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