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