git.oblomov.eu Git - git/blob - sequencer.c

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