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 static int edit, no_replay, no_commit, mainline, signoff, allow_ff;
  39 static enum { REVERT, CHERRY_PICK } action;
  40 static struct commit *commit;
  41 static int commit_argc;
  42 static const char **commit_argv;
  43 static int allow_rerere_auto;
  44
  45 static const char *me;
  46
  47 /* Merge strategy. */
  48 static const char *strategy;
  49 static const char **xopts;
  50 static size_t xopts_nr, xopts_alloc;
  51
  52 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
  53
  54 static char *get_encoding(const char *message);
  55
  56 static const char * const *revert_or_cherry_pick_usage(void)
  57 {
  58         return action == REVERT ? revert_usage : cherry_pick_usage;
  59 }
  60
  61 static int option_parse_x(const struct option *opt,
  62                           const char *arg, int unset)
  63 {
  64         if (unset)
  65                 return 0;
  66
  67         ALLOC_GROW(xopts, xopts_nr + 1, xopts_alloc);
  68         xopts[xopts_nr++] = xstrdup(arg);
  69         return 0;
  70 }
  71
  72 static void parse_args(int argc, const char **argv)
  73 {
  74         const char * const * usage_str = revert_or_cherry_pick_usage();
  75         struct option options[] = {
  76                 OPT_BOOLEAN('n', "no-commit", &no_commit, "don't automatically commit"),
  77                 OPT_BOOLEAN('e', "edit", &edit, "edit the commit message"),
  78                 OPT_NOOP_NOARG('r', NULL),
  79                 OPT_BOOLEAN('s', "signoff", &signoff, "add Signed-off-by:"),
  80                 OPT_INTEGER('m', "mainline", &mainline, "parent number"),
  81                 OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
  82                 OPT_STRING(0, "strategy", &strategy, "strategy", "merge strategy"),
  83                 OPT_CALLBACK('X', "strategy-option", &xopts, "option",
  84                         "option for merge strategy", option_parse_x),
  85                 OPT_END(),
  86                 OPT_END(),
  87                 OPT_END(),
  88         };
  89
  90         if (action == CHERRY_PICK) {
  91                 struct option cp_extra[] = {
  92                         OPT_BOOLEAN('x', NULL, &no_replay, "append commit name"),
  93                         OPT_BOOLEAN(0, "ff", &allow_ff, "allow fast-forward"),
  94                         OPT_END(),
  95                 };
  96                 if (parse_options_concat(options, ARRAY_SIZE(options), cp_extra))
  97                         die(_("program error"));
  98         }
  99
 100         commit_argc = parse_options(argc, argv, NULL, options, usage_str,
 101                                     PARSE_OPT_KEEP_ARGV0 |
 102                                     PARSE_OPT_KEEP_UNKNOWN);
 103         if (commit_argc < 2)
 104                 usage_with_options(usage_str, options);
 105
 106         commit_argv = argv;
 107 }
 108
 109 struct commit_message {
 110         char *parent_label;
 111         const char *label;
 112         const char *subject;
 113         char *reencoded_message;
 114         const char *message;
 115 };
 116
 117 static int get_message(const char *raw_message, struct commit_message *out)
 118 {
 119         const char *encoding;
 120         const char *abbrev, *subject;
 121         int abbrev_len, subject_len;
 122         char *q;
 123
 124         if (!raw_message)
 125                 return -1;
 126         encoding = get_encoding(raw_message);
 127         if (!encoding)
 128                 encoding = "UTF-8";
 129         if (!git_commit_encoding)
 130                 git_commit_encoding = "UTF-8";
 131
 132         out->reencoded_message = NULL;
 133         out->message = raw_message;
 134         if (strcmp(encoding, git_commit_encoding))
 135                 out->reencoded_message = reencode_string(raw_message,
 136                                         git_commit_encoding, encoding);
 137         if (out->reencoded_message)
 138                 out->message = out->reencoded_message;
 139
 140         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
 141         abbrev_len = strlen(abbrev);
 142
 143         subject_len = find_commit_subject(out->message, &subject);
 144
 145         out->parent_label = xmalloc(strlen("parent of ") + abbrev_len +
 146                               strlen("... ") + subject_len + 1);
 147         q = out->parent_label;
 148         q = mempcpy(q, "parent of ", strlen("parent of "));
 149         out->label = q;
 150         q = mempcpy(q, abbrev, abbrev_len);
 151         q = mempcpy(q, "... ", strlen("... "));
 152         out->subject = q;
 153         q = mempcpy(q, subject, subject_len);
 154         *q = '\0';
 155         return 0;
 156 }
 157
 158 static void free_message(struct commit_message *msg)
 159 {
 160         free(msg->parent_label);
 161         free(msg->reencoded_message);
 162 }
 163
 164 static char *get_encoding(const char *message)
 165 {
 166         const char *p = message, *eol;
 167
 168         if (!p)
 169                 die (_("Could not read commit message of %s"),
 170                                 sha1_to_hex(commit->object.sha1));
 171         while (*p && *p != '\n') {
 172                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
 173                         ; /* do nothing */
 174                 if (!prefixcmp(p, "encoding ")) {
 175                         char *result = xmalloc(eol - 8 - p);
 176                         strlcpy(result, p + 9, eol - 8 - p);
 177                         return result;
 178                 }
 179                 p = eol;
 180                 if (*p == '\n')
 181                         p++;
 182         }
 183         return NULL;
 184 }
 185
 186 static void add_message_to_msg(struct strbuf *msgbuf, const char *message)
 187 {
 188         const char *p = message;
 189         while (*p && (*p != '\n' || p[1] != '\n'))
 190                 p++;
 191
 192         if (!*p)
 193                 strbuf_addstr(msgbuf, sha1_to_hex(commit->object.sha1));
 194
 195         p += 2;
 196         strbuf_addstr(msgbuf, p);
 197 }
 198
 199 static void write_cherry_pick_head(void)
 200 {
 201         int fd;
 202         struct strbuf buf = STRBUF_INIT;
 203
 204         strbuf_addf(&buf, "%s\n", sha1_to_hex(commit->object.sha1));
 205
 206         fd = open(git_path("CHERRY_PICK_HEAD"), O_WRONLY | O_CREAT, 0666);
 207         if (fd < 0)
 208                 die_errno(_("Could not open '%s' for writing"),
 209                           git_path("CHERRY_PICK_HEAD"));
 210         if (write_in_full(fd, buf.buf, buf.len) != buf.len || close(fd))
 211                 die_errno(_("Could not write to '%s'"), git_path("CHERRY_PICK_HEAD"));
 212         strbuf_release(&buf);
 213 }
 214
 215 static void advise(const char *advice, ...)
 216 {
 217         va_list params;
 218
 219         va_start(params, advice);
 220         vreportf("hint: ", advice, params);
 221         va_end(params);
 222 }
 223
 224 static void print_advice(void)
 225 {
 226         char *msg = getenv("GIT_CHERRY_PICK_HELP");
 227
 228         if (msg) {
 229                 fprintf(stderr, "%s\n", msg);
 230                 /*
 231                  * A conflict has occured but the porcelain
 232                  * (typically rebase --interactive) wants to take care
 233                  * of the commit itself so remove CHERRY_PICK_HEAD
 234                  */
 235                 unlink(git_path("CHERRY_PICK_HEAD"));
 236                 return;
 237         }
 238
 239         advise("after resolving the conflicts, mark the corrected paths");
 240         advise("with 'git add <paths>' or 'git rm <paths>'");
 241         advise("and commit the result with 'git commit'");
 242 }
 243
 244 static void write_message(struct strbuf *msgbuf, const char *filename)
 245 {
 246         static struct lock_file msg_file;
 247
 248         int msg_fd = hold_lock_file_for_update(&msg_file, filename,
 249                                                LOCK_DIE_ON_ERROR);
 250         if (write_in_full(msg_fd, msgbuf->buf, msgbuf->len) < 0)
 251                 die_errno(_("Could not write to %s."), filename);
 252         strbuf_release(msgbuf);
 253         if (commit_lock_file(&msg_file) < 0)
 254                 die(_("Error wrapping up %s"), filename);
 255 }
 256
 257 static struct tree *empty_tree(void)
 258 {
 259         return lookup_tree((const unsigned char *)EMPTY_TREE_SHA1_BIN);
 260 }
 261
 262 static NORETURN void die_dirty_index(const char *me)
 263 {
 264         if (read_cache_unmerged()) {
 265                 die_resolve_conflict(me);
 266         } else {
 267                 if (advice_commit_before_merge) {
 268                         if (action == REVERT)
 269                                 die(_("Your local changes would be overwritten by revert.\n"
 270                                           "Please, commit your changes or stash them to proceed."));
 271                         else
 272                                 die(_("Your local changes would be overwritten by cherry-pick.\n"
 273                                           "Please, commit your changes or stash them to proceed."));
 274                 } else {
 275                         if (action == REVERT)
 276                                 die(_("Your local changes would be overwritten by revert.\n"));
 277                         else
 278                                 die(_("Your local changes would be overwritten by cherry-pick.\n"));
 279                 }
 280         }
 281 }
 282
 283 static int fast_forward_to(const unsigned char *to, const unsigned char *from)
 284 {
 285         struct ref_lock *ref_lock;
 286
 287         read_cache();
 288         if (checkout_fast_forward(from, to))
 289                 exit(1); /* the callee should have complained already */
 290         ref_lock = lock_any_ref_for_update("HEAD", from, 0);
 291         return write_ref_sha1(ref_lock, to, "cherry-pick");
 292 }
 293
 294 static int do_recursive_merge(struct commit *base, struct commit *next,
 295                               const char *base_label, const char *next_label,
 296                               unsigned char *head, struct strbuf *msgbuf)
 297 {
 298         struct merge_options o;
 299         struct tree *result, *next_tree, *base_tree, *head_tree;
 300         int clean, index_fd;
 301         const char **xopt;
 302         static struct lock_file index_lock;
 303
 304         index_fd = hold_locked_index(&index_lock, 1);
 305
 306         read_cache();
 307
 308         init_merge_options(&o);
 309         o.ancestor = base ? base_label : "(empty tree)";
 310         o.branch1 = "HEAD";
 311         o.branch2 = next ? next_label : "(empty tree)";
 312
 313         head_tree = parse_tree_indirect(head);
 314         next_tree = next ? next->tree : empty_tree();
 315         base_tree = base ? base->tree : empty_tree();
 316
 317         for (xopt = xopts; xopt != xopts + xopts_nr; xopt++)
 318                 parse_merge_opt(&o, *xopt);
 319
 320         clean = merge_trees(&o,
 321                             head_tree,
 322                             next_tree, base_tree, &result);
 323
 324         if (active_cache_changed &&
 325             (write_cache(index_fd, active_cache, active_nr) ||
 326              commit_locked_index(&index_lock)))
 327                 /* TRANSLATORS: %s will be "revert" or "cherry-pick" */
 328                 die(_("%s: Unable to write new index file"), me);
 329         rollback_lock_file(&index_lock);
 330
 331         if (!clean) {
 332                 int i;
 333                 strbuf_addstr(msgbuf, "\nConflicts:\n\n");
 334                 for (i = 0; i < active_nr;) {
 335                         struct cache_entry *ce = active_cache[i++];
 336                         if (ce_stage(ce)) {
 337                                 strbuf_addch(msgbuf, '\t');
 338                                 strbuf_addstr(msgbuf, ce->name);
 339                                 strbuf_addch(msgbuf, '\n');
 340                                 while (i < active_nr && !strcmp(ce->name,
 341                                                 active_cache[i]->name))
 342                                         i++;
 343                         }
 344                 }
 345         }
 346
 347         return !clean;
 348 }
 349
 350 /*
 351  * If we are cherry-pick, and if the merge did not result in
 352  * hand-editing, we will hit this commit and inherit the original
 353  * author date and name.
 354  * If we are revert, or if our cherry-pick results in a hand merge,
 355  * we had better say that the current user is responsible for that.
 356  */
 357 static int run_git_commit(const char *defmsg)
 358 {
 359         /* 6 is max possible length of our args array including NULL */
 360         const char *args[6];
 361         int i = 0;
 362
 363         args[i++] = "commit";
 364         args[i++] = "-n";
 365         if (signoff)
 366                 args[i++] = "-s";
 367         if (!edit) {
 368                 args[i++] = "-F";
 369                 args[i++] = defmsg;
 370         }
 371         args[i] = NULL;
 372
 373         return run_command_v_opt(args, RUN_GIT_CMD);
 374 }
 375
 376 static int do_pick_commit(void)
 377 {
 378         unsigned char head[20];
 379         struct commit *base, *next, *parent;
 380         const char *base_label, *next_label;
 381         struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
 382         char *defmsg = NULL;
 383         struct strbuf msgbuf = STRBUF_INIT;
 384         int res;
 385
 386         if (no_commit) {
 387                 /*
 388                  * We do not intend to commit immediately.  We just want to
 389                  * merge the differences in, so let's compute the tree
 390                  * that represents the "current" state for merge-recursive
 391                  * to work on.
 392                  */
 393                 if (write_cache_as_tree(head, 0, NULL))
 394                         die (_("Your index file is unmerged."));
 395         } else {
 396                 if (get_sha1("HEAD", head))
 397                         die (_("You do not have a valid HEAD"));
 398                 if (index_differs_from("HEAD", 0))
 399                         die_dirty_index(me);
 400         }
 401         discard_cache();
 402
 403         if (!commit->parents) {
 404                 parent = NULL;
 405         }
 406         else if (commit->parents->next) {
 407                 /* Reverting or cherry-picking a merge commit */
 408                 int cnt;
 409                 struct commit_list *p;
 410
 411                 if (!mainline)
 412                         die(_("Commit %s is a merge but no -m option was given."),
 413                             sha1_to_hex(commit->object.sha1));
 414
 415                 for (cnt = 1, p = commit->parents;
 416                      cnt != mainline && p;
 417                      cnt++)
 418                         p = p->next;
 419                 if (cnt != mainline || !p)
 420                         die(_("Commit %s does not have parent %d"),
 421                             sha1_to_hex(commit->object.sha1), mainline);
 422                 parent = p->item;
 423         } else if (0 < mainline)
 424                 die(_("Mainline was specified but commit %s is not a merge."),
 425                     sha1_to_hex(commit->object.sha1));
 426         else
 427                 parent = commit->parents->item;
 428
 429         if (allow_ff && parent && !hashcmp(parent->object.sha1, head))
 430                 return fast_forward_to(commit->object.sha1, head);
 431
 432         if (parent && parse_commit(parent) < 0)
 433                 /* TRANSLATORS: The first %s will be "revert" or
 434                    "cherry-pick", the second %s a SHA1 */
 435                 die(_("%s: cannot parse parent commit %s"),
 436                     me, sha1_to_hex(parent->object.sha1));
 437
 438         if (get_message(commit->buffer, &msg) != 0)
 439                 die(_("Cannot get commit message for %s"),
 440                                 sha1_to_hex(commit->object.sha1));
 441
 442         /*
 443          * "commit" is an existing commit.  We would want to apply
 444          * the difference it introduces since its first parent "prev"
 445          * on top of the current HEAD if we are cherry-pick.  Or the
 446          * reverse of it if we are revert.
 447          */
 448
 449         defmsg = git_pathdup("MERGE_MSG");
 450
 451         if (action == REVERT) {
 452                 base = commit;
 453                 base_label = msg.label;
 454                 next = parent;
 455                 next_label = msg.parent_label;
 456                 strbuf_addstr(&msgbuf, "Revert \"");
 457                 strbuf_addstr(&msgbuf, msg.subject);
 458                 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
 459                 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 460
 461                 if (commit->parents && commit->parents->next) {
 462                         strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
 463                         strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
 464                 }
 465                 strbuf_addstr(&msgbuf, ".\n");
 466         } else {
 467                 base = parent;
 468                 base_label = msg.parent_label;
 469                 next = commit;
 470                 next_label = msg.label;
 471                 add_message_to_msg(&msgbuf, msg.message);
 472                 if (no_replay) {
 473                         strbuf_addstr(&msgbuf, "(cherry picked from commit ");
 474                         strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 475                         strbuf_addstr(&msgbuf, ")\n");
 476                 }
 477                 if (!no_commit)
 478                         write_cherry_pick_head();
 479         }
 480
 481         if (!strategy || !strcmp(strategy, "recursive") || action == REVERT) {
 482                 res = do_recursive_merge(base, next, base_label, next_label,
 483                                          head, &msgbuf);
 484                 write_message(&msgbuf, defmsg);
 485         } else {
 486                 struct commit_list *common = NULL;
 487                 struct commit_list *remotes = NULL;
 488
 489                 write_message(&msgbuf, defmsg);
 490
 491                 commit_list_insert(base, &common);
 492                 commit_list_insert(next, &remotes);
 493                 res = try_merge_command(strategy, xopts_nr, xopts, common,
 494                                         sha1_to_hex(head), remotes);
 495                 free_commit_list(common);
 496                 free_commit_list(remotes);
 497         }
 498
 499         if (res) {
 500                 error(action == REVERT
 501                       ? _("could not revert %s... %s")
 502                       : _("could not apply %s... %s"),
 503                       find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV),
 504                       msg.subject);
 505                 print_advice();
 506                 rerere(allow_rerere_auto);
 507         } else {
 508                 if (!no_commit)
 509                         res = run_git_commit(defmsg);
 510         }
 511
 512         free_message(&msg);
 513         free(defmsg);
 514
 515         return res;
 516 }
 517
 518 static void prepare_revs(struct rev_info *revs)
 519 {
 520         int argc;
 521
 522         init_revisions(revs, NULL);
 523         revs->no_walk = 1;
 524         if (action != REVERT)
 525                 revs->reverse = 1;
 526
 527         argc = setup_revisions(commit_argc, commit_argv, revs, NULL);
 528         if (argc > 1)
 529                 usage(*revert_or_cherry_pick_usage());
 530
 531         if (prepare_revision_walk(revs))
 532                 die(_("revision walk setup failed"));
 533
 534         if (!revs->commits)
 535                 die(_("empty commit set passed"));
 536 }
 537
 538 static void read_and_refresh_cache(const char *me)
 539 {
 540         static struct lock_file index_lock;
 541         int index_fd = hold_locked_index(&index_lock, 0);
 542         if (read_index_preload(&the_index, NULL) < 0)
 543                 die(_("git %s: failed to read the index"), me);
 544         refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
 545         if (the_index.cache_changed) {
 546                 if (write_index(&the_index, index_fd) ||
 547                     commit_locked_index(&index_lock))
 548                         die(_("git %s: failed to refresh the index"), me);
 549         }
 550         rollback_lock_file(&index_lock);
 551 }
 552
 553 static int revert_or_cherry_pick(int argc, const char **argv)
 554 {
 555         struct rev_info revs;
 556
 557         git_config(git_default_config, NULL);
 558         me = action == REVERT ? "revert" : "cherry-pick";
 559         setenv(GIT_REFLOG_ACTION, me, 0);
 560         parse_args(argc, argv);
 561
 562         if (allow_ff) {
 563                 if (signoff)
 564                         die(_("cherry-pick --ff cannot be used with --signoff"));
 565                 if (no_commit)
 566                         die(_("cherry-pick --ff cannot be used with --no-commit"));
 567                 if (no_replay)
 568                         die(_("cherry-pick --ff cannot be used with -x"));
 569                 if (edit)
 570                         die(_("cherry-pick --ff cannot be used with --edit"));
 571         }
 572
 573         read_and_refresh_cache(me);
 574
 575         prepare_revs(&revs);
 576
 577         while ((commit = get_revision(&revs))) {
 578                 int res = do_pick_commit();
 579                 if (res)
 580                         return res;
 581         }
 582
 583         return 0;
 584 }
 585
 586 int cmd_revert(int argc, const char **argv, const char *prefix)
 587 {
 588         if (isatty(0))
 589                 edit = 1;
 590         action = REVERT;
 591         return revert_or_cherry_pick(argc, argv);
 592 }
 593
 594 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
 595 {
 596         action = CHERRY_PICK;
 597         return revert_or_cherry_pick(argc, argv);
 598 }