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

   1 #include "cache.h"
   2 #include "lockfile.h"
   3 #include "sequencer.h"
   4 #include "dir.h"
   5 #include "object.h"
   6 #include "commit.h"
   7 #include "tag.h"
   8 #include "run-command.h"
   9 #include "exec_cmd.h"
  10 #include "utf8.h"
  11 #include "cache-tree.h"
  12 #include "diff.h"
  13 #include "revision.h"
  14 #include "rerere.h"
  15 #include "merge-recursive.h"
  16 #include "refs.h"
  17 #include "argv-array.h"
  18
  19 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
  20
  21 const char sign_off_header[] = "Signed-off-by: ";
  22 static const char cherry_picked_prefix[] = "(cherry picked from commit ";
  23
  24 static int is_rfc2822_line(const char *buf, int len)
  25 {
  26         int i;
  27
  28         for (i = 0; i < len; i++) {
  29                 int ch = buf[i];
  30                 if (ch == ':')
  31                         return 1;
  32                 if (!isalnum(ch) && ch != '-')
  33                         break;
  34         }
  35
  36         return 0;
  37 }
  38
  39 static int is_cherry_picked_from_line(const char *buf, int len)
  40 {
  41         /*
  42          * We only care that it looks roughly like (cherry picked from ...)
  43          */
  44         return len > strlen(cherry_picked_prefix) + 1 &&
  45                 starts_with(buf, cherry_picked_prefix) && buf[len - 1] == ')';
  46 }
  47
  48 /*
  49  * Returns 0 for non-conforming footer
  50  * Returns 1 for conforming footer
  51  * Returns 2 when sob exists within conforming footer
  52  * Returns 3 when sob exists within conforming footer as last entry
  53  */
  54 static int has_conforming_footer(struct strbuf *sb, struct strbuf *sob,
  55         int ignore_footer)
  56 {
  57         char prev;
  58         int i, k;
  59         int len = sb->len - ignore_footer;
  60         const char *buf = sb->buf;
  61         int found_sob = 0;
  62
  63         /* footer must end with newline */
  64         if (!len || buf[len - 1] != '\n')
  65                 return 0;
  66
  67         prev = '\0';
  68         for (i = len - 1; i > 0; i--) {
  69                 char ch = buf[i];
  70                 if (prev == '\n' && ch == '\n') /* paragraph break */
  71                         break;
  72                 prev = ch;
  73         }
  74
  75         /* require at least one blank line */
  76         if (prev != '\n' || buf[i] != '\n')
  77                 return 0;
  78
  79         /* advance to start of last paragraph */
  80         while (i < len - 1 && buf[i] == '\n')
  81                 i++;
  82
  83         for (; i < len; i = k) {
  84                 int found_rfc2822;
  85
  86                 for (k = i; k < len && buf[k] != '\n'; k++)
  87                         ; /* do nothing */
  88                 k++;
  89
  90                 found_rfc2822 = is_rfc2822_line(buf + i, k - i - 1);
  91                 if (found_rfc2822 && sob &&
  92                     !strncmp(buf + i, sob->buf, sob->len))
  93                         found_sob = k;
  94
  95                 if (!(found_rfc2822 ||
  96                       is_cherry_picked_from_line(buf + i, k - i - 1)))
  97                         return 0;
  98         }
  99         if (found_sob == i)
 100                 return 3;
 101         if (found_sob)
 102                 return 2;
 103         return 1;
 104 }
 105
 106 static void remove_sequencer_state(void)
 107 {
 108         struct strbuf seq_dir = STRBUF_INIT;
 109
 110         strbuf_addf(&seq_dir, "%s", git_path(SEQ_DIR));
 111         remove_dir_recursively(&seq_dir, 0);
 112         strbuf_release(&seq_dir);
 113 }
 114
 115 static const char *action_name(const struct replay_opts *opts)
 116 {
 117         return opts->action == REPLAY_REVERT ? "revert" : "cherry-pick";
 118 }
 119
 120 struct commit_message {
 121         char *parent_label;
 122         const char *label;
 123         const char *subject;
 124         const char *message;
 125 };
 126
 127 static int get_message(struct commit *commit, struct commit_message *out)
 128 {
 129         const char *abbrev, *subject;
 130         int abbrev_len, subject_len;
 131         char *q;
 132
 133         if (!git_commit_encoding)
 134                 git_commit_encoding = "UTF-8";
 135
 136         out->message = logmsg_reencode(commit, NULL, git_commit_encoding);
 137         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
 138         abbrev_len = strlen(abbrev);
 139
 140         subject_len = find_commit_subject(out->message, &subject);
 141
 142         out->parent_label = xmalloc(strlen("parent of ") + abbrev_len +
 143                               strlen("... ") + subject_len + 1);
 144         q = out->parent_label;
 145         q = mempcpy(q, "parent of ", strlen("parent of "));
 146         out->label = q;
 147         q = mempcpy(q, abbrev, abbrev_len);
 148         q = mempcpy(q, "... ", strlen("... "));
 149         out->subject = q;
 150         q = mempcpy(q, subject, subject_len);
 151         *q = '\0';
 152         return 0;
 153 }
 154
 155 static void free_message(struct commit *commit, struct commit_message *msg)
 156 {
 157         free(msg->parent_label);
 158         unuse_commit_buffer(commit, msg->message);
 159 }
 160
 161 static void write_cherry_pick_head(struct commit *commit, const char *pseudoref)
 162 {
 163         const char *filename;
 164         int fd;
 165         struct strbuf buf = STRBUF_INIT;
 166
 167         strbuf_addf(&buf, "%s\n", sha1_to_hex(commit->object.sha1));
 168
 169         filename = git_path("%s", pseudoref);
 170         fd = open(filename, O_WRONLY | O_CREAT, 0666);
 171         if (fd < 0)
 172                 die_errno(_("Could not open '%s' for writing"), filename);
 173         if (write_in_full(fd, buf.buf, buf.len) != buf.len || close(fd))
 174                 die_errno(_("Could not write to '%s'"), filename);
 175         strbuf_release(&buf);
 176 }
 177
 178 static void print_advice(int show_hint, struct replay_opts *opts)
 179 {
 180         char *msg = getenv("GIT_CHERRY_PICK_HELP");
 181
 182         if (msg) {
 183                 fprintf(stderr, "%s\n", msg);
 184                 /*
 185                  * A conflict has occurred but the porcelain
 186                  * (typically rebase --interactive) wants to take care
 187                  * of the commit itself so remove CHERRY_PICK_HEAD
 188                  */
 189                 unlink(git_path("CHERRY_PICK_HEAD"));
 190                 return;
 191         }
 192
 193         if (show_hint) {
 194                 if (opts->no_commit)
 195                         advise(_("after resolving the conflicts, mark the corrected paths\n"
 196                                  "with 'git add <paths>' or 'git rm <paths>'"));
 197                 else
 198                         advise(_("after resolving the conflicts, mark the corrected paths\n"
 199                                  "with 'git add <paths>' or 'git rm <paths>'\n"
 200                                  "and commit the result with 'git commit'"));
 201         }
 202 }
 203
 204 static void write_message(struct strbuf *msgbuf, const char *filename)
 205 {
 206         static struct lock_file msg_file;
 207
 208         int msg_fd = hold_lock_file_for_update(&msg_file, filename,
 209                                                LOCK_DIE_ON_ERROR);
 210         if (write_in_full(msg_fd, msgbuf->buf, msgbuf->len) < 0)
 211                 die_errno(_("Could not write to %s"), filename);
 212         strbuf_release(msgbuf);
 213         if (commit_lock_file(&msg_file) < 0)
 214                 die(_("Error wrapping up %s"), filename);
 215 }
 216
 217 static struct tree *empty_tree(void)
 218 {
 219         return lookup_tree(EMPTY_TREE_SHA1_BIN);
 220 }
 221
 222 static int error_dirty_index(struct replay_opts *opts)
 223 {
 224         if (read_cache_unmerged())
 225                 return error_resolve_conflict(action_name(opts));
 226
 227         /* Different translation strings for cherry-pick and revert */
 228         if (opts->action == REPLAY_PICK)
 229                 error(_("Your local changes would be overwritten by cherry-pick."));
 230         else
 231                 error(_("Your local changes would be overwritten by revert."));
 232
 233         if (advice_commit_before_merge)
 234                 advise(_("Commit your changes or stash them to proceed."));
 235         return -1;
 236 }
 237
 238 static int fast_forward_to(const unsigned char *to, const unsigned char *from,
 239                         int unborn, struct replay_opts *opts)
 240 {
 241         struct ref_transaction *transaction;
 242         struct strbuf sb = STRBUF_INIT;
 243         struct strbuf err = STRBUF_INIT;
 244
 245         read_cache();
 246         if (checkout_fast_forward(from, to, 1))
 247                 exit(128); /* the callee should have complained already */
 248
 249         strbuf_addf(&sb, "%s: fast-forward", action_name(opts));
 250
 251         transaction = ref_transaction_begin(&err);
 252         if (!transaction ||
 253             ref_transaction_update(transaction, "HEAD",
 254                                    to, unborn ? null_sha1 : from,
 255                                    0, sb.buf, &err) ||
 256             ref_transaction_commit(transaction, &err)) {
 257                 ref_transaction_free(transaction);
 258                 error("%s", err.buf);
 259                 strbuf_release(&sb);
 260                 strbuf_release(&err);
 261                 return -1;
 262         }
 263
 264         strbuf_release(&sb);
 265         strbuf_release(&err);
 266         ref_transaction_free(transaction);
 267         return 0;
 268 }
 269
 270 void append_conflicts_hint(struct strbuf *msgbuf)
 271 {
 272         int i;
 273
 274         strbuf_addch(msgbuf, '\n');
 275         strbuf_commented_addf(msgbuf, "Conflicts:\n");
 276         for (i = 0; i < active_nr;) {
 277                 const struct cache_entry *ce = active_cache[i++];
 278                 if (ce_stage(ce)) {
 279                         strbuf_commented_addf(msgbuf, "\t%s\n", ce->name);
 280                         while (i < active_nr && !strcmp(ce->name,
 281                                                         active_cache[i]->name))
 282                                 i++;
 283                 }
 284         }
 285 }
 286
 287 static int do_recursive_merge(struct commit *base, struct commit *next,
 288                               const char *base_label, const char *next_label,
 289                               unsigned char *head, struct strbuf *msgbuf,
 290                               struct replay_opts *opts)
 291 {
 292         struct merge_options o;
 293         struct tree *result, *next_tree, *base_tree, *head_tree;
 294         int clean;
 295         const char **xopt;
 296         static struct lock_file index_lock;
 297
 298         hold_locked_index(&index_lock, 1);
 299
 300         read_cache();
 301
 302         init_merge_options(&o);
 303         o.ancestor = base ? base_label : "(empty tree)";
 304         o.branch1 = "HEAD";
 305         o.branch2 = next ? next_label : "(empty tree)";
 306
 307         head_tree = parse_tree_indirect(head);
 308         next_tree = next ? next->tree : empty_tree();
 309         base_tree = base ? base->tree : empty_tree();
 310
 311         for (xopt = opts->xopts; xopt != opts->xopts + opts->xopts_nr; xopt++)
 312                 parse_merge_opt(&o, *xopt);
 313
 314         clean = merge_trees(&o,
 315                             head_tree,
 316                             next_tree, base_tree, &result);
 317
 318         if (active_cache_changed &&
 319             write_locked_index(&the_index, &index_lock, COMMIT_LOCK))
 320                 /* TRANSLATORS: %s will be "revert" or "cherry-pick" */
 321                 die(_("%s: Unable to write new index file"), action_name(opts));
 322         rollback_lock_file(&index_lock);
 323
 324         if (opts->signoff)
 325                 append_signoff(msgbuf, 0, 0);
 326
 327         if (!clean)
 328                 append_conflicts_hint(msgbuf);
 329
 330         return !clean;
 331 }
 332
 333 static int is_index_unchanged(void)
 334 {
 335         unsigned char head_sha1[20];
 336         struct commit *head_commit;
 337
 338         if (!resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, head_sha1, NULL))
 339                 return error(_("Could not resolve HEAD commit\n"));
 340
 341         head_commit = lookup_commit(head_sha1);
 342
 343         /*
 344          * If head_commit is NULL, check_commit, called from
 345          * lookup_commit, would have indicated that head_commit is not
 346          * a commit object already.  parse_commit() will return failure
 347          * without further complaints in such a case.  Otherwise, if
 348          * the commit is invalid, parse_commit() will complain.  So
 349          * there is nothing for us to say here.  Just return failure.
 350          */
 351         if (parse_commit(head_commit))
 352                 return -1;
 353
 354         if (!active_cache_tree)
 355                 active_cache_tree = cache_tree();
 356
 357         if (!cache_tree_fully_valid(active_cache_tree))
 358                 if (cache_tree_update(&the_index, 0))
 359                         return error(_("Unable to update cache tree\n"));
 360
 361         return !hashcmp(active_cache_tree->sha1, head_commit->tree->object.sha1);
 362 }
 363
 364 /*
 365  * If we are cherry-pick, and if the merge did not result in
 366  * hand-editing, we will hit this commit and inherit the original
 367  * author date and name.
 368  * If we are revert, or if our cherry-pick results in a hand merge,
 369  * we had better say that the current user is responsible for that.
 370  */
 371 static int run_git_commit(const char *defmsg, struct replay_opts *opts,
 372                           int allow_empty)
 373 {
 374         struct argv_array array;
 375         int rc;
 376         const char *value;
 377
 378         argv_array_init(&array);
 379         argv_array_push(&array, "commit");
 380         argv_array_push(&array, "-n");
 381
 382         if (opts->gpg_sign)
 383                 argv_array_pushf(&array, "-S%s", opts->gpg_sign);
 384         if (opts->signoff)
 385                 argv_array_push(&array, "-s");
 386         if (!opts->edit) {
 387                 argv_array_push(&array, "-F");
 388                 argv_array_push(&array, defmsg);
 389                 if (!opts->signoff &&
 390                     !opts->record_origin &&
 391                     git_config_get_value("commit.cleanup", &value))
 392                         argv_array_push(&array, "--cleanup=verbatim");
 393         }
 394
 395         if (allow_empty)
 396                 argv_array_push(&array, "--allow-empty");
 397
 398         if (opts->allow_empty_message)
 399                 argv_array_push(&array, "--allow-empty-message");
 400
 401         rc = run_command_v_opt(array.argv, RUN_GIT_CMD);
 402         argv_array_clear(&array);
 403         return rc;
 404 }
 405
 406 static int is_original_commit_empty(struct commit *commit)
 407 {
 408         const unsigned char *ptree_sha1;
 409
 410         if (parse_commit(commit))
 411                 return error(_("Could not parse commit %s\n"),
 412                              sha1_to_hex(commit->object.sha1));
 413         if (commit->parents) {
 414                 struct commit *parent = commit->parents->item;
 415                 if (parse_commit(parent))
 416                         return error(_("Could not parse parent commit %s\n"),
 417                                 sha1_to_hex(parent->object.sha1));
 418                 ptree_sha1 = parent->tree->object.sha1;
 419         } else {
 420                 ptree_sha1 = EMPTY_TREE_SHA1_BIN; /* commit is root */
 421         }
 422
 423         return !hashcmp(ptree_sha1, commit->tree->object.sha1);
 424 }
 425
 426 /*
 427  * Do we run "git commit" with "--allow-empty"?
 428  */
 429 static int allow_empty(struct replay_opts *opts, struct commit *commit)
 430 {
 431         int index_unchanged, empty_commit;
 432
 433         /*
 434          * Three cases:
 435          *
 436          * (1) we do not allow empty at all and error out.
 437          *
 438          * (2) we allow ones that were initially empty, but
 439          * forbid the ones that become empty;
 440          *
 441          * (3) we allow both.
 442          */
 443         if (!opts->allow_empty)
 444                 return 0; /* let "git commit" barf as necessary */
 445
 446         index_unchanged = is_index_unchanged();
 447         if (index_unchanged < 0)
 448                 return index_unchanged;
 449         if (!index_unchanged)
 450                 return 0; /* we do not have to say --allow-empty */
 451
 452         if (opts->keep_redundant_commits)
 453                 return 1;
 454
 455         empty_commit = is_original_commit_empty(commit);
 456         if (empty_commit < 0)
 457                 return empty_commit;
 458         if (!empty_commit)
 459                 return 0;
 460         else
 461                 return 1;
 462 }
 463
 464 static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
 465 {
 466         unsigned char head[20];
 467         struct commit *base, *next, *parent;
 468         const char *base_label, *next_label;
 469         struct commit_message msg = { NULL, NULL, NULL, NULL };
 470         char *defmsg = NULL;
 471         struct strbuf msgbuf = STRBUF_INIT;
 472         int res, unborn = 0, allow;
 473
 474         if (opts->no_commit) {
 475                 /*
 476                  * We do not intend to commit immediately.  We just want to
 477                  * merge the differences in, so let's compute the tree
 478                  * that represents the "current" state for merge-recursive
 479                  * to work on.
 480                  */
 481                 if (write_cache_as_tree(head, 0, NULL))
 482                         die (_("Your index file is unmerged."));
 483         } else {
 484                 unborn = get_sha1("HEAD", head);
 485                 if (unborn)
 486                         hashcpy(head, EMPTY_TREE_SHA1_BIN);
 487                 if (index_differs_from(unborn ? EMPTY_TREE_SHA1_HEX : "HEAD", 0))
 488                         return error_dirty_index(opts);
 489         }
 490         discard_cache();
 491
 492         if (!commit->parents) {
 493                 parent = NULL;
 494         }
 495         else if (commit->parents->next) {
 496                 /* Reverting or cherry-picking a merge commit */
 497                 int cnt;
 498                 struct commit_list *p;
 499
 500                 if (!opts->mainline)
 501                         return error(_("Commit %s is a merge but no -m option was given."),
 502                                 sha1_to_hex(commit->object.sha1));
 503
 504                 for (cnt = 1, p = commit->parents;
 505                      cnt != opts->mainline && p;
 506                      cnt++)
 507                         p = p->next;
 508                 if (cnt != opts->mainline || !p)
 509                         return error(_("Commit %s does not have parent %d"),
 510                                 sha1_to_hex(commit->object.sha1), opts->mainline);
 511                 parent = p->item;
 512         } else if (0 < opts->mainline)
 513                 return error(_("Mainline was specified but commit %s is not a merge."),
 514                         sha1_to_hex(commit->object.sha1));
 515         else
 516                 parent = commit->parents->item;
 517
 518         if (opts->allow_ff &&
 519             ((parent && !hashcmp(parent->object.sha1, head)) ||
 520              (!parent && unborn)))
 521                 return fast_forward_to(commit->object.sha1, head, unborn, opts);
 522
 523         if (parent && parse_commit(parent) < 0)
 524                 /* TRANSLATORS: The first %s will be "revert" or
 525                    "cherry-pick", the second %s a SHA1 */
 526                 return error(_("%s: cannot parse parent commit %s"),
 527                         action_name(opts), sha1_to_hex(parent->object.sha1));
 528
 529         if (get_message(commit, &msg) != 0)
 530                 return error(_("Cannot get commit message for %s"),
 531                         sha1_to_hex(commit->object.sha1));
 532
 533         /*
 534          * "commit" is an existing commit.  We would want to apply
 535          * the difference it introduces since its first parent "prev"
 536          * on top of the current HEAD if we are cherry-pick.  Or the
 537          * reverse of it if we are revert.
 538          */
 539
 540         defmsg = git_pathdup("MERGE_MSG");
 541
 542         if (opts->action == REPLAY_REVERT) {
 543                 base = commit;
 544                 base_label = msg.label;
 545                 next = parent;
 546                 next_label = msg.parent_label;
 547                 strbuf_addstr(&msgbuf, "Revert \"");
 548                 strbuf_addstr(&msgbuf, msg.subject);
 549                 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
 550                 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 551
 552                 if (commit->parents && commit->parents->next) {
 553                         strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
 554                         strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
 555                 }
 556                 strbuf_addstr(&msgbuf, ".\n");
 557         } else {
 558                 const char *p;
 559
 560                 base = parent;
 561                 base_label = msg.parent_label;
 562                 next = commit;
 563                 next_label = msg.label;
 564
 565                 /*
 566                  * Append the commit log message to msgbuf; it starts
 567                  * after the tree, parent, author, committer
 568                  * information followed by "\n\n".
 569                  */
 570                 p = strstr(msg.message, "\n\n");
 571                 if (p)
 572                         strbuf_addstr(&msgbuf, skip_blank_lines(p + 2));
 573
 574                 if (opts->record_origin) {
 575                         if (!has_conforming_footer(&msgbuf, NULL, 0))
 576                                 strbuf_addch(&msgbuf, '\n');
 577                         strbuf_addstr(&msgbuf, cherry_picked_prefix);
 578                         strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 579                         strbuf_addstr(&msgbuf, ")\n");
 580                 }
 581         }
 582
 583         if (!opts->strategy || !strcmp(opts->strategy, "recursive") || opts->action == REPLAY_REVERT) {
 584                 res = do_recursive_merge(base, next, base_label, next_label,
 585                                          head, &msgbuf, opts);
 586                 write_message(&msgbuf, defmsg);
 587         } else {
 588                 struct commit_list *common = NULL;
 589                 struct commit_list *remotes = NULL;
 590
 591                 write_message(&msgbuf, defmsg);
 592
 593                 commit_list_insert(base, &common);
 594                 commit_list_insert(next, &remotes);
 595                 res = try_merge_command(opts->strategy, opts->xopts_nr, opts->xopts,
 596                                         common, sha1_to_hex(head), remotes);
 597                 free_commit_list(common);
 598                 free_commit_list(remotes);
 599         }
 600
 601         /*
 602          * If the merge was clean or if it failed due to conflict, we write
 603          * CHERRY_PICK_HEAD for the subsequent invocation of commit to use.
 604          * However, if the merge did not even start, then we don't want to
 605          * write it at all.
 606          */
 607         if (opts->action == REPLAY_PICK && !opts->no_commit && (res == 0 || res == 1))
 608                 write_cherry_pick_head(commit, "CHERRY_PICK_HEAD");
 609         if (opts->action == REPLAY_REVERT && ((opts->no_commit && res == 0) || res == 1))
 610                 write_cherry_pick_head(commit, "REVERT_HEAD");
 611
 612         if (res) {
 613                 error(opts->action == REPLAY_REVERT
 614                       ? _("could not revert %s... %s")
 615                       : _("could not apply %s... %s"),
 616                       find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV),
 617                       msg.subject);
 618                 print_advice(res == 1, opts);
 619                 rerere(opts->allow_rerere_auto);
 620                 goto leave;
 621         }
 622
 623         allow = allow_empty(opts, commit);
 624         if (allow < 0) {
 625                 res = allow;
 626                 goto leave;
 627         }
 628         if (!opts->no_commit)
 629                 res = run_git_commit(defmsg, opts, allow);
 630
 631 leave:
 632         free_message(commit, &msg);
 633         free(defmsg);
 634
 635         return res;
 636 }
 637
 638 static void prepare_revs(struct replay_opts *opts)
 639 {
 640         /*
 641          * picking (but not reverting) ranges (but not individual revisions)
 642          * should be done in reverse
 643          */
 644         if (opts->action == REPLAY_PICK && !opts->revs->no_walk)
 645                 opts->revs->reverse ^= 1;
 646
 647         if (prepare_revision_walk(opts->revs))
 648                 die(_("revision walk setup failed"));
 649
 650         if (!opts->revs->commits)
 651                 die(_("empty commit set passed"));
 652 }
 653
 654 static void read_and_refresh_cache(struct replay_opts *opts)
 655 {
 656         static struct lock_file index_lock;
 657         int index_fd = hold_locked_index(&index_lock, 0);
 658         if (read_index_preload(&the_index, NULL) < 0)
 659                 die(_("git %s: failed to read the index"), action_name(opts));
 660         refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
 661         if (the_index.cache_changed && index_fd >= 0) {
 662                 if (write_locked_index(&the_index, &index_lock, COMMIT_LOCK))
 663                         die(_("git %s: failed to refresh the index"), action_name(opts));
 664         }
 665         rollback_lock_file(&index_lock);
 666 }
 667
 668 static int format_todo(struct strbuf *buf, struct commit_list *todo_list,
 669                 struct replay_opts *opts)
 670 {
 671         struct commit_list *cur = NULL;
 672         const char *sha1_abbrev = NULL;
 673         const char *action_str = opts->action == REPLAY_REVERT ? "revert" : "pick";
 674         const char *subject;
 675         int subject_len;
 676
 677         for (cur = todo_list; cur; cur = cur->next) {
 678                 const char *commit_buffer = get_commit_buffer(cur->item, NULL);
 679                 sha1_abbrev = find_unique_abbrev(cur->item->object.sha1, DEFAULT_ABBREV);
 680                 subject_len = find_commit_subject(commit_buffer, &subject);
 681                 strbuf_addf(buf, "%s %s %.*s\n", action_str, sha1_abbrev,
 682                         subject_len, subject);
 683                 unuse_commit_buffer(cur->item, commit_buffer);
 684         }
 685         return 0;
 686 }
 687
 688 static struct commit *parse_insn_line(char *bol, char *eol, struct replay_opts *opts)
 689 {
 690         unsigned char commit_sha1[20];
 691         enum replay_action action;
 692         char *end_of_object_name;
 693         int saved, status, padding;
 694
 695         if (starts_with(bol, "pick")) {
 696                 action = REPLAY_PICK;
 697                 bol += strlen("pick");
 698         } else if (starts_with(bol, "revert")) {
 699                 action = REPLAY_REVERT;
 700                 bol += strlen("revert");
 701         } else
 702                 return NULL;
 703
 704         /* Eat up extra spaces/ tabs before object name */
 705         padding = strspn(bol, " \t");
 706         if (!padding)
 707                 return NULL;
 708         bol += padding;
 709
 710         end_of_object_name = bol + strcspn(bol, " \t\n");
 711         saved = *end_of_object_name;
 712         *end_of_object_name = '\0';
 713         status = get_sha1(bol, commit_sha1);
 714         *end_of_object_name = saved;
 715
 716         /*
 717          * Verify that the action matches up with the one in
 718          * opts; we don't support arbitrary instructions
 719          */
 720         if (action != opts->action) {
 721                 const char *action_str;
 722                 action_str = action == REPLAY_REVERT ? "revert" : "cherry-pick";
 723                 error(_("Cannot %s during a %s"), action_str, action_name(opts));
 724                 return NULL;
 725         }
 726
 727         if (status < 0)
 728                 return NULL;
 729
 730         return lookup_commit_reference(commit_sha1);
 731 }
 732
 733 static int parse_insn_buffer(char *buf, struct commit_list **todo_list,
 734                         struct replay_opts *opts)
 735 {
 736         struct commit_list **next = todo_list;
 737         struct commit *commit;
 738         char *p = buf;
 739         int i;
 740
 741         for (i = 1; *p; i++) {
 742                 char *eol = strchrnul(p, '\n');
 743                 commit = parse_insn_line(p, eol, opts);
 744                 if (!commit)
 745                         return error(_("Could not parse line %d."), i);
 746                 next = commit_list_append(commit, next);
 747                 p = *eol ? eol + 1 : eol;
 748         }
 749         if (!*todo_list)
 750                 return error(_("No commits parsed."));
 751         return 0;
 752 }
 753
 754 static void read_populate_todo(struct commit_list **todo_list,
 755                         struct replay_opts *opts)
 756 {
 757         const char *todo_file = git_path(SEQ_TODO_FILE);
 758         struct strbuf buf = STRBUF_INIT;
 759         int fd, res;
 760
 761         fd = open(todo_file, O_RDONLY);
 762         if (fd < 0)
 763                 die_errno(_("Could not open %s"), todo_file);
 764         if (strbuf_read(&buf, fd, 0) < 0) {
 765                 close(fd);
 766                 strbuf_release(&buf);
 767                 die(_("Could not read %s."), todo_file);
 768         }
 769         close(fd);
 770
 771         res = parse_insn_buffer(buf.buf, todo_list, opts);
 772         strbuf_release(&buf);
 773         if (res)
 774                 die(_("Unusable instruction sheet: %s"), todo_file);
 775 }
 776
 777 static int populate_opts_cb(const char *key, const char *value, void *data)
 778 {
 779         struct replay_opts *opts = data;
 780         int error_flag = 1;
 781
 782         if (!value)
 783                 error_flag = 0;
 784         else if (!strcmp(key, "options.no-commit"))
 785                 opts->no_commit = git_config_bool_or_int(key, value, &error_flag);
 786         else if (!strcmp(key, "options.edit"))
 787                 opts->edit = git_config_bool_or_int(key, value, &error_flag);
 788         else if (!strcmp(key, "options.signoff"))
 789                 opts->signoff = git_config_bool_or_int(key, value, &error_flag);
 790         else if (!strcmp(key, "options.record-origin"))
 791                 opts->record_origin = git_config_bool_or_int(key, value, &error_flag);
 792         else if (!strcmp(key, "options.allow-ff"))
 793                 opts->allow_ff = git_config_bool_or_int(key, value, &error_flag);
 794         else if (!strcmp(key, "options.mainline"))
 795                 opts->mainline = git_config_int(key, value);
 796         else if (!strcmp(key, "options.strategy"))
 797                 git_config_string(&opts->strategy, key, value);
 798         else if (!strcmp(key, "options.gpg-sign"))
 799                 git_config_string(&opts->gpg_sign, key, value);
 800         else if (!strcmp(key, "options.strategy-option")) {
 801                 ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
 802                 opts->xopts[opts->xopts_nr++] = xstrdup(value);
 803         } else
 804                 return error(_("Invalid key: %s"), key);
 805
 806         if (!error_flag)
 807                 return error(_("Invalid value for %s: %s"), key, value);
 808
 809         return 0;
 810 }
 811
 812 static void read_populate_opts(struct replay_opts **opts_ptr)
 813 {
 814         const char *opts_file = git_path(SEQ_OPTS_FILE);
 815
 816         if (!file_exists(opts_file))
 817                 return;
 818         if (git_config_from_file(populate_opts_cb, opts_file, *opts_ptr) < 0)
 819                 die(_("Malformed options sheet: %s"), opts_file);
 820 }
 821
 822 static void walk_revs_populate_todo(struct commit_list **todo_list,
 823                                 struct replay_opts *opts)
 824 {
 825         struct commit *commit;
 826         struct commit_list **next;
 827
 828         prepare_revs(opts);
 829
 830         next = todo_list;
 831         while ((commit = get_revision(opts->revs)))
 832                 next = commit_list_append(commit, next);
 833 }
 834
 835 static int create_seq_dir(void)
 836 {
 837         const char *seq_dir = git_path(SEQ_DIR);
 838
 839         if (file_exists(seq_dir)) {
 840                 error(_("a cherry-pick or revert is already in progress"));
 841                 advise(_("try \"git cherry-pick (--continue | --quit | --abort)\""));
 842                 return -1;
 843         }
 844         else if (mkdir(seq_dir, 0777) < 0)
 845                 die_errno(_("Could not create sequencer directory %s"), seq_dir);
 846         return 0;
 847 }
 848
 849 static void save_head(const char *head)
 850 {
 851         const char *head_file = git_path(SEQ_HEAD_FILE);
 852         static struct lock_file head_lock;
 853         struct strbuf buf = STRBUF_INIT;
 854         int fd;
 855
 856         fd = hold_lock_file_for_update(&head_lock, head_file, LOCK_DIE_ON_ERROR);
 857         strbuf_addf(&buf, "%s\n", head);
 858         if (write_in_full(fd, buf.buf, buf.len) < 0)
 859                 die_errno(_("Could not write to %s"), head_file);
 860         if (commit_lock_file(&head_lock) < 0)
 861                 die(_("Error wrapping up %s."), head_file);
 862 }
 863
 864 static int reset_for_rollback(const unsigned char *sha1)
 865 {
 866         const char *argv[4];    /* reset --merge <arg> + NULL */
 867         argv[0] = "reset";
 868         argv[1] = "--merge";
 869         argv[2] = sha1_to_hex(sha1);
 870         argv[3] = NULL;
 871         return run_command_v_opt(argv, RUN_GIT_CMD);
 872 }
 873
 874 static int rollback_single_pick(void)
 875 {
 876         unsigned char head_sha1[20];
 877
 878         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
 879             !file_exists(git_path("REVERT_HEAD")))
 880                 return error(_("no cherry-pick or revert in progress"));
 881         if (read_ref_full("HEAD", 0, head_sha1, NULL))
 882                 return error(_("cannot resolve HEAD"));
 883         if (is_null_sha1(head_sha1))
 884                 return error(_("cannot abort from a branch yet to be born"));
 885         return reset_for_rollback(head_sha1);
 886 }
 887
 888 static int sequencer_rollback(struct replay_opts *opts)
 889 {
 890         const char *filename;
 891         FILE *f;
 892         unsigned char sha1[20];
 893         struct strbuf buf = STRBUF_INIT;
 894
 895         filename = git_path(SEQ_HEAD_FILE);
 896         f = fopen(filename, "r");
 897         if (!f && errno == ENOENT) {
 898                 /*
 899                  * There is no multiple-cherry-pick in progress.
 900                  * If CHERRY_PICK_HEAD or REVERT_HEAD indicates
 901                  * a single-cherry-pick in progress, abort that.
 902                  */
 903                 return rollback_single_pick();
 904         }
 905         if (!f)
 906                 return error(_("cannot open %s: %s"), filename,
 907                                                 strerror(errno));
 908         if (strbuf_getline(&buf, f, '\n')) {
 909                 error(_("cannot read %s: %s"), filename, ferror(f) ?
 910                         strerror(errno) : _("unexpected end of file"));
 911                 fclose(f);
 912                 goto fail;
 913         }
 914         fclose(f);
 915         if (get_sha1_hex(buf.buf, sha1) || buf.buf[40] != '\0') {
 916                 error(_("stored pre-cherry-pick HEAD file '%s' is corrupt"),
 917                         filename);
 918                 goto fail;
 919         }
 920         if (reset_for_rollback(sha1))
 921                 goto fail;
 922         remove_sequencer_state();
 923         strbuf_release(&buf);
 924         return 0;
 925 fail:
 926         strbuf_release(&buf);
 927         return -1;
 928 }
 929
 930 static void save_todo(struct commit_list *todo_list, struct replay_opts *opts)
 931 {
 932         const char *todo_file = git_path(SEQ_TODO_FILE);
 933         static struct lock_file todo_lock;
 934         struct strbuf buf = STRBUF_INIT;
 935         int fd;
 936
 937         fd = hold_lock_file_for_update(&todo_lock, todo_file, LOCK_DIE_ON_ERROR);
 938         if (format_todo(&buf, todo_list, opts) < 0)
 939                 die(_("Could not format %s."), todo_file);
 940         if (write_in_full(fd, buf.buf, buf.len) < 0) {
 941                 strbuf_release(&buf);
 942                 die_errno(_("Could not write to %s"), todo_file);
 943         }
 944         if (commit_lock_file(&todo_lock) < 0) {
 945                 strbuf_release(&buf);
 946                 die(_("Error wrapping up %s."), todo_file);
 947         }
 948         strbuf_release(&buf);
 949 }
 950
 951 static void save_opts(struct replay_opts *opts)
 952 {
 953         const char *opts_file = git_path(SEQ_OPTS_FILE);
 954
 955         if (opts->no_commit)
 956                 git_config_set_in_file(opts_file, "options.no-commit", "true");
 957         if (opts->edit)
 958                 git_config_set_in_file(opts_file, "options.edit", "true");
 959         if (opts->signoff)
 960                 git_config_set_in_file(opts_file, "options.signoff", "true");
 961         if (opts->record_origin)
 962                 git_config_set_in_file(opts_file, "options.record-origin", "true");
 963         if (opts->allow_ff)
 964                 git_config_set_in_file(opts_file, "options.allow-ff", "true");
 965         if (opts->mainline) {
 966                 struct strbuf buf = STRBUF_INIT;
 967                 strbuf_addf(&buf, "%d", opts->mainline);
 968                 git_config_set_in_file(opts_file, "options.mainline", buf.buf);
 969                 strbuf_release(&buf);
 970         }
 971         if (opts->strategy)
 972                 git_config_set_in_file(opts_file, "options.strategy", opts->strategy);
 973         if (opts->gpg_sign)
 974                 git_config_set_in_file(opts_file, "options.gpg-sign", opts->gpg_sign);
 975         if (opts->xopts) {
 976                 int i;
 977                 for (i = 0; i < opts->xopts_nr; i++)
 978                         git_config_set_multivar_in_file(opts_file,
 979                                                         "options.strategy-option",
 980                                                         opts->xopts[i], "^$", 0);
 981         }
 982 }
 983
 984 static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
 985 {
 986         struct commit_list *cur;
 987         int res;
 988
 989         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
 990         if (opts->allow_ff)
 991                 assert(!(opts->signoff || opts->no_commit ||
 992                                 opts->record_origin || opts->edit));
 993         read_and_refresh_cache(opts);
 994
 995         for (cur = todo_list; cur; cur = cur->next) {
 996                 save_todo(cur, opts);
 997                 res = do_pick_commit(cur->item, opts);
 998                 if (res)
 999                         return res;
1000         }
1001
1002         /*
1003          * Sequence of picks finished successfully; cleanup by
1004          * removing the .git/sequencer directory
1005          */
1006         remove_sequencer_state();
1007         return 0;
1008 }
1009
1010 static int continue_single_pick(void)
1011 {
1012         const char *argv[] = { "commit", NULL };
1013
1014         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
1015             !file_exists(git_path("REVERT_HEAD")))
1016                 return error(_("no cherry-pick or revert in progress"));
1017         return run_command_v_opt(argv, RUN_GIT_CMD);
1018 }
1019
1020 static int sequencer_continue(struct replay_opts *opts)
1021 {
1022         struct commit_list *todo_list = NULL;
1023
1024         if (!file_exists(git_path(SEQ_TODO_FILE)))
1025                 return continue_single_pick();
1026         read_populate_opts(&opts);
1027         read_populate_todo(&todo_list, opts);
1028
1029         /* Verify that the conflict has been resolved */
1030         if (file_exists(git_path("CHERRY_PICK_HEAD")) ||
1031             file_exists(git_path("REVERT_HEAD"))) {
1032                 int ret = continue_single_pick();
1033                 if (ret)
1034                         return ret;
1035         }
1036         if (index_differs_from("HEAD", 0))
1037                 return error_dirty_index(opts);
1038         todo_list = todo_list->next;
1039         return pick_commits(todo_list, opts);
1040 }
1041
1042 static int single_pick(struct commit *cmit, struct replay_opts *opts)
1043 {
1044         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
1045         return do_pick_commit(cmit, opts);
1046 }
1047
1048 int sequencer_pick_revisions(struct replay_opts *opts)
1049 {
1050         struct commit_list *todo_list = NULL;
1051         unsigned char sha1[20];
1052         int i;
1053
1054         if (opts->subcommand == REPLAY_NONE)
1055                 assert(opts->revs);
1056
1057         read_and_refresh_cache(opts);
1058
1059         /*
1060          * Decide what to do depending on the arguments; a fresh
1061          * cherry-pick should be handled differently from an existing
1062          * one that is being continued
1063          */
1064         if (opts->subcommand == REPLAY_REMOVE_STATE) {
1065                 remove_sequencer_state();
1066                 return 0;
1067         }
1068         if (opts->subcommand == REPLAY_ROLLBACK)
1069                 return sequencer_rollback(opts);
1070         if (opts->subcommand == REPLAY_CONTINUE)
1071                 return sequencer_continue(opts);
1072
1073         for (i = 0; i < opts->revs->pending.nr; i++) {
1074                 unsigned char sha1[20];
1075                 const char *name = opts->revs->pending.objects[i].name;
1076
1077                 /* This happens when using --stdin. */
1078                 if (!strlen(name))
1079                         continue;
1080
1081                 if (!get_sha1(name, sha1)) {
1082                         if (!lookup_commit_reference_gently(sha1, 1)) {
1083                                 enum object_type type = sha1_object_info(sha1, NULL);
1084                                 die(_("%s: can't cherry-pick a %s"), name, typename(type));
1085                         }
1086                 } else
1087                         die(_("%s: bad revision"), name);
1088         }
1089
1090         /*
1091          * If we were called as "git cherry-pick <commit>", just
1092          * cherry-pick/revert it, set CHERRY_PICK_HEAD /
1093          * REVERT_HEAD, and don't touch the sequencer state.
1094          * This means it is possible to cherry-pick in the middle
1095          * of a cherry-pick sequence.
1096          */
1097         if (opts->revs->cmdline.nr == 1 &&
1098             opts->revs->cmdline.rev->whence == REV_CMD_REV &&
1099             opts->revs->no_walk &&
1100             !opts->revs->cmdline.rev->flags) {
1101                 struct commit *cmit;
1102                 if (prepare_revision_walk(opts->revs))
1103                         die(_("revision walk setup failed"));
1104                 cmit = get_revision(opts->revs);
1105                 if (!cmit || get_revision(opts->revs))
1106                         die("BUG: expected exactly one commit from walk");
1107                 return single_pick(cmit, opts);
1108         }
1109
1110         /*
1111          * Start a new cherry-pick/ revert sequence; but
1112          * first, make sure that an existing one isn't in
1113          * progress
1114          */
1115
1116         walk_revs_populate_todo(&todo_list, opts);
1117         if (create_seq_dir() < 0)
1118                 return -1;
1119         if (get_sha1("HEAD", sha1)) {
1120                 if (opts->action == REPLAY_REVERT)
1121                         return error(_("Can't revert as initial commit"));
1122                 return error(_("Can't cherry-pick into empty head"));
1123         }
1124         save_head(sha1_to_hex(sha1));
1125         save_opts(opts);
1126         return pick_commits(todo_list, opts);
1127 }
1128
1129 void append_signoff(struct strbuf *msgbuf, int ignore_footer, unsigned flag)
1130 {
1131         unsigned no_dup_sob = flag & APPEND_SIGNOFF_DEDUP;
1132         struct strbuf sob = STRBUF_INIT;
1133         int has_footer;
1134
1135         strbuf_addstr(&sob, sign_off_header);
1136         strbuf_addstr(&sob, fmt_name(getenv("GIT_COMMITTER_NAME"),
1137                                 getenv("GIT_COMMITTER_EMAIL")));
1138         strbuf_addch(&sob, '\n');
1139
1140         /*
1141          * If the whole message buffer is equal to the sob, pretend that we
1142          * found a conforming footer with a matching sob
1143          */
1144         if (msgbuf->len - ignore_footer == sob.len &&
1145             !strncmp(msgbuf->buf, sob.buf, sob.len))
1146                 has_footer = 3;
1147         else
1148                 has_footer = has_conforming_footer(msgbuf, &sob, ignore_footer);
1149
1150         if (!has_footer) {
1151                 const char *append_newlines = NULL;
1152                 size_t len = msgbuf->len - ignore_footer;
1153
1154                 if (!len) {
1155                         /*
1156                          * The buffer is completely empty.  Leave foom for
1157                          * the title and body to be filled in by the user.
1158                          */
1159                         append_newlines = "\n\n";
1160                 } else if (msgbuf->buf[len - 1] != '\n') {
1161                         /*
1162                          * Incomplete line.  Complete the line and add a
1163                          * blank one so that there is an empty line between
1164                          * the message body and the sob.
1165                          */
1166                         append_newlines = "\n\n";
1167                 } else if (len == 1) {
1168                         /*
1169                          * Buffer contains a single newline.  Add another
1170                          * so that we leave room for the title and body.
1171                          */
1172                         append_newlines = "\n";
1173                 } else if (msgbuf->buf[len - 2] != '\n') {
1174                         /*
1175                          * Buffer ends with a single newline.  Add another
1176                          * so that there is an empty line between the message
1177                          * body and the sob.
1178                          */
1179                         append_newlines = "\n";
1180                 } /* else, the buffer already ends with two newlines. */
1181
1182                 if (append_newlines)
1183                         strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0,
1184                                 append_newlines, strlen(append_newlines));
1185         }
1186
1187         if (has_footer != 3 && (!no_dup_sob || has_footer != 2))
1188                 strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0,
1189                                 sob.buf, sob.len);
1190
1191         strbuf_release(&sob);
1192 }