, "options.strategy-option")) {
794                 ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
795                 opts->xopts[opts->xopts_nr++] = xstrdup(value);
796         } else
797                 return error(_("Invalid key: %s"), key);
798
799         if (!error_flag)
800                 return error(_("Invalid value for %s: %s"), key, value);
801
802         return 0;
803 }
804
805 static void read_populate_opts(struct replay_opts **opts_ptr)
806 {
807         const char *opts_file = git_path(SEQ_OPTS_FILE);
808
809         if (!file_exists(opts_file))
810                 return;
811         if (git_config_from_file(populate_opts_cb, opts_file, *opts_ptr) < 0)
812                 die(_("Malformed options sheet: %s"), opts_file);
813 }
814
815 static void walk_revs_populate_todo(struct commit_list **todo_list,
816                                 struct replay_opts *opts)
817 {
818         struct commit *commit;
819         struct commit_list **next;
820
821         prepare_revs(opts);
822
823         next = todo_list;
824         while ((commit = get_revision(opts->revs)))
825                 next = commit_list_append(commit, next);
826 }
827
828 static int create_seq_dir(void)
829 {
830         const char *seq_dir = git_path(SEQ_DIR);
831
832         if (file_exists(seq_dir)) {
833                 error(_("a cherry-pick or revert is already in progress"));
834                 advise(_("try \"git cherry-pick (--continue | --quit | --abort)\""));
835                 return -1;
836         }
837         else if (mkdir(seq_dir, 0777) < 0)
838                 die_errno(_("Could not create sequencer directory %s"), seq_dir);
839         return 0;
840 }
841
842 static void save_head(const char *head)
843 {
844         const char *head_file = git_path(SEQ_HEAD_FILE);
845         static struct lock_file head_lock;
846         struct strbuf buf = STRBUF_INIT;
847         int fd;
848
849         fd = hold_lock_file_for_update(&head_lock, head_file, LOCK_DIE_ON_ERROR);
850         strbuf_addf(&buf, "%s\n", head);
851         if (write_in_full(fd, buf.buf, buf.len) < 0)
852                 die_errno(_("Could not write to %s"), head_file);
853         if (commit_lock_file(&head_lock) < 0)
854                 die(_("Error wrapping up %s."), head_file);
855 }
856
857 static int reset_for_rollback(const unsigned char *sha1)
858 {
859         const char *argv[4];    /* reset --merge <arg> + NULL */
860         argv[0] = "reset";
861         argv[1] = "--merge";
862         argv[2] = sha1_to_hex(sha1);
863         argv[3] = NULL;
864         return run_command_v_opt(argv, RUN_GIT_CMD);
865 }
866
867 static int rollback_single_pick(void)
868 {
869         unsigned char head_sha1[20];
870
871         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
872             !file_exists(git_path("REVERT_HEAD")))
873                 return error(_("no cherry-pick or revert in progress"));
874         if (read_ref_full("HEAD", 0, head_sha1, NULL))
875                 return error(_("cannot resolve HEAD"));
876         if (is_null_sha1(head_sha1))
877                 return error(_("cannot abort from a branch yet to be born"));
878         return reset_for_rollback(head_sha1);
879 }
880
881 static int sequencer_rollback(struct replay_opts *opts)
882 {
883         const char *filename;
884         FILE *f;
885         unsigned char sha1[20];
886         struct strbuf buf = STRBUF_INIT;
887
888         filename = git_path(SEQ_HEAD_FILE);
889         f = fopen(filename, "r");
890         if (!f && errno == ENOENT) {
891                 /*
892                  * There is no multiple-cherry-pick in progress.
893                  * If CHERRY_PICK_HEAD or REVERT_HEAD indicates
894                  * a single-cherry-pick in progress, abort that.
895                  */
896                 return rollback_single_pick();
897         }
898         if (!f)
899                 return error(_("cannot open %s: %s"), filename,
900                                                 strerror(errno));
901         if (strbuf_getline(&buf, f, '\n')) {
902                 error(_("cannot read %s: %s"), filename, ferror(f) ?
903                         strerror(errno) : _("unexpected end of file"));
904                 fclose(f);
905                 goto fail;
906         }
907         fclose(f);
908         if (get_sha1_hex(buf.buf, sha1) || buf.buf[40] != '\0') {
909                 error(_("stored pre-cherry-pick HEAD file '%s' is corrupt"),
910                         filename);
911                 goto fail;
912         }
913         if (reset_for_rollback(sha1))
914                 goto fail;
915         remove_sequencer_state();
916         strbuf_release(&buf);
917         return 0;
918 fail:
919         strbuf_release(&buf);
920         return -1;
921 }
922
923 static void save_todo(struct commit_list *todo_list, struct replay_opts *opts)
924 {
925         const char *todo_file = git_path(SEQ_TODO_FILE);
926         static struct lock_file todo_lock;
927         struct strbuf buf = STRBUF_INIT;
928         int fd;
929
930         fd = hold_lock_file_for_update(&todo_lock, todo_file, LOCK_DIE_ON_ERROR);
931         if (format_todo(&buf, todo_list, opts) < 0)
932                 die(_("Could not format %s."), todo_file);
933         if (write_in_full(fd, buf.buf, buf.len) < 0) {
934                 strbuf_release(&buf);
935                 die_errno(_("Could not write to %s"), todo_file);
936         }
937         if (commit_lock_file(&todo_lock) < 0) {
938                 strbuf_release(&buf);
939                 die(_("Error wrapping up %s."), todo_file);
940         }
941         strbuf_release(&buf);
942 }
943
944 static void save_opts(struct replay_opts *opts)
945 {
946         const char *opts_file = git_path(SEQ_OPTS_FILE);
947
948         if (opts->no_commit)
949                 git_config_set_in_file(opts_file, "options.no-commit", "true");
950         if (opts->edit)
951                 git_config_set_in_file(opts_file, "options.edit", "true");
952         if (opts->signoff)
953                 git_config_set_in_file(opts_file, "options.signoff", "true");
954         if (opts->record_origin)
955                 git_config_set_in_file(opts_file, "options.record-origin", "true");
956         if (opts->allow_ff)
957                 git_config_set_in_file(opts_file, "options.allow-ff", "true");
958         if (opts->mainline) {
959                 struct strbuf buf = STRBUF_INIT;
960                 strbuf_addf(&buf, "%d", opts->mainline);
961                 git_config_set_in_file(opts_file, "options.mainline", buf.buf);
962                 strbuf_release(&buf);
963         }
964         if (opts->strategy)
965                 git_config_set_in_file(opts_file, "options.strategy", opts->strategy);
966         if (opts->gpg_sign)
967                 git_config_set_in_file(opts_file, "options.gpg-sign", opts->gpg_sign);
968         if (opts->xopts) {
969                 int i;
970                 for (i = 0; i < opts->xopts_nr; i++)
971                         git_config_set_multivar_in_file(opts_file,
972                                                         "options.strategy-option",
973                                                         opts->xopts[i], "^$", 0);
974         }
975 }
976
977 static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
978 {
979         struct commit_list *cur;
980         int res;
981
982         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
983         if (opts->allow_ff)
984                 assert(!(opts->signoff || opts->no_commit ||
985                                 opts->record_origin || opts->edit));
986         read_and_refresh_cache(opts);
987
988         for (cur = todo_list; cur; cur = cur->next) {
989                 save_todo(cur, opts);
990                 res = do_pick_commit(cur->item, opts);
991                 if (res)
992                         return res;
993         }
994
995         /*
996          * Sequence of picks finished successfully; cleanup by
997          * removing the .git/sequencer directory
998          */
999         remove_sequencer_state();
1000         return 0;
1001 }
1002
1003 static int continue_single_pick(void)
1004 {
1005         const char *argv[] = { "commit", NULL };
1006
1007         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
1008             !file_exists(git_path("REVERT_HEAD")))
1009                 return error(_("no cherry-pick or revert in progress"));
1010         return run_command_v_opt(argv, RUN_GIT_CMD);
1011 }
1012
1013 static int sequencer_continue(struct replay_opts *opts)
1014 {
1015         struct commit_list *todo_list = NULL;
1016
1017         if (!file_exists(git_path(SEQ_TODO_FILE)))
1018                 return continue_single_pick();
1019         read_populate_opts(&opts);
1020         read_populate_todo(&todo_list, opts);
1021
1022         /* Verify that the conflict has been resolved */
1023         if (file_exists(git_path("CHERRY_PICK_HEAD")) ||
1024             file_exists(git_path("REVERT_HEAD"))) {
1025                 int ret = continue_single_pick();
1026                 if (ret)
1027                         return ret;
1028         }
1029         if (index_differs_from("HEAD", 0))
1030                 return error_dirty_index(opts);
1031         todo_list = todo_list->next;
1032         return pick_commits(todo_list, opts);
1033 }
1034
1035 static int single_pick(struct commit *cmit, struct replay_opts *opts)
1036 {
1037         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
1038         return do_pick_commit(cmit, opts);
1039 }
1040
1041 int sequencer_pick_revisions(struct replay_opts *opts)
1042 {
1043         struct commit_list *todo_list = NULL;
1044         unsigned char sha1[20];
1045         int i;
1046
1047         if (opts->subcommand == REPLAY_NONE)
1048                 assert(opts->revs);
1049
1050         read_and_refresh_cache(opts);
1051
1052         /*
1053          * Decide what to do depending on the arguments; a fresh
1054          * cherry-pick should be handled differently from an existing
1055          * one that is being continued
1056          */
1057         if (opts->subcommand == REPLAY_REMOVE_STATE) {
1058                 remove_sequencer_state();
1059                 return 0;
1060         }
1061         if (opts->subcommand == REPLAY_ROLLBACK)
1062                 return sequencer_rollback(opts);
1063         if (opts->subcommand == REPLAY_CONTINUE)
1064                 return sequencer_continue(opts);
1065
1066         for (i = 0; i < opts->revs->pending.nr; i++) {
1067                 unsigned char sha1[20];
1068                 const char *name = opts->revs->pending.objects[i].name;
1069
1070                 /* This happens when using --stdin. */
1071                 if (!strlen(name))
1072                         continue;
1073
1074                 if (!get_sha1(name, sha1)) {
1075                         if (!lookup_commit_reference_gently(sha1, 1)) {
1076                                 enum object_type type = sha1_object_info(sha1, NULL);
1077                                 die(_("%s: can't cherry-pick a %s"), name, typename(type));
1078                         }
1079                 } else
1080                         die(_("%s: bad revision"), name);
1081         }
1082
1083         /*
1084          * If we were called as "git cherry-pick <commit>", just
1085          * cherry-pick/revert it, set CHERRY_PICK_HEAD /
1086          * REVERT_HEAD, and don't touch the sequencer state.
1087          * This means it is possible to cherry-pick in the middle
1088          * of a cherry-pick sequence.
1089          */
1090         if (opts->revs->cmdline.nr == 1 &&
1091             opts->revs->cmdline.rev->whence == REV_CMD_REV &&
1092             opts->revs->no_walk &&
1093             !opts->revs->cmdline.rev->flags) {
1094                 struct commit *cmit;
1095                 if (prepare_revision_walk(opts->revs))
1096                         die(_("revision walk setup failed"));
1097                 cmit = get_revision(opts->revs);
1098                 if (!cmit || get_revision(opts->revs))
1099                         die("BUG: expected exactly one commit from walk");
1100                 return single_pick(cmit, opts);
1101         }
1102
1103         /*
1104          * Start a new cherry-pick/ revert sequence; but
1105          * first, make sure that an existing one isn't in
1106          * progress
1107          */
1108
1109         walk_revs_populate_todo(&todo_list, opts);
1110         if (create_seq_dir() < 0)
1111                 return -1;
1112         if (get_sha1("HEAD", sha1)) {
1113                 if (opts->action == REPLAY_REVERT)
1114                         return error(_("Can't revert as initial commit"));
1115                 return error(_("Can't cherry-pick into empty head"));
1116         }
1117         save_head(sha1_to_hex(sha1));
1118         save_opts(opts);
1119         return pick_commits(todo_list, opts);
1120 }
1121
1122 void append_signoff(struct strbuf *msgbuf, int ignore_footer, unsigned flag)
1123 {
1124         unsigned no_dup_sob = flag & APPEND_SIGNOFF_DEDUP;
1125         struct strbuf sob = STRBUF_INIT;
1126         int has_footer;
1127
1128         strbuf_addstr(&sob, sign_off_header);
1129         strbuf_addstr(&sob, fmt_name(getenv("GIT_COMMITTER_NAME"),
1130                                 getenv("GIT_COMMITTER_EMAIL")));
1131         strbuf_addch(&sob, '\n');
1132
1133         /*
1134          * If the whole message buffer is equal to the sob, pretend that we
1135          * found a conforming footer with a matching sob
1136          */
1137         if (msgbuf->len - ignore_footer == sob.len &&
1138             !strncmp(msgbuf->buf, sob.buf, sob.len))
1139                 has_footer = 3;
1140         else
1141                 has_footer = has_conforming_footer(msgbuf, &sob, ignore_footer);
1142
1143         if (!has_footer) {
1144                 const char *append_newlines = NULL;
1145                 size_t len = msgbuf->len - ignore_footer;
1146
1147                 if (!len) {
1148                         /*
1149                          * The buffer is completely empty.  Leave foom for
1150                          * the title and body to be filled in by the user.
1151                          */
1152                         append_newlines = "\n\n";
1153                 } else if (msgbuf->buf[len - 1] != '\n') {
1154                         /*
1155                          * Incomplete line.  Complete the line and add a
1156                          * blank one so that there is an empty line between
1157                          * the message body and the sob.
1158                          */
1159                         append_newlines = "\n\n";
1160                 } else if (len == 1) {
1161                         /*
1162                          * Buffer contains a single newline.  Add another
1163                          * so that we leave room for the title and body.
1164                          */
1165                         append_newlines = "\n";
1166                 } else if (msgbuf->buf[len - 2] != '\n') {
1167                         /*
1168                          * Buffer ends with a single newline.  Add another
1169                          * so that there is an empty line between the message
1170                          * body and the sob.
1171                          */
1172                         append_newlines = "\n";
1173                 } /* else, the buffer already ends with two newlines. */
1174
1175                 if (append_newlines)
1176                         strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0,
1177                                 append_newlines, strlen(append_newlines));
1178         }
1179
1180         if (has_footer != 3 && (!no_dup_sob || has_footer != 2))
1181                 strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0,
1182                                 sob.buf, sob.len);
1183
1184         strbuf_release(&sob);
1185 }