git.oblomov.eu Git - git/blob - sequencer.c

   1 #include "cache.h"
   2 #include "lockfile.h"
   3 #include "sequencer.h"
   4 #include "dir.h"
   5 #include "object.h"
   6 #include "commit.h"
   7 #include "tag.h"
   8 #include "run-command.h"
   9 #include "exec_cmd.h"
  10 #include "utf8.h"
  11 #include "cache-tree.h"
  12 #include "diff.h"
  13 #include "revision.h"
  14 #include "rerere.h"
  15 #include "merge-recursive.h"
  16 #include "refs.h"
  17 #include "argv-array.h"
  18
  19 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
  20
  21 const char sign_off_header[] = "Signed-off-by: ";
  22 static const char cherry_picked_prefix[] = "(cherry picked from commit ";
  23
  24 static GIT_PATH_FUNC(git_path_todo_file, SEQ_TODO_FILE)
  25 static GIT_PATH_FUNC(git_path_opts_file, SEQ_OPTS_FILE)
  26 static GIT_PATH_FUNC(git_path_seq_dir, SEQ_DIR)
  27 static GIT_PATH_FUNC(git_path_head_file, SEQ_HEAD_FILE)
  28
  29 static int is_rfc2822_line(const char *buf, int len)
  30 {
  31         int i;
  32
  33         for (i = 0; i < len; i++) {
  34                 int ch = buf[i];
  35                 if (ch == ':')
  36                         return 1;
  37                 if (!isalnum(ch) && ch != '-')
  38                         break;
  39         }
  40
  41         return 0;
  42 }
  43
  44 static int is_cherry_picked_from_line(const char *buf, int len)
  45 {
  46         /*
  47          * We only care that it looks roughly like (cherry picked from ...)
  48          */
  49         return len > strlen(cherry_picked_prefix) + 1 &&
  50                 starts_with(buf, cherry_picked_prefix) && buf[len - 1] == ')';
  51 }
  52
  53 /*
  54  * Returns 0 for non-conforming footer
  55  * Returns 1 for conforming footer
  56  * Returns 2 when sob exists within conforming footer
  57  * Returns 3 when sob exists within conforming footer as last entry
  58  */
  59 static int has_conforming_footer(struct strbuf *sb, struct strbuf *sob,
  60         int ignore_footer)
  61 {
  62         char prev;
  63         int i, k;
  64         int len = sb->len - ignore_footer;
  65         const char *buf = sb->buf;
  66         int found_sob = 0;
  67
  68         /* footer must end with newline */
  69         if (!len || buf[len - 1] != '\n')
  70                 return 0;
  71
  72         prev = '\0';
  73         for (i = len - 1; i > 0; i--) {
  74                 char ch = buf[i];
  75                 if (prev == '\n' && ch == '\n') /* paragraph break */
  76                         break;
  77                 prev = ch;
  78         }
  79
  80         /* require at least one blank line */
  81         if (prev != '\n' || buf[i] != '\n')
  82                 return 0;
  83
  84         /* advance to start of last paragraph */
  85         while (i < len - 1 && buf[i] == '\n')
  86                 i++;
  87
  88         for (; i < len; i = k) {
  89                 int found_rfc2822;
  90
  91                 for (k = i; k < len && buf[k] != '\n'; k++)
  92                         ; /* do nothing */
  93                 k++;
  94
  95                 found_rfc2822 = is_rfc2822_line(buf + i, k - i - 1);
  96                 if (found_rfc2822 && sob &&
  97                     !strncmp(buf + i, sob->buf, sob->len))
  98                         found_sob = k;
  99
 100                 if (!(found_rfc2822 ||
 101                       is_cherry_picked_from_line(buf + i, k - i - 1)))
 102                         return 0;
 103         }
 104         if (found_sob == i)
 105                 return 3;
 106         if (found_sob)
 107                 return 2;
 108         return 1;
 109 }
 110
 111 static void remove_sequencer_state(void)
 112 {
 113         struct strbuf seq_dir = STRBUF_INIT;
 114
 115         strbuf_addstr(&seq_dir, git_path(SEQ_DIR));
 116         remove_dir_recursively(&seq_dir, 0);
 117         strbuf_release(&seq_dir);
 118 }
 119
 120 static const char *action_name(const struct replay_opts *opts)
 121 {
 122         return opts->action == REPLAY_REVERT ? "revert" : "cherry-pick";
 123 }
 124
 125 struct commit_message {
 126         char *parent_label;
 127         char *label;
 128         char *subject;
 129         const char *message;
 130 };
 131
 132 static int get_message(struct commit *commit, struct commit_message *out)
 133 {
 134         const char *abbrev, *subject;
 135         int subject_len;
 136
 137         out->message = logmsg_reencode(commit, NULL, get_commit_output_encoding());
 138         abbrev = find_unique_abbrev(commit->object.oid.hash, DEFAULT_ABBREV);
 139
 140         subject_len = find_commit_subject(out->message, &subject);
 141
 142         out->subject = xmemdupz(subject, subject_len);
 143         out->label = xstrfmt("%s... %s", abbrev, out->subject);
 144         out->parent_label = xstrfmt("parent of %s", out->label);
 145
 146         return 0;
 147 }
 148
 149 static void free_message(struct commit *commit, struct commit_message *msg)
 150 {
 151         free(msg->parent_label);
 152         free(msg->label);
 153         free(msg->subject);
 154         unuse_commit_buffer(commit, msg->message);
 155 }
 156
 157 static void print_advice(int show_hint, struct replay_opts *opts)
 158 {
 159         char *msg = getenv("GIT_CHERRY_PICK_HELP");
 160
 161         if (msg) {
 162                 fprintf(stderr, "%s\n", msg);
 163                 /*
 164                  * A conflict has occurred but the porcelain
 165                  * (typically rebase --interactive) wants to take care
 166                  * of the commit itself so remove CHERRY_PICK_HEAD
 167                  */
 168                 unlink(git_path_cherry_pick_head());
 169                 return;
 170         }
 171
 172         if (show_hint) {
 173                 if (opts->no_commit)
 174                         advise(_("after resolving the conflicts, mark the corrected paths\n"
 175                                  "with 'git add <paths>' or 'git rm <paths>'"));
 176                 else
 177                         advise(_("after resolving the conflicts, mark the corrected paths\n"
 178                                  "with 'git add <paths>' or 'git rm <paths>'\n"
 179                                  "and commit the result with 'git commit'"));
 180         }
 181 }
 182
 183 static int write_message(struct strbuf *msgbuf, const char *filename)
 184 {
 185         static struct lock_file msg_file;
 186
 187         int msg_fd = hold_lock_file_for_update(&msg_file, filename, 0);
 188         if (msg_fd < 0)
 189                 return error_errno(_("Could not lock '%s'"), filename);
 190         if (write_in_full(msg_fd, msgbuf->buf, msgbuf->len) < 0)
 191                 return error_errno(_("Could not write to %s"), filename);
 192         strbuf_release(msgbuf);
 193         if (commit_lock_file(&msg_file) < 0)
 194                 return error(_("Error wrapping up %s."), filename);
 195
 196         return 0;
 197 }
 198
 199 static struct tree *empty_tree(void)
 200 {
 201         return lookup_tree(EMPTY_TREE_SHA1_BIN);
 202 }
 203
 204 static int error_dirty_index(struct replay_opts *opts)
 205 {
 206         if (read_cache_unmerged())
 207                 return error_resolve_conflict(action_name(opts));
 208
 209         /* Different translation strings for cherry-pick and revert */
 210         if (opts->action == REPLAY_PICK)
 211                 error(_("Your local changes would be overwritten by cherry-pick."));
 212         else
 213                 error(_("Your local changes would be overwritten by revert."));
 214
 215         if (advice_commit_before_merge)
 216                 advise(_("Commit your changes or stash them to proceed."));
 217         return -1;
 218 }
 219
 220 static int fast_forward_to(const unsigned char *to, const unsigned char *from,
 221                         int unborn, struct replay_opts *opts)
 222 {
 223         struct ref_transaction *transaction;
 224         struct strbuf sb = STRBUF_INIT;
 225         struct strbuf err = STRBUF_INIT;
 226
 227         read_cache();
 228         if (checkout_fast_forward(from, to, 1))
 229                 return -1; /* the callee should have complained already */
 230
 231         strbuf_addf(&sb, _("%s: fast-forward"), action_name(opts));
 232
 233         transaction = ref_transaction_begin(&err);
 234         if (!transaction ||
 235             ref_transaction_update(transaction, "HEAD",
 236                                    to, unborn ? null_sha1 : from,
 237                                    0, sb.buf, &err) ||
 238             ref_transaction_commit(transaction, &err)) {
 239                 ref_transaction_free(transaction);
 240                 error("%s", err.buf);
 241                 strbuf_release(&sb);
 242                 strbuf_release(&err);
 243                 return -1;
 244         }
 245
 246         strbuf_release(&sb);
 247         strbuf_release(&err);
 248         ref_transaction_free(transaction);
 249         return 0;
 250 }
 251
 252 void append_conflicts_hint(struct strbuf *msgbuf)
 253 {
 254         int i;
 255
 256         strbuf_addch(msgbuf, '\n');
 257         strbuf_commented_addf(msgbuf, "Conflicts:\n");
 258         for (i = 0; i < active_nr;) {
 259                 const struct cache_entry *ce = active_cache[i++];
 260                 if (ce_stage(ce)) {
 261                         strbuf_commented_addf(msgbuf, "\t%s\n", ce->name);
 262                         while (i < active_nr && !strcmp(ce->name,
 263                                                         active_cache[i]->name))
 264                                 i++;
 265                 }
 266         }
 267 }
 268
 269 static int do_recursive_merge(struct commit *base, struct commit *next,
 270                               const char *base_label, const char *next_label,
 271                               unsigned char *head, struct strbuf *msgbuf,
 272                               struct replay_opts *opts)
 273 {
 274         struct merge_options o;
 275         struct tree *result, *next_tree, *base_tree, *head_tree;
 276         int clean;
 277         const char **xopt;
 278         static struct lock_file index_lock;
 279
 280         hold_locked_index(&index_lock, 1);
 281
 282         read_cache();
 283
 284         init_merge_options(&o);
 285         o.ancestor = base ? base_label : "(empty tree)";
 286         o.branch1 = "HEAD";
 287         o.branch2 = next ? next_label : "(empty tree)";
 288
 289         head_tree = parse_tree_indirect(head);
 290         next_tree = next ? next->tree : empty_tree();
 291         base_tree = base ? base->tree : empty_tree();
 292
 293         for (xopt = opts->xopts; xopt != opts->xopts + opts->xopts_nr; xopt++)
 294                 parse_merge_opt(&o, *xopt);
 295
 296         clean = merge_trees(&o,
 297                             head_tree,
 298                             next_tree, base_tree, &result);
 299         strbuf_release(&o.obuf);
 300         if (clean < 0)
 301                 return clean;
 302
 303         if (active_cache_changed &&
 304             write_locked_index(&the_index, &index_lock, COMMIT_LOCK))
 305                 /* TRANSLATORS: %s will be "revert" or "cherry-pick" */
 306                 return error(_("%s: Unable to write new index file"),
 307                         action_name(opts));
 308         rollback_lock_file(&index_lock);
 309
 310         if (opts->signoff)
 311                 append_signoff(msgbuf, 0, 0);
 312
 313         if (!clean)
 314                 append_conflicts_hint(msgbuf);
 315
 316         return !clean;
 317 }
 318
 319 static int is_index_unchanged(void)
 320 {
 321         unsigned char head_sha1[20];
 322         struct commit *head_commit;
 323
 324         if (!resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, head_sha1, NULL))
 325                 return error(_("Could not resolve HEAD commit\n"));
 326
 327         head_commit = lookup_commit(head_sha1);
 328
 329         /*
 330          * If head_commit is NULL, check_commit, called from
 331          * lookup_commit, would have indicated that head_commit is not
 332          * a commit object already.  parse_commit() will return failure
 333          * without further complaints in such a case.  Otherwise, if
 334          * the commit is invalid, parse_commit() will complain.  So
 335          * there is nothing for us to say here.  Just return failure.
 336          */
 337         if (parse_commit(head_commit))
 338                 return -1;
 339
 340         if (!active_cache_tree)
 341                 active_cache_tree = cache_tree();
 342
 343         if (!cache_tree_fully_valid(active_cache_tree))
 344                 if (cache_tree_update(&the_index, 0))
 345                         return error(_("Unable to update cache tree\n"));
 346
 347         return !hashcmp(active_cache_tree->sha1, head_commit->tree->object.oid.hash);
 348 }
 349
 350 /*
 351  * If we are cherry-pick, and if the merge did not result in
 352  * hand-editing, we will hit this commit and inherit the original
 353  * author date and name.
 354  * If we are revert, or if our cherry-pick results in a hand merge,
 355  * we had better say that the current user is responsible for that.
 356  */
 357 static int run_git_commit(const char *defmsg, struct replay_opts *opts,
 358                           int allow_empty)
 359 {
 360         struct argv_array array;
 361         int rc;
 362         const char *value;
 363
 364         argv_array_init(&array);
 365         argv_array_push(&array, "commit");
 366         argv_array_push(&array, "-n");
 367
 368         if (opts->gpg_sign)
 369                 argv_array_pushf(&array, "-S%s", opts->gpg_sign);
 370         if (opts->signoff)
 371                 argv_array_push(&array, "-s");
 372         if (!opts->edit) {
 373                 argv_array_push(&array, "-F");
 374                 argv_array_push(&array, defmsg);
 375                 if (!opts->signoff &&
 376                     !opts->record_origin &&
 377                     git_config_get_value("commit.cleanup", &value))
 378                         argv_array_push(&array, "--cleanup=verbatim");
 379         }
 380
 381         if (allow_empty)
 382                 argv_array_push(&array, "--allow-empty");
 383
 384         if (opts->allow_empty_message)
 385                 argv_array_push(&array, "--allow-empty-message");
 386
 387         rc = run_command_v_opt(array.argv, RUN_GIT_CMD);
 388         argv_array_clear(&array);
 389         return rc;
 390 }
 391
 392 static int is_original_commit_empty(struct commit *commit)
 393 {
 394         const unsigned char *ptree_sha1;
 395
 396         if (parse_commit(commit))
 397                 return error(_("Could not parse commit %s\n"),
 398                              oid_to_hex(&commit->object.oid));
 399         if (commit->parents) {
 400                 struct commit *parent = commit->parents->item;
 401                 if (parse_commit(parent))
 402                         return error(_("Could not parse parent commit %s\n"),
 403                                 oid_to_hex(&parent->object.oid));
 404                 ptree_sha1 = parent->tree->object.oid.hash;
 405         } else {
 406                 ptree_sha1 = EMPTY_TREE_SHA1_BIN; /* commit is root */
 407         }
 408
 409         return !hashcmp(ptree_sha1, commit->tree->object.oid.hash);
 410 }
 411
 412 /*
 413  * Do we run "git commit" with "--allow-empty"?
 414  */
 415 static int allow_empty(struct replay_opts *opts, struct commit *commit)
 416 {
 417         int index_unchanged, empty_commit;
 418
 419         /*
 420          * Three cases:
 421          *
 422          * (1) we do not allow empty at all and error out.
 423          *
 424          * (2) we allow ones that were initially empty, but
 425          * forbid the ones that become empty;
 426          *
 427          * (3) we allow both.
 428          */
 429         if (!opts->allow_empty)
 430                 return 0; /* let "git commit" barf as necessary */
 431
 432         index_unchanged = is_index_unchanged();
 433         if (index_unchanged < 0)
 434                 return index_unchanged;
 435         if (!index_unchanged)
 436                 return 0; /* we do not have to say --allow-empty */
 437
 438         if (opts->keep_redundant_commits)
 439                 return 1;
 440
 441         empty_commit = is_original_commit_empty(commit);
 442         if (empty_commit < 0)
 443                 return empty_commit;
 444         if (!empty_commit)
 445                 return 0;
 446         else
 447                 return 1;
 448 }
 449
 450 static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
 451 {
 452         unsigned char head[20];
 453         struct commit *base, *next, *parent;
 454         const char *base_label, *next_label;
 455         struct commit_message msg = { NULL, NULL, NULL, NULL };
 456         struct strbuf msgbuf = STRBUF_INIT;
 457         int res, unborn = 0, allow;
 458
 459         if (opts->no_commit) {
 460                 /*
 461                  * We do not intend to commit immediately.  We just want to
 462                  * merge the differences in, so let's compute the tree
 463                  * that represents the "current" state for merge-recursive
 464                  * to work on.
 465                  */
 466                 if (write_cache_as_tree(head, 0, NULL))
 467                         return error(_("Your index file is unmerged."));
 468         } else {
 469                 unborn = get_sha1("HEAD", head);
 470                 if (unborn)
 471                         hashcpy(head, EMPTY_TREE_SHA1_BIN);
 472                 if (index_differs_from(unborn ? EMPTY_TREE_SHA1_HEX : "HEAD", 0))
 473                         return error_dirty_index(opts);
 474         }
 475         discard_cache();
 476
 477         if (!commit->parents) {
 478                 parent = NULL;
 479         }
 480         else if (commit->parents->next) {
 481                 /* Reverting or cherry-picking a merge commit */
 482                 int cnt;
 483                 struct commit_list *p;
 484
 485                 if (!opts->mainline)
 486                         return error(_("Commit %s is a merge but no -m option was given."),
 487                                 oid_to_hex(&commit->object.oid));
 488
 489                 for (cnt = 1, p = commit->parents;
 490                      cnt != opts->mainline && p;
 491                      cnt++)
 492                         p = p->next;
 493                 if (cnt != opts->mainline || !p)
 494                         return error(_("Commit %s does not have parent %d"),
 495                                 oid_to_hex(&commit->object.oid), opts->mainline);
 496                 parent = p->item;
 497         } else if (0 < opts->mainline)
 498                 return error(_("Mainline was specified but commit %s is not a merge."),
 499                         oid_to_hex(&commit->object.oid));
 500         else
 501                 parent = commit->parents->item;
 502
 503         if (opts->allow_ff &&
 504             ((parent && !hashcmp(parent->object.oid.hash, head)) ||
 505              (!parent && unborn)))
 506                 return fast_forward_to(commit->object.oid.hash, head, unborn, opts);
 507
 508         if (parent && parse_commit(parent) < 0)
 509                 /* TRANSLATORS: The first %s will be "revert" or
 510                    "cherry-pick", the second %s a SHA1 */
 511                 return error(_("%s: cannot parse parent commit %s"),
 512                         action_name(opts), oid_to_hex(&parent->object.oid));
 513
 514         if (get_message(commit, &msg) != 0)
 515                 return error(_("Cannot get commit message for %s"),
 516                         oid_to_hex(&commit->object.oid));
 517
 518         /*
 519          * "commit" is an existing commit.  We would want to apply
 520          * the difference it introduces since its first parent "prev"
 521          * on top of the current HEAD if we are cherry-pick.  Or the
 522          * reverse of it if we are revert.
 523          */
 524
 525         if (opts->action == REPLAY_REVERT) {
 526                 base = commit;
 527                 base_label = msg.label;
 528                 next = parent;
 529                 next_label = msg.parent_label;
 530                 strbuf_addstr(&msgbuf, "Revert \"");
 531                 strbuf_addstr(&msgbuf, msg.subject);
 532                 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
 533                 strbuf_addstr(&msgbuf, oid_to_hex(&commit->object.oid));
 534
 535                 if (commit->parents && commit->parents->next) {
 536                         strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
 537                         strbuf_addstr(&msgbuf, oid_to_hex(&parent->object.oid));
 538                 }
 539                 strbuf_addstr(&msgbuf, ".\n");
 540         } else {
 541                 const char *p;
 542
 543                 base = parent;
 544                 base_label = msg.parent_label;
 545                 next = commit;
 546                 next_label = msg.label;
 547
 548                 /*
 549                  * Append the commit log message to msgbuf; it starts
 550                  * after the tree, parent, author, committer
 551                  * information followed by "\n\n".
 552                  */
 553                 p = strstr(msg.message, "\n\n");
 554                 if (p)
 555                         strbuf_addstr(&msgbuf, skip_blank_lines(p + 2));
 556
 557                 if (opts->record_origin) {
 558                         if (!has_conforming_footer(&msgbuf, NULL, 0))
 559                                 strbuf_addch(&msgbuf, '\n');
 560                         strbuf_addstr(&msgbuf, cherry_picked_prefix);
 561                         strbuf_addstr(&msgbuf, oid_to_hex(&commit->object.oid));
 562                         strbuf_addstr(&msgbuf, ")\n");
 563                 }
 564         }
 565
 566         if (!opts->strategy || !strcmp(opts->strategy, "recursive") || opts->action == REPLAY_REVERT) {
 567                 res = do_recursive_merge(base, next, base_label, next_label,
 568                                          head, &msgbuf, opts);
 569                 if (res < 0)
 570                         return res;
 571                 res |= write_message(&msgbuf, git_path_merge_msg());
 572         } else {
 573                 struct commit_list *common = NULL;
 574                 struct commit_list *remotes = NULL;
 575
 576                 res = write_message(&msgbuf, git_path_merge_msg());
 577
 578                 commit_list_insert(base, &common);
 579                 commit_list_insert(next, &remotes);
 580                 res |= try_merge_command(opts->strategy, opts->xopts_nr, opts->xopts,
 581                                         common, sha1_to_hex(head), remotes);
 582                 free_commit_list(common);
 583                 free_commit_list(remotes);
 584         }
 585
 586         /*
 587          * If the merge was clean or if it failed due to conflict, we write
 588          * CHERRY_PICK_HEAD for the subsequent invocation of commit to use.
 589          * However, if the merge did not even start, then we don't want to
 590          * write it at all.
 591          */
 592         if (opts->action == REPLAY_PICK && !opts->no_commit && (res == 0 || res == 1) &&
 593             update_ref(NULL, "CHERRY_PICK_HEAD", commit->object.oid.hash, NULL,
 594                        REF_NODEREF, UPDATE_REFS_MSG_ON_ERR))
 595                 res = -1;
 596         if (opts->action == REPLAY_REVERT && ((opts->no_commit && res == 0) || res == 1) &&
 597             update_ref(NULL, "REVERT_HEAD", commit->object.oid.hash, NULL,
 598                        REF_NODEREF, UPDATE_REFS_MSG_ON_ERR))
 599                 res = -1;
 600
 601         if (res) {
 602                 error(opts->action == REPLAY_REVERT
 603                       ? _("could not revert %s... %s")
 604                       : _("could not apply %s... %s"),
 605                       find_unique_abbrev(commit->object.oid.hash, DEFAULT_ABBREV),
 606                       msg.subject);
 607                 print_advice(res == 1, opts);
 608                 rerere(opts->allow_rerere_auto);
 609                 goto leave;
 610         }
 611
 612         allow = allow_empty(opts, commit);
 613         if (allow < 0) {
 614                 res = allow;
 615                 goto leave;
 616         }
 617         if (!opts->no_commit)
 618                 res = run_git_commit(git_path_merge_msg(), opts, allow);
 619
 620 leave:
 621         free_message(commit, &msg);
 622
 623         return res;
 624 }
 625
 626 static int prepare_revs(struct replay_opts *opts)
 627 {
 628         /*
 629          * picking (but not reverting) ranges (but not individual revisions)
 630          * should be done in reverse
 631          */
 632         if (opts->action == REPLAY_PICK && !opts->revs->no_walk)
 633                 opts->revs->reverse ^= 1;
 634
 635         if (prepare_revision_walk(opts->revs))
 636                 return error(_("revision walk setup failed"));
 637
 638         if (!opts->revs->commits)
 639                 return error(_("empty commit set passed"));
 640         return 0;
 641 }
 642
 643 static int read_and_refresh_cache(struct replay_opts *opts)
 644 {
 645         static struct lock_file index_lock;
 646         int index_fd = hold_locked_index(&index_lock, 0);
 647         if (read_index_preload(&the_index, NULL) < 0) {
 648                 rollback_lock_file(&index_lock);
 649                 return error(_("git %s: failed to read the index"),
 650                         action_name(opts));
 651         }
 652         refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
 653         if (the_index.cache_changed && index_fd >= 0) {
 654                 if (write_locked_index(&the_index, &index_lock, COMMIT_LOCK)) {
 655                         rollback_lock_file(&index_lock);
 656                         return error(_("git %s: failed to refresh the index"),
 657                                 action_name(opts));
 658                 }
 659         }
 660         rollback_lock_file(&index_lock);
 661         return 0;
 662 }
 663
 664 static int format_todo(struct strbuf *buf, struct commit_list *todo_list,
 665                 struct replay_opts *opts)
 666 {
 667         struct commit_list *cur = NULL;
 668         const char *sha1_abbrev = NULL;
 669         const char *action_str = opts->action == REPLAY_REVERT ? "revert" : "pick";
 670         const char *subject;
 671         int subject_len;
 672
 673         for (cur = todo_list; cur; cur = cur->next) {
 674                 const char *commit_buffer = get_commit_buffer(cur->item, NULL);
 675                 sha1_abbrev = find_unique_abbrev(cur->item->object.oid.hash, DEFAULT_ABBREV);
 676                 subject_len = find_commit_subject(commit_buffer, &subject);
 677                 strbuf_addf(buf, "%s %s %.*s\n", action_str, sha1_abbrev,
 678                         subject_len, subject);
 679                 unuse_commit_buffer(cur->item, commit_buffer);
 680         }
 681         return 0;
 682 }
 683
 684 static struct commit *parse_insn_line(char *bol, char *eol, struct replay_opts *opts)
 685 {
 686         unsigned char commit_sha1[20];
 687         enum replay_action action;
 688         char *end_of_object_name;
 689         int saved, status, padding;
 690
 691         if (starts_with(bol, "pick")) {
 692                 action = REPLAY_PICK;
 693                 bol += strlen("pick");
 694         } else if (starts_with(bol, "revert")) {
 695                 action = REPLAY_REVERT;
 696                 bol += strlen("revert");
 697         } else
 698                 return NULL;
 699
 700         /* Eat up extra spaces/ tabs before object name */
 701         padding = strspn(bol, " \t");
 702         if (!padding)
 703                 return NULL;
 704         bol += padding;
 705
 706         end_of_object_name = bol + strcspn(bol, " \t\n");
 707         saved = *end_of_object_name;
 708         *end_of_object_name = '\0';
 709         status = get_sha1(bol, commit_sha1);
 710         *end_of_object_name = saved;
 711
 712         /*
 713          * Verify that the action matches up with the one in
 714          * opts; we don't support arbitrary instructions
 715          */
 716         if (action != opts->action) {
 717                 if (action == REPLAY_REVERT)
 718                       error((opts->action == REPLAY_REVERT)
 719                             ? _("Cannot revert during another revert.")
 720                             : _("Cannot revert during a cherry-pick."));
 721                 else
 722                       error((opts->action == REPLAY_REVERT)
 723                             ? _("Cannot cherry-pick during a revert.")
 724                             : _("Cannot cherry-pick during another cherry-pick."));
 725                 return NULL;
 726         }
 727
 728         if (status < 0)
 729                 return NULL;
 730
 731         return lookup_commit_reference(commit_sha1);
 732 }
 733
 734 static int parse_insn_buffer(char *buf, struct commit_list **todo_list,
 735                         struct replay_opts *opts)
 736 {
 737         struct commit_list **next = todo_list;
 738         struct commit *commit;
 739         char *p = buf;
 740         int i;
 741
 742         for (i = 1; *p; i++) {
 743                 char *eol = strchrnul(p, '\n');
 744                 commit = parse_insn_line(p, eol, opts);
 745                 if (!commit)
 746                         return error(_("Could not parse line %d."), i);
 747                 next = commit_list_append(commit, next);
 748                 p = *eol ? eol + 1 : eol;
 749         }
 750         if (!*todo_list)
 751                 return error(_("No commits parsed."));
 752         return 0;
 753 }
 754
 755 static int read_populate_todo(struct commit_list **todo_list,
 756                         struct replay_opts *opts)
 757 {
 758         struct strbuf buf = STRBUF_INIT;
 759         int fd, res;
 760
 761         fd = open(git_path_todo_file(), O_RDONLY);
 762         if (fd < 0)
 763                 return error_errno(_("Could not open %s"),
 764                                    git_path_todo_file());
 765         if (strbuf_read(&buf, fd, 0) < 0) {
 766                 close(fd);
 767                 strbuf_release(&buf);
 768                 return error(_("Could not read %s."), git_path_todo_file());
 769         }
 770         close(fd);
 771
 772         res = parse_insn_buffer(buf.buf, todo_list, opts);
 773         strbuf_release(&buf);
 774         if (res)
 775                 return error(_("Unusable instruction sheet: %s"),
 776                         git_path_todo_file());
 777         return 0;
 778 }
 779
 780 static int populate_opts_cb(const char *key, const char *value, void *data)
 781 {
 782         struct replay_opts *opts = data;
 783         int error_flag = 1;
 784
 785         if (!value)
 786                 error_flag = 0;
 787         else if (!strcmp(key, "options.no-commit"))
 788                 opts->no_commit = git_config_bool_or_int(key, value, &error_flag);
 789         else if (!strcmp(key, "options.edit"))
 790                 opts->edit = git_config_bool_or_int(key, value, &error_flag);
 791         else if (!strcmp(key, "options.signoff"))
 792                 opts->signoff = git_config_bool_or_int(key, value, &error_flag);
 793         else if (!strcmp(key, "options.record-origin"))
 794                 opts->record_origin = git_config_bool_or_int(key, value, &error_flag);
 795         else if (!strcmp(key, "options.allow-ff"))
 796                 opts->allow_ff = git_config_bool_or_int(key, value, &error_flag);
 797         else if (!strcmp(key, "options.mainline"))
 798                 opts->mainline = git_config_int(key, value);
 799         else if (!strcmp(key, "options.strategy"))
 800                 git_config_string(&opts->strategy, key, value);
 801         else if (!strcmp(key, "options.gpg-sign"))
 802                 git_config_string(&opts->gpg_sign, key, value);
 803         else if (!strcmp(key, "options.strategy-option")) {
 804                 ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
 805                 opts->xopts[opts->xopts_nr++] = xstrdup(value);
 806         } else
 807                 return error(_("Invalid key: %s"), key);
 808
 809         if (!error_flag)
 810                 return error(_("Invalid value for %s: %s"), key, value);
 811
 812         return 0;
 813 }
 814
 815 static int read_populate_opts(struct replay_opts **opts)
 816 {
 817         if (!file_exists(git_path_opts_file()))
 818                 return 0;
 819         /*
 820          * The function git_parse_source(), called from git_config_from_file(),
 821          * may die() in case of a syntactically incorrect file. We do not care
 822          * about this case, though, because we wrote that file ourselves, so we
 823          * are pretty certain that it is syntactically correct.
 824          */
 825         if (git_config_from_file(populate_opts_cb, git_path_opts_file(), *opts) < 0)
 826                 return error(_("Malformed options sheet: %s"),
 827                         git_path_opts_file());
 828         return 0;
 829 }
 830
 831 static int walk_revs_populate_todo(struct commit_list **todo_list,
 832                                 struct replay_opts *opts)
 833 {
 834         struct commit *commit;
 835         struct commit_list **next;
 836
 837         if (prepare_revs(opts))
 838                 return -1;
 839
 840         next = todo_list;
 841         while ((commit = get_revision(opts->revs)))
 842                 next = commit_list_append(commit, next);
 843         return 0;
 844 }
 845
 846 static int create_seq_dir(void)
 847 {
 848         if (file_exists(git_path_seq_dir())) {
 849                 error(_("a cherry-pick or revert is already in progress"));
 850                 advise(_("try \"git cherry-pick (--continue | --quit | --abort)\""));
 851                 return -1;
 852         }
 853         else if (mkdir(git_path_seq_dir(), 0777) < 0)
 854                 return error_errno(_("Could not create sequencer directory %s"),
 855                                    git_path_seq_dir());
 856         return 0;
 857 }
 858
 859 static int save_head(const char *head)
 860 {
 861         static struct lock_file head_lock;
 862         struct strbuf buf = STRBUF_INIT;
 863         int fd;
 864
 865         fd = hold_lock_file_for_update(&head_lock, git_path_head_file(), 0);
 866         if (fd < 0) {
 867                 rollback_lock_file(&head_lock);
 868                 return error_errno(_("Could not lock HEAD"));
 869         }
 870         strbuf_addf(&buf, "%s\n", head);
 871         if (write_in_full(fd, buf.buf, buf.len) < 0) {
 872                 rollback_lock_file(&head_lock);
 873                 return error_errno(_("Could not write to %s"),
 874                                    git_path_head_file());
 875         }
 876         if (commit_lock_file(&head_lock) < 0) {
 877                 rollback_lock_file(&head_lock);
 878                 return error(_("Error wrapping up %s."), git_path_head_file());
 879         }
 880         return 0;
 881 }
 882
 883 static int reset_for_rollback(const unsigned char *sha1)
 884 {
 885         const char *argv[4];    /* reset --merge <arg> + NULL */
 886         argv[0] = "reset";
 887         argv[1] = "--merge";
 888         argv[2] = sha1_to_hex(sha1);
 889         argv[3] = NULL;
 890         return run_command_v_opt(argv, RUN_GIT_CMD);
 891 }
 892
 893 static int rollback_single_pick(void)
 894 {
 895         unsigned char head_sha1[20];
 896
 897         if (!file_exists(git_path_cherry_pick_head()) &&
 898             !file_exists(git_path_revert_head()))
 899                 return error(_("no cherry-pick or revert in progress"));
 900         if (read_ref_full("HEAD", 0, head_sha1, NULL))
 901                 return error(_("cannot resolve HEAD"));
 902         if (is_null_sha1(head_sha1))
 903                 return error(_("cannot abort from a branch yet to be born"));
 904         return reset_for_rollback(head_sha1);
 905 }
 906
 907 static int sequencer_rollback(struct replay_opts *opts)
 908 {
 909         FILE *f;
 910         unsigned char sha1[20];
 911         struct strbuf buf = STRBUF_INIT;
 912
 913         f = fopen(git_path_head_file(), "r");
 914         if (!f && errno == ENOENT) {
 915                 /*
 916                  * There is no multiple-cherry-pick in progress.
 917                  * If CHERRY_PICK_HEAD or REVERT_HEAD indicates
 918                  * a single-cherry-pick in progress, abort that.
 919                  */
 920                 return rollback_single_pick();
 921         }
 922         if (!f)
 923                 return error_errno(_("cannot open %s"), git_path_head_file());
 924         if (strbuf_getline_lf(&buf, f)) {
 925                 error(_("cannot read %s: %s"), git_path_head_file(),
 926                       ferror(f) ?  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                         git_path_head_file());
 934                 goto fail;
 935         }
 936         if (is_null_sha1(sha1)) {
 937                 error(_("cannot abort from a branch yet to be born"));
 938                 goto fail;
 939         }
 940         if (reset_for_rollback(sha1))
 941                 goto fail;
 942         remove_sequencer_state();
 943         strbuf_release(&buf);
 944         return 0;
 945 fail:
 946         strbuf_release(&buf);
 947         return -1;
 948 }
 949
 950 static int save_todo(struct commit_list *todo_list, struct replay_opts *opts)
 951 {
 952         static struct lock_file todo_lock;
 953         struct strbuf buf = STRBUF_INIT;
 954         int fd;
 955
 956         fd = hold_lock_file_for_update(&todo_lock, git_path_todo_file(), 0);
 957         if (fd < 0)
 958                 return error_errno(_("Could not lock '%s'"),
 959                                    git_path_todo_file());
 960         if (format_todo(&buf, todo_list, opts) < 0) {
 961                 strbuf_release(&buf);
 962                 return error(_("Could not format %s."), git_path_todo_file());
 963         }
 964         if (write_in_full(fd, buf.buf, buf.len) < 0) {
 965                 strbuf_release(&buf);
 966                 return error_errno(_("Could not write to %s"),
 967                                    git_path_todo_file());
 968         }
 969         if (commit_lock_file(&todo_lock) < 0) {
 970                 strbuf_release(&buf);
 971                 return error(_("Error wrapping up %s."), git_path_todo_file());
 972         }
 973         strbuf_release(&buf);
 974         return 0;
 975 }
 976
 977 static int save_opts(struct replay_opts *opts)
 978 {
 979         const char *opts_file = git_path_opts_file();
 980         int res = 0;
 981
 982         if (opts->no_commit)
 983                 res |= git_config_set_in_file_gently(opts_file, "options.no-commit", "true");
 984         if (opts->edit)
 985                 res |= git_config_set_in_file_gently(opts_file, "options.edit", "true");
 986         if (opts->signoff)
 987                 res |= git_config_set_in_file_gently(opts_file, "options.signoff", "true");
 988         if (opts->record_origin)
 989                 res |= git_config_set_in_file_gently(opts_file, "options.record-origin", "true");
 990         if (opts->allow_ff)
 991                 res |= git_config_set_in_file_gently(opts_file, "options.allow-ff", "true");
 992         if (opts->mainline) {
 993                 struct strbuf buf = STRBUF_INIT;
 994                 strbuf_addf(&buf, "%d", opts->mainline);
 995                 res |= git_config_set_in_file_gently(opts_file, "options.mainline", buf.buf);
 996                 strbuf_release(&buf);
 997         }
 998         if (opts->strategy)
 999                 res |= git_config_set_in_file_gently(opts_file, "options.strategy", opts->strategy);
1000         if (opts->gpg_sign)
1001                 res |= git_config_set_in_file_gently(opts_file, "options.gpg-sign", opts->gpg_sign);
1002         if (opts->xopts) {
1003                 int i;
1004                 for (i = 0; i < opts->xopts_nr; i++)
1005                         res |= git_config_set_multivar_in_file_gently(opts_file,
1006                                                         "options.strategy-option",
1007                                                         opts->xopts[i], "^$", 0);
1008         }
1009         return res;
1010 }
1011
1012 static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
1013 {
1014         struct commit_list *cur;
1015         int res;
1016
1017         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
1018         if (opts->allow_ff)
1019                 assert(!(opts->signoff || opts->no_commit ||
1020                                 opts->record_origin || opts->edit));
1021         if (read_and_refresh_cache(opts))
1022                 return -1;
1023
1024         for (cur = todo_list; cur; cur = cur->next) {
1025                 if (save_todo(cur, opts))
1026                         return -1;
1027                 res = do_pick_commit(cur->item, opts);
1028                 if (res)
1029                         return res;
1030         }
1031
1032         /*
1033          * Sequence of picks finished successfully; cleanup by
1034          * removing the .git/sequencer directory
1035          */
1036         remove_sequencer_state();
1037         return 0;
1038 }
1039
1040 static int continue_single_pick(void)
1041 {
1042         const char *argv[] = { "commit", NULL };
1043
1044         if (!file_exists(git_path_cherry_pick_head()) &&
1045             !file_exists(git_path_revert_head()))
1046                 return error(_("no cherry-pick or revert in progress"));
1047         return run_command_v_opt(argv, RUN_GIT_CMD);
1048 }
1049
1050 static int sequencer_continue(struct replay_opts *opts)
1051 {
1052         struct commit_list *todo_list = NULL;
1053
1054         if (!file_exists(git_path_todo_file()))
1055                 return continue_single_pick();
1056         if (read_populate_opts(&opts) ||
1057                         read_populate_todo(&todo_list, opts))
1058                 return -1;
1059
1060         /* Verify that the conflict has been resolved */
1061         if (file_exists(git_path_cherry_pick_head()) ||
1062             file_exists(git_path_revert_head())) {
1063                 int ret = continue_single_pick();
1064                 if (ret)
1065                         return ret;
1066         }
1067         if (index_differs_from("HEAD", 0))
1068                 return error_dirty_index(opts);
1069         todo_list = todo_list->next;
1070         return pick_commits(todo_list, opts);
1071 }
1072
1073 static int single_pick(struct commit *cmit, struct replay_opts *opts)
1074 {
1075         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
1076         return do_pick_commit(cmit, opts);
1077 }
1078
1079 int sequencer_pick_revisions(struct replay_opts *opts)
1080 {
1081         struct commit_list *todo_list = NULL;
1082         unsigned char sha1[20];
1083         int i;
1084
1085         if (opts->subcommand == REPLAY_NONE)
1086                 assert(opts->revs);
1087
1088         if (read_and_refresh_cache(opts))
1089                 return -1;
1090
1091         /*
1092          * Decide what to do depending on the arguments; a fresh
1093          * cherry-pick should be handled differently from an existing
1094          * one that is being continued
1095          */
1096         if (opts->subcommand == REPLAY_REMOVE_STATE) {
1097                 remove_sequencer_state();
1098                 return 0;
1099         }
1100         if (opts->subcommand == REPLAY_ROLLBACK)
1101                 return sequencer_rollback(opts);
1102         if (opts->subcommand == REPLAY_CONTINUE)
1103                 return sequencer_continue(opts);
1104
1105         for (i = 0; i < opts->revs->pending.nr; i++) {
1106                 unsigned char sha1[20];
1107                 const char *name = opts->revs->pending.objects[i].name;
1108
1109                 /* This happens when using --stdin. */
1110                 if (!strlen(name))
1111                         continue;
1112
1113                 if (!get_sha1(name, sha1)) {
1114                         if (!lookup_commit_reference_gently(sha1, 1)) {
1115                                 enum object_type type = sha1_object_info(sha1, NULL);
1116                                 return error(_("%s: can't cherry-pick a %s"),
1117                                         name, typename(type));
1118                         }
1119                 } else
1120                         return error(_("%s: bad revision"), name);
1121         }
1122
1123         /*
1124          * If we were called as "git cherry-pick <commit>", just
1125          * cherry-pick/revert it, set CHERRY_PICK_HEAD /
1126          * REVERT_HEAD, and don't touch the sequencer state.
1127          * This means it is possible to cherry-pick in the middle
1128          * of a cherry-pick sequence.
1129          */
1130         if (opts->revs->cmdline.nr == 1 &&
1131             opts->revs->cmdline.rev->whence == REV_CMD_REV &&
1132             opts->revs->no_walk &&
1133             !opts->revs->cmdline.rev->flags) {
1134                 struct commit *cmit;
1135                 if (prepare_revision_walk(opts->revs))
1136                         return error(_("revision walk setup failed"));
1137                 cmit = get_revision(opts->revs);
1138                 if (!cmit || get_revision(opts->revs))
1139                         return error("BUG: expected exactly one commit from walk");
1140                 return single_pick(cmit, opts);
1141         }
1142
1143         /*
1144          * Start a new cherry-pick/ revert sequence; but
1145          * first, make sure that an existing one isn't in
1146          * progress
1147          */
1148
1149         if (walk_revs_populate_todo(&todo_list, opts) ||
1150                         create_seq_dir() < 0)
1151                 return -1;
1152         if (get_sha1("HEAD", sha1) && (opts->action == REPLAY_REVERT))
1153                 return error(_("Can't revert as initial commit"));
1154         if (save_head(sha1_to_hex(sha1)))
1155                 return -1;
1156         if (save_opts(opts))
1157                 return -1;
1158         return pick_commits(todo_list, opts);
1159 }
1160
1161 void append_signoff(struct strbuf *msgbuf, int ignore_footer, unsigned flag)
1162 {
1163         unsigned no_dup_sob = flag & APPEND_SIGNOFF_DEDUP;
1164         struct strbuf sob = STRBUF_INIT;
1165         int has_footer;
1166
1167         strbuf_addstr(&sob, sign_off_header);
1168         strbuf_addstr(&sob, fmt_name(getenv("GIT_COMMITTER_NAME"),
1169                                 getenv("GIT_COMMITTER_EMAIL")));
1170         strbuf_addch(&sob, '\n');
1171
1172         /*
1173          * If the whole message buffer is equal to the sob, pretend that we
1174          * found a conforming footer with a matching sob
1175          */
1176         if (msgbuf->len - ignore_footer == sob.len &&
1177             !strncmp(msgbuf->buf, sob.buf, sob.len))
1178                 has_footer = 3;
1179         else
1180                 has_footer = has_conforming_footer(msgbuf, &sob, ignore_footer);
1181
1182         if (!has_footer) {
1183                 const char *append_newlines = NULL;
1184                 size_t len = msgbuf->len - ignore_footer;
1185
1186                 if (!len) {
1187                         /*
1188                          * The buffer is completely empty.  Leave foom for
1189                          * the title and body to be filled in by the user.
1190                          */
1191                         append_newlines = "\n\n";
1192                 } else if (msgbuf->buf[len - 1] != '\n') {
1193                         /*
1194                          * Incomplete line.  Complete the line and add a
1195                          * blank one so that there is an empty line between
1196                          * the message body and the sob.
1197                          */
1198                         append_newlines = "\n\n";
1199                 } else if (len == 1) {
1200                         /*
1201                          * Buffer contains a single newline.  Add another
1202                          * so that we leave room for the title and body.
1203                          */
1204                         append_newlines = "\n";
1205                 } else if (msgbuf->buf[len - 2] != '\n') {
1206                         /*
1207                          * Buffer ends with a single newline.  Add another
1208                          * so that there is an empty line between the message
1209                          * body and the sob.
1210                          */
1211                         append_newlines = "\n";
1212                 } /* else, the buffer already ends with two newlines. */
1213
1214                 if (append_newlines)
1215                         strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0,
1216                                 append_newlines, strlen(append_newlines));
1217         }
1218
1219         if (has_footer != 3 && (!no_dup_sob || has_footer != 2))
1220                 strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0,
1221                                 sob.buf, sob.len);
1222
1223         strbuf_release(&sob);
1224 }