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 {
 296         struct argv_array array;
 297         int rc;
 298
 299         argv_array_init(&array);
 300         argv_array_push(&array, "commit");
 301         argv_array_push(&array, "-n");
 302
 303         if (opts->signoff)
 304                 argv_array_push(&array, "-s");
 305         if (!opts->edit) {
 306                 argv_array_push(&array, "-F");
 307                 argv_array_push(&array, defmsg);
 308         }
 309
 310         if (opts->allow_empty)
 311                 argv_array_push(&array, "--allow-empty");
 312
 313         rc = run_command_v_opt(array.argv, RUN_GIT_CMD);
 314         argv_array_clear(&array);
 315         return rc;
 316 }
 317
 318 static int is_original_commit_empty(struct commit *commit)
 319 {
 320         const unsigned char *ptree_sha1;
 321
 322         if (parse_commit(commit))
 323                 return error(_("Could not parse commit %s\n"),
 324                              sha1_to_hex(commit->object.sha1));
 325         if (commit->parents) {
 326                 struct commit *parent = commit->parents->item;
 327                 if (parse_commit(parent))
 328                         return error(_("Could not parse parent commit %s\n"),
 329                                 sha1_to_hex(parent->object.sha1));
 330                 ptree_sha1 = parent->tree->object.sha1;
 331         } else {
 332                 ptree_sha1 = EMPTY_TREE_SHA1_BIN; /* commit is root */
 333         }
 334
 335         return !hashcmp(ptree_sha1, commit->tree->object.sha1);
 336 }
 337
 338 static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
 339 {
 340         unsigned char head[20];
 341         struct commit *base, *next, *parent;
 342         const char *base_label, *next_label;
 343         struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
 344         char *defmsg = NULL;
 345         struct strbuf msgbuf = STRBUF_INIT;
 346         int res;
 347         int empty_commit;
 348         int index_unchanged;
 349
 350         if (opts->no_commit) {
 351                 /*
 352                  * We do not intend to commit immediately.  We just want to
 353                  * merge the differences in, so let's compute the tree
 354                  * that represents the "current" state for merge-recursive
 355                  * to work on.
 356                  */
 357                 if (write_cache_as_tree(head, 0, NULL))
 358                         die (_("Your index file is unmerged."));
 359         } else {
 360                 if (get_sha1("HEAD", head))
 361                         return error(_("You do not have a valid HEAD"));
 362                 if (index_differs_from("HEAD", 0))
 363                         return error_dirty_index(opts);
 364         }
 365         discard_cache();
 366
 367         if (!commit->parents) {
 368                 parent = NULL;
 369         }
 370         else if (commit->parents->next) {
 371                 /* Reverting or cherry-picking a merge commit */
 372                 int cnt;
 373                 struct commit_list *p;
 374
 375                 if (!opts->mainline)
 376                         return error(_("Commit %s is a merge but no -m option was given."),
 377                                 sha1_to_hex(commit->object.sha1));
 378
 379                 for (cnt = 1, p = commit->parents;
 380                      cnt != opts->mainline && p;
 381                      cnt++)
 382                         p = p->next;
 383                 if (cnt != opts->mainline || !p)
 384                         return error(_("Commit %s does not have parent %d"),
 385                                 sha1_to_hex(commit->object.sha1), opts->mainline);
 386                 parent = p->item;
 387         } else if (0 < opts->mainline)
 388                 return error(_("Mainline was specified but commit %s is not a merge."),
 389                         sha1_to_hex(commit->object.sha1));
 390         else
 391                 parent = commit->parents->item;
 392
 393         if (opts->allow_ff && parent && !hashcmp(parent->object.sha1, head))
 394                 return fast_forward_to(commit->object.sha1, head);
 395
 396         if (parent && parse_commit(parent) < 0)
 397                 /* TRANSLATORS: The first %s will be "revert" or
 398                    "cherry-pick", the second %s a SHA1 */
 399                 return error(_("%s: cannot parse parent commit %s"),
 400                         action_name(opts), sha1_to_hex(parent->object.sha1));
 401
 402         if (get_message(commit, &msg) != 0)
 403                 return error(_("Cannot get commit message for %s"),
 404                         sha1_to_hex(commit->object.sha1));
 405
 406         /*
 407          * "commit" is an existing commit.  We would want to apply
 408          * the difference it introduces since its first parent "prev"
 409          * on top of the current HEAD if we are cherry-pick.  Or the
 410          * reverse of it if we are revert.
 411          */
 412
 413         defmsg = git_pathdup("MERGE_MSG");
 414
 415         if (opts->action == REPLAY_REVERT) {
 416                 base = commit;
 417                 base_label = msg.label;
 418                 next = parent;
 419                 next_label = msg.parent_label;
 420                 strbuf_addstr(&msgbuf, "Revert \"");
 421                 strbuf_addstr(&msgbuf, msg.subject);
 422                 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
 423                 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 424
 425                 if (commit->parents && commit->parents->next) {
 426                         strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
 427                         strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
 428                 }
 429                 strbuf_addstr(&msgbuf, ".\n");
 430         } else {
 431                 const char *p;
 432
 433                 base = parent;
 434                 base_label = msg.parent_label;
 435                 next = commit;
 436                 next_label = msg.label;
 437
 438                 /*
 439                  * Append the commit log message to msgbuf; it starts
 440                  * after the tree, parent, author, committer
 441                  * information followed by "\n\n".
 442                  */
 443                 p = strstr(msg.message, "\n\n");
 444                 if (p) {
 445                         p += 2;
 446                         strbuf_addstr(&msgbuf, p);
 447                 }
 448
 449                 if (opts->record_origin) {
 450                         strbuf_addstr(&msgbuf, "(cherry picked from commit ");
 451                         strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 452                         strbuf_addstr(&msgbuf, ")\n");
 453                 }
 454         }
 455
 456         if (!opts->strategy || !strcmp(opts->strategy, "recursive") || opts->action == REPLAY_REVERT) {
 457                 res = do_recursive_merge(base, next, base_label, next_label,
 458                                          head, &msgbuf, opts);
 459                 write_message(&msgbuf, defmsg);
 460         } else {
 461                 struct commit_list *common = NULL;
 462                 struct commit_list *remotes = NULL;
 463
 464                 write_message(&msgbuf, defmsg);
 465
 466                 commit_list_insert(base, &common);
 467                 commit_list_insert(next, &remotes);
 468                 res = try_merge_command(opts->strategy, opts->xopts_nr, opts->xopts,
 469                                         common, sha1_to_hex(head), remotes);
 470                 free_commit_list(common);
 471                 free_commit_list(remotes);
 472         }
 473
 474         empty_commit = is_original_commit_empty(commit);
 475         if (empty_commit < 0)
 476                 return empty_commit;
 477
 478         /*
 479          * If the merge was clean or if it failed due to conflict, we write
 480          * CHERRY_PICK_HEAD for the subsequent invocation of commit to use.
 481          * However, if the merge did not even start, then we don't want to
 482          * write it at all.
 483          */
 484         if (opts->action == REPLAY_PICK && !opts->no_commit && (res == 0 || res == 1))
 485                 write_cherry_pick_head(commit, "CHERRY_PICK_HEAD");
 486         if (opts->action == REPLAY_REVERT && ((opts->no_commit && res == 0) || res == 1))
 487                 write_cherry_pick_head(commit, "REVERT_HEAD");
 488
 489         if (res) {
 490                 error(opts->action == REPLAY_REVERT
 491                       ? _("could not revert %s... %s")
 492                       : _("could not apply %s... %s"),
 493                       find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV),
 494                       msg.subject);
 495                 print_advice(res == 1, opts);
 496                 rerere(opts->allow_rerere_auto);
 497         } else {
 498                 index_unchanged = is_index_unchanged();
 499                 /*
 500                  * If index_unchanged is less than 0, that indicates we either
 501                  * couldn't parse HEAD or the index, so error out here.
 502                  */
 503                 if (index_unchanged < 0)
 504                         return index_unchanged;
 505
 506                 if (!empty_commit && !opts->keep_redundant_commits && index_unchanged)
 507                         /*
 508                          * The head tree and the index match
 509                          * meaning the commit is empty.  Since it wasn't created
 510                          * empty (based on the previous test), we can conclude
 511                          * the commit has been made redundant.  Since we don't
 512                          * want to keep redundant commits, we can just return
 513                          * here, skipping this commit
 514                          */
 515                         return 0;
 516
 517                 if (!opts->no_commit)
 518                         res = run_git_commit(defmsg, opts);
 519         }
 520
 521         free_message(&msg);
 522         free(defmsg);
 523
 524         return res;
 525 }
 526
 527 static void prepare_revs(struct replay_opts *opts)
 528 {
 529         if (opts->action != REPLAY_REVERT)
 530                 opts->revs->reverse ^= 1;
 531
 532         if (prepare_revision_walk(opts->revs))
 533                 die(_("revision walk setup failed"));
 534
 535         if (!opts->revs->commits)
 536                 die(_("empty commit set passed"));
 537 }
 538
 539 static void read_and_refresh_cache(struct replay_opts *opts)
 540 {
 541         static struct lock_file index_lock;
 542         int index_fd = hold_locked_index(&index_lock, 0);
 543         if (read_index_preload(&the_index, NULL) < 0)
 544                 die(_("git %s: failed to read the index"), action_name(opts));
 545         refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
 546         if (the_index.cache_changed) {
 547                 if (write_index(&the_index, index_fd) ||
 548                     commit_locked_index(&index_lock))
 549                         die(_("git %s: failed to refresh the index"), action_name(opts));
 550         }
 551         rollback_lock_file(&index_lock);
 552 }
 553
 554 static int format_todo(struct strbuf *buf, struct commit_list *todo_list,
 555                 struct replay_opts *opts)
 556 {
 557         struct commit_list *cur = NULL;
 558         const char *sha1_abbrev = NULL;
 559         const char *action_str = opts->action == REPLAY_REVERT ? "revert" : "pick";
 560         const char *subject;
 561         int subject_len;
 562
 563         for (cur = todo_list; cur; cur = cur->next) {
 564                 sha1_abbrev = find_unique_abbrev(cur->item->object.sha1, DEFAULT_ABBREV);
 565                 subject_len = find_commit_subject(cur->item->buffer, &subject);
 566                 strbuf_addf(buf, "%s %s %.*s\n", action_str, sha1_abbrev,
 567                         subject_len, subject);
 568         }
 569         return 0;
 570 }
 571
 572 static struct commit *parse_insn_line(char *bol, char *eol, struct replay_opts *opts)
 573 {
 574         unsigned char commit_sha1[20];
 575         enum replay_action action;
 576         char *end_of_object_name;
 577         int saved, status, padding;
 578
 579         if (!prefixcmp(bol, "pick")) {
 580                 action = REPLAY_PICK;
 581                 bol += strlen("pick");
 582         } else if (!prefixcmp(bol, "revert")) {
 583                 action = REPLAY_REVERT;
 584                 bol += strlen("revert");
 585         } else
 586                 return NULL;
 587
 588         /* Eat up extra spaces/ tabs before object name */
 589         padding = strspn(bol, " \t");
 590         if (!padding)
 591                 return NULL;
 592         bol += padding;
 593
 594         end_of_object_name = bol + strcspn(bol, " \t\n");
 595         saved = *end_of_object_name;
 596         *end_of_object_name = '\0';
 597         status = get_sha1(bol, commit_sha1);
 598         *end_of_object_name = saved;
 599
 600         /*
 601          * Verify that the action matches up with the one in
 602          * opts; we don't support arbitrary instructions
 603          */
 604         if (action != opts->action) {
 605                 const char *action_str;
 606                 action_str = action == REPLAY_REVERT ? "revert" : "cherry-pick";
 607                 error(_("Cannot %s during a %s"), action_str, action_name(opts));
 608                 return NULL;
 609         }
 610
 611         if (status < 0)
 612                 return NULL;
 613
 614         return lookup_commit_reference(commit_sha1);
 615 }
 616
 617 static int parse_insn_buffer(char *buf, struct commit_list **todo_list,
 618                         struct replay_opts *opts)
 619 {
 620         struct commit_list **next = todo_list;
 621         struct commit *commit;
 622         char *p = buf;
 623         int i;
 624
 625         for (i = 1; *p; i++) {
 626                 char *eol = strchrnul(p, '\n');
 627                 commit = parse_insn_line(p, eol, opts);
 628                 if (!commit)
 629                         return error(_("Could not parse line %d."), i);
 630                 next = commit_list_append(commit, next);
 631                 p = *eol ? eol + 1 : eol;
 632         }
 633         if (!*todo_list)
 634                 return error(_("No commits parsed."));
 635         return 0;
 636 }
 637
 638 static void read_populate_todo(struct commit_list **todo_list,
 639                         struct replay_opts *opts)
 640 {
 641         const char *todo_file = git_path(SEQ_TODO_FILE);
 642         struct strbuf buf = STRBUF_INIT;
 643         int fd, res;
 644
 645         fd = open(todo_file, O_RDONLY);
 646         if (fd < 0)
 647                 die_errno(_("Could not open %s"), todo_file);
 648         if (strbuf_read(&buf, fd, 0) < 0) {
 649                 close(fd);
 650                 strbuf_release(&buf);
 651                 die(_("Could not read %s."), todo_file);
 652         }
 653         close(fd);
 654
 655         res = parse_insn_buffer(buf.buf, todo_list, opts);
 656         strbuf_release(&buf);
 657         if (res)
 658                 die(_("Unusable instruction sheet: %s"), todo_file);
 659 }
 660
 661 static int populate_opts_cb(const char *key, const char *value, void *data)
 662 {
 663         struct replay_opts *opts = data;
 664         int error_flag = 1;
 665
 666         if (!value)
 667                 error_flag = 0;
 668         else if (!strcmp(key, "options.no-commit"))
 669                 opts->no_commit = git_config_bool_or_int(key, value, &error_flag);
 670         else if (!strcmp(key, "options.edit"))
 671                 opts->edit = git_config_bool_or_int(key, value, &error_flag);
 672         else if (!strcmp(key, "options.signoff"))
 673                 opts->signoff = git_config_bool_or_int(key, value, &error_flag);
 674         else if (!strcmp(key, "options.record-origin"))
 675                 opts->record_origin = git_config_bool_or_int(key, value, &error_flag);
 676         else if (!strcmp(key, "options.allow-ff"))
 677                 opts->allow_ff = git_config_bool_or_int(key, value, &error_flag);
 678         else if (!strcmp(key, "options.mainline"))
 679                 opts->mainline = git_config_int(key, value);
 680         else if (!strcmp(key, "options.strategy"))
 681                 git_config_string(&opts->strategy, key, value);
 682         else if (!strcmp(key, "options.strategy-option")) {
 683                 ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
 684                 opts->xopts[opts->xopts_nr++] = xstrdup(value);
 685         } else
 686                 return error(_("Invalid key: %s"), key);
 687
 688         if (!error_flag)
 689                 return error(_("Invalid value for %s: %s"), key, value);
 690
 691         return 0;
 692 }
 693
 694 static void read_populate_opts(struct replay_opts **opts_ptr)
 695 {
 696         const char *opts_file = git_path(SEQ_OPTS_FILE);
 697
 698         if (!file_exists(opts_file))
 699                 return;
 700         if (git_config_from_file(populate_opts_cb, opts_file, *opts_ptr) < 0)
 701                 die(_("Malformed options sheet: %s"), opts_file);
 702 }
 703
 704 static void walk_revs_populate_todo(struct commit_list **todo_list,
 705                                 struct replay_opts *opts)
 706 {
 707         struct commit *commit;
 708         struct commit_list **next;
 709
 710         prepare_revs(opts);
 711
 712         next = todo_list;
 713         while ((commit = get_revision(opts->revs)))
 714                 next = commit_list_append(commit, next);
 715 }
 716
 717 static int create_seq_dir(void)
 718 {
 719         const char *seq_dir = git_path(SEQ_DIR);
 720
 721         if (file_exists(seq_dir)) {
 722                 error(_("a cherry-pick or revert is already in progress"));
 723                 advise(_("try \"git cherry-pick (--continue | --quit | --abort)\""));
 724                 return -1;
 725         }
 726         else if (mkdir(seq_dir, 0777) < 0)
 727                 die_errno(_("Could not create sequencer directory %s"), seq_dir);
 728         return 0;
 729 }
 730
 731 static void save_head(const char *head)
 732 {
 733         const char *head_file = git_path(SEQ_HEAD_FILE);
 734         static struct lock_file head_lock;
 735         struct strbuf buf = STRBUF_INIT;
 736         int fd;
 737
 738         fd = hold_lock_file_for_update(&head_lock, head_file, LOCK_DIE_ON_ERROR);
 739         strbuf_addf(&buf, "%s\n", head);
 740         if (write_in_full(fd, buf.buf, buf.len) < 0)
 741                 die_errno(_("Could not write to %s"), head_file);
 742         if (commit_lock_file(&head_lock) < 0)
 743                 die(_("Error wrapping up %s."), head_file);
 744 }
 745
 746 static int reset_for_rollback(const unsigned char *sha1)
 747 {
 748         const char *argv[4];    /* reset --merge <arg> + NULL */
 749         argv[0] = "reset";
 750         argv[1] = "--merge";
 751         argv[2] = sha1_to_hex(sha1);
 752         argv[3] = NULL;
 753         return run_command_v_opt(argv, RUN_GIT_CMD);
 754 }
 755
 756 static int rollback_single_pick(void)
 757 {
 758         unsigned char head_sha1[20];
 759
 760         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
 761             !file_exists(git_path("REVERT_HEAD")))
 762                 return error(_("no cherry-pick or revert in progress"));
 763         if (read_ref_full("HEAD", head_sha1, 0, NULL))
 764                 return error(_("cannot resolve HEAD"));
 765         if (is_null_sha1(head_sha1))
 766                 return error(_("cannot abort from a branch yet to be born"));
 767         return reset_for_rollback(head_sha1);
 768 }
 769
 770 static int sequencer_rollback(struct replay_opts *opts)
 771 {
 772         const char *filename;
 773         FILE *f;
 774         unsigned char sha1[20];
 775         struct strbuf buf = STRBUF_INIT;
 776
 777         filename = git_path(SEQ_HEAD_FILE);
 778         f = fopen(filename, "r");
 779         if (!f && errno == ENOENT) {
 780                 /*
 781                  * There is no multiple-cherry-pick in progress.
 782                  * If CHERRY_PICK_HEAD or REVERT_HEAD indicates
 783                  * a single-cherry-pick in progress, abort that.
 784                  */
 785                 return rollback_single_pick();
 786         }
 787         if (!f)
 788                 return error(_("cannot open %s: %s"), filename,
 789                                                 strerror(errno));
 790         if (strbuf_getline(&buf, f, '\n')) {
 791                 error(_("cannot read %s: %s"), filename, ferror(f) ?
 792                         strerror(errno) : _("unexpected end of file"));
 793                 fclose(f);
 794                 goto fail;
 795         }
 796         fclose(f);
 797         if (get_sha1_hex(buf.buf, sha1) || buf.buf[40] != '\0') {
 798                 error(_("stored pre-cherry-pick HEAD file '%s' is corrupt"),
 799                         filename);
 800                 goto fail;
 801         }
 802         if (reset_for_rollback(sha1))
 803                 goto fail;
 804         remove_sequencer_state();
 805         strbuf_release(&buf);
 806         return 0;
 807 fail:
 808         strbuf_release(&buf);
 809         return -1;
 810 }
 811
 812 static void save_todo(struct commit_list *todo_list, struct replay_opts *opts)
 813 {
 814         const char *todo_file = git_path(SEQ_TODO_FILE);
 815         static struct lock_file todo_lock;
 816         struct strbuf buf = STRBUF_INIT;
 817         int fd;
 818
 819         fd = hold_lock_file_for_update(&todo_lock, todo_file, LOCK_DIE_ON_ERROR);
 820         if (format_todo(&buf, todo_list, opts) < 0)
 821                 die(_("Could not format %s."), todo_file);
 822         if (write_in_full(fd, buf.buf, buf.len) < 0) {
 823                 strbuf_release(&buf);
 824                 die_errno(_("Could not write to %s"), todo_file);
 825         }
 826         if (commit_lock_file(&todo_lock) < 0) {
 827                 strbuf_release(&buf);
 828                 die(_("Error wrapping up %s."), todo_file);
 829         }
 830         strbuf_release(&buf);
 831 }
 832
 833 static void save_opts(struct replay_opts *opts)
 834 {
 835         const char *opts_file = git_path(SEQ_OPTS_FILE);
 836
 837         if (opts->no_commit)
 838                 git_config_set_in_file(opts_file, "options.no-commit", "true");
 839         if (opts->edit)
 840                 git_config_set_in_file(opts_file, "options.edit", "true");
 841         if (opts->signoff)
 842                 git_config_set_in_file(opts_file, "options.signoff", "true");
 843         if (opts->record_origin)
 844                 git_config_set_in_file(opts_file, "options.record-origin", "true");
 845         if (opts->allow_ff)
 846                 git_config_set_in_file(opts_file, "options.allow-ff", "true");
 847         if (opts->mainline) {
 848                 struct strbuf buf = STRBUF_INIT;
 849                 strbuf_addf(&buf, "%d", opts->mainline);
 850                 git_config_set_in_file(opts_file, "options.mainline", buf.buf);
 851                 strbuf_release(&buf);
 852         }
 853         if (opts->strategy)
 854                 git_config_set_in_file(opts_file, "options.strategy", opts->strategy);
 855         if (opts->xopts) {
 856                 int i;
 857                 for (i = 0; i < opts->xopts_nr; i++)
 858                         git_config_set_multivar_in_file(opts_file,
 859                                                         "options.strategy-option",
 860                                                         opts->xopts[i], "^$", 0);
 861         }
 862 }
 863
 864 static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
 865 {
 866         struct commit_list *cur;
 867         int res;
 868
 869         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
 870         if (opts->allow_ff)
 871                 assert(!(opts->signoff || opts->no_commit ||
 872                                 opts->record_origin || opts->edit));
 873         read_and_refresh_cache(opts);
 874
 875         for (cur = todo_list; cur; cur = cur->next) {
 876                 save_todo(cur, opts);
 877                 res = do_pick_commit(cur->item, opts);
 878                 if (res)
 879                         return res;
 880         }
 881
 882         /*
 883          * Sequence of picks finished successfully; cleanup by
 884          * removing the .git/sequencer directory
 885          */
 886         remove_sequencer_state();
 887         return 0;
 888 }
 889
 890 static int continue_single_pick(void)
 891 {
 892         const char *argv[] = { "commit", NULL };
 893
 894         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
 895             !file_exists(git_path("REVERT_HEAD")))
 896                 return error(_("no cherry-pick or revert in progress"));
 897         return run_command_v_opt(argv, RUN_GIT_CMD);
 898 }
 899
 900 static int sequencer_continue(struct replay_opts *opts)
 901 {
 902         struct commit_list *todo_list = NULL;
 903
 904         if (!file_exists(git_path(SEQ_TODO_FILE)))
 905                 return continue_single_pick();
 906         read_populate_opts(&opts);
 907         read_populate_todo(&todo_list, opts);
 908
 909         /* Verify that the conflict has been resolved */
 910         if (file_exists(git_path("CHERRY_PICK_HEAD")) ||
 911             file_exists(git_path("REVERT_HEAD"))) {
 912                 int ret = continue_single_pick();
 913                 if (ret)
 914                         return ret;
 915         }
 916         if (index_differs_from("HEAD", 0))
 917                 return error_dirty_index(opts);
 918         todo_list = todo_list->next;
 919         return pick_commits(todo_list, opts);
 920 }
 921
 922 static int single_pick(struct commit *cmit, struct replay_opts *opts)
 923 {
 924         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
 925         return do_pick_commit(cmit, opts);
 926 }
 927
 928 int sequencer_pick_revisions(struct replay_opts *opts)
 929 {
 930         struct commit_list *todo_list = NULL;
 931         unsigned char sha1[20];
 932
 933         if (opts->subcommand == REPLAY_NONE)
 934                 assert(opts->revs);
 935
 936         read_and_refresh_cache(opts);
 937
 938         /*
 939          * Decide what to do depending on the arguments; a fresh
 940          * cherry-pick should be handled differently from an existing
 941          * one that is being continued
 942          */
 943         if (opts->subcommand == REPLAY_REMOVE_STATE) {
 944                 remove_sequencer_state();
 945                 return 0;
 946         }
 947         if (opts->subcommand == REPLAY_ROLLBACK)
 948                 return sequencer_rollback(opts);
 949         if (opts->subcommand == REPLAY_CONTINUE)
 950                 return sequencer_continue(opts);
 951
 952         /*
 953          * If we were called as "git cherry-pick <commit>", just
 954          * cherry-pick/revert it, set CHERRY_PICK_HEAD /
 955          * REVERT_HEAD, and don't touch the sequencer state.
 956          * This means it is possible to cherry-pick in the middle
 957          * of a cherry-pick sequence.
 958          */
 959         if (opts->revs->cmdline.nr == 1 &&
 960             opts->revs->cmdline.rev->whence == REV_CMD_REV &&
 961             opts->revs->no_walk &&
 962             !opts->revs->cmdline.rev->flags) {
 963                 struct commit *cmit;
 964                 if (prepare_revision_walk(opts->revs))
 965                         die(_("revision walk setup failed"));
 966                 cmit = get_revision(opts->revs);
 967                 if (!cmit || get_revision(opts->revs))
 968                         die("BUG: expected exactly one commit from walk");
 969                 return single_pick(cmit, opts);
 970         }
 971
 972         /*
 973          * Start a new cherry-pick/ revert sequence; but
 974          * first, make sure that an existing one isn't in
 975          * progress
 976          */
 977
 978         walk_revs_populate_todo(&todo_list, opts);
 979         if (create_seq_dir() < 0)
 980                 return -1;
 981         if (get_sha1("HEAD", sha1)) {
 982                 if (opts->action == REPLAY_REVERT)
 983                         return error(_("Can't revert as initial commit"));
 984                 return error(_("Can't cherry-pick into empty head"));
 985         }
 986         save_head(sha1_to_hex(sha1));
 987         save_opts(opts);
 988         return pick_commits(todo_list, opts);
 989 }