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                 exit(128); /* 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                 return error(_("git %s: failed to read the index"),
 649                         action_name(opts));
 650         refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
 651         if (the_index.cache_changed && index_fd >= 0) {
 652                 if (write_locked_index(&the_index, &index_lock, COMMIT_LOCK))
 653                         return error(_("git %s: failed to refresh the index"),
 654                                 action_name(opts));
 655         }
 656         rollback_lock_file(&index_lock);
 657         return 0;
 658 }
 659
 660 static int format_todo(struct strbuf *buf, struct commit_list *todo_list,
 661                 struct replay_opts *opts)
 662 {
 663         struct commit_list *cur = NULL;
 664         const char *sha1_abbrev = NULL;
 665         const char *action_str = opts->action == REPLAY_REVERT ? "revert" : "pick";
 666         const char *subject;
 667         int subject_len;
 668
 669         for (cur = todo_list; cur; cur = cur->next) {
 670                 const char *commit_buffer = get_commit_buffer(cur->item, NULL);
 671                 sha1_abbrev = find_unique_abbrev(cur->item->object.oid.hash, DEFAULT_ABBREV);
 672                 subject_len = find_commit_subject(commit_buffer, &subject);
 673                 strbuf_addf(buf, "%s %s %.*s\n", action_str, sha1_abbrev,
 674                         subject_len, subject);
 675                 unuse_commit_buffer(cur->item, commit_buffer);
 676         }
 677         return 0;
 678 }
 679
 680 static struct commit *parse_insn_line(char *bol, char *eol, struct replay_opts *opts)
 681 {
 682         unsigned char commit_sha1[20];
 683         enum replay_action action;
 684         char *end_of_object_name;
 685         int saved, status, padding;
 686
 687         if (starts_with(bol, "pick")) {
 688                 action = REPLAY_PICK;
 689                 bol += strlen("pick");
 690         } else if (starts_with(bol, "revert")) {
 691                 action = REPLAY_REVERT;
 692                 bol += strlen("revert");
 693         } else
 694                 return NULL;
 695
 696         /* Eat up extra spaces/ tabs before object name */
 697         padding = strspn(bol, " \t");
 698         if (!padding)
 699                 return NULL;
 700         bol += padding;
 701
 702         end_of_object_name = bol + strcspn(bol, " \t\n");
 703         saved = *end_of_object_name;
 704         *end_of_object_name = '\0';
 705         status = get_sha1(bol, commit_sha1);
 706         *end_of_object_name = saved;
 707
 708         /*
 709          * Verify that the action matches up with the one in
 710          * opts; we don't support arbitrary instructions
 711          */
 712         if (action != opts->action) {
 713                 if (action == REPLAY_REVERT)
 714                       error((opts->action == REPLAY_REVERT)
 715                             ? _("Cannot revert during another revert.")
 716                             : _("Cannot revert during a cherry-pick."));
 717                 else
 718                       error((opts->action == REPLAY_REVERT)
 719                             ? _("Cannot cherry-pick during a revert.")
 720                             : _("Cannot cherry-pick during another cherry-pick."));
 721                 return NULL;
 722         }
 723
 724         if (status < 0)
 725                 return NULL;
 726
 727         return lookup_commit_reference(commit_sha1);
 728 }
 729
 730 static int parse_insn_buffer(char *buf, struct commit_list **todo_list,
 731                         struct replay_opts *opts)
 732 {
 733         struct commit_list **next = todo_list;
 734         struct commit *commit;
 735         char *p = buf;
 736         int i;
 737
 738         for (i = 1; *p; i++) {
 739                 char *eol = strchrnul(p, '\n');
 740                 commit = parse_insn_line(p, eol, opts);
 741                 if (!commit)
 742                         return error(_("Could not parse line %d."), i);
 743                 next = commit_list_append(commit, next);
 744                 p = *eol ? eol + 1 : eol;
 745         }
 746         if (!*todo_list)
 747                 return error(_("No commits parsed."));
 748         return 0;
 749 }
 750
 751 static int read_populate_todo(struct commit_list **todo_list,
 752                         struct replay_opts *opts)
 753 {
 754         struct strbuf buf = STRBUF_INIT;
 755         int fd, res;
 756
 757         fd = open(git_path_todo_file(), O_RDONLY);
 758         if (fd < 0)
 759                 return error_errno(_("Could not open %s"),
 760                                    git_path_todo_file());
 761         if (strbuf_read(&buf, fd, 0) < 0) {
 762                 close(fd);
 763                 strbuf_release(&buf);
 764                 return error(_("Could not read %s."), git_path_todo_file());
 765         }
 766         close(fd);
 767
 768         res = parse_insn_buffer(buf.buf, todo_list, opts);
 769         strbuf_release(&buf);
 770         if (res)
 771                 return error(_("Unusable instruction sheet: %s"),
 772                         git_path_todo_file());
 773         return 0;
 774 }
 775
 776 static int populate_opts_cb(const char *key, const char *value, void *data)
 777 {
 778         struct replay_opts *opts = data;
 779         int error_flag = 1;
 780
 781         if (!value)
 782                 error_flag = 0;
 783         else if (!strcmp(key, "options.no-commit"))
 784                 opts->no_commit = git_config_bool_or_int(key, value, &error_flag);
 785         else if (!strcmp(key, "options.edit"))
 786                 opts->edit = git_config_bool_or_int(key, value, &error_flag);
 787         else if (!strcmp(key, "options.signoff"))
 788                 opts->signoff = git_config_bool_or_int(key, value, &error_flag);
 789         else if (!strcmp(key, "options.record-origin"))
 790                 opts->record_origin = git_config_bool_or_int(key, value, &error_flag);
 791         else if (!strcmp(key, "options.allow-ff"))
 792                 opts->allow_ff = git_config_bool_or_int(key, value, &error_flag);
 793         else if (!strcmp(key, "options.mainline"))
 794                 opts->mainline = git_config_int(key, value);
 795         else if (!strcmp(key, "options.strategy"))
 796                 git_config_string(&opts->strategy, key, value);
 797         else if (!strcmp(key, "options.gpg-sign"))
 798                 git_config_string(&opts->gpg_sign, key, value);
 799         else if (!strcmp(key, "options.strategy-option")) {
 800                 ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
 801                 opts->xopts[opts->xopts_nr++] = xstrdup(value);
 802         } else
 803                 return error(_("Invalid key: %s"), key);
 804
 805         if (!error_flag)
 806                 return error(_("Invalid value for %s: %s"), key, value);
 807
 808         return 0;
 809 }
 810
 811 static int read_populate_opts(struct replay_opts **opts)
 812 {
 813         if (!file_exists(git_path_opts_file()))
 814                 return 0;
 815         /*
 816          * The function git_parse_source(), called from git_config_from_file(),
 817          * may die() in case of a syntactically incorrect file. We do not care
 818          * about this case, though, because we wrote that file ourselves, so we
 819          * are pretty certain that it is syntactically correct.
 820          */
 821         if (git_config_from_file(populate_opts_cb, git_path_opts_file(), *opts) < 0)
 822                 return error(_("Malformed options sheet: %s"),
 823                         git_path_opts_file());
 824         return 0;
 825 }
 826
 827 static int walk_revs_populate_todo(struct commit_list **todo_list,
 828                                 struct replay_opts *opts)
 829 {
 830         struct commit *commit;
 831         struct commit_list **next;
 832
 833         if (prepare_revs(opts))
 834                 return -1;
 835
 836         next = todo_list;
 837         while ((commit = get_revision(opts->revs)))
 838                 next = commit_list_append(commit, next);
 839         return 0;
 840 }
 841
 842 static int create_seq_dir(void)
 843 {
 844         if (file_exists(git_path_seq_dir())) {
 845                 error(_("a cherry-pick or revert is already in progress"));
 846                 advise(_("try \"git cherry-pick (--continue | --quit | --abort)\""));
 847                 return -1;
 848         }
 849         else if (mkdir(git_path_seq_dir(), 0777) < 0)
 850                 return error_errno(_("Could not create sequencer directory %s"),
 851                                    git_path_seq_dir());
 852         return 0;
 853 }
 854
 855 static int save_head(const char *head)
 856 {
 857         static struct lock_file head_lock;
 858         struct strbuf buf = STRBUF_INIT;
 859         int fd;
 860
 861         fd = hold_lock_file_for_update(&head_lock, git_path_head_file(), 0);
 862         if (fd < 0) {
 863                 rollback_lock_file(&head_lock);
 864                 return error_errno(_("Could not lock HEAD"));
 865         }
 866         strbuf_addf(&buf, "%s\n", head);
 867         if (write_in_full(fd, buf.buf, buf.len) < 0) {
 868                 rollback_lock_file(&head_lock);
 869                 return error_errno(_("Could not write to %s"),
 870                                    git_path_head_file());
 871         }
 872         if (commit_lock_file(&head_lock) < 0) {
 873                 rollback_lock_file(&head_lock);
 874                 return error(_("Error wrapping up %s."), git_path_head_file());
 875         }
 876         return 0;
 877 }
 878
 879 static int reset_for_rollback(const unsigned char *sha1)
 880 {
 881         const char *argv[4];    /* reset --merge <arg> + NULL */
 882         argv[0] = "reset";
 883         argv[1] = "--merge";
 884         argv[2] = sha1_to_hex(sha1);
 885         argv[3] = NULL;
 886         return run_command_v_opt(argv, RUN_GIT_CMD);
 887 }
 888
 889 static int rollback_single_pick(void)
 890 {
 891         unsigned char head_sha1[20];
 892
 893         if (!file_exists(git_path_cherry_pick_head()) &&
 894             !file_exists(git_path_revert_head()))
 895                 return error(_("no cherry-pick or revert in progress"));
 896         if (read_ref_full("HEAD", 0, head_sha1, NULL))
 897                 return error(_("cannot resolve HEAD"));
 898         if (is_null_sha1(head_sha1))
 899                 return error(_("cannot abort from a branch yet to be born"));
 900         return reset_for_rollback(head_sha1);
 901 }
 902
 903 static int sequencer_rollback(struct replay_opts *opts)
 904 {
 905         FILE *f;
 906         unsigned char sha1[20];
 907         struct strbuf buf = STRBUF_INIT;
 908
 909         f = fopen(git_path_head_file(), "r");
 910         if (!f && errno == ENOENT) {
 911                 /*
 912                  * There is no multiple-cherry-pick in progress.
 913                  * If CHERRY_PICK_HEAD or REVERT_HEAD indicates
 914                  * a single-cherry-pick in progress, abort that.
 915                  */
 916                 return rollback_single_pick();
 917         }
 918         if (!f)
 919                 return error_errno(_("cannot open %s"), git_path_head_file());
 920         if (strbuf_getline_lf(&buf, f)) {
 921                 error(_("cannot read %s: %s"), git_path_head_file(),
 922                       ferror(f) ?  strerror(errno) : _("unexpected end of file"));
 923                 fclose(f);
 924                 goto fail;
 925         }
 926         fclose(f);
 927         if (get_sha1_hex(buf.buf, sha1) || buf.buf[40] != '\0') {
 928                 error(_("stored pre-cherry-pick HEAD file '%s' is corrupt"),
 929                         git_path_head_file());
 930                 goto fail;
 931         }
 932         if (is_null_sha1(sha1)) {
 933                 error(_("cannot abort from a branch yet to be born"));
 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 int save_todo(struct commit_list *todo_list, struct replay_opts *opts)
 947 {
 948         static struct lock_file todo_lock;
 949         struct strbuf buf = STRBUF_INIT;
 950         int fd;
 951
 952         fd = hold_lock_file_for_update(&todo_lock, git_path_todo_file(), 0);
 953         if (fd < 0)
 954                 return error_errno(_("Could not lock '%s'"),
 955                                    git_path_todo_file());
 956         if (format_todo(&buf, todo_list, opts) < 0) {
 957                 strbuf_release(&buf);
 958                 return error(_("Could not format %s."), git_path_todo_file());
 959         }
 960         if (write_in_full(fd, buf.buf, buf.len) < 0) {
 961                 strbuf_release(&buf);
 962                 return error_errno(_("Could not write to %s"),
 963                                    git_path_todo_file());
 964         }
 965         if (commit_lock_file(&todo_lock) < 0) {
 966                 strbuf_release(&buf);
 967                 return error(_("Error wrapping up %s."), git_path_todo_file());
 968         }
 969         strbuf_release(&buf);
 970         return 0;
 971 }
 972
 973 static void save_opts(struct replay_opts *opts)
 974 {
 975         const char *opts_file = git_path_opts_file();
 976
 977         if (opts->no_commit)
 978                 git_config_set_in_file(opts_file, "options.no-commit", "true");
 979         if (opts->edit)
 980                 git_config_set_in_file(opts_file, "options.edit", "true");
 981         if (opts->signoff)
 982                 git_config_set_in_file(opts_file, "options.signoff", "true");
 983         if (opts->record_origin)
 984                 git_config_set_in_file(opts_file, "options.record-origin", "true");
 985         if (opts->allow_ff)
 986                 git_config_set_in_file(opts_file, "options.allow-ff", "true");
 987         if (opts->mainline) {
 988                 struct strbuf buf = STRBUF_INIT;
 989                 strbuf_addf(&buf, "%d", opts->mainline);
 990                 git_config_set_in_file(opts_file, "options.mainline", buf.buf);
 991                 strbuf_release(&buf);
 992         }
 993         if (opts->strategy)
 994                 git_config_set_in_file(opts_file, "options.strategy", opts->strategy);
 995         if (opts->gpg_sign)
 996                 git_config_set_in_file(opts_file, "options.gpg-sign", opts->gpg_sign);
 997         if (opts->xopts) {
 998                 int i;
 999                 for (i = 0; i < opts->xopts_nr; i++)
1000                         git_config_set_multivar_in_file(opts_file,
1001                                                         "options.strategy-option",
1002                                                         opts->xopts[i], "^$", 0);
1003         }
1004 }
1005
1006 static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
1007 {
1008         struct commit_list *cur;
1009         int res;
1010
1011         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
1012         if (opts->allow_ff)
1013                 assert(!(opts->signoff || opts->no_commit ||
1014                                 opts->record_origin || opts->edit));
1015         if (read_and_refresh_cache(opts))
1016                 return -1;
1017
1018         for (cur = todo_list; cur; cur = cur->next) {
1019                 if (save_todo(cur, opts))
1020                         return -1;
1021                 res = do_pick_commit(cur->item, opts);
1022                 if (res)
1023                         return res;
1024         }
1025
1026         /*
1027          * Sequence of picks finished successfully; cleanup by
1028          * removing the .git/sequencer directory
1029          */
1030         remove_sequencer_state();
1031         return 0;
1032 }
1033
1034 static int continue_single_pick(void)
1035 {
1036         const char *argv[] = { "commit", NULL };
1037
1038         if (!file_exists(git_path_cherry_pick_head()) &&
1039             !file_exists(git_path_revert_head()))
1040                 return error(_("no cherry-pick or revert in progress"));
1041         return run_command_v_opt(argv, RUN_GIT_CMD);
1042 }
1043
1044 static int sequencer_continue(struct replay_opts *opts)
1045 {
1046         struct commit_list *todo_list = NULL;
1047
1048         if (!file_exists(git_path_todo_file()))
1049                 return continue_single_pick();
1050         if (read_populate_opts(&opts) ||
1051                         read_populate_todo(&todo_list, opts))
1052                 return -1;
1053
1054         /* Verify that the conflict has been resolved */
1055         if (file_exists(git_path_cherry_pick_head()) ||
1056             file_exists(git_path_revert_head())) {
1057                 int ret = continue_single_pick();
1058                 if (ret)
1059                         return ret;
1060         }
1061         if (index_differs_from("HEAD", 0))
1062                 return error_dirty_index(opts);
1063         todo_list = todo_list->next;
1064         return pick_commits(todo_list, opts);
1065 }
1066
1067 static int single_pick(struct commit *cmit, struct replay_opts *opts)
1068 {
1069         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
1070         return do_pick_commit(cmit, opts);
1071 }
1072
1073 int sequencer_pick_revisions(struct replay_opts *opts)
1074 {
1075         struct commit_list *todo_list = NULL;
1076         unsigned char sha1[20];
1077         int i;
1078
1079         if (opts->subcommand == REPLAY_NONE)
1080                 assert(opts->revs);
1081
1082         if (read_and_refresh_cache(opts))
1083                 return -1;
1084
1085         /*
1086          * Decide what to do depending on the arguments; a fresh
1087          * cherry-pick should be handled differently from an existing
1088          * one that is being continued
1089          */
1090         if (opts->subcommand == REPLAY_REMOVE_STATE) {
1091                 remove_sequencer_state();
1092                 return 0;
1093         }
1094         if (opts->subcommand == REPLAY_ROLLBACK)
1095                 return sequencer_rollback(opts);
1096         if (opts->subcommand == REPLAY_CONTINUE)
1097                 return sequencer_continue(opts);
1098
1099         for (i = 0; i < opts->revs->pending.nr; i++) {
1100                 unsigned char sha1[20];
1101                 const char *name = opts->revs->pending.objects[i].name;
1102
1103                 /* This happens when using --stdin. */
1104                 if (!strlen(name))
1105                         continue;
1106
1107                 if (!get_sha1(name, sha1)) {
1108                         if (!lookup_commit_reference_gently(sha1, 1)) {
1109                                 enum object_type type = sha1_object_info(sha1, NULL);
1110                                 return error(_("%s: can't cherry-pick a %s"),
1111                                         name, typename(type));
1112                         }
1113                 } else
1114                         return error(_("%s: bad revision"), name);
1115         }
1116
1117         /*
1118          * If we were called as "git cherry-pick <commit>", just
1119          * cherry-pick/revert it, set CHERRY_PICK_HEAD /
1120          * REVERT_HEAD, and don't touch the sequencer state.
1121          * This means it is possible to cherry-pick in the middle
1122          * of a cherry-pick sequence.
1123          */
1124         if (opts->revs->cmdline.nr == 1 &&
1125             opts->revs->cmdline.rev->whence == REV_CMD_REV &&
1126             opts->revs->no_walk &&
1127             !opts->revs->cmdline.rev->flags) {
1128                 struct commit *cmit;
1129                 if (prepare_revision_walk(opts->revs))
1130                         return error(_("revision walk setup failed"));
1131                 cmit = get_revision(opts->revs);
1132                 if (!cmit || get_revision(opts->revs))
1133                         return error("BUG: expected exactly one commit from walk");
1134                 return single_pick(cmit, opts);
1135         }
1136
1137         /*
1138          * Start a new cherry-pick/ revert sequence; but
1139          * first, make sure that an existing one isn't in
1140          * progress
1141          */
1142
1143         if (walk_revs_populate_todo(&todo_list, opts) ||
1144                         create_seq_dir() < 0)
1145                 return -1;
1146         if (get_sha1("HEAD", sha1) && (opts->action == REPLAY_REVERT))
1147                 return error(_("Can't revert as initial commit"));
1148         if (save_head(sha1_to_hex(sha1)))
1149                 return -1;
1150         save_opts(opts);
1151         return pick_commits(todo_list, opts);
1152 }
1153
1154 void append_signoff(struct strbuf *msgbuf, int ignore_footer, unsigned flag)
1155 {
1156         unsigned no_dup_sob = flag & APPEND_SIGNOFF_DEDUP;
1157         struct strbuf sob = STRBUF_INIT;
1158         int has_footer;
1159
1160         strbuf_addstr(&sob, sign_off_header);
1161         strbuf_addstr(&sob, fmt_name(getenv("GIT_COMMITTER_NAME"),
1162                                 getenv("GIT_COMMITTER_EMAIL")));
1163         strbuf_addch(&sob, '\n');
1164
1165         /*
1166          * If the whole message buffer is equal to the sob, pretend that we
1167          * found a conforming footer with a matching sob
1168          */
1169         if (msgbuf->len - ignore_footer == sob.len &&
1170             !strncmp(msgbuf->buf, sob.buf, sob.len))
1171                 has_footer = 3;
1172         else
1173                 has_footer = has_conforming_footer(msgbuf, &sob, ignore_footer);
1174
1175         if (!has_footer) {
1176                 const char *append_newlines = NULL;
1177                 size_t len = msgbuf->len - ignore_footer;
1178
1179                 if (!len) {
1180                         /*
1181                          * The buffer is completely empty.  Leave foom for
1182                          * the title and body to be filled in by the user.
1183                          */
1184                         append_newlines = "\n\n";
1185                 } else if (msgbuf->buf[len - 1] != '\n') {
1186                         /*
1187                          * Incomplete line.  Complete the line and add a
1188                          * blank one so that there is an empty line between
1189                          * the message body and the sob.
1190                          */
1191                         append_newlines = "\n\n";
1192                 } else if (len == 1) {
1193                         /*
1194                          * Buffer contains a single newline.  Add another
1195                          * so that we leave room for the title and body.
1196                          */
1197                         append_newlines = "\n";
1198                 } else if (msgbuf->buf[len - 2] != '\n') {
1199                         /*
1200                          * Buffer ends with a single newline.  Add another
1201                          * so that there is an empty line between the message
1202                          * body and the sob.
1203                          */
1204                         append_newlines = "\n";
1205                 } /* else, the buffer already ends with two newlines. */
1206
1207                 if (append_newlines)
1208                         strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0,
1209                                 append_newlines, strlen(append_newlines));
1210         }
1211
1212         if (has_footer != 3 && (!no_dup_sob || has_footer != 2))
1213                 strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0,
1214                                 sob.buf, sob.len);
1215
1216         strbuf_release(&sob);
1217 }