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 void 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,
 188                                                LOCK_DIE_ON_ERROR);
 189         if (write_in_full(msg_fd, msgbuf->buf, msgbuf->len) < 0)
 190                 die_errno(_("Could not write to %s"), filename);
 191         strbuf_release(msgbuf);
 192         if (commit_lock_file(&msg_file) < 0)
 193                 die(_("Error wrapping up %s"), filename);
 194 }
 195
 196 static struct tree *empty_tree(void)
 197 {
 198         return lookup_tree(EMPTY_TREE_SHA1_BIN);
 199 }
 200
 201 static int error_dirty_index(struct replay_opts *opts)
 202 {
 203         if (read_cache_unmerged())
 204                 return error_resolve_conflict(action_name(opts));
 205
 206         /* Different translation strings for cherry-pick and revert */
 207         if (opts->action == REPLAY_PICK)
 208                 error(_("Your local changes would be overwritten by cherry-pick."));
 209         else
 210                 error(_("Your local changes would be overwritten by revert."));
 211
 212         if (advice_commit_before_merge)
 213                 advise(_("Commit your changes or stash them to proceed."));
 214         return -1;
 215 }
 216
 217 static int fast_forward_to(const unsigned char *to, const unsigned char *from,
 218                         int unborn, struct replay_opts *opts)
 219 {
 220         struct ref_transaction *transaction;
 221         struct strbuf sb = STRBUF_INIT;
 222         struct strbuf err = STRBUF_INIT;
 223
 224         read_cache();
 225         if (checkout_fast_forward(from, to, 1))
 226                 exit(128); /* the callee should have complained already */
 227
 228         strbuf_addf(&sb, "%s: fast-forward", action_name(opts));
 229
 230         transaction = ref_transaction_begin(&err);
 231         if (!transaction ||
 232             ref_transaction_update(transaction, "HEAD",
 233                                    to, unborn ? null_sha1 : from,
 234                                    0, sb.buf, &err) ||
 235             ref_transaction_commit(transaction, &err)) {
 236                 ref_transaction_free(transaction);
 237                 error("%s", err.buf);
 238                 strbuf_release(&sb);
 239                 strbuf_release(&err);
 240                 return -1;
 241         }
 242
 243         strbuf_release(&sb);
 244         strbuf_release(&err);
 245         ref_transaction_free(transaction);
 246         return 0;
 247 }
 248
 249 void append_conflicts_hint(struct strbuf *msgbuf)
 250 {
 251         int i;
 252
 253         strbuf_addch(msgbuf, '\n');
 254         strbuf_commented_addf(msgbuf, "Conflicts:\n");
 255         for (i = 0; i < active_nr;) {
 256                 const struct cache_entry *ce = active_cache[i++];
 257                 if (ce_stage(ce)) {
 258                         strbuf_commented_addf(msgbuf, "\t%s\n", ce->name);
 259                         while (i < active_nr && !strcmp(ce->name,
 260                                                         active_cache[i]->name))
 261                                 i++;
 262                 }
 263         }
 264 }
 265
 266 static int do_recursive_merge(struct commit *base, struct commit *next,
 267                               const char *base_label, const char *next_label,
 268                               unsigned char *head, struct strbuf *msgbuf,
 269                               struct replay_opts *opts)
 270 {
 271         struct merge_options o;
 272         struct tree *result, *next_tree, *base_tree, *head_tree;
 273         int clean;
 274         const char **xopt;
 275         static struct lock_file index_lock;
 276
 277         hold_locked_index(&index_lock, 1);
 278
 279         read_cache();
 280
 281         init_merge_options(&o);
 282         o.ancestor = base ? base_label : "(empty tree)";
 283         o.branch1 = "HEAD";
 284         o.branch2 = next ? next_label : "(empty tree)";
 285
 286         head_tree = parse_tree_indirect(head);
 287         next_tree = next ? next->tree : empty_tree();
 288         base_tree = base ? base->tree : empty_tree();
 289
 290         for (xopt = opts->xopts; xopt != opts->xopts + opts->xopts_nr; xopt++)
 291                 parse_merge_opt(&o, *xopt);
 292
 293         clean = merge_trees(&o,
 294                             head_tree,
 295                             next_tree, base_tree, &result);
 296
 297         if (active_cache_changed &&
 298             write_locked_index(&the_index, &index_lock, COMMIT_LOCK))
 299                 /* TRANSLATORS: %s will be "revert" or "cherry-pick" */
 300                 die(_("%s: Unable to write new index file"), action_name(opts));
 301         rollback_lock_file(&index_lock);
 302
 303         if (opts->signoff)
 304                 append_signoff(msgbuf, 0, 0);
 305
 306         if (!clean)
 307                 append_conflicts_hint(msgbuf);
 308
 309         return !clean;
 310 }
 311
 312 static int is_index_unchanged(void)
 313 {
 314         unsigned char head_sha1[20];
 315         struct commit *head_commit;
 316
 317         if (!resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, head_sha1, NULL))
 318                 return error(_("Could not resolve HEAD commit\n"));
 319
 320         head_commit = lookup_commit(head_sha1);
 321
 322         /*
 323          * If head_commit is NULL, check_commit, called from
 324          * lookup_commit, would have indicated that head_commit is not
 325          * a commit object already.  parse_commit() will return failure
 326          * without further complaints in such a case.  Otherwise, if
 327          * the commit is invalid, parse_commit() will complain.  So
 328          * there is nothing for us to say here.  Just return failure.
 329          */
 330         if (parse_commit(head_commit))
 331                 return -1;
 332
 333         if (!active_cache_tree)
 334                 active_cache_tree = cache_tree();
 335
 336         if (!cache_tree_fully_valid(active_cache_tree))
 337                 if (cache_tree_update(&the_index, 0))
 338                         return error(_("Unable to update cache tree\n"));
 339
 340         return !hashcmp(active_cache_tree->sha1, head_commit->tree->object.oid.hash);
 341 }
 342
 343 /*
 344  * If we are cherry-pick, and if the merge did not result in
 345  * hand-editing, we will hit this commit and inherit the original
 346  * author date and name.
 347  * If we are revert, or if our cherry-pick results in a hand merge,
 348  * we had better say that the current user is responsible for that.
 349  */
 350 static int run_git_commit(const char *defmsg, struct replay_opts *opts,
 351                           int allow_empty)
 352 {
 353         struct argv_array array;
 354         int rc;
 355         const char *value;
 356
 357         argv_array_init(&array);
 358         argv_array_push(&array, "commit");
 359         argv_array_push(&array, "-n");
 360
 361         if (opts->gpg_sign)
 362                 argv_array_pushf(&array, "-S%s", opts->gpg_sign);
 363         if (opts->signoff)
 364                 argv_array_push(&array, "-s");
 365         if (!opts->edit) {
 366                 argv_array_push(&array, "-F");
 367                 argv_array_push(&array, defmsg);
 368                 if (!opts->signoff &&
 369                     !opts->record_origin &&
 370                     git_config_get_value("commit.cleanup", &value))
 371                         argv_array_push(&array, "--cleanup=verbatim");
 372         }
 373
 374         if (allow_empty)
 375                 argv_array_push(&array, "--allow-empty");
 376
 377         if (opts->allow_empty_message)
 378                 argv_array_push(&array, "--allow-empty-message");
 379
 380         rc = run_command_v_opt(array.argv, RUN_GIT_CMD);
 381         argv_array_clear(&array);
 382         return rc;
 383 }
 384
 385 static int is_original_commit_empty(struct commit *commit)
 386 {
 387         const unsigned char *ptree_sha1;
 388
 389         if (parse_commit(commit))
 390                 return error(_("Could not parse commit %s\n"),
 391                              oid_to_hex(&commit->object.oid));
 392         if (commit->parents) {
 393                 struct commit *parent = commit->parents->item;
 394                 if (parse_commit(parent))
 395                         return error(_("Could not parse parent commit %s\n"),
 396                                 oid_to_hex(&parent->object.oid));
 397                 ptree_sha1 = parent->tree->object.oid.hash;
 398         } else {
 399                 ptree_sha1 = EMPTY_TREE_SHA1_BIN; /* commit is root */
 400         }
 401
 402         return !hashcmp(ptree_sha1, commit->tree->object.oid.hash);
 403 }
 404
 405 /*
 406  * Do we run "git commit" with "--allow-empty"?
 407  */
 408 static int allow_empty(struct replay_opts *opts, struct commit *commit)
 409 {
 410         int index_unchanged, empty_commit;
 411
 412         /*
 413          * Three cases:
 414          *
 415          * (1) we do not allow empty at all and error out.
 416          *
 417          * (2) we allow ones that were initially empty, but
 418          * forbid the ones that become empty;
 419          *
 420          * (3) we allow both.
 421          */
 422         if (!opts->allow_empty)
 423                 return 0; /* let "git commit" barf as necessary */
 424
 425         index_unchanged = is_index_unchanged();
 426         if (index_unchanged < 0)
 427                 return index_unchanged;
 428         if (!index_unchanged)
 429                 return 0; /* we do not have to say --allow-empty */
 430
 431         if (opts->keep_redundant_commits)
 432                 return 1;
 433
 434         empty_commit = is_original_commit_empty(commit);
 435         if (empty_commit < 0)
 436                 return empty_commit;
 437         if (!empty_commit)
 438                 return 0;
 439         else
 440                 return 1;
 441 }
 442
 443 static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
 444 {
 445         unsigned char head[20];
 446         struct commit *base, *next, *parent;
 447         const char *base_label, *next_label;
 448         struct commit_message msg = { NULL, NULL, NULL, NULL };
 449         struct strbuf msgbuf = STRBUF_INIT;
 450         int res, unborn = 0, allow;
 451
 452         if (opts->no_commit) {
 453                 /*
 454                  * We do not intend to commit immediately.  We just want to
 455                  * merge the differences in, so let's compute the tree
 456                  * that represents the "current" state for merge-recursive
 457                  * to work on.
 458                  */
 459                 if (write_cache_as_tree(head, 0, NULL))
 460                         die (_("Your index file is unmerged."));
 461         } else {
 462                 unborn = get_sha1("HEAD", head);
 463                 if (unborn)
 464                         hashcpy(head, EMPTY_TREE_SHA1_BIN);
 465                 if (index_differs_from(unborn ? EMPTY_TREE_SHA1_HEX : "HEAD", 0))
 466                         return error_dirty_index(opts);
 467         }
 468         discard_cache();
 469
 470         if (!commit->parents) {
 471                 parent = NULL;
 472         }
 473         else if (commit->parents->next) {
 474                 /* Reverting or cherry-picking a merge commit */
 475                 int cnt;
 476                 struct commit_list *p;
 477
 478                 if (!opts->mainline)
 479                         return error(_("Commit %s is a merge but no -m option was given."),
 480                                 oid_to_hex(&commit->object.oid));
 481
 482                 for (cnt = 1, p = commit->parents;
 483                      cnt != opts->mainline && p;
 484                      cnt++)
 485                         p = p->next;
 486                 if (cnt != opts->mainline || !p)
 487                         return error(_("Commit %s does not have parent %d"),
 488                                 oid_to_hex(&commit->object.oid), opts->mainline);
 489                 parent = p->item;
 490         } else if (0 < opts->mainline)
 491                 return error(_("Mainline was specified but commit %s is not a merge."),
 492                         oid_to_hex(&commit->object.oid));
 493         else
 494                 parent = commit->parents->item;
 495
 496         if (opts->allow_ff &&
 497             ((parent && !hashcmp(parent->object.oid.hash, head)) ||
 498              (!parent && unborn)))
 499                 return fast_forward_to(commit->object.oid.hash, head, unborn, opts);
 500
 501         if (parent && parse_commit(parent) < 0)
 502                 /* TRANSLATORS: The first %s will be "revert" or
 503                    "cherry-pick", the second %s a SHA1 */
 504                 return error(_("%s: cannot parse parent commit %s"),
 505                         action_name(opts), oid_to_hex(&parent->object.oid));
 506
 507         if (get_message(commit, &msg) != 0)
 508                 return error(_("Cannot get commit message for %s"),
 509                         oid_to_hex(&commit->object.oid));
 510
 511         /*
 512          * "commit" is an existing commit.  We would want to apply
 513          * the difference it introduces since its first parent "prev"
 514          * on top of the current HEAD if we are cherry-pick.  Or the
 515          * reverse of it if we are revert.
 516          */
 517
 518         if (opts->action == REPLAY_REVERT) {
 519                 base = commit;
 520                 base_label = msg.label;
 521                 next = parent;
 522                 next_label = msg.parent_label;
 523                 strbuf_addstr(&msgbuf, "Revert \"");
 524                 strbuf_addstr(&msgbuf, msg.subject);
 525                 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
 526                 strbuf_addstr(&msgbuf, oid_to_hex(&commit->object.oid));
 527
 528                 if (commit->parents && commit->parents->next) {
 529                         strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
 530                         strbuf_addstr(&msgbuf, oid_to_hex(&parent->object.oid));
 531                 }
 532                 strbuf_addstr(&msgbuf, ".\n");
 533         } else {
 534                 const char *p;
 535
 536                 base = parent;
 537                 base_label = msg.parent_label;
 538                 next = commit;
 539                 next_label = msg.label;
 540
 541                 /*
 542                  * Append the commit log message to msgbuf; it starts
 543                  * after the tree, parent, author, committer
 544                  * information followed by "\n\n".
 545                  */
 546                 p = strstr(msg.message, "\n\n");
 547                 if (p)
 548                         strbuf_addstr(&msgbuf, skip_blank_lines(p + 2));
 549
 550                 if (opts->record_origin) {
 551                         if (!has_conforming_footer(&msgbuf, NULL, 0))
 552                                 strbuf_addch(&msgbuf, '\n');
 553                         strbuf_addstr(&msgbuf, cherry_picked_prefix);
 554                         strbuf_addstr(&msgbuf, oid_to_hex(&commit->object.oid));
 555                         strbuf_addstr(&msgbuf, ")\n");
 556                 }
 557         }
 558
 559         if (!opts->strategy || !strcmp(opts->strategy, "recursive") || opts->action == REPLAY_REVERT) {
 560                 res = do_recursive_merge(base, next, base_label, next_label,
 561                                          head, &msgbuf, opts);
 562                 write_message(&msgbuf, git_path_merge_msg());
 563         } else {
 564                 struct commit_list *common = NULL;
 565                 struct commit_list *remotes = NULL;
 566
 567                 write_message(&msgbuf, git_path_merge_msg());
 568
 569                 commit_list_insert(base, &common);
 570                 commit_list_insert(next, &remotes);
 571                 res = try_merge_command(opts->strategy, opts->xopts_nr, opts->xopts,
 572                                         common, sha1_to_hex(head), remotes);
 573                 free_commit_list(common);
 574                 free_commit_list(remotes);
 575         }
 576
 577         /*
 578          * If the merge was clean or if it failed due to conflict, we write
 579          * CHERRY_PICK_HEAD for the subsequent invocation of commit to use.
 580          * However, if the merge did not even start, then we don't want to
 581          * write it at all.
 582          */
 583         if (opts->action == REPLAY_PICK && !opts->no_commit && (res == 0 || res == 1))
 584                 update_ref(NULL, "CHERRY_PICK_HEAD", commit->object.oid.hash, NULL,
 585                            REF_NODEREF, UPDATE_REFS_DIE_ON_ERR);
 586         if (opts->action == REPLAY_REVERT && ((opts->no_commit && res == 0) || res == 1))
 587                 update_ref(NULL, "REVERT_HEAD", commit->object.oid.hash, NULL,
 588                            REF_NODEREF, UPDATE_REFS_DIE_ON_ERR);
 589
 590         if (res) {
 591                 error(opts->action == REPLAY_REVERT
 592                       ? _("could not revert %s... %s")
 593                       : _("could not apply %s... %s"),
 594                       find_unique_abbrev(commit->object.oid.hash, DEFAULT_ABBREV),
 595                       msg.subject);
 596                 print_advice(res == 1, opts);
 597                 rerere(opts->allow_rerere_auto);
 598                 goto leave;
 599         }
 600
 601         allow = allow_empty(opts, commit);
 602         if (allow < 0) {
 603                 res = allow;
 604                 goto leave;
 605         }
 606         if (!opts->no_commit)
 607                 res = run_git_commit(git_path_merge_msg(), opts, allow);
 608
 609 leave:
 610         free_message(commit, &msg);
 611
 612         return res;
 613 }
 614
 615 static void prepare_revs(struct replay_opts *opts)
 616 {
 617         /*
 618          * picking (but not reverting) ranges (but not individual revisions)
 619          * should be done in reverse
 620          */
 621         if (opts->action == REPLAY_PICK && !opts->revs->no_walk)
 622                 opts->revs->reverse ^= 1;
 623
 624         if (prepare_revision_walk(opts->revs))
 625                 die(_("revision walk setup failed"));
 626
 627         if (!opts->revs->commits)
 628                 die(_("empty commit set passed"));
 629 }
 630
 631 static void read_and_refresh_cache(struct replay_opts *opts)
 632 {
 633         static struct lock_file index_lock;
 634         int index_fd = hold_locked_index(&index_lock, 0);
 635         if (read_index_preload(&the_index, NULL) < 0)
 636                 die(_("git %s: failed to read the index"), action_name(opts));
 637         refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
 638         if (the_index.cache_changed && index_fd >= 0) {
 639                 if (write_locked_index(&the_index, &index_lock, COMMIT_LOCK))
 640                         die(_("git %s: failed to refresh the index"), action_name(opts));
 641         }
 642         rollback_lock_file(&index_lock);
 643 }
 644
 645 static int format_todo(struct strbuf *buf, struct commit_list *todo_list,
 646                 struct replay_opts *opts)
 647 {
 648         struct commit_list *cur = NULL;
 649         const char *sha1_abbrev = NULL;
 650         const char *action_str = opts->action == REPLAY_REVERT ? "revert" : "pick";
 651         const char *subject;
 652         int subject_len;
 653
 654         for (cur = todo_list; cur; cur = cur->next) {
 655                 const char *commit_buffer = get_commit_buffer(cur->item, NULL);
 656                 sha1_abbrev = find_unique_abbrev(cur->item->object.oid.hash, DEFAULT_ABBREV);
 657                 subject_len = find_commit_subject(commit_buffer, &subject);
 658                 strbuf_addf(buf, "%s %s %.*s\n", action_str, sha1_abbrev,
 659                         subject_len, subject);
 660                 unuse_commit_buffer(cur->item, commit_buffer);
 661         }
 662         return 0;
 663 }
 664
 665 static struct commit *parse_insn_line(char *bol, char *eol, struct replay_opts *opts)
 666 {
 667         unsigned char commit_sha1[20];
 668         enum replay_action action;
 669         char *end_of_object_name;
 670         int saved, status, padding;
 671
 672         if (starts_with(bol, "pick")) {
 673                 action = REPLAY_PICK;
 674                 bol += strlen("pick");
 675         } else if (starts_with(bol, "revert")) {
 676                 action = REPLAY_REVERT;
 677                 bol += strlen("revert");
 678         } else
 679                 return NULL;
 680
 681         /* Eat up extra spaces/ tabs before object name */
 682         padding = strspn(bol, " \t");
 683         if (!padding)
 684                 return NULL;
 685         bol += padding;
 686
 687         end_of_object_name = bol + strcspn(bol, " \t\n");
 688         saved = *end_of_object_name;
 689         *end_of_object_name = '\0';
 690         status = get_sha1(bol, commit_sha1);
 691         *end_of_object_name = saved;
 692
 693         /*
 694          * Verify that the action matches up with the one in
 695          * opts; we don't support arbitrary instructions
 696          */
 697         if (action != opts->action) {
 698                 const char *action_str;
 699                 action_str = action == REPLAY_REVERT ? "revert" : "cherry-pick";
 700                 error(_("Cannot %s during a %s"), action_str, action_name(opts));
 701                 return NULL;
 702         }
 703
 704         if (status < 0)
 705                 return NULL;
 706
 707         return lookup_commit_reference(commit_sha1);
 708 }
 709
 710 static int parse_insn_buffer(char *buf, struct commit_list **todo_list,
 711                         struct replay_opts *opts)
 712 {
 713         struct commit_list **next = todo_list;
 714         struct commit *commit;
 715         char *p = buf;
 716         int i;
 717
 718         for (i = 1; *p; i++) {
 719                 char *eol = strchrnul(p, '\n');
 720                 commit = parse_insn_line(p, eol, opts);
 721                 if (!commit)
 722                         return error(_("Could not parse line %d."), i);
 723                 next = commit_list_append(commit, next);
 724                 p = *eol ? eol + 1 : eol;
 725         }
 726         if (!*todo_list)
 727                 return error(_("No commits parsed."));
 728         return 0;
 729 }
 730
 731 static void read_populate_todo(struct commit_list **todo_list,
 732                         struct replay_opts *opts)
 733 {
 734         struct strbuf buf = STRBUF_INIT;
 735         int fd, res;
 736
 737         fd = open(git_path_todo_file(), O_RDONLY);
 738         if (fd < 0)
 739                 die_errno(_("Could not open %s"), git_path_todo_file());
 740         if (strbuf_read(&buf, fd, 0) < 0) {
 741                 close(fd);
 742                 strbuf_release(&buf);
 743                 die(_("Could not read %s."), git_path_todo_file());
 744         }
 745         close(fd);
 746
 747         res = parse_insn_buffer(buf.buf, todo_list, opts);
 748         strbuf_release(&buf);
 749         if (res)
 750                 die(_("Unusable instruction sheet: %s"), git_path_todo_file());
 751 }
 752
 753 static int populate_opts_cb(const char *key, const char *value, void *data)
 754 {
 755         struct replay_opts *opts = data;
 756         int error_flag = 1;
 757
 758         if (!value)
 759                 error_flag = 0;
 760         else if (!strcmp(key, "options.no-commit"))
 761                 opts->no_commit = git_config_bool_or_int(key, value, &error_flag);
 762         else if (!strcmp(key, "options.edit"))
 763                 opts->edit = git_config_bool_or_int(key, value, &error_flag);
 764         else if (!strcmp(key, "options.signoff"))
 765                 opts->signoff = git_config_bool_or_int(key, value, &error_flag);
 766         else if (!strcmp(key, "options.record-origin"))
 767                 opts->record_origin = git_config_bool_or_int(key, value, &error_flag);
 768         else if (!strcmp(key, "options.allow-ff"))
 769                 opts->allow_ff = git_config_bool_or_int(key, value, &error_flag);
 770         else if (!strcmp(key, "options.mainline"))
 771                 opts->mainline = git_config_int(key, value);
 772         else if (!strcmp(key, "options.strategy"))
 773                 git_config_string(&opts->strategy, key, value);
 774         else if (!strcmp(key, "options.gpg-sign"))
 775                 git_config_string(&opts->gpg_sign, key, value);
 776         else if (!strcmp(key, "options.strategy-option")) {
 777                 ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
 778                 opts->xopts[opts->xopts_nr++] = xstrdup(value);
 779         } else
 780                 return error(_("Invalid key: %s"), key);
 781
 782         if (!error_flag)
 783                 return error(_("Invalid value for %s: %s"), key, value);
 784
 785         return 0;
 786 }
 787
 788 static void read_populate_opts(struct replay_opts **opts_ptr)
 789 {
 790         if (!file_exists(git_path_opts_file()))
 791                 return;
 792         if (git_config_from_file(populate_opts_cb, git_path_opts_file(), *opts_ptr) < 0)
 793                 die(_("Malformed options sheet: %s"), git_path_opts_file());
 794 }
 795
 796 static void walk_revs_populate_todo(struct commit_list **todo_list,
 797                                 struct replay_opts *opts)
 798 {
 799         struct commit *commit;
 800         struct commit_list **next;
 801
 802         prepare_revs(opts);
 803
 804         next = todo_list;
 805         while ((commit = get_revision(opts->revs)))
 806                 next = commit_list_append(commit, next);
 807 }
 808
 809 static int create_seq_dir(void)
 810 {
 811         if (file_exists(git_path_seq_dir())) {
 812                 error(_("a cherry-pick or revert is already in progress"));
 813                 advise(_("try \"git cherry-pick (--continue | --quit | --abort)\""));
 814                 return -1;
 815         }
 816         else if (mkdir(git_path_seq_dir(), 0777) < 0)
 817                 die_errno(_("Could not create sequencer directory %s"),
 818                           git_path_seq_dir());
 819         return 0;
 820 }
 821
 822 static void save_head(const char *head)
 823 {
 824         static struct lock_file head_lock;
 825         struct strbuf buf = STRBUF_INIT;
 826         int fd;
 827
 828         fd = hold_lock_file_for_update(&head_lock, git_path_head_file(), LOCK_DIE_ON_ERROR);
 829         strbuf_addf(&buf, "%s\n", head);
 830         if (write_in_full(fd, buf.buf, buf.len) < 0)
 831                 die_errno(_("Could not write to %s"), git_path_head_file());
 832         if (commit_lock_file(&head_lock) < 0)
 833                 die(_("Error wrapping up %s."), git_path_head_file());
 834 }
 835
 836 static int reset_for_rollback(const unsigned char *sha1)
 837 {
 838         const char *argv[4];    /* reset --merge <arg> + NULL */
 839         argv[0] = "reset";
 840         argv[1] = "--merge";
 841         argv[2] = sha1_to_hex(sha1);
 842         argv[3] = NULL;
 843         return run_command_v_opt(argv, RUN_GIT_CMD);
 844 }
 845
 846 static int rollback_single_pick(void)
 847 {
 848         unsigned char head_sha1[20];
 849
 850         if (!file_exists(git_path_cherry_pick_head()) &&
 851             !file_exists(git_path_revert_head()))
 852                 return error(_("no cherry-pick or revert in progress"));
 853         if (read_ref_full("HEAD", 0, head_sha1, NULL))
 854                 return error(_("cannot resolve HEAD"));
 855         if (is_null_sha1(head_sha1))
 856                 return error(_("cannot abort from a branch yet to be born"));
 857         return reset_for_rollback(head_sha1);
 858 }
 859
 860 static int sequencer_rollback(struct replay_opts *opts)
 861 {
 862         FILE *f;
 863         unsigned char sha1[20];
 864         struct strbuf buf = STRBUF_INIT;
 865
 866         f = fopen(git_path_head_file(), "r");
 867         if (!f && errno == ENOENT) {
 868                 /*
 869                  * There is no multiple-cherry-pick in progress.
 870                  * If CHERRY_PICK_HEAD or REVERT_HEAD indicates
 871                  * a single-cherry-pick in progress, abort that.
 872                  */
 873                 return rollback_single_pick();
 874         }
 875         if (!f)
 876                 return error_errno(_("cannot open %s"), git_path_head_file());
 877         if (strbuf_getline_lf(&buf, f)) {
 878                 error(_("cannot read %s: %s"), git_path_head_file(),
 879                       ferror(f) ?  strerror(errno) : _("unexpected end of file"));
 880                 fclose(f);
 881                 goto fail;
 882         }
 883         fclose(f);
 884         if (get_sha1_hex(buf.buf, sha1) || buf.buf[40] != '\0') {
 885                 error(_("stored pre-cherry-pick HEAD file '%s' is corrupt"),
 886                         git_path_head_file());
 887                 goto fail;
 888         }
 889         if (is_null_sha1(sha1)) {
 890                 error(_("cannot abort from a branch yet to be born"));
 891                 goto fail;
 892         }
 893         if (reset_for_rollback(sha1))
 894                 goto fail;
 895         remove_sequencer_state();
 896         strbuf_release(&buf);
 897         return 0;
 898 fail:
 899         strbuf_release(&buf);
 900         return -1;
 901 }
 902
 903 static void save_todo(struct commit_list *todo_list, struct replay_opts *opts)
 904 {
 905         static struct lock_file todo_lock;
 906         struct strbuf buf = STRBUF_INIT;
 907         int fd;
 908
 909         fd = hold_lock_file_for_update(&todo_lock, git_path_todo_file(), LOCK_DIE_ON_ERROR);
 910         if (format_todo(&buf, todo_list, opts) < 0)
 911                 die(_("Could not format %s."), git_path_todo_file());
 912         if (write_in_full(fd, buf.buf, buf.len) < 0) {
 913                 strbuf_release(&buf);
 914                 die_errno(_("Could not write to %s"), git_path_todo_file());
 915         }
 916         if (commit_lock_file(&todo_lock) < 0) {
 917                 strbuf_release(&buf);
 918                 die(_("Error wrapping up %s."), git_path_todo_file());
 919         }
 920         strbuf_release(&buf);
 921 }
 922
 923 static void save_opts(struct replay_opts *opts)
 924 {
 925         const char *opts_file = git_path_opts_file();
 926
 927         if (opts->no_commit)
 928                 git_config_set_in_file(opts_file, "options.no-commit", "true");
 929         if (opts->edit)
 930                 git_config_set_in_file(opts_file, "options.edit", "true");
 931         if (opts->signoff)
 932                 git_config_set_in_file(opts_file, "options.signoff", "true");
 933         if (opts->record_origin)
 934                 git_config_set_in_file(opts_file, "options.record-origin", "true");
 935         if (opts->allow_ff)
 936                 git_config_set_in_file(opts_file, "options.allow-ff", "true");
 937         if (opts->mainline) {
 938                 struct strbuf buf = STRBUF_INIT;
 939                 strbuf_addf(&buf, "%d", opts->mainline);
 940                 git_config_set_in_file(opts_file, "options.mainline", buf.buf);
 941                 strbuf_release(&buf);
 942         }
 943         if (opts->strategy)
 944                 git_config_set_in_file(opts_file, "options.strategy", opts->strategy);
 945         if (opts->gpg_sign)
 946                 git_config_set_in_file(opts_file, "options.gpg-sign", opts->gpg_sign);
 947         if (opts->xopts) {
 948                 int i;
 949                 for (i = 0; i < opts->xopts_nr; i++)
 950                         git_config_set_multivar_in_file(opts_file,
 951                                                         "options.strategy-option",
 952                                                         opts->xopts[i], "^$", 0);
 953         }
 954 }
 955
 956 static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
 957 {
 958         struct commit_list *cur;
 959         int res;
 960
 961         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
 962         if (opts->allow_ff)
 963                 assert(!(opts->signoff || opts->no_commit ||
 964                                 opts->record_origin || opts->edit));
 965         read_and_refresh_cache(opts);
 966
 967         for (cur = todo_list; cur; cur = cur->next) {
 968                 save_todo(cur, opts);
 969                 res = do_pick_commit(cur->item, opts);
 970                 if (res)
 971                         return res;
 972         }
 973
 974         /*
 975          * Sequence of picks finished successfully; cleanup by
 976          * removing the .git/sequencer directory
 977          */
 978         remove_sequencer_state();
 979         return 0;
 980 }
 981
 982 static int continue_single_pick(void)
 983 {
 984         const char *argv[] = { "commit", NULL };
 985
 986         if (!file_exists(git_path_cherry_pick_head()) &&
 987             !file_exists(git_path_revert_head()))
 988                 return error(_("no cherry-pick or revert in progress"));
 989         return run_command_v_opt(argv, RUN_GIT_CMD);
 990 }
 991
 992 static int sequencer_continue(struct replay_opts *opts)
 993 {
 994         struct commit_list *todo_list = NULL;
 995
 996         if (!file_exists(git_path_todo_file()))
 997                 return continue_single_pick();
 998         read_populate_opts(&opts);
 999         read_populate_todo(&todo_list, opts);
1000
1001         /* Verify that the conflict has been resolved */
1002         if (file_exists(git_path_cherry_pick_head()) ||
1003             file_exists(git_path_revert_head())) {
1004                 int ret = continue_single_pick();
1005                 if (ret)
1006                         return ret;
1007         }
1008         if (index_differs_from("HEAD", 0))
1009                 return error_dirty_index(opts);
1010         todo_list = todo_list->next;
1011         return pick_commits(todo_list, opts);
1012 }
1013
1014 static int single_pick(struct commit *cmit, struct replay_opts *opts)
1015 {
1016         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
1017         return do_pick_commit(cmit, opts);
1018 }
1019
1020 int sequencer_pick_revisions(struct replay_opts *opts)
1021 {
1022         struct commit_list *todo_list = NULL;
1023         unsigned char sha1[20];
1024         int i;
1025
1026         if (opts->subcommand == REPLAY_NONE)
1027                 assert(opts->revs);
1028
1029         read_and_refresh_cache(opts);
1030
1031         /*
1032          * Decide what to do depending on the arguments; a fresh
1033          * cherry-pick should be handled differently from an existing
1034          * one that is being continued
1035          */
1036         if (opts->subcommand == REPLAY_REMOVE_STATE) {
1037                 remove_sequencer_state();
1038                 return 0;
1039         }
1040         if (opts->subcommand == REPLAY_ROLLBACK)
1041                 return sequencer_rollback(opts);
1042         if (opts->subcommand == REPLAY_CONTINUE)
1043                 return sequencer_continue(opts);
1044
1045         for (i = 0; i < opts->revs->pending.nr; i++) {
1046                 unsigned char sha1[20];
1047                 const char *name = opts->revs->pending.objects[i].name;
1048
1049                 /* This happens when using --stdin. */
1050                 if (!strlen(name))
1051                         continue;
1052
1053                 if (!get_sha1(name, sha1)) {
1054                         if (!lookup_commit_reference_gently(sha1, 1)) {
1055                                 enum object_type type = sha1_object_info(sha1, NULL);
1056                                 die(_("%s: can't cherry-pick a %s"), name, typename(type));
1057                         }
1058                 } else
1059                         die(_("%s: bad revision"), name);
1060         }
1061
1062         /*
1063          * If we were called as "git cherry-pick <commit>", just
1064          * cherry-pick/revert it, set CHERRY_PICK_HEAD /
1065          * REVERT_HEAD, and don't touch the sequencer state.
1066          * This means it is possible to cherry-pick in the middle
1067          * of a cherry-pick sequence.
1068          */
1069         if (opts->revs->cmdline.nr == 1 &&
1070             opts->revs->cmdline.rev->whence == REV_CMD_REV &&
1071             opts->revs->no_walk &&
1072             !opts->revs->cmdline.rev->flags) {
1073                 struct commit *cmit;
1074                 if (prepare_revision_walk(opts->revs))
1075                         die(_("revision walk setup failed"));
1076                 cmit = get_revision(opts->revs);
1077                 if (!cmit || get_revision(opts->revs))
1078                         die("BUG: expected exactly one commit from walk");
1079                 return single_pick(cmit, opts);
1080         }
1081
1082         /*
1083          * Start a new cherry-pick/ revert sequence; but
1084          * first, make sure that an existing one isn't in
1085          * progress
1086          */
1087
1088         walk_revs_populate_todo(&todo_list, opts);
1089         if (create_seq_dir() < 0)
1090                 return -1;
1091         if (get_sha1("HEAD", sha1) && (opts->action == REPLAY_REVERT))
1092                 return error(_("Can't revert as initial commit"));
1093         save_head(sha1_to_hex(sha1));
1094         save_opts(opts);
1095         return pick_commits(todo_list, opts);
1096 }
1097
1098 void append_signoff(struct strbuf *msgbuf, int ignore_footer, unsigned flag)
1099 {
1100         unsigned no_dup_sob = flag & APPEND_SIGNOFF_DEDUP;
1101         struct strbuf sob = STRBUF_INIT;
1102         int has_footer;
1103
1104         strbuf_addstr(&sob, sign_off_header);
1105         strbuf_addstr(&sob, fmt_name(getenv("GIT_COMMITTER_NAME"),
1106                                 getenv("GIT_COMMITTER_EMAIL")));
1107         strbuf_addch(&sob, '\n');
1108
1109         /*
1110          * If the whole message buffer is equal to the sob, pretend that we
1111          * found a conforming footer with a matching sob
1112          */
1113         if (msgbuf->len - ignore_footer == sob.len &&
1114             !strncmp(msgbuf->buf, sob.buf, sob.len))
1115                 has_footer = 3;
1116         else
1117                 has_footer = has_conforming_footer(msgbuf, &sob, ignore_footer);
1118
1119         if (!has_footer) {
1120                 const char *append_newlines = NULL;
1121                 size_t len = msgbuf->len - ignore_footer;
1122
1123                 if (!len) {
1124                         /*
1125                          * The buffer is completely empty.  Leave foom for
1126                          * the title and body to be filled in by the user.
1127                          */
1128                         append_newlines = "\n\n";
1129                 } else if (msgbuf->buf[len - 1] != '\n') {
1130                         /*
1131                          * Incomplete line.  Complete the line and add a
1132                          * blank one so that there is an empty line between
1133                          * the message body and the sob.
1134                          */
1135                         append_newlines = "\n\n";
1136                 } else if (len == 1) {
1137                         /*
1138                          * Buffer contains a single newline.  Add another
1139                          * so that we leave room for the title and body.
1140                          */
1141                         append_newlines = "\n";
1142                 } else if (msgbuf->buf[len - 2] != '\n') {
1143                         /*
1144                          * Buffer ends with a single newline.  Add another
1145                          * so that there is an empty line between the message
1146                          * body and the sob.
1147                          */
1148                         append_newlines = "\n";
1149                 } /* else, the buffer already ends with two newlines. */
1150
1151                 if (append_newlines)
1152                         strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0,
1153                                 append_newlines, strlen(append_newlines));
1154         }
1155
1156         if (has_footer != 3 && (!no_dup_sob || has_footer != 2))
1157                 strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0,
1158                                 sob.buf, sob.len);
1159
1160         strbuf_release(&sob);
1161 }