sequencer.c

   1 #include "cache.h"
   2 #include "sequencer.h"
   3 #include "dir.h"
   4 #include "object.h"
   5 #include "commit.h"
   6 #include "tag.h"
   7 #include "run-command.h"
   8 #include "exec_cmd.h"
   9 #include "utf8.h"
  10 #include "cache-tree.h"
  11 #include "diff.h"
  12 #include "revision.h"
  13 #include "rerere.h"
  14 #include "merge-recursive.h"
  15 #include "refs.h"
  16 #include "argv-array.h"
  17
  18 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
  19
  20 const char sign_off_header[] = "Signed-off-by: ";
  21 static const char cherry_picked_prefix[] = "(cherry picked from commit ";
  22
  23 static int is_rfc2822_line(const char *buf, int len)
  24 {
  25         int i;
  26
  27         for (i = 0; i < len; i++) {
  28                 int ch = buf[i];
  29                 if (ch == ':')
  30                         return 1;
  31                 if (!isalnum(ch) && ch != '-')
  32                         break;
  33         }
  34
  35         return 0;
  36 }
  37
  38 static int is_cherry_picked_from_line(const char *buf, int len)
  39 {
  40         /*
  41          * We only care that it looks roughly like (cherry picked from ...)
  42          */
  43         return len > strlen(cherry_picked_prefix) + 1 &&
  44                 starts_with(buf, cherry_picked_prefix) && buf[len - 1] == ')';
  45 }
  46
  47 /*
  48  * Returns 0 for non-conforming footer
  49  * Returns 1 for conforming footer
  50  * Returns 2 when sob exists within conforming footer
  51  * Returns 3 when sob exists within conforming footer as last entry
  52  */
  53 static int has_conforming_footer(struct strbuf *sb, struct strbuf *sob,
  54         int ignore_footer)
  55 {
  56         char prev;
  57         int i, k;
  58         int len = sb->len - ignore_footer;
  59         const char *buf = sb->buf;
  60         int found_sob = 0;
  61
  62         /* footer must end with newline */
  63         if (!len || buf[len - 1] != '\n')
  64                 return 0;
  65
  66         prev = '\0';
  67         for (i = len - 1; i > 0; i--) {
  68                 char ch = buf[i];
  69                 if (prev == '\n' && ch == '\n') /* paragraph break */
  70                         break;
  71                 prev = ch;
  72         }
  73
  74         /* require at least one blank line */
  75         if (prev != '\n' || buf[i] != '\n')
  76                 return 0;
  77
  78         /* advance to start of last paragraph */
  79         while (i < len - 1 && buf[i] == '\n')
  80                 i++;
  81
  82         for (; i < len; i = k) {
  83                 int found_rfc2822;
  84
  85                 for (k = i; k < len && buf[k] != '\n'; k++)
  86                         ; /* do nothing */
  87                 k++;
  88
  89                 found_rfc2822 = is_rfc2822_line(buf + i, k - i - 1);
  90                 if (found_rfc2822 && sob &&
  91                     !strncmp(buf + i, sob->buf, sob->len))
  92                         found_sob = k;
  93
  94                 if (!(found_rfc2822 ||
  95                       is_cherry_picked_from_line(buf + i, k - i - 1)))
  96                         return 0;
  97         }
  98         if (found_sob == i)
  99                 return 3;
 100         if (found_sob)
 101                 return 2;
 102         return 1;
 103 }
 104
 105 static void remove_sequencer_state(void)
 106 {
 107         struct strbuf seq_dir = STRBUF_INIT;
 108
 109         strbuf_addf(&seq_dir, "%s", git_path(SEQ_DIR));
 110         remove_dir_recursively(&seq_dir, 0);
 111         strbuf_release(&seq_dir);
 112 }
 113
 114 static const char *action_name(const struct replay_opts *opts)
 115 {
 116         return opts->action == REPLAY_REVERT ? "revert" : "cherry-pick";
 117 }
 118
 119 struct commit_message {
 120         char *parent_label;
 121         const char *label;
 122         const char *subject;
 123         const char *message;
 124 };
 125
 126 static int get_message(struct commit *commit, struct commit_message *out)
 127 {
 128         const char *abbrev, *subject;
 129         int abbrev_len, subject_len;
 130         char *q;
 131
 132         if (!git_commit_encoding)
 133                 git_commit_encoding = "UTF-8";
 134
 135         out->message = logmsg_reencode(commit, NULL, git_commit_encoding);
 136         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
 137         abbrev_len = strlen(abbrev);
 138
 139         subject_len = find_commit_subject(out->message, &subject);
 140
 141         out->parent_label = xmalloc(strlen("parent of ") + abbrev_len +
 142                               strlen("... ") + subject_len + 1);
 143         q = out->parent_label;
 144         q = mempcpy(q, "parent of ", strlen("parent of "));
 145         out->label = q;
 146         q = mempcpy(q, abbrev, abbrev_len);
 147         q = mempcpy(q, "... ", strlen("... "));
 148         out->subject = q;
 149         q = mempcpy(q, subject, subject_len);
 150         *q = '\0';
 151         return 0;
 152 }
 153
 154 static void free_message(struct commit *commit, struct commit_message *msg)
 155 {
 156         free(msg->parent_label);
 157         unuse_commit_buffer(commit, msg->message);
 158 }
 159
 160 static void write_cherry_pick_head(struct commit *commit, const char *pseudoref)
 161 {
 162         const char *filename;
 163         int fd;
 164         struct strbuf buf = STRBUF_INIT;
 165
 166         strbuf_addf(&buf, "%s\n", sha1_to_hex(commit->object.sha1));
 167
 168         filename = git_path("%s", pseudoref);
 169         fd = open(filename, O_WRONLY | O_CREAT, 0666);
 170         if (fd < 0)
 171                 die_errno(_("Could not open '%s' for writing"), filename);
 172         if (write_in_full(fd, buf.buf, buf.len) != buf.len || close(fd))
 173                 die_errno(_("Could not write to '%s'"), filename);
 174         strbuf_release(&buf);
 175 }
 176
 177 static void print_advice(int show_hint, struct replay_opts *opts)
 178 {
 179         char *msg = getenv("GIT_CHERRY_PICK_HELP");
 180
 181         if (msg) {
 182                 fprintf(stderr, "%s\n", msg);
 183                 /*
 184                  * A conflict has occurred but the porcelain
 185                  * (typically rebase --interactive) wants to take care
 186                  * of the commit itself so remove CHERRY_PICK_HEAD
 187                  */
 188                 unlink(git_path("CHERRY_PICK_HEAD"));
 189                 return;
 190         }
 191
 192         if (show_hint) {
 193                 if (opts->no_commit)
 194                         advise(_("after resolving the conflicts, mark the corrected paths\n"
 195                                  "with 'git add <paths>' or 'git rm <paths>'"));
 196                 else
 197                         advise(_("after resolving the conflicts, mark the corrected paths\n"
 198                                  "with 'git add <paths>' or 'git rm <paths>'\n"
 199                                  "and commit the result with 'git commit'"));
 200         }
 201 }
 202
 203 static void write_message(struct strbuf *msgbuf, const char *filename)
 204 {
 205         static struct lock_file msg_file;
 206
 207         int msg_fd = hold_lock_file_for_update(&msg_file, filename,
 208                                                LOCK_DIE_ON_ERROR);
 209         if (write_in_full(msg_fd, msgbuf->buf, msgbuf->len) < 0)
 210                 die_errno(_("Could not write to %s"), filename);
 211         strbuf_release(msgbuf);
 212         if (commit_lock_file(&msg_file) < 0)
 213                 die(_("Error wrapping up %s"), filename);
 214 }
 215
 216 static struct tree *empty_tree(void)
 217 {
 218         return lookup_tree(EMPTY_TREE_SHA1_BIN);
 219 }
 220
 221 static int error_dirty_index(struct replay_opts *opts)
 222 {
 223         if (read_cache_unmerged())
 224                 return error_resolve_conflict(action_name(opts));
 225
 226         /* Different translation strings for cherry-pick and revert */
 227         if (opts->action == REPLAY_PICK)
 228                 error(_("Your local changes would be overwritten by cherry-pick."));
 229         else
 230                 error(_("Your local changes would be overwritten by revert."));
 231
 232         if (advice_commit_before_merge)
 233                 advise(_("Commit your changes or stash them to proceed."));
 234         return -1;
 235 }
 236
 237 static int fast_forward_to(const unsigned char *to, const unsigned char *from,
 238                         int unborn, struct replay_opts *opts)
 239 {
 240         struct ref_lock *ref_lock;
 241         struct strbuf sb = STRBUF_INIT;
 242         int ret;
 243
 244         read_cache();
 245         if (checkout_fast_forward(from, to, 1))
 246                 exit(1); /* the callee should have complained already */
 247         ref_lock = lock_any_ref_for_update("HEAD", unborn ? null_sha1 : from,
 248                                            0, NULL);
 249         strbuf_addf(&sb, "%s: fast-forward", action_name(opts));
 250         ret = write_ref_sha1(ref_lock, to, sb.buf);
 251         strbuf_release(&sb);
 252         return ret;
 253 }
 254
 255 static int do_recursive_merge(struct commit *base, struct commit *next,
 256                               const char *base_label, const char *next_label,
 257                               unsigned char *head, struct strbuf *msgbuf,
 258                               struct replay_opts *opts)
 259 {
 260         struct merge_options o;
 261         struct tree *result, *next_tree, *base_tree, *head_tree;
 262         int clean, index_fd;
 263         const char **xopt;
 264         static struct lock_file index_lock;
 265
 266         index_fd = hold_locked_index(&index_lock, 1);
 267
 268         read_cache();
 269
 270         init_merge_options(&o);
 271         o.ancestor = base ? base_label : "(empty tree)";
 272         o.branch1 = "HEAD";
 273         o.branch2 = next ? next_label : "(empty tree)";
 274
 275         head_tree = parse_tree_indirect(head);
 276         next_tree = next ? next->tree : empty_tree();
 277         base_tree = base ? base->tree : empty_tree();
 278
 279         for (xopt = opts->xopts; xopt != opts->xopts + opts->xopts_nr; xopt++)
 280                 parse_merge_opt(&o, *xopt);
 281
 282         clean = merge_trees(&o,
 283                             head_tree,
 284                             next_tree, base_tree, &result);
 285
 286         if (active_cache_changed &&
 287             (write_cache(index_fd, active_cache, active_nr) ||
 288              commit_locked_index(&index_lock)))
 289                 /* TRANSLATORS: %s will be "revert" or "cherry-pick" */
 290                 die(_("%s: Unable to write new index file"), action_name(opts));
 291         rollback_lock_file(&index_lock);
 292
 293         if (opts->signoff)
 294                 append_signoff(msgbuf, 0, 0);
 295
 296         if (!clean) {
 297                 int i;
 298                 strbuf_addstr(msgbuf, "\nConflicts:\n");
 299                 for (i = 0; i < active_nr;) {
 300                         const struct cache_entry *ce = active_cache[i++];
 301                         if (ce_stage(ce)) {
 302                                 strbuf_addch(msgbuf, '\t');
 303                                 strbuf_addstr(msgbuf, ce->name);
 304                                 strbuf_addch(msgbuf, '\n');
 305                                 while (i < active_nr && !strcmp(ce->name,
 306                                                 active_cache[i]->name))
 307                                         i++;
 308                         }
 309                 }
 310         }
 311
 312         return !clean;
 313 }
 314
 315 static int is_index_unchanged(void)
 316 {
 317         unsigned char head_sha1[20];
 318         struct commit *head_commit;
 319
 320         if (!resolve_ref_unsafe("HEAD", head_sha1, 1, NULL))
 321                 return error(_("Could not resolve HEAD commit\n"));
 322
 323         head_commit = lookup_commit(head_sha1);
 324
 325         /*
 326          * If head_commit is NULL, check_commit, called from
 327          * lookup_commit, would have indicated that head_commit is not
 328          * a commit object already.  parse_commit() will return failure
 329          * without further complaints in such a case.  Otherwise, if
 330          * the commit is invalid, parse_commit() will complain.  So
 331          * there is nothing for us to say here.  Just return failure.
 332          */
 333         if (parse_commit(head_commit))
 334                 return -1;
 335
 336         if (!active_cache_tree)
 337                 active_cache_tree = cache_tree();
 338
 339         if (!cache_tree_fully_valid(active_cache_tree))
 340                 if (cache_tree_update(active_cache_tree,
 341                                       (const struct cache_entry * const *)active_cache,
 342                                       active_nr, 0))
 343                         return error(_("Unable to update cache tree\n"));
 344
 345         return !hashcmp(active_cache_tree->sha1, head_commit->tree->object.sha1);
 346 }
 347
 348 /*
 349  * If we are cherry-pick, and if the merge did not result in
 350  * hand-editing, we will hit this commit and inherit the original
 351  * author date and name.
 352  * If we are revert, or if our cherry-pick results in a hand merge,
 353  * we had better say that the current user is responsible for that.
 354  */
 355 static int run_git_commit(const char *defmsg, struct replay_opts *opts,
 356                           int allow_empty)
 357 {
 358         struct argv_array array;
 359         int rc;
 360         char *gpg_sign;
 361
 362         argv_array_init(&array);
 363         argv_array_push(&array, "commit");
 364         argv_array_push(&array, "-n");
 365
 366         if (opts->gpg_sign) {
 367                 gpg_sign = xmalloc(3 + strlen(opts->gpg_sign));
 368                 sprintf(gpg_sign, "-S%s", opts->gpg_sign);
 369                 argv_array_push(&array, gpg_sign);
 370                 free(gpg_sign);
 371         }
 372         if (opts->signoff)
 373                 argv_array_push(&array, "-s");
 374         if (!opts->edit) {
 375                 argv_array_push(&array, "-F");
 376                 argv_array_push(&array, defmsg);
 377         }
 378
 379         if (allow_empty)
 380                 argv_array_push(&array, "--allow-empty");
 381
 382         if (opts->allow_empty_message)
 383                 argv_array_push(&array, "--allow-empty-message");
 384
 385         rc = run_command_v_opt(array.argv, RUN_GIT_CMD);
 386         argv_array_clear(&array);
 387         return rc;
 388 }
 389
 390 static int is_original_commit_empty(struct commit *commit)
 391 {
 392         const unsigned char *ptree_sha1;
 393
 394         if (parse_commit(commit))
 395                 return error(_("Could not parse commit %s\n"),
 396                              sha1_to_hex(commit->object.sha1));
 397         if (commit->parents) {
 398                 struct commit *parent = commit->parents->item;
 399                 if (parse_commit(parent))
 400                         return error(_("Could not parse parent commit %s\n"),
 401                                 sha1_to_hex(parent->object.sha1));
 402                 ptree_sha1 = parent->tree->object.sha1;
 403         } else {
 404                 ptree_sha1 = EMPTY_TREE_SHA1_BIN; /* commit is root */
 405         }
 406
 407         return !hashcmp(ptree_sha1, commit->tree->object.sha1);
 408 }
 409
 410 /*
 411  * Do we run "git commit" with "--allow-empty"?
 412  */
 413 static int allow_empty(struct replay_opts *opts, struct commit *commit)
 414 {
 415         int index_unchanged, empty_commit;
 416
 417         /*
 418          * Three cases:
 419          *
 420          * (1) we do not allow empty at all and error out.
 421          *
 422          * (2) we allow ones that were initially empty, but
 423          * forbid the ones that become empty;
 424          *
 425          * (3) we allow both.
 426          */
 427         if (!opts->allow_empty)
 428                 return 0; /* let "git commit" barf as necessary */
 429
 430         index_unchanged = is_index_unchanged();
 431         if (index_unchanged < 0)
 432                 return index_unchanged;
 433         if (!index_unchanged)
 434                 return 0; /* we do not have to say --allow-empty */
 435
 436         if (opts->keep_redundant_commits)
 437                 return 1;
 438
 439         empty_commit = is_original_commit_empty(commit);
 440         if (empty_commit < 0)
 441                 return empty_commit;
 442         if (!empty_commit)
 443                 return 0;
 444         else
 445                 return 1;
 446 }
 447
 448 static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
 449 {
 450         unsigned char head[20];
 451         struct commit *base, *next, *parent;
 452         const char *base_label, *next_label;
 453         struct commit_message msg = { NULL, NULL, NULL, NULL };
 454         char *defmsg = NULL;
 455         struct strbuf msgbuf = STRBUF_INIT;
 456         int res, unborn = 0, allow;
 457
 458         if (opts->no_commit) {
 459                 /*
 460                  * We do not intend to commit immediately.  We just want to
 461                  * merge the differences in, so let's compute the tree
 462                  * that represents the "current" state for merge-recursive
 463                  * to work on.
 464                  */
 465                 if (write_cache_as_tree(head, 0, NULL))
 466                         die (_("Your index file is unmerged."));
 467         } else {
 468                 unborn = get_sha1("HEAD", head);
 469                 if (unborn)
 470                         hashcpy(head, EMPTY_TREE_SHA1_BIN);
 471                 if (index_differs_from(unborn ? EMPTY_TREE_SHA1_HEX : "HEAD", 0))
 472                         return error_dirty_index(opts);
 473         }
 474         discard_cache();
 475
 476         if (!commit->parents) {
 477                 parent = NULL;
 478         }
 479         else if (commit->parents->next) {
 480                 /* Reverting or cherry-picking a merge commit */
 481                 int cnt;
 482                 struct commit_list *p;
 483
 484                 if (!opts->mainline)
 485                         return error(_("Commit %s is a merge but no -m option was given."),
 486                                 sha1_to_hex(commit->object.sha1));
 487
 488                 for (cnt = 1, p = commit->parents;
 489                      cnt != opts->mainline && p;
 490                      cnt++)
 491                         p = p->next;
 492                 if (cnt != opts->mainline || !p)
 493                         return error(_("Commit %s does not have parent %d"),
 494                                 sha1_to_hex(commit->object.sha1), opts->mainline);
 495                 parent = p->item;
 496         } else if (0 < opts->mainline)
 497                 return error(_("Mainline was specified but commit %s is not a merge."),
 498                         sha1_to_hex(commit->object.sha1));
 499         else
 500                 parent = commit->parents->item;
 501
 502         if (opts->allow_ff &&
 503             ((parent && !hashcmp(parent->object.sha1, head)) ||
 504              (!parent && unborn)))
 505                 return fast_forward_to(commit->object.sha1, head, unborn, opts);
 506
 507         if (parent && parse_commit(parent) < 0)
 508                 /* TRANSLATORS: The first %s will be "revert" or
 509                    "cherry-pick", the second %s a SHA1 */
 510                 return error(_("%s: cannot parse parent commit %s"),
 511                         action_name(opts), sha1_to_hex(parent->object.sha1));
 512
 513         if (get_message(commit, &msg) != 0)
 514                 return error(_("Cannot get commit message for %s"),
 515                         sha1_to_hex(commit->object.sha1));
 516
 517         /*
 518          * "commit" is an existing commit.  We would want to apply
 519          * the difference it introduces since its first parent "prev"
 520          * on top of the current HEAD if we are cherry-pick.  Or the
 521          * reverse of it if we are revert.
 522          */
 523
 524         defmsg = git_pathdup("MERGE_MSG");
 525
 526         if (opts->action == REPLAY_REVERT) {
 527                 base = commit;
 528                 base_label = msg.label;
 529                 next = parent;
 530                 next_label = msg.parent_label;
 531                 strbuf_addstr(&msgbuf, "Revert \"");
 532                 strbuf_addstr(&msgbuf, msg.subject);
 533                 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
 534                 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 535
 536                 if (commit->parents && commit->parents->next) {
 537                         strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
 538                         strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
 539                 }
 540                 strbuf_addstr(&msgbuf, ".\n");
 541         } else {
 542                 const char *p;
 543
 544                 base = parent;
 545                 base_label = msg.parent_label;
 546                 next = commit;
 547                 next_label = msg.label;
 548
 549                 /*
 550                  * Append the commit log message to msgbuf; it starts
 551                  * after the tree, parent, author, committer
 552                  * information followed by "\n\n".
 553                  */
 554                 p = strstr(msg.message, "\n\n");
 555                 if (p) {
 556                         p += 2;
 557                         strbuf_addstr(&msgbuf, p);
 558                 }
 559
 560                 if (opts->record_origin) {
 561                         if (!has_conforming_footer(&msgbuf, NULL, 0))
 562                                 strbuf_addch(&msgbuf, '\n');
 563                         strbuf_addstr(&msgbuf, cherry_picked_prefix);
 564                         strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 565                         strbuf_addstr(&msgbuf, ")\n");
 566                 }
 567         }
 568
 569         if (!opts->strategy || !strcmp(opts->strategy, "recursive") || opts->action == REPLAY_REVERT) {
 570                 res = do_recursive_merge(base, next, base_label, next_label,
 571                                          head, &msgbuf, opts);
 572                 write_message(&msgbuf, defmsg);
 573         } else {
 574                 struct commit_list *common = NULL;
 575                 struct commit_list *remotes = NULL;
 576
 577                 write_message(&msgbuf, defmsg);
 578
 579                 commit_list_insert(base, &common);
 580                 commit_list_insert(next, &remotes);
 581                 res = try_merge_command(opts->strategy, opts->xopts_nr, opts->xopts,
 582                                         common, sha1_to_hex(head), remotes);
 583                 free_commit_list(common);
 584                 free_commit_list(remotes);
 585         }
 586
 587         /*
 588          * If the merge was clean or if it failed due to conflict, we write
 589          * CHERRY_PICK_HEAD for the subsequent invocation of commit to use.
 590          * However, if the merge did not even start, then we don't want to
 591          * write it at all.
 592          */
 593         if (opts->action == REPLAY_PICK && !opts->no_commit && (res == 0 || res == 1))
 594                 write_cherry_pick_head(commit, "CHERRY_PICK_HEAD");
 595         if (opts->action == REPLAY_REVERT && ((opts->no_commit && res == 0) || res == 1))
 596                 write_cherry_pick_head(commit, "REVERT_HEAD");
 597
 598         if (res) {
 599                 error(opts->action == REPLAY_REVERT
 600                       ? _("could not revert %s... %s")
 601                       : _("could not apply %s... %s"),
 602                       find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV),
 603                       msg.subject);
 604                 print_advice(res == 1, opts);
 605                 rerere(opts->allow_rerere_auto);
 606                 goto leave;
 607         }
 608
 609         allow = allow_empty(opts, commit);
 610         if (allow < 0) {
 611                 res = allow;
 612                 goto leave;
 613         }
 614         if (!opts->no_commit)
 615                 res = run_git_commit(defmsg, opts, allow);
 616
 617 leave:
 618         free_message(commit, &msg);
 619         free(defmsg);
 620
 621         return res;
 622 }
 623
 624 static void prepare_revs(struct replay_opts *opts)
 625 {
 626         /*
 627          * picking (but not reverting) ranges (but not individual revisions)
 628          * should be done in reverse
 629          */
 630         if (opts->action == REPLAY_PICK && !opts->revs->no_walk)
 631                 opts->revs->reverse ^= 1;
 632
 633         if (prepare_revision_walk(opts->revs))
 634                 die(_("revision walk setup failed"));
 635
 636         if (!opts->revs->commits)
 637                 die(_("empty commit set passed"));
 638 }
 639
 640 static void read_and_refresh_cache(struct replay_opts *opts)
 641 {
 642         static struct lock_file index_lock;
 643         int index_fd = hold_locked_index(&index_lock, 0);
 644         if (read_index_preload(&the_index, NULL) < 0)
 645                 die(_("git %s: failed to read the index"), action_name(opts));
 646         refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
 647         if (the_index.cache_changed) {
 648                 if (write_index(&the_index, index_fd) ||
 649                     commit_locked_index(&index_lock))
 650                         die(_("git %s: failed to refresh the index"), action_name(opts));
 651         }
 652         rollback_lock_file(&index_lock);
 653 }
 654
 655 static int format_todo(struct strbuf *buf, struct commit_list *todo_list,
 656                 struct replay_opts *opts)
 657 {
 658         struct commit_list *cur = NULL;
 659         const char *sha1_abbrev = NULL;
 660         const char *action_str = opts->action == REPLAY_REVERT ? "revert" : "pick";
 661         const char *subject;
 662         int subject_len;
 663
 664         for (cur = todo_list; cur; cur = cur->next) {
 665                 const char *commit_buffer = get_commit_buffer(cur->item, NULL);
 666                 sha1_abbrev = find_unique_abbrev(cur->item->object.sha1, DEFAULT_ABBREV);
 667                 subject_len = find_commit_subject(commit_buffer, &subject);
 668                 strbuf_addf(buf, "%s %s %.*s\n", action_str, sha1_abbrev,
 669                         subject_len, subject);
 670                 unuse_commit_buffer(cur->item, commit_buffer);
 671         }
 672         return 0;
 673 }
 674
 675 static struct commit *parse_insn_line(char *bol, char *eol, struct replay_opts *opts)
 676 {
 677         unsigned char commit_sha1[20];
 678         enum replay_action action;
 679         char *end_of_object_name;
 680         int saved, status, padding;
 681
 682         if (starts_with(bol, "pick")) {
 683                 action = REPLAY_PICK;
 684                 bol += strlen("pick");
 685         } else if (starts_with(bol, "revert")) {
 686                 action = REPLAY_REVERT;
 687                 bol += strlen("revert");
 688         } else
 689                 return NULL;
 690
 691         /* Eat up extra spaces/ tabs before object name */
 692         padding = strspn(bol, " \t");
 693         if (!padding)
 694                 return NULL;
 695         bol += padding;
 696
 697         end_of_object_name = bol + strcspn(bol, " \t\n");
 698         saved = *end_of_object_name;
 699         *end_of_object_name = '\0';
 700         status = get_sha1(bol, commit_sha1);
 701         *end_of_object_name = saved;
 702
 703         /*
 704          * Verify that the action matches up with the one in
 705          * opts; we don't support arbitrary instructions
 706          */
 707         if (action != opts->action) {
 708                 const char *action_str;
 709                 action_str = action == REPLAY_REVERT ? "revert" : "cherry-pick";
 710                 error(_("Cannot %s during a %s"), action_str, action_name(opts));
 711                 return NULL;
 712         }
 713
 714         if (status < 0)
 715                 return NULL;
 716
 717         return lookup_commit_reference(commit_sha1);
 718 }
 719
 720 static int parse_insn_buffer(char *buf, struct commit_list **todo_list,
 721                         struct replay_opts *opts)
 722 {
 723         struct commit_list **next = todo_list;
 724         struct commit *commit;
 725         char *p = buf;
 726         int i;
 727
 728         for (i = 1; *p; i++) {
 729                 char *eol = strchrnul(p, '\n');
 730                 commit = parse_insn_line(p, eol, opts);
 731                 if (!commit)
 732                         return error(_("Could not parse line %d."), i);
 733                 next = commit_list_append(commit, next);
 734                 p = *eol ? eol + 1 : eol;
 735         }
 736         if (!*todo_list)
 737                 return error(_("No commits parsed."));
 738         return 0;
 739 }
 740
 741 static void read_populate_todo(struct commit_list **todo_list,
 742                         struct replay_opts *opts)
 743 {
 744         const char *todo_file = git_path(SEQ_TODO_FILE);
 745         struct strbuf buf = STRBUF_INIT;
 746         int fd, res;
 747
 748         fd = open(todo_file, O_RDONLY);
 749         if (fd < 0)
 750                 die_errno(_("Could not open %s"), todo_file);
 751         if (strbuf_read(&buf, fd, 0) < 0) {
 752                 close(fd);
 753                 strbuf_release(&buf);
 754                 die(_("Could not read %s."), todo_file);
 755         }
 756         close(fd);
 757
 758         res = parse_insn_buffer(buf.buf, todo_list, opts);
 759         strbuf_release(&buf);
 760         if (res)
 761                 die(_("Unusable instruction sheet: %s"), todo_file);
 762 }
 763
 764 static int populate_opts_cb(const char *key, const char *value, void *data)
 765 {
 766         struct replay_opts *opts = data;
 767         int error_flag = 1;
 768
 769         if (!value)
 770                 error_flag = 0;
 771         else if (!strcmp(key, "options.no-commit"))
 772                 opts->no_commit = git_config_bool_or_int(key, value, &error_flag);
 773         else if (!strcmp(key, "options.edit"))
 774                 opts->edit = git_config_bool_or_int(key, value, &error_flag);
 775         else if (!strcmp(key, "options.signoff"))
 776                 opts->signoff = git_config_bool_or_int(key, value, &error_flag);
 777         else if (!strcmp(key, "options.record-origin"))
 778                 opts->record_origin = git_config_bool_or_int(key, value, &error_flag);
 779         else if (!strcmp(key, "options.allow-ff"))
 780                 opts->allow_ff = git_config_bool_or_int(key, value, &error_flag);
 781         else if (!strcmp(key, "options.mainline"))
 782                 opts->mainline = git_config_int(key, value);
 783         else if (!strcmp(key, "options.strategy"))
 784                 git_config_string(&opts->strategy, key, value);
 785         else if (!strcmp(key, "options.gpg-sign"))
 786                 git_config_string(&opts->gpg_sign, key, value);
 787         else if (!strcmp(key, "options.strategy-option")) {
 788                 ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
 789                 opts->xopts[opts->xopts_nr++] = xstrdup(value);
 790         } else
 791                 return error(_("Invalid key: %s"), key);
 792
 793         if (!error_flag)
 794                 return error(_("Invalid value for %s: %s"), key, value);
 795
 796         return 0;
 797 }
 798
 799 static void read_populate_opts(struct replay_opts **opts_ptr)
 800 {
 801         const char *opts_file = git_path(SEQ_OPTS_FILE);
 802
 803         if (!file_exists(opts_file))
 804                 return;
 805         if (git_config_from_file(populate_opts_cb, opts_file, *opts_ptr) < 0)
 806                 die(_("Malformed options sheet: %s"), opts_file);
 807 }
 808
 809 static void walk_revs_populate_todo(struct commit_list **todo_list,
 810                                 struct replay_opts *opts)
 811 {
 812         struct commit *commit;
 813         struct commit_list **next;
 814
 815         prepare_revs(opts);
 816
 817         next = todo_list;
 818         while ((commit = get_revision(opts->revs)))
 819                 next = commit_list_append(commit, next);
 820 }
 821
 822 static int create_seq_dir(void)
 823 {
 824         const char *seq_dir = git_path(SEQ_DIR);
 825
 826         if (file_exists(seq_dir)) {
 827                 error(_("a cherry-pick or revert is already in progress"));
 828                 advise(_("try \"git cherry-pick (--continue | --quit | --abort)\""));
 829                 return -1;
 830         }
 831         else if (mkdir(seq_dir, 0777) < 0)
 832                 die_errno(_("Could not create sequencer directory %s"), seq_dir);
 833         return 0;
 834 }
 835
 836 static void save_head(const char *head)
 837 {
 838         const char *head_file = git_path(SEQ_HEAD_FILE);
 839         static struct lock_file head_lock;
 840         struct strbuf buf = STRBUF_INIT;
 841         int fd;
 842
 843         fd = hold_lock_file_for_update(&head_lock, head_file, LOCK_DIE_ON_ERROR);
 844         strbuf_addf(&buf, "%s\n", head);
 845         if (write_in_full(fd, buf.buf, buf.len) < 0)
 846                 die_errno(_("Could not write to %s"), head_file);
 847         if (commit_lock_file(&head_lock) < 0)
 848                 die(_("Error wrapping up %s."), head_file);
 849 }
 850
 851 static int reset_for_rollback(const unsigned char *sha1)
 852 {
 853         const char *argv[4];    /* reset --merge <arg> + NULL */
 854         argv[0] = "reset";
 855         argv[1] = "--merge";
 856         argv[2] = sha1_to_hex(sha1);
 857         argv[3] = NULL;
 858         return run_command_v_opt(argv, RUN_GIT_CMD);
 859 }
 860
 861 static int rollback_single_pick(void)
 862 {
 863         unsigned char head_sha1[20];
 864
 865         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
 866             !file_exists(git_path("REVERT_HEAD")))
 867                 return error(_("no cherry-pick or revert in progress"));
 868         if (read_ref_full("HEAD", head_sha1, 0, NULL))
 869                 return error(_("cannot resolve HEAD"));
 870         if (is_null_sha1(head_sha1))
 871                 return error(_("cannot abort from a branch yet to be born"));
 872         return reset_for_rollback(head_sha1);
 873 }
 874
 875 static int sequencer_rollback(struct replay_opts *opts)
 876 {
 877         const char *filename;
 878         FILE *f;
 879         unsigned char sha1[20];
 880         struct strbuf buf = STRBUF_INIT;
 881
 882         filename = git_path(SEQ_HEAD_FILE);
 883         f = fopen(filename, "r");
 884         if (!f && errno == ENOENT) {
 885                 /*
 886                  * There is no multiple-cherry-pick in progress.
 887                  * If CHERRY_PICK_HEAD or REVERT_HEAD indicates
 888                  * a single-cherry-pick in progress, abort that.
 889                  */
 890                 return rollback_single_pick();
 891         }
 892         if (!f)
 893                 return error(_("cannot open %s: %s"), filename,
 894                                                 strerror(errno));
 895         if (strbuf_getline(&buf, f, '\n')) {
 896                 error(_("cannot read %s: %s"), filename, ferror(f) ?
 897                         strerror(errno) : _("unexpected end of file"));
 898                 fclose(f);
 899                 goto fail;
 900         }
 901         fclose(f);
 902         if (get_sha1_hex(buf.buf, sha1) || buf.buf[40] != '\0') {
 903                 error(_("stored pre-cherry-pick HEAD file '%s' is corrupt"),
 904                         filename);
 905                 goto fail;
 906         }
 907         if (reset_for_rollback(sha1))
 908                 goto fail;
 909         remove_sequencer_state();
 910         strbuf_release(&buf);
 911         return 0;
 912 fail:
 913         strbuf_release(&buf);
 914         return -1;
 915 }
 916
 917 static void save_todo(struct commit_list *todo_list, struct replay_opts *opts)
 918 {
 919         const char *todo_file = git_path(SEQ_TODO_FILE);
 920         static struct lock_file todo_lock;
 921         struct strbuf buf = STRBUF_INIT;
 922         int fd;
 923
 924         fd = hold_lock_file_for_update(&todo_lock, todo_file, LOCK_DIE_ON_ERROR);
 925         if (format_todo(&buf, todo_list, opts) < 0)
 926                 die(_("Could not format %s."), todo_file);
 927         if (write_in_full(fd, buf.buf, buf.len) < 0) {
 928                 strbuf_release(&buf);
 929                 die_errno(_("Could not write to %s"), todo_file);
 930         }
 931         if (commit_lock_file(&todo_lock) < 0) {
 932                 strbuf_release(&buf);
 933                 die(_("Error wrapping up %s."), todo_file);
 934         }
 935         strbuf_release(&buf);
 936 }
 937
 938 static void save_opts(struct replay_opts *opts)
 939 {
 940         const char *opts_file = git_path(SEQ_OPTS_FILE);
 941
 942         if (opts->no_commit)
 943                 git_config_set_in_file(opts_file, "options.no-commit", "true");
 944         if (opts->edit)
 945                 git_config_set_in_file(opts_file, "options.edit", "true");
 946         if (opts->signoff)
 947                 git_config_set_in_file(opts_file, "options.signoff", "true");
 948         if (opts->record_origin)
 949                 git_config_set_in_file(opts_file, "options.record-origin", "true");
 950         if (opts->allow_ff)
 951                 git_config_set_in_file(opts_file, "options.allow-ff", "true");
 952         if (opts->mainline) {
 953                 struct strbuf buf = STRBUF_INIT;
 954                 strbuf_addf(&buf, "%d", opts->mainline);
 955                 git_config_set_in_file(opts_file, "options.mainline", buf.buf);
 956                 strbuf_release(&buf);
 957         }
 958         if (opts->strategy)
 959                 git_config_set_in_file(opts_file, "options.strategy", opts->strategy);
 960         if (opts->gpg_sign)
 961                 git_config_set_in_file(opts_file, "options.gpg-sign", opts->gpg_sign);
 962         if (opts->xopts) {
 963                 int i;
 964                 for (i = 0; i < opts->xopts_nr; i++)
 965                         git_config_set_multivar_in_file(opts_file,
 966                                                         "options.strategy-option",
 967                                                         opts->xopts[i], "^$", 0);
 968         }
 969 }
 970
 971 static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
 972 {
 973         struct commit_list *cur;
 974         int res;
 975
 976         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
 977         if (opts->allow_ff)
 978                 assert(!(opts->signoff || opts->no_commit ||
 979                                 opts->record_origin || opts->edit));
 980         read_and_refresh_cache(opts);
 981
 982         for (cur = todo_list; cur; cur = cur->next) {
 983                 save_todo(cur, opts);
 984                 res = do_pick_commit(cur->item, opts);
 985                 if (res)
 986                         return res;
 987         }
 988
 989         /*
 990          * Sequence of picks finished successfully; cleanup by
 991          * removing the .git/sequencer directory
 992          */
 993         remove_sequencer_state();
 994         return 0;
 995 }
 996
 997 static int continue_single_pick(void)
 998 {
 999         const char *argv[] = { "commit", NULL };
1000
1001         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
1002             !file_exists(git_path("REVERT_HEAD")))
1003                 return error(_("no cherry-pick or revert in progress"));
1004         return run_command_v_opt(argv, RUN_GIT_CMD);
1005 }
1006
1007 static int sequencer_continue(struct replay_opts *opts)
1008 {
1009         struct commit_list *todo_list = NULL;
1010
1011         if (!file_exists(git_path(SEQ_TODO_FILE)))
1012                 return continue_single_pick();
1013         read_populate_opts(&opts);
1014         read_populate_todo(&todo_list, opts);
1015
1016         /* Verify that the conflict has been resolved */
1017         if (file_exists(git_path("CHERRY_PICK_HEAD")) ||
1018             file_exists(git_path("REVERT_HEAD"))) {
1019                 int ret = continue_single_pick();
1020                 if (ret)
1021                         return ret;
1022         }
1023         if (index_differs_from("HEAD", 0))
1024                 return error_dirty_index(opts);
1025         todo_list = todo_list->next;
1026         return pick_commits(todo_list, opts);
1027 }
1028
1029 static int single_pick(struct commit *cmit, struct replay_opts *opts)
1030 {
1031         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
1032         return do_pick_commit(cmit, opts);
1033 }
1034
1035 int sequencer_pick_revisions(struct replay_opts *opts)
1036 {
1037         struct commit_list *todo_list = NULL;
1038         unsigned char sha1[20];
1039         int i;
1040
1041         if (opts->subcommand == REPLAY_NONE)
1042                 assert(opts->revs);
1043
1044         read_and_refresh_cache(opts);
1045
1046         /*
1047          * Decide what to do depending on the arguments; a fresh
1048          * cherry-pick should be handled differently from an existing
1049          * one that is being continued
1050          */
1051         if (opts->subcommand == REPLAY_REMOVE_STATE) {
1052                 remove_sequencer_state();
1053                 return 0;
1054         }
1055         if (opts->subcommand == REPLAY_ROLLBACK)
1056                 return sequencer_rollback(opts);
1057         if (opts->subcommand == REPLAY_CONTINUE)
1058                 return sequencer_continue(opts);
1059
1060         for (i = 0; i < opts->revs->pending.nr; i++) {
1061                 unsigned char sha1[20];
1062                 const char *name = opts->revs->pending.objects[i].name;
1063
1064                 /* This happens when using --stdin. */
1065                 if (!strlen(name))
1066                         continue;
1067
1068                 if (!get_sha1(name, sha1)) {
1069                         if (!lookup_commit_reference_gently(sha1, 1)) {
1070                                 enum object_type type = sha1_object_info(sha1, NULL);
1071                                 die(_("%s: can't cherry-pick a %s"), name, typename(type));
1072                         }
1073                 } else
1074                         die(_("%s: bad revision"), name);
1075         }
1076
1077         /*
1078          * If we were called as "git cherry-pick <commit>", just
1079          * cherry-pick/revert it, set CHERRY_PICK_HEAD /
1080          * REVERT_HEAD, and don't touch the sequencer state.
1081          * This means it is possible to cherry-pick in the middle
1082          * of a cherry-pick sequence.
1083          */
1084         if (opts->revs->cmdline.nr == 1 &&
1085             opts->revs->cmdline.rev->whence == REV_CMD_REV &&
1086             opts->revs->no_walk &&
1087             !opts->revs->cmdline.rev->flags) {
1088                 struct commit *cmit;
1089                 if (prepare_revision_walk(opts->revs))
1090                         die(_("revision walk setup failed"));
1091                 cmit = get_revision(opts->revs);
1092                 if (!cmit || get_revision(opts->revs))
1093                         die("BUG: expected exactly one commit from walk");
1094                 return single_pick(cmit, opts);
1095         }
1096
1097         /*
1098          * Start a new cherry-pick/ revert sequence; but
1099          * first, make sure that an existing one isn't in
1100          * progress
1101          */
1102
1103         walk_revs_populate_todo(&todo_list, opts);
1104         if (create_seq_dir() < 0)
1105                 return -1;
1106         if (get_sha1("HEAD", sha1)) {
1107                 if (opts->action == REPLAY_REVERT)
1108                         return error(_("Can't revert as initial commit"));
1109                 return error(_("Can't cherry-pick into empty head"));
1110         }
1111         save_head(sha1_to_hex(sha1));
1112         save_opts(opts);
1113         return pick_commits(todo_list, opts);
1114 }
1115
1116 void append_signoff(struct strbuf *msgbuf, int ignore_footer, unsigned flag)
1117 {
1118         unsigned no_dup_sob = flag & APPEND_SIGNOFF_DEDUP;
1119         struct strbuf sob = STRBUF_INIT;
1120         int has_footer;
1121
1122         strbuf_addstr(&sob, sign_off_header);
1123         strbuf_addstr(&sob, fmt_name(getenv("GIT_COMMITTER_NAME"),
1124                                 getenv("GIT_COMMITTER_EMAIL")));
1125         strbuf_addch(&sob, '\n');
1126
1127         /*
1128          * If the whole message buffer is equal to the sob, pretend that we
1129          * found a conforming footer with a matching sob
1130          */
1131         if (msgbuf->len - ignore_footer == sob.len &&
1132             !strncmp(msgbuf->buf, sob.buf, sob.len))
1133                 has_footer = 3;
1134         else
1135                 has_footer = has_conforming_footer(msgbuf, &sob, ignore_footer);
1136
1137         if (!has_footer) {
1138                 const char *append_newlines = NULL;
1139                 size_t len = msgbuf->len - ignore_footer;
1140
1141                 if (!len) {
1142                         /*
1143                          * The buffer is completely empty.  Leave foom for
1144                          * the title and body to be filled in by the user.
1145                          */
1146                         append_newlines = "\n\n";
1147                 } else if (msgbuf->buf[len - 1] != '\n') {
1148                         /*
1149                          * Incomplete line.  Complete the line and add a
1150                          * blank one so that there is an empty line between
1151                          * the message body and the sob.
1152                          */
1153                         append_newlines = "\n\n";
1154                 } else if (len == 1) {
1155                         /*
1156                          * Buffer contains a single newline.  Add another
1157                          * so that we leave room for the title and body.
1158                          */
1159                         append_newlines = "\n";
1160                 } else if (msgbuf->buf[len - 2] != '\n') {
1161                         /*
1162                          * Buffer ends with a single newline.  Add another
1163                          * so that there is an empty line between the message
1164                          * body and the sob.
1165                          */
1166                         append_newlines = "\n";
1167                 } /* else, the buffer already ends with two newlines. */
1168
1169                 if (append_newlines)
1170                         strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0,
1171                                 append_newlines, strlen(append_newlines));
1172         }
1173
1174         if (has_footer != 3 && (!no_dup_sob || has_footer != 2))
1175                 strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0,
1176                                 sob.buf, sob.len);
1177
1178         strbuf_release(&sob);
1179 }