Merge branches zj/decimal-width, zj/term-columns and jc/diff-stat-scaler
[git] / builtin / revert.c
1 #include "cache.h"
2 #include "builtin.h"
3 #include "object.h"
4 #include "commit.h"
5 #include "tag.h"
6 #include "run-command.h"
7 #include "exec_cmd.h"
8 #include "utf8.h"
9 #include "parse-options.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 "dir.h"
17 #include "sequencer.h"
18
19 /*
20  * This implements the builtins revert and cherry-pick.
21  *
22  * Copyright (c) 2007 Johannes E. Schindelin
23  *
24  * Based on git-revert.sh, which is
25  *
26  * Copyright (c) 2005 Linus Torvalds
27  * Copyright (c) 2005 Junio C Hamano
28  */
29
30 static const char * const revert_usage[] = {
31         "git revert [options] <commit-ish>",
32         "git revert <subcommand>",
33         NULL
34 };
35
36 static const char * const cherry_pick_usage[] = {
37         "git cherry-pick [options] <commit-ish>",
38         "git cherry-pick <subcommand>",
39         NULL
40 };
41
42 enum replay_action { REVERT, CHERRY_PICK };
43 enum replay_subcommand {
44         REPLAY_NONE,
45         REPLAY_REMOVE_STATE,
46         REPLAY_CONTINUE,
47         REPLAY_ROLLBACK
48 };
49
50 struct replay_opts {
51         enum replay_action action;
52         enum replay_subcommand subcommand;
53
54         /* Boolean options */
55         int edit;
56         int record_origin;
57         int no_commit;
58         int signoff;
59         int allow_ff;
60         int allow_rerere_auto;
61
62         int mainline;
63
64         /* Merge strategy */
65         const char *strategy;
66         const char **xopts;
67         size_t xopts_nr, xopts_alloc;
68
69         /* Only used by REPLAY_NONE */
70         struct rev_info *revs;
71 };
72
73 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
74
75 static const char *action_name(const struct replay_opts *opts)
76 {
77         return opts->action == REVERT ? "revert" : "cherry-pick";
78 }
79
80 static char *get_encoding(const char *message);
81
82 static const char * const *revert_or_cherry_pick_usage(struct replay_opts *opts)
83 {
84         return opts->action == REVERT ? revert_usage : cherry_pick_usage;
85 }
86
87 static int option_parse_x(const struct option *opt,
88                           const char *arg, int unset)
89 {
90         struct replay_opts **opts_ptr = opt->value;
91         struct replay_opts *opts = *opts_ptr;
92
93         if (unset)
94                 return 0;
95
96         ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
97         opts->xopts[opts->xopts_nr++] = xstrdup(arg);
98         return 0;
99 }
100
101 static void verify_opt_compatible(const char *me, const char *base_opt, ...)
102 {
103         const char *this_opt;
104         va_list ap;
105
106         va_start(ap, base_opt);
107         while ((this_opt = va_arg(ap, const char *))) {
108                 if (va_arg(ap, int))
109                         break;
110         }
111         va_end(ap);
112
113         if (this_opt)
114                 die(_("%s: %s cannot be used with %s"), me, this_opt, base_opt);
115 }
116
117 static void verify_opt_mutually_compatible(const char *me, ...)
118 {
119         const char *opt1, *opt2 = NULL;
120         va_list ap;
121
122         va_start(ap, me);
123         while ((opt1 = va_arg(ap, const char *))) {
124                 if (va_arg(ap, int))
125                         break;
126         }
127         if (opt1) {
128                 while ((opt2 = va_arg(ap, const char *))) {
129                         if (va_arg(ap, int))
130                                 break;
131                 }
132         }
133
134         if (opt1 && opt2)
135                 die(_("%s: %s cannot be used with %s"), me, opt1, opt2);
136 }
137
138 static void parse_args(int argc, const char **argv, struct replay_opts *opts)
139 {
140         const char * const * usage_str = revert_or_cherry_pick_usage(opts);
141         const char *me = action_name(opts);
142         int remove_state = 0;
143         int contin = 0;
144         int rollback = 0;
145         struct option options[] = {
146                 OPT_BOOLEAN(0, "quit", &remove_state, "end revert or cherry-pick sequence"),
147                 OPT_BOOLEAN(0, "continue", &contin, "resume revert or cherry-pick sequence"),
148                 OPT_BOOLEAN(0, "abort", &rollback, "cancel revert or cherry-pick sequence"),
149                 OPT_BOOLEAN('n', "no-commit", &opts->no_commit, "don't automatically commit"),
150                 OPT_BOOLEAN('e', "edit", &opts->edit, "edit the commit message"),
151                 OPT_NOOP_NOARG('r', NULL),
152                 OPT_BOOLEAN('s', "signoff", &opts->signoff, "add Signed-off-by:"),
153                 OPT_INTEGER('m', "mainline", &opts->mainline, "parent number"),
154                 OPT_RERERE_AUTOUPDATE(&opts->allow_rerere_auto),
155                 OPT_STRING(0, "strategy", &opts->strategy, "strategy", "merge strategy"),
156                 OPT_CALLBACK('X', "strategy-option", &opts, "option",
157                         "option for merge strategy", option_parse_x),
158                 OPT_END(),
159                 OPT_END(),
160                 OPT_END(),
161         };
162
163         if (opts->action == CHERRY_PICK) {
164                 struct option cp_extra[] = {
165                         OPT_BOOLEAN('x', NULL, &opts->record_origin, "append commit name"),
166                         OPT_BOOLEAN(0, "ff", &opts->allow_ff, "allow fast-forward"),
167                         OPT_END(),
168                 };
169                 if (parse_options_concat(options, ARRAY_SIZE(options), cp_extra))
170                         die(_("program error"));
171         }
172
173         argc = parse_options(argc, argv, NULL, options, usage_str,
174                         PARSE_OPT_KEEP_ARGV0 |
175                         PARSE_OPT_KEEP_UNKNOWN);
176
177         /* Check for incompatible subcommands */
178         verify_opt_mutually_compatible(me,
179                                 "--quit", remove_state,
180                                 "--continue", contin,
181                                 "--abort", rollback,
182                                 NULL);
183
184         /* Set the subcommand */
185         if (remove_state)
186                 opts->subcommand = REPLAY_REMOVE_STATE;
187         else if (contin)
188                 opts->subcommand = REPLAY_CONTINUE;
189         else if (rollback)
190                 opts->subcommand = REPLAY_ROLLBACK;
191         else
192                 opts->subcommand = REPLAY_NONE;
193
194         /* Check for incompatible command line arguments */
195         if (opts->subcommand != REPLAY_NONE) {
196                 char *this_operation;
197                 if (opts->subcommand == REPLAY_REMOVE_STATE)
198                         this_operation = "--quit";
199                 else if (opts->subcommand == REPLAY_CONTINUE)
200                         this_operation = "--continue";
201                 else {
202                         assert(opts->subcommand == REPLAY_ROLLBACK);
203                         this_operation = "--abort";
204                 }
205
206                 verify_opt_compatible(me, this_operation,
207                                 "--no-commit", opts->no_commit,
208                                 "--signoff", opts->signoff,
209                                 "--mainline", opts->mainline,
210                                 "--strategy", opts->strategy ? 1 : 0,
211                                 "--strategy-option", opts->xopts ? 1 : 0,
212                                 "-x", opts->record_origin,
213                                 "--ff", opts->allow_ff,
214                                 NULL);
215         }
216
217         if (opts->allow_ff)
218                 verify_opt_compatible(me, "--ff",
219                                 "--signoff", opts->signoff,
220                                 "--no-commit", opts->no_commit,
221                                 "-x", opts->record_origin,
222                                 "--edit", opts->edit,
223                                 NULL);
224
225         if (opts->subcommand != REPLAY_NONE) {
226                 opts->revs = NULL;
227         } else {
228                 opts->revs = xmalloc(sizeof(*opts->revs));
229                 init_revisions(opts->revs, NULL);
230                 opts->revs->no_walk = 1;
231                 if (argc < 2)
232                         usage_with_options(usage_str, options);
233                 argc = setup_revisions(argc, argv, opts->revs, NULL);
234         }
235
236         if (argc > 1)
237                 usage_with_options(usage_str, options);
238 }
239
240 struct commit_message {
241         char *parent_label;
242         const char *label;
243         const char *subject;
244         char *reencoded_message;
245         const char *message;
246 };
247
248 static int get_message(struct commit *commit, struct commit_message *out)
249 {
250         const char *encoding;
251         const char *abbrev, *subject;
252         int abbrev_len, subject_len;
253         char *q;
254
255         if (!commit->buffer)
256                 return -1;
257         encoding = get_encoding(commit->buffer);
258         if (!encoding)
259                 encoding = "UTF-8";
260         if (!git_commit_encoding)
261                 git_commit_encoding = "UTF-8";
262
263         out->reencoded_message = NULL;
264         out->message = commit->buffer;
265         if (strcmp(encoding, git_commit_encoding))
266                 out->reencoded_message = reencode_string(commit->buffer,
267                                         git_commit_encoding, encoding);
268         if (out->reencoded_message)
269                 out->message = out->reencoded_message;
270
271         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
272         abbrev_len = strlen(abbrev);
273
274         subject_len = find_commit_subject(out->message, &subject);
275
276         out->parent_label = xmalloc(strlen("parent of ") + abbrev_len +
277                               strlen("... ") + subject_len + 1);
278         q = out->parent_label;
279         q = mempcpy(q, "parent of ", strlen("parent of "));
280         out->label = q;
281         q = mempcpy(q, abbrev, abbrev_len);
282         q = mempcpy(q, "... ", strlen("... "));
283         out->subject = q;
284         q = mempcpy(q, subject, subject_len);
285         *q = '\0';
286         return 0;
287 }
288
289 static void free_message(struct commit_message *msg)
290 {
291         free(msg->parent_label);
292         free(msg->reencoded_message);
293 }
294
295 static char *get_encoding(const char *message)
296 {
297         const char *p = message, *eol;
298
299         while (*p && *p != '\n') {
300                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
301                         ; /* do nothing */
302                 if (!prefixcmp(p, "encoding ")) {
303                         char *result = xmalloc(eol - 8 - p);
304                         strlcpy(result, p + 9, eol - 8 - p);
305                         return result;
306                 }
307                 p = eol;
308                 if (*p == '\n')
309                         p++;
310         }
311         return NULL;
312 }
313
314 static void write_cherry_pick_head(struct commit *commit, const char *pseudoref)
315 {
316         const char *filename;
317         int fd;
318         struct strbuf buf = STRBUF_INIT;
319
320         strbuf_addf(&buf, "%s\n", sha1_to_hex(commit->object.sha1));
321
322         filename = git_path("%s", pseudoref);
323         fd = open(filename, O_WRONLY | O_CREAT, 0666);
324         if (fd < 0)
325                 die_errno(_("Could not open '%s' for writing"), filename);
326         if (write_in_full(fd, buf.buf, buf.len) != buf.len || close(fd))
327                 die_errno(_("Could not write to '%s'"), filename);
328         strbuf_release(&buf);
329 }
330
331 static void print_advice(int show_hint)
332 {
333         char *msg = getenv("GIT_CHERRY_PICK_HELP");
334
335         if (msg) {
336                 fprintf(stderr, "%s\n", msg);
337                 /*
338                  * A conflict has occured but the porcelain
339                  * (typically rebase --interactive) wants to take care
340                  * of the commit itself so remove CHERRY_PICK_HEAD
341                  */
342                 unlink(git_path("CHERRY_PICK_HEAD"));
343                 return;
344         }
345
346         if (show_hint) {
347                 advise("after resolving the conflicts, mark the corrected paths");
348                 advise("with 'git add <paths>' or 'git rm <paths>'");
349                 advise("and commit the result with 'git commit'");
350         }
351 }
352
353 static void write_message(struct strbuf *msgbuf, const char *filename)
354 {
355         static struct lock_file msg_file;
356
357         int msg_fd = hold_lock_file_for_update(&msg_file, filename,
358                                                LOCK_DIE_ON_ERROR);
359         if (write_in_full(msg_fd, msgbuf->buf, msgbuf->len) < 0)
360                 die_errno(_("Could not write to %s"), filename);
361         strbuf_release(msgbuf);
362         if (commit_lock_file(&msg_file) < 0)
363                 die(_("Error wrapping up %s"), filename);
364 }
365
366 static struct tree *empty_tree(void)
367 {
368         return lookup_tree((const unsigned char *)EMPTY_TREE_SHA1_BIN);
369 }
370
371 static int error_dirty_index(struct replay_opts *opts)
372 {
373         if (read_cache_unmerged())
374                 return error_resolve_conflict(action_name(opts));
375
376         /* Different translation strings for cherry-pick and revert */
377         if (opts->action == CHERRY_PICK)
378                 error(_("Your local changes would be overwritten by cherry-pick."));
379         else
380                 error(_("Your local changes would be overwritten by revert."));
381
382         if (advice_commit_before_merge)
383                 advise(_("Commit your changes or stash them to proceed."));
384         return -1;
385 }
386
387 static int fast_forward_to(const unsigned char *to, const unsigned char *from)
388 {
389         struct ref_lock *ref_lock;
390
391         read_cache();
392         if (checkout_fast_forward(from, to))
393                 exit(1); /* the callee should have complained already */
394         ref_lock = lock_any_ref_for_update("HEAD", from, 0);
395         return write_ref_sha1(ref_lock, to, "cherry-pick");
396 }
397
398 static int do_recursive_merge(struct commit *base, struct commit *next,
399                               const char *base_label, const char *next_label,
400                               unsigned char *head, struct strbuf *msgbuf,
401                               struct replay_opts *opts)
402 {
403         struct merge_options o;
404         struct tree *result, *next_tree, *base_tree, *head_tree;
405         int clean, index_fd;
406         const char **xopt;
407         static struct lock_file index_lock;
408
409         index_fd = hold_locked_index(&index_lock, 1);
410
411         read_cache();
412
413         init_merge_options(&o);
414         o.ancestor = base ? base_label : "(empty tree)";
415         o.branch1 = "HEAD";
416         o.branch2 = next ? next_label : "(empty tree)";
417
418         head_tree = parse_tree_indirect(head);
419         next_tree = next ? next->tree : empty_tree();
420         base_tree = base ? base->tree : empty_tree();
421
422         for (xopt = opts->xopts; xopt != opts->xopts + opts->xopts_nr; xopt++)
423                 parse_merge_opt(&o, *xopt);
424
425         clean = merge_trees(&o,
426                             head_tree,
427                             next_tree, base_tree, &result);
428
429         if (active_cache_changed &&
430             (write_cache(index_fd, active_cache, active_nr) ||
431              commit_locked_index(&index_lock)))
432                 /* TRANSLATORS: %s will be "revert" or "cherry-pick" */
433                 die(_("%s: Unable to write new index file"), action_name(opts));
434         rollback_lock_file(&index_lock);
435
436         if (!clean) {
437                 int i;
438                 strbuf_addstr(msgbuf, "\nConflicts:\n\n");
439                 for (i = 0; i < active_nr;) {
440                         struct cache_entry *ce = active_cache[i++];
441                         if (ce_stage(ce)) {
442                                 strbuf_addch(msgbuf, '\t');
443                                 strbuf_addstr(msgbuf, ce->name);
444                                 strbuf_addch(msgbuf, '\n');
445                                 while (i < active_nr && !strcmp(ce->name,
446                                                 active_cache[i]->name))
447                                         i++;
448                         }
449                 }
450         }
451
452         return !clean;
453 }
454
455 /*
456  * If we are cherry-pick, and if the merge did not result in
457  * hand-editing, we will hit this commit and inherit the original
458  * author date and name.
459  * If we are revert, or if our cherry-pick results in a hand merge,
460  * we had better say that the current user is responsible for that.
461  */
462 static int run_git_commit(const char *defmsg, struct replay_opts *opts)
463 {
464         /* 6 is max possible length of our args array including NULL */
465         const char *args[6];
466         int i = 0;
467
468         args[i++] = "commit";
469         args[i++] = "-n";
470         if (opts->signoff)
471                 args[i++] = "-s";
472         if (!opts->edit) {
473                 args[i++] = "-F";
474                 args[i++] = defmsg;
475         }
476         args[i] = NULL;
477
478         return run_command_v_opt(args, RUN_GIT_CMD);
479 }
480
481 static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
482 {
483         unsigned char head[20];
484         struct commit *base, *next, *parent;
485         const char *base_label, *next_label;
486         struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
487         char *defmsg = NULL;
488         struct strbuf msgbuf = STRBUF_INIT;
489         int res;
490
491         if (opts->no_commit) {
492                 /*
493                  * We do not intend to commit immediately.  We just want to
494                  * merge the differences in, so let's compute the tree
495                  * that represents the "current" state for merge-recursive
496                  * to work on.
497                  */
498                 if (write_cache_as_tree(head, 0, NULL))
499                         die (_("Your index file is unmerged."));
500         } else {
501                 if (get_sha1("HEAD", head))
502                         return error(_("You do not have a valid HEAD"));
503                 if (index_differs_from("HEAD", 0))
504                         return error_dirty_index(opts);
505         }
506         discard_cache();
507
508         if (!commit->parents) {
509                 parent = NULL;
510         }
511         else if (commit->parents->next) {
512                 /* Reverting or cherry-picking a merge commit */
513                 int cnt;
514                 struct commit_list *p;
515
516                 if (!opts->mainline)
517                         return error(_("Commit %s is a merge but no -m option was given."),
518                                 sha1_to_hex(commit->object.sha1));
519
520                 for (cnt = 1, p = commit->parents;
521                      cnt != opts->mainline && p;
522                      cnt++)
523                         p = p->next;
524                 if (cnt != opts->mainline || !p)
525                         return error(_("Commit %s does not have parent %d"),
526                                 sha1_to_hex(commit->object.sha1), opts->mainline);
527                 parent = p->item;
528         } else if (0 < opts->mainline)
529                 return error(_("Mainline was specified but commit %s is not a merge."),
530                         sha1_to_hex(commit->object.sha1));
531         else
532                 parent = commit->parents->item;
533
534         if (opts->allow_ff && parent && !hashcmp(parent->object.sha1, head))
535                 return fast_forward_to(commit->object.sha1, head);
536
537         if (parent && parse_commit(parent) < 0)
538                 /* TRANSLATORS: The first %s will be "revert" or
539                    "cherry-pick", the second %s a SHA1 */
540                 return error(_("%s: cannot parse parent commit %s"),
541                         action_name(opts), sha1_to_hex(parent->object.sha1));
542
543         if (get_message(commit, &msg) != 0)
544                 return error(_("Cannot get commit message for %s"),
545                         sha1_to_hex(commit->object.sha1));
546
547         /*
548          * "commit" is an existing commit.  We would want to apply
549          * the difference it introduces since its first parent "prev"
550          * on top of the current HEAD if we are cherry-pick.  Or the
551          * reverse of it if we are revert.
552          */
553
554         defmsg = git_pathdup("MERGE_MSG");
555
556         if (opts->action == REVERT) {
557                 base = commit;
558                 base_label = msg.label;
559                 next = parent;
560                 next_label = msg.parent_label;
561                 strbuf_addstr(&msgbuf, "Revert \"");
562                 strbuf_addstr(&msgbuf, msg.subject);
563                 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
564                 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
565
566                 if (commit->parents && commit->parents->next) {
567                         strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
568                         strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
569                 }
570                 strbuf_addstr(&msgbuf, ".\n");
571         } else {
572                 const char *p;
573
574                 base = parent;
575                 base_label = msg.parent_label;
576                 next = commit;
577                 next_label = msg.label;
578
579                 /*
580                  * Append the commit log message to msgbuf; it starts
581                  * after the tree, parent, author, committer
582                  * information followed by "\n\n".
583                  */
584                 p = strstr(msg.message, "\n\n");
585                 if (p) {
586                         p += 2;
587                         strbuf_addstr(&msgbuf, p);
588                 }
589
590                 if (opts->record_origin) {
591                         strbuf_addstr(&msgbuf, "(cherry picked from commit ");
592                         strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
593                         strbuf_addstr(&msgbuf, ")\n");
594                 }
595         }
596
597         if (!opts->strategy || !strcmp(opts->strategy, "recursive") || opts->action == REVERT) {
598                 res = do_recursive_merge(base, next, base_label, next_label,
599                                          head, &msgbuf, opts);
600                 write_message(&msgbuf, defmsg);
601         } else {
602                 struct commit_list *common = NULL;
603                 struct commit_list *remotes = NULL;
604
605                 write_message(&msgbuf, defmsg);
606
607                 commit_list_insert(base, &common);
608                 commit_list_insert(next, &remotes);
609                 res = try_merge_command(opts->strategy, opts->xopts_nr, opts->xopts,
610                                         common, sha1_to_hex(head), remotes);
611                 free_commit_list(common);
612                 free_commit_list(remotes);
613         }
614
615         /*
616          * If the merge was clean or if it failed due to conflict, we write
617          * CHERRY_PICK_HEAD for the subsequent invocation of commit to use.
618          * However, if the merge did not even start, then we don't want to
619          * write it at all.
620          */
621         if (opts->action == CHERRY_PICK && !opts->no_commit && (res == 0 || res == 1))
622                 write_cherry_pick_head(commit, "CHERRY_PICK_HEAD");
623         if (opts->action == REVERT && ((opts->no_commit && res == 0) || res == 1))
624                 write_cherry_pick_head(commit, "REVERT_HEAD");
625
626         if (res) {
627                 error(opts->action == REVERT
628                       ? _("could not revert %s... %s")
629                       : _("could not apply %s... %s"),
630                       find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV),
631                       msg.subject);
632                 print_advice(res == 1);
633                 rerere(opts->allow_rerere_auto);
634         } else {
635                 if (!opts->no_commit)
636                         res = run_git_commit(defmsg, opts);
637         }
638
639         free_message(&msg);
640         free(defmsg);
641
642         return res;
643 }
644
645 static void prepare_revs(struct replay_opts *opts)
646 {
647         if (opts->action != REVERT)
648                 opts->revs->reverse ^= 1;
649
650         if (prepare_revision_walk(opts->revs))
651                 die(_("revision walk setup failed"));
652
653         if (!opts->revs->commits)
654                 die(_("empty commit set passed"));
655 }
656
657 static void read_and_refresh_cache(struct replay_opts *opts)
658 {
659         static struct lock_file index_lock;
660         int index_fd = hold_locked_index(&index_lock, 0);
661         if (read_index_preload(&the_index, NULL) < 0)
662                 die(_("git %s: failed to read the index"), action_name(opts));
663         refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
664         if (the_index.cache_changed) {
665                 if (write_index(&the_index, index_fd) ||
666                     commit_locked_index(&index_lock))
667                         die(_("git %s: failed to refresh the index"), action_name(opts));
668         }
669         rollback_lock_file(&index_lock);
670 }
671
672 /*
673  * Append a commit to the end of the commit_list.
674  *
675  * next starts by pointing to the variable that holds the head of an
676  * empty commit_list, and is updated to point to the "next" field of
677  * the last item on the list as new commits are appended.
678  *
679  * Usage example:
680  *
681  *     struct commit_list *list;
682  *     struct commit_list **next = &list;
683  *
684  *     next = commit_list_append(c1, next);
685  *     next = commit_list_append(c2, next);
686  *     assert(commit_list_count(list) == 2);
687  *     return list;
688  */
689 static struct commit_list **commit_list_append(struct commit *commit,
690                                                struct commit_list **next)
691 {
692         struct commit_list *new = xmalloc(sizeof(struct commit_list));
693         new->item = commit;
694         *next = new;
695         new->next = NULL;
696         return &new->next;
697 }
698
699 static int format_todo(struct strbuf *buf, struct commit_list *todo_list,
700                 struct replay_opts *opts)
701 {
702         struct commit_list *cur = NULL;
703         const char *sha1_abbrev = NULL;
704         const char *action_str = opts->action == REVERT ? "revert" : "pick";
705         const char *subject;
706         int subject_len;
707
708         for (cur = todo_list; cur; cur = cur->next) {
709                 sha1_abbrev = find_unique_abbrev(cur->item->object.sha1, DEFAULT_ABBREV);
710                 subject_len = find_commit_subject(cur->item->buffer, &subject);
711                 strbuf_addf(buf, "%s %s %.*s\n", action_str, sha1_abbrev,
712                         subject_len, subject);
713         }
714         return 0;
715 }
716
717 static struct commit *parse_insn_line(char *bol, char *eol, struct replay_opts *opts)
718 {
719         unsigned char commit_sha1[20];
720         enum replay_action action;
721         char *end_of_object_name;
722         int saved, status, padding;
723
724         if (!prefixcmp(bol, "pick")) {
725                 action = CHERRY_PICK;
726                 bol += strlen("pick");
727         } else if (!prefixcmp(bol, "revert")) {
728                 action = REVERT;
729                 bol += strlen("revert");
730         } else
731                 return NULL;
732
733         /* Eat up extra spaces/ tabs before object name */
734         padding = strspn(bol, " \t");
735         if (!padding)
736                 return NULL;
737         bol += padding;
738
739         end_of_object_name = bol + strcspn(bol, " \t\n");
740         saved = *end_of_object_name;
741         *end_of_object_name = '\0';
742         status = get_sha1(bol, commit_sha1);
743         *end_of_object_name = saved;
744
745         /*
746          * Verify that the action matches up with the one in
747          * opts; we don't support arbitrary instructions
748          */
749         if (action != opts->action) {
750                 const char *action_str;
751                 action_str = action == REVERT ? "revert" : "cherry-pick";
752                 error(_("Cannot %s during a %s"), action_str, action_name(opts));
753                 return NULL;
754         }
755
756         if (status < 0)
757                 return NULL;
758
759         return lookup_commit_reference(commit_sha1);
760 }
761
762 static int parse_insn_buffer(char *buf, struct commit_list **todo_list,
763                         struct replay_opts *opts)
764 {
765         struct commit_list **next = todo_list;
766         struct commit *commit;
767         char *p = buf;
768         int i;
769
770         for (i = 1; *p; i++) {
771                 char *eol = strchrnul(p, '\n');
772                 commit = parse_insn_line(p, eol, opts);
773                 if (!commit)
774                         return error(_("Could not parse line %d."), i);
775                 next = commit_list_append(commit, next);
776                 p = *eol ? eol + 1 : eol;
777         }
778         if (!*todo_list)
779                 return error(_("No commits parsed."));
780         return 0;
781 }
782
783 static void read_populate_todo(struct commit_list **todo_list,
784                         struct replay_opts *opts)
785 {
786         const char *todo_file = git_path(SEQ_TODO_FILE);
787         struct strbuf buf = STRBUF_INIT;
788         int fd, res;
789
790         fd = open(todo_file, O_RDONLY);
791         if (fd < 0)
792                 die_errno(_("Could not open %s"), todo_file);
793         if (strbuf_read(&buf, fd, 0) < 0) {
794                 close(fd);
795                 strbuf_release(&buf);
796                 die(_("Could not read %s."), todo_file);
797         }
798         close(fd);
799
800         res = parse_insn_buffer(buf.buf, todo_list, opts);
801         strbuf_release(&buf);
802         if (res)
803                 die(_("Unusable instruction sheet: %s"), todo_file);
804 }
805
806 static int populate_opts_cb(const char *key, const char *value, void *data)
807 {
808         struct replay_opts *opts = data;
809         int error_flag = 1;
810
811         if (!value)
812                 error_flag = 0;
813         else if (!strcmp(key, "options.no-commit"))
814                 opts->no_commit = git_config_bool_or_int(key, value, &error_flag);
815         else if (!strcmp(key, "options.edit"))
816                 opts->edit = git_config_bool_or_int(key, value, &error_flag);
817         else if (!strcmp(key, "options.signoff"))
818                 opts->signoff = git_config_bool_or_int(key, value, &error_flag);
819         else if (!strcmp(key, "options.record-origin"))
820                 opts->record_origin = git_config_bool_or_int(key, value, &error_flag);
821         else if (!strcmp(key, "options.allow-ff"))
822                 opts->allow_ff = git_config_bool_or_int(key, value, &error_flag);
823         else if (!strcmp(key, "options.mainline"))
824                 opts->mainline = git_config_int(key, value);
825         else if (!strcmp(key, "options.strategy"))
826                 git_config_string(&opts->strategy, key, value);
827         else if (!strcmp(key, "options.strategy-option")) {
828                 ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
829                 opts->xopts[opts->xopts_nr++] = xstrdup(value);
830         } else
831                 return error(_("Invalid key: %s"), key);
832
833         if (!error_flag)
834                 return error(_("Invalid value for %s: %s"), key, value);
835
836         return 0;
837 }
838
839 static void read_populate_opts(struct replay_opts **opts_ptr)
840 {
841         const char *opts_file = git_path(SEQ_OPTS_FILE);
842
843         if (!file_exists(opts_file))
844                 return;
845         if (git_config_from_file(populate_opts_cb, opts_file, *opts_ptr) < 0)
846                 die(_("Malformed options sheet: %s"), opts_file);
847 }
848
849 static void walk_revs_populate_todo(struct commit_list **todo_list,
850                                 struct replay_opts *opts)
851 {
852         struct commit *commit;
853         struct commit_list **next;
854
855         prepare_revs(opts);
856
857         next = todo_list;
858         while ((commit = get_revision(opts->revs)))
859                 next = commit_list_append(commit, next);
860 }
861
862 static int create_seq_dir(void)
863 {
864         const char *seq_dir = git_path(SEQ_DIR);
865
866         if (file_exists(seq_dir)) {
867                 error(_("a cherry-pick or revert is already in progress"));
868                 advise(_("try \"git cherry-pick (--continue | --quit | --abort)\""));
869                 return -1;
870         }
871         else if (mkdir(seq_dir, 0777) < 0)
872                 die_errno(_("Could not create sequencer directory %s"), seq_dir);
873         return 0;
874 }
875
876 static void save_head(const char *head)
877 {
878         const char *head_file = git_path(SEQ_HEAD_FILE);
879         static struct lock_file head_lock;
880         struct strbuf buf = STRBUF_INIT;
881         int fd;
882
883         fd = hold_lock_file_for_update(&head_lock, head_file, LOCK_DIE_ON_ERROR);
884         strbuf_addf(&buf, "%s\n", head);
885         if (write_in_full(fd, buf.buf, buf.len) < 0)
886                 die_errno(_("Could not write to %s"), head_file);
887         if (commit_lock_file(&head_lock) < 0)
888                 die(_("Error wrapping up %s."), head_file);
889 }
890
891 static int reset_for_rollback(const unsigned char *sha1)
892 {
893         const char *argv[4];    /* reset --merge <arg> + NULL */
894         argv[0] = "reset";
895         argv[1] = "--merge";
896         argv[2] = sha1_to_hex(sha1);
897         argv[3] = NULL;
898         return run_command_v_opt(argv, RUN_GIT_CMD);
899 }
900
901 static int rollback_single_pick(void)
902 {
903         unsigned char head_sha1[20];
904
905         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
906             !file_exists(git_path("REVERT_HEAD")))
907                 return error(_("no cherry-pick or revert in progress"));
908         if (read_ref_full("HEAD", head_sha1, 0, NULL))
909                 return error(_("cannot resolve HEAD"));
910         if (is_null_sha1(head_sha1))
911                 return error(_("cannot abort from a branch yet to be born"));
912         return reset_for_rollback(head_sha1);
913 }
914
915 static int sequencer_rollback(struct replay_opts *opts)
916 {
917         const char *filename;
918         FILE *f;
919         unsigned char sha1[20];
920         struct strbuf buf = STRBUF_INIT;
921
922         filename = git_path(SEQ_HEAD_FILE);
923         f = fopen(filename, "r");
924         if (!f && errno == ENOENT) {
925                 /*
926                  * There is no multiple-cherry-pick in progress.
927                  * If CHERRY_PICK_HEAD or REVERT_HEAD indicates
928                  * a single-cherry-pick in progress, abort that.
929                  */
930                 return rollback_single_pick();
931         }
932         if (!f)
933                 return error(_("cannot open %s: %s"), filename,
934                                                 strerror(errno));
935         if (strbuf_getline(&buf, f, '\n')) {
936                 error(_("cannot read %s: %s"), filename, ferror(f) ?
937                         strerror(errno) : _("unexpected end of file"));
938                 fclose(f);
939                 goto fail;
940         }
941         fclose(f);
942         if (get_sha1_hex(buf.buf, sha1) || buf.buf[40] != '\0') {
943                 error(_("stored pre-cherry-pick HEAD file '%s' is corrupt"),
944                         filename);
945                 goto fail;
946         }
947         if (reset_for_rollback(sha1))
948                 goto fail;
949         remove_sequencer_state();
950         strbuf_release(&buf);
951         return 0;
952 fail:
953         strbuf_release(&buf);
954         return -1;
955 }
956
957 static void save_todo(struct commit_list *todo_list, struct replay_opts *opts)
958 {
959         const char *todo_file = git_path(SEQ_TODO_FILE);
960         static struct lock_file todo_lock;
961         struct strbuf buf = STRBUF_INIT;
962         int fd;
963
964         fd = hold_lock_file_for_update(&todo_lock, todo_file, LOCK_DIE_ON_ERROR);
965         if (format_todo(&buf, todo_list, opts) < 0)
966                 die(_("Could not format %s."), todo_file);
967         if (write_in_full(fd, buf.buf, buf.len) < 0) {
968                 strbuf_release(&buf);
969                 die_errno(_("Could not write to %s"), todo_file);
970         }
971         if (commit_lock_file(&todo_lock) < 0) {
972                 strbuf_release(&buf);
973                 die(_("Error wrapping up %s."), todo_file);
974         }
975         strbuf_release(&buf);
976 }
977
978 static void save_opts(struct replay_opts *opts)
979 {
980         const char *opts_file = git_path(SEQ_OPTS_FILE);
981
982         if (opts->no_commit)
983                 git_config_set_in_file(opts_file, "options.no-commit", "true");
984         if (opts->edit)
985                 git_config_set_in_file(opts_file, "options.edit", "true");
986         if (opts->signoff)
987                 git_config_set_in_file(opts_file, "options.signoff", "true");
988         if (opts->record_origin)
989                 git_config_set_in_file(opts_file, "options.record-origin", "true");
990         if (opts->allow_ff)
991                 git_config_set_in_file(opts_file, "options.allow-ff", "true");
992         if (opts->mainline) {
993                 struct strbuf buf = STRBUF_INIT;
994                 strbuf_addf(&buf, "%d", opts->mainline);
995                 git_config_set_in_file(opts_file, "options.mainline", buf.buf);
996                 strbuf_release(&buf);
997         }
998         if (opts->strategy)
999                 git_config_set_in_file(opts_file, "options.strategy", opts->strategy);
1000         if (opts->xopts) {
1001                 int i;
1002                 for (i = 0; i < opts->xopts_nr; i++)
1003                         git_config_set_multivar_in_file(opts_file,
1004                                                         "options.strategy-option",
1005                                                         opts->xopts[i], "^$", 0);
1006         }
1007 }
1008
1009 static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
1010 {
1011         struct commit_list *cur;
1012         int res;
1013
1014         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
1015         if (opts->allow_ff)
1016                 assert(!(opts->signoff || opts->no_commit ||
1017                                 opts->record_origin || opts->edit));
1018         read_and_refresh_cache(opts);
1019
1020         for (cur = todo_list; cur; cur = cur->next) {
1021                 save_todo(cur, opts);
1022                 res = do_pick_commit(cur->item, opts);
1023                 if (res)
1024                         return res;
1025         }
1026
1027         /*
1028          * Sequence of picks finished successfully; cleanup by
1029          * removing the .git/sequencer directory
1030          */
1031         remove_sequencer_state();
1032         return 0;
1033 }
1034
1035 static int continue_single_pick(void)
1036 {
1037         const char *argv[] = { "commit", NULL };
1038
1039         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
1040             !file_exists(git_path("REVERT_HEAD")))
1041                 return error(_("no cherry-pick or revert in progress"));
1042         return run_command_v_opt(argv, RUN_GIT_CMD);
1043 }
1044
1045 static int sequencer_continue(struct replay_opts *opts)
1046 {
1047         struct commit_list *todo_list = NULL;
1048
1049         if (!file_exists(git_path(SEQ_TODO_FILE)))
1050                 return continue_single_pick();
1051         read_populate_opts(&opts);
1052         read_populate_todo(&todo_list, opts);
1053
1054         /* Verify that the conflict has been resolved */
1055         if (file_exists(git_path("CHERRY_PICK_HEAD")) ||
1056             file_exists(git_path("REVERT_HEAD"))) {
1057                 int ret = continue_single_pick();
1058                 if (ret)
1059                         return ret;
1060         }
1061         if (index_differs_from("HEAD", 0))
1062                 return error_dirty_index(opts);
1063         todo_list = todo_list->next;
1064         return pick_commits(todo_list, opts);
1065 }
1066
1067 static int single_pick(struct commit *cmit, struct replay_opts *opts)
1068 {
1069         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
1070         return do_pick_commit(cmit, opts);
1071 }
1072
1073 static int pick_revisions(struct replay_opts *opts)
1074 {
1075         struct commit_list *todo_list = NULL;
1076         unsigned char sha1[20];
1077
1078         if (opts->subcommand == REPLAY_NONE)
1079                 assert(opts->revs);
1080
1081         read_and_refresh_cache(opts);
1082
1083         /*
1084          * Decide what to do depending on the arguments; a fresh
1085          * cherry-pick should be handled differently from an existing
1086          * one that is being continued
1087          */
1088         if (opts->subcommand == REPLAY_REMOVE_STATE) {
1089                 remove_sequencer_state();
1090                 return 0;
1091         }
1092         if (opts->subcommand == REPLAY_ROLLBACK)
1093                 return sequencer_rollback(opts);
1094         if (opts->subcommand == REPLAY_CONTINUE)
1095                 return sequencer_continue(opts);
1096
1097         /*
1098          * If we were called as "git cherry-pick <commit>", just
1099          * cherry-pick/revert it, set CHERRY_PICK_HEAD /
1100          * REVERT_HEAD, and don't touch the sequencer state.
1101          * This means it is possible to cherry-pick in the middle
1102          * of a cherry-pick sequence.
1103          */
1104         if (opts->revs->cmdline.nr == 1 &&
1105             opts->revs->cmdline.rev->whence == REV_CMD_REV &&
1106             opts->revs->no_walk &&
1107             !opts->revs->cmdline.rev->flags) {
1108                 struct commit *cmit;
1109                 if (prepare_revision_walk(opts->revs))
1110                         die(_("revision walk setup failed"));
1111                 cmit = get_revision(opts->revs);
1112                 if (!cmit || get_revision(opts->revs))
1113                         die("BUG: expected exactly one commit from walk");
1114                 return single_pick(cmit, opts);
1115         }
1116
1117         /*
1118          * Start a new cherry-pick/ revert sequence; but
1119          * first, make sure that an existing one isn't in
1120          * progress
1121          */
1122
1123         walk_revs_populate_todo(&todo_list, opts);
1124         if (create_seq_dir() < 0)
1125                 return -1;
1126         if (get_sha1("HEAD", sha1)) {
1127                 if (opts->action == REVERT)
1128                         return error(_("Can't revert as initial commit"));
1129                 return error(_("Can't cherry-pick into empty head"));
1130         }
1131         save_head(sha1_to_hex(sha1));
1132         save_opts(opts);
1133         return pick_commits(todo_list, opts);
1134 }
1135
1136 int cmd_revert(int argc, const char **argv, const char *prefix)
1137 {
1138         struct replay_opts opts;
1139         int res;
1140
1141         memset(&opts, 0, sizeof(opts));
1142         if (isatty(0))
1143                 opts.edit = 1;
1144         opts.action = REVERT;
1145         git_config(git_default_config, NULL);
1146         parse_args(argc, argv, &opts);
1147         res = pick_revisions(&opts);
1148         if (res < 0)
1149                 die(_("revert failed"));
1150         return res;
1151 }
1152
1153 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
1154 {
1155         struct replay_opts opts;
1156         int res;
1157
1158         memset(&opts, 0, sizeof(opts));
1159         opts.action = CHERRY_PICK;
1160         git_config(git_default_config, NULL);
1161         parse_args(argc, argv, &opts);
1162         res = pick_revisions(&opts);
1163         if (res < 0)
1164                 die(_("cherry-pick failed"));
1165         return res;
1166 }