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
  22 static void remove_sequencer_state(void)
  23 {
  24         struct strbuf seq_dir = STRBUF_INIT;
  25
  26         strbuf_addf(&seq_dir, "%s", git_path(SEQ_DIR));
  27         remove_dir_recursively(&seq_dir, 0);
  28         strbuf_release(&seq_dir);
  29 }
  30
  31 static const char *action_name(const struct replay_opts *opts)
  32 {
  33         return opts->action == REPLAY_REVERT ? "revert" : "cherry-pick";
  34 }
  35
  36 static char *get_encoding(const char *message);
  37
  38 struct commit_message {
  39         char *parent_label;
  40         const char *label;
  41         const char *subject;
  42         char *reencoded_message;
  43         const char *message;
  44 };
  45
  46 static int get_message(struct commit *commit, struct commit_message *out)
  47 {
  48         const char *encoding;
  49         const char *abbrev, *subject;
  50         int abbrev_len, subject_len;
  51         char *q;
  52
  53         if (!commit->buffer)
  54                 return -1;
  55         encoding = get_encoding(commit->buffer);
  56         if (!encoding)
  57                 encoding = "UTF-8";
  58         if (!git_commit_encoding)
  59                 git_commit_encoding = "UTF-8";
  60
  61         out->reencoded_message = NULL;
  62         out->message = commit->buffer;
  63         if (same_encoding(encoding, git_commit_encoding))
  64                 out->reencoded_message = reencode_string(commit->buffer,
  65                                         git_commit_encoding, encoding);
  66         if (out->reencoded_message)
  67                 out->message = out->reencoded_message;
  68
  69         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
  70         abbrev_len = strlen(abbrev);
  71
  72         subject_len = find_commit_subject(out->message, &subject);
  73
  74         out->parent_label = xmalloc(strlen("parent of ") + abbrev_len +
  75                               strlen("... ") + subject_len + 1);
  76         q = out->parent_label;
  77         q = mempcpy(q, "parent of ", strlen("parent of "));
  78         out->label = q;
  79         q = mempcpy(q, abbrev, abbrev_len);
  80         q = mempcpy(q, "... ", strlen("... "));
  81         out->subject = q;
  82         q = mempcpy(q, subject, subject_len);
  83         *q = '\0';
  84         return 0;
  85 }
  86
  87 static void free_message(struct commit_message *msg)
  88 {
  89         free(msg->parent_label);
  90         free(msg->reencoded_message);
  91 }
  92
  93 static char *get_encoding(const char *message)
  94 {
  95         const char *p = message, *eol;
  96
  97         while (*p && *p != '\n') {
  98                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
  99                         ; /* do nothing */
 100                 if (!prefixcmp(p, "encoding ")) {
 101                         char *result = xmalloc(eol - 8 - p);
 102                         strlcpy(result, p + 9, eol - 8 - p);
 103                         return result;
 104                 }
 105                 p = eol;
 106                 if (*p == '\n')
 107                         p++;
 108         }
 109         return NULL;
 110 }
 111
 112 static void write_cherry_pick_head(struct commit *commit, const char *pseudoref)
 113 {
 114         const char *filename;
 115         int fd;
 116         struct strbuf buf = STRBUF_INIT;
 117
 118         strbuf_addf(&buf, "%s\n", sha1_to_hex(commit->object.sha1));
 119
 120         filename = git_path("%s", pseudoref);
 121         fd = open(filename, O_WRONLY | O_CREAT, 0666);
 122         if (fd < 0)
 123                 die_errno(_("Could not open '%s' for writing"), filename);
 124         if (write_in_full(fd, buf.buf, buf.len) != buf.len || close(fd))
 125                 die_errno(_("Could not write to '%s'"), filename);
 126         strbuf_release(&buf);
 127 }
 128
 129 static void print_advice(int show_hint, struct replay_opts *opts)
 130 {
 131         char *msg = getenv("GIT_CHERRY_PICK_HELP");
 132
 133         if (msg) {
 134                 fprintf(stderr, "%s\n", msg);
 135                 /*
 136                  * A conflict has occured but the porcelain
 137                  * (typically rebase --interactive) wants to take care
 138                  * of the commit itself so remove CHERRY_PICK_HEAD
 139                  */
 140                 unlink(git_path("CHERRY_PICK_HEAD"));
 141                 return;
 142         }
 143
 144         if (show_hint) {
 145                 if (opts->no_commit)
 146                         advise(_("after resolving the conflicts, mark the corrected paths\n"
 147                                  "with 'git add <paths>' or 'git rm <paths>'"));
 148                 else
 149                         advise(_("after resolving the conflicts, mark the corrected paths\n"
 150                                  "with 'git add <paths>' or 'git rm <paths>'\n"
 151                                  "and commit the result with 'git commit'"));
 152         }
 153 }
 154
 155 static void write_message(struct strbuf *msgbuf, const char *filename)
 156 {
 157         static struct lock_file msg_file;
 158
 159         int msg_fd = hold_lock_file_for_update(&msg_file, filename,
 160                                                LOCK_DIE_ON_ERROR);
 161         if (write_in_full(msg_fd, msgbuf->buf, msgbuf->len) < 0)
 162                 die_errno(_("Could not write to %s"), filename);
 163         strbuf_release(msgbuf);
 164         if (commit_lock_file(&msg_file) < 0)
 165                 die(_("Error wrapping up %s"), filename);
 166 }
 167
 168 static struct tree *empty_tree(void)
 169 {
 170         return lookup_tree(EMPTY_TREE_SHA1_BIN);
 171 }
 172
 173 static int error_dirty_index(struct replay_opts *opts)
 174 {
 175         if (read_cache_unmerged())
 176                 return error_resolve_conflict(action_name(opts));
 177
 178         /* Different translation strings for cherry-pick and revert */
 179         if (opts->action == REPLAY_PICK)
 180                 error(_("Your local changes would be overwritten by cherry-pick."));
 181         else
 182                 error(_("Your local changes would be overwritten by revert."));
 183
 184         if (advice_commit_before_merge)
 185                 advise(_("Commit your changes or stash them to proceed."));
 186         return -1;
 187 }
 188
 189 static int fast_forward_to(const unsigned char *to, const unsigned char *from,
 190                            int unborn)
 191 {
 192         struct ref_lock *ref_lock;
 193
 194         read_cache();
 195         if (checkout_fast_forward(from, to, 1))
 196                 exit(1); /* the callee should have complained already */
 197         ref_lock = lock_any_ref_for_update("HEAD", unborn ? null_sha1 : from, 0);
 198         return write_ref_sha1(ref_lock, to, "cherry-pick");
 199 }
 200
 201 static int do_recursive_merge(struct commit *base, struct commit *next,
 202                               const char *base_label, const char *next_label,
 203                               unsigned char *head, struct strbuf *msgbuf,
 204                               struct replay_opts *opts)
 205 {
 206         struct merge_options o;
 207         struct tree *result, *next_tree, *base_tree, *head_tree;
 208         int clean, index_fd;
 209         const char **xopt;
 210         static struct lock_file index_lock;
 211
 212         index_fd = hold_locked_index(&index_lock, 1);
 213
 214         read_cache();
 215
 216         init_merge_options(&o);
 217         o.ancestor = base ? base_label : "(empty tree)";
 218         o.branch1 = "HEAD";
 219         o.branch2 = next ? next_label : "(empty tree)";
 220
 221         head_tree = parse_tree_indirect(head);
 222         next_tree = next ? next->tree : empty_tree();
 223         base_tree = base ? base->tree : empty_tree();
 224
 225         for (xopt = opts->xopts; xopt != opts->xopts + opts->xopts_nr; xopt++)
 226                 parse_merge_opt(&o, *xopt);
 227
 228         clean = merge_trees(&o,
 229                             head_tree,
 230                             next_tree, base_tree, &result);
 231
 232         if (active_cache_changed &&
 233             (write_cache(index_fd, active_cache, active_nr) ||
 234              commit_locked_index(&index_lock)))
 235                 /* TRANSLATORS: %s will be "revert" or "cherry-pick" */
 236                 die(_("%s: Unable to write new index file"), action_name(opts));
 237         rollback_lock_file(&index_lock);
 238
 239         if (opts->signoff)
 240                 append_signoff(msgbuf, 0);
 241
 242         if (!clean) {
 243                 int i;
 244                 strbuf_addstr(msgbuf, "\nConflicts:\n");
 245                 for (i = 0; i < active_nr;) {
 246                         struct cache_entry *ce = active_cache[i++];
 247                         if (ce_stage(ce)) {
 248                                 strbuf_addch(msgbuf, '\t');
 249                                 strbuf_addstr(msgbuf, ce->name);
 250                                 strbuf_addch(msgbuf, '\n');
 251                                 while (i < active_nr && !strcmp(ce->name,
 252                                                 active_cache[i]->name))
 253                                         i++;
 254                         }
 255                 }
 256         }
 257
 258         return !clean;
 259 }
 260
 261 static int is_index_unchanged(void)
 262 {
 263         unsigned char head_sha1[20];
 264         struct commit *head_commit;
 265
 266         if (!resolve_ref_unsafe("HEAD", head_sha1, 1, NULL))
 267                 return error(_("Could not resolve HEAD commit\n"));
 268
 269         head_commit = lookup_commit(head_sha1);
 270
 271         /*
 272          * If head_commit is NULL, check_commit, called from
 273          * lookup_commit, would have indicated that head_commit is not
 274          * a commit object already.  parse_commit() will return failure
 275          * without further complaints in such a case.  Otherwise, if
 276          * the commit is invalid, parse_commit() will complain.  So
 277          * there is nothing for us to say here.  Just return failure.
 278          */
 279         if (parse_commit(head_commit))
 280                 return -1;
 281
 282         if (!active_cache_tree)
 283                 active_cache_tree = cache_tree();
 284
 285         if (!cache_tree_fully_valid(active_cache_tree))
 286                 if (cache_tree_update(active_cache_tree, active_cache,
 287                                   active_nr, 0))
 288                         return error(_("Unable to update cache tree\n"));
 289
 290         return !hashcmp(active_cache_tree->sha1, head_commit->tree->object.sha1);
 291 }
 292
 293 /*
 294  * If we are cherry-pick, and if the merge did not result in
 295  * hand-editing, we will hit this commit and inherit the original
 296  * author date and name.
 297  * If we are revert, or if our cherry-pick results in a hand merge,
 298  * we had better say that the current user is responsible for that.
 299  */
 300 static int run_git_commit(const char *defmsg, struct replay_opts *opts,
 301                           int allow_empty)
 302 {
 303         struct argv_array array;
 304         int rc;
 305
 306         argv_array_init(&array);
 307         argv_array_push(&array, "commit");
 308         argv_array_push(&array, "-n");
 309
 310         if (opts->signoff)
 311                 argv_array_push(&array, "-s");
 312         if (!opts->edit) {
 313                 argv_array_push(&array, "-F");
 314                 argv_array_push(&array, defmsg);
 315         }
 316
 317         if (allow_empty)
 318                 argv_array_push(&array, "--allow-empty");
 319
 320         if (opts->allow_empty_message)
 321                 argv_array_push(&array, "--allow-empty-message");
 322
 323         rc = run_command_v_opt(array.argv, RUN_GIT_CMD);
 324         argv_array_clear(&array);
 325         return rc;
 326 }
 327
 328 static int is_original_commit_empty(struct commit *commit)
 329 {
 330         const unsigned char *ptree_sha1;
 331
 332         if (parse_commit(commit))
 333                 return error(_("Could not parse commit %s\n"),
 334                              sha1_to_hex(commit->object.sha1));
 335         if (commit->parents) {
 336                 struct commit *parent = commit->parents->item;
 337                 if (parse_commit(parent))
 338                         return error(_("Could not parse parent commit %s\n"),
 339                                 sha1_to_hex(parent->object.sha1));
 340                 ptree_sha1 = parent->tree->object.sha1;
 341         } else {
 342                 ptree_sha1 = EMPTY_TREE_SHA1_BIN; /* commit is root */
 343         }
 344
 345         return !hashcmp(ptree_sha1, commit->tree->object.sha1);
 346 }
 347
 348 /*
 349  * Do we run "git commit" with "--allow-empty"?
 350  */
 351 static int allow_empty(struct replay_opts *opts, struct commit *commit)
 352 {
 353         int index_unchanged, empty_commit;
 354
 355         /*
 356          * Three cases:
 357          *
 358          * (1) we do not allow empty at all and error out.
 359          *
 360          * (2) we allow ones that were initially empty, but
 361          * forbid the ones that become empty;
 362          *
 363          * (3) we allow both.
 364          */
 365         if (!opts->allow_empty)
 366                 return 0; /* let "git commit" barf as necessary */
 367
 368         index_unchanged = is_index_unchanged();
 369         if (index_unchanged < 0)
 370                 return index_unchanged;
 371         if (!index_unchanged)
 372                 return 0; /* we do not have to say --allow-empty */
 373
 374         if (opts->keep_redundant_commits)
 375                 return 1;
 376
 377         empty_commit = is_original_commit_empty(commit);
 378         if (empty_commit < 0)
 379                 return empty_commit;
 380         if (!empty_commit)
 381                 return 0;
 382         else
 383                 return 1;
 384 }
 385
 386 static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
 387 {
 388         unsigned char head[20];
 389         struct commit *base, *next, *parent;
 390         const char *base_label, *next_label;
 391         struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
 392         char *defmsg = NULL;
 393         struct strbuf msgbuf = STRBUF_INIT;
 394         int res, unborn = 0;
 395
 396         if (opts->no_commit) {
 397                 /*
 398                  * We do not intend to commit immediately.  We just want to
 399                  * merge the differences in, so let's compute the tree
 400                  * that represents the "current" state for merge-recursive
 401                  * to work on.
 402                  */
 403                 if (write_cache_as_tree(head, 0, NULL))
 404                         die (_("Your index file is unmerged."));
 405         } else {
 406                 unborn = get_sha1("HEAD", head);
 407                 if (unborn)
 408                         hashcpy(head, EMPTY_TREE_SHA1_BIN);
 409                 if (index_differs_from(unborn ? EMPTY_TREE_SHA1_HEX : "HEAD", 0))
 410                         return error_dirty_index(opts);
 411         }
 412         discard_cache();
 413
 414         if (!commit->parents) {
 415                 parent = NULL;
 416         }
 417         else if (commit->parents->next) {
 418                 /* Reverting or cherry-picking a merge commit */
 419                 int cnt;
 420                 struct commit_list *p;
 421
 422                 if (!opts->mainline)
 423                         return error(_("Commit %s is a merge but no -m option was given."),
 424                                 sha1_to_hex(commit->object.sha1));
 425
 426                 for (cnt = 1, p = commit->parents;
 427                      cnt != opts->mainline && p;
 428                      cnt++)
 429                         p = p->next;
 430                 if (cnt != opts->mainline || !p)
 431                         return error(_("Commit %s does not have parent %d"),
 432                                 sha1_to_hex(commit->object.sha1), opts->mainline);
 433                 parent = p->item;
 434         } else if (0 < opts->mainline)
 435                 return error(_("Mainline was specified but commit %s is not a merge."),
 436                         sha1_to_hex(commit->object.sha1));
 437         else
 438                 parent = commit->parents->item;
 439
 440         if (opts->allow_ff &&
 441             ((parent && !hashcmp(parent->object.sha1, head)) ||
 442              (!parent && unborn)))
 443              return fast_forward_to(commit->object.sha1, head, unborn);
 444
 445         if (parent && parse_commit(parent) < 0)
 446                 /* TRANSLATORS: The first %s will be "revert" or
 447                    "cherry-pick", the second %s a SHA1 */
 448                 return error(_("%s: cannot parse parent commit %s"),
 449                         action_name(opts), sha1_to_hex(parent->object.sha1));
 450
 451         if (get_message(commit, &msg) != 0)
 452                 return error(_("Cannot get commit message for %s"),
 453                         sha1_to_hex(commit->object.sha1));
 454
 455         /*
 456          * "commit" is an existing commit.  We would want to apply
 457          * the difference it introduces since its first parent "prev"
 458          * on top of the current HEAD if we are cherry-pick.  Or the
 459          * reverse of it if we are revert.
 460          */
 461
 462         defmsg = git_pathdup("MERGE_MSG");
 463
 464         if (opts->action == REPLAY_REVERT) {
 465                 base = commit;
 466                 base_label = msg.label;
 467                 next = parent;
 468                 next_label = msg.parent_label;
 469                 strbuf_addstr(&msgbuf, "Revert \"");
 470                 strbuf_addstr(&msgbuf, msg.subject);
 471                 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
 472                 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 473
 474                 if (commit->parents && commit->parents->next) {
 475                         strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
 476                         strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
 477                 }
 478                 strbuf_addstr(&msgbuf, ".\n");
 479         } else {
 480                 const char *p;
 481
 482                 base = parent;
 483                 base_label = msg.parent_label;
 484                 next = commit;
 485                 next_label = msg.label;
 486
 487                 /*
 488                  * Append the commit log message to msgbuf; it starts
 489                  * after the tree, parent, author, committer
 490                  * information followed by "\n\n".
 491                  */
 492                 p = strstr(msg.message, "\n\n");
 493                 if (p) {
 494                         p += 2;
 495                         strbuf_addstr(&msgbuf, p);
 496                 }
 497
 498                 if (opts->record_origin) {
 499                         strbuf_addstr(&msgbuf, "(cherry picked from commit ");
 500                         strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 501                         strbuf_addstr(&msgbuf, ")\n");
 502                 }
 503         }
 504
 505         if (!opts->strategy || !strcmp(opts->strategy, "recursive") || opts->action == REPLAY_REVERT) {
 506                 res = do_recursive_merge(base, next, base_label, next_label,
 507                                          head, &msgbuf, opts);
 508                 write_message(&msgbuf, defmsg);
 509         } else {
 510                 struct commit_list *common = NULL;
 511                 struct commit_list *remotes = NULL;
 512
 513                 write_message(&msgbuf, defmsg);
 514
 515                 commit_list_insert(base, &common);
 516                 commit_list_insert(next, &remotes);
 517                 res = try_merge_command(opts->strategy, opts->xopts_nr, opts->xopts,
 518                                         common, sha1_to_hex(head), remotes);
 519                 free_commit_list(common);
 520                 free_commit_list(remotes);
 521         }
 522
 523         /*
 524          * If the merge was clean or if it failed due to conflict, we write
 525          * CHERRY_PICK_HEAD for the subsequent invocation of commit to use.
 526          * However, if the merge did not even start, then we don't want to
 527          * write it at all.
 528          */
 529         if (opts->action == REPLAY_PICK && !opts->no_commit && (res == 0 || res == 1))
 530                 write_cherry_pick_head(commit, "CHERRY_PICK_HEAD");
 531         if (opts->action == REPLAY_REVERT && ((opts->no_commit && res == 0) || res == 1))
 532                 write_cherry_pick_head(commit, "REVERT_HEAD");
 533
 534         if (res) {
 535                 error(opts->action == REPLAY_REVERT
 536                       ? _("could not revert %s... %s")
 537                       : _("could not apply %s... %s"),
 538                       find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV),
 539                       msg.subject);
 540                 print_advice(res == 1, opts);
 541                 rerere(opts->allow_rerere_auto);
 542         } else {
 543                 int allow = allow_empty(opts, commit);
 544                 if (allow < 0)
 545                         return allow;
 546                 if (!opts->no_commit)
 547                         res = run_git_commit(defmsg, opts, allow);
 548         }
 549
 550         free_message(&msg);
 551         free(defmsg);
 552
 553         return res;
 554 }
 555
 556 static void prepare_revs(struct replay_opts *opts)
 557 {
 558         /*
 559          * picking (but not reverting) ranges (but not individual revisions)
 560          * should be done in reverse
 561          */
 562         if (opts->action == REPLAY_PICK && !opts->revs->no_walk)
 563                 opts->revs->reverse ^= 1;
 564
 565         if (prepare_revision_walk(opts->revs))
 566                 die(_("revision walk setup failed"));
 567
 568         if (!opts->revs->commits)
 569                 die(_("empty commit set passed"));
 570 }
 571
 572 static void read_and_refresh_cache(struct replay_opts *opts)
 573 {
 574         static struct lock_file index_lock;
 575         int index_fd = hold_locked_index(&index_lock, 0);
 576         if (read_index_preload(&the_index, NULL) < 0)
 577                 die(_("git %s: failed to read the index"), action_name(opts));
 578         refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
 579         if (the_index.cache_changed) {
 580                 if (write_index(&the_index, index_fd) ||
 581                     commit_locked_index(&index_lock))
 582                         die(_("git %s: failed to refresh the index"), action_name(opts));
 583         }
 584         rollback_lock_file(&index_lock);
 585 }
 586
 587 static int format_todo(struct strbuf *buf, struct commit_list *todo_list,
 588                 struct replay_opts *opts)
 589 {
 590         struct commit_list *cur = NULL;
 591         const char *sha1_abbrev = NULL;
 592         const char *action_str = opts->action == REPLAY_REVERT ? "revert" : "pick";
 593         const char *subject;
 594         int subject_len;
 595
 596         for (cur = todo_list; cur; cur = cur->next) {
 597                 sha1_abbrev = find_unique_abbrev(cur->item->object.sha1, DEFAULT_ABBREV);
 598                 subject_len = find_commit_subject(cur->item->buffer, &subject);
 599                 strbuf_addf(buf, "%s %s %.*s\n", action_str, sha1_abbrev,
 600                         subject_len, subject);
 601         }
 602         return 0;
 603 }
 604
 605 static struct commit *parse_insn_line(char *bol, char *eol, struct replay_opts *opts)
 606 {
 607         unsigned char commit_sha1[20];
 608         enum replay_action action;
 609         char *end_of_object_name;
 610         int saved, status, padding;
 611
 612         if (!prefixcmp(bol, "pick")) {
 613                 action = REPLAY_PICK;
 614                 bol += strlen("pick");
 615         } else if (!prefixcmp(bol, "revert")) {
 616                 action = REPLAY_REVERT;
 617                 bol += strlen("revert");
 618         } else
 619                 return NULL;
 620
 621         /* Eat up extra spaces/ tabs before object name */
 622         padding = strspn(bol, " \t");
 623         if (!padding)
 624                 return NULL;
 625         bol += padding;
 626
 627         end_of_object_name = bol + strcspn(bol, " \t\n");
 628         saved = *end_of_object_name;
 629         *end_of_object_name = '\0';
 630         status = get_sha1(bol, commit_sha1);
 631         *end_of_object_name = saved;
 632
 633         /*
 634          * Verify that the action matches up with the one in
 635          * opts; we don't support arbitrary instructions
 636          */
 637         if (action != opts->action) {
 638                 const char *action_str;
 639                 action_str = action == REPLAY_REVERT ? "revert" : "cherry-pick";
 640                 error(_("Cannot %s during a %s"), action_str, action_name(opts));
 641                 return NULL;
 642         }
 643
 644         if (status < 0)
 645                 return NULL;
 646
 647         return lookup_commit_reference(commit_sha1);
 648 }
 649
 650 static int parse_insn_buffer(char *buf, struct commit_list **todo_list,
 651                         struct replay_opts *opts)
 652 {
 653         struct commit_list **next = todo_list;
 654         struct commit *commit;
 655         char *p = buf;
 656         int i;
 657
 658         for (i = 1; *p; i++) {
 659                 char *eol = strchrnul(p, '\n');
 660                 commit = parse_insn_line(p, eol, opts);
 661                 if (!commit)
 662                         return error(_("Could not parse line %d."), i);
 663                 next = commit_list_append(commit, next);
 664                 p = *eol ? eol + 1 : eol;
 665         }
 666         if (!*todo_list)
 667                 return error(_("No commits parsed."));
 668         return 0;
 669 }
 670
 671 static void read_populate_todo(struct commit_list **todo_list,
 672                         struct replay_opts *opts)
 673 {
 674         const char *todo_file = git_path(SEQ_TODO_FILE);
 675         struct strbuf buf = STRBUF_INIT;
 676         int fd, res;
 677
 678         fd = open(todo_file, O_RDONLY);
 679         if (fd < 0)
 680                 die_errno(_("Could not open %s"), todo_file);
 681         if (strbuf_read(&buf, fd, 0) < 0) {
 682                 close(fd);
 683                 strbuf_release(&buf);
 684                 die(_("Could not read %s."), todo_file);
 685         }
 686         close(fd);
 687
 688         res = parse_insn_buffer(buf.buf, todo_list, opts);
 689         strbuf_release(&buf);
 690         if (res)
 691                 die(_("Unusable instruction sheet: %s"), todo_file);
 692 }
 693
 694 static int populate_opts_cb(const char *key, const char *value, void *data)
 695 {
 696         struct replay_opts *opts = data;
 697         int error_flag = 1;
 698
 699         if (!value)
 700                 error_flag = 0;
 701         else if (!strcmp(key, "options.no-commit"))
 702                 opts->no_commit = git_config_bool_or_int(key, value, &error_flag);
 703         else if (!strcmp(key, "options.edit"))
 704                 opts->edit = git_config_bool_or_int(key, value, &error_flag);
 705         else if (!strcmp(key, "options.signoff"))
 706                 opts->signoff = git_config_bool_or_int(key, value, &error_flag);
 707         else if (!strcmp(key, "options.record-origin"))
 708                 opts->record_origin = git_config_bool_or_int(key, value, &error_flag);
 709         else if (!strcmp(key, "options.allow-ff"))
 710                 opts->allow_ff = git_config_bool_or_int(key, value, &error_flag);
 711         else if (!strcmp(key, "options.mainline"))
 712                 opts->mainline = git_config_int(key, value);
 713         else if (!strcmp(key, "options.strategy"))
 714                 git_config_string(&opts->strategy, key, value);
 715         else if (!strcmp(key, "options.strategy-option")) {
 716                 ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
 717                 opts->xopts[opts->xopts_nr++] = xstrdup(value);
 718         } else
 719                 return error(_("Invalid key: %s"), key);
 720
 721         if (!error_flag)
 722                 return error(_("Invalid value for %s: %s"), key, value);
 723
 724         return 0;
 725 }
 726
 727 static void read_populate_opts(struct replay_opts **opts_ptr)
 728 {
 729         const char *opts_file = git_path(SEQ_OPTS_FILE);
 730
 731         if (!file_exists(opts_file))
 732                 return;
 733         if (git_config_from_file(populate_opts_cb, opts_file, *opts_ptr) < 0)
 734                 die(_("Malformed options sheet: %s"), opts_file);
 735 }
 736
 737 static void walk_revs_populate_todo(struct commit_list **todo_list,
 738                                 struct replay_opts *opts)
 739 {
 740         struct commit *commit;
 741         struct commit_list **next;
 742
 743         prepare_revs(opts);
 744
 745         next = todo_list;
 746         while ((commit = get_revision(opts->revs)))
 747                 next = commit_list_append(commit, next);
 748 }
 749
 750 static int create_seq_dir(void)
 751 {
 752         const char *seq_dir = git_path(SEQ_DIR);
 753
 754         if (file_exists(seq_dir)) {
 755                 error(_("a cherry-pick or revert is already in progress"));
 756                 advise(_("try \"git cherry-pick (--continue | --quit | --abort)\""));
 757                 return -1;
 758         }
 759         else if (mkdir(seq_dir, 0777) < 0)
 760                 die_errno(_("Could not create sequencer directory %s"), seq_dir);
 761         return 0;
 762 }
 763
 764 static void save_head(const char *head)
 765 {
 766         const char *head_file = git_path(SEQ_HEAD_FILE);
 767         static struct lock_file head_lock;
 768         struct strbuf buf = STRBUF_INIT;
 769         int fd;
 770
 771         fd = hold_lock_file_for_update(&head_lock, head_file, LOCK_DIE_ON_ERROR);
 772         strbuf_addf(&buf, "%s\n", head);
 773         if (write_in_full(fd, buf.buf, buf.len) < 0)
 774                 die_errno(_("Could not write to %s"), head_file);
 775         if (commit_lock_file(&head_lock) < 0)
 776                 die(_("Error wrapping up %s."), head_file);
 777 }
 778
 779 static int reset_for_rollback(const unsigned char *sha1)
 780 {
 781         const char *argv[4];    /* reset --merge <arg> + NULL */
 782         argv[0] = "reset";
 783         argv[1] = "--merge";
 784         argv[2] = sha1_to_hex(sha1);
 785         argv[3] = NULL;
 786         return run_command_v_opt(argv, RUN_GIT_CMD);
 787 }
 788
 789 static int rollback_single_pick(void)
 790 {
 791         unsigned char head_sha1[20];
 792
 793         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
 794             !file_exists(git_path("REVERT_HEAD")))
 795                 return error(_("no cherry-pick or revert in progress"));
 796         if (read_ref_full("HEAD", head_sha1, 0, NULL))
 797                 return error(_("cannot resolve HEAD"));
 798         if (is_null_sha1(head_sha1))
 799                 return error(_("cannot abort from a branch yet to be born"));
 800         return reset_for_rollback(head_sha1);
 801 }
 802
 803 static int sequencer_rollback(struct replay_opts *opts)
 804 {
 805         const char *filename;
 806         FILE *f;
 807         unsigned char sha1[20];
 808         struct strbuf buf = STRBUF_INIT;
 809
 810         filename = git_path(SEQ_HEAD_FILE);
 811         f = fopen(filename, "r");
 812         if (!f && errno == ENOENT) {
 813                 /*
 814                  * There is no multiple-cherry-pick in progress.
 815                  * If CHERRY_PICK_HEAD or REVERT_HEAD indicates
 816                  * a single-cherry-pick in progress, abort that.
 817                  */
 818                 return rollback_single_pick();
 819         }
 820         if (!f)
 821                 return error(_("cannot open %s: %s"), filename,
 822                                                 strerror(errno));
 823         if (strbuf_getline(&buf, f, '\n')) {
 824                 error(_("cannot read %s: %s"), filename, ferror(f) ?
 825                         strerror(errno) : _("unexpected end of file"));
 826                 fclose(f);
 827                 goto fail;
 828         }
 829         fclose(f);
 830         if (get_sha1_hex(buf.buf, sha1) || buf.buf[40] != '\0') {
 831                 error(_("stored pre-cherry-pick HEAD file '%s' is corrupt"),
 832                         filename);
 833                 goto fail;
 834         }
 835         if (reset_for_rollback(sha1))
 836                 goto fail;
 837         remove_sequencer_state();
 838         strbuf_release(&buf);
 839         return 0;
 840 fail:
 841         strbuf_release(&buf);
 842         return -1;
 843 }
 844
 845 static void save_todo(struct commit_list *todo_list, struct replay_opts *opts)
 846 {
 847         const char *todo_file = git_path(SEQ_TODO_FILE);
 848         static struct lock_file todo_lock;
 849         struct strbuf buf = STRBUF_INIT;
 850         int fd;
 851
 852         fd = hold_lock_file_for_update(&todo_lock, todo_file, LOCK_DIE_ON_ERROR);
 853         if (format_todo(&buf, todo_list, opts) < 0)
 854                 die(_("Could not format %s."), todo_file);
 855         if (write_in_full(fd, buf.buf, buf.len) < 0) {
 856                 strbuf_release(&buf);
 857                 die_errno(_("Could not write to %s"), todo_file);
 858         }
 859         if (commit_lock_file(&todo_lock) < 0) {
 860                 strbuf_release(&buf);
 861                 die(_("Error wrapping up %s."), todo_file);
 862         }
 863         strbuf_release(&buf);
 864 }
 865
 866 static void save_opts(struct replay_opts *opts)
 867 {
 868         const char *opts_file = git_path(SEQ_OPTS_FILE);
 869
 870         if (opts->no_commit)
 871                 git_config_set_in_file(opts_file, "options.no-commit", "true");
 872         if (opts->edit)
 873                 git_config_set_in_file(opts_file, "options.edit", "true");
 874         if (opts->signoff)
 875                 git_config_set_in_file(opts_file, "options.signoff", "true");
 876         if (opts->record_origin)
 877                 git_config_set_in_file(opts_file, "options.record-origin", "true");
 878         if (opts->allow_ff)
 879                 git_config_set_in_file(opts_file, "options.allow-ff", "true");
 880         if (opts->mainline) {
 881                 struct strbuf buf = STRBUF_INIT;
 882                 strbuf_addf(&buf, "%d", opts->mainline);
 883                 git_config_set_in_file(opts_file, "options.mainline", buf.buf);
 884                 strbuf_release(&buf);
 885         }
 886         if (opts->strategy)
 887                 git_config_set_in_file(opts_file, "options.strategy", opts->strategy);
 888         if (opts->xopts) {
 889                 int i;
 890                 for (i = 0; i < opts->xopts_nr; i++)
 891                         git_config_set_multivar_in_file(opts_file,
 892                                                         "options.strategy-option",
 893                                                         opts->xopts[i], "^$", 0);
 894         }
 895 }
 896
 897 static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
 898 {
 899         struct commit_list *cur;
 900         int res;
 901
 902         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
 903         if (opts->allow_ff)
 904                 assert(!(opts->signoff || opts->no_commit ||
 905                                 opts->record_origin || opts->edit));
 906         read_and_refresh_cache(opts);
 907
 908         for (cur = todo_list; cur; cur = cur->next) {
 909                 save_todo(cur, opts);
 910                 res = do_pick_commit(cur->item, opts);
 911                 if (res)
 912                         return res;
 913         }
 914
 915         /*
 916          * Sequence of picks finished successfully; cleanup by
 917          * removing the .git/sequencer directory
 918          */
 919         remove_sequencer_state();
 920         return 0;
 921 }
 922
 923 static int continue_single_pick(void)
 924 {
 925         const char *argv[] = { "commit", NULL };
 926
 927         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
 928             !file_exists(git_path("REVERT_HEAD")))
 929                 return error(_("no cherry-pick or revert in progress"));
 930         return run_command_v_opt(argv, RUN_GIT_CMD);
 931 }
 932
 933 static int sequencer_continue(struct replay_opts *opts)
 934 {
 935         struct commit_list *todo_list = NULL;
 936
 937         if (!file_exists(git_path(SEQ_TODO_FILE)))
 938                 return continue_single_pick();
 939         read_populate_opts(&opts);
 940         read_populate_todo(&todo_list, opts);
 941
 942         /* Verify that the conflict has been resolved */
 943         if (file_exists(git_path("CHERRY_PICK_HEAD")) ||
 944             file_exists(git_path("REVERT_HEAD"))) {
 945                 int ret = continue_single_pick();
 946                 if (ret)
 947                         return ret;
 948         }
 949         if (index_differs_from("HEAD", 0))
 950                 return error_dirty_index(opts);
 951         todo_list = todo_list->next;
 952         return pick_commits(todo_list, opts);
 953 }
 954
 955 static int single_pick(struct commit *cmit, struct replay_opts *opts)
 956 {
 957         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
 958         return do_pick_commit(cmit, opts);
 959 }
 960
 961 int sequencer_pick_revisions(struct replay_opts *opts)
 962 {
 963         struct commit_list *todo_list = NULL;
 964         unsigned char sha1[20];
 965
 966         if (opts->subcommand == REPLAY_NONE)
 967                 assert(opts->revs);
 968
 969         read_and_refresh_cache(opts);
 970
 971         /*
 972          * Decide what to do depending on the arguments; a fresh
 973          * cherry-pick should be handled differently from an existing
 974          * one that is being continued
 975          */
 976         if (opts->subcommand == REPLAY_REMOVE_STATE) {
 977                 remove_sequencer_state();
 978                 return 0;
 979         }
 980         if (opts->subcommand == REPLAY_ROLLBACK)
 981                 return sequencer_rollback(opts);
 982         if (opts->subcommand == REPLAY_CONTINUE)
 983                 return sequencer_continue(opts);
 984
 985         /*
 986          * If we were called as "git cherry-pick <commit>", just
 987          * cherry-pick/revert it, set CHERRY_PICK_HEAD /
 988          * REVERT_HEAD, and don't touch the sequencer state.
 989          * This means it is possible to cherry-pick in the middle
 990          * of a cherry-pick sequence.
 991          */
 992         if (opts->revs->cmdline.nr == 1 &&
 993             opts->revs->cmdline.rev->whence == REV_CMD_REV &&
 994             opts->revs->no_walk &&
 995             !opts->revs->cmdline.rev->flags) {
 996                 struct commit *cmit;
 997                 if (prepare_revision_walk(opts->revs))
 998                         die(_("revision walk setup failed"));
 999                 cmit = get_revision(opts->revs);
1000                 if (!cmit || get_revision(opts->revs))
1001                         die("BUG: expected exactly one commit from walk");
1002                 return single_pick(cmit, opts);
1003         }
1004
1005         /*
1006          * Start a new cherry-pick/ revert sequence; but
1007          * first, make sure that an existing one isn't in
1008          * progress
1009          */
1010
1011         walk_revs_populate_todo(&todo_list, opts);
1012         if (create_seq_dir() < 0)
1013                 return -1;
1014         if (get_sha1("HEAD", sha1)) {
1015                 if (opts->action == REPLAY_REVERT)
1016                         return error(_("Can't revert as initial commit"));
1017                 return error(_("Can't cherry-pick into empty head"));
1018         }
1019         save_head(sha1_to_hex(sha1));
1020         save_opts(opts);
1021         return pick_commits(todo_list, opts);
1022 }
1023
1024 static int ends_rfc2822_footer(struct strbuf *sb, int ignore_footer)
1025 {
1026         int ch;
1027         int hit = 0;
1028         int i, j, k;
1029         int len = sb->len - ignore_footer;
1030         int first = 1;
1031         const char *buf = sb->buf;
1032
1033         for (i = len - 1; i > 0; i--) {
1034                 if (hit && buf[i] == '\n')
1035                         break;
1036                 hit = (buf[i] == '\n');
1037         }
1038
1039         while (i < len - 1 && buf[i] == '\n')
1040                 i++;
1041
1042         for (; i < len; i = k) {
1043                 for (k = i; k < len && buf[k] != '\n'; k++)
1044                         ; /* do nothing */
1045                 k++;
1046
1047                 if ((buf[k] == ' ' || buf[k] == '\t') && !first)
1048                         continue;
1049
1050                 first = 0;
1051
1052                 for (j = 0; i + j < len; j++) {
1053                         ch = buf[i + j];
1054                         if (ch == ':')
1055                                 break;
1056                         if (isalnum(ch) ||
1057                             (ch == '-'))
1058                                 continue;
1059                         return 0;
1060                 }
1061         }
1062         return 1;
1063 }
1064
1065 void append_signoff(struct strbuf *msgbuf, int ignore_footer)
1066 {
1067         struct strbuf sob = STRBUF_INIT;
1068         int i;
1069
1070         strbuf_addstr(&sob, sign_off_header);
1071         strbuf_addstr(&sob, fmt_name(getenv("GIT_COMMITTER_NAME"),
1072                                 getenv("GIT_COMMITTER_EMAIL")));
1073         strbuf_addch(&sob, '\n');
1074         for (i = msgbuf->len - 1 - ignore_footer; i > 0 && msgbuf->buf[i - 1] != '\n'; i--)
1075                 ; /* do nothing */
1076         if (prefixcmp(msgbuf->buf + i, sob.buf)) {
1077                 if (!i || !ends_rfc2822_footer(msgbuf, ignore_footer))
1078                         strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0, "\n", 1);
1079                 strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0, sob.buf, sob.len);
1080         }
1081         strbuf_release(&sob);
1082 }