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, index_fd;
 267         const char **xopt;
 268         static struct lock_file index_lock;
 269
 270         index_fd = 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_cache(index_fd, active_cache, active_nr) ||
 292              commit_locked_index(&index_lock)))
 293                 /* TRANSLATORS: %s will be "revert" or "cherry-pick" */
 294                 die(_("%s: Unable to write new index file"), action_name(opts));
 295         rollback_lock_file(&index_lock);
 296
 297         if (opts->signoff)
 298                 append_signoff(msgbuf, 0, 0);
 299
 300         if (!clean) {
 301                 int i;
 302                 strbuf_addstr(msgbuf, "\nConflicts:\n");
 303                 for (i = 0; i < active_nr;) {
 304                         const struct cache_entry *ce = active_cache[i++];
 305                         if (ce_stage(ce)) {
 306                                 strbuf_addch(msgbuf, '\t');
 307                                 strbuf_addstr(msgbuf, ce->name);
 308                                 strbuf_addch(msgbuf, '\n');
 309                                 while (i < active_nr && !strcmp(ce->name,
 310                                                 active_cache[i]->name))
 311                                         i++;
 312                         }
 313                 }
 314         }
 315
 316         return !clean;
 317 }
 318
 319 static int is_index_unchanged(void)
 320 {
 321         unsigned char head_sha1[20];
 322         struct commit *head_commit;
 323
 324         if (!resolve_ref_unsafe("HEAD", head_sha1, 1, NULL))
 325                 return error(_("Could not resolve HEAD commit\n"));
 326
 327         head_commit = lookup_commit(head_sha1);
 328
 329         /*
 330          * If head_commit is NULL, check_commit, called from
 331          * lookup_commit, would have indicated that head_commit is not
 332          * a commit object already.  parse_commit() will return failure
 333          * without further complaints in such a case.  Otherwise, if
 334          * the commit is invalid, parse_commit() will complain.  So
 335          * there is nothing for us to say here.  Just return failure.
 336          */
 337         if (parse_commit(head_commit))
 338                 return -1;
 339
 340         if (!active_cache_tree)
 341                 active_cache_tree = cache_tree();
 342
 343         if (!cache_tree_fully_valid(active_cache_tree))
 344                 if (cache_tree_update(active_cache_tree,
 345                                       (const struct cache_entry * const *)active_cache,
 346                                       active_nr, 0))
 347                         return error(_("Unable to update cache tree\n"));
 348
 349         return !hashcmp(active_cache_tree->sha1, head_commit->tree->object.sha1);
 350 }
 351
 352 /*
 353  * If we are cherry-pick, and if the merge did not result in
 354  * hand-editing, we will hit this commit and inherit the original
 355  * author date and name.
 356  * If we are revert, or if our cherry-pick results in a hand merge,
 357  * we had better say that the current user is responsible for that.
 358  */
 359 static int run_git_commit(const char *defmsg, struct replay_opts *opts,
 360                           int allow_empty)
 361 {
 362         struct argv_array array;
 363         int rc;
 364         char *gpg_sign;
 365
 366         argv_array_init(&array);
 367         argv_array_push(&array, "commit");
 368         argv_array_push(&array, "-n");
 369
 370         if (opts->gpg_sign) {
 371                 gpg_sign = xmalloc(3 + strlen(opts->gpg_sign));
 372                 sprintf(gpg_sign, "-S%s", opts->gpg_sign);
 373                 argv_array_push(&array, gpg_sign);
 374                 free(gpg_sign);
 375         }
 376         if (opts->signoff)
 377                 argv_array_push(&array, "-s");
 378         if (!opts->edit) {
 379                 argv_array_push(&array, "-F");
 380                 argv_array_push(&array, defmsg);
 381         }
 382
 383         if (allow_empty)
 384                 argv_array_push(&array, "--allow-empty");
 385
 386         if (opts->allow_empty_message)
 387                 argv_array_push(&array, "--allow-empty-message");
 388
 389         rc = run_command_v_opt(array.argv, RUN_GIT_CMD);
 390         argv_array_clear(&array);
 391         return rc;
 392 }
 393
 394 static int is_original_commit_empty(struct commit *commit)
 395 {
 396         const unsigned char *ptree_sha1;
 397
 398         if (parse_commit(commit))
 399                 return error(_("Could not parse commit %s\n"),
 400                              sha1_to_hex(commit->object.sha1));
 401         if (commit->parents) {
 402                 struct commit *parent = commit->parents->item;
 403                 if (parse_commit(parent))
 404                         return error(_("Could not parse parent commit %s\n"),
 405                                 sha1_to_hex(parent->object.sha1));
 406                 ptree_sha1 = parent->tree->object.sha1;
 407         } else {
 408                 ptree_sha1 = EMPTY_TREE_SHA1_BIN; /* commit is root */
 409         }
 410
 411         return !hashcmp(ptree_sha1, commit->tree->object.sha1);
 412 }
 413
 414 /*
 415  * Do we run "git commit" with "--allow-empty"?
 416  */
 417 static int allow_empty(struct replay_opts *opts, struct commit *commit)
 418 {
 419         int index_unchanged, empty_commit;
 420
 421         /*
 422          * Three cases:
 423          *
 424          * (1) we do not allow empty at all and error out.
 425          *
 426          * (2) we allow ones that were initially empty, but
 427          * forbid the ones that become empty;
 428          *
 429          * (3) we allow both.
 430          */
 431         if (!opts->allow_empty)
 432                 return 0; /* let "git commit" barf as necessary */
 433
 434         index_unchanged = is_index_unchanged();
 435         if (index_unchanged < 0)
 436                 return index_unchanged;
 437         if (!index_unchanged)
 438                 return 0; /* we do not have to say --allow-empty */
 439
 440         if (opts->keep_redundant_commits)
 441                 return 1;
 442
 443         empty_commit = is_original_commit_empty(commit);
 444         if (empty_commit < 0)
 445                 return empty_commit;
 446         if (!empty_commit)
 447                 return 0;
 448         else
 449                 return 1;
 450 }
 451
 452 static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
 453 {
 454         unsigned char head[20];
 455         struct commit *base, *next, *parent;
 456         const char *base_label, *next_label;
 457         struct commit_message msg = { NULL, NULL, NULL, NULL };
 458         char *defmsg = NULL;
 459         struct strbuf msgbuf = STRBUF_INIT;
 460         int res, unborn = 0, allow;
 461
 462         if (opts->no_commit) {
 463                 /*
 464                  * We do not intend to commit immediately.  We just want to
 465                  * merge the differences in, so let's compute the tree
 466                  * that represents the "current" state for merge-recursive
 467                  * to work on.
 468                  */
 469                 if (write_cache_as_tree(head, 0, NULL))
 470                         die (_("Your index file is unmerged."));
 471         } else {
 472                 unborn = get_sha1("HEAD", head);
 473                 if (unborn)
 474                         hashcpy(head, EMPTY_TREE_SHA1_BIN);
 475                 if (index_differs_from(unborn ? EMPTY_TREE_SHA1_HEX : "HEAD", 0))
 476                         return error_dirty_index(opts);
 477         }
 478         discard_cache();
 479
 480         if (!commit->parents) {
 481                 parent = NULL;
 482         }
 483         else if (commit->parents->next) {
 484                 /* Reverting or cherry-picking a merge commit */
 485                 int cnt;
 486                 struct commit_list *p;
 487
 488                 if (!opts->mainline)
 489                         return error(_("Commit %s is a merge but no -m option was given."),
 490                                 sha1_to_hex(commit->object.sha1));
 491
 492                 for (cnt = 1, p = commit->parents;
 493                      cnt != opts->mainline && p;
 494                      cnt++)
 495                         p = p->next;
 496                 if (cnt != opts->mainline || !p)
 497                         return error(_("Commit %s does not have parent %d"),
 498                                 sha1_to_hex(commit->object.sha1), opts->mainline);
 499                 parent = p->item;
 500         } else if (0 < opts->mainline)
 501                 return error(_("Mainline was specified but commit %s is not a merge."),
 502                         sha1_to_hex(commit->object.sha1));
 503         else
 504                 parent = commit->parents->item;
 505
 506         if (opts->allow_ff &&
 507             ((parent && !hashcmp(parent->object.sha1, head)) ||
 508              (!parent && unborn)))
 509                 return fast_forward_to(commit->object.sha1, head, unborn, opts);
 510
 511         if (parent && parse_commit(parent) < 0)
 512                 /* TRANSLATORS: The first %s will be "revert" or
 513                    "cherry-pick", the second %s a SHA1 */
 514                 return error(_("%s: cannot parse parent commit %s"),
 515                         action_name(opts), sha1_to_hex(parent->object.sha1));
 516
 517         if (get_message(commit, &msg) != 0)
 518                 return error(_("Cannot get commit message for %s"),
 519                         sha1_to_hex(commit->object.sha1));
 520
 521         /*
 522          * "commit" is an existing commit.  We would want to apply
 523          * the difference it introduces since its first parent "prev"
 524          * on top of the current HEAD if we are cherry-pick.  Or the
 525          * reverse of it if we are revert.
 526          */
 527
 528         defmsg = git_pathdup("MERGE_MSG");
 529
 530         if (opts->action == REPLAY_REVERT) {
 531                 base = commit;
 532                 base_label = msg.label;
 533                 next = parent;
 534                 next_label = msg.parent_label;
 535                 strbuf_addstr(&msgbuf, "Revert \"");
 536                 strbuf_addstr(&msgbuf, msg.subject);
 537                 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
 538                 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 539
 540                 if (commit->parents && commit->parents->next) {
 541                         strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
 542                         strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
 543                 }
 544                 strbuf_addstr(&msgbuf, ".\n");
 545         } else {
 546                 const char *p;
 547
 548                 base = parent;
 549                 base_label = msg.parent_label;
 550                 next = commit;
 551                 next_label = msg.label;
 552
 553                 /*
 554                  * Append the commit log message to msgbuf; it starts
 555                  * after the tree, parent, author, committer
 556                  * information followed by "\n\n".
 557                  */
 558                 p = strstr(msg.message, "\n\n");
 559                 if (p) {
 560                         p += 2;
 561                         strbuf_addstr(&msgbuf, p);
 562                 }
 563
 564                 if (opts->record_origin) {
 565                         if (!has_conforming_footer(&msgbuf, NULL, 0))
 566                                 strbuf_addch(&msgbuf, '\n');
 567                         strbuf_addstr(&msgbuf, cherry_picked_prefix);
 568                         strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 569                         strbuf_addstr(&msgbuf, ")\n");
 570                 }
 571         }
 572
 573         if (!opts->strategy || !strcmp(opts->strategy, "recursive") || opts->action == REPLAY_REVERT) {
 574                 res = do_recursive_merge(base, next, base_label, next_label,
 575                                          head, &msgbuf, opts);
 576                 write_message(&msgbuf, defmsg);
 577         } else {
 578                 struct commit_list *common = NULL;
 579                 struct commit_list *remotes = NULL;
 580
 581                 write_message(&msgbuf, defmsg);
 582
 583                 commit_list_insert(base, &common);
 584                 commit_list_insert(next, &remotes);
 585                 res = try_merge_command(opts->strategy, opts->xopts_nr, opts->xopts,
 586                                         common, sha1_to_hex(head), remotes);
 587                 free_commit_list(common);
 588                 free_commit_list(remotes);
 589         }
 590
 591         /*
 592          * If the merge was clean or if it failed due to conflict, we write
 593          * CHERRY_PICK_HEAD for the subsequent invocation of commit to use.
 594          * However, if the merge did not even start, then we don't want to
 595          * write it at all.
 596          */
 597         if (opts->action == REPLAY_PICK && !opts->no_commit && (res == 0 || res == 1))
 598                 write_cherry_pick_head(commit, "CHERRY_PICK_HEAD");
 599         if (opts->action == REPLAY_REVERT && ((opts->no_commit && res == 0) || res == 1))
 600                 write_cherry_pick_head(commit, "REVERT_HEAD");
 601
 602         if (res) {
 603                 error(opts->action == REPLAY_REVERT
 604                       ? _("could not revert %s... %s")
 605                       : _("could not apply %s... %s"),
 606                       find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV),
 607                       msg.subject);
 608                 print_advice(res == 1, opts);
 609                 rerere(opts->allow_rerere_auto);
 610                 goto leave;
 611         }
 612
 613         allow = allow_empty(opts, commit);
 614         if (allow < 0) {
 615                 res = allow;
 616                 goto leave;
 617         }
 618         if (!opts->no_commit)
 619                 res = run_git_commit(defmsg, opts, allow);
 620
 621 leave:
 622         free_message(commit, &msg);
 623         free(defmsg);
 624
 625         return res;
 626 }
 627
 628 static void prepare_revs(struct replay_opts *opts)
 629 {
 630         /*
 631          * picking (but not reverting) ranges (but not individual revisions)
 632          * should be done in reverse
 633          */
 634         if (opts->action == REPLAY_PICK && !opts->revs->no_walk)
 635                 opts->revs->reverse ^= 1;
 636
 637         if (prepare_revision_walk(opts->revs))
 638                 die(_("revision walk setup failed"));
 639
 640         if (!opts->revs->commits)
 641                 die(_("empty commit set passed"));
 642 }
 643
 644 static void read_and_refresh_cache(struct replay_opts *opts)
 645 {
 646         static struct lock_file index_lock;
 647         int index_fd = hold_locked_index(&index_lock, 0);
 648         if (read_index_preload(&the_index, NULL) < 0)
 649                 die(_("git %s: failed to read the index"), action_name(opts));
 650         refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
 651         if (the_index.cache_changed) {
 652                 if (write_index(&the_index, index_fd) ||
 653                     commit_locked_index(&index_lock))
 654                         die(_("git %s: failed to refresh the index"), action_name(opts));
 655         }
 656         rollback_lock_file(&index_lock);
 657 }
 658
 659 static int format_todo(struct strbuf *buf, struct commit_list *todo_list,
 660                 struct replay_opts *opts)
 661 {
 662         struct commit_list *cur = NULL;
 663         const char *sha1_abbrev = NULL;
 664         const char *action_str = opts->action == REPLAY_REVERT ? "revert" : "pick";
 665         const char *subject;
 666         int subject_len;
 667
 668         for (cur = todo_list; cur; cur = cur->next) {
 669                 const char *commit_buffer = get_commit_buffer(cur->item, NULL);
 670                 sha1_abbrev = find_unique_abbrev(cur->item->object.sha1, DEFAULT_ABBREV);
 671                 subject_len = find_commit_subject(commit_buffer, &subject);
 672                 strbuf_addf(buf, "%s %s %.*s\n", action_str, sha1_abbrev,
 673                         subject_len, subject);
 674                 unuse_commit_buffer(cur->item, commit_buffer);
 675         }
 676         return 0;
 677 }
 678
 679 static struct commit *parse_insn_line(char *bol, char *eol, struct replay_opts *opts)
 680 {
 681         unsigned char commit_sha1[20];
 682         enum replay_action action;
 683         char *end_of_object_name;
 684         int saved, status, padding;
 685
 686         if (starts_with(bol, "pick")) {
 687                 action = REPLAY_PICK;
 688                 bol += strlen("pick");
 689         } else if (starts_with(bol, "revert")) {
 690                 action = REPLAY_REVERT;
 691                 bol += strlen("revert");
 692         } else
 693                 return NULL;
 694
 695         /* Eat up extra spaces/ tabs before object name */
 696         padding = strspn(bol, " \t");
 697         if (!padding)
 698                 return NULL;
 699         bol += padding;
 700
 701         end_of_object_name = bol + strcspn(bol, " \t\n");
 702         saved = *end_of_object_name;
 703         *end_of_object_name = '\0';
 704         status = get_sha1(bol, commit_sha1);
 705         *end_of_object_name = saved;
 706
 707         /*
 708          * Verify that the action matches up with the one in
 709          * opts; we don't support arbitrary instructions
 710          */
 711         if (action != opts->action) {
 712                 const char *action_str;
 713                 action_str = action == REPLAY_REVERT ? "revert" : "cherry-pick";
 714                 error(_("Cannot %s during a %s"), action_str, action_name(opts));
 715                 return NULL;
 716         }
 717
 718         if (status < 0)
 719                 return NULL;
 720
 721         return lookup_commit_reference(commit_sha1);
 722 }
 723
 724 static int parse_insn_buffer(char *buf, struct commit_list **todo_list,
 725                         struct replay_opts *opts)
 726 {
 727         struct commit_list **next = todo_list;
 728         struct commit *commit;
 729         char *p = buf;
 730         int i;
 731
 732         for (i = 1; *p; i++) {
 733                 char *eol = strchrnul(p, '\n');
 734                 commit = parse_insn_line(p, eol, opts);
 735                 if (!commit)
 736                         return error(_("Could not parse line %d."), i);
 737                 next = commit_list_append(commit, next);
 738                 p = *eol ? eol + 1 : eol;
 739         }
 740         if (!*todo_list)
 741                 return error(_("No commits parsed."));
 742         return 0;
 743 }
 744
 745 static void read_populate_todo(struct commit_list **todo_list,
 746                         struct replay_opts *opts)
 747 {
 748         const char *todo_file = git_path(SEQ_TODO_FILE);
 749         struct strbuf buf = STRBUF_INIT;
 750         int fd, res;
 751
 752         fd = open(todo_file, O_RDONLY);
 753         if (fd < 0)
 754                 die_errno(_("Could not open %s"), todo_file);
 755         if (strbuf_read(&buf, fd, 0) < 0) {
 756                 close(fd);
 757                 strbuf_release(&buf);
 758                 die(_("Could not read %s."), todo_file);
 759         }
 760         close(fd);
 761
 762         res = parse_insn_buffer(buf.buf, todo_list, opts);
 763         strbuf_release(&buf);
 764         if (res)
 765                 die(_("Unusable instruction sheet: %s"), todo_file);
 766 }
 767
 768 static int populate_opts_cb(const char *key, const char *value, void *data)
 769 {
 770         struct replay_opts *opts = data;
 771         int error_flag = 1;
 772
 773         if (!value)
 774                 error_flag = 0;
 775         else if (!strcmp(key, "options.no-commit"))
 776                 opts->no_commit = git_config_bool_or_int(key, value, &error_flag);
 777         else if (!strcmp(key, "options.edit"))
 778                 opts->edit = git_config_bool_or_int(key, value, &error_flag);
 779         else if (!strcmp(key, "options.signoff"))
 780                 opts->signoff = git_config_bool_or_int(key, value, &error_flag);
 781         else if (!strcmp(key, "options.record-origin"))
 782                 opts->record_origin = git_config_bool_or_int(key, value, &error_flag);
 783         else if (!strcmp(key, "options.allow-ff"))
 784                 opts->allow_ff = git_config_bool_or_int(key, value, &error_flag);
 785         else if (!strcmp(key, "options.mainline"))
 786                 opts->mainline = git_config_int(key, value);
 787         else if (!strcmp(key, "options.strategy"))
 788                 git_config_string(&opts->strategy, key, value);
 789         else if (!strcmp(key, "options.gpg-sign"))
 790                 git_config_string(&opts->gpg_sign, key, value);
 791         else if (!strcmp(key, "options.strategy-option")) {
 792                 ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
 793                 opts->xopts[opts->xopts_nr++] = xstrdup(value);
 794         } else
 795                 return error(_("Invalid key: %s"), key);
 796
 797         if (!error_flag)
 798                 return error(_("Invalid value for %s: %s"), key, value);
 799
 800         return 0;
 801 }
 802
 803 static void read_populate_opts(struct replay_opts **opts_ptr)
 804 {
 805         const char *opts_file = git_path(SEQ_OPTS_FILE);
 806
 807         if (!file_exists(opts_file))
 808                 return;
 809         if (git_config_from_file(populate_opts_cb, opts_file, *opts_ptr) < 0)
 810                 die(_("Malformed options sheet: %s"), opts_file);
 811 }
 812
 813 static void walk_revs_populate_todo(struct commit_list **todo_list,
 814                                 struct replay_opts *opts)
 815 {
 816         struct commit *commit;
 817         struct commit_list **next;
 818
 819         prepare_revs(opts);
 820
 821         next = todo_list;
 822         while ((commit = get_revision(opts->revs)))
 823                 next = commit_list_append(commit, next);
 824 }
 825
 826 static int create_seq_dir(void)
 827 {
 828         const char *seq_dir = git_path(SEQ_DIR);
 829
 830         if (file_exists(seq_dir)) {
 831                 error(_("a cherry-pick or revert is already in progress"));
 832                 advise(_("try \"git cherry-pick (--continue | --quit | --abort)\""));
 833                 return -1;
 834         }
 835         else if (mkdir(seq_dir, 0777) < 0)
 836                 die_errno(_("Could not create sequencer directory %s"), seq_dir);
 837         return 0;
 838 }
 839
 840 static void save_head(const char *head)
 841 {
 842         const char *head_file = git_path(SEQ_HEAD_FILE);
 843         static struct lock_file head_lock;
 844         struct strbuf buf = STRBUF_INIT;
 845         int fd;
 846
 847         fd = hold_lock_file_for_update(&head_lock, head_file, LOCK_DIE_ON_ERROR);
 848         strbuf_addf(&buf, "%s\n", head);
 849         if (write_in_full(fd, buf.buf, buf.len) < 0)
 850                 die_errno(_("Could not write to %s"), head_file);
 851         if (commit_lock_file(&head_lock) < 0)
 852                 die(_("Error wrapping up %s."), head_file);
 853 }
 854
 855 static int reset_for_rollback(const unsigned char *sha1)
 856 {
 857         const char *argv[4];    /* reset --merge <arg> + NULL */
 858         argv[0] = "reset";
 859         argv[1] = "--merge";
 860         argv[2] = sha1_to_hex(sha1);
 861         argv[3] = NULL;
 862         return run_command_v_opt(argv, RUN_GIT_CMD);
 863 }
 864
 865 static int rollback_single_pick(void)
 866 {
 867         unsigned char head_sha1[20];
 868
 869         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
 870             !file_exists(git_path("REVERT_HEAD")))
 871                 return error(_("no cherry-pick or revert in progress"));
 872         if (read_ref_full("HEAD", head_sha1, 0, NULL))
 873                 return error(_("cannot resolve HEAD"));
 874         if (is_null_sha1(head_sha1))
 875                 return error(_("cannot abort from a branch yet to be born"));
 876         return reset_for_rollback(head_sha1);
 877 }
 878
 879 static int sequencer_rollback(struct replay_opts *opts)
 880 {
 881         const char *filename;
 882         FILE *f;
 883         unsigned char sha1[20];
 884         struct strbuf buf = STRBUF_INIT;
 885
 886         filename = git_path(SEQ_HEAD_FILE);
 887         f = fopen(filename, "r");
 888         if (!f && errno == ENOENT) {
 889                 /*
 890                  * There is no multiple-cherry-pick in progress.
 891                  * If CHERRY_PICK_HEAD or REVERT_HEAD indicates
 892                  * a single-cherry-pick in progress, abort that.
 893                  */
 894                 return rollback_single_pick();
 895         }
 896         if (!f)
 897                 return error(_("cannot open %s: %s"), filename,
 898                                                 strerror(errno));
 899         if (strbuf_getline(&buf, f, '\n')) {
 900                 error(_("cannot read %s: %s"), filename, ferror(f) ?
 901                         strerror(errno) : _("unexpected end of file"));
 902                 fclose(f);
 903                 goto fail;
 904         }
 905         fclose(f);
 906         if (get_sha1_hex(buf.buf, sha1) || buf.buf[40] != '\0') {
 907                 error(_("stored pre-cherry-pick HEAD file '%s' is corrupt"),
 908                         filename);
 909                 goto fail;
 910         }
 911         if (reset_for_rollback(sha1))
 912                 goto fail;
 913         remove_sequencer_state();
 914         strbuf_release(&buf);
 915         return 0;
 916 fail:
 917         strbuf_release(&buf);
 918         return -1;
 919 }
 920
 921 static void save_todo(struct commit_list *todo_list, struct replay_opts *opts)
 922 {
 923         const char *todo_file = git_path(SEQ_TODO_FILE);
 924         static struct lock_file todo_lock;
 925         struct strbuf buf = STRBUF_INIT;
 926         int fd;
 927
 928         fd = hold_lock_file_for_update(&todo_lock, todo_file, LOCK_DIE_ON_ERROR);
 929         if (format_todo(&buf, todo_list, opts) < 0)
 930                 die(_("Could not format %s."), todo_file);
 931         if (write_in_full(fd, buf.buf, buf.len) < 0) {
 932                 strbuf_release(&buf);
 933                 die_errno(_("Could not write to %s"), todo_file);
 934         }
 935         if (commit_lock_file(&todo_lock) < 0) {
 936                 strbuf_release(&buf);
 937                 die(_("Error wrapping up %s."), todo_file);
 938         }
 939         strbuf_release(&buf);
 940 }
 941
 942 static void save_opts(struct replay_opts *opts)
 943 {
 944         const char *opts_file = git_path(SEQ_OPTS_FILE);
 945
 946         if (opts->no_commit)
 947                 git_config_set_in_file(opts_file, "options.no-commit", "true");
 948         if (opts->edit)
 949                 git_config_set_in_file(opts_file, "options.edit", "true");
 950         if (opts->signoff)
 951                 git_config_set_in_file(opts_file, "options.signoff", "true");
 952         if (opts->record_origin)
 953                 git_config_set_in_file(opts_file, "options.record-origin", "true");
 954         if (opts->allow_ff)
 955                 git_config_set_in_file(opts_file, "options.allow-ff", "true");
 956         if (opts->mainline) {
 957                 struct strbuf buf = STRBUF_INIT;
 958                 strbuf_addf(&buf, "%d", opts->mainline);
 959                 git_config_set_in_file(opts_file, "options.mainline", buf.buf);
 960                 strbuf_release(&buf);
 961         }
 962         if (opts->strategy)
 963                 git_config_set_in_file(opts_file, "options.strategy", opts->strategy);
 964         if (opts->gpg_sign)
 965                 git_config_set_in_file(opts_file, "options.gpg-sign", opts->gpg_sign);
 966         if (opts->xopts) {
 967                 int i;
 968                 for (i = 0; i < opts->xopts_nr; i++)
 969                         git_config_set_multivar_in_file(opts_file,
 970                                                         "options.strategy-option",
 971                                                         opts->xopts[i], "^$", 0);
 972         }
 973 }
 974
 975 static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
 976 {
 977         struct commit_list *cur;
 978         int res;
 979
 980         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
 981         if (opts->allow_ff)
 982                 assert(!(opts->signoff || opts->no_commit ||
 983                                 opts->record_origin || opts->edit));
 984         read_and_refresh_cache(opts);
 985
 986         for (cur = todo_list; cur; cur = cur->next) {
 987                 save_todo(cur, opts);
 988                 res = do_pick_commit(cur->item, opts);
 989                 if (res)
 990                         return res;
 991         }
 992
 993         /*
 994          * Sequence of picks finished successfully; cleanup by
 995          * removing the .git/sequencer directory
 996          */
 997         remove_sequencer_state();
 998         return 0;
 999 }
1000
1001 static int continue_single_pick(void)
1002 {
1003         const char *argv[] = { "commit", NULL };
1004
1005         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
1006             !file_exists(git_path("REVERT_HEAD")))
1007                 return error(_("no cherry-pick or revert in progress"));
1008         return run_command_v_opt(argv, RUN_GIT_CMD);
1009 }
1010
1011 static int sequencer_continue(struct replay_opts *opts)
1012 {
1013         struct commit_list *todo_list = NULL;
1014
1015         if (!file_exists(git_path(SEQ_TODO_FILE)))
1016                 return continue_single_pick();
1017         read_populate_opts(&opts);
1018         read_populate_todo(&todo_list, opts);
1019
1020         /* Verify that the conflict has been resolved */
1021         if (file_exists(git_path("CHERRY_PICK_HEAD")) ||
1022             file_exists(git_path("REVERT_HEAD"))) {
1023                 int ret = continue_single_pick();
1024                 if (ret)
1025                         return ret;
1026         }
1027         if (index_differs_from("HEAD", 0))
1028                 return error_dirty_index(opts);
1029         todo_list = todo_list->next;
1030         return pick_commits(todo_list, opts);
1031 }
1032
1033 static int single_pick(struct commit *cmit, struct replay_opts *opts)
1034 {
1035         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
1036         return do_pick_commit(cmit, opts);
1037 }
1038
1039 int sequencer_pick_revisions(struct replay_opts *opts)
1040 {
1041         struct commit_list *todo_list = NULL;
1042         unsigned char sha1[20];
1043         int i;
1044
1045         if (opts->subcommand == REPLAY_NONE)
1046                 assert(opts->revs);
1047
1048         read_and_refresh_cache(opts);
1049
1050         /*
1051          * Decide what to do depending on the arguments; a fresh
1052          * cherry-pick should be handled differently from an existing
1053          * one that is being continued
1054          */
1055         if (opts->subcommand == REPLAY_REMOVE_STATE) {
1056                 remove_sequencer_state();
1057                 return 0;
1058         }
1059         if (opts->subcommand == REPLAY_ROLLBACK)
1060                 return sequencer_rollback(opts);
1061         if (opts->subcommand == REPLAY_CONTINUE)
1062                 return sequencer_continue(opts);
1063
1064         for (i = 0; i < opts->revs->pending.nr; i++) {
1065                 unsigned char sha1[20];
1066                 const char *name = opts->revs->pending.objects[i].name;
1067
1068                 /* This happens when using --stdin. */
1069                 if (!strlen(name))
1070                         continue;
1071
1072                 if (!get_sha1(name, sha1)) {
1073                         if (!lookup_commit_reference_gently(sha1, 1)) {
1074                                 enum object_type type = sha1_object_info(sha1, NULL);
1075                                 die(_("%s: can't cherry-pick a %s"), name, typename(type));
1076                         }
1077                 } else
1078                         die(_("%s: bad revision"), name);
1079         }
1080
1081         /*
1082          * If we were called as "git cherry-pick <commit>", just
1083          * cherry-pick/revert it, set CHERRY_PICK_HEAD /
1084          * REVERT_HEAD, and don't touch the sequencer state.
1085          * This means it is possible to cherry-pick in the middle
1086          * of a cherry-pick sequence.
1087          */
1088         if (opts->revs->cmdline.nr == 1 &&
1089             opts->revs->cmdline.rev->whence == REV_CMD_REV &&
1090             opts->revs->no_walk &&
1091             !opts->revs->cmdline.rev->flags) {
1092                 struct commit *cmit;
1093                 if (prepare_revision_walk(opts->revs))
1094                         die(_("revision walk setup failed"));
1095                 cmit = get_revision(opts->revs);
1096                 if (!cmit || get_revision(opts->revs))
1097                         die("BUG: expected exactly one commit from walk");
1098                 return single_pick(cmit, opts);
1099         }
1100
1101         /*
1102          * Start a new cherry-pick/ revert sequence; but
1103          * first, make sure that an existing one isn't in
1104          * progress
1105          */
1106
1107         walk_revs_populate_todo(&todo_list, opts);
1108         if (create_seq_dir() < 0)
1109                 return -1;
1110         if (get_sha1("HEAD", sha1)) {
1111                 if (opts->action == REPLAY_REVERT)
1112                         return error(_("Can't revert as initial commit"));
1113                 return error(_("Can't cherry-pick into empty head"));
1114         }
1115         save_head(sha1_to_hex(sha1));
1116         save_opts(opts);
1117         return pick_commits(todo_list, opts);
1118 }
1119
1120 void append_signoff(struct strbuf *msgbuf, int ignore_footer, unsigned flag)
1121 {
1122         unsigned no_dup_sob = flag & APPEND_SIGNOFF_DEDUP;
1123         struct strbuf sob = STRBUF_INIT;
1124         int has_footer;
1125
1126         strbuf_addstr(&sob, sign_off_header);
1127         strbuf_addstr(&sob, fmt_name(getenv("GIT_COMMITTER_NAME"),
1128                                 getenv("GIT_COMMITTER_EMAIL")));
1129         strbuf_addch(&sob, '\n');
1130
1131         /*
1132          * If the whole message buffer is equal to the sob, pretend that we
1133          * found a conforming footer with a matching sob
1134          */
1135         if (msgbuf->len - ignore_footer == sob.len &&
1136             !strncmp(msgbuf->buf, sob.buf, sob.len))
1137                 has_footer = 3;
1138         else
1139                 has_footer = has_conforming_footer(msgbuf, &sob, ignore_footer);
1140
1141         if (!has_footer) {
1142                 const char *append_newlines = NULL;
1143                 size_t len = msgbuf->len - ignore_footer;
1144
1145                 if (!len) {
1146                         /*
1147                          * The buffer is completely empty.  Leave foom for
1148                          * the title and body to be filled in by the user.
1149                          */
1150                         append_newlines = "\n\n";
1151                 } else if (msgbuf->buf[len - 1] != '\n') {
1152                         /*
1153                          * Incomplete line.  Complete the line and add a
1154                          * blank one so that there is an empty line between
1155                          * the message body and the sob.
1156                          */
1157                         append_newlines = "\n\n";
1158                 } else if (len == 1) {
1159                         /*
1160                          * Buffer contains a single newline.  Add another
1161                          * so that we leave room for the title and body.
1162                          */
1163                         append_newlines = "\n";
1164                 } else if (msgbuf->buf[len - 2] != '\n') {
1165                         /*
1166                          * Buffer ends with a single newline.  Add another
1167                          * so that there is an empty line between the message
1168                          * body and the sob.
1169                          */
1170                         append_newlines = "\n";
1171                 } /* else, the buffer already ends with two newlines. */
1172
1173                 if (append_newlines)
1174                         strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0,
1175                                 append_newlines, strlen(append_newlines));
1176         }
1177
1178         if (has_footer != 3 && (!no_dup_sob || has_footer != 2))
1179                 strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0,
1180                                 sob.buf, sob.len);
1181
1182         strbuf_release(&sob);
1183 }