git.oblomov.eu Git - git/blob - sequencer.c

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