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                 starts_with(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 (starts_with(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,
 283                                            0, NULL);
 284         strbuf_addf(&sb, "%s: fast-forward", action_name(opts));
 285         ret = write_ref_sha1(ref_lock, to, sb.buf);
 286         strbuf_release(&sb);
 287         return ret;
 288 }
 289
 290 static int do_recursive_merge(struct commit *base, struct commit *next,
 291                               const char *base_label, const char *next_label,
 292                               unsigned char *head, struct strbuf *msgbuf,
 293                               struct replay_opts *opts)
 294 {
 295         struct merge_options o;
 296         struct tree *result, *next_tree, *base_tree, *head_tree;
 297         int clean, index_fd;
 298         const char **xopt;
 299         static struct lock_file index_lock;
 300
 301         index_fd = hold_locked_index(&index_lock, 1);
 302
 303         read_cache();
 304
 305         init_merge_options(&o);
 306         o.ancestor = base ? base_label : "(empty tree)";
 307         o.branch1 = "HEAD";
 308         o.branch2 = next ? next_label : "(empty tree)";
 309
 310         head_tree = parse_tree_indirect(head);
 311         next_tree = next ? next->tree : empty_tree();
 312         base_tree = base ? base->tree : empty_tree();
 313
 314         for (xopt = opts->xopts; xopt != opts->xopts + opts->xopts_nr; xopt++)
 315                 parse_merge_opt(&o, *xopt);
 316
 317         clean = merge_trees(&o,
 318                             head_tree,
 319                             next_tree, base_tree, &result);
 320
 321         if (active_cache_changed &&
 322             (write_cache(index_fd, active_cache, active_nr) ||
 323              commit_locked_index(&index_lock)))
 324                 /* TRANSLATORS: %s will be "revert" or "cherry-pick" */
 325                 die(_("%s: Unable to write new index file"), action_name(opts));
 326         rollback_lock_file(&index_lock);
 327
 328         if (opts->signoff)
 329                 append_signoff(msgbuf, 0, 0);
 330
 331         if (!clean) {
 332                 int i;
 333                 strbuf_addstr(msgbuf, "\nConflicts:\n");
 334                 for (i = 0; i < active_nr;) {
 335                         const struct cache_entry *ce = active_cache[i++];
 336                         if (ce_stage(ce)) {
 337                                 strbuf_addch(msgbuf, '\t');
 338                                 strbuf_addstr(msgbuf, ce->name);
 339                                 strbuf_addch(msgbuf, '\n');
 340                                 while (i < active_nr && !strcmp(ce->name,
 341                                                 active_cache[i]->name))
 342                                         i++;
 343                         }
 344                 }
 345         }
 346
 347         return !clean;
 348 }
 349
 350 static int is_index_unchanged(void)
 351 {
 352         unsigned char head_sha1[20];
 353         struct commit *head_commit;
 354
 355         if (!resolve_ref_unsafe("HEAD", head_sha1, 1, NULL))
 356                 return error(_("Could not resolve HEAD commit\n"));
 357
 358         head_commit = lookup_commit(head_sha1);
 359
 360         /*
 361          * If head_commit is NULL, check_commit, called from
 362          * lookup_commit, would have indicated that head_commit is not
 363          * a commit object already.  parse_commit() will return failure
 364          * without further complaints in such a case.  Otherwise, if
 365          * the commit is invalid, parse_commit() will complain.  So
 366          * there is nothing for us to say here.  Just return failure.
 367          */
 368         if (parse_commit(head_commit))
 369                 return -1;
 370
 371         if (!active_cache_tree)
 372                 active_cache_tree = cache_tree();
 373
 374         if (!cache_tree_fully_valid(active_cache_tree))
 375                 if (cache_tree_update(active_cache_tree,
 376                                       (const struct cache_entry * const *)active_cache,
 377                                       active_nr, 0))
 378                         return error(_("Unable to update cache tree\n"));
 379
 380         return !hashcmp(active_cache_tree->sha1, head_commit->tree->object.sha1);
 381 }
 382
 383 /*
 384  * If we are cherry-pick, and if the merge did not result in
 385  * hand-editing, we will hit this commit and inherit the original
 386  * author date and name.
 387  * If we are revert, or if our cherry-pick results in a hand merge,
 388  * we had better say that the current user is responsible for that.
 389  */
 390 static int run_git_commit(const char *defmsg, struct replay_opts *opts,
 391                           int allow_empty)
 392 {
 393         struct argv_array array;
 394         int rc;
 395
 396         argv_array_init(&array);
 397         argv_array_push(&array, "commit");
 398         argv_array_push(&array, "-n");
 399
 400         if (opts->signoff)
 401                 argv_array_push(&array, "-s");
 402         if (!opts->edit) {
 403                 argv_array_push(&array, "-F");
 404                 argv_array_push(&array, defmsg);
 405         }
 406
 407         if (allow_empty)
 408                 argv_array_push(&array, "--allow-empty");
 409
 410         if (opts->allow_empty_message)
 411                 argv_array_push(&array, "--allow-empty-message");
 412
 413         rc = run_command_v_opt(array.argv, RUN_GIT_CMD);
 414         argv_array_clear(&array);
 415         return rc;
 416 }
 417
 418 static int is_original_commit_empty(struct commit *commit)
 419 {
 420         const unsigned char *ptree_sha1;
 421
 422         if (parse_commit(commit))
 423                 return error(_("Could not parse commit %s\n"),
 424                              sha1_to_hex(commit->object.sha1));
 425         if (commit->parents) {
 426                 struct commit *parent = commit->parents->item;
 427                 if (parse_commit(parent))
 428                         return error(_("Could not parse parent commit %s\n"),
 429                                 sha1_to_hex(parent->object.sha1));
 430                 ptree_sha1 = parent->tree->object.sha1;
 431         } else {
 432                 ptree_sha1 = EMPTY_TREE_SHA1_BIN; /* commit is root */
 433         }
 434
 435         return !hashcmp(ptree_sha1, commit->tree->object.sha1);
 436 }
 437
 438 /*
 439  * Do we run "git commit" with "--allow-empty"?
 440  */
 441 static int allow_empty(struct replay_opts *opts, struct commit *commit)
 442 {
 443         int index_unchanged, empty_commit;
 444
 445         /*
 446          * Three cases:
 447          *
 448          * (1) we do not allow empty at all and error out.
 449          *
 450          * (2) we allow ones that were initially empty, but
 451          * forbid the ones that become empty;
 452          *
 453          * (3) we allow both.
 454          */
 455         if (!opts->allow_empty)
 456                 return 0; /* let "git commit" barf as necessary */
 457
 458         index_unchanged = is_index_unchanged();
 459         if (index_unchanged < 0)
 460                 return index_unchanged;
 461         if (!index_unchanged)
 462                 return 0; /* we do not have to say --allow-empty */
 463
 464         if (opts->keep_redundant_commits)
 465                 return 1;
 466
 467         empty_commit = is_original_commit_empty(commit);
 468         if (empty_commit < 0)
 469                 return empty_commit;
 470         if (!empty_commit)
 471                 return 0;
 472         else
 473                 return 1;
 474 }
 475
 476 static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
 477 {
 478         unsigned char head[20];
 479         struct commit *base, *next, *parent;
 480         const char *base_label, *next_label;
 481         struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
 482         char *defmsg = NULL;
 483         struct strbuf msgbuf = STRBUF_INIT;
 484         int res, unborn = 0, allow;
 485
 486         if (opts->no_commit) {
 487                 /*
 488                  * We do not intend to commit immediately.  We just want to
 489                  * merge the differences in, so let's compute the tree
 490                  * that represents the "current" state for merge-recursive
 491                  * to work on.
 492                  */
 493                 if (write_cache_as_tree(head, 0, NULL))
 494                         die (_("Your index file is unmerged."));
 495         } else {
 496                 unborn = get_sha1("HEAD", head);
 497                 if (unborn)
 498                         hashcpy(head, EMPTY_TREE_SHA1_BIN);
 499                 if (index_differs_from(unborn ? EMPTY_TREE_SHA1_HEX : "HEAD", 0))
 500                         return error_dirty_index(opts);
 501         }
 502         discard_cache();
 503
 504         if (!commit->parents) {
 505                 parent = NULL;
 506         }
 507         else if (commit->parents->next) {
 508                 /* Reverting or cherry-picking a merge commit */
 509                 int cnt;
 510                 struct commit_list *p;
 511
 512                 if (!opts->mainline)
 513                         return error(_("Commit %s is a merge but no -m option was given."),
 514                                 sha1_to_hex(commit->object.sha1));
 515
 516                 for (cnt = 1, p = commit->parents;
 517                      cnt != opts->mainline && p;
 518                      cnt++)
 519                         p = p->next;
 520                 if (cnt != opts->mainline || !p)
 521                         return error(_("Commit %s does not have parent %d"),
 522                                 sha1_to_hex(commit->object.sha1), opts->mainline);
 523                 parent = p->item;
 524         } else if (0 < opts->mainline)
 525                 return error(_("Mainline was specified but commit %s is not a merge."),
 526                         sha1_to_hex(commit->object.sha1));
 527         else
 528                 parent = commit->parents->item;
 529
 530         if (opts->allow_ff &&
 531             ((parent && !hashcmp(parent->object.sha1, head)) ||
 532              (!parent && unborn)))
 533                 return fast_forward_to(commit->object.sha1, head, unborn, opts);
 534
 535         if (parent && parse_commit(parent) < 0)
 536                 /* TRANSLATORS: The first %s will be "revert" or
 537                    "cherry-pick", the second %s a SHA1 */
 538                 return error(_("%s: cannot parse parent commit %s"),
 539                         action_name(opts), sha1_to_hex(parent->object.sha1));
 540
 541         if (get_message(commit, &msg) != 0)
 542                 return error(_("Cannot get commit message for %s"),
 543                         sha1_to_hex(commit->object.sha1));
 544
 545         /*
 546          * "commit" is an existing commit.  We would want to apply
 547          * the difference it introduces since its first parent "prev"
 548          * on top of the current HEAD if we are cherry-pick.  Or the
 549          * reverse of it if we are revert.
 550          */
 551
 552         defmsg = git_pathdup("MERGE_MSG");
 553
 554         if (opts->action == REPLAY_REVERT) {
 555                 base = commit;
 556                 base_label = msg.label;
 557                 next = parent;
 558                 next_label = msg.parent_label;
 559                 strbuf_addstr(&msgbuf, "Revert \"");
 560                 strbuf_addstr(&msgbuf, msg.subject);
 561                 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
 562                 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 563
 564                 if (commit->parents && commit->parents->next) {
 565                         strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
 566                         strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
 567                 }
 568                 strbuf_addstr(&msgbuf, ".\n");
 569         } else {
 570                 const char *p;
 571
 572                 base = parent;
 573                 base_label = msg.parent_label;
 574                 next = commit;
 575                 next_label = msg.label;
 576
 577                 /*
 578                  * Append the commit log message to msgbuf; it starts
 579                  * after the tree, parent, author, committer
 580                  * information followed by "\n\n".
 581                  */
 582                 p = strstr(msg.message, "\n\n");
 583                 if (p) {
 584                         p += 2;
 585                         strbuf_addstr(&msgbuf, p);
 586                 }
 587
 588                 if (opts->record_origin) {
 589                         if (!has_conforming_footer(&msgbuf, NULL, 0))
 590                                 strbuf_addch(&msgbuf, '\n');
 591                         strbuf_addstr(&msgbuf, cherry_picked_prefix);
 592                         strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 593                         strbuf_addstr(&msgbuf, ")\n");
 594                 }
 595         }
 596
 597         if (!opts->strategy || !strcmp(opts->strategy, "recursive") || opts->action == REPLAY_REVERT) {
 598                 res = do_recursive_merge(base, next, base_label, next_label,
 599                                          head, &msgbuf, opts);
 600                 write_message(&msgbuf, defmsg);
 601         } else {
 602                 struct commit_list *common = NULL;
 603                 struct commit_list *remotes = NULL;
 604
 605                 write_message(&msgbuf, defmsg);
 606
 607                 commit_list_insert(base, &common);
 608                 commit_list_insert(next, &remotes);
 609                 res = try_merge_command(opts->strategy, opts->xopts_nr, opts->xopts,
 610                                         common, sha1_to_hex(head), remotes);
 611                 free_commit_list(common);
 612                 free_commit_list(remotes);
 613         }
 614
 615         /*
 616          * If the merge was clean or if it failed due to conflict, we write
 617          * CHERRY_PICK_HEAD for the subsequent invocation of commit to use.
 618          * However, if the merge did not even start, then we don't want to
 619          * write it at all.
 620          */
 621         if (opts->action == REPLAY_PICK && !opts->no_commit && (res == 0 || res == 1))
 622                 write_cherry_pick_head(commit, "CHERRY_PICK_HEAD");
 623         if (opts->action == REPLAY_REVERT && ((opts->no_commit && res == 0) || res == 1))
 624                 write_cherry_pick_head(commit, "REVERT_HEAD");
 625
 626         if (res) {
 627                 error(opts->action == REPLAY_REVERT
 628                       ? _("could not revert %s... %s")
 629                       : _("could not apply %s... %s"),
 630                       find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV),
 631                       msg.subject);
 632                 print_advice(res == 1, opts);
 633                 rerere(opts->allow_rerere_auto);
 634                 goto leave;
 635         }
 636
 637         allow = allow_empty(opts, commit);
 638         if (allow < 0) {
 639                 res = allow;
 640                 goto leave;
 641         }
 642         if (!opts->no_commit)
 643                 res = run_git_commit(defmsg, opts, allow);
 644
 645 leave:
 646         free_message(&msg);
 647         free(defmsg);
 648
 649         return res;
 650 }
 651
 652 static void prepare_revs(struct replay_opts *opts)
 653 {
 654         /*
 655          * picking (but not reverting) ranges (but not individual revisions)
 656          * should be done in reverse
 657          */
 658         if (opts->action == REPLAY_PICK && !opts->revs->no_walk)
 659                 opts->revs->reverse ^= 1;
 660
 661         if (prepare_revision_walk(opts->revs))
 662                 die(_("revision walk setup failed"));
 663
 664         if (!opts->revs->commits)
 665                 die(_("empty commit set passed"));
 666 }
 667
 668 static void read_and_refresh_cache(struct replay_opts *opts)
 669 {
 670         static struct lock_file index_lock;
 671         int index_fd = hold_locked_index(&index_lock, 0);
 672         if (read_index_preload(&the_index, NULL) < 0)
 673                 die(_("git %s: failed to read the index"), action_name(opts));
 674         refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
 675         if (the_index.cache_changed) {
 676                 if (write_index(&the_index, index_fd) ||
 677                     commit_locked_index(&index_lock))
 678                         die(_("git %s: failed to refresh the index"), action_name(opts));
 679         }
 680         rollback_lock_file(&index_lock);
 681 }
 682
 683 static int format_todo(struct strbuf *buf, struct commit_list *todo_list,
 684                 struct replay_opts *opts)
 685 {
 686         struct commit_list *cur = NULL;
 687         const char *sha1_abbrev = NULL;
 688         const char *action_str = opts->action == REPLAY_REVERT ? "revert" : "pick";
 689         const char *subject;
 690         int subject_len;
 691
 692         for (cur = todo_list; cur; cur = cur->next) {
 693                 sha1_abbrev = find_unique_abbrev(cur->item->object.sha1, DEFAULT_ABBREV);
 694                 subject_len = find_commit_subject(cur->item->buffer, &subject);
 695                 strbuf_addf(buf, "%s %s %.*s\n", action_str, sha1_abbrev,
 696                         subject_len, subject);
 697         }
 698         return 0;
 699 }
 700
 701 static struct commit *parse_insn_line(char *bol, char *eol, struct replay_opts *opts)
 702 {
 703         unsigned char commit_sha1[20];
 704         enum replay_action action;
 705         char *end_of_object_name;
 706         int saved, status, padding;
 707
 708         if (starts_with(bol, "pick")) {
 709                 action = REPLAY_PICK;
 710                 bol += strlen("pick");
 711         } else if (starts_with(bol, "revert")) {
 712                 action = REPLAY_REVERT;
 713                 bol += strlen("revert");
 714         } else
 715                 return NULL;
 716
 717         /* Eat up extra spaces/ tabs before object name */
 718         padding = strspn(bol, " \t");
 719         if (!padding)
 720                 return NULL;
 721         bol += padding;
 722
 723         end_of_object_name = bol + strcspn(bol, " \t\n");
 724         saved = *end_of_object_name;
 725         *end_of_object_name = '\0';
 726         status = get_sha1(bol, commit_sha1);
 727         *end_of_object_name = saved;
 728
 729         /*
 730          * Verify that the action matches up with the one in
 731          * opts; we don't support arbitrary instructions
 732          */
 733         if (action != opts->action) {
 734                 const char *action_str;
 735                 action_str = action == REPLAY_REVERT ? "revert" : "cherry-pick";
 736                 error(_("Cannot %s during a %s"), action_str, action_name(opts));
 737                 return NULL;
 738         }
 739
 740         if (status < 0)
 741                 return NULL;
 742
 743         return lookup_commit_reference(commit_sha1);
 744 }
 745
 746 static int parse_insn_buffer(char *buf, struct commit_list **todo_list,
 747                         struct replay_opts *opts)
 748 {
 749         struct commit_list **next = todo_list;
 750         struct commit *commit;
 751         char *p = buf;
 752         int i;
 753
 754         for (i = 1; *p; i++) {
 755                 char *eol = strchrnul(p, '\n');
 756                 commit = parse_insn_line(p, eol, opts);
 757                 if (!commit)
 758                         return error(_("Could not parse line %d."), i);
 759                 next = commit_list_append(commit, next);
 760                 p = *eol ? eol + 1 : eol;
 761         }
 762         if (!*todo_list)
 763                 return error(_("No commits parsed."));
 764         return 0;
 765 }
 766
 767 static void read_populate_todo(struct commit_list **todo_list,
 768                         struct replay_opts *opts)
 769 {
 770         const char *todo_file = git_path(SEQ_TODO_FILE);
 771         struct strbuf buf = STRBUF_INIT;
 772         int fd, res;
 773
 774         fd = open(todo_file, O_RDONLY);
 775         if (fd < 0)
 776                 die_errno(_("Could not open %s"), todo_file);
 777         if (strbuf_read(&buf, fd, 0) < 0) {
 778                 close(fd);
 779                 strbuf_release(&buf);
 780                 die(_("Could not read %s."), todo_file);
 781         }
 782         close(fd);
 783
 784         res = parse_insn_buffer(buf.buf, todo_list, opts);
 785         strbuf_release(&buf);
 786         if (res)
 787                 die(_("Unusable instruction sheet: %s"), todo_file);
 788 }
 789
 790 static int populate_opts_cb(const char *key, const char *value, void *data)
 791 {
 792         struct replay_opts *opts = data;
 793         int error_flag = 1;
 794
 795         if (!value)
 796                 error_flag = 0;
 797         else if (!strcmp(key, "options.no-commit"))
 798                 opts->no_commit = git_config_bool_or_int(key, value, &error_flag);
 799         else if (!strcmp(key, "options.edit"))
 800                 opts->edit = git_config_bool_or_int(key, value, &error_flag);
 801         else if (!strcmp(key, "options.signoff"))
 802                 opts->signoff = git_config_bool_or_int(key, value, &error_flag);
 803         else if (!strcmp(key, "options.record-origin"))
 804                 opts->record_origin = git_config_bool_or_int(key, value, &error_flag);
 805         else if (!strcmp(key, "options.allow-ff"))
 806                 opts->allow_ff = git_config_bool_or_int(key, value, &error_flag);
 807         else if (!strcmp(key, "options.mainline"))
 808                 opts->mainline = git_config_int(key, value);
 809         else if (!strcmp(key, "options.strategy"))
 810                 git_config_string(&opts->strategy, key, value);
 811         else if (!strcmp(key, "options.strategy-option")) {
 812                 ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
 813                 opts->xopts[opts->xopts_nr++] = xstrdup(value);
 814         } else
 815                 return error(_("Invalid key: %s"), key);
 816
 817         if (!error_flag)
 818                 return error(_("Invalid value for %s: %s"), key, value);
 819
 820         return 0;
 821 }
 822
 823 static void read_populate_opts(struct replay_opts **opts_ptr)
 824 {
 825         const char *opts_file = git_path(SEQ_OPTS_FILE);
 826
 827         if (!file_exists(opts_file))
 828                 return;
 829         if (git_config_from_file(populate_opts_cb, opts_file, *opts_ptr) < 0)
 830                 die(_("Malformed options sheet: %s"), opts_file);
 831 }
 832
 833 static void walk_revs_populate_todo(struct commit_list **todo_list,
 834                                 struct replay_opts *opts)
 835 {
 836         struct commit *commit;
 837         struct commit_list **next;
 838
 839         prepare_revs(opts);
 840
 841         next = todo_list;
 842         while ((commit = get_revision(opts->revs)))
 843                 next = commit_list_append(commit, next);
 844 }
 845
 846 static int create_seq_dir(void)
 847 {
 848         const char *seq_dir = git_path(SEQ_DIR);
 849
 850         if (file_exists(seq_dir)) {
 851                 error(_("a cherry-pick or revert is already in progress"));
 852                 advise(_("try \"git cherry-pick (--continue | --quit | --abort)\""));
 853                 return -1;
 854         }
 855         else if (mkdir(seq_dir, 0777) < 0)
 856                 die_errno(_("Could not create sequencer directory %s"), seq_dir);
 857         return 0;
 858 }
 859
 860 static void save_head(const char *head)
 861 {
 862         const char *head_file = git_path(SEQ_HEAD_FILE);
 863         static struct lock_file head_lock;
 864         struct strbuf buf = STRBUF_INIT;
 865         int fd;
 866
 867         fd = hold_lock_file_for_update(&head_lock, head_file, LOCK_DIE_ON_ERROR);
 868         strbuf_addf(&buf, "%s\n", head);
 869         if (write_in_full(fd, buf.buf, buf.len) < 0)
 870                 die_errno(_("Could not write to %s"), head_file);
 871         if (commit_lock_file(&head_lock) < 0)
 872                 die(_("Error wrapping up %s."), head_file);
 873 }
 874
 875 static int reset_for_rollback(const unsigned char *sha1)
 876 {
 877         const char *argv[4];    /* reset --merge <arg> + NULL */
 878         argv[0] = "reset";
 879         argv[1] = "--merge";
 880         argv[2] = sha1_to_hex(sha1);
 881         argv[3] = NULL;
 882         return run_command_v_opt(argv, RUN_GIT_CMD);
 883 }
 884
 885 static int rollback_single_pick(void)
 886 {
 887         unsigned char head_sha1[20];
 888
 889         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
 890             !file_exists(git_path("REVERT_HEAD")))
 891                 return error(_("no cherry-pick or revert in progress"));
 892         if (read_ref_full("HEAD", head_sha1, 0, NULL))
 893                 return error(_("cannot resolve HEAD"));
 894         if (is_null_sha1(head_sha1))
 895                 return error(_("cannot abort from a branch yet to be born"));
 896         return reset_for_rollback(head_sha1);
 897 }
 898
 899 static int sequencer_rollback(struct replay_opts *opts)
 900 {
 901         const char *filename;
 902         FILE *f;
 903         unsigned char sha1[20];
 904         struct strbuf buf = STRBUF_INIT;
 905
 906         filename = git_path(SEQ_HEAD_FILE);
 907         f = fopen(filename, "r");
 908         if (!f && errno == ENOENT) {
 909                 /*
 910                  * There is no multiple-cherry-pick in progress.
 911                  * If CHERRY_PICK_HEAD or REVERT_HEAD indicates
 912                  * a single-cherry-pick in progress, abort that.
 913                  */
 914                 return rollback_single_pick();
 915         }
 916         if (!f)
 917                 return error(_("cannot open %s: %s"), filename,
 918                                                 strerror(errno));
 919         if (strbuf_getline(&buf, f, '\n')) {
 920                 error(_("cannot read %s: %s"), filename, ferror(f) ?
 921                         strerror(errno) : _("unexpected end of file"));
 922                 fclose(f);
 923                 goto fail;
 924         }
 925         fclose(f);
 926         if (get_sha1_hex(buf.buf, sha1) || buf.buf[40] != '\0') {
 927                 error(_("stored pre-cherry-pick HEAD file '%s' is corrupt"),
 928                         filename);
 929                 goto fail;
 930         }
 931         if (reset_for_rollback(sha1))
 932                 goto fail;
 933         remove_sequencer_state();
 934         strbuf_release(&buf);
 935         return 0;
 936 fail:
 937         strbuf_release(&buf);
 938         return -1;
 939 }
 940
 941 static void save_todo(struct commit_list *todo_list, struct replay_opts *opts)
 942 {
 943         const char *todo_file = git_path(SEQ_TODO_FILE);
 944         static struct lock_file todo_lock;
 945         struct strbuf buf = STRBUF_INIT;
 946         int fd;
 947
 948         fd = hold_lock_file_for_update(&todo_lock, todo_file, LOCK_DIE_ON_ERROR);
 949         if (format_todo(&buf, todo_list, opts) < 0)
 950                 die(_("Could not format %s."), todo_file);
 951         if (write_in_full(fd, buf.buf, buf.len) < 0) {
 952                 strbuf_release(&buf);
 953                 die_errno(_("Could not write to %s"), todo_file);
 954         }
 955         if (commit_lock_file(&todo_lock) < 0) {
 956                 strbuf_release(&buf);
 957                 die(_("Error wrapping up %s."), todo_file);
 958         }
 959         strbuf_release(&buf);
 960 }
 961
 962 static void save_opts(struct replay_opts *opts)
 963 {
 964         const char *opts_file = git_path(SEQ_OPTS_FILE);
 965
 966         if (opts->no_commit)
 967                 git_config_set_in_file(opts_file, "options.no-commit", "true");
 968         if (opts->edit)
 969                 git_config_set_in_file(opts_file, "options.edit", "true");
 970         if (opts->signoff)
 971                 git_config_set_in_file(opts_file, "options.signoff", "true");
 972         if (opts->record_origin)
 973                 git_config_set_in_file(opts_file, "options.record-origin", "true");
 974         if (opts->allow_ff)
 975                 git_config_set_in_file(opts_file, "options.allow-ff", "true");
 976         if (opts->mainline) {
 977                 struct strbuf buf = STRBUF_INIT;
 978                 strbuf_addf(&buf, "%d", opts->mainline);
 979                 git_config_set_in_file(opts_file, "options.mainline", buf.buf);
 980                 strbuf_release(&buf);
 981         }
 982         if (opts->strategy)
 983                 git_config_set_in_file(opts_file, "options.strategy", opts->strategy);
 984         if (opts->xopts) {
 985                 int i;
 986                 for (i = 0; i < opts->xopts_nr; i++)
 987                         git_config_set_multivar_in_file(opts_file,
 988                                                         "options.strategy-option",
 989                                                         opts->xopts[i], "^$", 0);
 990         }
 991 }
 992
 993 static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
 994 {
 995         struct commit_list *cur;
 996         int res;
 997
 998         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
 999         if (opts->allow_ff)
1000                 assert(!(opts->signoff || opts->no_commit ||
1001                                 opts->record_origin || opts->edit));
1002         read_and_refresh_cache(opts);
1003
1004         for (cur = todo_list; cur; cur = cur->next) {
1005                 save_todo(cur, opts);
1006                 res = do_pick_commit(cur->item, opts);
1007                 if (res)
1008                         return res;
1009         }
1010
1011         /*
1012          * Sequence of picks finished successfully; cleanup by
1013          * removing the .git/sequencer directory
1014          */
1015         remove_sequencer_state();
1016         return 0;
1017 }
1018
1019 static int continue_single_pick(void)
1020 {
1021         const char *argv[] = { "commit", NULL };
1022
1023         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
1024             !file_exists(git_path("REVERT_HEAD")))
1025                 return error(_("no cherry-pick or revert in progress"));
1026         return run_command_v_opt(argv, RUN_GIT_CMD);
1027 }
1028
1029 static int sequencer_continue(struct replay_opts *opts)
1030 {
1031         struct commit_list *todo_list = NULL;
1032
1033         if (!file_exists(git_path(SEQ_TODO_FILE)))
1034                 return continue_single_pick();
1035         read_populate_opts(&opts);
1036         read_populate_todo(&todo_list, opts);
1037
1038         /* Verify that the conflict has been resolved */
1039         if (file_exists(git_path("CHERRY_PICK_HEAD")) ||
1040             file_exists(git_path("REVERT_HEAD"))) {
1041                 int ret = continue_single_pick();
1042                 if (ret)
1043                         return ret;
1044         }
1045         if (index_differs_from("HEAD", 0))
1046                 return error_dirty_index(opts);
1047         todo_list = todo_list->next;
1048         return pick_commits(todo_list, opts);
1049 }
1050
1051 static int single_pick(struct commit *cmit, struct replay_opts *opts)
1052 {
1053         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
1054         return do_pick_commit(cmit, opts);
1055 }
1056
1057 int sequencer_pick_revisions(struct replay_opts *opts)
1058 {
1059         struct commit_list *todo_list = NULL;
1060         unsigned char sha1[20];
1061         int i;
1062
1063         if (opts->subcommand == REPLAY_NONE)
1064                 assert(opts->revs);
1065
1066         read_and_refresh_cache(opts);
1067
1068         /*
1069          * Decide what to do depending on the arguments; a fresh
1070          * cherry-pick should be handled differently from an existing
1071          * one that is being continued
1072          */
1073         if (opts->subcommand == REPLAY_REMOVE_STATE) {
1074                 remove_sequencer_state();
1075                 return 0;
1076         }
1077         if (opts->subcommand == REPLAY_ROLLBACK)
1078                 return sequencer_rollback(opts);
1079         if (opts->subcommand == REPLAY_CONTINUE)
1080                 return sequencer_continue(opts);
1081
1082         for (i = 0; i < opts->revs->pending.nr; i++) {
1083                 unsigned char sha1[20];
1084                 const char *name = opts->revs->pending.objects[i].name;
1085
1086                 /* This happens when using --stdin. */
1087                 if (!strlen(name))
1088                         continue;
1089
1090                 if (!get_sha1(name, sha1)) {
1091                         if (!lookup_commit_reference_gently(sha1, 1)) {
1092                                 enum object_type type = sha1_object_info(sha1, NULL);
1093                                 die(_("%s: can't cherry-pick a %s"), name, typename(type));
1094                         }
1095                 } else
1096                         die(_("%s: bad revision"), name);
1097         }
1098
1099         /*
1100          * If we were called as "git cherry-pick <commit>", just
1101          * cherry-pick/revert it, set CHERRY_PICK_HEAD /
1102          * REVERT_HEAD, and don't touch the sequencer state.
1103          * This means it is possible to cherry-pick in the middle
1104          * of a cherry-pick sequence.
1105          */
1106         if (opts->revs->cmdline.nr == 1 &&
1107             opts->revs->cmdline.rev->whence == REV_CMD_REV &&
1108             opts->revs->no_walk &&
1109             !opts->revs->cmdline.rev->flags) {
1110                 struct commit *cmit;
1111                 if (prepare_revision_walk(opts->revs))
1112                         die(_("revision walk setup failed"));
1113                 cmit = get_revision(opts->revs);
1114                 if (!cmit || get_revision(opts->revs))
1115                         die("BUG: expected exactly one commit from walk");
1116                 return single_pick(cmit, opts);
1117         }
1118
1119         /*
1120          * Start a new cherry-pick/ revert sequence; but
1121          * first, make sure that an existing one isn't in
1122          * progress
1123          */
1124
1125         walk_revs_populate_todo(&todo_list, opts);
1126         if (create_seq_dir() < 0)
1127                 return -1;
1128         if (get_sha1("HEAD", sha1)) {
1129                 if (opts->action == REPLAY_REVERT)
1130                         return error(_("Can't revert as initial commit"));
1131                 return error(_("Can't cherry-pick into empty head"));
1132         }
1133         save_head(sha1_to_hex(sha1));
1134         save_opts(opts);
1135         return pick_commits(todo_list, opts);
1136 }
1137
1138 void append_signoff(struct strbuf *msgbuf, int ignore_footer, unsigned flag)
1139 {
1140         unsigned no_dup_sob = flag & APPEND_SIGNOFF_DEDUP;
1141         struct strbuf sob = STRBUF_INIT;
1142         int has_footer;
1143
1144         strbuf_addstr(&sob, sign_off_header);
1145         strbuf_addstr(&sob, fmt_name(getenv("GIT_COMMITTER_NAME"),
1146                                 getenv("GIT_COMMITTER_EMAIL")));
1147         strbuf_addch(&sob, '\n');
1148
1149         /*
1150          * If the whole message buffer is equal to the sob, pretend that we
1151          * found a conforming footer with a matching sob
1152          */
1153         if (msgbuf->len - ignore_footer == sob.len &&
1154             !strncmp(msgbuf->buf, sob.buf, sob.len))
1155                 has_footer = 3;
1156         else
1157                 has_footer = has_conforming_footer(msgbuf, &sob, ignore_footer);
1158
1159         if (!has_footer) {
1160                 const char *append_newlines = NULL;
1161                 size_t len = msgbuf->len - ignore_footer;
1162
1163                 if (!len) {
1164                         /*
1165                          * The buffer is completely empty.  Leave foom for
1166                          * the title and body to be filled in by the user.
1167                          */
1168                         append_newlines = "\n\n";
1169                 } else if (msgbuf->buf[len - 1] != '\n') {
1170                         /*
1171                          * Incomplete line.  Complete the line and add a
1172                          * blank one so that there is an empty line between
1173                          * the message body and the sob.
1174                          */
1175                         append_newlines = "\n\n";
1176                 } else if (len == 1) {
1177                         /*
1178                          * Buffer contains a single newline.  Add another
1179                          * so that we leave room for the title and body.
1180                          */
1181                         append_newlines = "\n";
1182                 } else if (msgbuf->buf[len - 2] != '\n') {
1183                         /*
1184                          * Buffer ends with a single newline.  Add another
1185                          * so that there is an empty line between the message
1186                          * body and the sob.
1187                          */
1188                         append_newlines = "\n";
1189                 } /* else, the buffer already ends with two newlines. */
1190
1191                 if (append_newlines)
1192                         strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0,
1193                                 append_newlines, strlen(append_newlines));
1194         }
1195
1196         if (has_footer != 3 && (!no_dup_sob || has_footer != 2))
1197                 strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0,
1198                                 sob.buf, sob.len);
1199
1200         strbuf_release(&sob);
1201 }