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 /*
  48  * Returns 0 for non-conforming footer
  49  * Returns 1 for conforming footer
  50  * Returns 2 when sob exists within conforming footer
  51  * Returns 3 when sob exists within conforming footer as last entry
  52  */
  53 static int has_conforming_footer(struct strbuf *sb, struct strbuf *sob,
  54         int ignore_footer)
  55 {
  56         char prev;
  57         int i, k;
  58         int len = sb->len - ignore_footer;
  59         const char *buf = sb->buf;
  60         int found_sob = 0;
  61
  62         /* footer must end with newline */
  63         if (!len || buf[len - 1] != '\n')
  64                 return 0;
  65
  66         prev = '\0';
  67         for (i = len - 1; i > 0; i--) {
  68                 char ch = buf[i];
  69                 if (prev == '\n' && ch == '\n') /* paragraph break */
  70                         break;
  71                 prev = ch;
  72         }
  73
  74         /* require at least one blank line */
  75         if (prev != '\n' || buf[i] != '\n')
  76                 return 0;
  77
  78         /* advance to start of last paragraph */
  79         while (i < len - 1 && buf[i] == '\n')
  80                 i++;
  81
  82         for (; i < len; i = k) {
  83                 int found_rfc2822;
  84
  85                 for (k = i; k < len && buf[k] != '\n'; k++)
  86                         ; /* do nothing */
  87                 k++;
  88
  89                 found_rfc2822 = is_rfc2822_line(buf + i, k - i - 1);
  90                 if (found_rfc2822 && sob &&
  91                     !strncmp(buf + i, sob->buf, sob->len))
  92                         found_sob = k;
  93
  94                 if (!(found_rfc2822 ||
  95                       is_cherry_picked_from_line(buf + i, k - i - 1)))
  96                         return 0;
  97         }
  98         if (found_sob == i)
  99                 return 3;
 100         if (found_sob)
 101                 return 2;
 102         return 1;
 103 }
 104
 105 static void remove_sequencer_state(void)
 106 {
 107         struct strbuf seq_dir = STRBUF_INIT;
 108
 109         strbuf_addf(&seq_dir, "%s", git_path(SEQ_DIR));
 110         remove_dir_recursively(&seq_dir, 0);
 111         strbuf_release(&seq_dir);
 112 }
 113
 114 static const char *action_name(const struct replay_opts *opts)
 115 {
 116         return opts->action == REPLAY_REVERT ? "revert" : "cherry-pick";
 117 }
 118
 119 static char *get_encoding(const char *message);
 120
 121 struct commit_message {
 122         char *parent_label;
 123         const char *label;
 124         const char *subject;
 125         char *reencoded_message;
 126         const char *message;
 127 };
 128
 129 static int get_message(struct commit *commit, struct commit_message *out)
 130 {
 131         const char *encoding;
 132         const char *abbrev, *subject;
 133         int abbrev_len, subject_len;
 134         char *q;
 135
 136         if (!commit->buffer)
 137                 return -1;
 138         encoding = get_encoding(commit->buffer);
 139         if (!encoding)
 140                 encoding = "UTF-8";
 141         if (!git_commit_encoding)
 142                 git_commit_encoding = "UTF-8";
 143
 144         out->reencoded_message = NULL;
 145         out->message = commit->buffer;
 146         if (same_encoding(encoding, git_commit_encoding))
 147                 out->reencoded_message = reencode_string(commit->buffer,
 148                                         git_commit_encoding, encoding);
 149         if (out->reencoded_message)
 150                 out->message = out->reencoded_message;
 151
 152         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
 153         abbrev_len = strlen(abbrev);
 154
 155         subject_len = find_commit_subject(out->message, &subject);
 156
 157         out->parent_label = xmalloc(strlen("parent of ") + abbrev_len +
 158                               strlen("... ") + subject_len + 1);
 159         q = out->parent_label;
 160         q = mempcpy(q, "parent of ", strlen("parent of "));
 161         out->label = q;
 162         q = mempcpy(q, abbrev, abbrev_len);
 163         q = mempcpy(q, "... ", strlen("... "));
 164         out->subject = q;
 165         q = mempcpy(q, subject, subject_len);
 166         *q = '\0';
 167         return 0;
 168 }
 169
 170 static void free_message(struct commit_message *msg)
 171 {
 172         free(msg->parent_label);
 173         free(msg->reencoded_message);
 174 }
 175
 176 static char *get_encoding(const char *message)
 177 {
 178         const char *p = message, *eol;
 179
 180         while (*p && *p != '\n') {
 181                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
 182                         ; /* do nothing */
 183                 if (!prefixcmp(p, "encoding ")) {
 184                         char *result = xmalloc(eol - 8 - p);
 185                         strlcpy(result, p + 9, eol - 8 - p);
 186                         return result;
 187                 }
 188                 p = eol;
 189                 if (*p == '\n')
 190                         p++;
 191         }
 192         return NULL;
 193 }
 194
 195 static void write_cherry_pick_head(struct commit *commit, const char *pseudoref)
 196 {
 197         const char *filename;
 198         int fd;
 199         struct strbuf buf = STRBUF_INIT;
 200
 201         strbuf_addf(&buf, "%s\n", sha1_to_hex(commit->object.sha1));
 202
 203         filename = git_path("%s", pseudoref);
 204         fd = open(filename, O_WRONLY | O_CREAT, 0666);
 205         if (fd < 0)
 206                 die_errno(_("Could not open '%s' for writing"), filename);
 207         if (write_in_full(fd, buf.buf, buf.len) != buf.len || close(fd))
 208                 die_errno(_("Could not write to '%s'"), filename);
 209         strbuf_release(&buf);
 210 }
 211
 212 static void print_advice(int show_hint, struct replay_opts *opts)
 213 {
 214         char *msg = getenv("GIT_CHERRY_PICK_HELP");
 215
 216         if (msg) {
 217                 fprintf(stderr, "%s\n", msg);
 218                 /*
 219                  * A conflict has occurred but the porcelain
 220                  * (typically rebase --interactive) wants to take care
 221                  * of the commit itself so remove CHERRY_PICK_HEAD
 222                  */
 223                 unlink(git_path("CHERRY_PICK_HEAD"));
 224                 return;
 225         }
 226
 227         if (show_hint) {
 228                 if (opts->no_commit)
 229                         advise(_("after resolving the conflicts, mark the corrected paths\n"
 230                                  "with 'git add <paths>' or 'git rm <paths>'"));
 231                 else
 232                         advise(_("after resolving the conflicts, mark the corrected paths\n"
 233                                  "with 'git add <paths>' or 'git rm <paths>'\n"
 234                                  "and commit the result with 'git commit'"));
 235         }
 236 }
 237
 238 static void write_message(struct strbuf *msgbuf, const char *filename)
 239 {
 240         static struct lock_file msg_file;
 241
 242         int msg_fd = hold_lock_file_for_update(&msg_file, filename,
 243                                                LOCK_DIE_ON_ERROR);
 244         if (write_in_full(msg_fd, msgbuf->buf, msgbuf->len) < 0)
 245                 die_errno(_("Could not write to %s"), filename);
 246         strbuf_release(msgbuf);
 247         if (commit_lock_file(&msg_file) < 0)
 248                 die(_("Error wrapping up %s"), filename);
 249 }
 250
 251 static struct tree *empty_tree(void)
 252 {
 253         return lookup_tree(EMPTY_TREE_SHA1_BIN);
 254 }
 255
 256 static int error_dirty_index(struct replay_opts *opts)
 257 {
 258         if (read_cache_unmerged())
 259                 return error_resolve_conflict(action_name(opts));
 260
 261         /* Different translation strings for cherry-pick and revert */
 262         if (opts->action == REPLAY_PICK)
 263                 error(_("Your local changes would be overwritten by cherry-pick."));
 264         else
 265                 error(_("Your local changes would be overwritten by revert."));
 266
 267         if (advice_commit_before_merge)
 268                 advise(_("Commit your changes or stash them to proceed."));
 269         return -1;
 270 }
 271
 272 static int fast_forward_to(const unsigned char *to, const unsigned char *from,
 273                            int unborn)
 274 {
 275         struct ref_lock *ref_lock;
 276
 277         read_cache();
 278         if (checkout_fast_forward(from, to, 1))
 279                 exit(1); /* the callee should have complained already */
 280         ref_lock = lock_any_ref_for_update("HEAD", unborn ? null_sha1 : from, 0);
 281         return write_ref_sha1(ref_lock, to, "cherry-pick");
 282 }
 283
 284 static int do_recursive_merge(struct commit *base, struct commit *next,
 285                               const char *base_label, const char *next_label,
 286                               unsigned char *head, struct strbuf *msgbuf,
 287                               struct replay_opts *opts)
 288 {
 289         struct merge_options o;
 290         struct tree *result, *next_tree, *base_tree, *head_tree;
 291         int clean, index_fd;
 292         const char **xopt;
 293         static struct lock_file index_lock;
 294
 295         index_fd = hold_locked_index(&index_lock, 1);
 296
 297         read_cache();
 298
 299         init_merge_options(&o);
 300         o.ancestor = base ? base_label : "(empty tree)";
 301         o.branch1 = "HEAD";
 302         o.branch2 = next ? next_label : "(empty tree)";
 303
 304         head_tree = parse_tree_indirect(head);
 305         next_tree = next ? next->tree : empty_tree();
 306         base_tree = base ? base->tree : empty_tree();
 307
 308         for (xopt = opts->xopts; xopt != opts->xopts + opts->xopts_nr; xopt++)
 309                 parse_merge_opt(&o, *xopt);
 310
 311         clean = merge_trees(&o,
 312                             head_tree,
 313                             next_tree, base_tree, &result);
 314
 315         if (active_cache_changed &&
 316             (write_cache(index_fd, active_cache, active_nr) ||
 317              commit_locked_index(&index_lock)))
 318                 /* TRANSLATORS: %s will be "revert" or "cherry-pick" */
 319                 die(_("%s: Unable to write new index file"), action_name(opts));
 320         rollback_lock_file(&index_lock);
 321
 322         if (opts->signoff)
 323                 append_signoff(msgbuf, 0, 0);
 324
 325         if (!clean) {
 326                 int i;
 327                 strbuf_addstr(msgbuf, "\nConflicts:\n");
 328                 for (i = 0; i < active_nr;) {
 329                         struct cache_entry *ce = active_cache[i++];
 330                         if (ce_stage(ce)) {
 331                                 strbuf_addch(msgbuf, '\t');
 332                                 strbuf_addstr(msgbuf, ce->name);
 333                                 strbuf_addch(msgbuf, '\n');
 334                                 while (i < active_nr && !strcmp(ce->name,
 335                                                 active_cache[i]->name))
 336                                         i++;
 337                         }
 338                 }
 339         }
 340
 341         return !clean;
 342 }
 343
 344 static int is_index_unchanged(void)
 345 {
 346         unsigned char head_sha1[20];
 347         struct commit *head_commit;
 348
 349         if (!resolve_ref_unsafe("HEAD", head_sha1, 1, NULL))
 350                 return error(_("Could not resolve HEAD commit\n"));
 351
 352         head_commit = lookup_commit(head_sha1);
 353
 354         /*
 355          * If head_commit is NULL, check_commit, called from
 356          * lookup_commit, would have indicated that head_commit is not
 357          * a commit object already.  parse_commit() will return failure
 358          * without further complaints in such a case.  Otherwise, if
 359          * the commit is invalid, parse_commit() will complain.  So
 360          * there is nothing for us to say here.  Just return failure.
 361          */
 362         if (parse_commit(head_commit))
 363                 return -1;
 364
 365         if (!active_cache_tree)
 366                 active_cache_tree = cache_tree();
 367
 368         if (!cache_tree_fully_valid(active_cache_tree))
 369                 if (cache_tree_update(active_cache_tree, active_cache,
 370                                   active_nr, 0))
 371                         return error(_("Unable to update cache tree\n"));
 372
 373         return !hashcmp(active_cache_tree->sha1, head_commit->tree->object.sha1);
 374 }
 375
 376 /*
 377  * If we are cherry-pick, and if the merge did not result in
 378  * hand-editing, we will hit this commit and inherit the original
 379  * author date and name.
 380  * If we are revert, or if our cherry-pick results in a hand merge,
 381  * we had better say that the current user is responsible for that.
 382  */
 383 static int run_git_commit(const char *defmsg, struct replay_opts *opts,
 384                           int allow_empty)
 385 {
 386         struct argv_array array;
 387         int rc;
 388
 389         argv_array_init(&array);
 390         argv_array_push(&array, "commit");
 391         argv_array_push(&array, "-n");
 392
 393         if (opts->signoff)
 394                 argv_array_push(&array, "-s");
 395         if (!opts->edit) {
 396                 argv_array_push(&array, "-F");
 397                 argv_array_push(&array, defmsg);
 398         }
 399
 400         if (allow_empty)
 401                 argv_array_push(&array, "--allow-empty");
 402
 403         if (opts->allow_empty_message)
 404                 argv_array_push(&array, "--allow-empty-message");
 405
 406         rc = run_command_v_opt(array.argv, RUN_GIT_CMD);
 407         argv_array_clear(&array);
 408         return rc;
 409 }
 410
 411 static int is_original_commit_empty(struct commit *commit)
 412 {
 413         const unsigned char *ptree_sha1;
 414
 415         if (parse_commit(commit))
 416                 return error(_("Could not parse commit %s\n"),
 417                              sha1_to_hex(commit->object.sha1));
 418         if (commit->parents) {
 419                 struct commit *parent = commit->parents->item;
 420                 if (parse_commit(parent))
 421                         return error(_("Could not parse parent commit %s\n"),
 422                                 sha1_to_hex(parent->object.sha1));
 423                 ptree_sha1 = parent->tree->object.sha1;
 424         } else {
 425                 ptree_sha1 = EMPTY_TREE_SHA1_BIN; /* commit is root */
 426         }
 427
 428         return !hashcmp(ptree_sha1, commit->tree->object.sha1);
 429 }
 430
 431 /*
 432  * Do we run "git commit" with "--allow-empty"?
 433  */
 434 static int allow_empty(struct replay_opts *opts, struct commit *commit)
 435 {
 436         int index_unchanged, empty_commit;
 437
 438         /*
 439          * Three cases:
 440          *
 441          * (1) we do not allow empty at all and error out.
 442          *
 443          * (2) we allow ones that were initially empty, but
 444          * forbid the ones that become empty;
 445          *
 446          * (3) we allow both.
 447          */
 448         if (!opts->allow_empty)
 449                 return 0; /* let "git commit" barf as necessary */
 450
 451         index_unchanged = is_index_unchanged();
 452         if (index_unchanged < 0)
 453                 return index_unchanged;
 454         if (!index_unchanged)
 455                 return 0; /* we do not have to say --allow-empty */
 456
 457         if (opts->keep_redundant_commits)
 458                 return 1;
 459
 460         empty_commit = is_original_commit_empty(commit);
 461         if (empty_commit < 0)
 462                 return empty_commit;
 463         if (!empty_commit)
 464                 return 0;
 465         else
 466                 return 1;
 467 }
 468
 469 static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
 470 {
 471         unsigned char head[20];
 472         struct commit *base, *next, *parent;
 473         const char *base_label, *next_label;
 474         struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
 475         char *defmsg = NULL;
 476         struct strbuf msgbuf = STRBUF_INIT;
 477         int res, unborn = 0;
 478
 479         if (opts->no_commit) {
 480                 /*
 481                  * We do not intend to commit immediately.  We just want to
 482                  * merge the differences in, so let's compute the tree
 483                  * that represents the "current" state for merge-recursive
 484                  * to work on.
 485                  */
 486                 if (write_cache_as_tree(head, 0, NULL))
 487                         die (_("Your index file is unmerged."));
 488         } else {
 489                 unborn = get_sha1("HEAD", head);
 490                 if (unborn)
 491                         hashcpy(head, EMPTY_TREE_SHA1_BIN);
 492                 if (index_differs_from(unborn ? EMPTY_TREE_SHA1_HEX : "HEAD", 0))
 493                         return error_dirty_index(opts);
 494         }
 495         discard_cache();
 496
 497         if (!commit->parents) {
 498                 parent = NULL;
 499         }
 500         else if (commit->parents->next) {
 501                 /* Reverting or cherry-picking a merge commit */
 502                 int cnt;
 503                 struct commit_list *p;
 504
 505                 if (!opts->mainline)
 506                         return error(_("Commit %s is a merge but no -m option was given."),
 507                                 sha1_to_hex(commit->object.sha1));
 508
 509                 for (cnt = 1, p = commit->parents;
 510                      cnt != opts->mainline && p;
 511                      cnt++)
 512                         p = p->next;
 513                 if (cnt != opts->mainline || !p)
 514                         return error(_("Commit %s does not have parent %d"),
 515                                 sha1_to_hex(commit->object.sha1), opts->mainline);
 516                 parent = p->item;
 517         } else if (0 < opts->mainline)
 518                 return error(_("Mainline was specified but commit %s is not a merge."),
 519                         sha1_to_hex(commit->object.sha1));
 520         else
 521                 parent = commit->parents->item;
 522
 523         if (opts->allow_ff &&
 524             ((parent && !hashcmp(parent->object.sha1, head)) ||
 525              (!parent && unborn)))
 526              return fast_forward_to(commit->object.sha1, head, unborn);
 527
 528         if (parent && parse_commit(parent) < 0)
 529                 /* TRANSLATORS: The first %s will be "revert" or
 530                    "cherry-pick", the second %s a SHA1 */
 531                 return error(_("%s: cannot parse parent commit %s"),
 532                         action_name(opts), sha1_to_hex(parent->object.sha1));
 533
 534         if (get_message(commit, &msg) != 0)
 535                 return error(_("Cannot get commit message for %s"),
 536                         sha1_to_hex(commit->object.sha1));
 537
 538         /*
 539          * "commit" is an existing commit.  We would want to apply
 540          * the difference it introduces since its first parent "prev"
 541          * on top of the current HEAD if we are cherry-pick.  Or the
 542          * reverse of it if we are revert.
 543          */
 544
 545         defmsg = git_pathdup("MERGE_MSG");
 546
 547         if (opts->action == REPLAY_REVERT) {
 548                 base = commit;
 549                 base_label = msg.label;
 550                 next = parent;
 551                 next_label = msg.parent_label;
 552                 strbuf_addstr(&msgbuf, "Revert \"");
 553                 strbuf_addstr(&msgbuf, msg.subject);
 554                 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
 555                 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 556
 557                 if (commit->parents && commit->parents->next) {
 558                         strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
 559                         strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
 560                 }
 561                 strbuf_addstr(&msgbuf, ".\n");
 562         } else {
 563                 const char *p;
 564
 565                 base = parent;
 566                 base_label = msg.parent_label;
 567                 next = commit;
 568                 next_label = msg.label;
 569
 570                 /*
 571                  * Append the commit log message to msgbuf; it starts
 572                  * after the tree, parent, author, committer
 573                  * information followed by "\n\n".
 574                  */
 575                 p = strstr(msg.message, "\n\n");
 576                 if (p) {
 577                         p += 2;
 578                         strbuf_addstr(&msgbuf, p);
 579                 }
 580
 581                 if (opts->record_origin) {
 582                         if (!has_conforming_footer(&msgbuf, NULL, 0))
 583                                 strbuf_addch(&msgbuf, '\n');
 584                         strbuf_addstr(&msgbuf, cherry_picked_prefix);
 585                         strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 586                         strbuf_addstr(&msgbuf, ")\n");
 587                 }
 588         }
 589
 590         if (!opts->strategy || !strcmp(opts->strategy, "recursive") || opts->action == REPLAY_REVERT) {
 591                 res = do_recursive_merge(base, next, base_label, next_label,
 592                                          head, &msgbuf, opts);
 593                 write_message(&msgbuf, defmsg);
 594         } else {
 595                 struct commit_list *common = NULL;
 596                 struct commit_list *remotes = NULL;
 597
 598                 write_message(&msgbuf, defmsg);
 599
 600                 commit_list_insert(base, &common);
 601                 commit_list_insert(next, &remotes);
 602                 res = try_merge_command(opts->strategy, opts->xopts_nr, opts->xopts,
 603                                         common, sha1_to_hex(head), remotes);
 604                 free_commit_list(common);
 605                 free_commit_list(remotes);
 606         }
 607
 608         /*
 609          * If the merge was clean or if it failed due to conflict, we write
 610          * CHERRY_PICK_HEAD for the subsequent invocation of commit to use.
 611          * However, if the merge did not even start, then we don't want to
 612          * write it at all.
 613          */
 614         if (opts->action == REPLAY_PICK && !opts->no_commit && (res == 0 || res == 1))
 615                 write_cherry_pick_head(commit, "CHERRY_PICK_HEAD");
 616         if (opts->action == REPLAY_REVERT && ((opts->no_commit && res == 0) || res == 1))
 617                 write_cherry_pick_head(commit, "REVERT_HEAD");
 618
 619         if (res) {
 620                 error(opts->action == REPLAY_REVERT
 621                       ? _("could not revert %s... %s")
 622                       : _("could not apply %s... %s"),
 623                       find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV),
 624                       msg.subject);
 625                 print_advice(res == 1, opts);
 626                 rerere(opts->allow_rerere_auto);
 627         } else {
 628                 int allow = allow_empty(opts, commit);
 629                 if (allow < 0)
 630                         return allow;
 631                 if (!opts->no_commit)
 632                         res = run_git_commit(defmsg, opts, allow);
 633         }
 634
 635         free_message(&msg);
 636         free(defmsg);
 637
 638         return res;
 639 }
 640
 641 static void prepare_revs(struct replay_opts *opts)
 642 {
 643         /*
 644          * picking (but not reverting) ranges (but not individual revisions)
 645          * should be done in reverse
 646          */
 647         if (opts->action == REPLAY_PICK && !opts->revs->no_walk)
 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 static int format_todo(struct strbuf *buf, struct commit_list *todo_list,
 673                 struct replay_opts *opts)
 674 {
 675         struct commit_list *cur = NULL;
 676         const char *sha1_abbrev = NULL;
 677         const char *action_str = opts->action == REPLAY_REVERT ? "revert" : "pick";
 678         const char *subject;
 679         int subject_len;
 680
 681         for (cur = todo_list; cur; cur = cur->next) {
 682                 sha1_abbrev = find_unique_abbrev(cur->item->object.sha1, DEFAULT_ABBREV);
 683                 subject_len = find_commit_subject(cur->item->buffer, &subject);
 684                 strbuf_addf(buf, "%s %s %.*s\n", action_str, sha1_abbrev,
 685                         subject_len, subject);
 686         }
 687         return 0;
 688 }
 689
 690 static struct commit *parse_insn_line(char *bol, char *eol, struct replay_opts *opts)
 691 {
 692         unsigned char commit_sha1[20];
 693         enum replay_action action;
 694         char *end_of_object_name;
 695         int saved, status, padding;
 696
 697         if (!prefixcmp(bol, "pick")) {
 698                 action = REPLAY_PICK;
 699                 bol += strlen("pick");
 700         } else if (!prefixcmp(bol, "revert")) {
 701                 action = REPLAY_REVERT;
 702                 bol += strlen("revert");
 703         } else
 704                 return NULL;
 705
 706         /* Eat up extra spaces/ tabs before object name */
 707         padding = strspn(bol, " \t");
 708         if (!padding)
 709                 return NULL;
 710         bol += padding;
 711
 712         end_of_object_name = bol + strcspn(bol, " \t\n");
 713         saved = *end_of_object_name;
 714         *end_of_object_name = '\0';
 715         status = get_sha1(bol, commit_sha1);
 716         *end_of_object_name = saved;
 717
 718         /*
 719          * Verify that the action matches up with the one in
 720          * opts; we don't support arbitrary instructions
 721          */
 722         if (action != opts->action) {
 723                 const char *action_str;
 724                 action_str = action == REPLAY_REVERT ? "revert" : "cherry-pick";
 725                 error(_("Cannot %s during a %s"), action_str, action_name(opts));
 726                 return NULL;
 727         }
 728
 729         if (status < 0)
 730                 return NULL;
 731
 732         return lookup_commit_reference(commit_sha1);
 733 }
 734
 735 static int parse_insn_buffer(char *buf, struct commit_list **todo_list,
 736                         struct replay_opts *opts)
 737 {
 738         struct commit_list **next = todo_list;
 739         struct commit *commit;
 740         char *p = buf;
 741         int i;
 742
 743         for (i = 1; *p; i++) {
 744                 char *eol = strchrnul(p, '\n');
 745                 commit = parse_insn_line(p, eol, opts);
 746                 if (!commit)
 747                         return error(_("Could not parse line %d."), i);
 748                 next = commit_list_append(commit, next);
 749                 p = *eol ? eol + 1 : eol;
 750         }
 751         if (!*todo_list)
 752                 return error(_("No commits parsed."));
 753         return 0;
 754 }
 755
 756 static void read_populate_todo(struct commit_list **todo_list,
 757                         struct replay_opts *opts)
 758 {
 759         const char *todo_file = git_path(SEQ_TODO_FILE);
 760         struct strbuf buf = STRBUF_INIT;
 761         int fd, res;
 762
 763         fd = open(todo_file, O_RDONLY);
 764         if (fd < 0)
 765                 die_errno(_("Could not open %s"), todo_file);
 766         if (strbuf_read(&buf, fd, 0) < 0) {
 767                 close(fd);
 768                 strbuf_release(&buf);
 769                 die(_("Could not read %s."), todo_file);
 770         }
 771         close(fd);
 772
 773         res = parse_insn_buffer(buf.buf, todo_list, opts);
 774         strbuf_release(&buf);
 775         if (res)
 776                 die(_("Unusable instruction sheet: %s"), todo_file);
 777 }
 778
 779 static int populate_opts_cb(const char *key, const char *value, void *data)
 780 {
 781         struct replay_opts *opts = data;
 782         int error_flag = 1;
 783
 784         if (!value)
 785                 error_flag = 0;
 786         else if (!strcmp(key, "options.no-commit"))
 787                 opts->no_commit = git_config_bool_or_int(key, value, &error_flag);
 788         else if (!strcmp(key, "options.edit"))
 789                 opts->edit = git_config_bool_or_int(key, value, &error_flag);
 790         else if (!strcmp(key, "options.signoff"))
 791                 opts->signoff = git_config_bool_or_int(key, value, &error_flag);
 792         else if (!strcmp(key, "options.record-origin"))
 793                 opts->record_origin = git_config_bool_or_int(key, value, &error_flag);
 794         else if (!strcmp(key, "options.allow-ff"))
 795                 opts->allow_ff = git_config_bool_or_int(key, value, &error_flag);
 796         else if (!strcmp(key, "options.mainline"))
 797                 opts->mainline = git_config_int(key, value);
 798         else if (!strcmp(key, "options.strategy"))
 799                 git_config_string(&opts->strategy, key, value);
 800         else if (!strcmp(key, "options.strategy-option")) {
 801                 ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
 802                 opts->xopts[opts->xopts_nr++] = xstrdup(value);
 803         } else
 804                 return error(_("Invalid key: %s"), key);
 805
 806         if (!error_flag)
 807                 return error(_("Invalid value for %s: %s"), key, value);
 808
 809         return 0;
 810 }
 811
 812 static void read_populate_opts(struct replay_opts **opts_ptr)
 813 {
 814         const char *opts_file = git_path(SEQ_OPTS_FILE);
 815
 816         if (!file_exists(opts_file))
 817                 return;
 818         if (git_config_from_file(populate_opts_cb, opts_file, *opts_ptr) < 0)
 819                 die(_("Malformed options sheet: %s"), opts_file);
 820 }
 821
 822 static void walk_revs_populate_todo(struct commit_list **todo_list,
 823                                 struct replay_opts *opts)
 824 {
 825         struct commit *commit;
 826         struct commit_list **next;
 827
 828         prepare_revs(opts);
 829
 830         next = todo_list;
 831         while ((commit = get_revision(opts->revs)))
 832                 next = commit_list_append(commit, next);
 833 }
 834
 835 static int create_seq_dir(void)
 836 {
 837         const char *seq_dir = git_path(SEQ_DIR);
 838
 839         if (file_exists(seq_dir)) {
 840                 error(_("a cherry-pick or revert is already in progress"));
 841                 advise(_("try \"git cherry-pick (--continue | --quit | --abort)\""));
 842                 return -1;
 843         }
 844         else if (mkdir(seq_dir, 0777) < 0)
 845                 die_errno(_("Could not create sequencer directory %s"), seq_dir);
 846         return 0;
 847 }
 848
 849 static void save_head(const char *head)
 850 {
 851         const char *head_file = git_path(SEQ_HEAD_FILE);
 852         static struct lock_file head_lock;
 853         struct strbuf buf = STRBUF_INIT;
 854         int fd;
 855
 856         fd = hold_lock_file_for_update(&head_lock, head_file, LOCK_DIE_ON_ERROR);
 857         strbuf_addf(&buf, "%s\n", head);
 858         if (write_in_full(fd, buf.buf, buf.len) < 0)
 859                 die_errno(_("Could not write to %s"), head_file);
 860         if (commit_lock_file(&head_lock) < 0)
 861                 die(_("Error wrapping up %s."), head_file);
 862 }
 863
 864 static int reset_for_rollback(const unsigned char *sha1)
 865 {
 866         const char *argv[4];    /* reset --merge <arg> + NULL */
 867         argv[0] = "reset";
 868         argv[1] = "--merge";
 869         argv[2] = sha1_to_hex(sha1);
 870         argv[3] = NULL;
 871         return run_command_v_opt(argv, RUN_GIT_CMD);
 872 }
 873
 874 static int rollback_single_pick(void)
 875 {
 876         unsigned char head_sha1[20];
 877
 878         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
 879             !file_exists(git_path("REVERT_HEAD")))
 880                 return error(_("no cherry-pick or revert in progress"));
 881         if (read_ref_full("HEAD", head_sha1, 0, NULL))
 882                 return error(_("cannot resolve HEAD"));
 883         if (is_null_sha1(head_sha1))
 884                 return error(_("cannot abort from a branch yet to be born"));
 885         return reset_for_rollback(head_sha1);
 886 }
 887
 888 static int sequencer_rollback(struct replay_opts *opts)
 889 {
 890         const char *filename;
 891         FILE *f;
 892         unsigned char sha1[20];
 893         struct strbuf buf = STRBUF_INIT;
 894
 895         filename = git_path(SEQ_HEAD_FILE);
 896         f = fopen(filename, "r");
 897         if (!f && errno == ENOENT) {
 898                 /*
 899                  * There is no multiple-cherry-pick in progress.
 900                  * If CHERRY_PICK_HEAD or REVERT_HEAD indicates
 901                  * a single-cherry-pick in progress, abort that.
 902                  */
 903                 return rollback_single_pick();
 904         }
 905         if (!f)
 906                 return error(_("cannot open %s: %s"), filename,
 907                                                 strerror(errno));
 908         if (strbuf_getline(&buf, f, '\n')) {
 909                 error(_("cannot read %s: %s"), filename, ferror(f) ?
 910                         strerror(errno) : _("unexpected end of file"));
 911                 fclose(f);
 912                 goto fail;
 913         }
 914         fclose(f);
 915         if (get_sha1_hex(buf.buf, sha1) || buf.buf[40] != '\0') {
 916                 error(_("stored pre-cherry-pick HEAD file '%s' is corrupt"),
 917                         filename);
 918                 goto fail;
 919         }
 920         if (reset_for_rollback(sha1))
 921                 goto fail;
 922         remove_sequencer_state();
 923         strbuf_release(&buf);
 924         return 0;
 925 fail:
 926         strbuf_release(&buf);
 927         return -1;
 928 }
 929
 930 static void save_todo(struct commit_list *todo_list, struct replay_opts *opts)
 931 {
 932         const char *todo_file = git_path(SEQ_TODO_FILE);
 933         static struct lock_file todo_lock;
 934         struct strbuf buf = STRBUF_INIT;
 935         int fd;
 936
 937         fd = hold_lock_file_for_update(&todo_lock, todo_file, LOCK_DIE_ON_ERROR);
 938         if (format_todo(&buf, todo_list, opts) < 0)
 939                 die(_("Could not format %s."), todo_file);
 940         if (write_in_full(fd, buf.buf, buf.len) < 0) {
 941                 strbuf_release(&buf);
 942                 die_errno(_("Could not write to %s"), todo_file);
 943         }
 944         if (commit_lock_file(&todo_lock) < 0) {
 945                 strbuf_release(&buf);
 946                 die(_("Error wrapping up %s."), todo_file);
 947         }
 948         strbuf_release(&buf);
 949 }
 950
 951 static void save_opts(struct replay_opts *opts)
 952 {
 953         const char *opts_file = git_path(SEQ_OPTS_FILE);
 954
 955         if (opts->no_commit)
 956                 git_config_set_in_file(opts_file, "options.no-commit", "true");
 957         if (opts->edit)
 958                 git_config_set_in_file(opts_file, "options.edit", "true");
 959         if (opts->signoff)
 960                 git_config_set_in_file(opts_file, "options.signoff", "true");
 961         if (opts->record_origin)
 962                 git_config_set_in_file(opts_file, "options.record-origin", "true");
 963         if (opts->allow_ff)
 964                 git_config_set_in_file(opts_file, "options.allow-ff", "true");
 965         if (opts->mainline) {
 966                 struct strbuf buf = STRBUF_INIT;
 967                 strbuf_addf(&buf, "%d", opts->mainline);
 968                 git_config_set_in_file(opts_file, "options.mainline", buf.buf);
 969                 strbuf_release(&buf);
 970         }
 971         if (opts->strategy)
 972                 git_config_set_in_file(opts_file, "options.strategy", opts->strategy);
 973         if (opts->xopts) {
 974                 int i;
 975                 for (i = 0; i < opts->xopts_nr; i++)
 976                         git_config_set_multivar_in_file(opts_file,
 977                                                         "options.strategy-option",
 978                                                         opts->xopts[i], "^$", 0);
 979         }
 980 }
 981
 982 static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
 983 {
 984         struct commit_list *cur;
 985         int res;
 986
 987         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
 988         if (opts->allow_ff)
 989                 assert(!(opts->signoff || opts->no_commit ||
 990                                 opts->record_origin || opts->edit));
 991         read_and_refresh_cache(opts);
 992
 993         for (cur = todo_list; cur; cur = cur->next) {
 994                 save_todo(cur, opts);
 995                 res = do_pick_commit(cur->item, opts);
 996                 if (res)
 997                         return res;
 998         }
 999
1000         /*
1001          * Sequence of picks finished successfully; cleanup by
1002          * removing the .git/sequencer directory
1003          */
1004         remove_sequencer_state();
1005         return 0;
1006 }
1007
1008 static int continue_single_pick(void)
1009 {
1010         const char *argv[] = { "commit", NULL };
1011
1012         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
1013             !file_exists(git_path("REVERT_HEAD")))
1014                 return error(_("no cherry-pick or revert in progress"));
1015         return run_command_v_opt(argv, RUN_GIT_CMD);
1016 }
1017
1018 static int sequencer_continue(struct replay_opts *opts)
1019 {
1020         struct commit_list *todo_list = NULL;
1021
1022         if (!file_exists(git_path(SEQ_TODO_FILE)))
1023                 return continue_single_pick();
1024         read_populate_opts(&opts);
1025         read_populate_todo(&todo_list, opts);
1026
1027         /* Verify that the conflict has been resolved */
1028         if (file_exists(git_path("CHERRY_PICK_HEAD")) ||
1029             file_exists(git_path("REVERT_HEAD"))) {
1030                 int ret = continue_single_pick();
1031                 if (ret)
1032                         return ret;
1033         }
1034         if (index_differs_from("HEAD", 0))
1035                 return error_dirty_index(opts);
1036         todo_list = todo_list->next;
1037         return pick_commits(todo_list, opts);
1038 }
1039
1040 static int single_pick(struct commit *cmit, struct replay_opts *opts)
1041 {
1042         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
1043         return do_pick_commit(cmit, opts);
1044 }
1045
1046 int sequencer_pick_revisions(struct replay_opts *opts)
1047 {
1048         struct commit_list *todo_list = NULL;
1049         unsigned char sha1[20];
1050
1051         if (opts->subcommand == REPLAY_NONE)
1052                 assert(opts->revs);
1053
1054         read_and_refresh_cache(opts);
1055
1056         /*
1057          * Decide what to do depending on the arguments; a fresh
1058          * cherry-pick should be handled differently from an existing
1059          * one that is being continued
1060          */
1061         if (opts->subcommand == REPLAY_REMOVE_STATE) {
1062                 remove_sequencer_state();
1063                 return 0;
1064         }
1065         if (opts->subcommand == REPLAY_ROLLBACK)
1066                 return sequencer_rollback(opts);
1067         if (opts->subcommand == REPLAY_CONTINUE)
1068                 return sequencer_continue(opts);
1069
1070         /*
1071          * If we were called as "git cherry-pick <commit>", just
1072          * cherry-pick/revert it, set CHERRY_PICK_HEAD /
1073          * REVERT_HEAD, and don't touch the sequencer state.
1074          * This means it is possible to cherry-pick in the middle
1075          * of a cherry-pick sequence.
1076          */
1077         if (opts->revs->cmdline.nr == 1 &&
1078             opts->revs->cmdline.rev->whence == REV_CMD_REV &&
1079             opts->revs->no_walk &&
1080             !opts->revs->cmdline.rev->flags) {
1081                 struct commit *cmit;
1082                 if (prepare_revision_walk(opts->revs))
1083                         die(_("revision walk setup failed"));
1084                 cmit = get_revision(opts->revs);
1085                 if (!cmit || get_revision(opts->revs))
1086                         die("BUG: expected exactly one commit from walk");
1087                 return single_pick(cmit, opts);
1088         }
1089
1090         /*
1091          * Start a new cherry-pick/ revert sequence; but
1092          * first, make sure that an existing one isn't in
1093          * progress
1094          */
1095
1096         walk_revs_populate_todo(&todo_list, opts);
1097         if (create_seq_dir() < 0)
1098                 return -1;
1099         if (get_sha1("HEAD", sha1)) {
1100                 if (opts->action == REPLAY_REVERT)
1101                         return error(_("Can't revert as initial commit"));
1102                 return error(_("Can't cherry-pick into empty head"));
1103         }
1104         save_head(sha1_to_hex(sha1));
1105         save_opts(opts);
1106         return pick_commits(todo_list, opts);
1107 }
1108
1109 void append_signoff(struct strbuf *msgbuf, int ignore_footer, unsigned flag)
1110 {
1111         unsigned no_dup_sob = flag & APPEND_SIGNOFF_DEDUP;
1112         struct strbuf sob = STRBUF_INIT;
1113         int has_footer;
1114
1115         strbuf_addstr(&sob, sign_off_header);
1116         strbuf_addstr(&sob, fmt_name(getenv("GIT_COMMITTER_NAME"),
1117                                 getenv("GIT_COMMITTER_EMAIL")));
1118         strbuf_addch(&sob, '\n');
1119
1120         /*
1121          * If the whole message buffer is equal to the sob, pretend that we
1122          * found a conforming footer with a matching sob
1123          */
1124         if (msgbuf->len - ignore_footer == sob.len &&
1125             !strncmp(msgbuf->buf, sob.buf, sob.len))
1126                 has_footer = 3;
1127         else
1128                 has_footer = has_conforming_footer(msgbuf, &sob, ignore_footer);
1129
1130         if (!has_footer) {
1131                 const char *append_newlines = NULL;
1132                 size_t len = msgbuf->len - ignore_footer;
1133
1134                 if (!len) {
1135                         /*
1136                          * The buffer is completely empty.  Leave foom for
1137                          * the title and body to be filled in by the user.
1138                          */
1139                         append_newlines = "\n\n";
1140                 } else if (msgbuf->buf[len - 1] != '\n') {
1141                         /*
1142                          * Incomplete line.  Complete the line and add a
1143                          * blank one so that there is an empty line between
1144                          * the message body and the sob.
1145                          */
1146                         append_newlines = "\n\n";
1147                 } else if (len == 1) {
1148                         /*
1149                          * Buffer contains a single newline.  Add another
1150                          * so that we leave room for the title and body.
1151                          */
1152                         append_newlines = "\n";
1153                 } else if (msgbuf->buf[len - 2] != '\n') {
1154                         /*
1155                          * Buffer ends with a single newline.  Add another
1156                          * so that there is an empty line between the message
1157                          * body and the sob.
1158                          */
1159                         append_newlines = "\n";
1160                 } /* else, the buffer already ends with two newlines. */
1161
1162                 if (append_newlines)
1163                         strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0,
1164                                 append_newlines, strlen(append_newlines));
1165         }
1166
1167         if (has_footer != 3 && (!no_dup_sob || has_footer != 2))
1168                 strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0,
1169                                 sob.buf, sob.len);
1170
1171         strbuf_release(&sob);
1172 }