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 int is_rfc2822_line(const char *buf, int len)
  25 {
  26         int i;
  27
  28         for (i = 0; i < len; i++) {
  29                 int ch = buf[i];
  30                 if (ch == ':')
  31                         return 1;
  32                 if (!isalnum(ch) && ch != '-')
  33                         break;
  34         }
  35
  36         return 0;
  37 }
  38
  39 static int is_cherry_picked_from_line(const char *buf, int len)
  40 {
  41         /*
  42          * We only care that it looks roughly like (cherry picked from ...)
  43          */
  44         return len > strlen(cherry_picked_prefix) + 1 &&
  45                 starts_with(buf, cherry_picked_prefix) && buf[len - 1] == ')';
  46 }
  47
  48 /*
  49  * Returns 0 for non-conforming footer
  50  * Returns 1 for conforming footer
  51  * Returns 2 when sob exists within conforming footer
  52  * Returns 3 when sob exists within conforming footer as last entry
  53  */
  54 static int has_conforming_footer(struct strbuf *sb, struct strbuf *sob,
  55         int ignore_footer)
  56 {
  57         char prev;
  58         int i, k;
  59         int len = sb->len - ignore_footer;
  60         const char *buf = sb->buf;
  61         int found_sob = 0;
  62
  63         /* footer must end with newline */
  64         if (!len || buf[len - 1] != '\n')
  65                 return 0;
  66
  67         prev = '\0';
  68         for (i = len - 1; i > 0; i--) {
  69                 char ch = buf[i];
  70                 if (prev == '\n' && ch == '\n') /* paragraph break */
  71                         break;
  72                 prev = ch;
  73         }
  74
  75         /* require at least one blank line */
  76         if (prev != '\n' || buf[i] != '\n')
  77                 return 0;
  78
  79         /* advance to start of last paragraph */
  80         while (i < len - 1 && buf[i] == '\n')
  81                 i++;
  82
  83         for (; i < len; i = k) {
  84                 int found_rfc2822;
  85
  86                 for (k = i; k < len && buf[k] != '\n'; k++)
  87                         ; /* do nothing */
  88                 k++;
  89
  90                 found_rfc2822 = is_rfc2822_line(buf + i, k - i - 1);
  91                 if (found_rfc2822 && sob &&
  92                     !strncmp(buf + i, sob->buf, sob->len))
  93                         found_sob = k;
  94
  95                 if (!(found_rfc2822 ||
  96                       is_cherry_picked_from_line(buf + i, k - i - 1)))
  97                         return 0;
  98         }
  99         if (found_sob == i)
 100                 return 3;
 101         if (found_sob)
 102                 return 2;
 103         return 1;
 104 }
 105
 106 static void remove_sequencer_state(void)
 107 {
 108         struct strbuf seq_dir = STRBUF_INIT;
 109
 110         strbuf_addf(&seq_dir, "%s", git_path(SEQ_DIR));
 111         remove_dir_recursively(&seq_dir, 0);
 112         strbuf_release(&seq_dir);
 113 }
 114
 115 static const char *action_name(const struct replay_opts *opts)
 116 {
 117         return opts->action == REPLAY_REVERT ? "revert" : "cherry-pick";
 118 }
 119
 120 struct commit_message {
 121         char *parent_label;
 122         const char *label;
 123         const char *subject;
 124         const char *message;
 125 };
 126
 127 static int get_message(struct commit *commit, struct commit_message *out)
 128 {
 129         const char *abbrev, *subject;
 130         int abbrev_len, subject_len;
 131         char *q;
 132
 133         if (!git_commit_encoding)
 134                 git_commit_encoding = "UTF-8";
 135
 136         out->message = logmsg_reencode(commit, NULL, git_commit_encoding);
 137         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
 138         abbrev_len = strlen(abbrev);
 139
 140         subject_len = find_commit_subject(out->message, &subject);
 141
 142         out->parent_label = xmalloc(strlen("parent of ") + abbrev_len +
 143                               strlen("... ") + subject_len + 1);
 144         q = out->parent_label;
 145         q = mempcpy(q, "parent of ", strlen("parent of "));
 146         out->label = q;
 147         q = mempcpy(q, abbrev, abbrev_len);
 148         q = mempcpy(q, "... ", strlen("... "));
 149         out->subject = q;
 150         q = mempcpy(q, subject, subject_len);
 151         *q = '\0';
 152         return 0;
 153 }
 154
 155 static void free_message(struct commit *commit, struct commit_message *msg)
 156 {
 157         free(msg->parent_label);
 158         unuse_commit_buffer(commit, msg->message);
 159 }
 160
 161 static void write_cherry_pick_head(struct commit *commit, const char *pseudoref)
 162 {
 163         const char *filename;
 164         int fd;
 165         struct strbuf buf = STRBUF_INIT;
 166
 167         strbuf_addf(&buf, "%s\n", sha1_to_hex(commit->object.sha1));
 168
 169         filename = git_path("%s", pseudoref);
 170         fd = open(filename, O_WRONLY | O_CREAT, 0666);
 171         if (fd < 0)
 172                 die_errno(_("Could not open '%s' for writing"), filename);
 173         if (write_in_full(fd, buf.buf, buf.len) != buf.len || close(fd))
 174                 die_errno(_("Could not write to '%s'"), filename);
 175         strbuf_release(&buf);
 176 }
 177
 178 static void print_advice(int show_hint, struct replay_opts *opts)
 179 {
 180         char *msg = getenv("GIT_CHERRY_PICK_HELP");
 181
 182         if (msg) {
 183                 fprintf(stderr, "%s\n", msg);
 184                 /*
 185                  * A conflict has occurred but the porcelain
 186                  * (typically rebase --interactive) wants to take care
 187                  * of the commit itself so remove CHERRY_PICK_HEAD
 188                  */
 189                 unlink(git_path("CHERRY_PICK_HEAD"));
 190                 return;
 191         }
 192
 193         if (show_hint) {
 194                 if (opts->no_commit)
 195                         advise(_("after resolving the conflicts, mark the corrected paths\n"
 196                                  "with 'git add <paths>' or 'git rm <paths>'"));
 197                 else
 198                         advise(_("after resolving the conflicts, mark the corrected paths\n"
 199                                  "with 'git add <paths>' or 'git rm <paths>'\n"
 200                                  "and commit the result with 'git commit'"));
 201         }
 202 }
 203
 204 static void write_message(struct strbuf *msgbuf, const char *filename)
 205 {
 206         static struct lock_file msg_file;
 207
 208         int msg_fd = hold_lock_file_for_update(&msg_file, filename,
 209                                                LOCK_DIE_ON_ERROR);
 210         if (write_in_full(msg_fd, msgbuf->buf, msgbuf->len) < 0)
 211                 die_errno(_("Could not write to %s"), filename);
 212         strbuf_release(msgbuf);
 213         if (commit_lock_file(&msg_file) < 0)
 214                 die(_("Error wrapping up %s"), filename);
 215 }
 216
 217 static struct tree *empty_tree(void)
 218 {
 219         return lookup_tree(EMPTY_TREE_SHA1_BIN);
 220 }
 221
 222 static int error_dirty_index(struct replay_opts *opts)
 223 {
 224         if (read_cache_unmerged())
 225                 return error_resolve_conflict(action_name(opts));
 226
 227         /* Different translation strings for cherry-pick and revert */
 228         if (opts->action == REPLAY_PICK)
 229                 error(_("Your local changes would be overwritten by cherry-pick."));
 230         else
 231                 error(_("Your local changes would be overwritten by revert."));
 232
 233         if (advice_commit_before_merge)
 234                 advise(_("Commit your changes or stash them to proceed."));
 235         return -1;
 236 }
 237
 238 static int fast_forward_to(const unsigned char *to, const unsigned char *from,
 239                         int unborn, struct replay_opts *opts)
 240 {
 241         struct ref_transaction *transaction;
 242         struct strbuf sb = STRBUF_INIT;
 243         struct strbuf err = STRBUF_INIT;
 244
 245         read_cache();
 246         if (checkout_fast_forward(from, to, 1))
 247                 exit(128); /* the callee should have complained already */
 248
 249         strbuf_addf(&sb, "%s: fast-forward", action_name(opts));
 250
 251         transaction = ref_transaction_begin(&err);
 252         if (!transaction ||
 253             ref_transaction_update(transaction, "HEAD",
 254                                    to, unborn ? null_sha1 : from,
 255                                    0, sb.buf, &err) ||
 256             ref_transaction_commit(transaction, &err)) {
 257                 ref_transaction_free(transaction);
 258                 error("%s", err.buf);
 259                 strbuf_release(&sb);
 260                 strbuf_release(&err);
 261                 return -1;
 262         }
 263
 264         strbuf_release(&sb);
 265         strbuf_release(&err);
 266         ref_transaction_free(transaction);
 267         return 0;
 268 }
 269
 270 void append_conflicts_hint(struct strbuf *msgbuf)
 271 {
 272         int i;
 273
 274         strbuf_addch(msgbuf, '\n');
 275         strbuf_commented_addf(msgbuf, "Conflicts:\n");
 276         for (i = 0; i < active_nr;) {
 277                 const struct cache_entry *ce = active_cache[i++];
 278                 if (ce_stage(ce)) {
 279                         strbuf_commented_addf(msgbuf, "\t%s\n", ce->name);
 280                         while (i < active_nr && !strcmp(ce->name,
 281                                                         active_cache[i]->name))
 282                                 i++;
 283                 }
 284         }
 285 }
 286
 287 static int do_recursive_merge(struct commit *base, struct commit *next,
 288                               const char *base_label, const char *next_label,
 289                               unsigned char *head, struct strbuf *msgbuf,
 290                               struct replay_opts *opts)
 291 {
 292         struct merge_options o;
 293         struct tree *result, *next_tree, *base_tree, *head_tree;
 294         int clean;
 295         const char **xopt;
 296         static struct lock_file index_lock;
 297
 298         hold_locked_index(&index_lock, 1);
 299
 300         read_cache();
 301
 302         init_merge_options(&o);
 303         o.ancestor = base ? base_label : "(empty tree)";
 304         o.branch1 = "HEAD";
 305         o.branch2 = next ? next_label : "(empty tree)";
 306
 307         head_tree = parse_tree_indirect(head);
 308         next_tree = next ? next->tree : empty_tree();
 309         base_tree = base ? base->tree : empty_tree();
 310
 311         for (xopt = opts->xopts; xopt != opts->xopts + opts->xopts_nr; xopt++)
 312                 parse_merge_opt(&o, *xopt);
 313
 314         clean = merge_trees(&o,
 315                             head_tree,
 316                             next_tree, base_tree, &result);
 317
 318         if (active_cache_changed &&
 319             write_locked_index(&the_index, &index_lock, COMMIT_LOCK))
 320                 /* TRANSLATORS: %s will be "revert" or "cherry-pick" */
 321                 die(_("%s: Unable to write new index file"), action_name(opts));
 322         rollback_lock_file(&index_lock);
 323
 324         if (opts->signoff)
 325                 append_signoff(msgbuf, 0, 0);
 326
 327         if (!clean)
 328                 append_conflicts_hint(msgbuf);
 329
 330         return !clean;
 331 }
 332
 333 static int is_index_unchanged(void)
 334 {
 335         unsigned char head_sha1[20];
 336         struct commit *head_commit;
 337
 338         if (!resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, head_sha1, NULL))
 339                 return error(_("Could not resolve HEAD commit\n"));
 340
 341         head_commit = lookup_commit(head_sha1);
 342
 343         /*
 344          * If head_commit is NULL, check_commit, called from
 345          * lookup_commit, would have indicated that head_commit is not
 346          * a commit object already.  parse_commit() will return failure
 347          * without further complaints in such a case.  Otherwise, if
 348          * the commit is invalid, parse_commit() will complain.  So
 349          * there is nothing for us to say here.  Just return failure.
 350          */
 351         if (parse_commit(head_commit))
 352                 return -1;
 353
 354         if (!active_cache_tree)
 355                 active_cache_tree = cache_tree();
 356
 357         if (!cache_tree_fully_valid(active_cache_tree))
 358                 if (cache_tree_update(&the_index, 0))
 359                         return error(_("Unable to update cache tree\n"));
 360
 361         return !hashcmp(active_cache_tree->sha1, head_commit->tree->object.sha1);
 362 }
 363
 364 /*
 365  * If we are cherry-pick, and if the merge did not result in
 366  * hand-editing, we will hit this commit and inherit the original
 367  * author date and name.
 368  * If we are revert, or if our cherry-pick results in a hand merge,
 369  * we had better say that the current user is responsible for that.
 370  */
 371 static int run_git_commit(const char *defmsg, struct replay_opts *opts,
 372                           int allow_empty)
 373 {
 374         struct argv_array array;
 375         int rc;
 376         const char *value;
 377
 378         argv_array_init(&array);
 379         argv_array_push(&array, "commit");
 380         argv_array_push(&array, "-n");
 381
 382         if (opts->gpg_sign)
 383                 argv_array_pushf(&array, "-S%s", opts->gpg_sign);
 384         if (opts->signoff)
 385                 argv_array_push(&array, "-s");
 386         if (!opts->edit) {
 387                 argv_array_push(&array, "-F");
 388                 argv_array_push(&array, defmsg);
 389                 if (!opts->signoff &&
 390                     !opts->record_origin &&
 391                     git_config_get_value("commit.cleanup", &value))
 392                         argv_array_push(&array, "--cleanup=verbatim");
 393         }
 394
 395         if (allow_empty)
 396                 argv_array_push(&array, "--allow-empty");
 397
 398         if (opts->allow_empty_message)
 399                 argv_array_push(&array, "--allow-empty-message");
 400
 401         rc = run_command_v_opt(array.argv, RUN_GIT_CMD);
 402         argv_array_clear(&array);
 403         return rc;
 404 }
 405
 406 static int is_original_commit_empty(struct commit *commit)
 407 {
 408         const unsigned char *ptree_sha1;
 409
 410         if (parse_commit(commit))
 411                 return error(_("Could not parse commit %s\n"),
 412                              sha1_to_hex(commit->object.sha1));
 413         if (commit->parents) {
 414                 struct commit *parent = commit->parents->item;
 415                 if (parse_commit(parent))
 416                         return error(_("Could not parse parent commit %s\n"),
 417                                 sha1_to_hex(parent->object.sha1));
 418                 ptree_sha1 = parent->tree->object.sha1;
 419         } else {
 420                 ptree_sha1 = EMPTY_TREE_SHA1_BIN; /* commit is root */
 421         }
 422
 423         return !hashcmp(ptree_sha1, commit->tree->object.sha1);
 424 }
 425
 426 /*
 427  * Do we run "git commit" with "--allow-empty"?
 428  */
 429 static int allow_empty(struct replay_opts *opts, struct commit *commit)
 430 {
 431         int index_unchanged, empty_commit;
 432
 433         /*
 434          * Three cases:
 435          *
 436          * (1) we do not allow empty at all and error out.
 437          *
 438          * (2) we allow ones that were initially empty, but
 439          * forbid the ones that become empty;
 440          *
 441          * (3) we allow both.
 442          */
 443         if (!opts->allow_empty)
 444                 return 0; /* let "git commit" barf as necessary */
 445
 446         index_unchanged = is_index_unchanged();
 447         if (index_unchanged < 0)
 448                 return index_unchanged;
 449         if (!index_unchanged)
 450                 return 0; /* we do not have to say --allow-empty */
 451
 452         if (opts->keep_redundant_commits)
 453                 return 1;
 454
 455         empty_commit = is_original_commit_empty(commit);
 456         if (empty_commit < 0)
 457                 return empty_commit;
 458         if (!empty_commit)
 459                 return 0;
 460         else
 461                 return 1;
 462 }
 463
 464 static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
 465 {
 466         unsigned char head[20];
 467         struct commit *base, *next, *parent;
 468         const char *base_label, *next_label;
 469         struct commit_message msg = { NULL, NULL, NULL, NULL };
 470         char *defmsg = NULL;
 471         struct strbuf msgbuf = STRBUF_INIT;
 472         int res, unborn = 0, allow;
 473
 474         if (opts->no_commit) {
 475                 /*
 476                  * We do not intend to commit immediately.  We just want to
 477                  * merge the differences in, so let's compute the tree
 478                  * that represents the "current" state for merge-recursive
 479                  * to work on.
 480                  */
 481                 if (write_cache_as_tree(head, 0, NULL))
 482                         die (_("Your index file is unmerged."));
 483         } else {
 484                 unborn = get_sha1("HEAD", head);
 485                 if (unborn)
 486                         hashcpy(head, EMPTY_TREE_SHA1_BIN);
 487                 if (index_differs_from(unborn ? EMPTY_TREE_SHA1_HEX : "HEAD", 0))
 488                         return error_dirty_index(opts);
 489         }
 490         discard_cache();
 491
 492         if (!commit->parents) {
 493                 parent = NULL;
 494         }
 495         else if (commit->parents->next) {
 496                 /* Reverting or cherry-picking a merge commit */
 497                 int cnt;
 498                 struct commit_list *p;
 499
 500                 if (!opts->mainline)
 501                         return error(_("Commit %s is a merge but no -m option was given."),
 502                                 sha1_to_hex(commit->object.sha1));
 503
 504                 for (cnt = 1, p = commit->parents;
 505                      cnt != opts->mainline && p;
 506                      cnt++)
 507                         p = p->next;
 508                 if (cnt != opts->mainline || !p)
 509                         return error(_("Commit %s does not have parent %d"),
 510                                 sha1_to_hex(commit->object.sha1), opts->mainline);
 511                 parent = p->item;
 512         } else if (0 < opts->mainline)
 513                 return error(_("Mainline was specified but commit %s is not a merge."),
 514                         sha1_to_hex(commit->object.sha1));
 515         else
 516                 parent = commit->parents->item;
 517
 518         if (opts->allow_ff &&
 519             ((parent && !hashcmp(parent->object.sha1, head)) ||
 520              (!parent && unborn)))
 521                 return fast_forward_to(commit->object.sha1, head, unborn, opts);
 522
 523         if (parent && parse_commit(parent) < 0)
 524                 /* TRANSLATORS: The first %s will be "revert" or
 525                    "cherry-pick", the second %s a SHA1 */
 526                 return error(_("%s: cannot parse parent commit %s"),
 527                         action_name(opts), sha1_to_hex(parent->object.sha1));
 528
 529         if (get_message(commit, &msg) != 0)
 530                 return error(_("Cannot get commit message for %s"),
 531                         sha1_to_hex(commit->object.sha1));
 532
 533         /*
 534          * "commit" is an existing commit.  We would want to apply
 535          * the difference it introduces since its first parent "prev"
 536          * on top of the current HEAD if we are cherry-pick.  Or the
 537          * reverse of it if we are revert.
 538          */
 539
 540         defmsg = git_pathdup("MERGE_MSG");
 541
 542         if (opts->action == REPLAY_REVERT) {
 543                 base = commit;
 544                 base_label = msg.label;
 545                 next = parent;
 546                 next_label = msg.parent_label;
 547                 strbuf_addstr(&msgbuf, "Revert \"");
 548                 strbuf_addstr(&msgbuf, msg.subject);
 549                 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
 550                 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 551
 552                 if (commit->parents && commit->parents->next) {
 553                         strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
 554                         strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
 555                 }
 556                 strbuf_addstr(&msgbuf, ".\n");
 557         } else {
 558                 const char *p;
 559
 560                 base = parent;
 561                 base_label = msg.parent_label;
 562                 next = commit;
 563                 next_label = msg.label;
 564
 565                 /*
 566                  * Append the commit log message to msgbuf; it starts
 567                  * after the tree, parent, author, committer
 568                  * information followed by "\n\n".
 569                  */
 570                 p = strstr(msg.message, "\n\n");
 571                 if (p) {
 572                         p += 2;
 573                         strbuf_addstr(&msgbuf, p);
 574                 }
 575
 576                 if (opts->record_origin) {
 577                         if (!has_conforming_footer(&msgbuf, NULL, 0))
 578                                 strbuf_addch(&msgbuf, '\n');
 579                         strbuf_addstr(&msgbuf, cherry_picked_prefix);
 580                         strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 581                         strbuf_addstr(&msgbuf, ")\n");
 582                 }
 583         }
 584
 585         if (!opts->strategy || !strcmp(opts->strategy, "recursive") || opts->action == REPLAY_REVERT) {
 586                 res = do_recursive_merge(base, next, base_label, next_label,
 587                                          head, &msgbuf, opts);
 588                 write_message(&msgbuf, defmsg);
 589         } else {
 590                 struct commit_list *common = NULL;
 591                 struct commit_list *remotes = NULL;
 592
 593                 write_message(&msgbuf, defmsg);
 594
 595                 commit_list_insert(base, &common);
 596                 commit_list_insert(next, &remotes);
 597                 res = try_merge_command(opts->strategy, opts->xopts_nr, opts->xopts,
 598                                         common, sha1_to_hex(head), remotes);
 599                 free_commit_list(common);
 600                 free_commit_list(remotes);
 601         }
 602
 603         /*
 604          * If the merge was clean or if it failed due to conflict, we write
 605          * CHERRY_PICK_HEAD for the subsequent invocation of commit to use.
 606          * However, if the merge did not even start, then we don't want to
 607          * write it at all.
 608          */
 609         if (opts->action == REPLAY_PICK && !opts->no_commit && (res == 0 || res == 1))
 610                 write_cherry_pick_head(commit, "CHERRY_PICK_HEAD");
 611         if (opts->action == REPLAY_REVERT && ((opts->no_commit && res == 0) || res == 1))
 612                 write_cherry_pick_head(commit, "REVERT_HEAD");
 613
 614         if (res) {
 615                 error(opts->action == REPLAY_REVERT
 616                       ? _("could not revert %s... %s")
 617                       : _("could not apply %s... %s"),
 618                       find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV),
 619                       msg.subject);
 620                 print_advice(res == 1, opts);
 621                 rerere(opts->allow_rerere_auto);
 622                 goto leave;
 623         }
 624
 625         allow = allow_empty(opts, commit);
 626         if (allow < 0) {
 627                 res = allow;
 628                 goto leave;
 629         }
 630         if (!opts->no_commit)
 631                 res = run_git_commit(defmsg, opts, allow);
 632
 633 leave:
 634         free_message(commit, &msg);
 635         free(defmsg);
 636
 637         return res;
 638 }
 639
 640 static void prepare_revs(struct replay_opts *opts)
 641 {
 642         /*
 643          * picking (but not reverting) ranges (but not individual revisions)
 644          * should be done in reverse
 645          */
 646         if (opts->action == REPLAY_PICK && !opts->revs->no_walk)
 647                 opts->revs->reverse ^= 1;
 648
 649         if (prepare_revision_walk(opts->revs))
 650                 die(_("revision walk setup failed"));
 651
 652         if (!opts->revs->commits)
 653                 die(_("empty commit set passed"));
 654 }
 655
 656 static void read_and_refresh_cache(struct replay_opts *opts)
 657 {
 658         static struct lock_file index_lock;
 659         int index_fd = hold_locked_index(&index_lock, 0);
 660         if (read_index_preload(&the_index, NULL) < 0)
 661                 die(_("git %s: failed to read the index"), action_name(opts));
 662         refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
 663         if (the_index.cache_changed && index_fd >= 0) {
 664                 if (write_locked_index(&the_index, &index_lock, COMMIT_LOCK))
 665                         die(_("git %s: failed to refresh the index"), action_name(opts));
 666         }
 667         rollback_lock_file(&index_lock);
 668 }
 669
 670 static int format_todo(struct strbuf *buf, struct commit_list *todo_list,
 671                 struct replay_opts *opts)
 672 {
 673         struct commit_list *cur = NULL;
 674         const char *sha1_abbrev = NULL;
 675         const char *action_str = opts->action == REPLAY_REVERT ? "revert" : "pick";
 676         const char *subject;
 677         int subject_len;
 678
 679         for (cur = todo_list; cur; cur = cur->next) {
 680                 const char *commit_buffer = get_commit_buffer(cur->item, NULL);
 681                 sha1_abbrev = find_unique_abbrev(cur->item->object.sha1, DEFAULT_ABBREV);
 682                 subject_len = find_commit_subject(commit_buffer, &subject);
 683                 strbuf_addf(buf, "%s %s %.*s\n", action_str, sha1_abbrev,
 684                         subject_len, subject);
 685                 unuse_commit_buffer(cur->item, commit_buffer);
 686         }
 687         return 0;
 688 }
 689
 690 static struct commit *parse_insn_line(char *bol, char *eol, struct replay_opts *opts)
 691 {
 692         unsigned char commit_sha1[20];
 693         enum replay_action action;
 694         char *end_of_object_name;
 695         int saved, status, padding;
 696
 697         if (starts_with(bol, "pick")) {
 698                 action = REPLAY_PICK;
 699                 bol += strlen("pick");
 700         } else if (starts_with(bol, "revert")) {
 701                 action = REPLAY_REVERT;
 702                 bol += strlen("revert");
 703         } else
 704                 return NULL;
 705
 706         /* Eat up extra spaces/ tabs before object name */
 707         padding = strspn(bol, " \t");
 708         if (!padding)
 709                 return NULL;
 710         bol += padding;
 711
 712         end_of_object_name = bol + strcspn(bol, " \t\n");
 713         saved = *end_of_object_name;
 714         *end_of_object_name = '\0';
 715         status = get_sha1(bol, commit_sha1);
 716         *end_of_object_name = saved;
 717
 718         /*
 719          * Verify that the action matches up with the one in
 720          * opts; we don't support arbitrary instructions
 721          */
 722         if (action != opts->action) {
 723                 const char *action_str;
 724                 action_str = action == REPLAY_REVERT ? "revert" : "cherry-pick";
 725                 error(_("Cannot %s during a %s"), action_str, action_name(opts));
 726                 return NULL;
 727         }
 728
 729         if (status < 0)
 730                 return NULL;
 731
 732         return lookup_commit_reference(commit_sha1);
 733 }
 734
 735 static int parse_insn_buffer(char *buf, struct commit_list **todo_list,
 736                         struct replay_opts *opts)
 737 {
 738         struct commit_list **next = todo_list;
 739         struct commit *commit;
 740         char *p = buf;
 741         int i;
 742
 743         for (i = 1; *p; i++) {
 744                 char *eol = strchrnul(p, '\n');
 745                 commit = parse_insn_line(p, eol, opts);
 746                 if (!commit)
 747                         return error(_("Could not parse line %d."), i);
 748                 next = commit_list_append(commit, next);
 749                 p = *eol ? eol + 1 : eol;
 750         }
 751         if (!*todo_list)
 752                 return error(_("No commits parsed."));
 753         return 0;
 754 }
 755
 756 static void read_populate_todo(struct commit_list **todo_list,
 757                         struct replay_opts *opts)
 758 {
 759         const char *todo_file = git_path(SEQ_TODO_FILE);
 760         struct strbuf buf = STRBUF_INIT;
 761         int fd, res;
 762
 763         fd = open(todo_file, O_RDONLY);
 764         if (fd < 0)
 765                 die_errno(_("Could not open %s"), todo_file);
 766         if (strbuf_read(&buf, fd, 0) < 0) {
 767                 close(fd);
 768                 strbuf_release(&buf);
 769                 die(_("Could not read %s."), todo_file);
 770         }
 771         close(fd);
 772
 773         res = parse_insn_buffer(buf.buf, todo_list, opts);
 774         strbuf_release(&buf);
 775         if (res)
 776                 die(_("Unusable instruction sheet: %s"), todo_file);
 777 }
 778
 779 static int populate_opts_cb(const char *key, const char *value, void *data)
 780 {
 781         struct replay_opts *opts = data;
 782         int error_flag = 1;
 783
 784         if (!value)
 785                 error_flag = 0;
 786         else if (!strcmp(key, "options.no-commit"))
 787                 opts->no_commit = git_config_bool_or_int(key, value, &error_flag);
 788         else if (!strcmp(key, "options.edit"))
 789                 opts->edit = git_config_bool_or_int(key, value, &error_flag);
 790         else if (!strcmp(key, "options.signoff"))
 791                 opts->signoff = git_config_bool_or_int(key, value, &error_flag);
 792         else if (!strcmp(key, "options.record-origin"))
 793                 opts->record_origin = git_config_bool_or_int(key, value, &error_flag);
 794         else if (!strcmp(key, "options.allow-ff"))
 795                 opts->allow_ff = git_config_bool_or_int(key, value, &error_flag);
 796         else if (!strcmp(key, "options.mainline"))
 797                 opts->mainline = git_config_int(key, value);
 798         else if (!strcmp(key, "options.strategy"))
 799                 git_config_string(&opts->strategy, key, value);
 800         else if (!strcmp(key, "options.gpg-sign"))
 801                 git_config_string(&opts->gpg_sign, key, value);
 802         else if (!strcmp(key, "options.strategy-option")) {
 803                 ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
 804                 opts->xopts[opts->xopts_nr++] = xstrdup(value);
 805         } else
 806                 return error(_("Invalid key: %s"), key);
 807
 808         if (!error_flag)
 809                 return error(_("Invalid value for %s: %s"), key, value);
 810
 811         return 0;
 812 }
 813
 814 static void read_populate_opts(struct replay_opts **opts_ptr)
 815 {
 816         const char *opts_file = git_path(SEQ_OPTS_FILE);
 817
 818         if (!file_exists(opts_file))
 819                 return;
 820         if (git_config_from_file(populate_opts_cb, opts_file, *opts_ptr) < 0)
 821                 die(_("Malformed options sheet: %s"), opts_file);
 822 }
 823
 824 static void walk_revs_populate_todo(struct commit_list **todo_list,
 825                                 struct replay_opts *opts)
 826 {
 827         struct commit *commit;
 828         struct commit_list **next;
 829
 830         prepare_revs(opts);
 831
 832         next = todo_list;
 833         while ((commit = get_revision(opts->revs)))
 834                 next = commit_list_append(commit, next);
 835 }
 836
 837 static int create_seq_dir(void)
 838 {
 839         const char *seq_dir = git_path(SEQ_DIR);
 840
 841         if (file_exists(seq_dir)) {
 842                 error(_("a cherry-pick or revert is already in progress"));
 843                 advise(_("try \"git cherry-pick (--continue | --quit | --abort)\""));
 844                 return -1;
 845         }
 846         else if (mkdir(seq_dir, 0777) < 0)
 847                 die_errno(_("Could not create sequencer directory %s"), seq_dir);
 848         return 0;
 849 }
 850
 851 static void save_head(const char *head)
 852 {
 853         const char *head_file = git_path(SEQ_HEAD_FILE);
 854         static struct lock_file head_lock;
 855         struct strbuf buf = STRBUF_INIT;
 856         int fd;
 857
 858         fd = hold_lock_file_for_update(&head_lock, head_file, LOCK_DIE_ON_ERROR);
 859         strbuf_addf(&buf, "%s\n", head);
 860         if (write_in_full(fd, buf.buf, buf.len) < 0)
 861                 die_errno(_("Could not write to %s"), head_file);
 862         if (commit_lock_file(&head_lock) < 0)
 863                 die(_("Error wrapping up %s."), head_file);
 864 }
 865
 866 static int reset_for_rollback(const unsigned char *sha1)
 867 {
 868         const char *argv[4];    /* reset --merge <arg> + NULL */
 869         argv[0] = "reset";
 870         argv[1] = "--merge";
 871         argv[2] = sha1_to_hex(sha1);
 872         argv[3] = NULL;
 873         return run_command_v_opt(argv, RUN_GIT_CMD);
 874 }
 875
 876 static int rollback_single_pick(void)
 877 {
 878         unsigned char head_sha1[20];
 879
 880         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
 881             !file_exists(git_path("REVERT_HEAD")))
 882                 return error(_("no cherry-pick or revert in progress"));
 883         if (read_ref_full("HEAD", 0, head_sha1, NULL))
 884                 return error(_("cannot resolve HEAD"));
 885         if (is_null_sha1(head_sha1))
 886                 return error(_("cannot abort from a branch yet to be born"));
 887         return reset_for_rollback(head_sha1);
 888 }
 889
 890 static int sequencer_rollback(struct replay_opts *opts)
 891 {
 892         const char *filename;
 893         FILE *f;
 894         unsigned char sha1[20];
 895         struct strbuf buf = STRBUF_INIT;
 896
 897         filename = git_path(SEQ_HEAD_FILE);
 898         f = fopen(filename, "r");
 899         if (!f && errno == ENOENT) {
 900                 /*
 901                  * There is no multiple-cherry-pick in progress.
 902                  * If CHERRY_PICK_HEAD or REVERT_HEAD indicates
 903                  * a single-cherry-pick in progress, abort that.
 904                  */
 905                 return rollback_single_pick();
 906         }
 907         if (!f)
 908                 return error(_("cannot open %s: %s"), filename,
 909                                                 strerror(errno));
 910         if (strbuf_getline(&buf, f, '\n')) {
 911                 error(_("cannot read %s: %s"), filename, ferror(f) ?
 912                         strerror(errno) : _("unexpected end of file"));
 913                 fclose(f);
 914                 goto fail;
 915         }
 916         fclose(f);
 917         if (get_sha1_hex(buf.buf, sha1) || buf.buf[40] != '\0') {
 918                 error(_("stored pre-cherry-pick HEAD file '%s' is corrupt"),
 919                         filename);
 920                 goto fail;
 921         }
 922         if (reset_for_rollback(sha1))
 923                 goto fail;
 924         remove_sequencer_state();
 925         strbuf_release(&buf);
 926         return 0;
 927 fail:
 928         strbuf_release(&buf);
 929         return -1;
 930 }
 931
 932 static void save_todo(struct commit_list *todo_list, struct replay_opts *opts)
 933 {
 934         const char *todo_file = git_path(SEQ_TODO_FILE);
 935         static struct lock_file todo_lock;
 936         struct strbuf buf = STRBUF_INIT;
 937         int fd;
 938
 939         fd = hold_lock_file_for_update(&todo_lock, todo_file, LOCK_DIE_ON_ERROR);
 940         if (format_todo(&buf, todo_list, opts) < 0)
 941                 die(_("Could not format %s."), todo_file);
 942         if (write_in_full(fd, buf.buf, buf.len) < 0) {
 943                 strbuf_release(&buf);
 944                 die_errno(_("Could not write to %s"), todo_file);
 945         }
 946         if (commit_lock_file(&todo_lock) < 0) {
 947                 strbuf_release(&buf);
 948                 die(_("Error wrapping up %s."), todo_file);
 949         }
 950         strbuf_release(&buf);
 951 }
 952
 953 static void save_opts(struct replay_opts *opts)
 954 {
 955         const char *opts_file = git_path(SEQ_OPTS_FILE);
 956
 957         if (opts->no_commit)
 958                 git_config_set_in_file(opts_file, "options.no-commit", "true");
 959         if (opts->edit)
 960                 git_config_set_in_file(opts_file, "options.edit", "true");
 961         if (opts->signoff)
 962                 git_config_set_in_file(opts_file, "options.signoff", "true");
 963         if (opts->record_origin)
 964                 git_config_set_in_file(opts_file, "options.record-origin", "true");
 965         if (opts->allow_ff)
 966                 git_config_set_in_file(opts_file, "options.allow-ff", "true");
 967         if (opts->mainline) {
 968                 struct strbuf buf = STRBUF_INIT;
 969                 strbuf_addf(&buf, "%d", opts->mainline);
 970                 git_config_set_in_file(opts_file, "options.mainline", buf.buf);
 971                 strbuf_release(&buf);
 972         }
 973         if (opts->strategy)
 974                 git_config_set_in_file(opts_file, "options.strategy", opts->strategy);
 975         if (opts->gpg_sign)
 976                 git_config_set_in_file(opts_file, "options.gpg-sign", opts->gpg_sign);
 977         if (opts->xopts) {
 978                 int i;
 979                 for (i = 0; i < opts->xopts_nr; i++)
 980                         git_config_set_multivar_in_file(opts_file,
 981                                                         "options.strategy-option",
 982                                                         opts->xopts[i], "^$", 0);
 983         }
 984 }
 985
 986 static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
 987 {
 988         struct commit_list *cur;
 989         int res;
 990
 991         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
 992         if (opts->allow_ff)
 993                 assert(!(opts->signoff || opts->no_commit ||
 994                                 opts->record_origin || opts->edit));
 995         read_and_refresh_cache(opts);
 996
 997         for (cur = todo_list; cur; cur = cur->next) {
 998                 save_todo(cur, opts);
 999                 res = do_pick_commit(cur->item, opts);
1000                 if (res)
1001                         return res;
1002         }
1003
1004         /*
1005          * Sequence of picks finished successfully; cleanup by
1006          * removing the .git/sequencer directory
1007          */
1008         remove_sequencer_state();
1009         return 0;
1010 }
1011
1012 static int continue_single_pick(void)
1013 {
1014         const char *argv[] = { "commit", NULL };
1015
1016         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
1017             !file_exists(git_path("REVERT_HEAD")))
1018                 return error(_("no cherry-pick or revert in progress"));
1019         return run_command_v_opt(argv, RUN_GIT_CMD);
1020 }
1021
1022 static int sequencer_continue(struct replay_opts *opts)
1023 {
1024         struct commit_list *todo_list = NULL;
1025
1026         if (!file_exists(git_path(SEQ_TODO_FILE)))
1027                 return continue_single_pick();
1028         read_populate_opts(&opts);
1029         read_populate_todo(&todo_list, opts);
1030
1031         /* Verify that the conflict has been resolved */
1032         if (file_exists(git_path("CHERRY_PICK_HEAD")) ||
1033             file_exists(git_path("REVERT_HEAD"))) {
1034                 int ret = continue_single_pick();
1035                 if (ret)
1036                         return ret;
1037         }
1038         if (index_differs_from("HEAD", 0))
1039                 return error_dirty_index(opts);
1040         todo_list = todo_list->next;
1041         return pick_commits(todo_list, opts);
1042 }
1043
1044 static int single_pick(struct commit *cmit, struct replay_opts *opts)
1045 {
1046         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
1047         return do_pick_commit(cmit, opts);
1048 }
1049
1050 int sequencer_pick_revisions(struct replay_opts *opts)
1051 {
1052         struct commit_list *todo_list = NULL;
1053         unsigned char sha1[20];
1054         int i;
1055
1056         if (opts->subcommand == REPLAY_NONE)
1057                 assert(opts->revs);
1058
1059         read_and_refresh_cache(opts);
1060
1061         /*
1062          * Decide what to do depending on the arguments; a fresh
1063          * cherry-pick should be handled differently from an existing
1064          * one that is being continued
1065          */
1066         if (opts->subcommand == REPLAY_REMOVE_STATE) {
1067                 remove_sequencer_state();
1068                 return 0;
1069         }
1070         if (opts->subcommand == REPLAY_ROLLBACK)
1071                 return sequencer_rollback(opts);
1072         if (opts->subcommand == REPLAY_CONTINUE)
1073                 return sequencer_continue(opts);
1074
1075         for (i = 0; i < opts->revs->pending.nr; i++) {
1076                 unsigned char sha1[20];
1077                 const char *name = opts->revs->pending.objects[i].name;
1078
1079                 /* This happens when using --stdin. */
1080                 if (!strlen(name))
1081                         continue;
1082
1083                 if (!get_sha1(name, sha1)) {
1084                         if (!lookup_commit_reference_gently(sha1, 1)) {
1085                                 enum object_type type = sha1_object_info(sha1, NULL);
1086                                 die(_("%s: can't cherry-pick a %s"), name, typename(type));
1087                         }
1088                 } else
1089                         die(_("%s: bad revision"), name);
1090         }
1091
1092         /*
1093          * If we were called as "git cherry-pick <commit>", just
1094          * cherry-pick/revert it, set CHERRY_PICK_HEAD /
1095          * REVERT_HEAD, and don't touch the sequencer state.
1096          * This means it is possible to cherry-pick in the middle
1097          * of a cherry-pick sequence.
1098          */
1099         if (opts->revs->cmdline.nr == 1 &&
1100             opts->revs->cmdline.rev->whence == REV_CMD_REV &&
1101             opts->revs->no_walk &&
1102             !opts->revs->cmdline.rev->flags) {
1103                 struct commit *cmit;
1104                 if (prepare_revision_walk(opts->revs))
1105                         die(_("revision walk setup failed"));
1106                 cmit = get_revision(opts->revs);
1107                 if (!cmit || get_revision(opts->revs))
1108                         die("BUG: expected exactly one commit from walk");
1109                 return single_pick(cmit, opts);
1110         }
1111
1112         /*
1113          * Start a new cherry-pick/ revert sequence; but
1114          * first, make sure that an existing one isn't in
1115          * progress
1116          */
1117
1118         walk_revs_populate_todo(&todo_list, opts);
1119         if (create_seq_dir() < 0)
1120                 return -1;
1121         if (get_sha1("HEAD", sha1)) {
1122                 if (opts->action == REPLAY_REVERT)
1123                         return error(_("Can't revert as initial commit"));
1124                 return error(_("Can't cherry-pick into empty head"));
1125         }
1126         save_head(sha1_to_hex(sha1));
1127         save_opts(opts);
1128         return pick_commits(todo_list, opts);
1129 }
1130
1131 void append_signoff(struct strbuf *msgbuf, int ignore_footer, unsigned flag)
1132 {
1133         unsigned no_dup_sob = flag & APPEND_SIGNOFF_DEDUP;
1134         struct strbuf sob = STRBUF_INIT;
1135         int has_footer;
1136
1137         strbuf_addstr(&sob, sign_off_header);
1138         strbuf_addstr(&sob, fmt_name(getenv("GIT_COMMITTER_NAME"),
1139                                 getenv("GIT_COMMITTER_EMAIL")));
1140         strbuf_addch(&sob, '\n');
1141
1142         /*
1143          * If the whole message buffer is equal to the sob, pretend that we
1144          * found a conforming footer with a matching sob
1145          */
1146         if (msgbuf->len - ignore_footer == sob.len &&
1147             !strncmp(msgbuf->buf, sob.buf, sob.len))
1148                 has_footer = 3;
1149         else
1150                 has_footer = has_conforming_footer(msgbuf, &sob, ignore_footer);
1151
1152         if (!has_footer) {
1153                 const char *append_newlines = NULL;
1154                 size_t len = msgbuf->len - ignore_footer;
1155
1156                 if (!len) {
1157                         /*
1158                          * The buffer is completely empty.  Leave foom for
1159                          * the title and body to be filled in by the user.
1160                          */
1161                         append_newlines = "\n\n";
1162                 } else if (msgbuf->buf[len - 1] != '\n') {
1163                         /*
1164                          * Incomplete line.  Complete the line and add a
1165                          * blank one so that there is an empty line between
1166                          * the message body and the sob.
1167                          */
1168                         append_newlines = "\n\n";
1169                 } else if (len == 1) {
1170                         /*
1171                          * Buffer contains a single newline.  Add another
1172                          * so that we leave room for the title and body.
1173                          */
1174                         append_newlines = "\n";
1175                 } else if (msgbuf->buf[len - 2] != '\n') {
1176                         /*
1177                          * Buffer ends with a single newline.  Add another
1178                          * so that there is an empty line between the message
1179                          * body and the sob.
1180                          */
1181                         append_newlines = "\n";
1182                 } /* else, the buffer already ends with two newlines. */
1183
1184                 if (append_newlines)
1185                         strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0,
1186                                 append_newlines, strlen(append_newlines));
1187         }
1188
1189         if (has_footer != 3 && (!no_dup_sob || has_footer != 2))
1190                 strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0,
1191                                 sob.buf, sob.len);
1192
1193         strbuf_release(&sob);
1194 }