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