t7201.24: Add refspec to keep --track working
[git] / sequencer.c
1 #include "cache.h"
2 #include "sequencer.h"
3 #include "dir.h"
4 #include "object.h"
5 #include "commit.h"
6 #include "tag.h"
7 #include "run-command.h"
8 #include "exec_cmd.h"
9 #include "utf8.h"
10 #include "cache-tree.h"
11 #include "diff.h"
12 #include "revision.h"
13 #include "rerere.h"
14 #include "merge-recursive.h"
15 #include "refs.h"
16 #include "argv-array.h"
17
18 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
19
20 const char sign_off_header[] = "Signed-off-by: ";
21 static const char cherry_picked_prefix[] = "(cherry picked from commit ";
22
23 static int is_rfc2822_line(const char *buf, int len)
24 {
25         int i;
26
27         for (i = 0; i < len; i++) {
28                 int ch = buf[i];
29                 if (ch == ':')
30                         return 1;
31                 if (!isalnum(ch) && ch != '-')
32                         break;
33         }
34
35         return 0;
36 }
37
38 static int is_cherry_picked_from_line(const char *buf, int len)
39 {
40         /*
41          * We only care that it looks roughly like (cherry picked from ...)
42          */
43         return len > strlen(cherry_picked_prefix) + 1 &&
44                 !prefixcmp(buf, cherry_picked_prefix) && buf[len - 1] == ')';
45 }
46
47 /*
48  * Returns 0 for non-conforming footer
49  * Returns 1 for conforming footer
50  * Returns 2 when sob exists within conforming footer
51  * Returns 3 when sob exists within conforming footer as last entry
52  */
53 static int has_conforming_footer(struct strbuf *sb, struct strbuf *sob,
54         int ignore_footer)
55 {
56         char prev;
57         int i, k;
58         int len = sb->len - ignore_footer;
59         const char *buf = sb->buf;
60         int found_sob = 0;
61
62         /* footer must end with newline */
63         if (!len || buf[len - 1] != '\n')
64                 return 0;
65
66         prev = '\0';
67         for (i = len - 1; i > 0; i--) {
68                 char ch = buf[i];
69                 if (prev == '\n' && ch == '\n') /* paragraph break */
70                         break;
71                 prev = ch;
72         }
73
74         /* require at least one blank line */
75         if (prev != '\n' || buf[i] != '\n')
76                 return 0;
77
78         /* advance to start of last paragraph */
79         while (i < len - 1 && buf[i] == '\n')
80                 i++;
81
82         for (; i < len; i = k) {
83                 int found_rfc2822;
84
85                 for (k = i; k < len && buf[k] != '\n'; k++)
86                         ; /* do nothing */
87                 k++;
88
89                 found_rfc2822 = is_rfc2822_line(buf + i, k - i - 1);
90                 if (found_rfc2822 && sob &&
91                     !strncmp(buf + i, sob->buf, sob->len))
92                         found_sob = k;
93
94                 if (!(found_rfc2822 ||
95                       is_cherry_picked_from_line(buf + i, k - i - 1)))
96                         return 0;
97         }
98         if (found_sob == i)
99                 return 3;
100         if (found_sob)
101                 return 2;
102         return 1;
103 }
104
105 static void remove_sequencer_state(void)
106 {
107         struct strbuf seq_dir = STRBUF_INIT;
108
109         strbuf_addf(&seq_dir, "%s", git_path(SEQ_DIR));
110         remove_dir_recursively(&seq_dir, 0);
111         strbuf_release(&seq_dir);
112 }
113
114 static const char *action_name(const struct replay_opts *opts)
115 {
116         return opts->action == REPLAY_REVERT ? "revert" : "cherry-pick";
117 }
118
119 static char *get_encoding(const char *message);
120
121 struct commit_message {
122         char *parent_label;
123         const char *label;
124         const char *subject;
125         char *reencoded_message;
126         const char *message;
127 };
128
129 static int get_message(struct commit *commit, struct commit_message *out)
130 {
131         const char *encoding;
132         const char *abbrev, *subject;
133         int abbrev_len, subject_len;
134         char *q;
135
136         if (!commit->buffer)
137                 return -1;
138         encoding = get_encoding(commit->buffer);
139         if (!encoding)
140                 encoding = "UTF-8";
141         if (!git_commit_encoding)
142                 git_commit_encoding = "UTF-8";
143
144         out->reencoded_message = NULL;
145         out->message = commit->buffer;
146         if (same_encoding(encoding, git_commit_encoding))
147                 out->reencoded_message = reencode_string(commit->buffer,
148                                         git_commit_encoding, encoding);
149         if (out->reencoded_message)
150                 out->message = out->reencoded_message;
151
152         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
153         abbrev_len = strlen(abbrev);
154
155         subject_len = find_commit_subject(out->message, &subject);
156
157         out->parent_label = xmalloc(strlen("parent of ") + abbrev_len +
158                               strlen("... ") + subject_len + 1);
159         q = out->parent_label;
160         q = mempcpy(q, "parent of ", strlen("parent of "));
161         out->label = q;
162         q = mempcpy(q, abbrev, abbrev_len);
163         q = mempcpy(q, "... ", strlen("... "));
164         out->subject = q;
165         q = mempcpy(q, subject, subject_len);
166         *q = '\0';
167         return 0;
168 }
169
170 static void free_message(struct commit_message *msg)
171 {
172         free(msg->parent_label);
173         free(msg->reencoded_message);
174 }
175
176 static char *get_encoding(const char *message)
177 {
178         const char *p = message, *eol;
179
180         while (*p && *p != '\n') {
181                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
182                         ; /* do nothing */
183                 if (!prefixcmp(p, "encoding ")) {
184                         char *result = xmalloc(eol - 8 - p);
185                         strlcpy(result, p + 9, eol - 8 - p);
186                         return result;
187                 }
188                 p = eol;
189                 if (*p == '\n')
190                         p++;
191         }
192         return NULL;
193 }
194
195 static void write_cherry_pick_head(struct commit *commit, const char *pseudoref)
196 {
197         const char *filename;
198         int fd;
199         struct strbuf buf = STRBUF_INIT;
200
201         strbuf_addf(&buf, "%s\n", sha1_to_hex(commit->object.sha1));
202
203         filename = git_path("%s", pseudoref);
204         fd = open(filename, O_WRONLY | O_CREAT, 0666);
205         if (fd < 0)
206                 die_errno(_("Could not open '%s' for writing"), filename);
207         if (write_in_full(fd, buf.buf, buf.len) != buf.len || close(fd))
208                 die_errno(_("Could not write to '%s'"), filename);
209         strbuf_release(&buf);
210 }
211
212 static void print_advice(int show_hint, struct replay_opts *opts)
213 {
214         char *msg = getenv("GIT_CHERRY_PICK_HELP");
215
216         if (msg) {
217                 fprintf(stderr, "%s\n", msg);
218                 /*
219                  * A conflict has occurred but the porcelain
220                  * (typically rebase --interactive) wants to take care
221                  * of the commit itself so remove CHERRY_PICK_HEAD
222                  */
223                 unlink(git_path("CHERRY_PICK_HEAD"));
224                 return;
225         }
226
227         if (show_hint) {
228                 if (opts->no_commit)
229                         advise(_("after resolving the conflicts, mark the corrected paths\n"
230                                  "with 'git add <paths>' or 'git rm <paths>'"));
231                 else
232                         advise(_("after resolving the conflicts, mark the corrected paths\n"
233                                  "with 'git add <paths>' or 'git rm <paths>'\n"
234                                  "and commit the result with 'git commit'"));
235         }
236 }
237
238 static void write_message(struct strbuf *msgbuf, const char *filename)
239 {
240         static struct lock_file msg_file;
241
242         int msg_fd = hold_lock_file_for_update(&msg_file, filename,
243                                                LOCK_DIE_ON_ERROR);
244         if (write_in_full(msg_fd, msgbuf->buf, msgbuf->len) < 0)
245                 die_errno(_("Could not write to %s"), filename);
246         strbuf_release(msgbuf);
247         if (commit_lock_file(&msg_file) < 0)
248                 die(_("Error wrapping up %s"), filename);
249 }
250
251 static struct tree *empty_tree(void)
252 {
253         return lookup_tree(EMPTY_TREE_SHA1_BIN);
254 }
255
256 static int error_dirty_index(struct replay_opts *opts)
257 {
258         if (read_cache_unmerged())
259                 return error_resolve_conflict(action_name(opts));
260
261         /* Different translation strings for cherry-pick and revert */
262         if (opts->action == REPLAY_PICK)
263                 error(_("Your local changes would be overwritten by cherry-pick."));
264         else
265                 error(_("Your local changes would be overwritten by revert."));
266
267         if (advice_commit_before_merge)
268                 advise(_("Commit your changes or stash them to proceed."));
269         return -1;
270 }
271
272 static int fast_forward_to(const unsigned char *to, const unsigned char *from,
273                            int unborn)
274 {
275         struct ref_lock *ref_lock;
276
277         read_cache();
278         if (checkout_fast_forward(from, to, 1))
279                 exit(1); /* the callee should have complained already */
280         ref_lock = lock_any_ref_for_update("HEAD", unborn ? null_sha1 : from, 0);
281         return write_ref_sha1(ref_lock, to, "cherry-pick");
282 }
283
284 static int do_recursive_merge(struct commit *base, struct commit *next,
285                               const char *base_label, const char *next_label,
286                               unsigned char *head, struct strbuf *msgbuf,
287                               struct replay_opts *opts)
288 {
289         struct merge_options o;
290         struct tree *result, *next_tree, *base_tree, *head_tree;
291         int clean, index_fd;
292         const char **xopt;
293         static struct lock_file index_lock;
294
295         index_fd = hold_locked_index(&index_lock, 1);
296
297         read_cache();
298
299         init_merge_options(&o);
300         o.ancestor = base ? base_label : "(empty tree)";
301         o.branch1 = "HEAD";
302         o.branch2 = next ? next_label : "(empty tree)";
303
304         head_tree = parse_tree_indirect(head);
305         next_tree = next ? next->tree : empty_tree();
306         base_tree = base ? base->tree : empty_tree();
307
308         for (xopt = opts->xopts; xopt != opts->xopts + opts->xopts_nr; xopt++)
309                 parse_merge_opt(&o, *xopt);
310
311         clean = merge_trees(&o,
312                             head_tree,
313                             next_tree, base_tree, &result);
314
315         if (active_cache_changed &&
316             (write_cache(index_fd, active_cache, active_nr) ||
317              commit_locked_index(&index_lock)))
318                 /* TRANSLATORS: %s will be "revert" or "cherry-pick" */
319                 die(_("%s: Unable to write new index file"), action_name(opts));
320         rollback_lock_file(&index_lock);
321
322         if (opts->signoff)
323                 append_signoff(msgbuf, 0, 0);
324
325         if (!clean) {
326                 int i;
327                 strbuf_addstr(msgbuf, "\nConflicts:\n");
328                 for (i = 0; i < active_nr;) {
329                         struct cache_entry *ce = active_cache[i++];
330                         if (ce_stage(ce)) {
331                                 strbuf_addch(msgbuf, '\t');
332                                 strbuf_addstr(msgbuf, ce->name);
333                                 strbuf_addch(msgbuf, '\n');
334                                 while (i < active_nr && !strcmp(ce->name,
335                                                 active_cache[i]->name))
336                                         i++;
337                         }
338                 }
339         }
340
341         return !clean;
342 }
343
344 static int is_index_unchanged(void)
345 {
346         unsigned char head_sha1[20];
347         struct commit *head_commit;
348
349         if (!resolve_ref_unsafe("HEAD", head_sha1, 1, NULL))
350                 return error(_("Could not resolve HEAD commit\n"));
351
352         head_commit = lookup_commit(head_sha1);
353
354         /*
355          * If head_commit is NULL, check_commit, called from
356          * lookup_commit, would have indicated that head_commit is not
357          * a commit object already.  parse_commit() will return failure
358          * without further complaints in such a case.  Otherwise, if
359          * the commit is invalid, parse_commit() will complain.  So
360          * there is nothing for us to say here.  Just return failure.
361          */
362         if (parse_commit(head_commit))
363                 return -1;
364
365         if (!active_cache_tree)
366                 active_cache_tree = cache_tree();
367
368         if (!cache_tree_fully_valid(active_cache_tree))
369                 if (cache_tree_update(active_cache_tree, active_cache,
370                                   active_nr, 0))
371                         return error(_("Unable to update cache tree\n"));
372
373         return !hashcmp(active_cache_tree->sha1, head_commit->tree->object.sha1);
374 }
375
376 /*
377  * If we are cherry-pick, and if the merge did not result in
378  * hand-editing, we will hit this commit and inherit the original
379  * author date and name.
380  * If we are revert, or if our cherry-pick results in a hand merge,
381  * we had better say that the current user is responsible for that.
382  */
383 static int run_git_commit(const char *defmsg, struct replay_opts *opts,
384                           int allow_empty)
385 {
386         struct argv_array array;
387         int rc;
388
389         argv_array_init(&array);
390         argv_array_push(&array, "commit");
391         argv_array_push(&array, "-n");
392
393         if (opts->signoff)
394                 argv_array_push(&array, "-s");
395         if (!opts->edit) {
396                 argv_array_push(&array, "-F");
397                 argv_array_push(&array, defmsg);
398         }
399
400         if (allow_empty)
401                 argv_array_push(&array, "--allow-empty");
402
403         if (opts->allow_empty_message)
404                 argv_array_push(&array, "--allow-empty-message");
405
406         rc = run_command_v_opt(array.argv, RUN_GIT_CMD);
407         argv_array_clear(&array);
408         return rc;
409 }
410
411 static int is_original_commit_empty(struct commit *commit)
412 {
413         const unsigned char *ptree_sha1;
414
415         if (parse_commit(commit))
416                 return error(_("Could not parse commit %s\n"),
417                              sha1_to_hex(commit->object.sha1));
418         if (commit->parents) {
419                 struct commit *parent = commit->parents->item;
420                 if (parse_commit(parent))
421                         return error(_("Could not parse parent commit %s\n"),
422                                 sha1_to_hex(parent->object.sha1));
423                 ptree_sha1 = parent->tree->object.sha1;
424         } else {
425                 ptree_sha1 = EMPTY_TREE_SHA1_BIN; /* commit is root */
426         }
427
428         return !hashcmp(ptree_sha1, commit->tree->object.sha1);
429 }
430
431 /*
432  * Do we run "git commit" with "--allow-empty"?
433  */
434 static int allow_empty(struct replay_opts *opts, struct commit *commit)
435 {
436         int index_unchanged, empty_commit;
437
438         /*
439          * Three cases:
440          *
441          * (1) we do not allow empty at all and error out.
442          *
443          * (2) we allow ones that were initially empty, but
444          * forbid the ones that become empty;
445          *
446          * (3) we allow both.
447          */
448         if (!opts->allow_empty)
449                 return 0; /* let "git commit" barf as necessary */
450
451         index_unchanged = is_index_unchanged();
452         if (index_unchanged < 0)
453                 return index_unchanged;
454         if (!index_unchanged)
455                 return 0; /* we do not have to say --allow-empty */
456
457         if (opts->keep_redundant_commits)
458                 return 1;
459
460         empty_commit = is_original_commit_empty(commit);
461         if (empty_commit < 0)
462                 return empty_commit;
463         if (!empty_commit)
464                 return 0;
465         else
466                 return 1;
467 }
468
469 static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
470 {
471         unsigned char head[20];
472         struct commit *base, *next, *parent;
473         const char *base_label, *next_label;
474         struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
475         char *defmsg = NULL;
476         struct strbuf msgbuf = STRBUF_INIT;
477         int res, unborn = 0;
478
479         if (opts->no_commit) {
480                 /*
481                  * We do not intend to commit immediately.  We just want to
482                  * merge the differences in, so let's compute the tree
483                  * that represents the "current" state for merge-recursive
484                  * to work on.
485                  */
486                 if (write_cache_as_tree(head, 0, NULL))
487                         die (_("Your index file is unmerged."));
488         } else {
489                 unborn = get_sha1("HEAD", head);
490                 if (unborn)
491                         hashcpy(head, EMPTY_TREE_SHA1_BIN);
492                 if (index_differs_from(unborn ? EMPTY_TREE_SHA1_HEX : "HEAD", 0))
493                         return error_dirty_index(opts);
494         }
495         discard_cache();
496
497         if (!commit->parents) {
498                 parent = NULL;
499         }
500         else if (commit->parents->next) {
501                 /* Reverting or cherry-picking a merge commit */
502                 int cnt;
503                 struct commit_list *p;
504
505                 if (!opts->mainline)
506                         return error(_("Commit %s is a merge but no -m option was given."),
507                                 sha1_to_hex(commit->object.sha1));
508
509                 for (cnt = 1, p = commit->parents;
510                      cnt != opts->mainline && p;
511                      cnt++)
512                         p = p->next;
513                 if (cnt != opts->mainline || !p)
514                         return error(_("Commit %s does not have parent %d"),
515                                 sha1_to_hex(commit->object.sha1), opts->mainline);
516                 parent = p->item;
517         } else if (0 < opts->mainline)
518                 return error(_("Mainline was specified but commit %s is not a merge."),
519                         sha1_to_hex(commit->object.sha1));
520         else
521                 parent = commit->parents->item;
522
523         if (opts->allow_ff &&
524             ((parent && !hashcmp(parent->object.sha1, head)) ||
525              (!parent && unborn)))
526              return fast_forward_to(commit->object.sha1, head, unborn);
527
528         if (parent && parse_commit(parent) < 0)
529                 /* TRANSLATORS: The first %s will be "revert" or
530                    "cherry-pick", the second %s a SHA1 */
531                 return error(_("%s: cannot parse parent commit %s"),
532                         action_name(opts), sha1_to_hex(parent->object.sha1));
533
534         if (get_message(commit, &msg) != 0)
535                 return error(_("Cannot get commit message for %s"),
536                         sha1_to_hex(commit->object.sha1));
537
538         /*
539          * "commit" is an existing commit.  We would want to apply
540          * the difference it introduces since its first parent "prev"
541          * on top of the current HEAD if we are cherry-pick.  Or the
542          * reverse of it if we are revert.
543          */
544
545         defmsg = git_pathdup("MERGE_MSG");
546
547         if (opts->action == REPLAY_REVERT) {
548                 base = commit;
549                 base_label = msg.label;
550                 next = parent;
551                 next_label = msg.parent_label;
552                 strbuf_addstr(&msgbuf, "Revert \"");
553                 strbuf_addstr(&msgbuf, msg.subject);
554                 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
555                 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
556
557                 if (commit->parents && commit->parents->next) {
558                         strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
559                         strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
560                 }
561                 strbuf_addstr(&msgbuf, ".\n");
562         } else {
563                 const char *p;
564
565                 base = parent;
566                 base_label = msg.parent_label;
567                 next = commit;
568                 next_label = msg.label;
569
570                 /*
571                  * Append the commit log message to msgbuf; it starts
572                  * after the tree, parent, author, committer
573                  * information followed by "\n\n".
574                  */
575                 p = strstr(msg.message, "\n\n");
576                 if (p) {
577                         p += 2;
578                         strbuf_addstr(&msgbuf, p);
579                 }
580
581                 if (opts->record_origin) {
582                         if (!has_conforming_footer(&msgbuf, NULL, 0))
583                                 strbuf_addch(&msgbuf, '\n');
584                         strbuf_addstr(&msgbuf, cherry_picked_prefix);
585                         strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
586                         strbuf_addstr(&msgbuf, ")\n");
587                 }
588         }
589
590         if (!opts->strategy || !strcmp(opts->strategy, "recursive") || opts->action == REPLAY_REVERT) {
591                 res = do_recursive_merge(base, next, base_label, next_label,
592                                          head, &msgbuf, opts);
593                 write_message(&msgbuf, defmsg);
594         } else {
595                 struct commit_list *common = NULL;
596                 struct commit_list *remotes = NULL;
597
598                 write_message(&msgbuf, defmsg);
599
600                 commit_list_insert(base, &common);
601                 commit_list_insert(next, &remotes);
602                 res = try_merge_command(opts->strategy, opts->xopts_nr, opts->xopts,
603                                         common, sha1_to_hex(head), remotes);
604                 free_commit_list(common);
605                 free_commit_list(remotes);
606         }
607
608         /*
609          * If the merge was clean or if it failed due to conflict, we write
610          * CHERRY_PICK_HEAD for the subsequent invocation of commit to use.
611          * However, if the merge did not even start, then we don't want to
612          * write it at all.
613          */
614         if (opts->action == REPLAY_PICK && !opts->no_commit && (res == 0 || res == 1))
615                 write_cherry_pick_head(commit, "CHERRY_PICK_HEAD");
616         if (opts->action == REPLAY_REVERT && ((opts->no_commit && res == 0) || res == 1))
617                 write_cherry_pick_head(commit, "REVERT_HEAD");
618
619         if (res) {
620                 error(opts->action == REPLAY_REVERT
621                       ? _("could not revert %s... %s")
622                       : _("could not apply %s... %s"),
623                       find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV),
624                       msg.subject);
625                 print_advice(res == 1, opts);
626                 rerere(opts->allow_rerere_auto);
627         } else {
628                 int allow = allow_empty(opts, commit);
629                 if (allow < 0)
630                         return allow;
631                 if (!opts->no_commit)
632                         res = run_git_commit(defmsg, opts, allow);
633         }
634
635         free_message(&msg);
636         free(defmsg);
637
638         return res;
639 }
640
641 static void prepare_revs(struct replay_opts *opts)
642 {
643         /*
644          * picking (but not reverting) ranges (but not individual revisions)
645          * should be done in reverse
646          */
647         if (opts->action == REPLAY_PICK && !opts->revs->no_walk)
648                 opts->revs->reverse ^= 1;
649
650         if (prepare_revision_walk(opts->revs))
651                 die(_("revision walk setup failed"));
652
653         if (!opts->revs->commits)
654                 die(_("empty commit set passed"));
655 }
656
657 static void read_and_refresh_cache(struct replay_opts *opts)
658 {
659         static struct lock_file index_lock;
660         int index_fd = hold_locked_index(&index_lock, 0);
661         if (read_index_preload(&the_index, NULL) < 0)
662                 die(_("git %s: failed to read the index"), action_name(opts));
663         refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
664         if (the_index.cache_changed) {
665                 if (write_index(&the_index, index_fd) ||
666                     commit_locked_index(&index_lock))
667                         die(_("git %s: failed to refresh the index"), action_name(opts));
668         }
669         rollback_lock_file(&index_lock);
670 }
671
672 static int format_todo(struct strbuf *buf, struct commit_list *todo_list,
673                 struct replay_opts *opts)
674 {
675         struct commit_list *cur = NULL;
676         const char *sha1_abbrev = NULL;
677         const char *action_str = opts->action == REPLAY_REVERT ? "revert" : "pick";
678         const char *subject;
679         int subject_len;
680
681         for (cur = todo_list; cur; cur = cur->next) {
682                 sha1_abbrev = find_unique_abbrev(cur->item->object.sha1, DEFAULT_ABBREV);
683                 subject_len = find_commit_subject(cur->item->buffer, &subject);
684                 strbuf_addf(buf, "%s %s %.*s\n", action_str, sha1_abbrev,
685                         subject_len, subject);
686         }
687         return 0;
688 }
689
690 static struct commit *parse_insn_line(char *bol, char *eol, struct replay_opts *opts)
691 {
692         unsigned char commit_sha1[20];
693         enum replay_action action;
694         char *end_of_object_name;
695         int saved, status, padding;
696
697         if (!prefixcmp(bol, "pick")) {
698                 action = REPLAY_PICK;
699                 bol += strlen("pick");
700         } else if (!prefixcmp(bol, "revert")) {
701                 action = REPLAY_REVERT;
702                 bol += strlen("revert");
703         } else
704                 return NULL;
705
706         /* Eat up extra spaces/ tabs before object name */
707         padding = strspn(bol, " \t");
708         if (!padding)
709                 return NULL;
710         bol += padding;
711
712         end_of_object_name = bol + strcspn(bol, " \t\n");
713         saved = *end_of_object_name;
714         *end_of_object_name = '\0';
715         status = get_sha1(bol, commit_sha1);
716         *end_of_object_name = saved;
717
718         /*
719          * Verify that the action matches up with the one in
720          * opts; we don't support arbitrary instructions
721          */
722         if (action != opts->action) {
723                 const char *action_str;
724                 action_str = action == REPLAY_REVERT ? "revert" : "cherry-pick";
725                 error(_("Cannot %s during a %s"), action_str, action_name(opts));
726                 return NULL;
727         }
728
729         if (status < 0)
730                 return NULL;
731
732         return lookup_commit_reference(commit_sha1);
733 }
734
735 static int parse_insn_buffer(char *buf, struct commit_list **todo_list,
736                         struct replay_opts *opts)
737 {
738         struct commit_list **next = todo_list;
739         struct commit *commit;
740         char *p = buf;
741         int i;
742
743         for (i = 1; *p; i++) {
744                 char *eol = strchrnul(p, '\n');
745                 commit = parse_insn_line(p, eol, opts);
746                 if (!commit)
747                         return error(_("Could not parse line %d."), i);
748                 next = commit_list_append(commit, next);
749                 p = *eol ? eol + 1 : eol;
750         }
751         if (!*todo_list)
752                 return error(_("No commits parsed."));
753         return 0;
754 }
755
756 static void read_populate_todo(struct commit_list **todo_list,
757                         struct replay_opts *opts)
758 {
759         const char *todo_file = git_path(SEQ_TODO_FILE);
760         struct strbuf buf = STRBUF_INIT;
761         int fd, res;
762
763         fd = open(todo_file, O_RDONLY);
764         if (fd < 0)
765                 die_errno(_("Could not open %s"), todo_file);
766         if (strbuf_read(&buf, fd, 0) < 0) {
767                 close(fd);
768                 strbuf_release(&buf);
769                 die(_("Could not read %s."), todo_file);
770         }
771         close(fd);
772
773         res = parse_insn_buffer(buf.buf, todo_list, opts);
774         strbuf_release(&buf);
775         if (res)
776                 die(_("Unusable instruction sheet: %s"), todo_file);
777 }
778
779 static int populate_opts_cb(const char *key, const char *value, void *data)
780 {
781         struct replay_opts *opts = data;
782         int error_flag = 1;
783
784         if (!value)
785                 error_flag = 0;
786         else if (!strcmp(key, "options.no-commit"))
787                 opts->no_commit = git_config_bool_or_int(key, value, &error_flag);
788         else if (!strcmp(key, "options.edit"))
789                 opts->edit = git_config_bool_or_int(key, value, &error_flag);
790         else if (!strcmp(key, "options.signoff"))
791                 opts->signoff = git_config_bool_or_int(key, value, &error_flag);
792         else if (!strcmp(key, "options.record-origin"))
793                 opts->record_origin = git_config_bool_or_int(key, value, &error_flag);
794         else if (!strcmp(key, "options.allow-ff"))
795                 opts->allow_ff = git_config_bool_or_int(key, value, &error_flag);
796         else if (!strcmp(key, "options.mainline"))
797                 opts->mainline = git_config_int(key, value);
798         else if (!strcmp(key, "options.strategy"))
799                 git_config_string(&opts->strategy, key, value);
800         else if (!strcmp(key, "options.strategy-option")) {
801                 ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
802                 opts->xopts[opts->xopts_nr++] = xstrdup(value);
803         } else
804                 return error(_("Invalid key: %s"), key);
805
806         if (!error_flag)
807                 return error(_("Invalid value for %s: %s"), key, value);
808
809         return 0;
810 }
811
812 static void read_populate_opts(struct replay_opts **opts_ptr)
813 {
814         const char *opts_file = git_path(SEQ_OPTS_FILE);
815
816         if (!file_exists(opts_file))
817                 return;
818         if (git_config_from_file(populate_opts_cb, opts_file, *opts_ptr) < 0)
819                 die(_("Malformed options sheet: %s"), opts_file);
820 }
821
822 static void walk_revs_populate_todo(struct commit_list **todo_list,
823                                 struct replay_opts *opts)
824 {
825         struct commit *commit;
826         struct commit_list **next;
827
828         prepare_revs(opts);
829
830         next = todo_list;
831         while ((commit = get_revision(opts->revs)))
832                 next = commit_list_append(commit, next);
833 }
834
835 static int create_seq_dir(void)
836 {
837         const char *seq_dir = git_path(SEQ_DIR);
838
839         if (file_exists(seq_dir)) {
840                 error(_("a cherry-pick or revert is already in progress"));
841                 advise(_("try \"git cherry-pick (--continue | --quit | --abort)\""));
842                 return -1;
843         }
844         else if (mkdir(seq_dir, 0777) < 0)
845                 die_errno(_("Could not create sequencer directory %s"), seq_dir);
846         return 0;
847 }
848
849 static void save_head(const char *head)
850 {
851         const char *head_file = git_path(SEQ_HEAD_FILE);
852         static struct lock_file head_lock;
853         struct strbuf buf = STRBUF_INIT;
854         int fd;
855
856         fd = hold_lock_file_for_update(&head_lock, head_file, LOCK_DIE_ON_ERROR);
857         strbuf_addf(&buf, "%s\n", head);
858         if (write_in_full(fd, buf.buf, buf.len) < 0)
859                 die_errno(_("Could not write to %s"), head_file);
860         if (commit_lock_file(&head_lock) < 0)
861                 die(_("Error wrapping up %s."), head_file);
862 }
863
864 static int reset_for_rollback(const unsigned char *sha1)
865 {
866         const char *argv[4];    /* reset --merge <arg> + NULL */
867         argv[0] = "reset";
868         argv[1] = "--merge";
869         argv[2] = sha1_to_hex(sha1);
870         argv[3] = NULL;
871         return run_command_v_opt(argv, RUN_GIT_CMD);
872 }
873
874 static int rollback_single_pick(void)
875 {
876         unsigned char head_sha1[20];
877
878         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
879             !file_exists(git_path("REVERT_HEAD")))
880                 return error(_("no cherry-pick or revert in progress"));
881         if (read_ref_full("HEAD", head_sha1, 0, NULL))
882                 return error(_("cannot resolve HEAD"));
883         if (is_null_sha1(head_sha1))
884                 return error(_("cannot abort from a branch yet to be born"));
885         return reset_for_rollback(head_sha1);
886 }
887
888 static int sequencer_rollback(struct replay_opts *opts)
889 {
890         const char *filename;
891         FILE *f;
892         unsigned char sha1[20];
893         struct strbuf buf = STRBUF_INIT;
894
895         filename = git_path(SEQ_HEAD_FILE);
896         f = fopen(filename, "r");
897         if (!f && errno == ENOENT) {
898                 /*
899                  * There is no multiple-cherry-pick in progress.
900                  * If CHERRY_PICK_HEAD or REVERT_HEAD indicates
901                  * a single-cherry-pick in progress, abort that.
902                  */
903                 return rollback_single_pick();
904         }
905         if (!f)
906                 return error(_("cannot open %s: %s"), filename,
907                                                 strerror(errno));
908         if (strbuf_getline(&buf, f, '\n')) {
909                 error(_("cannot read %s: %s"), filename, ferror(f) ?
910                         strerror(errno) : _("unexpected end of file"));
911                 fclose(f);
912                 goto fail;
913         }
914         fclose(f);
915         if (get_sha1_hex(buf.buf, sha1) || buf.buf[40] != '\0') {
916                 error(_("stored pre-cherry-pick HEAD file '%s' is corrupt"),
917                         filename);
918                 goto fail;
919         }
920         if (reset_for_rollback(sha1))
921                 goto fail;
922         remove_sequencer_state();
923         strbuf_release(&buf);
924         return 0;
925 fail:
926         strbuf_release(&buf);
927         return -1;
928 }
929
930 static void save_todo(struct commit_list *todo_list, struct replay_opts *opts)
931 {
932         const char *todo_file = git_path(SEQ_TODO_FILE);
933         static struct lock_file todo_lock;
934         struct strbuf buf = STRBUF_INIT;
935         int fd;
936
937         fd = hold_lock_file_for_update(&todo_lock, todo_file, LOCK_DIE_ON_ERROR);
938         if (format_todo(&buf, todo_list, opts) < 0)
939                 die(_("Could not format %s."), todo_file);
940         if (write_in_full(fd, buf.buf, buf.len) < 0) {
941                 strbuf_release(&buf);
942                 die_errno(_("Could not write to %s"), todo_file);
943         }
944         if (commit_lock_file(&todo_lock) < 0) {
945                 strbuf_release(&buf);
946                 die(_("Error wrapping up %s."), todo_file);
947         }
948         strbuf_release(&buf);
949 }
950
951 static void save_opts(struct replay_opts *opts)
952 {
953         const char *opts_file = git_path(SEQ_OPTS_FILE);
954
955         if (opts->no_commit)
956                 git_config_set_in_file(opts_file, "options.no-commit", "true");
957         if (opts->edit)
958                 git_config_set_in_file(opts_file, "options.edit", "true");
959         if (opts->signoff)
960                 git_config_set_in_file(opts_file, "options.signoff", "true");
961         if (opts->record_origin)
962                 git_config_set_in_file(opts_file, "options.record-origin", "true");
963         if (opts->allow_ff)
964                 git_config_set_in_file(opts_file, "options.allow-ff", "true");
965         if (opts->mainline) {
966                 struct strbuf buf = STRBUF_INIT;
967                 strbuf_addf(&buf, "%d", opts->mainline);
968                 git_config_set_in_file(opts_file, "options.mainline", buf.buf);
969                 strbuf_release(&buf);
970         }
971         if (opts->strategy)
972                 git_config_set_in_file(opts_file, "options.strategy", opts->strategy);
973         if (opts->xopts) {
974                 int i;
975                 for (i = 0; i < opts->xopts_nr; i++)
976                         git_config_set_multivar_in_file(opts_file,
977                                                         "options.strategy-option",
978                                                         opts->xopts[i], "^$", 0);
979         }
980 }
981
982 static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
983 {
984         struct commit_list *cur;
985         int res;
986
987         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
988         if (opts->allow_ff)
989                 assert(!(opts->signoff || opts->no_commit ||
990                                 opts->record_origin || opts->edit));
991         read_and_refresh_cache(opts);
992
993         for (cur = todo_list; cur; cur = cur->next) {
994                 save_todo(cur, opts);
995                 res = do_pick_commit(cur->item, opts);
996                 if (res)
997                         return res;
998         }
999
1000         /*
1001          * Sequence of picks finished successfully; cleanup by
1002          * removing the .git/sequencer directory
1003          */
1004         remove_sequencer_state();
1005         return 0;
1006 }
1007
1008 static int continue_single_pick(void)
1009 {
1010         const char *argv[] = { "commit", NULL };
1011
1012         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
1013             !file_exists(git_path("REVERT_HEAD")))
1014                 return error(_("no cherry-pick or revert in progress"));
1015         return run_command_v_opt(argv, RUN_GIT_CMD);
1016 }
1017
1018 static int sequencer_continue(struct replay_opts *opts)
1019 {
1020         struct commit_list *todo_list = NULL;
1021
1022         if (!file_exists(git_path(SEQ_TODO_FILE)))
1023                 return continue_single_pick();
1024         read_populate_opts(&opts);
1025         read_populate_todo(&todo_list, opts);
1026
1027         /* Verify that the conflict has been resolved */
1028         if (file_exists(git_path("CHERRY_PICK_HEAD")) ||
1029             file_exists(git_path("REVERT_HEAD"))) {
1030                 int ret = continue_single_pick();
1031                 if (ret)
1032                         return ret;
1033         }
1034         if (index_differs_from("HEAD", 0))
1035                 return error_dirty_index(opts);
1036         todo_list = todo_list->next;
1037         return pick_commits(todo_list, opts);
1038 }
1039
1040 static int single_pick(struct commit *cmit, struct replay_opts *opts)
1041 {
1042         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
1043         return do_pick_commit(cmit, opts);
1044 }
1045
1046 int sequencer_pick_revisions(struct replay_opts *opts)
1047 {
1048         struct commit_list *todo_list = NULL;
1049         unsigned char sha1[20];
1050         int i;
1051
1052         if (opts->subcommand == REPLAY_NONE)
1053                 assert(opts->revs);
1054
1055         read_and_refresh_cache(opts);
1056
1057         /*
1058          * Decide what to do depending on the arguments; a fresh
1059          * cherry-pick should be handled differently from an existing
1060          * one that is being continued
1061          */
1062         if (opts->subcommand == REPLAY_REMOVE_STATE) {
1063                 remove_sequencer_state();
1064                 return 0;
1065         }
1066         if (opts->subcommand == REPLAY_ROLLBACK)
1067                 return sequencer_rollback(opts);
1068         if (opts->subcommand == REPLAY_CONTINUE)
1069                 return sequencer_continue(opts);
1070
1071         for (i = 0; i < opts->revs->pending.nr; i++) {
1072                 unsigned char sha1[20];
1073                 const char *name = opts->revs->pending.objects[i].name;
1074
1075                 /* This happens when using --stdin. */
1076                 if (!strlen(name))
1077                         continue;
1078
1079                 if (!get_sha1(name, sha1)) {
1080                         enum object_type type = sha1_object_info(sha1, NULL);
1081
1082                         if (type > 0 && type != OBJ_COMMIT)
1083                                 die(_("%s: can't cherry-pick a %s"), name, typename(type));
1084                 } else
1085                         die(_("%s: bad revision"), name);
1086         }
1087
1088         /*
1089          * If we were called as "git cherry-pick <commit>", just
1090          * cherry-pick/revert it, set CHERRY_PICK_HEAD /
1091          * REVERT_HEAD, and don't touch the sequencer state.
1092          * This means it is possible to cherry-pick in the middle
1093          * of a cherry-pick sequence.
1094          */
1095         if (opts->revs->cmdline.nr == 1 &&
1096             opts->revs->cmdline.rev->whence == REV_CMD_REV &&
1097             opts->revs->no_walk &&
1098             !opts->revs->cmdline.rev->flags) {
1099                 struct commit *cmit;
1100                 if (prepare_revision_walk(opts->revs))
1101                         die(_("revision walk setup failed"));
1102                 cmit = get_revision(opts->revs);
1103                 if (!cmit || get_revision(opts->revs))
1104                         die("BUG: expected exactly one commit from walk");
1105                 return single_pick(cmit, opts);
1106         }
1107
1108         /*
1109          * Start a new cherry-pick/ revert sequence; but
1110          * first, make sure that an existing one isn't in
1111          * progress
1112          */
1113
1114         walk_revs_populate_todo(&todo_list, opts);
1115         if (create_seq_dir() < 0)
1116                 return -1;
1117         if (get_sha1("HEAD", sha1)) {
1118                 if (opts->action == REPLAY_REVERT)
1119                         return error(_("Can't revert as initial commit"));
1120                 return error(_("Can't cherry-pick into empty head"));
1121         }
1122         save_head(sha1_to_hex(sha1));
1123         save_opts(opts);
1124         return pick_commits(todo_list, opts);
1125 }
1126
1127 void append_signoff(struct strbuf *msgbuf, int ignore_footer, unsigned flag)
1128 {
1129         unsigned no_dup_sob = flag & APPEND_SIGNOFF_DEDUP;
1130         struct strbuf sob = STRBUF_INIT;
1131         int has_footer;
1132
1133         strbuf_addstr(&sob, sign_off_header);
1134         strbuf_addstr(&sob, fmt_name(getenv("GIT_COMMITTER_NAME"),
1135                                 getenv("GIT_COMMITTER_EMAIL")));
1136         strbuf_addch(&sob, '\n');
1137
1138         /*
1139          * If the whole message buffer is equal to the sob, pretend that we
1140          * found a conforming footer with a matching sob
1141          */
1142         if (msgbuf->len - ignore_footer == sob.len &&
1143             !strncmp(msgbuf->buf, sob.buf, sob.len))
1144                 has_footer = 3;
1145         else
1146                 has_footer = has_conforming_footer(msgbuf, &sob, ignore_footer);
1147
1148         if (!has_footer) {
1149                 const char *append_newlines = NULL;
1150                 size_t len = msgbuf->len - ignore_footer;
1151
1152                 if (!len) {
1153                         /*
1154                          * The buffer is completely empty.  Leave foom for
1155                          * the title and body to be filled in by the user.
1156                          */
1157                         append_newlines = "\n\n";
1158                 } else if (msgbuf->buf[len - 1] != '\n') {
1159                         /*
1160                          * Incomplete line.  Complete the line and add a
1161                          * blank one so that there is an empty line between
1162                          * the message body and the sob.
1163                          */
1164                         append_newlines = "\n\n";
1165                 } else if (len == 1) {
1166                         /*
1167                          * Buffer contains a single newline.  Add another
1168                          * so that we leave room for the title and body.
1169                          */
1170                         append_newlines = "\n";
1171                 } else if (msgbuf->buf[len - 2] != '\n') {
1172                         /*
1173                          * Buffer ends with a single newline.  Add another
1174                          * so that there is an empty line between the message
1175                          * body and the sob.
1176                          */
1177                         append_newlines = "\n";
1178                 } /* else, the buffer already ends with two newlines. */
1179
1180                 if (append_newlines)
1181                         strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0,
1182                                 append_newlines, strlen(append_newlines));
1183         }
1184
1185         if (has_footer != 3 && (!no_dup_sob || has_footer != 2))
1186                 strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0,
1187                                 sob.buf, sob.len);
1188
1189         strbuf_release(&sob);
1190 }