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 int 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 {
 318         struct merge_options o;
 319         struct tree *result, *next_tree, *base_tree, *head_tree;
 320         int clean, index_fd;
 321         static struct lock_file index_lock;
 322
 323         index_fd = hold_locked_index(&index_lock, 1);
 324
 325         read_cache();
 326         init_merge_options(&o);
 327         o.ancestor = base ? base_label : "(empty tree)";
 328         o.branch1 = "HEAD";
 329         o.branch2 = next ? next_label : "(empty tree)";
 330
 331         head_tree = parse_tree_indirect(head);
 332         next_tree = next ? next->tree : empty_tree();
 333         base_tree = base ? base->tree : empty_tree();
 334
 335         clean = merge_trees(&o,
 336                             head_tree,
 337                             next_tree, base_tree, &result);
 338
 339         if (active_cache_changed &&
 340             (write_cache(index_fd, active_cache, active_nr) ||
 341              commit_locked_index(&index_lock)))
 342                 die("%s: Unable to write new index file", me);
 343         rollback_lock_file(&index_lock);
 344
 345         if (!clean) {
 346                 int i;
 347                 strbuf_addstr(msgbuf, "\nConflicts:\n\n");
 348                 for (i = 0; i < active_nr;) {
 349                         struct cache_entry *ce = active_cache[i++];
 350                         if (ce_stage(ce)) {
 351                                 strbuf_addch(msgbuf, '\t');
 352                                 strbuf_addstr(msgbuf, ce->name);
 353                                 strbuf_addch(msgbuf, '\n');
 354                                 while (i < active_nr && !strcmp(ce->name,
 355                                                 active_cache[i]->name))
 356                                         i++;
 357                         }
 358                 }
 359         }
 360
 361         return !clean;
 362 }
 363
 364 /*
 365  * If we are cherry-pick, and if the merge did not result in
 366  * hand-editing, we will hit this commit and inherit the original
 367  * author date and name.
 368  * If we are revert, or if our cherry-pick results in a hand merge,
 369  * we had better say that the current user is responsible for that.
 370  */
 371 static int run_git_commit(const char *defmsg)
 372 {
 373         /* 6 is max possible length of our args array including NULL */
 374         const char *args[6];
 375         int i = 0;
 376
 377         args[i++] = "commit";
 378         args[i++] = "-n";
 379         if (signoff)
 380                 args[i++] = "-s";
 381         if (!edit) {
 382                 args[i++] = "-F";
 383                 args[i++] = defmsg;
 384         }
 385         args[i] = NULL;
 386
 387         return run_command_v_opt(args, RUN_GIT_CMD);
 388 }
 389
 390 static int do_pick_commit(void)
 391 {
 392         unsigned char head[20];
 393         struct commit *base, *next, *parent;
 394         const char *base_label, *next_label;
 395         struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
 396         char *defmsg = NULL;
 397         struct strbuf msgbuf = STRBUF_INIT;
 398         struct strbuf mebuf = STRBUF_INIT;
 399         int res;
 400
 401         if (no_commit) {
 402                 /*
 403                  * We do not intend to commit immediately.  We just want to
 404                  * merge the differences in, so let's compute the tree
 405                  * that represents the "current" state for merge-recursive
 406                  * to work on.
 407                  */
 408                 if (write_cache_as_tree(head, 0, NULL))
 409                         die ("Your index file is unmerged.");
 410         } else {
 411                 if (get_sha1("HEAD", head))
 412                         die ("You do not have a valid HEAD");
 413                 if (index_differs_from("HEAD", 0))
 414                         die_dirty_index(me);
 415         }
 416         discard_cache();
 417
 418         if (!commit->parents) {
 419                 if (action == REVERT)
 420                         die ("Cannot revert a root commit");
 421                 parent = NULL;
 422         }
 423         else if (commit->parents->next) {
 424                 /* Reverting or cherry-picking a merge commit */
 425                 int cnt;
 426                 struct commit_list *p;
 427
 428                 if (!mainline)
 429                         die("Commit %s is a merge but no -m option was given.",
 430                             sha1_to_hex(commit->object.sha1));
 431
 432                 for (cnt = 1, p = commit->parents;
 433                      cnt != mainline && p;
 434                      cnt++)
 435                         p = p->next;
 436                 if (cnt != mainline || !p)
 437                         die("Commit %s does not have parent %d",
 438                             sha1_to_hex(commit->object.sha1), mainline);
 439                 parent = p->item;
 440         } else if (0 < mainline)
 441                 die("Mainline was specified but commit %s is not a merge.",
 442                     sha1_to_hex(commit->object.sha1));
 443         else
 444                 parent = commit->parents->item;
 445
 446         if (allow_ff && !hashcmp(parent->object.sha1, head))
 447                 return fast_forward_to(commit->object.sha1, head);
 448
 449         if (parent && parse_commit(parent) < 0)
 450                 die("%s: cannot parse parent commit %s",
 451                     me, sha1_to_hex(parent->object.sha1));
 452
 453         if (get_message(commit->buffer, &msg) != 0)
 454                 die("Cannot get commit message for %s",
 455                                 sha1_to_hex(commit->object.sha1));
 456
 457         /*
 458          * "commit" is an existing commit.  We would want to apply
 459          * the difference it introduces since its first parent "prev"
 460          * on top of the current HEAD if we are cherry-pick.  Or the
 461          * reverse of it if we are revert.
 462          */
 463
 464         defmsg = git_pathdup("MERGE_MSG");
 465
 466         if (action == REVERT) {
 467                 base = commit;
 468                 base_label = msg.label;
 469                 next = parent;
 470                 next_label = msg.parent_label;
 471                 strbuf_addstr(&msgbuf, "Revert \"");
 472                 strbuf_addstr(&msgbuf, msg.subject);
 473                 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
 474                 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 475
 476                 if (commit->parents->next) {
 477                         strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
 478                         strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
 479                 }
 480                 strbuf_addstr(&msgbuf, ".\n");
 481         } else {
 482                 base = parent;
 483                 base_label = msg.parent_label;
 484                 next = commit;
 485                 next_label = msg.label;
 486                 set_author_ident_env(msg.message);
 487                 add_message_to_msg(&msgbuf, msg.message);
 488                 if (no_replay) {
 489                         strbuf_addstr(&msgbuf, "(cherry picked from commit ");
 490                         strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 491                         strbuf_addstr(&msgbuf, ")\n");
 492                 }
 493         }
 494
 495         strbuf_addf(&mebuf, "%s of commit %s", me,
 496                     find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
 497
 498         if (!strategy || !strcmp(strategy, "recursive") || action == REVERT) {
 499                 res = do_recursive_merge(base, next, base_label, next_label,
 500                                          head, &msgbuf);
 501                 write_message(&msgbuf, defmsg);
 502         } else {
 503                 struct commit_list *common = NULL;
 504                 struct commit_list *remotes = NULL;
 505
 506                 strbuf_addf(&mebuf, " with strategy %s", strategy);
 507                 write_message(&msgbuf, defmsg);
 508
 509                 commit_list_insert(base, &common);
 510                 commit_list_insert(next, &remotes);
 511                 res = try_merge_command(strategy, common,
 512                                         sha1_to_hex(head), remotes);
 513                 free_commit_list(common);
 514                 free_commit_list(remotes);
 515         }
 516
 517         if (res) {
 518                 fprintf(stderr, "Automatic %s failed.%s\n",
 519                         mebuf.buf, help_msg());
 520                 rerere(allow_rerere_auto);
 521         } else {
 522                 if (!no_commit)
 523                         res = run_git_commit(defmsg);
 524                 if (!res)
 525                         fprintf(stderr, "Finished %s.\n", mebuf.buf);
 526         }
 527
 528         strbuf_release(&mebuf);
 529         free_message(&msg);
 530         free(defmsg);
 531
 532         return res;
 533 }
 534
 535 static void prepare_revs(struct rev_info *revs)
 536 {
 537         int argc;
 538
 539         init_revisions(revs, NULL);
 540         revs->no_walk = 1;
 541         if (action != REVERT)
 542                 revs->reverse = 1;
 543
 544         argc = setup_revisions(commit_argc, commit_argv, revs, NULL);
 545         if (argc > 1)
 546                 usage(*revert_or_cherry_pick_usage());
 547
 548         if (prepare_revision_walk(revs))
 549                 die("revision walk setup failed");
 550
 551         if (!revs->commits)
 552                 die("empty commit set passed");
 553 }
 554
 555 static int revert_or_cherry_pick(int argc, const char **argv)
 556 {
 557         struct rev_info revs;
 558
 559         git_config(git_default_config, NULL);
 560         me = action == REVERT ? "revert" : "cherry-pick";
 561         setenv(GIT_REFLOG_ACTION, me, 0);
 562         parse_args(argc, argv);
 563
 564         if (allow_ff) {
 565                 if (signoff)
 566                         die("cherry-pick --ff cannot be used with --signoff");
 567                 if (no_commit)
 568                         die("cherry-pick --ff cannot be used with --no-commit");
 569                 if (no_replay)
 570                         die("cherry-pick --ff cannot be used with -x");
 571                 if (edit)
 572                         die("cherry-pick --ff cannot be used with --edit");
 573         }
 574
 575         if (read_cache() < 0)
 576                 die("git %s: failed to read the index", me);
 577
 578         prepare_revs(&revs);
 579
 580         while ((commit = get_revision(&revs))) {
 581                 int res = do_pick_commit();
 582                 if (res)
 583                         return res;
 584         }
 585
 586         return 0;
 587 }
 588
 589 int cmd_revert(int argc, const char **argv, const char *prefix)
 590 {
 591         if (isatty(0))
 592                 edit = 1;
 593         action = REVERT;
 594         return revert_or_cherry_pick(argc, argv);
 595 }
 596
 597 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
 598 {
 599         action = CHERRY_PICK;
 600         return revert_or_cherry_pick(argc, argv);
 601 }