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