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

   1 #include "cache.h"
   2 #include "sequencer.h"
   3 #include "dir.h"
   4 #include "object.h"
   5 #include "commit.h"
   6 #include "tag.h"
   7 #include "run-command.h"
   8 #include "exec_cmd.h"
   9 #include "utf8.h"
  10 #include "cache-tree.h"
  11 #include "diff.h"
  12 #include "revision.h"
  13 #include "rerere.h"
  14 #include "merge-recursive.h"
  15 #include "refs.h"
  16 #include "argv-array.h"
  17
  18 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
  19
  20 const char sign_off_header[] = "Signed-off-by: ";
  21 static const char cherry_picked_prefix[] = "(cherry picked from commit ";
  22
  23 static int is_rfc2822_line(const char *buf, int len)
  24 {
  25         int i;
  26
  27         for (i = 0; i < len; i++) {
  28                 int ch = buf[i];
  29                 if (ch == ':')
  30                         return 1;
  31                 if (!isalnum(ch) && ch != '-')
  32                         break;
  33         }
  34
  35         return 0;
  36 }
  37
  38 static int is_cherry_picked_from_line(const char *buf, int len)
  39 {
  40         /*
  41          * We only care that it looks roughly like (cherry picked from ...)
  42          */
  43         return len > strlen(cherry_picked_prefix) + 1 &&
  44                 starts_with(buf, cherry_picked_prefix) && buf[len - 1] == ')';
  45 }
  46
  47 /*
  48  * Returns 0 for non-conforming footer
  49  * Returns 1 for conforming footer
  50  * Returns 2 when sob exists within conforming footer
  51  * Returns 3 when sob exists within conforming footer as last entry
  52  */
  53 static int has_conforming_footer(struct strbuf *sb, struct strbuf *sob,
  54         int ignore_footer)
  55 {
  56         char prev;
  57         int i, k;
  58         int len = sb->len - ignore_footer;
  59         const char *buf = sb->buf;
  60         int found_sob = 0;
  61
  62         /* footer must end with newline */
  63         if (!len || buf[len - 1] != '\n')
  64                 return 0;
  65
  66         prev = '\0';
  67         for (i = len - 1; i > 0; i--) {
  68                 char ch = buf[i];
  69                 if (prev == '\n' && ch == '\n') /* paragraph break */
  70                         break;
  71                 prev = ch;
  72         }
  73
  74         /* require at least one blank line */
  75         if (prev != '\n' || buf[i] != '\n')
  76                 return 0;
  77
  78         /* advance to start of last paragraph */
  79         while (i < len - 1 && buf[i] == '\n')
  80                 i++;
  81
  82         for (; i < len; i = k) {
  83                 int found_rfc2822;
  84
  85                 for (k = i; k < len && buf[k] != '\n'; k++)
  86                         ; /* do nothing */
  87                 k++;
  88
  89                 found_rfc2822 = is_rfc2822_line(buf + i, k - i - 1);
  90                 if (found_rfc2822 && sob &&
  91                     !strncmp(buf + i, sob->buf, sob->len))
  92                         found_sob = k;
  93
  94                 if (!(found_rfc2822 ||
  95                       is_cherry_picked_from_line(buf + i, k - i - 1)))
  96                         return 0;
  97         }
  98         if (found_sob == i)
  99                 return 3;
 100         if (found_sob)
 101                 return 2;
 102         return 1;
 103 }
 104
 105 static void remove_sequencer_state(void)
 106 {
 107         struct strbuf seq_dir = STRBUF_INIT;
 108
 109         strbuf_addf(&seq_dir, "%s", git_path(SEQ_DIR));
 110         remove_dir_recursively(&seq_dir, 0);
 111         strbuf_release(&seq_dir);
 112 }
 113
 114 static const char *action_name(const struct replay_opts *opts)
 115 {
 116         return opts->action == REPLAY_REVERT ? "revert" : "cherry-pick";
 117 }
 118
 119 struct commit_message {
 120         char *parent_label;
 121         const char *label;
 122         const char *subject;
 123         const char *message;
 124 };
 125
 126 static int get_message(struct commit *commit, struct commit_message *out)
 127 {
 128         const char *abbrev, *subject;
 129         int abbrev_len, subject_len;
 130         char *q;
 131
 132         if (!git_commit_encoding)
 133                 git_commit_encoding = "UTF-8";
 134
 135         out->message = logmsg_reencode(commit, NULL, git_commit_encoding);
 136         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
 137         abbrev_len = strlen(abbrev);
 138
 139         subject_len = find_commit_subject(out->message, &subject);
 140
 141         out->parent_label = xmalloc(strlen("parent of ") + abbrev_len +
 142                               strlen("... ") + subject_len + 1);
 143         q = out->parent_label;
 144         q = mempcpy(q, "parent of ", strlen("parent of "));
 145         out->label = q;
 146         q = mempcpy(q, abbrev, abbrev_len);
 147         q = mempcpy(q, "... ", strlen("... "));
 148         out->subject = q;
 149         q = mempcpy(q, subject, subject_len);
 150         *q = '\0';
 151         return 0;
 152 }
 153
 154 static void free_message(struct commit *commit, struct commit_message *msg)
 155 {
 156         free(msg->parent_label);
 157         unuse_commit_buffer(commit, msg->message);
 158 }
 159
 160 static void write_cherry_pick_head(struct commit *commit, const char *pseudoref)
 161 {
 162         const char *filename;
 163         int fd;
 164         struct strbuf buf = STRBUF_INIT;
 165
 166         strbuf_addf(&buf, "%s\n", sha1_to_hex(commit->object.sha1));
 167
 168         filename = git_path("%s", pseudoref);
 169         fd = open(filename, O_WRONLY | O_CREAT, 0666);
 170         if (fd < 0)
 171                 die_errno(_("Could not open '%s' for writing"), filename);
 172         if (write_in_full(fd, buf.buf, buf.len) != buf.len || close(fd))
 173                 die_errno(_("Could not write to '%s'"), filename);
 174         strbuf_release(&buf);
 175 }
 176
 177 static void print_advice(int show_hint, struct replay_opts *opts)
 178 {
 179         char *msg = getenv("GIT_CHERRY_PICK_HELP");
 180
 181         if (msg) {
 182                 fprintf(stderr, "%s\n", msg);
 183                 /*
 184                  * A conflict has occurred but the porcelain
 185                  * (typically rebase --interactive) wants to take care
 186                  * of the commit itself so remove CHERRY_PICK_HEAD
 187                  */
 188                 unlink(git_path("CHERRY_PICK_HEAD"));
 189                 return;
 190         }
 191
 192         if (show_hint) {
 193                 if (opts->no_commit)
 194                         advise(_("after resolving the conflicts, mark the corrected paths\n"
 195                                  "with 'git add <paths>' or 'git rm <paths>'"));
 196                 else
 197                         advise(_("after resolving the conflicts, mark the corrected paths\n"
 198                                  "with 'git add <paths>' or 'git rm <paths>'\n"
 199                                  "and commit the result with 'git commit'"));
 200         }
 201 }
 202
 203 static void write_message(struct strbuf *msgbuf, const char *filename)
 204 {
 205         static struct lock_file msg_file;
 206
 207         int msg_fd = hold_lock_file_for_update(&msg_file, filename,
 208                                                LOCK_DIE_ON_ERROR);
 209         if (write_in_full(msg_fd, msgbuf->buf, msgbuf->len) < 0)
 210                 die_errno(_("Could not write to %s"), filename);
 211         strbuf_release(msgbuf);
 212         if (commit_lock_file(&msg_file) < 0)
 213                 die(_("Error wrapping up %s"), filename);
 214 }
 215
 216 static struct tree *empty_tree(void)
 217 {
 218         return lookup_tree(EMPTY_TREE_SHA1_BIN);
 219 }
 220
 221 static int error_dirty_index(struct replay_opts *opts)
 222 {
 223         if (read_cache_unmerged())
 224                 return error_resolve_conflict(action_name(opts));
 225
 226         /* Different translation strings for cherry-pick and revert */
 227         if (opts->action == REPLAY_PICK)
 228                 error(_("Your local changes would be overwritten by cherry-pick."));
 229         else
 230                 error(_("Your local changes would be overwritten by revert."));
 231
 232         if (advice_commit_before_merge)
 233                 advise(_("Commit your changes or stash them to proceed."));
 234         return -1;
 235 }
 236
 237 static int fast_forward_to(const unsigned char *to, const unsigned char *from,
 238                         int unborn, struct replay_opts *opts)
 239 {
 240         struct ref_lock *ref_lock;
 241         struct strbuf sb = STRBUF_INIT;
 242         int ret;
 243
 244         read_cache();
 245         if (checkout_fast_forward(from, to, 1))
 246                 exit(128); /* the callee should have complained already */
 247         ref_lock = lock_any_ref_for_update("HEAD", unborn ? null_sha1 : from,
 248                                            0, NULL);
 249         if (!ref_lock)
 250                 return error(_("Failed to lock HEAD during fast_forward_to"));
 251
 252         strbuf_addf(&sb, "%s: fast-forward", action_name(opts));
 253         ret = write_ref_sha1(ref_lock, to, sb.buf);
 254
 255         strbuf_release(&sb);
 256         return ret;
 257 }
 258
 259 static int do_recursive_merge(struct commit *base, struct commit *next,
 260                               const char *base_label, const char *next_label,
 261                               unsigned char *head, struct strbuf *msgbuf,
 262                               struct replay_opts *opts)
 263 {
 264         struct merge_options o;
 265         struct tree *result, *next_tree, *base_tree, *head_tree;
 266         int clean, index_fd;
 267         const char **xopt;
 268         static struct lock_file index_lock;
 269
 270         index_fd = hold_locked_index(&index_lock, 1);
 271
 272         read_cache();
 273
 274         init_merge_options(&o);
 275         o.ancestor = base ? base_label : "(empty tree)";
 276         o.branch1 = "HEAD";
 277         o.branch2 = next ? next_label : "(empty tree)";
 278
 279         head_tree = parse_tree_indirect(head);
 280         next_tree = next ? next->tree : empty_tree();
 281         base_tree = base ? base->tree : empty_tree();
 282
 283         for (xopt = opts->xopts; xopt != opts->xopts + opts->xopts_nr; xopt++)
 284                 parse_merge_opt(&o, *xopt);
 285
 286         clean = merge_trees(&o,
 287                             head_tree,
 288                             next_tree, base_tree, &result);
 289
 290         if (active_cache_changed &&
 291             (write_cache(index_fd, active_cache, active_nr) ||
 292              commit_locked_index(&index_lock)))
 293                 /* TRANSLATORS: %s will be "revert" or "cherry-pick" */
 294                 die(_("%s: Unable to write new index file"), action_name(opts));
 295         rollback_lock_file(&index_lock);
 296
 297         if (opts->signoff)
 298                 append_signoff(msgbuf, 0, 0);
 299
 300         if (!clean) {
 301                 int i;
 302                 strbuf_addstr(msgbuf, "\nConflicts:\n");
 303                 for (i = 0; i < active_nr;) {
 304                         const struct cache_entry *ce = active_cache[i++];
 305                         if (ce_stage(ce)) {
 306                                 strbuf_addch(msgbuf, '\t');
 307                                 strbuf_addstr(msgbuf, ce->name);
 308                                 strbuf_addch(msgbuf, '\n');
 309                                 while (i < active_nr && !strcmp(ce->name,
 310                                                 active_cache[i]->name))
 311                                         i++;
 312                         }
 313                 }
 314         }
 315
 316         return !clean;
 317 }
 318
 319 static int is_index_unchanged(void)
 320 {
 321         unsigned char head_sha1[20];
 322         struct commit *head_commit;
 323
 324         if (!resolve_ref_unsafe("HEAD", head_sha1, 1, NULL))
 325                 return error(_("Could not resolve HEAD commit\n"));
 326
 327         head_commit = lookup_commit(head_sha1);
 328
 329         /*
 330          * If head_commit is NULL, check_commit, called from
 331          * lookup_commit, would have indicated that head_commit is not
 332          * a commit object already.  parse_commit() will return failure
 333          * without further complaints in such a case.  Otherwise, if
 334          * the commit is invalid, parse_commit() will complain.  So
 335          * there is nothing for us to say here.  Just return failure.
 336          */
 337         if (parse_commit(head_commit))
 338                 return -1;
 339
 340         if (!active_cache_tree)
 341                 active_cache_tree = cache_tree();
 342
 343         if (!cache_tree_fully_valid(active_cache_tree))
 344                 if (cache_tree_update(active_cache_tree,
 345                                       (const struct cache_entry * const *)active_cache,
 346                                       active_nr, 0))
 347                         return error(_("Unable to update cache tree\n"));
 348
 349         return !hashcmp(active_cache_tree->sha1, head_commit->tree->object.sha1);
 350 }
 351
 352 /*
 353  * If we are cherry-pick, and if the merge did not result in
 354  * hand-editing, we will hit this commit and inherit the original
 355  * author date and name.
 356  * If we are revert, or if our cherry-pick results in a hand merge,
 357  * we had better say that the current user is responsible for that.
 358  */
 359 static int run_git_commit(const char *defmsg, struct replay_opts *opts,
 360                           int allow_empty)
 361 {
 362         struct argv_array array;
 363         int rc;
 364
 365         argv_array_init(&array);
 366         argv_array_push(&array, "commit");
 367         argv_array_push(&array, "-n");
 368
 369         if (opts->gpg_sign)
 370                 argv_array_pushf(&array, "-S%s", opts->gpg_sign);
 371         if (opts->signoff)
 372                 argv_array_push(&array, "-s");
 373         if (!opts->edit) {
 374                 argv_array_push(&array, "-F");
 375                 argv_array_push(&array, defmsg);
 376         }
 377
 378         if (allow_empty)
 379                 argv_array_push(&array, "--allow-empty");
 380
 381         if (opts->allow_empty_message)
 382                 argv_array_push(&array, "--allow-empty-message");
 383
 384         rc = run_command_v_opt(array.argv, RUN_GIT_CMD);
 385         argv_array_clear(&array);
 386         return rc;
 387 }
 388
 389 static int is_original_commit_empty(struct commit *commit)
 390 {
 391         const unsigned char *ptree_sha1;
 392
 393         if (parse_commit(commit))
 394                 return error(_("Could not parse commit %s\n"),
 395                              sha1_to_hex(commit->object.sha1));
 396         if (commit->parents) {
 397                 struct commit *parent = commit->parents->item;
 398                 if (parse_commit(parent))
 399                         return error(_("Could not parse parent commit %s\n"),
 400                                 sha1_to_hex(parent->object.sha1));
 401                 ptree_sha1 = parent->tree->object.sha1;
 402         } else {
 403                 ptree_sha1 = EMPTY_TREE_SHA1_BIN; /* commit is root */
 404         }
 405
 406         return !hashcmp(ptree_sha1, commit->tree->object.sha1);
 407 }
 408
 409 /*
 410  * Do we run "git commit" with "--allow-empty"?
 411  */
 412 static int allow_empty(struct replay_opts *opts, struct commit *commit)
 413 {
 414         int index_unchanged, empty_commit;
 415
 416         /*
 417          * Three cases:
 418          *
 419          * (1) we do not allow empty at all and error out.
 420          *
 421          * (2) we allow ones that were initially empty, but
 422          * forbid the ones that become empty;
 423          *
 424          * (3) we allow both.
 425          */
 426         if (!opts->allow_empty)
 427                 return 0; /* let "git commit" barf as necessary */
 428
 429         index_unchanged = is_index_unchanged();
 430         if (index_unchanged < 0)
 431                 return index_unchanged;
 432         if (!index_unchanged)
 433                 return 0; /* we do not have to say --allow-empty */
 434
 435         if (opts->keep_redundant_commits)
 436                 return 1;
 437
 438         empty_commit = is_original_commit_empty(commit);
 439         if (empty_commit < 0)
 440                 return empty_commit;
 441         if (!empty_commit)
 442                 return 0;
 443         else
 444                 return 1;
 445 }
 446
 447 static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
 448 {
 449         unsigned char head[20];
 450         struct commit *base, *next, *parent;
 451         const char *base_label, *next_label;
 452         struct commit_message msg = { NULL, NULL, NULL, NULL };
 453         char *defmsg = NULL;
 454         struct strbuf msgbuf = STRBUF_INIT;
 455         int res, unborn = 0, allow;
 456
 457         if (opts->no_commit) {
 458                 /*
 459                  * We do not intend to commit immediately.  We just want to
 460                  * merge the differences in, so let's compute the tree
 461                  * that represents the "current" state for merge-recursive
 462                  * to work on.
 463                  */
 464                 if (write_cache_as_tree(head, 0, NULL))
 465                         die (_("Your index file is unmerged."));
 466         } else {
 467                 unborn = get_sha1("HEAD", head);
 468                 if (unborn)
 469                         hashcpy(head, EMPTY_TREE_SHA1_BIN);
 470                 if (index_differs_from(unborn ? EMPTY_TREE_SHA1_HEX : "HEAD", 0))
 471                         return error_dirty_index(opts);
 472         }
 473         discard_cache();
 474
 475         if (!commit->parents) {
 476                 parent = NULL;
 477         }
 478         else if (commit->parents->next) {
 479                 /* Reverting or cherry-picking a merge commit */
 480                 int cnt;
 481                 struct commit_list *p;
 482
 483                 if (!opts->mainline)
 484                         return error(_("Commit %s is a merge but no -m option was given."),
 485                                 sha1_to_hex(commit->object.sha1));
 486
 487                 for (cnt = 1, p = commit->parents;
 488                      cnt != opts->mainline && p;
 489                      cnt++)
 490                         p = p->next;
 491                 if (cnt != opts->mainline || !p)
 492                         return error(_("Commit %s does not have parent %d"),
 493                                 sha1_to_hex(commit->object.sha1), opts->mainline);
 494                 parent = p->item;
 495         } else if (0 < opts->mainline)
 496                 return error(_("Mainline was specified but commit %s is not a merge."),
 497                         sha1_to_hex(commit->object.sha1));
 498         else
 499                 parent = commit->parents->item;
 500
 501         if (opts->allow_ff &&
 502             ((parent && !hashcmp(parent->object.sha1, head)) ||
 503              (!parent && unborn)))
 504                 return fast_forward_to(commit->object.sha1, head, unborn, opts);
 505
 506         if (parent && parse_commit(parent) < 0)
 507                 /* TRANSLATORS: The first %s will be "revert" or
 508                    "cherry-pick", the second %s a SHA1 */
 509                 return error(_("%s: cannot parse parent commit %s"),
 510                         action_name(opts), sha1_to_hex(parent->object.sha1));
 511
 512         if (get_message(commit, &msg) != 0)
 513                 return error(_("Cannot get commit message for %s"),
 514                         sha1_to_hex(commit->object.sha1));
 515
 516         /*
 517          * "commit" is an existing commit.  We would want to apply
 518          * the difference it introduces since its first parent "prev"
 519          * on top of the current HEAD if we are cherry-pick.  Or the
 520          * reverse of it if we are revert.
 521          */
 522
 523         defmsg = git_pathdup("MERGE_MSG");
 524
 525         if (opts->action == REPLAY_REVERT) {
 526                 base = commit;
 527                 base_label = msg.label;
 528                 next = parent;
 529                 next_label = msg.parent_label;
 530                 strbuf_addstr(&msgbuf, "Revert \"");
 531                 strbuf_addstr(&msgbuf, msg.subject);
 532                 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
 533                 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 534
 535                 if (commit->parents && commit->parents->next) {
 536                         strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
 537                         strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
 538                 }
 539                 strbuf_addstr(&msgbuf, ".\n");
 540         } else {
 541                 const char *p;
 542
 543                 base = parent;
 544                 base_label = msg.parent_label;
 545                 next = commit;
 546                 next_label = msg.label;
 547
 548                 /*
 549                  * Append the commit log message to msgbuf; it starts
 550                  * after the tree, parent, author, committer
 551                  * information followed by "\n\n".
 552                  */
 553                 p = strstr(msg.message, "\n\n");
 554                 if (p) {
 555                         p += 2;
 556                         strbuf_addstr(&msgbuf, p);
 557                 }
 558
 559                 if (opts->record_origin) {
 560                         if (!has_conforming_footer(&msgbuf, NULL, 0))
 561                                 strbuf_addch(&msgbuf, '\n');
 562                         strbuf_addstr(&msgbuf, cherry_picked_prefix);
 563                         strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 564                         strbuf_addstr(&msgbuf, ")\n");
 565                 }
 566         }
 567
 568         if (!opts->strategy || !strcmp(opts->strategy, "recursive") || opts->action == REPLAY_REVERT) {
 569                 res = do_recursive_merge(base, next, base_label, next_label,
 570                                          head, &msgbuf, opts);
 571                 write_message(&msgbuf, defmsg);
 572         } else {
 573                 struct commit_list *common = NULL;
 574                 struct commit_list *remotes = NULL;
 575
 576                 write_message(&msgbuf, defmsg);
 577
 578                 commit_list_insert(base, &common);
 579                 commit_list_insert(next, &remotes);
 580                 res = try_merge_command(opts->strategy, opts->xopts_nr, opts->xopts,
 581                                         common, sha1_to_hex(head), remotes);
 582                 free_commit_list(common);
 583                 free_commit_list(remotes);
 584         }
 585
 586         /*
 587          * If the merge was clean or if it failed due to conflict, we write
 588          * CHERRY_PICK_HEAD for the subsequent invocation of commit to use.
 589          * However, if the merge did not even start, then we don't want to
 590          * write it at all.
 591          */
 592         if (opts->action == REPLAY_PICK && !opts->no_commit && (res == 0 || res == 1))
 593                 write_cherry_pick_head(commit, "CHERRY_PICK_HEAD");
 594         if (opts->action == REPLAY_REVERT && ((opts->no_commit && res == 0) || res == 1))
 595                 write_cherry_pick_head(commit, "REVERT_HEAD");
 596
 597         if (res) {
 598                 error(opts->action == REPLAY_REVERT
 599                       ? _("could not revert %s... %s")
 600                       : _("could not apply %s... %s"),
 601                       find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV),
 602                       msg.subject);
 603                 print_advice(res == 1, opts);
 604                 rerere(opts->allow_rerere_auto);
 605                 goto leave;
 606         }
 607
 608         allow = allow_empty(opts, commit);
 609         if (allow < 0) {
 610                 res = allow;
 611                 goto leave;
 612         }
 613         if (!opts->no_commit)
 614                 res = run_git_commit(defmsg, opts, allow);
 615
 616 leave:
 617         free_message(commit, &msg);
 618         free(defmsg);
 619
 620         return res;
 621 }
 622
 623 static void prepare_revs(struct replay_opts *opts)
 624 {
 625         /*
 626          * picking (but not reverting) ranges (but not individual revisions)
 627          * should be done in reverse
 628          */
 629         if (opts->action == REPLAY_PICK && !opts->revs->no_walk)
 630                 opts->revs->reverse ^= 1;
 631
 632         if (prepare_revision_walk(opts->revs))
 633                 die(_("revision walk setup failed"));
 634
 635         if (!opts->revs->commits)
 636                 die(_("empty commit set passed"));
 637 }
 638
 639 static void read_and_refresh_cache(struct replay_opts *opts)
 640 {
 641         static struct lock_file index_lock;
 642         int index_fd = hold_locked_index(&index_lock, 0);
 643         if (read_index_preload(&the_index, NULL) < 0)
 644                 die(_("git %s: failed to read the index"), action_name(opts));
 645         refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
 646         if (the_index.cache_changed) {
 647                 if (write_index(&the_index, index_fd) ||
 648                     commit_locked_index(&index_lock))
 649                         die(_("git %s: failed to refresh the index"), action_name(opts));
 650         }
 651         rollback_lock_file(&index_lock);
 652 }
 653
 654 static int format_todo(struct strbuf *buf, struct commit_list *todo_list,
 655                 struct replay_opts *opts)
 656 {
 657         struct commit_list *cur = NULL;
 658         const char *sha1_abbrev = NULL;
 659         const char *action_str = opts->action == REPLAY_REVERT ? "revert" : "pick";
 660         const char *subject;
 661         int subject_len;
 662
 663         for (cur = todo_list; cur; cur = cur->next) {
 664                 const char *commit_buffer = get_commit_buffer(cur->item, NULL);
 665                 sha1_abbrev = find_unique_abbrev(cur->item->object.sha1, DEFAULT_ABBREV);
 666                 subject_len = find_commit_subject(commit_buffer, &subject);
 667                 strbuf_addf(buf, "%s %s %.*s\n", action_str, sha1_abbrev,
 668                         subject_len, subject);
 669                 unuse_commit_buffer(cur->item, commit_buffer);
 670         }
 671         return 0;
 672 }
 673
 674 static struct commit *parse_insn_line(char *bol, char *eol, struct replay_opts *opts)
 675 {
 676         unsigned char commit_sha1[20];
 677         enum replay_action action;
 678         char *end_of_object_name;
 679         int saved, status, padding;
 680
 681         if (starts_with(bol, "pick")) {
 682                 action = REPLAY_PICK;
 683                 bol += strlen("pick");
 684         } else if (starts_with(bol, "revert")) {
 685                 action = REPLAY_REVERT;
 686                 bol += strlen("revert");
 687         } else
 688                 return NULL;
 689
 690         /* Eat up extra spaces/ tabs before object name */
 691         padding = strspn(bol, " \t");
 692         if (!padding)
 693                 return NULL;
 694         bol += padding;
 695
 696         end_of_object_name = bol + strcspn(bol, " \t\n");
 697         saved = *end_of_object_name;
 698         *end_of_object_name = '\0';
 699         status = get_sha1(bol, commit_sha1);
 700         *end_of_object_name = saved;
 701
 702         /*
 703          * Verify that the action matches up with the one in
 704          * opts; we don't support arbitrary instructions
 705          */
 706         if (action != opts->action) {
 707                 const char *action_str;
 708                 action_str = action == REPLAY_REVERT ? "revert" : "cherry-pick";
 709                 error(_("Cannot %s during a %s"), action_str, action_name(opts));
 710                 return NULL;
 711         }
 712
 713         if (status < 0)
 714                 return NULL;
 715
 716         return lookup_commit_reference(commit_sha1);
 717 }
 718
 719 static int parse_insn_buffer(char *buf, struct commit_list **todo_list,
 720                         struct replay_opts *opts)
 721 {
 722         struct commit_list **next = todo_list;
 723         struct commit *commit;
 724         char *p = buf;
 725         int i;
 726
 727         for (i = 1; *p; i++) {
 728                 char *eol = strchrnul(p, '\n');
 729                 commit = parse_insn_line(p, eol, opts);
 730                 if (!commit)
 731                         return error(_("Could not parse line %d."), i);
 732                 next = commit_list_append(commit, next);
 733                 p = *eol ? eol + 1 : eol;
 734         }
 735         if (!*todo_list)
 736                 return error(_("No commits parsed."));
 737         return 0;
 738 }
 739
 740 static void read_populate_todo(struct commit_list **todo_list,
 741                         struct replay_opts *opts)
 742 {
 743         const char *todo_file = git_path(SEQ_TODO_FILE);
 744         struct strbuf buf = STRBUF_INIT;
 745         int fd, res;
 746
 747         fd = open(todo_file, O_RDONLY);
 748         if (fd < 0)
 749                 die_errno(_("Could not open %s"), todo_file);
 750         if (strbuf_read(&buf, fd, 0) < 0) {
 751                 close(fd);
 752                 strbuf_release(&buf);
 753                 die(_("Could not read %s."), todo_file);
 754         }
 755         close(fd);
 756
 757         res = parse_insn_buffer(buf.buf, todo_list, opts);
 758         strbuf_release(&buf);
 759         if (res)
 760                 die(_("Unusable instruction sheet: %s"), todo_file);
 761 }
 762
 763 static int populate_opts_cb(const char *key, const char *value, void *data)
 764 {
 765         struct replay_opts *opts = data;
 766         int error_flag = 1;
 767
 768         if (!value)
 769                 error_flag = 0;
 770         else if (!strcmp(key, "options.no-commit"))
 771                 opts->no_commit = git_config_bool_or_int(key, value, &error_flag);
 772         else if (!strcmp(key, "options.edit"))
 773                 opts->edit = git_config_bool_or_int(key, value, &error_flag);
 774         else if (!strcmp(key, "options.signoff"))
 775                 opts->signoff = git_config_bool_or_int(key, value, &error_flag);
 776         else if (!strcmp(key, "options.record-origin"))
 777                 opts->record_origin = git_config_bool_or_int(key, value, &error_flag);
 778         else if (!strcmp(key, "options.allow-ff"))
 779                 opts->allow_ff = git_config_bool_or_int(key, value, &error_flag);
 780         else if (!strcmp(key, "options.mainline"))
 781                 opts->mainline = git_config_int(key, value);
 782         else if (!strcmp(key, "options.strategy"))
 783                 git_config_string(&opts->strategy, key, value);
 784         else if (!strcmp(key, "options.gpg-sign"))
 785                 git_config_string(&opts->gpg_sign, key, value);
 786         else if (!strcmp(key, "options.strategy-option")) {
 787                 ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
 788                 opts->xopts[opts->xopts_nr++] = xstrdup(value);
 789         } else
 790                 return error(_("Invalid key: %s"), key);
 791
 792         if (!error_flag)
 793                 return error(_("Invalid value for %s: %s"), key, value);
 794
 795         return 0;
 796 }
 797
 798 static void read_populate_opts(struct replay_opts **opts_ptr)
 799 {
 800         const char *opts_file = git_path(SEQ_OPTS_FILE);
 801
 802         if (!file_exists(opts_file))
 803                 return;
 804         if (git_config_from_file(populate_opts_cb, opts_file, *opts_ptr) < 0)
 805                 die(_("Malformed options sheet: %s"), opts_file);
 806 }
 807
 808 static void walk_revs_populate_todo(struct commit_list **todo_list,
 809                                 struct replay_opts *opts)
 810 {
 811         struct commit *commit;
 812         struct commit_list **next;
 813
 814         prepare_revs(opts);
 815
 816         next = todo_list;
 817         while ((commit = get_revision(opts->revs)))
 818                 next = commit_list_append(commit, next);
 819 }
 820
 821 static int create_seq_dir(void)
 822 {
 823         const char *seq_dir = git_path(SEQ_DIR);
 824
 825         if (file_exists(seq_dir)) {
 826                 error(_("a cherry-pick or revert is already in progress"));
 827                 advise(_("try \"git cherry-pick (--continue | --quit | --abort)\""));
 828                 return -1;
 829         }
 830         else if (mkdir(seq_dir, 0777) < 0)
 831                 die_errno(_("Could not create sequencer directory %s"), seq_dir);
 832         return 0;
 833 }
 834
 835 static void save_head(const char *head)
 836 {
 837         const char *head_file = git_path(SEQ_HEAD_FILE);
 838         static struct lock_file head_lock;
 839         struct strbuf buf = STRBUF_INIT;
 840         int fd;
 841
 842         fd = hold_lock_file_for_update(&head_lock, head_file, LOCK_DIE_ON_ERROR);
 843         strbuf_addf(&buf, "%s\n", head);
 844         if (write_in_full(fd, buf.buf, buf.len) < 0)
 845                 die_errno(_("Could not write to %s"), head_file);
 846         if (commit_lock_file(&head_lock) < 0)
 847                 die(_("Error wrapping up %s."), head_file);
 848 }
 849
 850 static int reset_for_rollback(const unsigned char *sha1)
 851 {
 852         const char *argv[4];    /* reset --merge <arg> + NULL */
 853         argv[0] = "reset";
 854         argv[1] = "--merge";
 855         argv[2] = sha1_to_hex(sha1);
 856         argv[3] = NULL;
 857         return run_command_v_opt(argv, RUN_GIT_CMD);
 858 }
 859
 860 static int rollback_single_pick(void)
 861 {
 862         unsigned char head_sha1[20];
 863
 864         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
 865             !file_exists(git_path("REVERT_HEAD")))
 866                 return error(_("no cherry-pick or revert in progress"));
 867         if (read_ref_full("HEAD", head_sha1, 0, NULL))
 868                 return error(_("cannot resolve HEAD"));
 869         if (is_null_sha1(head_sha1))
 870                 return error(_("cannot abort from a branch yet to be born"));
 871         return reset_for_rollback(head_sha1);
 872 }
 873
 874 static int sequencer_rollback(struct replay_opts *opts)
 875 {
 876         const char *filename;
 877         FILE *f;
 878         unsigned char sha1[20];
 879         struct strbuf buf = STRBUF_INIT;
 880
 881         filename = git_path(SEQ_HEAD_FILE);
 882         f = fopen(filename, "r");
 883         if (!f && errno == ENOENT) {
 884                 /*
 885                  * There is no multiple-cherry-pick in progress.
 886                  * If CHERRY_PICK_HEAD or REVERT_HEAD indicates
 887                  * a single-cherry-pick in progress, abort that.
 888                  */
 889                 return rollback_single_pick();
 890         }
 891         if (!f)
 892                 return error(_("cannot open %s: %s"), filename,
 893                                                 strerror(errno));
 894         if (strbuf_getline(&buf, f, '\n')) {
 895                 error(_("cannot read %s: %s"), filename, ferror(f) ?
 896                         strerror(errno) : _("unexpected end of file"));
 897                 fclose(f);
 898                 goto fail;
 899         }
 900         fclose(f);
 901         if (get_sha1_hex(buf.buf, sha1) || buf.buf[40] != '\0') {
 902                 error(_("stored pre-cherry-pick HEAD file '%s' is corrupt"),
 903                         filename);
 904                 goto fail;
 905         }
 906         if (reset_for_rollback(sha1))
 907                 goto fail;
 908         remove_sequencer_state();
 909         strbuf_release(&buf);
 910         return 0;
 911 fail:
 912         strbuf_release(&buf);
 913         return -1;
 914 }
 915
 916 static void save_todo(struct commit_list *todo_list, struct replay_opts *opts)
 917 {
 918         const char *todo_file = git_path(SEQ_TODO_FILE);
 919         static struct lock_file todo_lock;
 920         struct strbuf buf = STRBUF_INIT;
 921         int fd;
 922
 923         fd = hold_lock_file_for_update(&todo_lock, todo_file, LOCK_DIE_ON_ERROR);
 924         if (format_todo(&buf, todo_list, opts) < 0)
 925                 die(_("Could not format %s."), todo_file);
 926         if (write_in_full(fd, buf.buf, buf.len) < 0) {
 927                 strbuf_release(&buf);
 928                 die_errno(_("Could not write to %s"), todo_file);
 929         }
 930         if (commit_lock_file(&todo_lock) < 0) {
 931                 strbuf_release(&buf);
 932                 die(_("Error wrapping up %s."), todo_file);
 933         }
 934         strbuf_release(&buf);
 935 }
 936
 937 static void save_opts(struct replay_opts *opts)
 938 {
 939         const char *opts_file = git_path(SEQ_OPTS_FILE);
 940
 941         if (opts->no_commit)
 942                 git_config_set_in_file(opts_file, "options.no-commit", "true");
 943         if (opts->edit)
 944                 git_config_set_in_file(opts_file, "options.edit", "true");
 945         if (opts->signoff)
 946                 git_config_set_in_file(opts_file, "options.signoff", "true");
 947         if (opts->record_origin)
 948                 git_config_set_in_file(opts_file, "options.record-origin", "true");
 949         if (opts->allow_ff)
 950                 git_config_set_in_file(opts_file, "options.allow-ff", "true");
 951         if (opts->mainline) {
 952                 struct strbuf buf = STRBUF_INIT;
 953                 strbuf_addf(&buf, "%d", opts->mainline);
 954                 git_config_set_in_file(opts_file, "options.mainline", buf.buf);
 955                 strbuf_release(&buf);
 956         }
 957         if (opts->strategy)
 958                 git_config_set_in_file(opts_file, "options.strategy", opts->strategy);
 959         if (opts->gpg_sign)
 960                 git_config_set_in_file(opts_file, "options.gpg-sign", opts->gpg_sign);
 961         if (opts->xopts) {
 962                 int i;
 963                 for (i = 0; i < opts->xopts_nr; i++)
 964                         git_config_set_multivar_in_file(opts_file,
 965                                                         "options.strategy-option",
 966                                                         opts->xopts[i], "^$", 0);
 967         }
 968 }
 969
 970 static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
 971 {
 972         struct commit_list *cur;
 973         int res;
 974
 975         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
 976         if (opts->allow_ff)
 977                 assert(!(opts->signoff || opts->no_commit ||
 978                                 opts->record_origin || opts->edit));
 979         read_and_refresh_cache(opts);
 980
 981         for (cur = todo_list; cur; cur = cur->next) {
 982                 save_todo(cur, opts);
 983                 res = do_pick_commit(cur->item, opts);
 984                 if (res)
 985                         return res;
 986         }
 987
 988         /*
 989          * Sequence of picks finished successfully; cleanup by
 990          * removing the .git/sequencer directory
 991          */
 992         remove_sequencer_state();
 993         return 0;
 994 }
 995
 996 static int continue_single_pick(void)
 997 {
 998         const char *argv[] = { "commit", NULL };
 999
1000         if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
1001             !file_exists(git_path("REVERT_HEAD")))
1002                 return error(_("no cherry-pick or revert in progress"));
1003         return run_command_v_opt(argv, RUN_GIT_CMD);
1004 }
1005
1006 static int sequencer_continue(struct replay_opts *opts)
1007 {
1008         struct commit_list *todo_list = NULL;
1009
1010         if (!file_exists(git_path(SEQ_TODO_FILE)))
1011                 return continue_single_pick();
1012         read_populate_opts(&opts);
1013         read_populate_todo(&todo_list, opts);
1014
1015         /* Verify that the conflict has been resolved */
1016         if (file_exists(git_path("CHERRY_PICK_HEAD")) ||
1017             file_exists(git_path("REVERT_HEAD"))) {
1018                 int ret = continue_single_pick();
1019                 if (ret)
1020                         return ret;
1021         }
1022         if (index_differs_from("HEAD", 0))
1023                 return error_dirty_index(opts);
1024         todo_list = todo_list->next;
1025         return pick_commits(todo_list, opts);
1026 }
1027
1028 static int single_pick(struct commit *cmit, struct replay_opts *opts)
1029 {
1030         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
1031         return do_pick_commit(cmit, opts);
1032 }
1033
1034 int sequencer_pick_revisions(struct replay_opts *opts)
1035 {
1036         struct commit_list *todo_list = NULL;
1037         unsigned char sha1[20];
1038         int i;
1039
1040         if (opts->subcommand == REPLAY_NONE)
1041                 assert(opts->revs);
1042
1043         read_and_refresh_cache(opts);
1044
1045         /*
1046          * Decide what to do depending on the arguments; a fresh
1047          * cherry-pick should be handled differently from an existing
1048          * one that is being continued
1049          */
1050         if (opts->subcommand == REPLAY_REMOVE_STATE) {
1051                 remove_sequencer_state();
1052                 return 0;
1053         }
1054         if (opts->subcommand == REPLAY_ROLLBACK)
1055                 return sequencer_rollback(opts);
1056         if (opts->subcommand == REPLAY_CONTINUE)
1057                 return sequencer_continue(opts);
1058
1059         for (i = 0; i < opts->revs->pending.nr; i++) {
1060                 unsigned char sha1[20];
1061                 const char *name = opts->revs->pending.objects[i].name;
1062
1063                 /* This happens when using --stdin. */
1064                 if (!strlen(name))
1065                         continue;
1066
1067                 if (!get_sha1(name, sha1)) {
1068                         if (!lookup_commit_reference_gently(sha1, 1)) {
1069                                 enum object_type type = sha1_object_info(sha1, NULL);
1070                                 die(_("%s: can't cherry-pick a %s"), name, typename(type));
1071                         }
1072                 } else
1073                         die(_("%s: bad revision"), name);
1074         }
1075
1076         /*
1077          * If we were called as "git cherry-pick <commit>", just
1078          * cherry-pick/revert it, set CHERRY_PICK_HEAD /
1079          * REVERT_HEAD, and don't touch the sequencer state.
1080          * This means it is possible to cherry-pick in the middle
1081          * of a cherry-pick sequence.
1082          */
1083         if (opts->revs->cmdline.nr == 1 &&
1084             opts->revs->cmdline.rev->whence == REV_CMD_REV &&
1085             opts->revs->no_walk &&
1086             !opts->revs->cmdline.rev->flags) {
1087                 struct commit *cmit;
1088                 if (prepare_revision_walk(opts->revs))
1089                         die(_("revision walk setup failed"));
1090                 cmit = get_revision(opts->revs);
1091                 if (!cmit || get_revision(opts->revs))
1092                         die("BUG: expected exactly one commit from walk");
1093                 return single_pick(cmit, opts);
1094         }
1095
1096         /*
1097          * Start a new cherry-pick/ revert sequence; but
1098          * first, make sure that an existing one isn't in
1099          * progress
1100          */
1101
1102         walk_revs_populate_todo(&todo_list, opts);
1103         if (create_seq_dir() < 0)
1104                 return -1;
1105         if (get_sha1("HEAD", sha1)) {
1106                 if (opts->action == REPLAY_REVERT)
1107                         return error(_("Can't revert as initial commit"));
1108                 return error(_("Can't cherry-pick into empty head"));
1109         }
1110         save_head(sha1_to_hex(sha1));
1111         save_opts(opts);
1112         return pick_commits(todo_list, opts);
1113 }
1114
1115 void append_signoff(struct strbuf *msgbuf, int ignore_footer, unsigned flag)
1116 {
1117         unsigned no_dup_sob = flag & APPEND_SIGNOFF_DEDUP;
1118         struct strbuf sob = STRBUF_INIT;
1119         int has_footer;
1120
1121         strbuf_addstr(&sob, sign_off_header);
1122         strbuf_addstr(&sob, fmt_name(getenv("GIT_COMMITTER_NAME"),
1123                                 getenv("GIT_COMMITTER_EMAIL")));
1124         strbuf_addch(&sob, '\n');
1125
1126         /*
1127          * If the whole message buffer is equal to the sob, pretend that we
1128          * found a conforming footer with a matching sob
1129          */
1130         if (msgbuf->len - ignore_footer == sob.len &&
1131             !strncmp(msgbuf->buf, sob.buf, sob.len))
1132                 has_footer = 3;
1133         else
1134                 has_footer = has_conforming_footer(msgbuf, &sob, ignore_footer);
1135
1136         if (!has_footer) {
1137                 const char *append_newlines = NULL;
1138                 size_t len = msgbuf->len - ignore_footer;
1139
1140                 if (!len) {
1141                         /*
1142                          * The buffer is completely empty.  Leave foom for
1143                          * the title and body to be filled in by the user.
1144                          */
1145                         append_newlines = "\n\n";
1146                 } else if (msgbuf->buf[len - 1] != '\n') {
1147                         /*
1148                          * Incomplete line.  Complete the line and add a
1149                          * blank one so that there is an empty line between
1150                          * the message body and the sob.
1151                          */
1152                         append_newlines = "\n\n";
1153                 } else if (len == 1) {
1154                         /*
1155                          * Buffer contains a single newline.  Add another
1156                          * so that we leave room for the title and body.
1157                          */
1158                         append_newlines = "\n";
1159                 } else if (msgbuf->buf[len - 2] != '\n') {
1160                         /*
1161                          * Buffer ends with a single newline.  Add another
1162                          * so that there is an empty line between the message
1163                          * body and the sob.
1164                          */
1165                         append_newlines = "\n";
1166                 } /* else, the buffer already ends with two newlines. */
1167
1168                 if (append_newlines)
1169                         strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0,
1170                                 append_newlines, strlen(append_newlines));
1171         }
1172
1173         if (has_footer != 3 && (!no_dup_sob || has_footer != 2))
1174                 strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0,
1175                                 sob.buf, sob.len);
1176
1177         strbuf_release(&sob);
1178 }