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 void parse_args(int argc, const char **argv)
  54 {
  55         const char * const * usage_str =
  56                 action == REVERT ?  revert_usage : cherry_pick_usage;
  57         int noop;
  58         struct option options[] = {
  59                 OPT_BOOLEAN('n', "no-commit", &no_commit, "don't automatically commit"),
  60                 OPT_BOOLEAN('e', "edit", &edit, "edit the commit message"),
  61                 OPT_BOOLEAN('r', NULL, &noop, "no-op (backward compatibility)"),
  62                 OPT_BOOLEAN('s', "signoff", &signoff, "add Signed-off-by:"),
  63                 OPT_INTEGER('m', "mainline", &mainline, "parent number"),
  64                 OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
  65                 OPT_STRING(0, "strategy", &strategy, "strategy", "merge strategy"),
  66                 OPT_END(),
  67                 OPT_END(),
  68                 OPT_END(),
  69         };
  70
  71         if (action == CHERRY_PICK) {
  72                 struct option cp_extra[] = {
  73                         OPT_BOOLEAN('x', NULL, &no_replay, "append commit name"),
  74                         OPT_BOOLEAN(0, "ff", &allow_ff, "allow fast-forward"),
  75                         OPT_END(),
  76                 };
  77                 if (parse_options_concat(options, ARRAY_SIZE(options), cp_extra))
  78                         die("program error");
  79         }
  80
  81         commit_argc = parse_options(argc, argv, NULL, options, usage_str,
  82                                     PARSE_OPT_KEEP_UNKNOWN);
  83         if (commit_argc < 1)
  84                 usage_with_options(usage_str, options);
  85
  86         commit_argv = argv;
  87 }
  88
  89 struct commit_message {
  90         char *parent_label;
  91         const char *label;
  92         const char *subject;
  93         char *reencoded_message;
  94         const char *message;
  95 };
  96
  97 static int get_message(const char *raw_message, struct commit_message *out)
  98 {
  99         const char *encoding;
 100         const char *p, *abbrev, *eol;
 101         char *q;
 102         int abbrev_len, oneline_len;
 103
 104         if (!raw_message)
 105                 return -1;
 106         encoding = get_encoding(raw_message);
 107         if (!encoding)
 108                 encoding = "UTF-8";
 109         if (!git_commit_encoding)
 110                 git_commit_encoding = "UTF-8";
 111
 112         out->reencoded_message = NULL;
 113         out->message = raw_message;
 114         if (strcmp(encoding, git_commit_encoding))
 115                 out->reencoded_message = reencode_string(raw_message,
 116                                         git_commit_encoding, encoding);
 117         if (out->reencoded_message)
 118                 out->message = out->reencoded_message;
 119
 120         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
 121         abbrev_len = strlen(abbrev);
 122
 123         /* Find beginning and end of commit subject. */
 124         p = out->message;
 125         while (*p && (*p != '\n' || p[1] != '\n'))
 126                 p++;
 127         if (*p) {
 128                 p += 2;
 129                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
 130                         ; /* do nothing */
 131         } else
 132                 eol = p;
 133         oneline_len = eol - p;
 134
 135         out->parent_label = xmalloc(strlen("parent of ") + abbrev_len +
 136                               strlen("... ") + oneline_len + 1);
 137         q = out->parent_label;
 138         q = mempcpy(q, "parent of ", strlen("parent of "));
 139         out->label = q;
 140         q = mempcpy(q, abbrev, abbrev_len);
 141         q = mempcpy(q, "... ", strlen("... "));
 142         out->subject = q;
 143         q = mempcpy(q, p, oneline_len);
 144         *q = '\0';
 145         return 0;
 146 }
 147
 148 static void free_message(struct commit_message *msg)
 149 {
 150         free(msg->parent_label);
 151         free(msg->reencoded_message);
 152 }
 153
 154 static char *get_encoding(const char *message)
 155 {
 156         const char *p = message, *eol;
 157
 158         if (!p)
 159                 die ("Could not read commit message of %s",
 160                                 sha1_to_hex(commit->object.sha1));
 161         while (*p && *p != '\n') {
 162                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
 163                         ; /* do nothing */
 164                 if (!prefixcmp(p, "encoding ")) {
 165                         char *result = xmalloc(eol - 8 - p);
 166                         strlcpy(result, p + 9, eol - 8 - p);
 167                         return result;
 168                 }
 169                 p = eol;
 170                 if (*p == '\n')
 171                         p++;
 172         }
 173         return NULL;
 174 }
 175
 176 static void add_message_to_msg(struct strbuf *msgbuf, const char *message)
 177 {
 178         const char *p = message;
 179         while (*p && (*p != '\n' || p[1] != '\n'))
 180                 p++;
 181
 182         if (!*p)
 183                 strbuf_addstr(msgbuf, sha1_to_hex(commit->object.sha1));
 184
 185         p += 2;
 186         strbuf_addstr(msgbuf, p);
 187 }
 188
 189 static void set_author_ident_env(const char *message)
 190 {
 191         const char *p = message;
 192         if (!p)
 193                 die ("Could not read commit message of %s",
 194                                 sha1_to_hex(commit->object.sha1));
 195         while (*p && *p != '\n') {
 196                 const char *eol;
 197
 198                 for (eol = p; *eol && *eol != '\n'; eol++)
 199                         ; /* do nothing */
 200                 if (!prefixcmp(p, "author ")) {
 201                         char *line, *pend, *email, *timestamp;
 202
 203                         p += 7;
 204                         line = xmemdupz(p, eol - p);
 205                         email = strchr(line, '<');
 206                         if (!email)
 207                                 die ("Could not extract author email from %s",
 208                                         sha1_to_hex(commit->object.sha1));
 209                         if (email == line)
 210                                 pend = line;
 211                         else
 212                                 for (pend = email; pend != line + 1 &&
 213                                                 isspace(pend[-1]); pend--);
 214                                         ; /* do nothing */
 215                         *pend = '\0';
 216                         email++;
 217                         timestamp = strchr(email, '>');
 218                         if (!timestamp)
 219                                 die ("Could not extract author time from %s",
 220                                         sha1_to_hex(commit->object.sha1));
 221                         *timestamp = '\0';
 222                         for (timestamp++; *timestamp && isspace(*timestamp);
 223                                         timestamp++)
 224                                 ; /* do nothing */
 225                         setenv("GIT_AUTHOR_NAME", line, 1);
 226                         setenv("GIT_AUTHOR_EMAIL", email, 1);
 227                         setenv("GIT_AUTHOR_DATE", timestamp, 1);
 228                         free(line);
 229                         return;
 230                 }
 231                 p = eol;
 232                 if (*p == '\n')
 233                         p++;
 234         }
 235         die ("No author information found in %s",
 236                         sha1_to_hex(commit->object.sha1));
 237 }
 238
 239 static char *help_msg(void)
 240 {
 241         struct strbuf helpbuf = STRBUF_INIT;
 242         char *msg = getenv("GIT_CHERRY_PICK_HELP");
 243
 244         if (msg)
 245                 return msg;
 246
 247         strbuf_addstr(&helpbuf, "  After resolving the conflicts,\n"
 248                 "mark the corrected paths with 'git add <paths>' or 'git rm <paths>'\n"
 249                 "and commit the result");
 250
 251         if (action == CHERRY_PICK) {
 252                 strbuf_addf(&helpbuf, " with: \n"
 253                         "\n"
 254                         "        git commit -c %s\n",
 255                             sha1_to_hex(commit->object.sha1));
 256         }
 257         else
 258                 strbuf_addch(&helpbuf, '.');
 259         return strbuf_detach(&helpbuf, NULL);
 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(const char *me)
 286 {
 287         if (read_cache_unmerged()) {
 288                 die_resolve_conflict(me);
 289         } else {
 290                 if (advice_commit_before_merge)
 291                         die("Your local changes would be overwritten by %s.\n"
 292                             "Please, commit your changes or stash them to proceed.", me);
 293                 else
 294                         die("Your local changes would be overwritten by %s.\n", me);
 295         }
 296 }
 297
 298 static int fast_forward_to(const unsigned char *to, const unsigned char *from)
 299 {
 300         struct ref_lock *ref_lock;
 301
 302         read_cache();
 303         if (checkout_fast_forward(from, to))
 304                 exit(1); /* the callee should have complained already */
 305         ref_lock = lock_any_ref_for_update("HEAD", from, 0);
 306         return write_ref_sha1(ref_lock, to, "cherry-pick");
 307 }
 308
 309 static void do_recursive_merge(struct commit *base, struct commit *next,
 310                                const char *base_label, const char *next_label,
 311                                unsigned char *head, struct strbuf *msgbuf,
 312                                char *defmsg)
 313 {
 314         struct merge_options o;
 315         struct tree *result, *next_tree, *base_tree, *head_tree;
 316         int clean, index_fd;
 317         static struct lock_file index_lock;
 318
 319         index_fd = hold_locked_index(&index_lock, 1);
 320
 321         read_cache();
 322         init_merge_options(&o);
 323         o.ancestor = base ? base_label : "(empty tree)";
 324         o.branch1 = "HEAD";
 325         o.branch2 = next ? next_label : "(empty tree)";
 326
 327         head_tree = parse_tree_indirect(head);
 328         next_tree = next ? next->tree : empty_tree();
 329         base_tree = base ? base->tree : empty_tree();
 330
 331         clean = merge_trees(&o,
 332                             head_tree,
 333                             next_tree, base_tree, &result);
 334
 335         if (active_cache_changed &&
 336             (write_cache(index_fd, active_cache, active_nr) ||
 337              commit_locked_index(&index_lock)))
 338                 die("%s: Unable to write new index file", me);
 339         rollback_lock_file(&index_lock);
 340
 341         if (!clean) {
 342                 int i;
 343                 strbuf_addstr(msgbuf, "\nConflicts:\n\n");
 344                 for (i = 0; i < active_nr;) {
 345                         struct cache_entry *ce = active_cache[i++];
 346                         if (ce_stage(ce)) {
 347                                 strbuf_addch(msgbuf, '\t');
 348                                 strbuf_addstr(msgbuf, ce->name);
 349                                 strbuf_addch(msgbuf, '\n');
 350                                 while (i < active_nr && !strcmp(ce->name,
 351                                                 active_cache[i]->name))
 352                                         i++;
 353                         }
 354                 }
 355                 write_message(msgbuf, defmsg);
 356                 fprintf(stderr, "Automatic %s failed.%s\n",
 357                         me, help_msg());
 358                 rerere(allow_rerere_auto);
 359                 exit(1);
 360         }
 361         write_message(msgbuf, defmsg);
 362         fprintf(stderr, "Finished one %s.\n", me);
 363 }
 364
 365 static int do_pick_commit(void)
 366 {
 367         unsigned char head[20];
 368         struct commit *base, *next, *parent;
 369         const char *base_label, *next_label;
 370         struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
 371         char *defmsg = NULL;
 372         struct strbuf msgbuf = STRBUF_INIT;
 373
 374         if (no_commit) {
 375                 /*
 376                  * We do not intend to commit immediately.  We just want to
 377                  * merge the differences in, so let's compute the tree
 378                  * that represents the "current" state for merge-recursive
 379                  * to work on.
 380                  */
 381                 if (write_cache_as_tree(head, 0, NULL))
 382                         die ("Your index file is unmerged.");
 383         } else {
 384                 if (get_sha1("HEAD", head))
 385                         die ("You do not have a valid HEAD");
 386                 if (index_differs_from("HEAD", 0))
 387                         die_dirty_index(me);
 388         }
 389         discard_cache();
 390
 391         if (!commit->parents) {
 392                 if (action == REVERT)
 393                         die ("Cannot revert a root commit");
 394                 parent = NULL;
 395         }
 396         else if (commit->parents->next) {
 397                 /* Reverting or cherry-picking a merge commit */
 398                 int cnt;
 399                 struct commit_list *p;
 400
 401                 if (!mainline)
 402                         die("Commit %s is a merge but no -m option was given.",
 403                             sha1_to_hex(commit->object.sha1));
 404
 405                 for (cnt = 1, p = commit->parents;
 406                      cnt != mainline && p;
 407                      cnt++)
 408                         p = p->next;
 409                 if (cnt != mainline || !p)
 410                         die("Commit %s does not have parent %d",
 411                             sha1_to_hex(commit->object.sha1), mainline);
 412                 parent = p->item;
 413         } else if (0 < mainline)
 414                 die("Mainline was specified but commit %s is not a merge.",
 415                     sha1_to_hex(commit->object.sha1));
 416         else
 417                 parent = commit->parents->item;
 418
 419         if (allow_ff && !hashcmp(parent->object.sha1, head))
 420                 return fast_forward_to(commit->object.sha1, head);
 421
 422         if (parent && parse_commit(parent) < 0)
 423                 die("%s: cannot parse parent commit %s",
 424                     me, sha1_to_hex(parent->object.sha1));
 425
 426         if (get_message(commit->buffer, &msg) != 0)
 427                 die("Cannot get commit message for %s",
 428                                 sha1_to_hex(commit->object.sha1));
 429
 430         /*
 431          * "commit" is an existing commit.  We would want to apply
 432          * the difference it introduces since its first parent "prev"
 433          * on top of the current HEAD if we are cherry-pick.  Or the
 434          * reverse of it if we are revert.
 435          */
 436
 437         defmsg = git_pathdup("MERGE_MSG");
 438
 439         if (action == REVERT) {
 440                 base = commit;
 441                 base_label = msg.label;
 442                 next = parent;
 443                 next_label = msg.parent_label;
 444                 strbuf_addstr(&msgbuf, "Revert \"");
 445                 strbuf_addstr(&msgbuf, msg.subject);
 446                 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
 447                 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 448
 449                 if (commit->parents->next) {
 450                         strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
 451                         strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
 452                 }
 453                 strbuf_addstr(&msgbuf, ".\n");
 454         } else {
 455                 base = parent;
 456                 base_label = msg.parent_label;
 457                 next = commit;
 458                 next_label = msg.label;
 459                 set_author_ident_env(msg.message);
 460                 add_message_to_msg(&msgbuf, msg.message);
 461                 if (no_replay) {
 462                         strbuf_addstr(&msgbuf, "(cherry picked from commit ");
 463                         strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 464                         strbuf_addstr(&msgbuf, ")\n");
 465                 }
 466         }
 467
 468         if (!strategy || !strcmp(strategy, "recursive") || action == REVERT)
 469                 do_recursive_merge(base, next, base_label, next_label,
 470                                    head, &msgbuf, defmsg);
 471         else {
 472                 int res;
 473                 struct commit_list *common = NULL;
 474                 struct commit_list *remotes = NULL;
 475                 write_message(&msgbuf, defmsg);
 476                 commit_list_insert(base, &common);
 477                 commit_list_insert(next, &remotes);
 478                 res = try_merge_command(strategy, common,
 479                                         sha1_to_hex(head), remotes);
 480                 free_commit_list(common);
 481                 free_commit_list(remotes);
 482                 if (res) {
 483                         fprintf(stderr, "Automatic %s with strategy %s failed.%s\n",
 484                                 me, strategy, help_msg());
 485                         rerere(allow_rerere_auto);
 486                         exit(1);
 487                 }
 488         }
 489
 490         free_message(&msg);
 491
 492         /*
 493          *
 494          * If we are cherry-pick, and if the merge did not result in
 495          * hand-editing, we will hit this commit and inherit the original
 496          * author date and name.
 497          * If we are revert, or if our cherry-pick results in a hand merge,
 498          * we had better say that the current user is responsible for that.
 499          */
 500
 501         if (!no_commit) {
 502                 /* 6 is max possible length of our args array including NULL */
 503                 const char *args[6];
 504                 int res;
 505                 int i = 0;
 506
 507                 args[i++] = "commit";
 508                 args[i++] = "-n";
 509                 if (signoff)
 510                         args[i++] = "-s";
 511                 if (!edit) {
 512                         args[i++] = "-F";
 513                         args[i++] = defmsg;
 514                 }
 515                 args[i] = NULL;
 516                 res = run_command_v_opt(args, RUN_GIT_CMD);
 517                 free(defmsg);
 518
 519                 return res;
 520         }
 521
 522         free(defmsg);
 523
 524         return 0;
 525 }
 526
 527 static void prepare_revs(struct rev_info *revs)
 528 {
 529         int argc = 0;
 530         int i;
 531         const char **argv = xmalloc((commit_argc + 4) * sizeof(*argv));
 532
 533         argv[argc++] = NULL;
 534         argv[argc++] = "--no-walk";
 535         if (action != REVERT)
 536                 argv[argc++] = "--reverse";
 537         for (i = 0; i < commit_argc; i++)
 538                 argv[argc++] = commit_argv[i];
 539         argv[argc++] = NULL;
 540
 541         init_revisions(revs, NULL);
 542         setup_revisions(argc - 1, argv, revs, NULL);
 543         if (prepare_revision_walk(revs))
 544                 die("revision walk setup failed");
 545
 546         if (!revs->commits)
 547                 die("empty commit set passed");
 548
 549         free(argv);
 550 }
 551
 552 static int revert_or_cherry_pick(int argc, const char **argv)
 553 {
 554         struct rev_info revs;
 555
 556         git_config(git_default_config, NULL);
 557         me = action == REVERT ? "revert" : "cherry-pick";
 558         setenv(GIT_REFLOG_ACTION, me, 0);
 559         parse_args(argc, argv);
 560
 561         if (allow_ff) {
 562                 if (signoff)
 563                         die("cherry-pick --ff cannot be used with --signoff");
 564                 if (no_commit)
 565                         die("cherry-pick --ff cannot be used with --no-commit");
 566                 if (no_replay)
 567                         die("cherry-pick --ff cannot be used with -x");
 568                 if (edit)
 569                         die("cherry-pick --ff cannot be used with --edit");
 570         }
 571
 572         if (read_cache() < 0)
 573                 die("git %s: failed to read the index", 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 }