Merge branch 'jn/branch-lift-unnecessary-name-length-limit'
[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                 starts_with(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 (starts_with(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, struct replay_opts *opts)
274 {
275         struct ref_lock *ref_lock;
276         struct strbuf sb = STRBUF_INIT;
277         int ret;
278
279         read_cache();
280         if (checkout_fast_forward(from, to, 1))
281                 exit(1); /* the callee should have complained already */
282         ref_lock = lock_any_ref_for_update("HEAD", unborn ? null_sha1 : from,
283                                            0, NULL);
284         strbuf_addf(&sb, "%s: fast-forward", action_name(opts));
285         ret = write_ref_sha1(ref_lock, to, sb.buf);
286         strbuf_release(&sb);
287         return ret;
288 }
289
290 static int do_recursive_merge(struct commit *base, struct commit *next,
291                               const char *base_label, const char *next_label,
292                               unsigned char *head, struct strbuf *msgbuf,
293                               struct replay_opts *opts)
294 {
295         struct merge_options o;
296         struct tree *result, *next_tree, *base_tree, *head_tree;
297         int clean, index_fd;
298         const char **xopt;
299         static struct lock_file index_lock;
300
301         index_fd = hold_locked_index(&index_lock, 1);
302
303         read_cache();
304
305         init_merge_options(&o);
306         o.ancestor = base ? base_label : "(empty tree)";
307         o.branch1 = "HEAD";
308         o.branch2 = next ? next_label : "(empty tree)";
309
310         head_tree = parse_tree_indirect(head);
311         next_tree = next ? next->tree : empty_tree();
312         base_tree = base ? base->tree : empty_tree();
313
314         for (xopt = opts->xopts; xopt != opts->xopts + opts->xopts_nr; xopt++)
315                 parse_merge_opt(&o, *xopt);
316
317         clean = merge_trees(&o,
318                             head_tree,
319                             next_tree, base_tree, &result);
320
321         if (active_cache_changed &&
322             (write_cache(index_fd, active_cache, active_nr) ||
323              commit_locked_index(&index_lock)))
324                 /* TRANSLATORS: %s will be "revert" or "cherry-pick" */
325                 die(_("%s: Unable to write new index file"), action_name(opts));
326         rollback_lock_file(&index_lock);
327
328         if (opts->signoff)
329                 append_signoff(msgbuf, 0, 0);
330
331         if (!clean) {
332                 int i;
333                 strbuf_addstr(msgbuf, "\nConflicts:\n");
334                 for (i = 0; i < active_nr;) {
335                         const struct cache_entry *ce = active_cache[i++];
336                         if (ce_stage(ce)) {
337                                 strbuf_addch(msgbuf, '\t');
338                                 strbuf_addstr(msgbuf, ce->name);
339                                 strbuf_addch(msgbuf, '\n');
340                                 while (i < active_nr && !strcmp(ce->name,
341                                                 active_cache[i]->name))
342                                         i++;
343                         }
344                 }
345         }
346
347         return !clean;
348 }
349
350 static int is_index_unchanged(void)
351 {
352         unsigned char head_sha1[20];
353         struct commit *head_commit;
354
355         if (!resolve_ref_unsafe("HEAD", head_sha1, 1, NULL))
356                 return error(_("Could not resolve HEAD commit\n"));
357
358         head_commit = lookup_commit(head_sha1);
359
360         /*
361          * If head_commit is NULL, check_commit, called from
362          * lookup_commit, would have indicated that head_commit is not
363          * a commit object already.  parse_commit() will return failure
364          * without further complaints in such a case.  Otherwise, if
365          * the commit is invalid, parse_commit() will complain.  So
366          * there is nothing for us to say here.  Just return failure.
367          */
368         if (parse_commit(head_commit))
369                 return -1;
370
371         if (!active_cache_tree)
372                 active_cache_tree = cache_tree();
373
374         if (!cache_tree_fully_valid(active_cache_tree))
375                 if (cache_tree_update(active_cache_tree,
376                                       (const struct cache_entry * const *)active_cache,
377                                       active_nr, 0))
378                         return error(_("Unable to update cache tree\n"));
379
380         return !hashcmp(active_cache_tree->sha1, head_commit->tree->object.sha1);
381 }
382
383 /*
384  * If we are cherry-pick, and if the merge did not result in
385  * hand-editing, we will hit this commit and inherit the original
386  * author date and name.
387  * If we are revert, or if our cherry-pick results in a hand merge,
388  * we had better say that the current user is responsible for that.
389  */
390 static int run_git_commit(const char *defmsg, struct replay_opts *opts,
391                           int allow_empty)
392 {
393         struct argv_array array;
394         int rc;
395         char *gpg_sign;
396
397         argv_array_init(&array);
398         argv_array_push(&array, "commit");
399         argv_array_push(&array, "-n");
400
401         if (opts->gpg_sign) {
402                 gpg_sign = xmalloc(3 + strlen(opts->gpg_sign));
403                 sprintf(gpg_sign, "-S%s", opts->gpg_sign);
404                 argv_array_push(&array, gpg_sign);
405                 free(gpg_sign);
406         }
407         if (opts->signoff)
408                 argv_array_push(&array, "-s");
409         if (!opts->edit) {
410                 argv_array_push(&array, "-F");
411                 argv_array_push(&array, defmsg);
412         }
413
414         if (allow_empty)
415                 argv_array_push(&array, "--allow-empty");
416
417         if (opts->allow_empty_message)
418                 argv_array_push(&array, "--allow-empty-message");
419
420         rc = run_command_v_opt(array.argv, RUN_GIT_CMD);
421         argv_array_clear(&array);
422         return rc;
423 }
424
425 static int is_original_commit_empty(struct commit *commit)
426 {
427         const unsigned char *ptree_sha1;
428
429         if (parse_commit(commit))
430                 return error(_("Could not parse commit %s\n"),
431                              sha1_to_hex(commit->object.sha1));
432         if (commit->parents) {
433                 struct commit *parent = commit->parents->item;
434                 if (parse_commit(parent))
435                         return error(_("Could not parse parent commit %s\n"),
436                                 sha1_to_hex(parent->object.sha1));
437                 ptree_sha1 = parent->tree->object.sha1;
438         } else {
439                 ptree_sha1 = EMPTY_TREE_SHA1_BIN; /* commit is root */
440         }
441
442         return !hashcmp(ptree_sha1, commit->tree->object.sha1);
443 }
444
445 /*
446  * Do we run "git commit" with "--allow-empty"?
447  */
448 static int allow_empty(struct replay_opts *opts, struct commit *commit)
449 {
450         int index_unchanged, empty_commit;
451
452         /*
453          * Three cases:
454          *
455          * (1) we do not allow empty at all and error out.
456          *
457          * (2) we allow ones that were initially empty, but
458          * forbid the ones that become empty;
459          *
460          * (3) we allow both.
461          */
462         if (!opts->allow_empty)
463                 return 0; /* let "git commit" barf as necessary */
464
465         index_unchanged = is_index_unchanged();
466         if (index_unchanged < 0)
467                 return index_unchanged;
468         if (!index_unchanged)
469                 return 0; /* we do not have to say --allow-empty */
470
471         if (opts->keep_redundant_commits)
472                 return 1;
473
474         empty_commit = is_original_commit_empty(commit);
475         if (empty_commit < 0)
476                 return empty_commit;
477         if (!empty_commit)
478                 return 0;
479         else
480                 return 1;
481 }
482
483 static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
484 {
485         unsigned char head[20];
486         struct commit *base, *next, *parent;
487         const char *base_label, *next_label;
488         struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
489         char *defmsg = NULL;
490         struct strbuf msgbuf = STRBUF_INIT;
491         int res, unborn = 0, allow;
492
493         if (opts->no_commit) {
494                 /*
495                  * We do not intend to commit immediately.  We just want to
496                  * merge the differences in, so let's compute the tree
497                  * that represents the "current" state for merge-recursive
498                  * to work on.
499                  */
500                 if (write_cache_as_tree(head, 0, NULL))
501                         die (_("Your index file is unmerged."));
502         } else {
503                 unborn = get_sha1("HEAD", head);
504                 if (unborn)
505                         hashcpy(head, EMPTY_TREE_SHA1_BIN);
506                 if (index_differs_from(unborn ? EMPTY_TREE_SHA1_HEX : "HEAD", 0))
507                         return error_dirty_index(opts);
508         }
509         discard_cache();
510
511         if (!commit->parents) {
512                 parent = NULL;
513         }
514         else if (commit->parents->next) {
515                 /* Reverting or cherry-picking a merge commit */
516                 int cnt;
517                 struct commit_list *p;
518
519                 if (!opts->mainline)
520                         return error(_("Commit %s is a merge but no -m option was given."),
521                                 sha1_to_hex(commit->object.sha1));
522
523                 for (cnt = 1, p = commit->parents;
524                      cnt != opts->mainline && p;
525                      cnt++)
526                         p = p->next;
527                 if (cnt != opts->mainline || !p)
528                         return error(_("Commit %s does not have parent %d"),
529                                 sha1_to_hex(commit->object.sha1), opts->mainline);
530                 parent = p->item;
531         } else if (0 < opts->mainline)
532                 return error(_("Mainline was specified but commit %s is not a merge."),
533                         sha1_to_hex(commit->object.sha1));
534         else
535                 parent = commit->parents->item;
536
537         if (opts->allow_ff &&
538             ((parent && !hashcmp(parent->object.sha1, head)) ||
539              (!parent && unborn)))
540                 return fast_forward_to(commit->object.sha1, head, unborn, opts);
541
542         if (parent && parse_commit(parent) < 0)
543                 /* TRANSLATORS: The first %s will be "revert" or
544                    "cherry-pick", the second %s a SHA1 */
545                 return error(_("%s: cannot parse parent commit %s"),
546                         action_name(opts), sha1_to_hex(parent->object.sha1));
547
548         if (get_message(commit, &msg) != 0)
549                 return error(_("Cannot get commit message for %s"),
550                         sha1_to_hex(commit->object.sha1));
551
552         /*
553          * "commit" is an existing commit.  We would want to apply
554          * the difference it introduces since its first parent "prev"
555          * on top of the current HEAD if we are cherry-pick.  Or the
556          * reverse of it if we are revert.
557          */
558
559         defmsg = git_pathdup("MERGE_MSG");
560
561         if (opts->action == REPLAY_REVERT) {
562                 base = commit;
563                 base_label = msg.label;
564                 next = parent;
565                 next_label = msg.parent_label;
566                 strbuf_addstr(&msgbuf, "Revert \"");
567                 strbuf_addstr(&msgbuf, msg.subject);
568                 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
569                 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
570
571                 if (commit->parents && commit->parents->next) {
572                         strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
573                         strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
574                 }
575                 strbuf_addstr(&msgbuf, ".\n");
576         } else {
577                 const char *p;
578
579                 base = parent;
580                 base_label = msg.parent_label;
581                 next = commit;
582                 next_label = msg.label;
583
584                 /*
585                  * Append the commit log message to msgbuf; it starts
586                  * after the tree, parent, author, committer
587                  * information followed by "\n\n".
588                  */
589                 p = strstr(msg.message, "\n\n");
590                 if (p) {
591                         p += 2;
592                         strbuf_addstr(&msgbuf, p);
593                 }
594
595                 if (opts->record_origin) {
596                         if (!has_conforming_footer(&msgbuf, NULL, 0))
597                                 strbuf_addch(&msgbuf, '\n');
598                         strbuf_addstr(&msgbuf, cherry_picked_prefix);
599                         strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
600                         strbuf_addstr(&msgbuf, ")\n");
601                 }
602         }
603
604         if (!opts->strategy || !strcmp(opts->strategy, "recursive") || opts->action == REPLAY_REVERT) {
605                 res = do_recursive_merge(base, next, base_label, next_label,
606                                          head, &msgbuf, opts);
607                 write_message(&msgbuf, defmsg);
608         } else {
609                 struct commit_list *common = NULL;
610                 struct commit_list *remotes = NULL;
611
612                 write_message(&msgbuf, defmsg);
613
614                 commit_list_insert(base, &common);
615                 commit_list_insert(next, &remotes);
616                 res = try_merge_command(opts->strategy, opts->xopts_nr, opts->xopts,
617                                         common, sha1_to_hex(head), remotes);
618                 free_commit_list(common);
619                 free_commit_list(remotes);
620         }
621
622         /*
623          * If the merge was clean or if it failed due to conflict, we write
624          * CHERRY_PICK_HEAD for the subsequent invocation of commit to use.
625          * However, if the merge did not even start, then we don't want to
626          * write it at all.
627          */
628         if (opts->action == REPLAY_PICK && !opts->no_commit && (res == 0 || res == 1))
629                 write_cherry_pick_head(commit, "CHERRY_PICK_HEAD");
630         if (opts->action == REPLAY_REVERT && ((opts->no_commit && res == 0) || res == 1))
631                 write_cherry_pick_head(commit, "REVERT_HEAD");
632
633         if (res) {
634                 error(opts->action == REPLAY_REVERT
635                       ? _("could not revert %s... %s")
636                       : _("could not apply %s... %s"),
637                       find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV),
638                       msg.subject);
639                 print_advice(res == 1, opts);
640                 rerere(opts->allow_rerere_auto);
641                 goto leave;
642         }
643
644         allow = allow_empty(opts, commit);
645         if (allow < 0) {
646                 res = allow;
647                 goto leave;
648         }
649         if (!opts->no_commit)
650                 res = run_git_commit(defmsg, opts, allow);
651
652 leave:
653         free_message(&msg);
654         free(defmsg);
655
656         return res;
657 }
658
659 static void prepare_revs(struct replay_opts *opts)
660 {
661         /*
662          * picking (but not reverting) ranges (but not individual revisions)
663          * should be done in reverse
664          */
665         if (opts->action == REPLAY_PICK && !opts->revs->no_walk)
666                 opts->revs->reverse ^= 1;
667
668         if (prepare_revision_walk(opts->revs))
669                 die(_("revision walk setup failed"));
670
671         if (!opts->revs->commits)
672                 die(_("empty commit set passed"));
673 }
674
675 static void read_and_refresh_cache(struct replay_opts *opts)
676 {
677         static struct lock_file index_lock;
678         int index_fd = hold_locked_index(&index_lock, 0);
679         if (read_index_preload(&the_index, NULL) < 0)
680                 die(_("git %s: failed to read the index"), action_name(opts));
681         refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
682         if (the_index.cache_changed) {
683                 if (write_index(&the_index, index_fd) ||
684                     commit_locked_index(&index_lock))
685                         die(_("git %s: failed to refresh the index"), action_name(opts));
686         }
687         rollback_lock_file(&index_lock);
688 }
689
690 static int format_todo(struct strbuf *buf, struct commit_list *todo_list,
691                 struct replay_opts *opts)
692 {
693         struct commit_list *cur = NULL;
694         const char *sha1_abbrev = NULL;
695         const char *action_str = opts->action == REPLAY_REVERT ? "revert" : "pick";
696         const char *subject;
697         int subject_len;
698
699         for (cur = todo_list; cur; cur = cur->next) {
700                 sha1_abbrev = find_unique_abbrev(cur->item->object.sha1, DEFAULT_ABBREV);
701                 subject_len = find_commit_subject(cur->item->buffer, &subject);
702                 strbuf_addf(buf, "%s %s %.*s\n", action_str, sha1_abbrev,
703                         subject_len, subject);
704         }
705         return 0;
706 }
707
708 static struct commit *parse_insn_line(char *bol, char *eol, struct replay_opts *opts)
709 {
710         unsigned char commit_sha1[20];
711         enum replay_action action;
712         char *end_of_object_name;
713         int saved, status, padding;
714
715         if (starts_with(bol, "pick")) {
716                 action = REPLAY_PICK;
717                 bol += strlen("pick");
718         } else if (starts_with(bol, "revert")) {
719                 action = REPLAY_REVERT;
720                 bol += strlen("revert");
721         } else
722                 return NULL;
723
724         /* Eat up extra spaces/ tabs before object name */
725         padding = strspn(bol, " \t");
726         if (!padding)
727                 return NULL;
728         bol += padding;
729
730         end_of_object_name = bol + strcspn(bol, " \t\n");
731         saved = *end_of_object_name;
732         *end_of_object_name = '\0';
733         status = get_sha1(bol, commit_sha1);
734         *end_of_object_name = saved;
735
736         /*
737          * Verify that the action matches up with the one in
738          * opts; we don't support arbitrary instructions
739          */
740         if (action != opts->action) {
741                 const char *action_str;
742                 action_str = action == REPLAY_REVERT ? "revert" : "cherry-pick";
743                 error(_("Cannot %s during a %s"), action_str, action_name(opts));
744                 return NULL;
745         }
746
747         if (status < 0)
748                 return NULL;
749
750         return lookup_commit_reference(commit_sha1);
751 }
752
753 static int parse_insn_buffer(char *buf, struct commit_list **todo_list,
754                         struct replay_opts *opts)
755 {
756         struct commit_list **next = todo_list;
757         struct commit *commit;
758         char *p = buf;
759         int i;
760
761         for (i = 1; *p; i++) {
762                 char *eol = strchrnul(p, '\n');
763                 commit = parse_insn_line(p, eol, opts);
764                 if (!commit)
765                         return error(_("Could not parse line %d."), i);
766                 next = commit_list_append(commit, next);
767                 p = *eol ? eol + 1 : eol;
768         }
769         if (!*todo_list)
770                 return error(_("No commits parsed."));
771         return 0;
772 }
773
774 static void read_populate_todo(struct commit_list **todo_list,
775                         struct replay_opts *opts)
776 {
777         const char *todo_file = git_path(SEQ_TODO_FILE);
778         struct strbuf buf = STRBUF_INIT;
779         int fd, res;
780
781         fd = open(todo_file, O_RDONLY);
782         if (fd < 0)
783                 die_errno(_("Could not open %s"), todo_file);
784         if (strbuf_read(&buf, fd, 0) < 0) {
785                 close(fd);
786                 strbuf_release(&buf);
787                 die(_("Could not read %s."), todo_file);
788         }
789         close(fd);
790
791         res = parse_insn_buffer(buf.buf, todo_list, opts);
792         strbuf_release(&buf);
793         if (res)
794                 die(_("Unusable instruction sheet: %s"), todo_file);
795 }
796
797 static int populate_opts_cb(const char *key, const char *value, void *data)
798 {
799         struct replay_opts *opts = data;
800         int error_flag = 1;
801
802         if (!value)
803                 error_flag = 0;
804         else if (!strcmp(key, "options.no-commit"))
805                 opts->no_commit = git_config_bool_or_int(key, value, &error_flag);
806         else if (!strcmp(key, "options.edit"))
807                 opts->edit = git_config_bool_or_int(key, value, &error_flag);
808         else if (!strcmp(key, "options.signoff"))
809                 opts->signoff = git_config_bool_or_int(key, value, &error_flag);
810         else if (!strcmp(key, "options.record-origin"))
811                 opts->record_origin = git_config_bool_or_int(key, value, &error_flag);
812         else if (!strcmp(key, "options.allow-ff"))
813                 opts->allow_ff = git_config_bool_or_int(key, value, &error_flag);
814         else if (!strcmp(key, "options.mainline"))
815                 opts->mainline = git_config_int(key, value);
816         else if (!strcmp(key, "options.strategy"))
817                 git_config_string(&opts->strategy, key, value);
818         else if (!strcmp(key, "options.gpg-sign"))
819                 git_config_string(&opts->gpg_sign, key, value);
820         else if (!strcmp(key, "options.strategy-option")) {
821                 ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
822                 opts->xopts[opts->xopts_nr++] = xstrdup(value);
823         } else
824                 return error(_("Invalid key: %s"), key);
825
826         if (!error_flag)
827                 return error(_("Invalid value for %s: %s"), key, value);
828
829         return 0;
830 }
831
832 static void read_populate_opts(struct replay_opts **opts_ptr)
833 {
834         const char *opts_file = git_path(SEQ_OPTS_FILE);
835
836         if (!file_exists(opts_file))
837                 return;
838         if (git_config_from_file(populate_opts_cb, opts_file, *opts_ptr) < 0)
839                 die(_("Malformed options sheet: %s"), opts_file);
840 }
841
842 static void walk_revs_populate_todo(struct commit_list **todo_list,
843                                 struct replay_opts *opts)
844 {
845         struct commit *commit;
846         struct commit_list **next;
847
848         prepare_revs(opts);
849
850         next = todo_list;
851         while ((commit = get_revision(opts->revs)))
852                 next = commit_list_append(commit, next);
853 }
854
855 static int create_seq_dir(void)
856 {
857         const char *seq_dir = git_path(SEQ_DIR);
858
859         if (file_exists(seq_dir)) {
860                 error(_("a cherry-pick or revert is already in progress"));
861                 advise(_("try \"git cherry-pick (--continue | --quit | --abort)\""));
862                 return -1;
863         }
864         else if (mkdir(seq_dir, 0777) < 0)
865                 die_errno(_("Could not create sequencer directory %s"), seq_dir);
866         return 0;
867 }
868
869 static void save_head(const char *head)
870 {
871         const char *head_file = git_path(SEQ_HEAD_FILE);
872         static struct lock_file head_lock;
873         struct strbuf buf = STRBUF_INIT;
874         int fd;
875
876         fd = hold_lock_file_for_update(&head_lock, head_file, LOCK_DIE_ON_ERROR);
877         strbuf_addf(&buf, "%s\n", head);
878         if (write_in_full(fd, buf.buf, buf.len) < 0)
879                 die_errno(_("Could not write to %s"), head_file);
880         if (commit_lock_file(&head_lock) < 0)
881                 die(_("Error wrapping up %s."), head_file);
882 }
883
884 static int reset_for_rollback(const unsigned char *sha1)
885 {
886         const char *argv[4];    /* reset --merge <arg> + NULL */
887         argv[0] = "reset";
888         argv[1] = "--merge";
889         argv[2] = sha1_to_hex(sha1);
890         argv[3] = NULL;
891         return run_command_v_opt(argv, RUN_GIT_CMD);
892 }
893
894 static int rollback_single_pick(void)
895 {
896         unsigned char head_sha1[20];
897
898         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
899             !file_exists(git_path("REVERT_HEAD")))
900                 return error(_("no cherry-pick or revert in progress"));
901         if (read_ref_full("HEAD", head_sha1, 0, NULL))
902                 return error(_("cannot resolve HEAD"));
903         if (is_null_sha1(head_sha1))
904                 return error(_("cannot abort from a branch yet to be born"));
905         return reset_for_rollback(head_sha1);
906 }
907
908 static int sequencer_rollback(struct replay_opts *opts)
909 {
910         const char *filename;
911         FILE *f;
912         unsigned char sha1[20];
913         struct strbuf buf = STRBUF_INIT;
914
915         filename = git_path(SEQ_HEAD_FILE);
916         f = fopen(filename, "r");
917         if (!f && errno == ENOENT) {
918                 /*
919                  * There is no multiple-cherry-pick in progress.
920                  * If CHERRY_PICK_HEAD or REVERT_HEAD indicates
921                  * a single-cherry-pick in progress, abort that.
922                  */
923                 return rollback_single_pick();
924         }
925         if (!f)
926                 return error(_("cannot open %s: %s"), filename,
927                                                 strerror(errno));
928         if (strbuf_getline(&buf, f, '\n')) {
929                 error(_("cannot read %s: %s"), filename, ferror(f) ?
930                         strerror(errno) : _("unexpected end of file"));
931                 fclose(f);
932                 goto fail;
933         }
934         fclose(f);
935         if (get_sha1_hex(buf.buf, sha1) || buf.buf[40] != '\0') {
936                 error(_("stored pre-cherry-pick HEAD file '%s' is corrupt"),
937                         filename);
938                 goto fail;
939         }
940         if (reset_for_rollback(sha1))
941                 goto fail;
942         remove_sequencer_state();
943         strbuf_release(&buf);
944         return 0;
945 fail:
946         strbuf_release(&buf);
947         return -1;
948 }
949
950 static void save_todo(struct commit_list *todo_list, struct replay_opts *opts)
951 {
952         const char *todo_file = git_path(SEQ_TODO_FILE);
953         static struct lock_file todo_lock;
954         struct strbuf buf = STRBUF_INIT;
955         int fd;
956
957         fd = hold_lock_file_for_update(&todo_lock, todo_file, LOCK_DIE_ON_ERROR);
958         if (format_todo(&buf, todo_list, opts) < 0)
959                 die(_("Could not format %s."), todo_file);
960         if (write_in_full(fd, buf.buf, buf.len) < 0) {
961                 strbuf_release(&buf);
962                 die_errno(_("Could not write to %s"), todo_file);
963         }
964         if (commit_lock_file(&todo_lock) < 0) {
965                 strbuf_release(&buf);
966                 die(_("Error wrapping up %s."), todo_file);
967         }
968         strbuf_release(&buf);
969 }
970
971 static void save_opts(struct replay_opts *opts)
972 {
973         const char *opts_file = git_path(SEQ_OPTS_FILE);
974
975         if (opts->no_commit)
976                 git_config_set_in_file(opts_file, "options.no-commit", "true");
977         if (opts->edit)
978                 git_config_set_in_file(opts_file, "options.edit", "true");
979         if (opts->signoff)
980                 git_config_set_in_file(opts_file, "options.signoff", "true");
981         if (opts->record_origin)
982                 git_config_set_in_file(opts_file, "options.record-origin", "true");
983         if (opts->allow_ff)
984                 git_config_set_in_file(opts_file, "options.allow-ff", "true");
985         if (opts->mainline) {
986                 struct strbuf buf = STRBUF_INIT;
987                 strbuf_addf(&buf, "%d", opts->mainline);
988                 git_config_set_in_file(opts_file, "options.mainline", buf.buf);
989                 strbuf_release(&buf);
990         }
991         if (opts->strategy)
992                 git_config_set_in_file(opts_file, "options.strategy", opts->strategy);
993         if (opts->gpg_sign)
994                 git_config_set_in_file(opts_file, "options.gpg-sign", opts->gpg_sign);
995         if (opts->xopts) {
996                 int i;
997                 for (i = 0; i < opts->xopts_nr; i++)
998                         git_config_set_multivar_in_file(opts_file,
999                                                         "options.strategy-option",
1000                                                         opts->xopts[i], "^$", 0);
1001         }
1002 }
1003
1004 static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
1005 {
1006         struct commit_list *cur;
1007         int res;
1008
1009         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
1010         if (opts->allow_ff)
1011                 assert(!(opts->signoff || opts->no_commit ||
1012                                 opts->record_origin || opts->edit));
1013         read_and_refresh_cache(opts);
1014
1015         for (cur = todo_list; cur; cur = cur->next) {
1016                 save_todo(cur, opts);
1017                 res = do_pick_commit(cur->item, opts);
1018                 if (res)
1019                         return res;
1020         }
1021
1022         /*
1023          * Sequence of picks finished successfully; cleanup by
1024          * removing the .git/sequencer directory
1025          */
1026         remove_sequencer_state();
1027         return 0;
1028 }
1029
1030 static int continue_single_pick(void)
1031 {
1032         const char *argv[] = { "commit", NULL };
1033
1034         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
1035             !file_exists(git_path("REVERT_HEAD")))
1036                 return error(_("no cherry-pick or revert in progress"));
1037         return run_command_v_opt(argv, RUN_GIT_CMD);
1038 }
1039
1040 static int sequencer_continue(struct replay_opts *opts)
1041 {
1042         struct commit_list *todo_list = NULL;
1043
1044         if (!file_exists(git_path(SEQ_TODO_FILE)))
1045                 return continue_single_pick();
1046         read_populate_opts(&opts);
1047         read_populate_todo(&todo_list, opts);
1048
1049         /* Verify that the conflict has been resolved */
1050         if (file_exists(git_path("CHERRY_PICK_HEAD")) ||
1051             file_exists(git_path("REVERT_HEAD"))) {
1052                 int ret = continue_single_pick();
1053                 if (ret)
1054                         return ret;
1055         }
1056         if (index_differs_from("HEAD", 0))
1057                 return error_dirty_index(opts);
1058         todo_list = todo_list->next;
1059         return pick_commits(todo_list, opts);
1060 }
1061
1062 static int single_pick(struct commit *cmit, struct replay_opts *opts)
1063 {
1064         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
1065         return do_pick_commit(cmit, opts);
1066 }
1067
1068 int sequencer_pick_revisions(struct replay_opts *opts)
1069 {
1070         struct commit_list *todo_list = NULL;
1071         unsigned char sha1[20];
1072         int i;
1073
1074         if (opts->subcommand == REPLAY_NONE)
1075                 assert(opts->revs);
1076
1077         read_and_refresh_cache(opts);
1078
1079         /*
1080          * Decide what to do depending on the arguments; a fresh
1081          * cherry-pick should be handled differently from an existing
1082          * one that is being continued
1083          */
1084         if (opts->subcommand == REPLAY_REMOVE_STATE) {
1085                 remove_sequencer_state();
1086                 return 0;
1087         }
1088         if (opts->subcommand == REPLAY_ROLLBACK)
1089                 return sequencer_rollback(opts);
1090         if (opts->subcommand == REPLAY_CONTINUE)
1091                 return sequencer_continue(opts);
1092
1093         for (i = 0; i < opts->revs->pending.nr; i++) {
1094                 unsigned char sha1[20];
1095                 const char *name = opts->revs->pending.objects[i].name;
1096
1097                 /* This happens when using --stdin. */
1098                 if (!strlen(name))
1099                         continue;
1100
1101                 if (!get_sha1(name, sha1)) {
1102                         if (!lookup_commit_reference_gently(sha1, 1)) {
1103                                 enum object_type type = sha1_object_info(sha1, NULL);
1104                                 die(_("%s: can't cherry-pick a %s"), name, typename(type));
1105                         }
1106                 } else
1107                         die(_("%s: bad revision"), name);
1108         }
1109
1110         /*
1111          * If we were called as "git cherry-pick <commit>", just
1112          * cherry-pick/revert it, set CHERRY_PICK_HEAD /
1113          * REVERT_HEAD, and don't touch the sequencer state.
1114          * This means it is possible to cherry-pick in the middle
1115          * of a cherry-pick sequence.
1116          */
1117         if (opts->revs->cmdline.nr == 1 &&
1118             opts->revs->cmdline.rev->whence == REV_CMD_REV &&
1119             opts->revs->no_walk &&
1120             !opts->revs->cmdline.rev->flags) {
1121                 struct commit *cmit;
1122                 if (prepare_revision_walk(opts->revs))
1123                         die(_("revision walk setup failed"));
1124                 cmit = get_revision(opts->revs);
1125                 if (!cmit || get_revision(opts->revs))
1126                         die("BUG: expected exactly one commit from walk");
1127                 return single_pick(cmit, opts);
1128         }
1129
1130         /*
1131          * Start a new cherry-pick/ revert sequence; but
1132          * first, make sure that an existing one isn't in
1133          * progress
1134          */
1135
1136         walk_revs_populate_todo(&todo_list, opts);
1137         if (create_seq_dir() < 0)
1138                 return -1;
1139         if (get_sha1("HEAD", sha1)) {
1140                 if (opts->action == REPLAY_REVERT)
1141                         return error(_("Can't revert as initial commit"));
1142                 return error(_("Can't cherry-pick into empty head"));
1143         }
1144         save_head(sha1_to_hex(sha1));
1145         save_opts(opts);
1146         return pick_commits(todo_list, opts);
1147 }
1148
1149 void append_signoff(struct strbuf *msgbuf, int ignore_footer, unsigned flag)
1150 {
1151         unsigned no_dup_sob = flag & APPEND_SIGNOFF_DEDUP;
1152         struct strbuf sob = STRBUF_INIT;
1153         int has_footer;
1154
1155         strbuf_addstr(&sob, sign_off_header);
1156         strbuf_addstr(&sob, fmt_name(getenv("GIT_COMMITTER_NAME"),
1157                                 getenv("GIT_COMMITTER_EMAIL")));
1158         strbuf_addch(&sob, '\n');
1159
1160         /*
1161          * If the whole message buffer is equal to the sob, pretend that we
1162          * found a conforming footer with a matching sob
1163          */
1164         if (msgbuf->len - ignore_footer == sob.len &&
1165             !strncmp(msgbuf->buf, sob.buf, sob.len))
1166                 has_footer = 3;
1167         else
1168                 has_footer = has_conforming_footer(msgbuf, &sob, ignore_footer);
1169
1170         if (!has_footer) {
1171                 const char *append_newlines = NULL;
1172                 size_t len = msgbuf->len - ignore_footer;
1173
1174                 if (!len) {
1175                         /*
1176                          * The buffer is completely empty.  Leave foom for
1177                          * the title and body to be filled in by the user.
1178                          */
1179                         append_newlines = "\n\n";
1180                 } else if (msgbuf->buf[len - 1] != '\n') {
1181                         /*
1182                          * Incomplete line.  Complete the line and add a
1183                          * blank one so that there is an empty line between
1184                          * the message body and the sob.
1185                          */
1186                         append_newlines = "\n\n";
1187                 } else if (len == 1) {
1188                         /*
1189                          * Buffer contains a single newline.  Add another
1190                          * so that we leave room for the title and body.
1191                          */
1192                         append_newlines = "\n";
1193                 } else if (msgbuf->buf[len - 2] != '\n') {
1194                         /*
1195                          * Buffer ends with a single newline.  Add another
1196                          * so that there is an empty line between the message
1197                          * body and the sob.
1198                          */
1199                         append_newlines = "\n";
1200                 } /* else, the buffer already ends with two newlines. */
1201
1202                 if (append_newlines)
1203                         strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0,
1204                                 append_newlines, strlen(append_newlines));
1205         }
1206
1207         if (has_footer != 3 && (!no_dup_sob || has_footer != 2))
1208                 strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0,
1209                                 sob.buf, sob.len);
1210
1211         strbuf_release(&sob);
1212 }