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
  17 /*
  18  * This implements the builtins revert and cherry-pick.
  19  *
  20  * Copyright (c) 2007 Johannes E. Schindelin
  21  *
  22  * Based on git-revert.sh, which is
  23  *
  24  * Copyright (c) 2005 Linus Torvalds
  25  * Copyright (c) 2005 Junio C Hamano
  26  */
  27
  28 static const char * const revert_usage[] = {
  29         "git revert [options] <commit-ish>",
  30         NULL
  31 };
  32
  33 static const char * const cherry_pick_usage[] = {
  34         "git cherry-pick [options] <commit-ish>",
  35         NULL
  36 };
  37
  38 enum replay_action { REVERT, CHERRY_PICK };
  39
  40 struct replay_opts {
  41         enum replay_action action;
  42
  43         /* Boolean options */
  44         int edit;
  45         int record_origin;
  46         int no_commit;
  47         int signoff;
  48         int allow_ff;
  49         int allow_rerere_auto;
  50
  51         int mainline;
  52         int commit_argc;
  53         const char **commit_argv;
  54
  55         /* Merge strategy */
  56         const char *strategy;
  57         const char **xopts;
  58         size_t xopts_nr, xopts_alloc;
  59 };
  60
  61 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
  62
  63 static const char *action_name(const struct replay_opts *opts)
  64 {
  65         return opts->action == REVERT ? "revert" : "cherry-pick";
  66 }
  67
  68 static char *get_encoding(const char *message);
  69
  70 static const char * const *revert_or_cherry_pick_usage(struct replay_opts *opts)
  71 {
  72         return opts->action == REVERT ? revert_usage : cherry_pick_usage;
  73 }
  74
  75 static int option_parse_x(const struct option *opt,
  76                           const char *arg, int unset)
  77 {
  78         struct replay_opts **opts_ptr = opt->value;
  79         struct replay_opts *opts = *opts_ptr;
  80
  81         if (unset)
  82                 return 0;
  83
  84         ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
  85         opts->xopts[opts->xopts_nr++] = xstrdup(arg);
  86         return 0;
  87 }
  88
  89 static void verify_opt_compatible(const char *me, const char *base_opt, ...)
  90 {
  91         const char *this_opt;
  92         va_list ap;
  93
  94         va_start(ap, base_opt);
  95         while ((this_opt = va_arg(ap, const char *))) {
  96                 if (va_arg(ap, int))
  97                         break;
  98         }
  99         va_end(ap);
 100
 101         if (this_opt)
 102                 die(_("%s: %s cannot be used with %s"), me, this_opt, base_opt);
 103 }
 104
 105 static void parse_args(int argc, const char **argv, struct replay_opts *opts)
 106 {
 107         const char * const * usage_str = revert_or_cherry_pick_usage(opts);
 108         const char *me = action_name(opts);
 109         int noop;
 110         struct option options[] = {
 111                 OPT_BOOLEAN('n', "no-commit", &opts->no_commit, "don't automatically commit"),
 112                 OPT_BOOLEAN('e', "edit", &opts->edit, "edit the commit message"),
 113                 { OPTION_BOOLEAN, 'r', NULL, &noop, NULL, "no-op (backward compatibility)",
 114                   PARSE_OPT_NOARG | PARSE_OPT_HIDDEN, NULL, 0 },
 115                 OPT_BOOLEAN('s', "signoff", &opts->signoff, "add Signed-off-by:"),
 116                 OPT_INTEGER('m', "mainline", &opts->mainline, "parent number"),
 117                 OPT_RERERE_AUTOUPDATE(&opts->allow_rerere_auto),
 118                 OPT_STRING(0, "strategy", &opts->strategy, "strategy", "merge strategy"),
 119                 OPT_CALLBACK('X', "strategy-option", &opts, "option",
 120                         "option for merge strategy", option_parse_x),
 121                 OPT_END(),
 122                 OPT_END(),
 123                 OPT_END(),
 124         };
 125
 126         if (opts->action == CHERRY_PICK) {
 127                 struct option cp_extra[] = {
 128                         OPT_BOOLEAN('x', NULL, &opts->record_origin, "append commit name"),
 129                         OPT_BOOLEAN(0, "ff", &opts->allow_ff, "allow fast-forward"),
 130                         OPT_END(),
 131                 };
 132                 if (parse_options_concat(options, ARRAY_SIZE(options), cp_extra))
 133                         die(_("program error"));
 134         }
 135
 136         opts->commit_argc = parse_options(argc, argv, NULL, options, usage_str,
 137                                         PARSE_OPT_KEEP_ARGV0 |
 138                                         PARSE_OPT_KEEP_UNKNOWN);
 139         if (opts->commit_argc < 2)
 140                 usage_with_options(usage_str, options);
 141
 142         if (opts->allow_ff)
 143                 verify_opt_compatible(me, "--ff",
 144                                 "--signoff", opts->signoff,
 145                                 "--no-commit", opts->no_commit,
 146                                 "-x", opts->record_origin,
 147                                 "--edit", opts->edit,
 148                                 NULL);
 149         opts->commit_argv = argv;
 150 }
 151
 152 struct commit_message {
 153         char *parent_label;
 154         const char *label;
 155         const char *subject;
 156         char *reencoded_message;
 157         const char *message;
 158 };
 159
 160 static int get_message(struct commit *commit, struct commit_message *out)
 161 {
 162         const char *encoding;
 163         const char *abbrev, *subject;
 164         int abbrev_len, subject_len;
 165         char *q;
 166
 167         if (!commit->buffer)
 168                 return -1;
 169         encoding = get_encoding(commit->buffer);
 170         if (!encoding)
 171                 encoding = "UTF-8";
 172         if (!git_commit_encoding)
 173                 git_commit_encoding = "UTF-8";
 174
 175         out->reencoded_message = NULL;
 176         out->message = commit->buffer;
 177         if (strcmp(encoding, git_commit_encoding))
 178                 out->reencoded_message = reencode_string(commit->buffer,
 179                                         git_commit_encoding, encoding);
 180         if (out->reencoded_message)
 181                 out->message = out->reencoded_message;
 182
 183         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
 184         abbrev_len = strlen(abbrev);
 185
 186         subject_len = find_commit_subject(out->message, &subject);
 187
 188         out->parent_label = xmalloc(strlen("parent of ") + abbrev_len +
 189                               strlen("... ") + subject_len + 1);
 190         q = out->parent_label;
 191         q = mempcpy(q, "parent of ", strlen("parent of "));
 192         out->label = q;
 193         q = mempcpy(q, abbrev, abbrev_len);
 194         q = mempcpy(q, "... ", strlen("... "));
 195         out->subject = q;
 196         q = mempcpy(q, subject, subject_len);
 197         *q = '\0';
 198         return 0;
 199 }
 200
 201 static void free_message(struct commit_message *msg)
 202 {
 203         free(msg->parent_label);
 204         free(msg->reencoded_message);
 205 }
 206
 207 static char *get_encoding(const char *message)
 208 {
 209         const char *p = message, *eol;
 210
 211         while (*p && *p != '\n') {
 212                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
 213                         ; /* do nothing */
 214                 if (!prefixcmp(p, "encoding ")) {
 215                         char *result = xmalloc(eol - 8 - p);
 216                         strlcpy(result, p + 9, eol - 8 - p);
 217                         return result;
 218                 }
 219                 p = eol;
 220                 if (*p == '\n')
 221                         p++;
 222         }
 223         return NULL;
 224 }
 225
 226 static void write_cherry_pick_head(struct commit *commit)
 227 {
 228         int fd;
 229         struct strbuf buf = STRBUF_INIT;
 230
 231         strbuf_addf(&buf, "%s\n", sha1_to_hex(commit->object.sha1));
 232
 233         fd = open(git_path("CHERRY_PICK_HEAD"), O_WRONLY | O_CREAT, 0666);
 234         if (fd < 0)
 235                 die_errno(_("Could not open '%s' for writing"),
 236                           git_path("CHERRY_PICK_HEAD"));
 237         if (write_in_full(fd, buf.buf, buf.len) != buf.len || close(fd))
 238                 die_errno(_("Could not write to '%s'"), git_path("CHERRY_PICK_HEAD"));
 239         strbuf_release(&buf);
 240 }
 241
 242 static void print_advice(void)
 243 {
 244         char *msg = getenv("GIT_CHERRY_PICK_HELP");
 245
 246         if (msg) {
 247                 fprintf(stderr, "%s\n", msg);
 248                 /*
 249                  * A conflict has occured but the porcelain
 250                  * (typically rebase --interactive) wants to take care
 251                  * of the commit itself so remove CHERRY_PICK_HEAD
 252                  */
 253                 unlink(git_path("CHERRY_PICK_HEAD"));
 254                 return;
 255         }
 256
 257         advise("after resolving the conflicts, mark the corrected paths");
 258         advise("with 'git add <paths>' or 'git rm <paths>'");
 259         advise("and commit the result with 'git commit'");
 260 }
 261
 262 static void write_message(struct strbuf *msgbuf, const char *filename)
 263 {
 264         static struct lock_file msg_file;
 265
 266         int msg_fd = hold_lock_file_for_update(&msg_file, filename,
 267                                                LOCK_DIE_ON_ERROR);
 268         if (write_in_full(msg_fd, msgbuf->buf, msgbuf->len) < 0)
 269                 die_errno(_("Could not write to %s."), filename);
 270         strbuf_release(msgbuf);
 271         if (commit_lock_file(&msg_file) < 0)
 272                 die(_("Error wrapping up %s"), filename);
 273 }
 274
 275 static struct tree *empty_tree(void)
 276 {
 277         struct tree *tree = xcalloc(1, sizeof(struct tree));
 278
 279         tree->object.parsed = 1;
 280         tree->object.type = OBJ_TREE;
 281         pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
 282         return tree;
 283 }
 284
 285 static NORETURN void die_dirty_index(struct replay_opts *opts)
 286 {
 287         if (read_cache_unmerged()) {
 288                 die_resolve_conflict(action_name(opts));
 289         } else {
 290                 if (advice_commit_before_merge) {
 291                         if (opts->action == REVERT)
 292                                 die(_("Your local changes would be overwritten by revert.\n"
 293                                           "Please, commit your changes or stash them to proceed."));
 294                         else
 295                                 die(_("Your local changes would be overwritten by cherry-pick.\n"
 296                                           "Please, commit your changes or stash them to proceed."));
 297                 } else {
 298                         if (opts->action == REVERT)
 299                                 die(_("Your local changes would be overwritten by revert.\n"));
 300                         else
 301                                 die(_("Your local changes would be overwritten by cherry-pick.\n"));
 302                 }
 303         }
 304 }
 305
 306 static int fast_forward_to(const unsigned char *to, const unsigned char *from)
 307 {
 308         struct ref_lock *ref_lock;
 309
 310         read_cache();
 311         if (checkout_fast_forward(from, to))
 312                 exit(1); /* the callee should have complained already */
 313         ref_lock = lock_any_ref_for_update("HEAD", from, 0);
 314         return write_ref_sha1(ref_lock, to, "cherry-pick");
 315 }
 316
 317 static int do_recursive_merge(struct commit *base, struct commit *next,
 318                               const char *base_label, const char *next_label,
 319                               unsigned char *head, struct strbuf *msgbuf,
 320                               struct replay_opts *opts)
 321 {
 322         struct merge_options o;
 323         struct tree *result, *next_tree, *base_tree, *head_tree;
 324         int clean, index_fd;
 325         const char **xopt;
 326         static struct lock_file index_lock;
 327
 328         index_fd = hold_locked_index(&index_lock, 1);
 329
 330         read_cache();
 331
 332         init_merge_options(&o);
 333         o.ancestor = base ? base_label : "(empty tree)";
 334         o.branch1 = "HEAD";
 335         o.branch2 = next ? next_label : "(empty tree)";
 336
 337         head_tree = parse_tree_indirect(head);
 338         next_tree = next ? next->tree : empty_tree();
 339         base_tree = base ? base->tree : empty_tree();
 340
 341         for (xopt = opts->xopts; xopt != opts->xopts + opts->xopts_nr; xopt++)
 342                 parse_merge_opt(&o, *xopt);
 343
 344         clean = merge_trees(&o,
 345                             head_tree,
 346                             next_tree, base_tree, &result);
 347
 348         if (active_cache_changed &&
 349             (write_cache(index_fd, active_cache, active_nr) ||
 350              commit_locked_index(&index_lock)))
 351                 /* TRANSLATORS: %s will be "revert" or "cherry-pick" */
 352                 die(_("%s: Unable to write new index file"), action_name(opts));
 353         rollback_lock_file(&index_lock);
 354
 355         if (!clean) {
 356                 int i;
 357                 strbuf_addstr(msgbuf, "\nConflicts:\n\n");
 358                 for (i = 0; i < active_nr;) {
 359                         struct cache_entry *ce = active_cache[i++];
 360                         if (ce_stage(ce)) {
 361                                 strbuf_addch(msgbuf, '\t');
 362                                 strbuf_addstr(msgbuf, ce->name);
 363                                 strbuf_addch(msgbuf, '\n');
 364                                 while (i < active_nr && !strcmp(ce->name,
 365                                                 active_cache[i]->name))
 366                                         i++;
 367                         }
 368                 }
 369         }
 370
 371         return !clean;
 372 }
 373
 374 /*
 375  * If we are cherry-pick, and if the merge did not result in
 376  * hand-editing, we will hit this commit and inherit the original
 377  * author date and name.
 378  * If we are revert, or if our cherry-pick results in a hand merge,
 379  * we had better say that the current user is responsible for that.
 380  */
 381 static int run_git_commit(const char *defmsg, struct replay_opts *opts)
 382 {
 383         /* 6 is max possible length of our args array including NULL */
 384         const char *args[6];
 385         int i = 0;
 386
 387         args[i++] = "commit";
 388         args[i++] = "-n";
 389         if (opts->signoff)
 390                 args[i++] = "-s";
 391         if (!opts->edit) {
 392                 args[i++] = "-F";
 393                 args[i++] = defmsg;
 394         }
 395         args[i] = NULL;
 396
 397         return run_command_v_opt(args, RUN_GIT_CMD);
 398 }
 399
 400 static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
 401 {
 402         unsigned char head[20];
 403         struct commit *base, *next, *parent;
 404         const char *base_label, *next_label;
 405         struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
 406         char *defmsg = NULL;
 407         struct strbuf msgbuf = STRBUF_INIT;
 408         int res;
 409
 410         if (opts->no_commit) {
 411                 /*
 412                  * We do not intend to commit immediately.  We just want to
 413                  * merge the differences in, so let's compute the tree
 414                  * that represents the "current" state for merge-recursive
 415                  * to work on.
 416                  */
 417                 if (write_cache_as_tree(head, 0, NULL))
 418                         die (_("Your index file is unmerged."));
 419         } else {
 420                 if (get_sha1("HEAD", head))
 421                         die (_("You do not have a valid HEAD"));
 422                 if (index_differs_from("HEAD", 0))
 423                         die_dirty_index(opts);
 424         }
 425         discard_cache();
 426
 427         if (!commit->parents) {
 428                 parent = NULL;
 429         }
 430         else if (commit->parents->next) {
 431                 /* Reverting or cherry-picking a merge commit */
 432                 int cnt;
 433                 struct commit_list *p;
 434
 435                 if (!opts->mainline)
 436                         die(_("Commit %s is a merge but no -m option was given."),
 437                             sha1_to_hex(commit->object.sha1));
 438
 439                 for (cnt = 1, p = commit->parents;
 440                      cnt != opts->mainline && p;
 441                      cnt++)
 442                         p = p->next;
 443                 if (cnt != opts->mainline || !p)
 444                         die(_("Commit %s does not have parent %d"),
 445                             sha1_to_hex(commit->object.sha1), opts->mainline);
 446                 parent = p->item;
 447         } else if (0 < opts->mainline)
 448                 die(_("Mainline was specified but commit %s is not a merge."),
 449                     sha1_to_hex(commit->object.sha1));
 450         else
 451                 parent = commit->parents->item;
 452
 453         if (opts->allow_ff && parent && !hashcmp(parent->object.sha1, head))
 454                 return fast_forward_to(commit->object.sha1, head);
 455
 456         if (parent && parse_commit(parent) < 0)
 457                 /* TRANSLATORS: The first %s will be "revert" or
 458                    "cherry-pick", the second %s a SHA1 */
 459                 die(_("%s: cannot parse parent commit %s"),
 460                     action_name(opts), sha1_to_hex(parent->object.sha1));
 461
 462         if (get_message(commit, &msg) != 0)
 463                 die(_("Cannot get commit message for %s"),
 464                                 sha1_to_hex(commit->object.sha1));
 465
 466         /*
 467          * "commit" is an existing commit.  We would want to apply
 468          * the difference it introduces since its first parent "prev"
 469          * on top of the current HEAD if we are cherry-pick.  Or the
 470          * reverse of it if we are revert.
 471          */
 472
 473         defmsg = git_pathdup("MERGE_MSG");
 474
 475         if (opts->action == REVERT) {
 476                 base = commit;
 477                 base_label = msg.label;
 478                 next = parent;
 479                 next_label = msg.parent_label;
 480                 strbuf_addstr(&msgbuf, "Revert \"");
 481                 strbuf_addstr(&msgbuf, msg.subject);
 482                 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
 483                 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 484
 485                 if (commit->parents && commit->parents->next) {
 486                         strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
 487                         strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
 488                 }
 489                 strbuf_addstr(&msgbuf, ".\n");
 490         } else {
 491                 const char *p;
 492
 493                 base = parent;
 494                 base_label = msg.parent_label;
 495                 next = commit;
 496                 next_label = msg.label;
 497
 498                 /*
 499                  * Append the commit log message to msgbuf; it starts
 500                  * after the tree, parent, author, committer
 501                  * information followed by "\n\n".
 502                  */
 503                 p = strstr(msg.message, "\n\n");
 504                 if (p) {
 505                         p += 2;
 506                         strbuf_addstr(&msgbuf, p);
 507                 }
 508
 509                 if (opts->record_origin) {
 510                         strbuf_addstr(&msgbuf, "(cherry picked from commit ");
 511                         strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 512                         strbuf_addstr(&msgbuf, ")\n");
 513                 }
 514                 if (!opts->no_commit)
 515                         write_cherry_pick_head(commit);
 516         }
 517
 518         if (!opts->strategy || !strcmp(opts->strategy, "recursive") || opts->action == REVERT) {
 519                 res = do_recursive_merge(base, next, base_label, next_label,
 520                                          head, &msgbuf, opts);
 521                 write_message(&msgbuf, defmsg);
 522         } else {
 523                 struct commit_list *common = NULL;
 524                 struct commit_list *remotes = NULL;
 525
 526                 write_message(&msgbuf, defmsg);
 527
 528                 commit_list_insert(base, &common);
 529                 commit_list_insert(next, &remotes);
 530                 res = try_merge_command(opts->strategy, opts->xopts_nr, opts->xopts,
 531                                         common, sha1_to_hex(head), remotes);
 532                 free_commit_list(common);
 533                 free_commit_list(remotes);
 534         }
 535
 536         if (res) {
 537                 error(opts->action == REVERT
 538                       ? _("could not revert %s... %s")
 539                       : _("could not apply %s... %s"),
 540                       find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV),
 541                       msg.subject);
 542                 print_advice();
 543                 rerere(opts->allow_rerere_auto);
 544         } else {
 545                 if (!opts->no_commit)
 546                         res = run_git_commit(defmsg, opts);
 547         }
 548
 549         free_message(&msg);
 550         free(defmsg);
 551
 552         return res;
 553 }
 554
 555 static void prepare_revs(struct rev_info *revs, struct replay_opts *opts)
 556 {
 557         int argc;
 558
 559         init_revisions(revs, NULL);
 560         revs->no_walk = 1;
 561         if (opts->action != REVERT)
 562                 revs->reverse = 1;
 563
 564         argc = setup_revisions(opts->commit_argc, opts->commit_argv, revs, NULL);
 565         if (argc > 1)
 566                 usage(*revert_or_cherry_pick_usage(opts));
 567
 568         if (prepare_revision_walk(revs))
 569                 die(_("revision walk setup failed"));
 570
 571         if (!revs->commits)
 572                 die(_("empty commit set passed"));
 573 }
 574
 575 static void read_and_refresh_cache(struct replay_opts *opts)
 576 {
 577         static struct lock_file index_lock;
 578         int index_fd = hold_locked_index(&index_lock, 0);
 579         if (read_index_preload(&the_index, NULL) < 0)
 580                 die(_("git %s: failed to read the index"), action_name(opts));
 581         refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
 582         if (the_index.cache_changed) {
 583                 if (write_index(&the_index, index_fd) ||
 584                     commit_locked_index(&index_lock))
 585                         die(_("git %s: failed to refresh the index"), action_name(opts));
 586         }
 587         rollback_lock_file(&index_lock);
 588 }
 589
 590 static int pick_commits(struct replay_opts *opts)
 591 {
 592         struct rev_info revs;
 593         struct commit *commit;
 594
 595         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
 596         if (opts->allow_ff)
 597                 assert(!(opts->signoff || opts->no_commit ||
 598                                 opts->record_origin || opts->edit));
 599         read_and_refresh_cache(opts);
 600
 601         prepare_revs(&revs, opts);
 602
 603         while ((commit = get_revision(&revs))) {
 604                 int res = do_pick_commit(commit, opts);
 605                 if (res)
 606                         return res;
 607         }
 608
 609         return 0;
 610 }
 611
 612 int cmd_revert(int argc, const char **argv, const char *prefix)
 613 {
 614         struct replay_opts opts;
 615
 616         memset(&opts, 0, sizeof(opts));
 617         if (isatty(0))
 618                 opts.edit = 1;
 619         opts.action = REVERT;
 620         git_config(git_default_config, NULL);
 621         parse_args(argc, argv, &opts);
 622         return pick_commits(&opts);
 623 }
 624
 625 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
 626 {
 627         struct replay_opts opts;
 628
 629         memset(&opts, 0, sizeof(opts));
 630         opts.action = CHERRY_PICK;
 631         git_config(git_default_config, NULL);
 632         parse_args(argc, argv, &opts);
 633         return pick_commits(&opts);
 634 }