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,
 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 void append_conflicts_hint(struct strbuf *msgbuf)
 291 {
 292         int i;
 293
 294         strbuf_addstr(msgbuf, "\nConflicts:\n");
 295         for (i = 0; i < active_nr;) {
 296                 const struct cache_entry *ce = active_cache[i++];
 297                 if (ce_stage(ce)) {
 298                         strbuf_addch(msgbuf, '\t');
 299                         strbuf_addstr(msgbuf, ce->name);
 300                         strbuf_addch(msgbuf, '\n');
 301                         while (i < active_nr && !strcmp(ce->name,
 302                                                         active_cache[i]->name))
 303                                 i++;
 304                 }
 305         }
 306 }
 307
 308 static int do_recursive_merge(struct commit *base, struct commit *next,
 309                               const char *base_label, const char *next_label,
 310                               unsigned char *head, struct strbuf *msgbuf,
 311                               struct replay_opts *opts)
 312 {
 313         struct merge_options o;
 314         struct tree *result, *next_tree, *base_tree, *head_tree;
 315         int clean, index_fd;
 316         const char **xopt;
 317         static struct lock_file index_lock;
 318
 319         index_fd = hold_locked_index(&index_lock, 1);
 320
 321         read_cache();
 322
 323         init_merge_options(&o);
 324         o.ancestor = base ? base_label : "(empty tree)";
 325         o.branch1 = "HEAD";
 326         o.branch2 = next ? next_label : "(empty tree)";
 327
 328         head_tree = parse_tree_indirect(head);
 329         next_tree = next ? next->tree : empty_tree();
 330         base_tree = base ? base->tree : empty_tree();
 331
 332         for (xopt = opts->xopts; xopt != opts->xopts + opts->xopts_nr; xopt++)
 333                 parse_merge_opt(&o, *xopt);
 334
 335         clean = merge_trees(&o,
 336                             head_tree,
 337                             next_tree, base_tree, &result);
 338
 339         if (active_cache_changed &&
 340             (write_cache(index_fd, active_cache, active_nr) ||
 341              commit_locked_index(&index_lock)))
 342                 /* TRANSLATORS: %s will be "revert" or "cherry-pick" */
 343                 die(_("%s: Unable to write new index file"), action_name(opts));
 344         rollback_lock_file(&index_lock);
 345
 346         if (opts->signoff)
 347                 append_signoff(msgbuf, 0, 0);
 348
 349         if (!clean)
 350                 append_conflicts_hint(msgbuf);
 351
 352         return !clean;
 353 }
 354
 355 static int is_index_unchanged(void)
 356 {
 357         unsigned char head_sha1[20];
 358         struct commit *head_commit;
 359
 360         if (!resolve_ref_unsafe("HEAD", head_sha1, 1, NULL))
 361                 return error(_("Could not resolve HEAD commit\n"));
 362
 363         head_commit = lookup_commit(head_sha1);
 364
 365         /*
 366          * If head_commit is NULL, check_commit, called from
 367          * lookup_commit, would have indicated that head_commit is not
 368          * a commit object already.  parse_commit() will return failure
 369          * without further complaints in such a case.  Otherwise, if
 370          * the commit is invalid, parse_commit() will complain.  So
 371          * there is nothing for us to say here.  Just return failure.
 372          */
 373         if (parse_commit(head_commit))
 374                 return -1;
 375
 376         if (!active_cache_tree)
 377                 active_cache_tree = cache_tree();
 378
 379         if (!cache_tree_fully_valid(active_cache_tree))
 380                 if (cache_tree_update(active_cache_tree,
 381                                       (const struct cache_entry * const *)active_cache,
 382                                       active_nr, 0))
 383                         return error(_("Unable to update cache tree\n"));
 384
 385         return !hashcmp(active_cache_tree->sha1, head_commit->tree->object.sha1);
 386 }
 387
 388 /*
 389  * If we are cherry-pick, and if the merge did not result in
 390  * hand-editing, we will hit this commit and inherit the original
 391  * author date and name.
 392  * If we are revert, or if our cherry-pick results in a hand merge,
 393  * we had better say that the current user is responsible for that.
 394  */
 395 static int run_git_commit(const char *defmsg, struct replay_opts *opts,
 396                           int allow_empty)
 397 {
 398         struct argv_array array;
 399         int rc;
 400
 401         argv_array_init(&array);
 402         argv_array_push(&array, "commit");
 403         argv_array_push(&array, "-n");
 404
 405         if (opts->signoff)
 406                 argv_array_push(&array, "-s");
 407         if (!opts->edit) {
 408                 argv_array_push(&array, "-F");
 409                 argv_array_push(&array, defmsg);
 410         }
 411
 412         if (allow_empty)
 413                 argv_array_push(&array, "--allow-empty");
 414
 415         if (opts->allow_empty_message)
 416                 argv_array_push(&array, "--allow-empty-message");
 417
 418         rc = run_command_v_opt(array.argv, RUN_GIT_CMD);
 419         argv_array_clear(&array);
 420         return rc;
 421 }
 422
 423 static int is_original_commit_empty(struct commit *commit)
 424 {
 425         const unsigned char *ptree_sha1;
 426
 427         if (parse_commit(commit))
 428                 return error(_("Could not parse commit %s\n"),
 429                              sha1_to_hex(commit->object.sha1));
 430         if (commit->parents) {
 431                 struct commit *parent = commit->parents->item;
 432                 if (parse_commit(parent))
 433                         return error(_("Could not parse parent commit %s\n"),
 434                                 sha1_to_hex(parent->object.sha1));
 435                 ptree_sha1 = parent->tree->object.sha1;
 436         } else {
 437                 ptree_sha1 = EMPTY_TREE_SHA1_BIN; /* commit is root */
 438         }
 439
 440         return !hashcmp(ptree_sha1, commit->tree->object.sha1);
 441 }
 442
 443 /*
 444  * Do we run "git commit" with "--allow-empty"?
 445  */
 446 static int allow_empty(struct replay_opts *opts, struct commit *commit)
 447 {
 448         int index_unchanged, empty_commit;
 449
 450         /*
 451          * Three cases:
 452          *
 453          * (1) we do not allow empty at all and error out.
 454          *
 455          * (2) we allow ones that were initially empty, but
 456          * forbid the ones that become empty;
 457          *
 458          * (3) we allow both.
 459          */
 460         if (!opts->allow_empty)
 461                 return 0; /* let "git commit" barf as necessary */
 462
 463         index_unchanged = is_index_unchanged();
 464         if (index_unchanged < 0)
 465                 return index_unchanged;
 466         if (!index_unchanged)
 467                 return 0; /* we do not have to say --allow-empty */
 468
 469         if (opts->keep_redundant_commits)
 470                 return 1;
 471
 472         empty_commit = is_original_commit_empty(commit);
 473         if (empty_commit < 0)
 474                 return empty_commit;
 475         if (!empty_commit)
 476                 return 0;
 477         else
 478                 return 1;
 479 }
 480
 481 static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
 482 {
 483         unsigned char head[20];
 484         struct commit *base, *next, *parent;
 485         const char *base_label, *next_label;
 486         struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
 487         char *defmsg = NULL;
 488         struct strbuf msgbuf = STRBUF_INIT;
 489         int res, unborn = 0, allow;
 490
 491         if (opts->no_commit) {
 492                 /*
 493                  * We do not intend to commit immediately.  We just want to
 494                  * merge the differences in, so let's compute the tree
 495                  * that represents the "current" state for merge-recursive
 496                  * to work on.
 497                  */
 498                 if (write_cache_as_tree(head, 0, NULL))
 499                         die (_("Your index file is unmerged."));
 500         } else {
 501                 unborn = get_sha1("HEAD", head);
 502                 if (unborn)
 503                         hashcpy(head, EMPTY_TREE_SHA1_BIN);
 504                 if (index_differs_from(unborn ? EMPTY_TREE_SHA1_HEX : "HEAD", 0))
 505                         return error_dirty_index(opts);
 506         }
 507         discard_cache();
 508
 509         if (!commit->parents) {
 510                 parent = NULL;
 511         }
 512         else if (commit->parents->next) {
 513                 /* Reverting or cherry-picking a merge commit */
 514                 int cnt;
 515                 struct commit_list *p;
 516
 517                 if (!opts->mainline)
 518                         return error(_("Commit %s is a merge but no -m option was given."),
 519                                 sha1_to_hex(commit->object.sha1));
 520
 521                 for (cnt = 1, p = commit->parents;
 522                      cnt != opts->mainline && p;
 523                      cnt++)
 524                         p = p->next;
 525                 if (cnt != opts->mainline || !p)
 526                         return error(_("Commit %s does not have parent %d"),
 527                                 sha1_to_hex(commit->object.sha1), opts->mainline);
 528                 parent = p->item;
 529         } else if (0 < opts->mainline)
 530                 return error(_("Mainline was specified but commit %s is not a merge."),
 531                         sha1_to_hex(commit->object.sha1));
 532         else
 533                 parent = commit->parents->item;
 534
 535         if (opts->allow_ff &&
 536             ((parent && !hashcmp(parent->object.sha1, head)) ||
 537              (!parent && unborn)))
 538                 return fast_forward_to(commit->object.sha1, head, unborn, opts);
 539
 540         if (parent && parse_commit(parent) < 0)
 541                 /* TRANSLATORS: The first %s will be "revert" or
 542                    "cherry-pick", the second %s a SHA1 */
 543                 return error(_("%s: cannot parse parent commit %s"),
 544                         action_name(opts), sha1_to_hex(parent->object.sha1));
 545
 546         if (get_message(commit, &msg) != 0)
 547                 return error(_("Cannot get commit message for %s"),
 548                         sha1_to_hex(commit->object.sha1));
 549
 550         /*
 551          * "commit" is an existing commit.  We would want to apply
 552          * the difference it introduces since its first parent "prev"
 553          * on top of the current HEAD if we are cherry-pick.  Or the
 554          * reverse of it if we are revert.
 555          */
 556
 557         defmsg = git_pathdup("MERGE_MSG");
 558
 559         if (opts->action == REPLAY_REVERT) {
 560                 base = commit;
 561                 base_label = msg.label;
 562                 next = parent;
 563                 next_label = msg.parent_label;
 564                 strbuf_addstr(&msgbuf, "Revert \"");
 565                 strbuf_addstr(&msgbuf, msg.subject);
 566                 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
 567                 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 568
 569                 if (commit->parents && commit->parents->next) {
 570                         strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
 571                         strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
 572                 }
 573                 strbuf_addstr(&msgbuf, ".\n");
 574         } else {
 575                 const char *p;
 576
 577                 base = parent;
 578                 base_label = msg.parent_label;
 579                 next = commit;
 580                 next_label = msg.label;
 581
 582                 /*
 583                  * Append the commit log message to msgbuf; it starts
 584                  * after the tree, parent, author, committer
 585                  * information followed by "\n\n".
 586                  */
 587                 p = strstr(msg.message, "\n\n");
 588                 if (p) {
 589                         p += 2;
 590                         strbuf_addstr(&msgbuf, p);
 591                 }
 592
 593                 if (opts->record_origin) {
 594                         if (!has_conforming_footer(&msgbuf, NULL, 0))
 595                                 strbuf_addch(&msgbuf, '\n');
 596                         strbuf_addstr(&msgbuf, cherry_picked_prefix);
 597                         strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 598                         strbuf_addstr(&msgbuf, ")\n");
 599                 }
 600         }
 601
 602         if (!opts->strategy || !strcmp(opts->strategy, "recursive") || opts->action == REPLAY_REVERT) {
 603                 res = do_recursive_merge(base, next, base_label, next_label,
 604                                          head, &msgbuf, opts);
 605                 write_message(&msgbuf, defmsg);
 606         } else {
 607                 struct commit_list *common = NULL;
 608                 struct commit_list *remotes = NULL;
 609
 610                 write_message(&msgbuf, defmsg);
 611
 612                 commit_list_insert(base, &common);
 613                 commit_list_insert(next, &remotes);
 614                 res = try_merge_command(opts->strategy, opts->xopts_nr, opts->xopts,
 615                                         common, sha1_to_hex(head), remotes);
 616                 free_commit_list(common);
 617                 free_commit_list(remotes);
 618         }
 619
 620         /*
 621          * If the merge was clean or if it failed due to conflict, we write
 622          * CHERRY_PICK_HEAD for the subsequent invocation of commit to use.
 623          * However, if the merge did not even start, then we don't want to
 624          * write it at all.
 625          */
 626         if (opts->action == REPLAY_PICK && !opts->no_commit && (res == 0 || res == 1))
 627                 write_cherry_pick_head(commit, "CHERRY_PICK_HEAD");
 628         if (opts->action == REPLAY_REVERT && ((opts->no_commit && res == 0) || res == 1))
 629                 write_cherry_pick_head(commit, "REVERT_HEAD");
 630
 631         if (res) {
 632                 error(opts->action == REPLAY_REVERT
 633                       ? _("could not revert %s... %s")
 634                       : _("could not apply %s... %s"),
 635                       find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV),
 636                       msg.subject);
 637                 print_advice(res == 1, opts);
 638                 rerere(opts->allow_rerere_auto);
 639                 goto leave;
 640         }
 641
 642         allow = allow_empty(opts, commit);
 643         if (allow < 0) {
 644                 res = allow;
 645                 goto leave;
 646         }
 647         if (!opts->no_commit)
 648                 res = run_git_commit(defmsg, opts, allow);
 649
 650 leave:
 651         free_message(&msg);
 652         free(defmsg);
 653
 654         return res;
 655 }
 656
 657 static void prepare_revs(struct replay_opts *opts)
 658 {
 659         /*
 660          * picking (but not reverting) ranges (but not individual revisions)
 661          * should be done in reverse
 662          */
 663         if (opts->action == REPLAY_PICK && !opts->revs->no_walk)
 664                 opts->revs->reverse ^= 1;
 665
 666         if (prepare_revision_walk(opts->revs))
 667                 die(_("revision walk setup failed"));
 668
 669         if (!opts->revs->commits)
 670                 die(_("empty commit set passed"));
 671 }
 672
 673 static void read_and_refresh_cache(struct replay_opts *opts)
 674 {
 675         static struct lock_file index_lock;
 676         int index_fd = hold_locked_index(&index_lock, 0);
 677         if (read_index_preload(&the_index, NULL) < 0)
 678                 die(_("git %s: failed to read the index"), action_name(opts));
 679         refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
 680         if (the_index.cache_changed) {
 681                 if (write_index(&the_index, index_fd) ||
 682                     commit_locked_index(&index_lock))
 683                         die(_("git %s: failed to refresh the index"), action_name(opts));
 684         }
 685         rollback_lock_file(&index_lock);
 686 }
 687
 688 static int format_todo(struct strbuf *buf, struct commit_list *todo_list,
 689                 struct replay_opts *opts)
 690 {
 691         struct commit_list *cur = NULL;
 692         const char *sha1_abbrev = NULL;
 693         const char *action_str = opts->action == REPLAY_REVERT ? "revert" : "pick";
 694         const char *subject;
 695         int subject_len;
 696
 697         for (cur = todo_list; cur; cur = cur->next) {
 698                 sha1_abbrev = find_unique_abbrev(cur->item->object.sha1, DEFAULT_ABBREV);
 699                 subject_len = find_commit_subject(cur->item->buffer, &subject);
 700                 strbuf_addf(buf, "%s %s %.*s\n", action_str, sha1_abbrev,
 701                         subject_len, subject);
 702         }
 703         return 0;
 704 }
 705
 706 static struct commit *parse_insn_line(char *bol, char *eol, struct replay_opts *opts)
 707 {
 708         unsigned char commit_sha1[20];
 709         enum replay_action action;
 710         char *end_of_object_name;
 711         int saved, status, padding;
 712
 713         if (!prefixcmp(bol, "pick")) {
 714                 action = REPLAY_PICK;
 715                 bol += strlen("pick");
 716         } else if (!prefixcmp(bol, "revert")) {
 717                 action = REPLAY_REVERT;
 718                 bol += strlen("revert");
 719         } else
 720                 return NULL;
 721
 722         /* Eat up extra spaces/ tabs before object name */
 723         padding = strspn(bol, " \t");
 724         if (!padding)
 725                 return NULL;
 726         bol += padding;
 727
 728         end_of_object_name = bol + strcspn(bol, " \t\n");
 729         saved = *end_of_object_name;
 730         *end_of_object_name = '\0';
 731         status = get_sha1(bol, commit_sha1);
 732         *end_of_object_name = saved;
 733
 734         /*
 735          * Verify that the action matches up with the one in
 736          * opts; we don't support arbitrary instructions
 737          */
 738         if (action != opts->action) {
 739                 const char *action_str;
 740                 action_str = action == REPLAY_REVERT ? "revert" : "cherry-pick";
 741                 error(_("Cannot %s during a %s"), action_str, action_name(opts));
 742                 return NULL;
 743         }
 744
 745         if (status < 0)
 746                 return NULL;
 747
 748         return lookup_commit_reference(commit_sha1);
 749 }
 750
 751 static int parse_insn_buffer(char *buf, struct commit_list **todo_list,
 752                         struct replay_opts *opts)
 753 {
 754         struct commit_list **next = todo_list;
 755         struct commit *commit;
 756         char *p = buf;
 757         int i;
 758
 759         for (i = 1; *p; i++) {
 760                 char *eol = strchrnul(p, '\n');
 761                 commit = parse_insn_line(p, eol, opts);
 762                 if (!commit)
 763                         return error(_("Could not parse line %d."), i);
 764                 next = commit_list_append(commit, next);
 765                 p = *eol ? eol + 1 : eol;
 766         }
 767         if (!*todo_list)
 768                 return error(_("No commits parsed."));
 769         return 0;
 770 }
 771
 772 static void read_populate_todo(struct commit_list **todo_list,
 773                         struct replay_opts *opts)
 774 {
 775         const char *todo_file = git_path(SEQ_TODO_FILE);
 776         struct strbuf buf = STRBUF_INIT;
 777         int fd, res;
 778
 779         fd = open(todo_file, O_RDONLY);
 780         if (fd < 0)
 781                 die_errno(_("Could not open %s"), todo_file);
 782         if (strbuf_read(&buf, fd, 0) < 0) {
 783                 close(fd);
 784                 strbuf_release(&buf);
 785                 die(_("Could not read %s."), todo_file);
 786         }
 787         close(fd);
 788
 789         res = parse_insn_buffer(buf.buf, todo_list, opts);
 790         strbuf_release(&buf);
 791         if (res)
 792                 die(_("Unusable instruction sheet: %s"), todo_file);
 793 }
 794
 795 static int populate_opts_cb(const char *key, const char *value, void *data)
 796 {
 797         struct replay_opts *opts = data;
 798         int error_flag = 1;
 799
 800         if (!value)
 801                 error_flag = 0;
 802         else if (!strcmp(key, "options.no-commit"))
 803                 opts->no_commit = git_config_bool_or_int(key, value, &error_flag);
 804         else if (!strcmp(key, "options.edit"))
 805                 opts->edit = git_config_bool_or_int(key, value, &error_flag);
 806         else if (!strcmp(key, "options.signoff"))
 807                 opts->signoff = git_config_bool_or_int(key, value, &error_flag);
 808         else if (!strcmp(key, "options.record-origin"))
 809                 opts->record_origin = git_config_bool_or_int(key, value, &error_flag);
 810         else if (!strcmp(key, "options.allow-ff"))
 811                 opts->allow_ff = git_config_bool_or_int(key, value, &error_flag);
 812         else if (!strcmp(key, "options.mainline"))
 813                 opts->mainline = git_config_int(key, value);
 814         else if (!strcmp(key, "options.strategy"))
 815                 git_config_string(&opts->strategy, key, value);
 816         else if (!strcmp(key, "options.strategy-option")) {
 817                 ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
 818                 opts->xopts[opts->xopts_nr++] = xstrdup(value);
 819         } else
 820                 return error(_("Invalid key: %s"), key);
 821
 822         if (!error_flag)
 823                 return error(_("Invalid value for %s: %s"), key, value);
 824
 825         return 0;
 826 }
 827
 828 static void read_populate_opts(struct replay_opts **opts_ptr)
 829 {
 830         const char *opts_file = git_path(SEQ_OPTS_FILE);
 831
 832         if (!file_exists(opts_file))
 833                 return;
 834         if (git_config_from_file(populate_opts_cb, opts_file, *opts_ptr) < 0)
 835                 die(_("Malformed options sheet: %s"), opts_file);
 836 }
 837
 838 static void walk_revs_populate_todo(struct commit_list **todo_list,
 839                                 struct replay_opts *opts)
 840 {
 841         struct commit *commit;
 842         struct commit_list **next;
 843
 844         prepare_revs(opts);
 845
 846         next = todo_list;
 847         while ((commit = get_revision(opts->revs)))
 848                 next = commit_list_append(commit, next);
 849 }
 850
 851 static int create_seq_dir(void)
 852 {
 853         const char *seq_dir = git_path(SEQ_DIR);
 854
 855         if (file_exists(seq_dir)) {
 856                 error(_("a cherry-pick or revert is already in progress"));
 857                 advise(_("try \"git cherry-pick (--continue | --quit | --abort)\""));
 858                 return -1;
 859         }
 860         else if (mkdir(seq_dir, 0777) < 0)
 861                 die_errno(_("Could not create sequencer directory %s"), seq_dir);
 862         return 0;
 863 }
 864
 865 static void save_head(const char *head)
 866 {
 867         const char *head_file = git_path(SEQ_HEAD_FILE);
 868         static struct lock_file head_lock;
 869         struct strbuf buf = STRBUF_INIT;
 870         int fd;
 871
 872         fd = hold_lock_file_for_update(&head_lock, head_file, LOCK_DIE_ON_ERROR);
 873         strbuf_addf(&buf, "%s\n", head);
 874         if (write_in_full(fd, buf.buf, buf.len) < 0)
 875                 die_errno(_("Could not write to %s"), head_file);
 876         if (commit_lock_file(&head_lock) < 0)
 877                 die(_("Error wrapping up %s."), head_file);
 878 }
 879
 880 static int reset_for_rollback(const unsigned char *sha1)
 881 {
 882         const char *argv[4];    /* reset --merge <arg> + NULL */
 883         argv[0] = "reset";
 884         argv[1] = "--merge";
 885         argv[2] = sha1_to_hex(sha1);
 886         argv[3] = NULL;
 887         return run_command_v_opt(argv, RUN_GIT_CMD);
 888 }
 889
 890 static int rollback_single_pick(void)
 891 {
 892         unsigned char head_sha1[20];
 893
 894         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
 895             !file_exists(git_path("REVERT_HEAD")))
 896                 return error(_("no cherry-pick or revert in progress"));
 897         if (read_ref_full("HEAD", head_sha1, 0, NULL))
 898                 return error(_("cannot resolve HEAD"));
 899         if (is_null_sha1(head_sha1))
 900                 return error(_("cannot abort from a branch yet to be born"));
 901         return reset_for_rollback(head_sha1);
 902 }
 903
 904 static int sequencer_rollback(struct replay_opts *opts)
 905 {
 906         const char *filename;
 907         FILE *f;
 908         unsigned char sha1[20];
 909         struct strbuf buf = STRBUF_INIT;
 910
 911         filename = git_path(SEQ_HEAD_FILE);
 912         f = fopen(filename, "r");
 913         if (!f && errno == ENOENT) {
 914                 /*
 915                  * There is no multiple-cherry-pick in progress.
 916                  * If CHERRY_PICK_HEAD or REVERT_HEAD indicates
 917                  * a single-cherry-pick in progress, abort that.
 918                  */
 919                 return rollback_single_pick();
 920         }
 921         if (!f)
 922                 return error(_("cannot open %s: %s"), filename,
 923                                                 strerror(errno));
 924         if (strbuf_getline(&buf, f, '\n')) {
 925                 error(_("cannot read %s: %s"), filename, ferror(f) ?
 926                         strerror(errno) : _("unexpected end of file"));
 927                 fclose(f);
 928                 goto fail;
 929         }
 930         fclose(f);
 931         if (get_sha1_hex(buf.buf, sha1) || buf.buf[40] != '\0') {
 932                 error(_("stored pre-cherry-pick HEAD file '%s' is corrupt"),
 933                         filename);
 934                 goto fail;
 935         }
 936         if (reset_for_rollback(sha1))
 937                 goto fail;
 938         remove_sequencer_state();
 939         strbuf_release(&buf);
 940         return 0;
 941 fail:
 942         strbuf_release(&buf);
 943         return -1;
 944 }
 945
 946 static void save_todo(struct commit_list *todo_list, struct replay_opts *opts)
 947 {
 948         const char *todo_file = git_path(SEQ_TODO_FILE);
 949         static struct lock_file todo_lock;
 950         struct strbuf buf = STRBUF_INIT;
 951         int fd;
 952
 953         fd = hold_lock_file_for_update(&todo_lock, todo_file, LOCK_DIE_ON_ERROR);
 954         if (format_todo(&buf, todo_list, opts) < 0)
 955                 die(_("Could not format %s."), todo_file);
 956         if (write_in_full(fd, buf.buf, buf.len) < 0) {
 957                 strbuf_release(&buf);
 958                 die_errno(_("Could not write to %s"), todo_file);
 959         }
 960         if (commit_lock_file(&todo_lock) < 0) {
 961                 strbuf_release(&buf);
 962                 die(_("Error wrapping up %s."), todo_file);
 963         }
 964         strbuf_release(&buf);
 965 }
 966
 967 static void save_opts(struct replay_opts *opts)
 968 {
 969         const char *opts_file = git_path(SEQ_OPTS_FILE);
 970
 971         if (opts->no_commit)
 972                 git_config_set_in_file(opts_file, "options.no-commit", "true");
 973         if (opts->edit)
 974                 git_config_set_in_file(opts_file, "options.edit", "true");
 975         if (opts->signoff)
 976                 git_config_set_in_file(opts_file, "options.signoff", "true");
 977         if (opts->record_origin)
 978                 git_config_set_in_file(opts_file, "options.record-origin", "true");
 979         if (opts->allow_ff)
 980                 git_config_set_in_file(opts_file, "options.allow-ff", "true");
 981         if (opts->mainline) {
 982                 struct strbuf buf = STRBUF_INIT;
 983                 strbuf_addf(&buf, "%d", opts->mainline);
 984                 git_config_set_in_file(opts_file, "options.mainline", buf.buf);
 985                 strbuf_release(&buf);
 986         }
 987         if (opts->strategy)
 988                 git_config_set_in_file(opts_file, "options.strategy", opts->strategy);
 989         if (opts->xopts) {
 990                 int i;
 991                 for (i = 0; i < opts->xopts_nr; i++)
 992                         git_config_set_multivar_in_file(opts_file,
 993                                                         "options.strategy-option",
 994                                                         opts->xopts[i], "^$", 0);
 995         }
 996 }
 997
 998 static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
 999 {
1000         struct commit_list *cur;
1001         int res;
1002
1003         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
1004         if (opts->allow_ff)
1005                 assert(!(opts->signoff || opts->no_commit ||
1006                                 opts->record_origin || opts->edit));
1007         read_and_refresh_cache(opts);
1008
1009         for (cur = todo_list; cur; cur = cur->next) {
1010                 save_todo(cur, opts);
1011                 res = do_pick_commit(cur->item, opts);
1012                 if (res)
1013                         return res;
1014         }
1015
1016         /*
1017          * Sequence of picks finished successfully; cleanup by
1018          * removing the .git/sequencer directory
1019          */
1020         remove_sequencer_state();
1021         return 0;
1022 }
1023
1024 static int continue_single_pick(void)
1025 {
1026         const char *argv[] = { "commit", NULL };
1027
1028         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
1029             !file_exists(git_path("REVERT_HEAD")))
1030                 return error(_("no cherry-pick or revert in progress"));
1031         return run_command_v_opt(argv, RUN_GIT_CMD);
1032 }
1033
1034 static int sequencer_continue(struct replay_opts *opts)
1035 {
1036         struct commit_list *todo_list = NULL;
1037
1038         if (!file_exists(git_path(SEQ_TODO_FILE)))
1039                 return continue_single_pick();
1040         read_populate_opts(&opts);
1041         read_populate_todo(&todo_list, opts);
1042
1043         /* Verify that the conflict has been resolved */
1044         if (file_exists(git_path("CHERRY_PICK_HEAD")) ||
1045             file_exists(git_path("REVERT_HEAD"))) {
1046                 int ret = continue_single_pick();
1047                 if (ret)
1048                         return ret;
1049         }
1050         if (index_differs_from("HEAD", 0))
1051                 return error_dirty_index(opts);
1052         todo_list = todo_list->next;
1053         return pick_commits(todo_list, opts);
1054 }
1055
1056 static int single_pick(struct commit *cmit, struct replay_opts *opts)
1057 {
1058         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
1059         return do_pick_commit(cmit, opts);
1060 }
1061
1062 int sequencer_pick_revisions(struct replay_opts *opts)
1063 {
1064         struct commit_list *todo_list = NULL;
1065         unsigned char sha1[20];
1066         int i;
1067
1068         if (opts->subcommand == REPLAY_NONE)
1069                 assert(opts->revs);
1070
1071         read_and_refresh_cache(opts);
1072
1073         /*
1074          * Decide what to do depending on the arguments; a fresh
1075          * cherry-pick should be handled differently from an existing
1076          * one that is being continued
1077          */
1078         if (opts->subcommand == REPLAY_REMOVE_STATE) {
1079                 remove_sequencer_state();
1080                 return 0;
1081         }
1082         if (opts->subcommand == REPLAY_ROLLBACK)
1083                 return sequencer_rollback(opts);
1084         if (opts->subcommand == REPLAY_CONTINUE)
1085                 return sequencer_continue(opts);
1086
1087         for (i = 0; i < opts->revs->pending.nr; i++) {
1088                 unsigned char sha1[20];
1089                 const char *name = opts->revs->pending.objects[i].name;
1090
1091                 /* This happens when using --stdin. */
1092                 if (!strlen(name))
1093                         continue;
1094
1095                 if (!get_sha1(name, sha1)) {
1096                         if (!lookup_commit_reference_gently(sha1, 1)) {
1097                                 enum object_type type = sha1_object_info(sha1, NULL);
1098                                 die(_("%s: can't cherry-pick a %s"), name, typename(type));
1099                         }
1100                 } else
1101                         die(_("%s: bad revision"), name);
1102         }
1103
1104         /*
1105          * If we were called as "git cherry-pick <commit>", just
1106          * cherry-pick/revert it, set CHERRY_PICK_HEAD /
1107          * REVERT_HEAD, and don't touch the sequencer state.
1108          * This means it is possible to cherry-pick in the middle
1109          * of a cherry-pick sequence.
1110          */
1111         if (opts->revs->cmdline.nr == 1 &&
1112             opts->revs->cmdline.rev->whence == REV_CMD_REV &&
1113             opts->revs->no_walk &&
1114             !opts->revs->cmdline.rev->flags) {
1115                 struct commit *cmit;
1116                 if (prepare_revision_walk(opts->revs))
1117                         die(_("revision walk setup failed"));
1118                 cmit = get_revision(opts->revs);
1119                 if (!cmit || get_revision(opts->revs))
1120                         die("BUG: expected exactly one commit from walk");
1121                 return single_pick(cmit, opts);
1122         }
1123
1124         /*
1125          * Start a new cherry-pick/ revert sequence; but
1126          * first, make sure that an existing one isn't in
1127          * progress
1128          */
1129
1130         walk_revs_populate_todo(&todo_list, opts);
1131         if (create_seq_dir() < 0)
1132                 return -1;
1133         if (get_sha1("HEAD", sha1)) {
1134                 if (opts->action == REPLAY_REVERT)
1135                         return error(_("Can't revert as initial commit"));
1136                 return error(_("Can't cherry-pick into empty head"));
1137         }
1138         save_head(sha1_to_hex(sha1));
1139         save_opts(opts);
1140         return pick_commits(todo_list, opts);
1141 }
1142
1143 void append_signoff(struct strbuf *msgbuf, int ignore_footer, unsigned flag)
1144 {
1145         unsigned no_dup_sob = flag & APPEND_SIGNOFF_DEDUP;
1146         struct strbuf sob = STRBUF_INIT;
1147         int has_footer;
1148
1149         strbuf_addstr(&sob, sign_off_header);
1150         strbuf_addstr(&sob, fmt_name(getenv("GIT_COMMITTER_NAME"),
1151                                 getenv("GIT_COMMITTER_EMAIL")));
1152         strbuf_addch(&sob, '\n');
1153
1154         /*
1155          * If the whole message buffer is equal to the sob, pretend that we
1156          * found a conforming footer with a matching sob
1157          */
1158         if (msgbuf->len - ignore_footer == sob.len &&
1159             !strncmp(msgbuf->buf, sob.buf, sob.len))
1160                 has_footer = 3;
1161         else
1162                 has_footer = has_conforming_footer(msgbuf, &sob, ignore_footer);
1163
1164         if (!has_footer) {
1165                 const char *append_newlines = NULL;
1166                 size_t len = msgbuf->len - ignore_footer;
1167
1168                 if (!len) {
1169                         /*
1170                          * The buffer is completely empty.  Leave foom for
1171                          * the title and body to be filled in by the user.
1172                          */
1173                         append_newlines = "\n\n";
1174                 } else if (msgbuf->buf[len - 1] != '\n') {
1175                         /*
1176                          * Incomplete line.  Complete the line and add a
1177                          * blank one so that there is an empty line between
1178                          * the message body and the sob.
1179                          */
1180                         append_newlines = "\n\n";
1181                 } else if (len == 1) {
1182                         /*
1183                          * Buffer contains a single newline.  Add another
1184                          * so that we leave room for the title and body.
1185                          */
1186                         append_newlines = "\n";
1187                 } else if (msgbuf->buf[len - 2] != '\n') {
1188                         /*
1189                          * Buffer ends with a single newline.  Add another
1190                          * so that there is an empty line between the message
1191                          * body and the sob.
1192                          */
1193                         append_newlines = "\n";
1194                 } /* else, the buffer already ends with two newlines. */
1195
1196                 if (append_newlines)
1197                         strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0,
1198                                 append_newlines, strlen(append_newlines));
1199         }
1200
1201         if (has_footer != 3 && (!no_dup_sob || has_footer != 2))
1202                 strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0,
1203                                 sob.buf, sob.len);
1204
1205         strbuf_release(&sob);
1206 }