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 "wt-status.h"
   7 #include "run-command.h"
   8 #include "exec_cmd.h"
   9 #include "utf8.h"
  10 #include "parse-options.h"
  11 #include "cache-tree.h"
  12 #include "diff.h"
  13 #include "revision.h"
  14 #include "rerere.h"
  15 #include "merge-recursive.h"
  16 #include "refs.h"
  17
  18 /*
  19  * This implements the builtins revert and cherry-pick.
  20  *
  21  * Copyright (c) 2007 Johannes E. Schindelin
  22  *
  23  * Based on git-revert.sh, which is
  24  *
  25  * Copyright (c) 2005 Linus Torvalds
  26  * Copyright (c) 2005 Junio C Hamano
  27  */
  28
  29 static const char * const revert_usage[] = {
  30         "git revert [options] <commit-ish>",
  31         NULL
  32 };
  33
  34 static const char * const cherry_pick_usage[] = {
  35         "git cherry-pick [options] <commit-ish>",
  36         NULL
  37 };
  38
  39 static int edit, no_replay, no_commit, mainline, signoff, allow_ff;
  40 static enum { REVERT, CHERRY_PICK } action;
  41 static struct commit *commit;
  42 static int commit_argc;
  43 static const char **commit_argv;
  44 static int allow_rerere_auto;
  45
  46 static const char *me;
  47 static const char *strategy;
  48
  49 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
  50
  51 static char *get_encoding(const char *message);
  52
  53 static const char * const *revert_or_cherry_pick_usage(void)
  54 {
  55         return action == REVERT ? revert_usage : cherry_pick_usage;
  56 }
  57
  58 static void parse_args(int argc, const char **argv)
  59 {
  60         const char * const * usage_str = revert_or_cherry_pick_usage();
  61         int noop;
  62         struct option options[] = {
  63                 OPT_BOOLEAN('n', "no-commit", &no_commit, "don't automatically commit"),
  64                 OPT_BOOLEAN('e', "edit", &edit, "edit the commit message"),
  65                 OPT_BOOLEAN('r', NULL, &noop, "no-op (backward compatibility)"),
  66                 OPT_BOOLEAN('s', "signoff", &signoff, "add Signed-off-by:"),
  67                 OPT_INTEGER('m', "mainline", &mainline, "parent number"),
  68                 OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
  69                 OPT_STRING(0, "strategy", &strategy, "strategy", "merge strategy"),
  70                 OPT_END(),
  71                 OPT_END(),
  72                 OPT_END(),
  73         };
  74
  75         if (action == CHERRY_PICK) {
  76                 struct option cp_extra[] = {
  77                         OPT_BOOLEAN('x', NULL, &no_replay, "append commit name"),
  78                         OPT_BOOLEAN(0, "ff", &allow_ff, "allow fast-forward"),
  79                         OPT_END(),
  80                 };
  81                 if (parse_options_concat(options, ARRAY_SIZE(options), cp_extra))
  82                         die("program error");
  83         }
  84
  85         commit_argc = parse_options(argc, argv, NULL, options, usage_str,
  86                                     PARSE_OPT_KEEP_ARGV0 |
  87                                     PARSE_OPT_KEEP_UNKNOWN);
  88         if (commit_argc < 2)
  89                 usage_with_options(usage_str, options);
  90
  91         commit_argv = argv;
  92 }
  93
  94 struct commit_message {
  95         char *parent_label;
  96         const char *label;
  97         const char *subject;
  98         char *reencoded_message;
  99         const char *message;
 100 };
 101
 102 static int get_message(const char *raw_message, struct commit_message *out)
 103 {
 104         const char *encoding;
 105         const char *p, *abbrev, *eol;
 106         char *q;
 107         int abbrev_len, oneline_len;
 108
 109         if (!raw_message)
 110                 return -1;
 111         encoding = get_encoding(raw_message);
 112         if (!encoding)
 113                 encoding = "UTF-8";
 114         if (!git_commit_encoding)
 115                 git_commit_encoding = "UTF-8";
 116
 117         out->reencoded_message = NULL;
 118         out->message = raw_message;
 119         if (strcmp(encoding, git_commit_encoding))
 120                 out->reencoded_message = reencode_string(raw_message,
 121                                         git_commit_encoding, encoding);
 122         if (out->reencoded_message)
 123                 out->message = out->reencoded_message;
 124
 125         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
 126         abbrev_len = strlen(abbrev);
 127
 128         /* Find beginning and end of commit subject. */
 129         p = out->message;
 130         while (*p && (*p != '\n' || p[1] != '\n'))
 131                 p++;
 132         if (*p) {
 133                 p += 2;
 134                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
 135                         ; /* do nothing */
 136         } else
 137                 eol = p;
 138         oneline_len = eol - p;
 139
 140         out->parent_label = xmalloc(strlen("parent of ") + abbrev_len +
 141                               strlen("... ") + oneline_len + 1);
 142         q = out->parent_label;
 143         q = mempcpy(q, "parent of ", strlen("parent of "));
 144         out->label = q;
 145         q = mempcpy(q, abbrev, abbrev_len);
 146         q = mempcpy(q, "... ", strlen("... "));
 147         out->subject = q;
 148         q = mempcpy(q, p, oneline_len);
 149         *q = '\0';
 150         return 0;
 151 }
 152
 153 static void free_message(struct commit_message *msg)
 154 {
 155         free(msg->parent_label);
 156         free(msg->reencoded_message);
 157 }
 158
 159 static char *get_encoding(const char *message)
 160 {
 161         const char *p = message, *eol;
 162
 163         if (!p)
 164                 die ("Could not read commit message of %s",
 165                                 sha1_to_hex(commit->object.sha1));
 166         while (*p && *p != '\n') {
 167                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
 168                         ; /* do nothing */
 169                 if (!prefixcmp(p, "encoding ")) {
 170                         char *result = xmalloc(eol - 8 - p);
 171                         strlcpy(result, p + 9, eol - 8 - p);
 172                         return result;
 173                 }
 174                 p = eol;
 175                 if (*p == '\n')
 176                         p++;
 177         }
 178         return NULL;
 179 }
 180
 181 static void add_message_to_msg(struct strbuf *msgbuf, const char *message)
 182 {
 183         const char *p = message;
 184         while (*p && (*p != '\n' || p[1] != '\n'))
 185                 p++;
 186
 187         if (!*p)
 188                 strbuf_addstr(msgbuf, sha1_to_hex(commit->object.sha1));
 189
 190         p += 2;
 191         strbuf_addstr(msgbuf, p);
 192 }
 193
 194 static void set_author_ident_env(const char *message)
 195 {
 196         const char *p = message;
 197         if (!p)
 198                 die ("Could not read commit message of %s",
 199                                 sha1_to_hex(commit->object.sha1));
 200         while (*p && *p != '\n') {
 201                 const char *eol;
 202
 203                 for (eol = p; *eol && *eol != '\n'; eol++)
 204                         ; /* do nothing */
 205                 if (!prefixcmp(p, "author ")) {
 206                         char *line, *pend, *email, *timestamp;
 207
 208                         p += 7;
 209                         line = xmemdupz(p, eol - p);
 210                         email = strchr(line, '<');
 211                         if (!email)
 212                                 die ("Could not extract author email from %s",
 213                                         sha1_to_hex(commit->object.sha1));
 214                         if (email == line)
 215                                 pend = line;
 216                         else
 217                                 for (pend = email; pend != line + 1 &&
 218                                                 isspace(pend[-1]); pend--);
 219                                         ; /* do nothing */
 220                         *pend = '\0';
 221                         email++;
 222                         timestamp = strchr(email, '>');
 223                         if (!timestamp)
 224                                 die ("Could not extract author time from %s",
 225                                         sha1_to_hex(commit->object.sha1));
 226                         *timestamp = '\0';
 227                         for (timestamp++; *timestamp && isspace(*timestamp);
 228                                         timestamp++)
 229                                 ; /* do nothing */
 230                         setenv("GIT_AUTHOR_NAME", line, 1);
 231                         setenv("GIT_AUTHOR_EMAIL", email, 1);
 232                         setenv("GIT_AUTHOR_DATE", timestamp, 1);
 233                         free(line);
 234                         return;
 235                 }
 236                 p = eol;
 237                 if (*p == '\n')
 238                         p++;
 239         }
 240         die ("No author information found in %s",
 241                         sha1_to_hex(commit->object.sha1));
 242 }
 243
 244 static char *help_msg(void)
 245 {
 246         struct strbuf helpbuf = STRBUF_INIT;
 247         char *msg = getenv("GIT_CHERRY_PICK_HELP");
 248
 249         if (msg)
 250                 return msg;
 251
 252         strbuf_addstr(&helpbuf, "  After resolving the conflicts,\n"
 253                 "mark the corrected paths with 'git add <paths>' or 'git rm <paths>'\n"
 254                 "and commit the result");
 255
 256         if (action == CHERRY_PICK) {
 257                 strbuf_addf(&helpbuf, " with: \n"
 258                         "\n"
 259                         "        git commit -c %s\n",
 260                             sha1_to_hex(commit->object.sha1));
 261         }
 262         else
 263                 strbuf_addch(&helpbuf, '.');
 264         return strbuf_detach(&helpbuf, NULL);
 265 }
 266
 267 static void write_message(struct strbuf *msgbuf, const char *filename)
 268 {
 269         static struct lock_file msg_file;
 270
 271         int msg_fd = hold_lock_file_for_update(&msg_file, filename,
 272                                                LOCK_DIE_ON_ERROR);
 273         if (write_in_full(msg_fd, msgbuf->buf, msgbuf->len) < 0)
 274                 die_errno("Could not write to %s.", filename);
 275         strbuf_release(msgbuf);
 276         if (commit_lock_file(&msg_file) < 0)
 277                 die("Error wrapping up %s", filename);
 278 }
 279
 280 static struct tree *empty_tree(void)
 281 {
 282         struct tree *tree = xcalloc(1, sizeof(struct tree));
 283
 284         tree->object.parsed = 1;
 285         tree->object.type = OBJ_TREE;
 286         pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
 287         return tree;
 288 }
 289
 290 static NORETURN void die_dirty_index(const char *me)
 291 {
 292         if (read_cache_unmerged()) {
 293                 die_resolve_conflict(me);
 294         } else {
 295                 if (advice_commit_before_merge)
 296                         die("Your local changes would be overwritten by %s.\n"
 297                             "Please, commit your changes or stash them to proceed.", me);
 298                 else
 299                         die("Your local changes would be overwritten by %s.\n", me);
 300         }
 301 }
 302
 303 static int fast_forward_to(const unsigned char *to, const unsigned char *from)
 304 {
 305         struct ref_lock *ref_lock;
 306
 307         read_cache();
 308         if (checkout_fast_forward(from, to))
 309                 exit(1); /* the callee should have complained already */
 310         ref_lock = lock_any_ref_for_update("HEAD", from, 0);
 311         return write_ref_sha1(ref_lock, to, "cherry-pick");
 312 }
 313
 314 static void do_recursive_merge(struct commit *base, struct commit *next,
 315                                const char *base_label, const char *next_label,
 316                                unsigned char *head, struct strbuf *msgbuf,
 317                                char *defmsg)
 318 {
 319         struct merge_options o;
 320         struct tree *result, *next_tree, *base_tree, *head_tree;
 321         int clean, index_fd;
 322         static struct lock_file index_lock;
 323
 324         index_fd = hold_locked_index(&index_lock, 1);
 325
 326         read_cache();
 327         init_merge_options(&o);
 328         o.ancestor = base ? base_label : "(empty tree)";
 329         o.branch1 = "HEAD";
 330         o.branch2 = next ? next_label : "(empty tree)";
 331
 332         head_tree = parse_tree_indirect(head);
 333         next_tree = next ? next->tree : empty_tree();
 334         base_tree = base ? base->tree : empty_tree();
 335
 336         clean = merge_trees(&o,
 337                             head_tree,
 338                             next_tree, base_tree, &result);
 339
 340         if (active_cache_changed &&
 341             (write_cache(index_fd, active_cache, active_nr) ||
 342              commit_locked_index(&index_lock)))
 343                 die("%s: Unable to write new index file", me);
 344         rollback_lock_file(&index_lock);
 345
 346         if (!clean) {
 347                 int i;
 348                 strbuf_addstr(msgbuf, "\nConflicts:\n\n");
 349                 for (i = 0; i < active_nr;) {
 350                         struct cache_entry *ce = active_cache[i++];
 351                         if (ce_stage(ce)) {
 352                                 strbuf_addch(msgbuf, '\t');
 353                                 strbuf_addstr(msgbuf, ce->name);
 354                                 strbuf_addch(msgbuf, '\n');
 355                                 while (i < active_nr && !strcmp(ce->name,
 356                                                 active_cache[i]->name))
 357                                         i++;
 358                         }
 359                 }
 360                 write_message(msgbuf, defmsg);
 361                 fprintf(stderr, "Automatic %s failed.%s\n",
 362                         me, help_msg());
 363                 rerere(allow_rerere_auto);
 364                 exit(1);
 365         }
 366         write_message(msgbuf, defmsg);
 367         fprintf(stderr, "Finished one %s.\n", me);
 368 }
 369
 370 static int do_pick_commit(void)
 371 {
 372         unsigned char head[20];
 373         struct commit *base, *next, *parent;
 374         const char *base_label, *next_label;
 375         struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
 376         char *defmsg = NULL;
 377         struct strbuf msgbuf = STRBUF_INIT;
 378
 379         if (no_commit) {
 380                 /*
 381                  * We do not intend to commit immediately.  We just want to
 382                  * merge the differences in, so let's compute the tree
 383                  * that represents the "current" state for merge-recursive
 384                  * to work on.
 385                  */
 386                 if (write_cache_as_tree(head, 0, NULL))
 387                         die ("Your index file is unmerged.");
 388         } else {
 389                 if (get_sha1("HEAD", head))
 390                         die ("You do not have a valid HEAD");
 391                 if (index_differs_from("HEAD", 0))
 392                         die_dirty_index(me);
 393         }
 394         discard_cache();
 395
 396         if (!commit->parents) {
 397                 if (action == REVERT)
 398                         die ("Cannot revert a root commit");
 399                 parent = NULL;
 400         }
 401         else if (commit->parents->next) {
 402                 /* Reverting or cherry-picking a merge commit */
 403                 int cnt;
 404                 struct commit_list *p;
 405
 406                 if (!mainline)
 407                         die("Commit %s is a merge but no -m option was given.",
 408                             sha1_to_hex(commit->object.sha1));
 409
 410                 for (cnt = 1, p = commit->parents;
 411                      cnt != mainline && p;
 412                      cnt++)
 413                         p = p->next;
 414                 if (cnt != mainline || !p)
 415                         die("Commit %s does not have parent %d",
 416                             sha1_to_hex(commit->object.sha1), mainline);
 417                 parent = p->item;
 418         } else if (0 < mainline)
 419                 die("Mainline was specified but commit %s is not a merge.",
 420                     sha1_to_hex(commit->object.sha1));
 421         else
 422                 parent = commit->parents->item;
 423
 424         if (allow_ff && !hashcmp(parent->object.sha1, head))
 425                 return fast_forward_to(commit->object.sha1, head);
 426
 427         if (parent && parse_commit(parent) < 0)
 428                 die("%s: cannot parse parent commit %s",
 429                     me, sha1_to_hex(parent->object.sha1));
 430
 431         if (get_message(commit->buffer, &msg) != 0)
 432                 die("Cannot get commit message for %s",
 433                                 sha1_to_hex(commit->object.sha1));
 434
 435         /*
 436          * "commit" is an existing commit.  We would want to apply
 437          * the difference it introduces since its first parent "prev"
 438          * on top of the current HEAD if we are cherry-pick.  Or the
 439          * reverse of it if we are revert.
 440          */
 441
 442         defmsg = git_pathdup("MERGE_MSG");
 443
 444         if (action == REVERT) {
 445                 base = commit;
 446                 base_label = msg.label;
 447                 next = parent;
 448                 next_label = msg.parent_label;
 449                 strbuf_addstr(&msgbuf, "Revert \"");
 450                 strbuf_addstr(&msgbuf, msg.subject);
 451                 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
 452                 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 453
 454                 if (commit->parents->next) {
 455                         strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
 456                         strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
 457                 }
 458                 strbuf_addstr(&msgbuf, ".\n");
 459         } else {
 460                 base = parent;
 461                 base_label = msg.parent_label;
 462                 next = commit;
 463                 next_label = msg.label;
 464                 set_author_ident_env(msg.message);
 465                 add_message_to_msg(&msgbuf, msg.message);
 466                 if (no_replay) {
 467                         strbuf_addstr(&msgbuf, "(cherry picked from commit ");
 468                         strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 469                         strbuf_addstr(&msgbuf, ")\n");
 470                 }
 471         }
 472
 473         if (!strategy || !strcmp(strategy, "recursive") || action == REVERT)
 474                 do_recursive_merge(base, next, base_label, next_label,
 475                                    head, &msgbuf, defmsg);
 476         else {
 477                 int res;
 478                 struct commit_list *common = NULL;
 479                 struct commit_list *remotes = NULL;
 480                 write_message(&msgbuf, defmsg);
 481                 commit_list_insert(base, &common);
 482                 commit_list_insert(next, &remotes);
 483                 res = try_merge_command(strategy, common,
 484                                         sha1_to_hex(head), remotes);
 485                 free_commit_list(common);
 486                 free_commit_list(remotes);
 487                 if (res) {
 488                         fprintf(stderr, "Automatic %s with strategy %s failed.%s\n",
 489                                 me, strategy, help_msg());
 490                         rerere(allow_rerere_auto);
 491                         exit(1);
 492                 }
 493         }
 494
 495         free_message(&msg);
 496
 497         /*
 498          * If we are cherry-pick, and if the merge did not result in
 499          * hand-editing, we will hit this commit and inherit the original
 500          * author date and name.
 501          * If we are revert, or if our cherry-pick results in a hand merge,
 502          * we had better say that the current user is responsible for that.
 503          */
 504
 505         if (!no_commit) {
 506                 /* 6 is max possible length of our args array including NULL */
 507                 const char *args[6];
 508                 int res;
 509                 int i = 0;
 510
 511                 args[i++] = "commit";
 512                 args[i++] = "-n";
 513                 if (signoff)
 514                         args[i++] = "-s";
 515                 if (!edit) {
 516                         args[i++] = "-F";
 517                         args[i++] = defmsg;
 518                 }
 519                 args[i] = NULL;
 520                 res = run_command_v_opt(args, RUN_GIT_CMD);
 521                 free(defmsg);
 522
 523                 return res;
 524         }
 525
 526         free(defmsg);
 527
 528         return 0;
 529 }
 530
 531 static void prepare_revs(struct rev_info *revs)
 532 {
 533         int argc;
 534
 535         init_revisions(revs, NULL);
 536         revs->no_walk = 1;
 537         if (action != REVERT)
 538                 revs->reverse = 1;
 539
 540         argc = setup_revisions(commit_argc, commit_argv, revs, NULL);
 541         if (argc > 1)
 542                 usage(*revert_or_cherry_pick_usage());
 543
 544         if (prepare_revision_walk(revs))
 545                 die("revision walk setup failed");
 546
 547         if (!revs->commits)
 548                 die("empty commit set passed");
 549 }
 550
 551 static int revert_or_cherry_pick(int argc, const char **argv)
 552 {
 553         struct rev_info revs;
 554
 555         git_config(git_default_config, NULL);
 556         me = action == REVERT ? "revert" : "cherry-pick";
 557         setenv(GIT_REFLOG_ACTION, me, 0);
 558         parse_args(argc, argv);
 559
 560         if (allow_ff) {
 561                 if (signoff)
 562                         die("cherry-pick --ff cannot be used with --signoff");
 563                 if (no_commit)
 564                         die("cherry-pick --ff cannot be used with --no-commit");
 565                 if (no_replay)
 566                         die("cherry-pick --ff cannot be used with -x");
 567                 if (edit)
 568                         die("cherry-pick --ff cannot be used with --edit");
 569         }
 570
 571         if (read_cache() < 0)
 572                 die("git %s: failed to read the index", me);
 573
 574         prepare_revs(&revs);
 575
 576         while ((commit = get_revision(&revs))) {
 577                 int res = do_pick_commit();
 578                 if (res)
 579                         return res;
 580         }
 581
 582         return 0;
 583 }
 584
 585 int cmd_revert(int argc, const char **argv, const char *prefix)
 586 {
 587         if (isatty(0))
 588                 edit = 1;
 589         action = REVERT;
 590         return revert_or_cherry_pick(argc, argv);
 591 }
 592
 593 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
 594 {
 595         action = CHERRY_PICK;
 596         return revert_or_cherry_pick(argc, argv);
 597 }