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

   1 #include "cache.h"
   2 #include "sequencer.h"
   3 #include "dir.h"
   4 #include "object.h"
   5 #include "commit.h"
   6 #include "tag.h"
   7 #include "run-command.h"
   8 #include "exec_cmd.h"
   9 #include "utf8.h"
  10 #include "cache-tree.h"
  11 #include "diff.h"
  12 #include "revision.h"
  13 #include "rerere.h"
  14 #include "merge-recursive.h"
  15 #include "refs.h"
  16 #include "argv-array.h"
  17
  18 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
  19
  20 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         if (opts->allow_empty_message)
 315                 argv_array_push(&array, "--allow-empty-message");
 316
 317         rc = run_command_v_opt(array.argv, RUN_GIT_CMD);
 318         argv_array_clear(&array);
 319         return rc;
 320 }
 321
 322 static int is_original_commit_empty(struct commit *commit)
 323 {
 324         const unsigned char *ptree_sha1;
 325
 326         if (parse_commit(commit))
 327                 return error(_("Could not parse commit %s\n"),
 328                              sha1_to_hex(commit->object.sha1));
 329         if (commit->parents) {
 330                 struct commit *parent = commit->parents->item;
 331                 if (parse_commit(parent))
 332                         return error(_("Could not parse parent commit %s\n"),
 333                                 sha1_to_hex(parent->object.sha1));
 334                 ptree_sha1 = parent->tree->object.sha1;
 335         } else {
 336                 ptree_sha1 = EMPTY_TREE_SHA1_BIN; /* commit is root */
 337         }
 338
 339         return !hashcmp(ptree_sha1, commit->tree->object.sha1);
 340 }
 341
 342 /*
 343  * Do we run "git commit" with "--allow-empty"?
 344  */
 345 static int allow_empty(struct replay_opts *opts, struct commit *commit)
 346 {
 347         int index_unchanged, empty_commit;
 348
 349         /*
 350          * Three cases:
 351          *
 352          * (1) we do not allow empty at all and error out.
 353          *
 354          * (2) we allow ones that were initially empty, but
 355          * forbid the ones that become empty;
 356          *
 357          * (3) we allow both.
 358          */
 359         if (!opts->allow_empty)
 360                 return 0; /* let "git commit" barf as necessary */
 361
 362         index_unchanged = is_index_unchanged();
 363         if (index_unchanged < 0)
 364                 return index_unchanged;
 365         if (!index_unchanged)
 366                 return 0; /* we do not have to say --allow-empty */
 367
 368         if (opts->keep_redundant_commits)
 369                 return 1;
 370
 371         empty_commit = is_original_commit_empty(commit);
 372         if (empty_commit < 0)
 373                 return empty_commit;
 374         if (!empty_commit)
 375                 return 0;
 376         else
 377                 return 1;
 378 }
 379
 380 static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
 381 {
 382         unsigned char head[20];
 383         struct commit *base, *next, *parent;
 384         const char *base_label, *next_label;
 385         struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
 386         char *defmsg = NULL;
 387         struct strbuf msgbuf = STRBUF_INIT;
 388         int res;
 389
 390         if (opts->no_commit) {
 391                 /*
 392                  * We do not intend to commit immediately.  We just want to
 393                  * merge the differences in, so let's compute the tree
 394                  * that represents the "current" state for merge-recursive
 395                  * to work on.
 396                  */
 397                 if (write_cache_as_tree(head, 0, NULL))
 398                         die (_("Your index file is unmerged."));
 399         } else {
 400                 if (get_sha1("HEAD", head))
 401                         return error(_("You do not have a valid HEAD"));
 402                 if (index_differs_from("HEAD", 0))
 403                         return error_dirty_index(opts);
 404         }
 405         discard_cache();
 406
 407         if (!commit->parents) {
 408                 parent = NULL;
 409         }
 410         else if (commit->parents->next) {
 411                 /* Reverting or cherry-picking a merge commit */
 412                 int cnt;
 413                 struct commit_list *p;
 414
 415                 if (!opts->mainline)
 416                         return error(_("Commit %s is a merge but no -m option was given."),
 417                                 sha1_to_hex(commit->object.sha1));
 418
 419                 for (cnt = 1, p = commit->parents;
 420                      cnt != opts->mainline && p;
 421                      cnt++)
 422                         p = p->next;
 423                 if (cnt != opts->mainline || !p)
 424                         return error(_("Commit %s does not have parent %d"),
 425                                 sha1_to_hex(commit->object.sha1), opts->mainline);
 426                 parent = p->item;
 427         } else if (0 < opts->mainline)
 428                 return error(_("Mainline was specified but commit %s is not a merge."),
 429                         sha1_to_hex(commit->object.sha1));
 430         else
 431                 parent = commit->parents->item;
 432
 433         if (opts->allow_ff && parent && !hashcmp(parent->object.sha1, head))
 434                 return fast_forward_to(commit->object.sha1, head);
 435
 436         if (parent && parse_commit(parent) < 0)
 437                 /* TRANSLATORS: The first %s will be "revert" or
 438                    "cherry-pick", the second %s a SHA1 */
 439                 return error(_("%s: cannot parse parent commit %s"),
 440                         action_name(opts), sha1_to_hex(parent->object.sha1));
 441
 442         if (get_message(commit, &msg) != 0)
 443                 return error(_("Cannot get commit message for %s"),
 444                         sha1_to_hex(commit->object.sha1));
 445
 446         /*
 447          * "commit" is an existing commit.  We would want to apply
 448          * the difference it introduces since its first parent "prev"
 449          * on top of the current HEAD if we are cherry-pick.  Or the
 450          * reverse of it if we are revert.
 451          */
 452
 453         defmsg = git_pathdup("MERGE_MSG");
 454
 455         if (opts->action == REPLAY_REVERT) {
 456                 base = commit;
 457                 base_label = msg.label;
 458                 next = parent;
 459                 next_label = msg.parent_label;
 460                 strbuf_addstr(&msgbuf, "Revert \"");
 461                 strbuf_addstr(&msgbuf, msg.subject);
 462                 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
 463                 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 464
 465                 if (commit->parents && commit->parents->next) {
 466                         strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
 467                         strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
 468                 }
 469                 strbuf_addstr(&msgbuf, ".\n");
 470         } else {
 471                 const char *p;
 472
 473                 base = parent;
 474                 base_label = msg.parent_label;
 475                 next = commit;
 476                 next_label = msg.label;
 477
 478                 /*
 479                  * Append the commit log message to msgbuf; it starts
 480                  * after the tree, parent, author, committer
 481                  * information followed by "\n\n".
 482                  */
 483                 p = strstr(msg.message, "\n\n");
 484                 if (p) {
 485                         p += 2;
 486                         strbuf_addstr(&msgbuf, p);
 487                 }
 488
 489                 if (opts->record_origin) {
 490                         strbuf_addstr(&msgbuf, "(cherry picked from commit ");
 491                         strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 492                         strbuf_addstr(&msgbuf, ")\n");
 493                 }
 494         }
 495
 496         if (!opts->strategy || !strcmp(opts->strategy, "recursive") || opts->action == REPLAY_REVERT) {
 497                 res = do_recursive_merge(base, next, base_label, next_label,
 498                                          head, &msgbuf, opts);
 499                 write_message(&msgbuf, defmsg);
 500         } else {
 501                 struct commit_list *common = NULL;
 502                 struct commit_list *remotes = NULL;
 503
 504                 write_message(&msgbuf, defmsg);
 505
 506                 commit_list_insert(base, &common);
 507                 commit_list_insert(next, &remotes);
 508                 res = try_merge_command(opts->strategy, opts->xopts_nr, opts->xopts,
 509                                         common, sha1_to_hex(head), remotes);
 510                 free_commit_list(common);
 511                 free_commit_list(remotes);
 512         }
 513
 514         /*
 515          * If the merge was clean or if it failed due to conflict, we write
 516          * CHERRY_PICK_HEAD for the subsequent invocation of commit to use.
 517          * However, if the merge did not even start, then we don't want to
 518          * write it at all.
 519          */
 520         if (opts->action == REPLAY_PICK && !opts->no_commit && (res == 0 || res == 1))
 521                 write_cherry_pick_head(commit, "CHERRY_PICK_HEAD");
 522         if (opts->action == REPLAY_REVERT && ((opts->no_commit && res == 0) || res == 1))
 523                 write_cherry_pick_head(commit, "REVERT_HEAD");
 524
 525         if (res) {
 526                 error(opts->action == REPLAY_REVERT
 527                       ? _("could not revert %s... %s")
 528                       : _("could not apply %s... %s"),
 529                       find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV),
 530                       msg.subject);
 531                 print_advice(res == 1, opts);
 532                 rerere(opts->allow_rerere_auto);
 533         } else {
 534                 int allow = allow_empty(opts, commit);
 535                 if (allow < 0)
 536                         return allow;
 537                 if (!opts->no_commit)
 538                         res = run_git_commit(defmsg, opts, allow);
 539         }
 540
 541         free_message(&msg);
 542         free(defmsg);
 543
 544         return res;
 545 }
 546
 547 static void prepare_revs(struct replay_opts *opts)
 548 {
 549         /*
 550          * picking (but not reverting) ranges (but not individual revisions)
 551          * should be done in reverse
 552          */
 553         if (opts->action == REPLAY_PICK && !opts->revs->no_walk)
 554                 opts->revs->reverse ^= 1;
 555
 556         if (prepare_revision_walk(opts->revs))
 557                 die(_("revision walk setup failed"));
 558
 559         if (!opts->revs->commits)
 560                 die(_("empty commit set passed"));
 561 }
 562
 563 static void read_and_refresh_cache(struct replay_opts *opts)
 564 {
 565         static struct lock_file index_lock;
 566         int index_fd = hold_locked_index(&index_lock, 0);
 567         if (read_index_preload(&the_index, NULL) < 0)
 568                 die(_("git %s: failed to read the index"), action_name(opts));
 569         refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
 570         if (the_index.cache_changed) {
 571                 if (write_index(&the_index, index_fd) ||
 572                     commit_locked_index(&index_lock))
 573                         die(_("git %s: failed to refresh the index"), action_name(opts));
 574         }
 575         rollback_lock_file(&index_lock);
 576 }
 577
 578 static int format_todo(struct strbuf *buf, struct commit_list *todo_list,
 579                 struct replay_opts *opts)
 580 {
 581         struct commit_list *cur = NULL;
 582         const char *sha1_abbrev = NULL;
 583         const char *action_str = opts->action == REPLAY_REVERT ? "revert" : "pick";
 584         const char *subject;
 585         int subject_len;
 586
 587         for (cur = todo_list; cur; cur = cur->next) {
 588                 sha1_abbrev = find_unique_abbrev(cur->item->object.sha1, DEFAULT_ABBREV);
 589                 subject_len = find_commit_subject(cur->item->buffer, &subject);
 590                 strbuf_addf(buf, "%s %s %.*s\n", action_str, sha1_abbrev,
 591                         subject_len, subject);
 592         }
 593         return 0;
 594 }
 595
 596 static struct commit *parse_insn_line(char *bol, char *eol, struct replay_opts *opts)
 597 {
 598         unsigned char commit_sha1[20];
 599         enum replay_action action;
 600         char *end_of_object_name;
 601         int saved, status, padding;
 602
 603         if (!prefixcmp(bol, "pick")) {
 604                 action = REPLAY_PICK;
 605                 bol += strlen("pick");
 606         } else if (!prefixcmp(bol, "revert")) {
 607                 action = REPLAY_REVERT;
 608                 bol += strlen("revert");
 609         } else
 610                 return NULL;
 611
 612         /* Eat up extra spaces/ tabs before object name */
 613         padding = strspn(bol, " \t");
 614         if (!padding)
 615                 return NULL;
 616         bol += padding;
 617
 618         end_of_object_name = bol + strcspn(bol, " \t\n");
 619         saved = *end_of_object_name;
 620         *end_of_object_name = '\0';
 621         status = get_sha1(bol, commit_sha1);
 622         *end_of_object_name = saved;
 623
 624         /*
 625          * Verify that the action matches up with the one in
 626          * opts; we don't support arbitrary instructions
 627          */
 628         if (action != opts->action) {
 629                 const char *action_str;
 630                 action_str = action == REPLAY_REVERT ? "revert" : "cherry-pick";
 631                 error(_("Cannot %s during a %s"), action_str, action_name(opts));
 632                 return NULL;
 633         }
 634
 635         if (status < 0)
 636                 return NULL;
 637
 638         return lookup_commit_reference(commit_sha1);
 639 }
 640
 641 static int parse_insn_buffer(char *buf, struct commit_list **todo_list,
 642                         struct replay_opts *opts)
 643 {
 644         struct commit_list **next = todo_list;
 645         struct commit *commit;
 646         char *p = buf;
 647         int i;
 648
 649         for (i = 1; *p; i++) {
 650                 char *eol = strchrnul(p, '\n');
 651                 commit = parse_insn_line(p, eol, opts);
 652                 if (!commit)
 653                         return error(_("Could not parse line %d."), i);
 654                 next = commit_list_append(commit, next);
 655                 p = *eol ? eol + 1 : eol;
 656         }
 657         if (!*todo_list)
 658                 return error(_("No commits parsed."));
 659         return 0;
 660 }
 661
 662 static void read_populate_todo(struct commit_list **todo_list,
 663                         struct replay_opts *opts)
 664 {
 665         const char *todo_file = git_path(SEQ_TODO_FILE);
 666         struct strbuf buf = STRBUF_INIT;
 667         int fd, res;
 668
 669         fd = open(todo_file, O_RDONLY);
 670         if (fd < 0)
 671                 die_errno(_("Could not open %s"), todo_file);
 672         if (strbuf_read(&buf, fd, 0) < 0) {
 673                 close(fd);
 674                 strbuf_release(&buf);
 675                 die(_("Could not read %s."), todo_file);
 676         }
 677         close(fd);
 678
 679         res = parse_insn_buffer(buf.buf, todo_list, opts);
 680         strbuf_release(&buf);
 681         if (res)
 682                 die(_("Unusable instruction sheet: %s"), todo_file);
 683 }
 684
 685 static int populate_opts_cb(const char *key, const char *value, void *data)
 686 {
 687         struct replay_opts *opts = data;
 688         int error_flag = 1;
 689
 690         if (!value)
 691                 error_flag = 0;
 692         else if (!strcmp(key, "options.no-commit"))
 693                 opts->no_commit = git_config_bool_or_int(key, value, &error_flag);
 694         else if (!strcmp(key, "options.edit"))
 695                 opts->edit = git_config_bool_or_int(key, value, &error_flag);
 696         else if (!strcmp(key, "options.signoff"))
 697                 opts->signoff = git_config_bool_or_int(key, value, &error_flag);
 698         else if (!strcmp(key, "options.record-origin"))
 699                 opts->record_origin = git_config_bool_or_int(key, value, &error_flag);
 700         else if (!strcmp(key, "options.allow-ff"))
 701                 opts->allow_ff = git_config_bool_or_int(key, value, &error_flag);
 702         else if (!strcmp(key, "options.mainline"))
 703                 opts->mainline = git_config_int(key, value);
 704         else if (!strcmp(key, "options.strategy"))
 705                 git_config_string(&opts->strategy, key, value);
 706         else if (!strcmp(key, "options.strategy-option")) {
 707                 ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
 708                 opts->xopts[opts->xopts_nr++] = xstrdup(value);
 709         } else
 710                 return error(_("Invalid key: %s"), key);
 711
 712         if (!error_flag)
 713                 return error(_("Invalid value for %s: %s"), key, value);
 714
 715         return 0;
 716 }
 717
 718 static void read_populate_opts(struct replay_opts **opts_ptr)
 719 {
 720         const char *opts_file = git_path(SEQ_OPTS_FILE);
 721
 722         if (!file_exists(opts_file))
 723                 return;
 724         if (git_config_from_file(populate_opts_cb, opts_file, *opts_ptr) < 0)
 725                 die(_("Malformed options sheet: %s"), opts_file);
 726 }
 727
 728 static void walk_revs_populate_todo(struct commit_list **todo_list,
 729                                 struct replay_opts *opts)
 730 {
 731         struct commit *commit;
 732         struct commit_list **next;
 733
 734         prepare_revs(opts);
 735
 736         next = todo_list;
 737         while ((commit = get_revision(opts->revs)))
 738                 next = commit_list_append(commit, next);
 739 }
 740
 741 static int create_seq_dir(void)
 742 {
 743         const char *seq_dir = git_path(SEQ_DIR);
 744
 745         if (file_exists(seq_dir)) {
 746                 error(_("a cherry-pick or revert is already in progress"));
 747                 advise(_("try \"git cherry-pick (--continue | --quit | --abort)\""));
 748                 return -1;
 749         }
 750         else if (mkdir(seq_dir, 0777) < 0)
 751                 die_errno(_("Could not create sequencer directory %s"), seq_dir);
 752         return 0;
 753 }
 754
 755 static void save_head(const char *head)
 756 {
 757         const char *head_file = git_path(SEQ_HEAD_FILE);
 758         static struct lock_file head_lock;
 759         struct strbuf buf = STRBUF_INIT;
 760         int fd;
 761
 762         fd = hold_lock_file_for_update(&head_lock, head_file, LOCK_DIE_ON_ERROR);
 763         strbuf_addf(&buf, "%s\n", head);
 764         if (write_in_full(fd, buf.buf, buf.len) < 0)
 765                 die_errno(_("Could not write to %s"), head_file);
 766         if (commit_lock_file(&head_lock) < 0)
 767                 die(_("Error wrapping up %s."), head_file);
 768 }
 769
 770 static int reset_for_rollback(const unsigned char *sha1)
 771 {
 772         const char *argv[4];    /* reset --merge <arg> + NULL */
 773         argv[0] = "reset";
 774         argv[1] = "--merge";
 775         argv[2] = sha1_to_hex(sha1);
 776         argv[3] = NULL;
 777         return run_command_v_opt(argv, RUN_GIT_CMD);
 778 }
 779
 780 static int rollback_single_pick(void)
 781 {
 782         unsigned char head_sha1[20];
 783
 784         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
 785             !file_exists(git_path("REVERT_HEAD")))
 786                 return error(_("no cherry-pick or revert in progress"));
 787         if (read_ref_full("HEAD", head_sha1, 0, NULL))
 788                 return error(_("cannot resolve HEAD"));
 789         if (is_null_sha1(head_sha1))
 790                 return error(_("cannot abort from a branch yet to be born"));
 791         return reset_for_rollback(head_sha1);
 792 }
 793
 794 static int sequencer_rollback(struct replay_opts *opts)
 795 {
 796         const char *filename;
 797         FILE *f;
 798         unsigned char sha1[20];
 799         struct strbuf buf = STRBUF_INIT;
 800
 801         filename = git_path(SEQ_HEAD_FILE);
 802         f = fopen(filename, "r");
 803         if (!f && errno == ENOENT) {
 804                 /*
 805                  * There is no multiple-cherry-pick in progress.
 806                  * If CHERRY_PICK_HEAD or REVERT_HEAD indicates
 807                  * a single-cherry-pick in progress, abort that.
 808                  */
 809                 return rollback_single_pick();
 810         }
 811         if (!f)
 812                 return error(_("cannot open %s: %s"), filename,
 813                                                 strerror(errno));
 814         if (strbuf_getline(&buf, f, '\n')) {
 815                 error(_("cannot read %s: %s"), filename, ferror(f) ?
 816                         strerror(errno) : _("unexpected end of file"));
 817                 fclose(f);
 818                 goto fail;
 819         }
 820         fclose(f);
 821         if (get_sha1_hex(buf.buf, sha1) || buf.buf[40] != '\0') {
 822                 error(_("stored pre-cherry-pick HEAD file '%s' is corrupt"),
 823                         filename);
 824                 goto fail;
 825         }
 826         if (reset_for_rollback(sha1))
 827                 goto fail;
 828         remove_sequencer_state();
 829         strbuf_release(&buf);
 830         return 0;
 831 fail:
 832         strbuf_release(&buf);
 833         return -1;
 834 }
 835
 836 static void save_todo(struct commit_list *todo_list, struct replay_opts *opts)
 837 {
 838         const char *todo_file = git_path(SEQ_TODO_FILE);
 839         static struct lock_file todo_lock;
 840         struct strbuf buf = STRBUF_INIT;
 841         int fd;
 842
 843         fd = hold_lock_file_for_update(&todo_lock, todo_file, LOCK_DIE_ON_ERROR);
 844         if (format_todo(&buf, todo_list, opts) < 0)
 845                 die(_("Could not format %s."), todo_file);
 846         if (write_in_full(fd, buf.buf, buf.len) < 0) {
 847                 strbuf_release(&buf);
 848                 die_errno(_("Could not write to %s"), todo_file);
 849         }
 850         if (commit_lock_file(&todo_lock) < 0) {
 851                 strbuf_release(&buf);
 852                 die(_("Error wrapping up %s."), todo_file);
 853         }
 854         strbuf_release(&buf);
 855 }
 856
 857 static void save_opts(struct replay_opts *opts)
 858 {
 859         const char *opts_file = git_path(SEQ_OPTS_FILE);
 860
 861         if (opts->no_commit)
 862                 git_config_set_in_file(opts_file, "options.no-commit", "true");
 863         if (opts->edit)
 864                 git_config_set_in_file(opts_file, "options.edit", "true");
 865         if (opts->signoff)
 866                 git_config_set_in_file(opts_file, "options.signoff", "true");
 867         if (opts->record_origin)
 868                 git_config_set_in_file(opts_file, "options.record-origin", "true");
 869         if (opts->allow_ff)
 870                 git_config_set_in_file(opts_file, "options.allow-ff", "true");
 871         if (opts->mainline) {
 872                 struct strbuf buf = STRBUF_INIT;
 873                 strbuf_addf(&buf, "%d", opts->mainline);
 874                 git_config_set_in_file(opts_file, "options.mainline", buf.buf);
 875                 strbuf_release(&buf);
 876         }
 877         if (opts->strategy)
 878                 git_config_set_in_file(opts_file, "options.strategy", opts->strategy);
 879         if (opts->xopts) {
 880                 int i;
 881                 for (i = 0; i < opts->xopts_nr; i++)
 882                         git_config_set_multivar_in_file(opts_file,
 883                                                         "options.strategy-option",
 884                                                         opts->xopts[i], "^$", 0);
 885         }
 886 }
 887
 888 static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
 889 {
 890         struct commit_list *cur;
 891         int res;
 892
 893         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
 894         if (opts->allow_ff)
 895                 assert(!(opts->signoff || opts->no_commit ||
 896                                 opts->record_origin || opts->edit));
 897         read_and_refresh_cache(opts);
 898
 899         for (cur = todo_list; cur; cur = cur->next) {
 900                 save_todo(cur, opts);
 901                 res = do_pick_commit(cur->item, opts);
 902                 if (res)
 903                         return res;
 904         }
 905
 906         /*
 907          * Sequence of picks finished successfully; cleanup by
 908          * removing the .git/sequencer directory
 909          */
 910         remove_sequencer_state();
 911         return 0;
 912 }
 913
 914 static int continue_single_pick(void)
 915 {
 916         const char *argv[] = { "commit", NULL };
 917
 918         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
 919             !file_exists(git_path("REVERT_HEAD")))
 920                 return error(_("no cherry-pick or revert in progress"));
 921         return run_command_v_opt(argv, RUN_GIT_CMD);
 922 }
 923
 924 static int sequencer_continue(struct replay_opts *opts)
 925 {
 926         struct commit_list *todo_list = NULL;
 927
 928         if (!file_exists(git_path(SEQ_TODO_FILE)))
 929                 return continue_single_pick();
 930         read_populate_opts(&opts);
 931         read_populate_todo(&todo_list, opts);
 932
 933         /* Verify that the conflict has been resolved */
 934         if (file_exists(git_path("CHERRY_PICK_HEAD")) ||
 935             file_exists(git_path("REVERT_HEAD"))) {
 936                 int ret = continue_single_pick();
 937                 if (ret)
 938                         return ret;
 939         }
 940         if (index_differs_from("HEAD", 0))
 941                 return error_dirty_index(opts);
 942         todo_list = todo_list->next;
 943         return pick_commits(todo_list, opts);
 944 }
 945
 946 static int single_pick(struct commit *cmit, struct replay_opts *opts)
 947 {
 948         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
 949         return do_pick_commit(cmit, opts);
 950 }
 951
 952 int sequencer_pick_revisions(struct replay_opts *opts)
 953 {
 954         struct commit_list *todo_list = NULL;
 955         unsigned char sha1[20];
 956
 957         if (opts->subcommand == REPLAY_NONE)
 958                 assert(opts->revs);
 959
 960         read_and_refresh_cache(opts);
 961
 962         /*
 963          * Decide what to do depending on the arguments; a fresh
 964          * cherry-pick should be handled differently from an existing
 965          * one that is being continued
 966          */
 967         if (opts->subcommand == REPLAY_REMOVE_STATE) {
 968                 remove_sequencer_state();
 969                 return 0;
 970         }
 971         if (opts->subcommand == REPLAY_ROLLBACK)
 972                 return sequencer_rollback(opts);
 973         if (opts->subcommand == REPLAY_CONTINUE)
 974                 return sequencer_continue(opts);
 975
 976         /*
 977          * If we were called as "git cherry-pick <commit>", just
 978          * cherry-pick/revert it, set CHERRY_PICK_HEAD /
 979          * REVERT_HEAD, and don't touch the sequencer state.
 980          * This means it is possible to cherry-pick in the middle
 981          * of a cherry-pick sequence.
 982          */
 983         if (opts->revs->cmdline.nr == 1 &&
 984             opts->revs->cmdline.rev->whence == REV_CMD_REV &&
 985             opts->revs->no_walk &&
 986             !opts->revs->cmdline.rev->flags) {
 987                 struct commit *cmit;
 988                 if (prepare_revision_walk(opts->revs))
 989                         die(_("revision walk setup failed"));
 990                 cmit = get_revision(opts->revs);
 991                 if (!cmit || get_revision(opts->revs))
 992                         die("BUG: expected exactly one commit from walk");
 993                 return single_pick(cmit, opts);
 994         }
 995
 996         /*
 997          * Start a new cherry-pick/ revert sequence; but
 998          * first, make sure that an existing one isn't in
 999          * progress
1000          */
1001
1002         walk_revs_populate_todo(&todo_list, opts);
1003         if (create_seq_dir() < 0)
1004                 return -1;
1005         if (get_sha1("HEAD", sha1)) {
1006                 if (opts->action == REPLAY_REVERT)
1007                         return error(_("Can't revert as initial commit"));
1008                 return error(_("Can't cherry-pick into empty head"));
1009         }
1010         save_head(sha1_to_hex(sha1));
1011         save_opts(opts);
1012         return pick_commits(todo_list, opts);
1013 }