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
  22 static void remove_sequencer_state(void)
  23 {
  24         struct strbuf seq_dir = STRBUF_INIT;
  25
  26         strbuf_addf(&seq_dir, "%s", git_path(SEQ_DIR));
  27         remove_dir_recursively(&seq_dir, 0);
  28         strbuf_release(&seq_dir);
  29 }
  30
  31 static const char *action_name(const struct replay_opts *opts)
  32 {
  33         return opts->action == REPLAY_REVERT ? "revert" : "cherry-pick";
  34 }
  35
  36 static char *get_encoding(const char *message);
  37
  38 struct commit_message {
  39         char *parent_label;
  40         const char *label;
  41         const char *subject;
  42         char *reencoded_message;
  43         const char *message;
  44 };
  45
  46 static int get_message(struct commit *commit, struct commit_message *out)
  47 {
  48         const char *encoding;
  49         const char *abbrev, *subject;
  50         int abbrev_len, subject_len;
  51         char *q;
  52
  53         if (!commit->buffer)
  54                 return -1;
  55         encoding = get_encoding(commit->buffer);
  56         if (!encoding)
  57                 encoding = "UTF-8";
  58         if (!git_commit_encoding)
  59                 git_commit_encoding = "UTF-8";
  60
  61         out->reencoded_message = NULL;
  62         out->message = commit->buffer;
  63         if (same_encoding(encoding, git_commit_encoding))
  64                 out->reencoded_message = reencode_string(commit->buffer,
  65                                         git_commit_encoding, encoding);
  66         if (out->reencoded_message)
  67                 out->message = out->reencoded_message;
  68
  69         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
  70         abbrev_len = strlen(abbrev);
  71
  72         subject_len = find_commit_subject(out->message, &subject);
  73
  74         out->parent_label = xmalloc(strlen("parent of ") + abbrev_len +
  75                               strlen("... ") + subject_len + 1);
  76         q = out->parent_label;
  77         q = mempcpy(q, "parent of ", strlen("parent of "));
  78         out->label = q;
  79         q = mempcpy(q, abbrev, abbrev_len);
  80         q = mempcpy(q, "... ", strlen("... "));
  81         out->subject = q;
  82         q = mempcpy(q, subject, subject_len);
  83         *q = '\0';
  84         return 0;
  85 }
  86
  87 static void free_message(struct commit_message *msg)
  88 {
  89         free(msg->parent_label);
  90         free(msg->reencoded_message);
  91 }
  92
  93 static char *get_encoding(const char *message)
  94 {
  95         const char *p = message, *eol;
  96
  97         while (*p && *p != '\n') {
  98                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
  99                         ; /* do nothing */
 100                 if (!prefixcmp(p, "encoding ")) {
 101                         char *result = xmalloc(eol - 8 - p);
 102                         strlcpy(result, p + 9, eol - 8 - p);
 103                         return result;
 104                 }
 105                 p = eol;
 106                 if (*p == '\n')
 107                         p++;
 108         }
 109         return NULL;
 110 }
 111
 112 static void write_cherry_pick_head(struct commit *commit, const char *pseudoref)
 113 {
 114         const char *filename;
 115         int fd;
 116         struct strbuf buf = STRBUF_INIT;
 117
 118         strbuf_addf(&buf, "%s\n", sha1_to_hex(commit->object.sha1));
 119
 120         filename = git_path("%s", pseudoref);
 121         fd = open(filename, O_WRONLY | O_CREAT, 0666);
 122         if (fd < 0)
 123                 die_errno(_("Could not open '%s' for writing"), filename);
 124         if (write_in_full(fd, buf.buf, buf.len) != buf.len || close(fd))
 125                 die_errno(_("Could not write to '%s'"), filename);
 126         strbuf_release(&buf);
 127 }
 128
 129 static void print_advice(int show_hint, struct replay_opts *opts)
 130 {
 131         char *msg = getenv("GIT_CHERRY_PICK_HELP");
 132
 133         if (msg) {
 134                 fprintf(stderr, "%s\n", msg);
 135                 /*
 136                  * A conflict has occured but the porcelain
 137                  * (typically rebase --interactive) wants to take care
 138                  * of the commit itself so remove CHERRY_PICK_HEAD
 139                  */
 140                 unlink(git_path("CHERRY_PICK_HEAD"));
 141                 return;
 142         }
 143
 144         if (show_hint) {
 145                 if (opts->no_commit)
 146                         advise(_("after resolving the conflicts, mark the corrected paths\n"
 147                                  "with 'git add <paths>' or 'git rm <paths>'"));
 148                 else
 149                         advise(_("after resolving the conflicts, mark the corrected paths\n"
 150                                  "with 'git add <paths>' or 'git rm <paths>'\n"
 151                                  "and commit the result with 'git commit'"));
 152         }
 153 }
 154
 155 static void write_message(struct strbuf *msgbuf, const char *filename)
 156 {
 157         static struct lock_file msg_file;
 158
 159         int msg_fd = hold_lock_file_for_update(&msg_file, filename,
 160                                                LOCK_DIE_ON_ERROR);
 161         if (write_in_full(msg_fd, msgbuf->buf, msgbuf->len) < 0)
 162                 die_errno(_("Could not write to %s"), filename);
 163         strbuf_release(msgbuf);
 164         if (commit_lock_file(&msg_file) < 0)
 165                 die(_("Error wrapping up %s"), filename);
 166 }
 167
 168 static struct tree *empty_tree(void)
 169 {
 170         return lookup_tree(EMPTY_TREE_SHA1_BIN);
 171 }
 172
 173 static int error_dirty_index(struct replay_opts *opts)
 174 {
 175         if (read_cache_unmerged())
 176                 return error_resolve_conflict(action_name(opts));
 177
 178         /* Different translation strings for cherry-pick and revert */
 179         if (opts->action == REPLAY_PICK)
 180                 error(_("Your local changes would be overwritten by cherry-pick."));
 181         else
 182                 error(_("Your local changes would be overwritten by revert."));
 183
 184         if (advice_commit_before_merge)
 185                 advise(_("Commit your changes or stash them to proceed."));
 186         return -1;
 187 }
 188
 189 static int fast_forward_to(const unsigned char *to, const unsigned char *from)
 190 {
 191         struct ref_lock *ref_lock;
 192
 193         read_cache();
 194         if (checkout_fast_forward(from, to, 1))
 195                 exit(1); /* the callee should have complained already */
 196         ref_lock = lock_any_ref_for_update("HEAD", from, 0);
 197         return write_ref_sha1(ref_lock, to, "cherry-pick");
 198 }
 199
 200 static int do_recursive_merge(struct commit *base, struct commit *next,
 201                               const char *base_label, const char *next_label,
 202                               unsigned char *head, struct strbuf *msgbuf,
 203                               struct replay_opts *opts)
 204 {
 205         struct merge_options o;
 206         struct tree *result, *next_tree, *base_tree, *head_tree;
 207         int clean, index_fd;
 208         const char **xopt;
 209         static struct lock_file index_lock;
 210
 211         index_fd = hold_locked_index(&index_lock, 1);
 212
 213         read_cache();
 214
 215         init_merge_options(&o);
 216         o.ancestor = base ? base_label : "(empty tree)";
 217         o.branch1 = "HEAD";
 218         o.branch2 = next ? next_label : "(empty tree)";
 219
 220         head_tree = parse_tree_indirect(head);
 221         next_tree = next ? next->tree : empty_tree();
 222         base_tree = base ? base->tree : empty_tree();
 223
 224         for (xopt = opts->xopts; xopt != opts->xopts + opts->xopts_nr; xopt++)
 225                 parse_merge_opt(&o, *xopt);
 226
 227         clean = merge_trees(&o,
 228                             head_tree,
 229                             next_tree, base_tree, &result);
 230
 231         if (active_cache_changed &&
 232             (write_cache(index_fd, active_cache, active_nr) ||
 233              commit_locked_index(&index_lock)))
 234                 /* TRANSLATORS: %s will be "revert" or "cherry-pick" */
 235                 die(_("%s: Unable to write new index file"), action_name(opts));
 236         rollback_lock_file(&index_lock);
 237
 238         if (opts->signoff)
 239                 append_signoff(msgbuf, 0);
 240
 241         if (!clean) {
 242                 int i;
 243                 strbuf_addstr(msgbuf, "\nConflicts:\n");
 244                 for (i = 0; i < active_nr;) {
 245                         struct cache_entry *ce = active_cache[i++];
 246                         if (ce_stage(ce)) {
 247                                 strbuf_addch(msgbuf, '\t');
 248                                 strbuf_addstr(msgbuf, ce->name);
 249                                 strbuf_addch(msgbuf, '\n');
 250                                 while (i < active_nr && !strcmp(ce->name,
 251                                                 active_cache[i]->name))
 252                                         i++;
 253                         }
 254                 }
 255         }
 256
 257         return !clean;
 258 }
 259
 260 static int is_index_unchanged(void)
 261 {
 262         unsigned char head_sha1[20];
 263         struct commit *head_commit;
 264
 265         if (!resolve_ref_unsafe("HEAD", head_sha1, 1, NULL))
 266                 return error(_("Could not resolve HEAD commit\n"));
 267
 268         head_commit = lookup_commit(head_sha1);
 269
 270         /*
 271          * If head_commit is NULL, check_commit, called from
 272          * lookup_commit, would have indicated that head_commit is not
 273          * a commit object already.  parse_commit() will return failure
 274          * without further complaints in such a case.  Otherwise, if
 275          * the commit is invalid, parse_commit() will complain.  So
 276          * there is nothing for us to say here.  Just return failure.
 277          */
 278         if (parse_commit(head_commit))
 279                 return -1;
 280
 281         if (!active_cache_tree)
 282                 active_cache_tree = cache_tree();
 283
 284         if (!cache_tree_fully_valid(active_cache_tree))
 285                 if (cache_tree_update(active_cache_tree, active_cache,
 286                                   active_nr, 0))
 287                         return error(_("Unable to update cache tree\n"));
 288
 289         return !hashcmp(active_cache_tree->sha1, head_commit->tree->object.sha1);
 290 }
 291
 292 /*
 293  * If we are cherry-pick, and if the merge did not result in
 294  * hand-editing, we will hit this commit and inherit the original
 295  * author date and name.
 296  * If we are revert, or if our cherry-pick results in a hand merge,
 297  * we had better say that the current user is responsible for that.
 298  */
 299 static int run_git_commit(const char *defmsg, struct replay_opts *opts,
 300                           int allow_empty)
 301 {
 302         struct argv_array array;
 303         int rc;
 304
 305         argv_array_init(&array);
 306         argv_array_push(&array, "commit");
 307         argv_array_push(&array, "-n");
 308
 309         if (opts->signoff)
 310                 argv_array_push(&array, "-s");
 311         if (!opts->edit) {
 312                 argv_array_push(&array, "-F");
 313                 argv_array_push(&array, defmsg);
 314         }
 315
 316         if (allow_empty)
 317                 argv_array_push(&array, "--allow-empty");
 318
 319         if (opts->allow_empty_message)
 320                 argv_array_push(&array, "--allow-empty-message");
 321
 322         rc = run_command_v_opt(array.argv, RUN_GIT_CMD);
 323         argv_array_clear(&array);
 324         return rc;
 325 }
 326
 327 static int is_original_commit_empty(struct commit *commit)
 328 {
 329         const unsigned char *ptree_sha1;
 330
 331         if (parse_commit(commit))
 332                 return error(_("Could not parse commit %s\n"),
 333                              sha1_to_hex(commit->object.sha1));
 334         if (commit->parents) {
 335                 struct commit *parent = commit->parents->item;
 336                 if (parse_commit(parent))
 337                         return error(_("Could not parse parent commit %s\n"),
 338                                 sha1_to_hex(parent->object.sha1));
 339                 ptree_sha1 = parent->tree->object.sha1;
 340         } else {
 341                 ptree_sha1 = EMPTY_TREE_SHA1_BIN; /* commit is root */
 342         }
 343
 344         return !hashcmp(ptree_sha1, commit->tree->object.sha1);
 345 }
 346
 347 /*
 348  * Do we run "git commit" with "--allow-empty"?
 349  */
 350 static int allow_empty(struct replay_opts *opts, struct commit *commit)
 351 {
 352         int index_unchanged, empty_commit;
 353
 354         /*
 355          * Three cases:
 356          *
 357          * (1) we do not allow empty at all and error out.
 358          *
 359          * (2) we allow ones that were initially empty, but
 360          * forbid the ones that become empty;
 361          *
 362          * (3) we allow both.
 363          */
 364         if (!opts->allow_empty)
 365                 return 0; /* let "git commit" barf as necessary */
 366
 367         index_unchanged = is_index_unchanged();
 368         if (index_unchanged < 0)
 369                 return index_unchanged;
 370         if (!index_unchanged)
 371                 return 0; /* we do not have to say --allow-empty */
 372
 373         if (opts->keep_redundant_commits)
 374                 return 1;
 375
 376         empty_commit = is_original_commit_empty(commit);
 377         if (empty_commit < 0)
 378                 return empty_commit;
 379         if (!empty_commit)
 380                 return 0;
 381         else
 382                 return 1;
 383 }
 384
 385 static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
 386 {
 387         unsigned char head[20];
 388         struct commit *base, *next, *parent;
 389         const char *base_label, *next_label;
 390         struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
 391         char *defmsg = NULL;
 392         struct strbuf msgbuf = STRBUF_INIT;
 393         int res;
 394
 395         if (opts->no_commit) {
 396                 /*
 397                  * We do not intend to commit immediately.  We just want to
 398                  * merge the differences in, so let's compute the tree
 399                  * that represents the "current" state for merge-recursive
 400                  * to work on.
 401                  */
 402                 if (write_cache_as_tree(head, 0, NULL))
 403                         die (_("Your index file is unmerged."));
 404         } else {
 405                 if (get_sha1("HEAD", head))
 406                         return error(_("You do not have a valid HEAD"));
 407                 if (index_differs_from("HEAD", 0))
 408                         return error_dirty_index(opts);
 409         }
 410         discard_cache();
 411
 412         if (!commit->parents) {
 413                 parent = NULL;
 414         }
 415         else if (commit->parents->next) {
 416                 /* Reverting or cherry-picking a merge commit */
 417                 int cnt;
 418                 struct commit_list *p;
 419
 420                 if (!opts->mainline)
 421                         return error(_("Commit %s is a merge but no -m option was given."),
 422                                 sha1_to_hex(commit->object.sha1));
 423
 424                 for (cnt = 1, p = commit->parents;
 425                      cnt != opts->mainline && p;
 426                      cnt++)
 427                         p = p->next;
 428                 if (cnt != opts->mainline || !p)
 429                         return error(_("Commit %s does not have parent %d"),
 430                                 sha1_to_hex(commit->object.sha1), opts->mainline);
 431                 parent = p->item;
 432         } else if (0 < opts->mainline)
 433                 return error(_("Mainline was specified but commit %s is not a merge."),
 434                         sha1_to_hex(commit->object.sha1));
 435         else
 436                 parent = commit->parents->item;
 437
 438         if (opts->allow_ff && parent && !hashcmp(parent->object.sha1, head))
 439                 return fast_forward_to(commit->object.sha1, head);
 440
 441         if (parent && parse_commit(parent) < 0)
 442                 /* TRANSLATORS: The first %s will be "revert" or
 443                    "cherry-pick", the second %s a SHA1 */
 444                 return error(_("%s: cannot parse parent commit %s"),
 445                         action_name(opts), sha1_to_hex(parent->object.sha1));
 446
 447         if (get_message(commit, &msg) != 0)
 448                 return error(_("Cannot get commit message for %s"),
 449                         sha1_to_hex(commit->object.sha1));
 450
 451         /*
 452          * "commit" is an existing commit.  We would want to apply
 453          * the difference it introduces since its first parent "prev"
 454          * on top of the current HEAD if we are cherry-pick.  Or the
 455          * reverse of it if we are revert.
 456          */
 457
 458         defmsg = git_pathdup("MERGE_MSG");
 459
 460         if (opts->action == REPLAY_REVERT) {
 461                 base = commit;
 462                 base_label = msg.label;
 463                 next = parent;
 464                 next_label = msg.parent_label;
 465                 strbuf_addstr(&msgbuf, "Revert \"");
 466                 strbuf_addstr(&msgbuf, msg.subject);
 467                 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
 468                 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 469
 470                 if (commit->parents && commit->parents->next) {
 471                         strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
 472                         strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
 473                 }
 474                 strbuf_addstr(&msgbuf, ".\n");
 475         } else {
 476                 const char *p;
 477
 478                 base = parent;
 479                 base_label = msg.parent_label;
 480                 next = commit;
 481                 next_label = msg.label;
 482
 483                 /*
 484                  * Append the commit log message to msgbuf; it starts
 485                  * after the tree, parent, author, committer
 486                  * information followed by "\n\n".
 487                  */
 488                 p = strstr(msg.message, "\n\n");
 489                 if (p) {
 490                         p += 2;
 491                         strbuf_addstr(&msgbuf, p);
 492                 }
 493
 494                 if (opts->record_origin) {
 495                         strbuf_addstr(&msgbuf, "(cherry picked from commit ");
 496                         strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 497                         strbuf_addstr(&msgbuf, ")\n");
 498                 }
 499         }
 500
 501         if (!opts->strategy || !strcmp(opts->strategy, "recursive") || opts->action == REPLAY_REVERT) {
 502                 res = do_recursive_merge(base, next, base_label, next_label,
 503                                          head, &msgbuf, opts);
 504                 write_message(&msgbuf, defmsg);
 505         } else {
 506                 struct commit_list *common = NULL;
 507                 struct commit_list *remotes = NULL;
 508
 509                 write_message(&msgbuf, defmsg);
 510
 511                 commit_list_insert(base, &common);
 512                 commit_list_insert(next, &remotes);
 513                 res = try_merge_command(opts->strategy, opts->xopts_nr, opts->xopts,
 514                                         common, sha1_to_hex(head), remotes);
 515                 free_commit_list(common);
 516                 free_commit_list(remotes);
 517         }
 518
 519         /*
 520          * If the merge was clean or if it failed due to conflict, we write
 521          * CHERRY_PICK_HEAD for the subsequent invocation of commit to use.
 522          * However, if the merge did not even start, then we don't want to
 523          * write it at all.
 524          */
 525         if (opts->action == REPLAY_PICK && !opts->no_commit && (res == 0 || res == 1))
 526                 write_cherry_pick_head(commit, "CHERRY_PICK_HEAD");
 527         if (opts->action == REPLAY_REVERT && ((opts->no_commit && res == 0) || res == 1))
 528                 write_cherry_pick_head(commit, "REVERT_HEAD");
 529
 530         if (res) {
 531                 error(opts->action == REPLAY_REVERT
 532                       ? _("could not revert %s... %s")
 533                       : _("could not apply %s... %s"),
 534                       find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV),
 535                       msg.subject);
 536                 print_advice(res == 1, opts);
 537                 rerere(opts->allow_rerere_auto);
 538         } else {
 539                 int allow = allow_empty(opts, commit);
 540                 if (allow < 0)
 541                         return allow;
 542                 if (!opts->no_commit)
 543                         res = run_git_commit(defmsg, opts, allow);
 544         }
 545
 546         free_message(&msg);
 547         free(defmsg);
 548
 549         return res;
 550 }
 551
 552 static void prepare_revs(struct replay_opts *opts)
 553 {
 554         /*
 555          * picking (but not reverting) ranges (but not individual revisions)
 556          * should be done in reverse
 557          */
 558         if (opts->action == REPLAY_PICK && !opts->revs->no_walk)
 559                 opts->revs->reverse ^= 1;
 560
 561         if (prepare_revision_walk(opts->revs))
 562                 die(_("revision walk setup failed"));
 563
 564         if (!opts->revs->commits)
 565                 die(_("empty commit set passed"));
 566 }
 567
 568 static void read_and_refresh_cache(struct replay_opts *opts)
 569 {
 570         static struct lock_file index_lock;
 571         int index_fd = hold_locked_index(&index_lock, 0);
 572         if (read_index_preload(&the_index, NULL) < 0)
 573                 die(_("git %s: failed to read the index"), action_name(opts));
 574         refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
 575         if (the_index.cache_changed) {
 576                 if (write_index(&the_index, index_fd) ||
 577                     commit_locked_index(&index_lock))
 578                         die(_("git %s: failed to refresh the index"), action_name(opts));
 579         }
 580         rollback_lock_file(&index_lock);
 581 }
 582
 583 static int format_todo(struct strbuf *buf, struct commit_list *todo_list,
 584                 struct replay_opts *opts)
 585 {
 586         struct commit_list *cur = NULL;
 587         const char *sha1_abbrev = NULL;
 588         const char *action_str = opts->action == REPLAY_REVERT ? "revert" : "pick";
 589         const char *subject;
 590         int subject_len;
 591
 592         for (cur = todo_list; cur; cur = cur->next) {
 593                 sha1_abbrev = find_unique_abbrev(cur->item->object.sha1, DEFAULT_ABBREV);
 594                 subject_len = find_commit_subject(cur->item->buffer, &subject);
 595                 strbuf_addf(buf, "%s %s %.*s\n", action_str, sha1_abbrev,
 596                         subject_len, subject);
 597         }
 598         return 0;
 599 }
 600
 601 static struct commit *parse_insn_line(char *bol, char *eol, struct replay_opts *opts)
 602 {
 603         unsigned char commit_sha1[20];
 604         enum replay_action action;
 605         char *end_of_object_name;
 606         int saved, status, padding;
 607
 608         if (!prefixcmp(bol, "pick")) {
 609                 action = REPLAY_PICK;
 610                 bol += strlen("pick");
 611         } else if (!prefixcmp(bol, "revert")) {
 612                 action = REPLAY_REVERT;
 613                 bol += strlen("revert");
 614         } else
 615                 return NULL;
 616
 617         /* Eat up extra spaces/ tabs before object name */
 618         padding = strspn(bol, " \t");
 619         if (!padding)
 620                 return NULL;
 621         bol += padding;
 622
 623         end_of_object_name = bol + strcspn(bol, " \t\n");
 624         saved = *end_of_object_name;
 625         *end_of_object_name = '\0';
 626         status = get_sha1(bol, commit_sha1);
 627         *end_of_object_name = saved;
 628
 629         /*
 630          * Verify that the action matches up with the one in
 631          * opts; we don't support arbitrary instructions
 632          */
 633         if (action != opts->action) {
 634                 const char *action_str;
 635                 action_str = action == REPLAY_REVERT ? "revert" : "cherry-pick";
 636                 error(_("Cannot %s during a %s"), action_str, action_name(opts));
 637                 return NULL;
 638         }
 639
 640         if (status < 0)
 641                 return NULL;
 642
 643         return lookup_commit_reference(commit_sha1);
 644 }
 645
 646 static int parse_insn_buffer(char *buf, struct commit_list **todo_list,
 647                         struct replay_opts *opts)
 648 {
 649         struct commit_list **next = todo_list;
 650         struct commit *commit;
 651         char *p = buf;
 652         int i;
 653
 654         for (i = 1; *p; i++) {
 655                 char *eol = strchrnul(p, '\n');
 656                 commit = parse_insn_line(p, eol, opts);
 657                 if (!commit)
 658                         return error(_("Could not parse line %d."), i);
 659                 next = commit_list_append(commit, next);
 660                 p = *eol ? eol + 1 : eol;
 661         }
 662         if (!*todo_list)
 663                 return error(_("No commits parsed."));
 664         return 0;
 665 }
 666
 667 static void read_populate_todo(struct commit_list **todo_list,
 668                         struct replay_opts *opts)
 669 {
 670         const char *todo_file = git_path(SEQ_TODO_FILE);
 671         struct strbuf buf = STRBUF_INIT;
 672         int fd, res;
 673
 674         fd = open(todo_file, O_RDONLY);
 675         if (fd < 0)
 676                 die_errno(_("Could not open %s"), todo_file);
 677         if (strbuf_read(&buf, fd, 0) < 0) {
 678                 close(fd);
 679                 strbuf_release(&buf);
 680                 die(_("Could not read %s."), todo_file);
 681         }
 682         close(fd);
 683
 684         res = parse_insn_buffer(buf.buf, todo_list, opts);
 685         strbuf_release(&buf);
 686         if (res)
 687                 die(_("Unusable instruction sheet: %s"), todo_file);
 688 }
 689
 690 static int populate_opts_cb(const char *key, const char *value, void *data)
 691 {
 692         struct replay_opts *opts = data;
 693         int error_flag = 1;
 694
 695         if (!value)
 696                 error_flag = 0;
 697         else if (!strcmp(key, "options.no-commit"))
 698                 opts->no_commit = git_config_bool_or_int(key, value, &error_flag);
 699         else if (!strcmp(key, "options.edit"))
 700                 opts->edit = git_config_bool_or_int(key, value, &error_flag);
 701         else if (!strcmp(key, "options.signoff"))
 702                 opts->signoff = git_config_bool_or_int(key, value, &error_flag);
 703         else if (!strcmp(key, "options.record-origin"))
 704                 opts->record_origin = git_config_bool_or_int(key, value, &error_flag);
 705         else if (!strcmp(key, "options.allow-ff"))
 706                 opts->allow_ff = git_config_bool_or_int(key, value, &error_flag);
 707         else if (!strcmp(key, "options.mainline"))
 708                 opts->mainline = git_config_int(key, value);
 709         else if (!strcmp(key, "options.strategy"))
 710                 git_config_string(&opts->strategy, key, value);
 711         else if (!strcmp(key, "options.strategy-option")) {
 712                 ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
 713                 opts->xopts[opts->xopts_nr++] = xstrdup(value);
 714         } else
 715                 return error(_("Invalid key: %s"), key);
 716
 717         if (!error_flag)
 718                 return error(_("Invalid value for %s: %s"), key, value);
 719
 720         return 0;
 721 }
 722
 723 static void read_populate_opts(struct replay_opts **opts_ptr)
 724 {
 725         const char *opts_file = git_path(SEQ_OPTS_FILE);
 726
 727         if (!file_exists(opts_file))
 728                 return;
 729         if (git_config_from_file(populate_opts_cb, opts_file, *opts_ptr) < 0)
 730                 die(_("Malformed options sheet: %s"), opts_file);
 731 }
 732
 733 static void walk_revs_populate_todo(struct commit_list **todo_list,
 734                                 struct replay_opts *opts)
 735 {
 736         struct commit *commit;
 737         struct commit_list **next;
 738
 739         prepare_revs(opts);
 740
 741         next = todo_list;
 742         while ((commit = get_revision(opts->revs)))
 743                 next = commit_list_append(commit, next);
 744 }
 745
 746 static int create_seq_dir(void)
 747 {
 748         const char *seq_dir = git_path(SEQ_DIR);
 749
 750         if (file_exists(seq_dir)) {
 751                 error(_("a cherry-pick or revert is already in progress"));
 752                 advise(_("try \"git cherry-pick (--continue | --quit | --abort)\""));
 753                 return -1;
 754         }
 755         else if (mkdir(seq_dir, 0777) < 0)
 756                 die_errno(_("Could not create sequencer directory %s"), seq_dir);
 757         return 0;
 758 }
 759
 760 static void save_head(const char *head)
 761 {
 762         const char *head_file = git_path(SEQ_HEAD_FILE);
 763         static struct lock_file head_lock;
 764         struct strbuf buf = STRBUF_INIT;
 765         int fd;
 766
 767         fd = hold_lock_file_for_update(&head_lock, head_file, LOCK_DIE_ON_ERROR);
 768         strbuf_addf(&buf, "%s\n", head);
 769         if (write_in_full(fd, buf.buf, buf.len) < 0)
 770                 die_errno(_("Could not write to %s"), head_file);
 771         if (commit_lock_file(&head_lock) < 0)
 772                 die(_("Error wrapping up %s."), head_file);
 773 }
 774
 775 static int reset_for_rollback(const unsigned char *sha1)
 776 {
 777         const char *argv[4];    /* reset --merge <arg> + NULL */
 778         argv[0] = "reset";
 779         argv[1] = "--merge";
 780         argv[2] = sha1_to_hex(sha1);
 781         argv[3] = NULL;
 782         return run_command_v_opt(argv, RUN_GIT_CMD);
 783 }
 784
 785 static int rollback_single_pick(void)
 786 {
 787         unsigned char head_sha1[20];
 788
 789         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
 790             !file_exists(git_path("REVERT_HEAD")))
 791                 return error(_("no cherry-pick or revert in progress"));
 792         if (read_ref_full("HEAD", head_sha1, 0, NULL))
 793                 return error(_("cannot resolve HEAD"));
 794         if (is_null_sha1(head_sha1))
 795                 return error(_("cannot abort from a branch yet to be born"));
 796         return reset_for_rollback(head_sha1);
 797 }
 798
 799 static int sequencer_rollback(struct replay_opts *opts)
 800 {
 801         const char *filename;
 802         FILE *f;
 803         unsigned char sha1[20];
 804         struct strbuf buf = STRBUF_INIT;
 805
 806         filename = git_path(SEQ_HEAD_FILE);
 807         f = fopen(filename, "r");
 808         if (!f && errno == ENOENT) {
 809                 /*
 810                  * There is no multiple-cherry-pick in progress.
 811                  * If CHERRY_PICK_HEAD or REVERT_HEAD indicates
 812                  * a single-cherry-pick in progress, abort that.
 813                  */
 814                 return rollback_single_pick();
 815         }
 816         if (!f)
 817                 return error(_("cannot open %s: %s"), filename,
 818                                                 strerror(errno));
 819         if (strbuf_getline(&buf, f, '\n')) {
 820                 error(_("cannot read %s: %s"), filename, ferror(f) ?
 821                         strerror(errno) : _("unexpected end of file"));
 822                 fclose(f);
 823                 goto fail;
 824         }
 825         fclose(f);
 826         if (get_sha1_hex(buf.buf, sha1) || buf.buf[40] != '\0') {
 827                 error(_("stored pre-cherry-pick HEAD file '%s' is corrupt"),
 828                         filename);
 829                 goto fail;
 830         }
 831         if (reset_for_rollback(sha1))
 832                 goto fail;
 833         remove_sequencer_state();
 834         strbuf_release(&buf);
 835         return 0;
 836 fail:
 837         strbuf_release(&buf);
 838         return -1;
 839 }
 840
 841 static void save_todo(struct commit_list *todo_list, struct replay_opts *opts)
 842 {
 843         const char *todo_file = git_path(SEQ_TODO_FILE);
 844         static struct lock_file todo_lock;
 845         struct strbuf buf = STRBUF_INIT;
 846         int fd;
 847
 848         fd = hold_lock_file_for_update(&todo_lock, todo_file, LOCK_DIE_ON_ERROR);
 849         if (format_todo(&buf, todo_list, opts) < 0)
 850                 die(_("Could not format %s."), todo_file);
 851         if (write_in_full(fd, buf.buf, buf.len) < 0) {
 852                 strbuf_release(&buf);
 853                 die_errno(_("Could not write to %s"), todo_file);
 854         }
 855         if (commit_lock_file(&todo_lock) < 0) {
 856                 strbuf_release(&buf);
 857                 die(_("Error wrapping up %s."), todo_file);
 858         }
 859         strbuf_release(&buf);
 860 }
 861
 862 static void save_opts(struct replay_opts *opts)
 863 {
 864         const char *opts_file = git_path(SEQ_OPTS_FILE);
 865
 866         if (opts->no_commit)
 867                 git_config_set_in_file(opts_file, "options.no-commit", "true");
 868         if (opts->edit)
 869                 git_config_set_in_file(opts_file, "options.edit", "true");
 870         if (opts->signoff)
 871                 git_config_set_in_file(opts_file, "options.signoff", "true");
 872         if (opts->record_origin)
 873                 git_config_set_in_file(opts_file, "options.record-origin", "true");
 874         if (opts->allow_ff)
 875                 git_config_set_in_file(opts_file, "options.allow-ff", "true");
 876         if (opts->mainline) {
 877                 struct strbuf buf = STRBUF_INIT;
 878                 strbuf_addf(&buf, "%d", opts->mainline);
 879                 git_config_set_in_file(opts_file, "options.mainline", buf.buf);
 880                 strbuf_release(&buf);
 881         }
 882         if (opts->strategy)
 883                 git_config_set_in_file(opts_file, "options.strategy", opts->strategy);
 884         if (opts->xopts) {
 885                 int i;
 886                 for (i = 0; i < opts->xopts_nr; i++)
 887                         git_config_set_multivar_in_file(opts_file,
 888                                                         "options.strategy-option",
 889                                                         opts->xopts[i], "^$", 0);
 890         }
 891 }
 892
 893 static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
 894 {
 895         struct commit_list *cur;
 896         int res;
 897
 898         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
 899         if (opts->allow_ff)
 900                 assert(!(opts->signoff || opts->no_commit ||
 901                                 opts->record_origin || opts->edit));
 902         read_and_refresh_cache(opts);
 903
 904         for (cur = todo_list; cur; cur = cur->next) {
 905                 save_todo(cur, opts);
 906                 res = do_pick_commit(cur->item, opts);
 907                 if (res)
 908                         return res;
 909         }
 910
 911         /*
 912          * Sequence of picks finished successfully; cleanup by
 913          * removing the .git/sequencer directory
 914          */
 915         remove_sequencer_state();
 916         return 0;
 917 }
 918
 919 static int continue_single_pick(void)
 920 {
 921         const char *argv[] = { "commit", NULL };
 922
 923         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
 924             !file_exists(git_path("REVERT_HEAD")))
 925                 return error(_("no cherry-pick or revert in progress"));
 926         return run_command_v_opt(argv, RUN_GIT_CMD);
 927 }
 928
 929 static int sequencer_continue(struct replay_opts *opts)
 930 {
 931         struct commit_list *todo_list = NULL;
 932
 933         if (!file_exists(git_path(SEQ_TODO_FILE)))
 934                 return continue_single_pick();
 935         read_populate_opts(&opts);
 936         read_populate_todo(&todo_list, opts);
 937
 938         /* Verify that the conflict has been resolved */
 939         if (file_exists(git_path("CHERRY_PICK_HEAD")) ||
 940             file_exists(git_path("REVERT_HEAD"))) {
 941                 int ret = continue_single_pick();
 942                 if (ret)
 943                         return ret;
 944         }
 945         if (index_differs_from("HEAD", 0))
 946                 return error_dirty_index(opts);
 947         todo_list = todo_list->next;
 948         return pick_commits(todo_list, opts);
 949 }
 950
 951 static int single_pick(struct commit *cmit, struct replay_opts *opts)
 952 {
 953         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
 954         return do_pick_commit(cmit, opts);
 955 }
 956
 957 int sequencer_pick_revisions(struct replay_opts *opts)
 958 {
 959         struct commit_list *todo_list = NULL;
 960         unsigned char sha1[20];
 961
 962         if (opts->subcommand == REPLAY_NONE)
 963                 assert(opts->revs);
 964
 965         read_and_refresh_cache(opts);
 966
 967         /*
 968          * Decide what to do depending on the arguments; a fresh
 969          * cherry-pick should be handled differently from an existing
 970          * one that is being continued
 971          */
 972         if (opts->subcommand == REPLAY_REMOVE_STATE) {
 973                 remove_sequencer_state();
 974                 return 0;
 975         }
 976         if (opts->subcommand == REPLAY_ROLLBACK)
 977                 return sequencer_rollback(opts);
 978         if (opts->subcommand == REPLAY_CONTINUE)
 979                 return sequencer_continue(opts);
 980
 981         /*
 982          * If we were called as "git cherry-pick <commit>", just
 983          * cherry-pick/revert it, set CHERRY_PICK_HEAD /
 984          * REVERT_HEAD, and don't touch the sequencer state.
 985          * This means it is possible to cherry-pick in the middle
 986          * of a cherry-pick sequence.
 987          */
 988         if (opts->revs->cmdline.nr == 1 &&
 989             opts->revs->cmdline.rev->whence == REV_CMD_REV &&
 990             opts->revs->no_walk &&
 991             !opts->revs->cmdline.rev->flags) {
 992                 struct commit *cmit;
 993                 if (prepare_revision_walk(opts->revs))
 994                         die(_("revision walk setup failed"));
 995                 cmit = get_revision(opts->revs);
 996                 if (!cmit || get_revision(opts->revs))
 997                         die("BUG: expected exactly one commit from walk");
 998                 return single_pick(cmit, opts);
 999         }
1000
1001         /*
1002          * Start a new cherry-pick/ revert sequence; but
1003          * first, make sure that an existing one isn't in
1004          * progress
1005          */
1006
1007         walk_revs_populate_todo(&todo_list, opts);
1008         if (create_seq_dir() < 0)
1009                 return -1;
1010         if (get_sha1("HEAD", sha1)) {
1011                 if (opts->action == REPLAY_REVERT)
1012                         return error(_("Can't revert as initial commit"));
1013                 return error(_("Can't cherry-pick into empty head"));
1014         }
1015         save_head(sha1_to_hex(sha1));
1016         save_opts(opts);
1017         return pick_commits(todo_list, opts);
1018 }
1019
1020 static int ends_rfc2822_footer(struct strbuf *sb, int ignore_footer)
1021 {
1022         int ch;
1023         int hit = 0;
1024         int i, j, k;
1025         int len = sb->len - ignore_footer;
1026         int first = 1;
1027         const char *buf = sb->buf;
1028
1029         for (i = len - 1; i > 0; i--) {
1030                 if (hit && buf[i] == '\n')
1031                         break;
1032                 hit = (buf[i] == '\n');
1033         }
1034
1035         while (i < len - 1 && buf[i] == '\n')
1036                 i++;
1037
1038         for (; i < len; i = k) {
1039                 for (k = i; k < len && buf[k] != '\n'; k++)
1040                         ; /* do nothing */
1041                 k++;
1042
1043                 if ((buf[k] == ' ' || buf[k] == '\t') && !first)
1044                         continue;
1045
1046                 first = 0;
1047
1048                 for (j = 0; i + j < len; j++) {
1049                         ch = buf[i + j];
1050                         if (ch == ':')
1051                                 break;
1052                         if (isalnum(ch) ||
1053                             (ch == '-'))
1054                                 continue;
1055                         return 0;
1056                 }
1057         }
1058         return 1;
1059 }
1060
1061 void append_signoff(struct strbuf *msgbuf, int ignore_footer)
1062 {
1063         struct strbuf sob = STRBUF_INIT;
1064         int i;
1065
1066         strbuf_addstr(&sob, sign_off_header);
1067         strbuf_addstr(&sob, fmt_name(getenv("GIT_COMMITTER_NAME"),
1068                                 getenv("GIT_COMMITTER_EMAIL")));
1069         strbuf_addch(&sob, '\n');
1070         for (i = msgbuf->len - 1 - ignore_footer; i > 0 && msgbuf->buf[i - 1] != '\n'; i--)
1071                 ; /* do nothing */
1072         if (prefixcmp(msgbuf->buf + i, sob.buf)) {
1073                 if (!i || !ends_rfc2822_footer(msgbuf, ignore_footer))
1074                         strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0, "\n", 1);
1075                 strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0, sob.buf, sob.len);
1076         }
1077         strbuf_release(&sob);
1078 }