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

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