builtin/revert.c

   1 #include "cache.h"
   2 #include "builtin.h"
   3 #include "object.h"
   4 #include "commit.h"
   5 #include "tag.h"
   6 #include "run-command.h"
   7 #include "exec_cmd.h"
   8 #include "utf8.h"
   9 #include "parse-options.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 "dir.h"
  17 #include "sequencer.h"
  18
  19 /*
  20  * This implements the builtins revert and cherry-pick.
  21  *
  22  * Copyright (c) 2007 Johannes E. Schindelin
  23  *
  24  * Based on git-revert.sh, which is
  25  *
  26  * Copyright (c) 2005 Linus Torvalds
  27  * Copyright (c) 2005 Junio C Hamano
  28  */
  29
  30 static const char * const revert_usage[] = {
  31         "git revert [options] <commit-ish>",
  32         "git revert <subcommand>",
  33         NULL
  34 };
  35
  36 static const char * const cherry_pick_usage[] = {
  37         "git cherry-pick [options] <commit-ish>",
  38         "git cherry-pick <subcommand>",
  39         NULL
  40 };
  41
  42 enum replay_action { REVERT, CHERRY_PICK };
  43 enum replay_subcommand { REPLAY_NONE, REPLAY_REMOVE_STATE, REPLAY_CONTINUE };
  44
  45 struct replay_opts {
  46         enum replay_action action;
  47         enum replay_subcommand subcommand;
  48
  49         /* Boolean options */
  50         int edit;
  51         int record_origin;
  52         int no_commit;
  53         int signoff;
  54         int allow_ff;
  55         int allow_rerere_auto;
  56
  57         int mainline;
  58         int commit_argc;
  59         const char **commit_argv;
  60
  61         /* Merge strategy */
  62         const char *strategy;
  63         const char **xopts;
  64         size_t xopts_nr, xopts_alloc;
  65 };
  66
  67 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
  68
  69 static const char *action_name(const struct replay_opts *opts)
  70 {
  71         return opts->action == REVERT ? "revert" : "cherry-pick";
  72 }
  73
  74 static char *get_encoding(const char *message);
  75
  76 static const char * const *revert_or_cherry_pick_usage(struct replay_opts *opts)
  77 {
  78         return opts->action == REVERT ? revert_usage : cherry_pick_usage;
  79 }
  80
  81 static int option_parse_x(const struct option *opt,
  82                           const char *arg, int unset)
  83 {
  84         struct replay_opts **opts_ptr = opt->value;
  85         struct replay_opts *opts = *opts_ptr;
  86
  87         if (unset)
  88                 return 0;
  89
  90         ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
  91         opts->xopts[opts->xopts_nr++] = xstrdup(arg);
  92         return 0;
  93 }
  94
  95 static void verify_opt_compatible(const char *me, const char *base_opt, ...)
  96 {
  97         const char *this_opt;
  98         va_list ap;
  99
 100         va_start(ap, base_opt);
 101         while ((this_opt = va_arg(ap, const char *))) {
 102                 if (va_arg(ap, int))
 103                         break;
 104         }
 105         va_end(ap);
 106
 107         if (this_opt)
 108                 die(_("%s: %s cannot be used with %s"), me, this_opt, base_opt);
 109 }
 110
 111 static void verify_opt_mutually_compatible(const char *me, ...)
 112 {
 113         const char *opt1, *opt2 = NULL;
 114         va_list ap;
 115
 116         va_start(ap, me);
 117         while ((opt1 = va_arg(ap, const char *))) {
 118                 if (va_arg(ap, int))
 119                         break;
 120         }
 121         if (opt1) {
 122                 while ((opt2 = va_arg(ap, const char *))) {
 123                         if (va_arg(ap, int))
 124                                 break;
 125                 }
 126         }
 127
 128         if (opt1 && opt2)
 129                 die(_("%s: %s cannot be used with %s"), me, opt1, opt2);
 130 }
 131
 132 static void parse_args(int argc, const char **argv, struct replay_opts *opts)
 133 {
 134         const char * const * usage_str = revert_or_cherry_pick_usage(opts);
 135         const char *me = action_name(opts);
 136         int remove_state = 0;
 137         int contin = 0;
 138         struct option options[] = {
 139                 OPT_BOOLEAN(0, "quit", &remove_state, "end revert or cherry-pick sequence"),
 140                 OPT_BOOLEAN(0, "continue", &contin, "resume revert or cherry-pick sequence"),
 141                 OPT_BOOLEAN('n', "no-commit", &opts->no_commit, "don't automatically commit"),
 142                 OPT_BOOLEAN('e', "edit", &opts->edit, "edit the commit message"),
 143                 OPT_NOOP_NOARG('r', NULL),
 144                 OPT_BOOLEAN('s', "signoff", &opts->signoff, "add Signed-off-by:"),
 145                 OPT_INTEGER('m', "mainline", &opts->mainline, "parent number"),
 146                 OPT_RERERE_AUTOUPDATE(&opts->allow_rerere_auto),
 147                 OPT_STRING(0, "strategy", &opts->strategy, "strategy", "merge strategy"),
 148                 OPT_CALLBACK('X', "strategy-option", &opts, "option",
 149                         "option for merge strategy", option_parse_x),
 150                 { OPTION_BOOLEAN, 0, "reset", &remove_state, NULL,
 151                         "alias for --quit (deprecated)",
 152                         PARSE_OPT_HIDDEN | PARSE_OPT_NOARG },
 153                 OPT_END(),
 154                 OPT_END(),
 155                 OPT_END(),
 156         };
 157
 158         if (opts->action == CHERRY_PICK) {
 159                 struct option cp_extra[] = {
 160                         OPT_BOOLEAN('x', NULL, &opts->record_origin, "append commit name"),
 161                         OPT_BOOLEAN(0, "ff", &opts->allow_ff, "allow fast-forward"),
 162                         OPT_END(),
 163                 };
 164                 if (parse_options_concat(options, ARRAY_SIZE(options), cp_extra))
 165                         die(_("program error"));
 166         }
 167
 168         opts->commit_argc = parse_options(argc, argv, NULL, options, usage_str,
 169                                         PARSE_OPT_KEEP_ARGV0 |
 170                                         PARSE_OPT_KEEP_UNKNOWN);
 171
 172         /* Check for incompatible subcommands */
 173         verify_opt_mutually_compatible(me,
 174                                 "--quit", remove_state,
 175                                 "--continue", contin,
 176                                 NULL);
 177
 178         /* Set the subcommand */
 179         if (remove_state)
 180                 opts->subcommand = REPLAY_REMOVE_STATE;
 181         else if (contin)
 182                 opts->subcommand = REPLAY_CONTINUE;
 183         else
 184                 opts->subcommand = REPLAY_NONE;
 185
 186         /* Check for incompatible command line arguments */
 187         if (opts->subcommand != REPLAY_NONE) {
 188                 char *this_operation;
 189                 if (opts->subcommand == REPLAY_REMOVE_STATE)
 190                         this_operation = "--quit";
 191                 else
 192                         this_operation = "--continue";
 193
 194                 verify_opt_compatible(me, this_operation,
 195                                 "--no-commit", opts->no_commit,
 196                                 "--signoff", opts->signoff,
 197                                 "--mainline", opts->mainline,
 198                                 "--strategy", opts->strategy ? 1 : 0,
 199                                 "--strategy-option", opts->xopts ? 1 : 0,
 200                                 "-x", opts->record_origin,
 201                                 "--ff", opts->allow_ff,
 202                                 NULL);
 203         }
 204
 205         else if (opts->commit_argc < 2)
 206                 usage_with_options(usage_str, options);
 207
 208         if (opts->allow_ff)
 209                 verify_opt_compatible(me, "--ff",
 210                                 "--signoff", opts->signoff,
 211                                 "--no-commit", opts->no_commit,
 212                                 "-x", opts->record_origin,
 213                                 "--edit", opts->edit,
 214                                 NULL);
 215         opts->commit_argv = argv;
 216 }
 217
 218 struct commit_message {
 219         char *parent_label;
 220         const char *label;
 221         const char *subject;
 222         char *reencoded_message;
 223         const char *message;
 224 };
 225
 226 static int get_message(struct commit *commit, struct commit_message *out)
 227 {
 228         const char *encoding;
 229         const char *abbrev, *subject;
 230         int abbrev_len, subject_len;
 231         char *q;
 232
 233         if (!commit->buffer)
 234                 return -1;
 235         encoding = get_encoding(commit->buffer);
 236         if (!encoding)
 237                 encoding = "UTF-8";
 238         if (!git_commit_encoding)
 239                 git_commit_encoding = "UTF-8";
 240
 241         out->reencoded_message = NULL;
 242         out->message = commit->buffer;
 243         if (strcmp(encoding, git_commit_encoding))
 244                 out->reencoded_message = reencode_string(commit->buffer,
 245                                         git_commit_encoding, encoding);
 246         if (out->reencoded_message)
 247                 out->message = out->reencoded_message;
 248
 249         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
 250         abbrev_len = strlen(abbrev);
 251
 252         subject_len = find_commit_subject(out->message, &subject);
 253
 254         out->parent_label = xmalloc(strlen("parent of ") + abbrev_len +
 255                               strlen("... ") + subject_len + 1);
 256         q = out->parent_label;
 257         q = mempcpy(q, "parent of ", strlen("parent of "));
 258         out->label = q;
 259         q = mempcpy(q, abbrev, abbrev_len);
 260         q = mempcpy(q, "... ", strlen("... "));
 261         out->subject = q;
 262         q = mempcpy(q, subject, subject_len);
 263         *q = '\0';
 264         return 0;
 265 }
 266
 267 static void free_message(struct commit_message *msg)
 268 {
 269         free(msg->parent_label);
 270         free(msg->reencoded_message);
 271 }
 272
 273 static char *get_encoding(const char *message)
 274 {
 275         const char *p = message, *eol;
 276
 277         while (*p && *p != '\n') {
 278                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
 279                         ; /* do nothing */
 280                 if (!prefixcmp(p, "encoding ")) {
 281                         char *result = xmalloc(eol - 8 - p);
 282                         strlcpy(result, p + 9, eol - 8 - p);
 283                         return result;
 284                 }
 285                 p = eol;
 286                 if (*p == '\n')
 287                         p++;
 288         }
 289         return NULL;
 290 }
 291
 292 static void write_cherry_pick_head(struct commit *commit)
 293 {
 294         const char *filename;
 295         int fd;
 296         struct strbuf buf = STRBUF_INIT;
 297
 298         strbuf_addf(&buf, "%s\n", sha1_to_hex(commit->object.sha1));
 299
 300         filename = git_path("CHERRY_PICK_HEAD");
 301         fd = open(filename, O_WRONLY | O_CREAT, 0666);
 302         if (fd < 0)
 303                 die_errno(_("Could not open '%s' for writing"), filename);
 304         if (write_in_full(fd, buf.buf, buf.len) != buf.len || close(fd))
 305                 die_errno(_("Could not write to '%s'"), filename);
 306         strbuf_release(&buf);
 307 }
 308
 309 static void print_advice(int show_hint)
 310 {
 311         char *msg = getenv("GIT_CHERRY_PICK_HELP");
 312
 313         if (msg) {
 314                 fprintf(stderr, "%s\n", msg);
 315                 /*
 316                  * A conflict has occured but the porcelain
 317                  * (typically rebase --interactive) wants to take care
 318                  * of the commit itself so remove CHERRY_PICK_HEAD
 319                  */
 320                 unlink(git_path("CHERRY_PICK_HEAD"));
 321                 return;
 322         }
 323
 324         if (show_hint) {
 325                 advise("after resolving the conflicts, mark the corrected paths");
 326                 advise("with 'git add <paths>' or 'git rm <paths>'");
 327                 advise("and commit the result with 'git commit'");
 328         }
 329 }
 330
 331 static void write_message(struct strbuf *msgbuf, const char *filename)
 332 {
 333         static struct lock_file msg_file;
 334
 335         int msg_fd = hold_lock_file_for_update(&msg_file, filename,
 336                                                LOCK_DIE_ON_ERROR);
 337         if (write_in_full(msg_fd, msgbuf->buf, msgbuf->len) < 0)
 338                 die_errno(_("Could not write to %s"), filename);
 339         strbuf_release(msgbuf);
 340         if (commit_lock_file(&msg_file) < 0)
 341                 die(_("Error wrapping up %s"), filename);
 342 }
 343
 344 static struct tree *empty_tree(void)
 345 {
 346         return lookup_tree((const unsigned char *)EMPTY_TREE_SHA1_BIN);
 347 }
 348
 349 static int error_dirty_index(struct replay_opts *opts)
 350 {
 351         if (read_cache_unmerged())
 352                 return error_resolve_conflict(action_name(opts));
 353
 354         /* Different translation strings for cherry-pick and revert */
 355         if (opts->action == CHERRY_PICK)
 356                 error(_("Your local changes would be overwritten by cherry-pick."));
 357         else
 358                 error(_("Your local changes would be overwritten by revert."));
 359
 360         if (advice_commit_before_merge)
 361                 advise(_("Commit your changes or stash them to proceed."));
 362         return -1;
 363 }
 364
 365 static int fast_forward_to(const unsigned char *to, const unsigned char *from)
 366 {
 367         struct ref_lock *ref_lock;
 368
 369         read_cache();
 370         if (checkout_fast_forward(from, to))
 371                 exit(1); /* the callee should have complained already */
 372         ref_lock = lock_any_ref_for_update("HEAD", from, 0);
 373         return write_ref_sha1(ref_lock, to, "cherry-pick");
 374 }
 375
 376 static int do_recursive_merge(struct commit *base, struct commit *next,
 377                               const char *base_label, const char *next_label,
 378                               unsigned char *head, struct strbuf *msgbuf,
 379                               struct replay_opts *opts)
 380 {
 381         struct merge_options o;
 382         struct tree *result, *next_tree, *base_tree, *head_tree;
 383         int clean, index_fd;
 384         const char **xopt;
 385         static struct lock_file index_lock;
 386
 387         index_fd = hold_locked_index(&index_lock, 1);
 388
 389         read_cache();
 390
 391         init_merge_options(&o);
 392         o.ancestor = base ? base_label : "(empty tree)";
 393         o.branch1 = "HEAD";
 394         o.branch2 = next ? next_label : "(empty tree)";
 395
 396         head_tree = parse_tree_indirect(head);
 397         next_tree = next ? next->tree : empty_tree();
 398         base_tree = base ? base->tree : empty_tree();
 399
 400         for (xopt = opts->xopts; xopt != opts->xopts + opts->xopts_nr; xopt++)
 401                 parse_merge_opt(&o, *xopt);
 402
 403         clean = merge_trees(&o,
 404                             head_tree,
 405                             next_tree, base_tree, &result);
 406
 407         if (active_cache_changed &&
 408             (write_cache(index_fd, active_cache, active_nr) ||
 409              commit_locked_index(&index_lock)))
 410                 /* TRANSLATORS: %s will be "revert" or "cherry-pick" */
 411                 die(_("%s: Unable to write new index file"), action_name(opts));
 412         rollback_lock_file(&index_lock);
 413
 414         if (!clean) {
 415                 int i;
 416                 strbuf_addstr(msgbuf, "\nConflicts:\n\n");
 417                 for (i = 0; i < active_nr;) {
 418                         struct cache_entry *ce = active_cache[i++];
 419                         if (ce_stage(ce)) {
 420                                 strbuf_addch(msgbuf, '\t');
 421                                 strbuf_addstr(msgbuf, ce->name);
 422                                 strbuf_addch(msgbuf, '\n');
 423                                 while (i < active_nr && !strcmp(ce->name,
 424                                                 active_cache[i]->name))
 425                                         i++;
 426                         }
 427                 }
 428         }
 429
 430         return !clean;
 431 }
 432
 433 /*
 434  * If we are cherry-pick, and if the merge did not result in
 435  * hand-editing, we will hit this commit and inherit the original
 436  * author date and name.
 437  * If we are revert, or if our cherry-pick results in a hand merge,
 438  * we had better say that the current user is responsible for that.
 439  */
 440 static int run_git_commit(const char *defmsg, struct replay_opts *opts)
 441 {
 442         /* 6 is max possible length of our args array including NULL */
 443         const char *args[6];
 444         int i = 0;
 445
 446         args[i++] = "commit";
 447         args[i++] = "-n";
 448         if (opts->signoff)
 449                 args[i++] = "-s";
 450         if (!opts->edit) {
 451                 args[i++] = "-F";
 452                 args[i++] = defmsg;
 453         }
 454         args[i] = NULL;
 455
 456         return run_command_v_opt(args, RUN_GIT_CMD);
 457 }
 458
 459 static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
 460 {
 461         unsigned char head[20];
 462         struct commit *base, *next, *parent;
 463         const char *base_label, *next_label;
 464         struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
 465         char *defmsg = NULL;
 466         struct strbuf msgbuf = STRBUF_INIT;
 467         int res;
 468
 469         if (opts->no_commit) {
 470                 /*
 471                  * We do not intend to commit immediately.  We just want to
 472                  * merge the differences in, so let's compute the tree
 473                  * that represents the "current" state for merge-recursive
 474                  * to work on.
 475                  */
 476                 if (write_cache_as_tree(head, 0, NULL))
 477                         die (_("Your index file is unmerged."));
 478         } else {
 479                 if (get_sha1("HEAD", head))
 480                         return error(_("You do not have a valid HEAD"));
 481                 if (index_differs_from("HEAD", 0))
 482                         return error_dirty_index(opts);
 483         }
 484         discard_cache();
 485
 486         if (!commit->parents) {
 487                 parent = NULL;
 488         }
 489         else if (commit->parents->next) {
 490                 /* Reverting or cherry-picking a merge commit */
 491                 int cnt;
 492                 struct commit_list *p;
 493
 494                 if (!opts->mainline)
 495                         return error(_("Commit %s is a merge but no -m option was given."),
 496                                 sha1_to_hex(commit->object.sha1));
 497
 498                 for (cnt = 1, p = commit->parents;
 499                      cnt != opts->mainline && p;
 500                      cnt++)
 501                         p = p->next;
 502                 if (cnt != opts->mainline || !p)
 503                         return error(_("Commit %s does not have parent %d"),
 504                                 sha1_to_hex(commit->object.sha1), opts->mainline);
 505                 parent = p->item;
 506         } else if (0 < opts->mainline)
 507                 return error(_("Mainline was specified but commit %s is not a merge."),
 508                         sha1_to_hex(commit->object.sha1));
 509         else
 510                 parent = commit->parents->item;
 511
 512         if (opts->allow_ff && parent && !hashcmp(parent->object.sha1, head))
 513                 return fast_forward_to(commit->object.sha1, head);
 514
 515         if (parent && parse_commit(parent) < 0)
 516                 /* TRANSLATORS: The first %s will be "revert" or
 517                    "cherry-pick", the second %s a SHA1 */
 518                 return error(_("%s: cannot parse parent commit %s"),
 519                         action_name(opts), sha1_to_hex(parent->object.sha1));
 520
 521         if (get_message(commit, &msg) != 0)
 522                 return error(_("Cannot get commit message for %s"),
 523                         sha1_to_hex(commit->object.sha1));
 524
 525         /*
 526          * "commit" is an existing commit.  We would want to apply
 527          * the difference it introduces since its first parent "prev"
 528          * on top of the current HEAD if we are cherry-pick.  Or the
 529          * reverse of it if we are revert.
 530          */
 531
 532         defmsg = git_pathdup("MERGE_MSG");
 533
 534         if (opts->action == REVERT) {
 535                 base = commit;
 536                 base_label = msg.label;
 537                 next = parent;
 538                 next_label = msg.parent_label;
 539                 strbuf_addstr(&msgbuf, "Revert \"");
 540                 strbuf_addstr(&msgbuf, msg.subject);
 541                 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
 542                 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 543
 544                 if (commit->parents && commit->parents->next) {
 545                         strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
 546                         strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
 547                 }
 548                 strbuf_addstr(&msgbuf, ".\n");
 549         } else {
 550                 const char *p;
 551
 552                 base = parent;
 553                 base_label = msg.parent_label;
 554                 next = commit;
 555                 next_label = msg.label;
 556
 557                 /*
 558                  * Append the commit log message to msgbuf; it starts
 559                  * after the tree, parent, author, committer
 560                  * information followed by "\n\n".
 561                  */
 562                 p = strstr(msg.message, "\n\n");
 563                 if (p) {
 564                         p += 2;
 565                         strbuf_addstr(&msgbuf, p);
 566                 }
 567
 568                 if (opts->record_origin) {
 569                         strbuf_addstr(&msgbuf, "(cherry picked from commit ");
 570                         strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 571                         strbuf_addstr(&msgbuf, ")\n");
 572                 }
 573         }
 574
 575         if (!opts->strategy || !strcmp(opts->strategy, "recursive") || opts->action == REVERT) {
 576                 res = do_recursive_merge(base, next, base_label, next_label,
 577                                          head, &msgbuf, opts);
 578                 write_message(&msgbuf, defmsg);
 579         } else {
 580                 struct commit_list *common = NULL;
 581                 struct commit_list *remotes = NULL;
 582
 583                 write_message(&msgbuf, defmsg);
 584
 585                 commit_list_insert(base, &common);
 586                 commit_list_insert(next, &remotes);
 587                 res = try_merge_command(opts->strategy, opts->xopts_nr, opts->xopts,
 588                                         common, sha1_to_hex(head), remotes);
 589                 free_commit_list(common);
 590                 free_commit_list(remotes);
 591         }
 592
 593         /*
 594          * If the merge was clean or if it failed due to conflict, we write
 595          * CHERRY_PICK_HEAD for the subsequent invocation of commit to use.
 596          * However, if the merge did not even start, then we don't want to
 597          * write it at all.
 598          */
 599         if (opts->action == CHERRY_PICK && !opts->no_commit && (res == 0 || res == 1))
 600                 write_cherry_pick_head(commit);
 601
 602         if (res) {
 603                 error(opts->action == REVERT
 604                       ? _("could not revert %s... %s")
 605                       : _("could not apply %s... %s"),
 606                       find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV),
 607                       msg.subject);
 608                 print_advice(res == 1);
 609                 rerere(opts->allow_rerere_auto);
 610         } else {
 611                 if (!opts->no_commit)
 612                         res = run_git_commit(defmsg, opts);
 613         }
 614
 615         free_message(&msg);
 616         free(defmsg);
 617
 618         return res;
 619 }
 620
 621 static void prepare_revs(struct rev_info *revs, struct replay_opts *opts)
 622 {
 623         int argc;
 624
 625         init_revisions(revs, NULL);
 626         revs->no_walk = 1;
 627         if (opts->action != REVERT)
 628                 revs->reverse = 1;
 629
 630         argc = setup_revisions(opts->commit_argc, opts->commit_argv, revs, NULL);
 631         if (argc > 1)
 632                 usage(*revert_or_cherry_pick_usage(opts));
 633
 634         if (prepare_revision_walk(revs))
 635                 die(_("revision walk setup failed"));
 636
 637         if (!revs->commits)
 638                 die(_("empty commit set passed"));
 639 }
 640
 641 static void read_and_refresh_cache(struct replay_opts *opts)
 642 {
 643         static struct lock_file index_lock;
 644         int index_fd = hold_locked_index(&index_lock, 0);
 645         if (read_index_preload(&the_index, NULL) < 0)
 646                 die(_("git %s: failed to read the index"), action_name(opts));
 647         refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
 648         if (the_index.cache_changed) {
 649                 if (write_index(&the_index, index_fd) ||
 650                     commit_locked_index(&index_lock))
 651                         die(_("git %s: failed to refresh the index"), action_name(opts));
 652         }
 653         rollback_lock_file(&index_lock);
 654 }
 655
 656 /*
 657  * Append a commit to the end of the commit_list.
 658  *
 659  * next starts by pointing to the variable that holds the head of an
 660  * empty commit_list, and is updated to point to the "next" field of
 661  * the last item on the list as new commits are appended.
 662  *
 663  * Usage example:
 664  *
 665  *     struct commit_list *list;
 666  *     struct commit_list **next = &list;
 667  *
 668  *     next = commit_list_append(c1, next);
 669  *     next = commit_list_append(c2, next);
 670  *     assert(commit_list_count(list) == 2);
 671  *     return list;
 672  */
 673 static struct commit_list **commit_list_append(struct commit *commit,
 674                                                struct commit_list **next)
 675 {
 676         struct commit_list *new = xmalloc(sizeof(struct commit_list));
 677         new->item = commit;
 678         *next = new;
 679         new->next = NULL;
 680         return &new->next;
 681 }
 682
 683 static int format_todo(struct strbuf *buf, struct commit_list *todo_list,
 684                 struct replay_opts *opts)
 685 {
 686         struct commit_list *cur = NULL;
 687         struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
 688         const char *sha1_abbrev = NULL;
 689         const char *action_str = opts->action == REVERT ? "revert" : "pick";
 690
 691         for (cur = todo_list; cur; cur = cur->next) {
 692                 sha1_abbrev = find_unique_abbrev(cur->item->object.sha1, DEFAULT_ABBREV);
 693                 if (get_message(cur->item, &msg))
 694                         return error(_("Cannot get commit message for %s"), sha1_abbrev);
 695                 strbuf_addf(buf, "%s %s %s\n", action_str, sha1_abbrev, msg.subject);
 696         }
 697         return 0;
 698 }
 699
 700 static struct commit *parse_insn_line(char *start, struct replay_opts *opts)
 701 {
 702         unsigned char commit_sha1[20];
 703         char sha1_abbrev[40];
 704         enum replay_action action;
 705         int insn_len = 0;
 706         char *p, *q;
 707
 708         if (!prefixcmp(start, "pick ")) {
 709                 action = CHERRY_PICK;
 710                 insn_len = strlen("pick");
 711                 p = start + insn_len + 1;
 712         } else if (!prefixcmp(start, "revert ")) {
 713                 action = REVERT;
 714                 insn_len = strlen("revert");
 715                 p = start + insn_len + 1;
 716         } else
 717                 return NULL;
 718
 719         q = strchr(p, ' ');
 720         if (!q)
 721                 return NULL;
 722         q++;
 723
 724         strlcpy(sha1_abbrev, p, q - p);
 725
 726         /*
 727          * Verify that the action matches up with the one in
 728          * opts; we don't support arbitrary instructions
 729          */
 730         if (action != opts->action) {
 731                 const char *action_str;
 732                 action_str = action == REVERT ? "revert" : "cherry-pick";
 733                 error(_("Cannot %s during a %s"), action_str, action_name(opts));
 734                 return NULL;
 735         }
 736
 737         if (get_sha1(sha1_abbrev, commit_sha1) < 0)
 738                 return NULL;
 739
 740         return lookup_commit_reference(commit_sha1);
 741 }
 742
 743 static int parse_insn_buffer(char *buf, struct commit_list **todo_list,
 744                         struct replay_opts *opts)
 745 {
 746         struct commit_list **next = todo_list;
 747         struct commit *commit;
 748         char *p = buf;
 749         int i;
 750
 751         for (i = 1; *p; i++) {
 752                 commit = parse_insn_line(p, opts);
 753                 if (!commit)
 754                         return error(_("Could not parse line %d."), i);
 755                 next = commit_list_append(commit, next);
 756                 p = strchrnul(p, '\n');
 757                 if (*p)
 758                         p++;
 759         }
 760         if (!*todo_list)
 761                 return error(_("No commits parsed."));
 762         return 0;
 763 }
 764
 765 static void read_populate_todo(struct commit_list **todo_list,
 766                         struct replay_opts *opts)
 767 {
 768         const char *todo_file = git_path(SEQ_TODO_FILE);
 769         struct strbuf buf = STRBUF_INIT;
 770         int fd, res;
 771
 772         fd = open(todo_file, O_RDONLY);
 773         if (fd < 0)
 774                 die_errno(_("Could not open %s"), todo_file);
 775         if (strbuf_read(&buf, fd, 0) < 0) {
 776                 close(fd);
 777                 strbuf_release(&buf);
 778                 die(_("Could not read %s."), todo_file);
 779         }
 780         close(fd);
 781
 782         res = parse_insn_buffer(buf.buf, todo_list, opts);
 783         strbuf_release(&buf);
 784         if (res)
 785                 die(_("Unusable instruction sheet: %s"), todo_file);
 786 }
 787
 788 static int populate_opts_cb(const char *key, const char *value, void *data)
 789 {
 790         struct replay_opts *opts = data;
 791         int error_flag = 1;
 792
 793         if (!value)
 794                 error_flag = 0;
 795         else if (!strcmp(key, "options.no-commit"))
 796                 opts->no_commit = git_config_bool_or_int(key, value, &error_flag);
 797         else if (!strcmp(key, "options.edit"))
 798                 opts->edit = git_config_bool_or_int(key, value, &error_flag);
 799         else if (!strcmp(key, "options.signoff"))
 800                 opts->signoff = git_config_bool_or_int(key, value, &error_flag);
 801         else if (!strcmp(key, "options.record-origin"))
 802                 opts->record_origin = git_config_bool_or_int(key, value, &error_flag);
 803         else if (!strcmp(key, "options.allow-ff"))
 804                 opts->allow_ff = git_config_bool_or_int(key, value, &error_flag);
 805         else if (!strcmp(key, "options.mainline"))
 806                 opts->mainline = git_config_int(key, value);
 807         else if (!strcmp(key, "options.strategy"))
 808                 git_config_string(&opts->strategy, key, value);
 809         else if (!strcmp(key, "options.strategy-option")) {
 810                 ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
 811                 opts->xopts[opts->xopts_nr++] = xstrdup(value);
 812         } else
 813                 return error(_("Invalid key: %s"), key);
 814
 815         if (!error_flag)
 816                 return error(_("Invalid value for %s: %s"), key, value);
 817
 818         return 0;
 819 }
 820
 821 static void read_populate_opts(struct replay_opts **opts_ptr)
 822 {
 823         const char *opts_file = git_path(SEQ_OPTS_FILE);
 824
 825         if (!file_exists(opts_file))
 826                 return;
 827         if (git_config_from_file(populate_opts_cb, opts_file, *opts_ptr) < 0)
 828                 die(_("Malformed options sheet: %s"), opts_file);
 829 }
 830
 831 static void walk_revs_populate_todo(struct commit_list **todo_list,
 832                                 struct replay_opts *opts)
 833 {
 834         struct rev_info revs;
 835         struct commit *commit;
 836         struct commit_list **next;
 837
 838         prepare_revs(&revs, opts);
 839
 840         next = todo_list;
 841         while ((commit = get_revision(&revs)))
 842                 next = commit_list_append(commit, next);
 843 }
 844
 845 static int create_seq_dir(void)
 846 {
 847         const char *seq_dir = git_path(SEQ_DIR);
 848
 849         if (file_exists(seq_dir))
 850                 return error(_("%s already exists."), seq_dir);
 851         else if (mkdir(seq_dir, 0777) < 0)
 852                 die_errno(_("Could not create sequencer directory %s"), seq_dir);
 853         return 0;
 854 }
 855
 856 static void save_head(const char *head)
 857 {
 858         const char *head_file = git_path(SEQ_HEAD_FILE);
 859         static struct lock_file head_lock;
 860         struct strbuf buf = STRBUF_INIT;
 861         int fd;
 862
 863         fd = hold_lock_file_for_update(&head_lock, head_file, LOCK_DIE_ON_ERROR);
 864         strbuf_addf(&buf, "%s\n", head);
 865         if (write_in_full(fd, buf.buf, buf.len) < 0)
 866                 die_errno(_("Could not write to %s"), head_file);
 867         if (commit_lock_file(&head_lock) < 0)
 868                 die(_("Error wrapping up %s."), head_file);
 869 }
 870
 871 static void save_todo(struct commit_list *todo_list, struct replay_opts *opts)
 872 {
 873         const char *todo_file = git_path(SEQ_TODO_FILE);
 874         static struct lock_file todo_lock;
 875         struct strbuf buf = STRBUF_INIT;
 876         int fd;
 877
 878         fd = hold_lock_file_for_update(&todo_lock, todo_file, LOCK_DIE_ON_ERROR);
 879         if (format_todo(&buf, todo_list, opts) < 0)
 880                 die(_("Could not format %s."), todo_file);
 881         if (write_in_full(fd, buf.buf, buf.len) < 0) {
 882                 strbuf_release(&buf);
 883                 die_errno(_("Could not write to %s"), todo_file);
 884         }
 885         if (commit_lock_file(&todo_lock) < 0) {
 886                 strbuf_release(&buf);
 887                 die(_("Error wrapping up %s."), todo_file);
 888         }
 889         strbuf_release(&buf);
 890 }
 891
 892 static void save_opts(struct replay_opts *opts)
 893 {
 894         const char *opts_file = git_path(SEQ_OPTS_FILE);
 895
 896         if (opts->no_commit)
 897                 git_config_set_in_file(opts_file, "options.no-commit", "true");
 898         if (opts->edit)
 899                 git_config_set_in_file(opts_file, "options.edit", "true");
 900         if (opts->signoff)
 901                 git_config_set_in_file(opts_file, "options.signoff", "true");
 902         if (opts->record_origin)
 903                 git_config_set_in_file(opts_file, "options.record-origin", "true");
 904         if (opts->allow_ff)
 905                 git_config_set_in_file(opts_file, "options.allow-ff", "true");
 906         if (opts->mainline) {
 907                 struct strbuf buf = STRBUF_INIT;
 908                 strbuf_addf(&buf, "%d", opts->mainline);
 909                 git_config_set_in_file(opts_file, "options.mainline", buf.buf);
 910                 strbuf_release(&buf);
 911         }
 912         if (opts->strategy)
 913                 git_config_set_in_file(opts_file, "options.strategy", opts->strategy);
 914         if (opts->xopts) {
 915                 int i;
 916                 for (i = 0; i < opts->xopts_nr; i++)
 917                         git_config_set_multivar_in_file(opts_file,
 918                                                         "options.strategy-option",
 919                                                         opts->xopts[i], "^$", 0);
 920         }
 921 }
 922
 923 static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
 924 {
 925         struct commit_list *cur;
 926         int res;
 927
 928         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
 929         if (opts->allow_ff)
 930                 assert(!(opts->signoff || opts->no_commit ||
 931                                 opts->record_origin || opts->edit));
 932         read_and_refresh_cache(opts);
 933
 934         for (cur = todo_list; cur; cur = cur->next) {
 935                 save_todo(cur, opts);
 936                 res = do_pick_commit(cur->item, opts);
 937                 if (res) {
 938                         if (!cur->next)
 939                                 /*
 940                                  * An error was encountered while
 941                                  * picking the last commit; the
 942                                  * sequencer state is useless now --
 943                                  * the user simply needs to resolve
 944                                  * the conflict and commit
 945                                  */
 946                                 remove_sequencer_state(0);
 947                         return res;
 948                 }
 949         }
 950
 951         /*
 952          * Sequence of picks finished successfully; cleanup by
 953          * removing the .git/sequencer directory
 954          */
 955         remove_sequencer_state(1);
 956         return 0;
 957 }
 958
 959 static int pick_revisions(struct replay_opts *opts)
 960 {
 961         struct commit_list *todo_list = NULL;
 962         unsigned char sha1[20];
 963
 964         read_and_refresh_cache(opts);
 965
 966         /*
 967          * Decide what to do depending on the arguments; a fresh
 968          * cherry-pick should be handled differently from an existing
 969          * one that is being continued
 970          */
 971         if (opts->subcommand == REPLAY_REMOVE_STATE) {
 972                 remove_sequencer_state(1);
 973                 return 0;
 974         }
 975         if (opts->subcommand == REPLAY_CONTINUE) {
 976                 if (!file_exists(git_path(SEQ_TODO_FILE)))
 977                         return error(_("No %s in progress"), action_name(opts));
 978                 read_populate_opts(&opts);
 979                 read_populate_todo(&todo_list, opts);
 980
 981                 /* Verify that the conflict has been resolved */
 982                 if (!index_differs_from("HEAD", 0))
 983                         todo_list = todo_list->next;
 984                 return pick_commits(todo_list, opts);
 985         }
 986
 987         /*
 988          * Start a new cherry-pick/ revert sequence; but
 989          * first, make sure that an existing one isn't in
 990          * progress
 991          */
 992
 993         walk_revs_populate_todo(&todo_list, opts);
 994         if (create_seq_dir() < 0) {
 995                 error(_("A cherry-pick or revert is in progress."));
 996                 advise(_("Use --continue to continue the operation"));
 997                 advise(_("or --quit to forget about it"));
 998                 return -1;
 999         }
1000         if (get_sha1("HEAD", sha1)) {
1001                 if (opts->action == REVERT)
1002                         return error(_("Can't revert as initial commit"));
1003                 return error(_("Can't cherry-pick into empty head"));
1004         }
1005         save_head(sha1_to_hex(sha1));
1006         save_opts(opts);
1007         return pick_commits(todo_list, opts);
1008 }
1009
1010 int cmd_revert(int argc, const char **argv, const char *prefix)
1011 {
1012         struct replay_opts opts;
1013         int res;
1014
1015         memset(&opts, 0, sizeof(opts));
1016         if (isatty(0))
1017                 opts.edit = 1;
1018         opts.action = REVERT;
1019         git_config(git_default_config, NULL);
1020         parse_args(argc, argv, &opts);
1021         res = pick_revisions(&opts);
1022         if (res < 0)
1023                 die(_("revert failed"));
1024         return res;
1025 }
1026
1027 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
1028 {
1029         struct replay_opts opts;
1030         int res;
1031
1032         memset(&opts, 0, sizeof(opts));
1033         opts.action = CHERRY_PICK;
1034         git_config(git_default_config, NULL);
1035         parse_args(argc, argv, &opts);
1036         res = pick_revisions(&opts);
1037         if (res < 0)
1038                 die(_("cherry-pick failed"));
1039         return res;
1040 }