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