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 const char *commit_name;
  43 static int allow_rerere_auto;
  44
  45 static const char *me;
  46 static const char *strategy;
  47
  48 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
  49
  50 static char *get_encoding(const char *message);
  51
  52 static void parse_args(int argc, const char **argv)
  53 {
  54         const char * const * usage_str =
  55                 action == REVERT ?  revert_usage : cherry_pick_usage;
  56         int noop;
  57         struct option options[] = {
  58                 OPT_BOOLEAN('n', "no-commit", &no_commit, "don't automatically commit"),
  59                 OPT_BOOLEAN('e', "edit", &edit, "edit the commit message"),
  60                 OPT_BOOLEAN('x', NULL, &no_replay, "append commit name when cherry-picking"),
  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(0, "ff", &allow_ff, "allow fast-forward"),
  74                         OPT_END(),
  75                 };
  76                 if (parse_options_concat(options, ARRAY_SIZE(options), cp_extra))
  77                         die("program error");
  78         }
  79
  80         if (parse_options(argc, argv, NULL, options, usage_str, 0) != 1)
  81                 usage_with_options(usage_str, options);
  82
  83         commit_name = argv[0];
  84 }
  85
  86 struct commit_message {
  87         char *parent_label;
  88         const char *label;
  89         const char *subject;
  90         char *reencoded_message;
  91         const char *message;
  92 };
  93
  94 static int get_message(const char *raw_message, struct commit_message *out)
  95 {
  96         const char *encoding;
  97         const char *p, *abbrev, *eol;
  98         char *q;
  99         int abbrev_len, oneline_len;
 100
 101         if (!raw_message)
 102                 return -1;
 103         encoding = get_encoding(raw_message);
 104         if (!encoding)
 105                 encoding = "UTF-8";
 106         if (!git_commit_encoding)
 107                 git_commit_encoding = "UTF-8";
 108
 109         out->reencoded_message = NULL;
 110         out->message = raw_message;
 111         if (strcmp(encoding, git_commit_encoding))
 112                 out->reencoded_message = reencode_string(raw_message,
 113                                         git_commit_encoding, encoding);
 114         if (out->reencoded_message)
 115                 out->message = out->reencoded_message;
 116
 117         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
 118         abbrev_len = strlen(abbrev);
 119
 120         /* Find beginning and end of commit subject. */
 121         p = out->message;
 122         while (*p && (*p != '\n' || p[1] != '\n'))
 123                 p++;
 124         if (*p) {
 125                 p += 2;
 126                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
 127                         ; /* do nothing */
 128         } else
 129                 eol = p;
 130         oneline_len = eol - p;
 131
 132         out->parent_label = xmalloc(strlen("parent of ") + abbrev_len +
 133                               strlen("... ") + oneline_len + 1);
 134         q = out->parent_label;
 135         q = mempcpy(q, "parent of ", strlen("parent of "));
 136         out->label = q;
 137         q = mempcpy(q, abbrev, abbrev_len);
 138         q = mempcpy(q, "... ", strlen("... "));
 139         out->subject = q;
 140         q = mempcpy(q, p, oneline_len);
 141         *q = '\0';
 142         return 0;
 143 }
 144
 145 static void free_message(struct commit_message *msg)
 146 {
 147         free(msg->parent_label);
 148         free(msg->reencoded_message);
 149 }
 150
 151 static char *get_encoding(const char *message)
 152 {
 153         const char *p = message, *eol;
 154
 155         if (!p)
 156                 die ("Could not read commit message of %s",
 157                                 sha1_to_hex(commit->object.sha1));
 158         while (*p && *p != '\n') {
 159                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
 160                         ; /* do nothing */
 161                 if (!prefixcmp(p, "encoding ")) {
 162                         char *result = xmalloc(eol - 8 - p);
 163                         strlcpy(result, p + 9, eol - 8 - p);
 164                         return result;
 165                 }
 166                 p = eol;
 167                 if (*p == '\n')
 168                         p++;
 169         }
 170         return NULL;
 171 }
 172
 173 static void add_message_to_msg(struct strbuf *msgbuf, const char *message)
 174 {
 175         const char *p = message;
 176         while (*p && (*p != '\n' || p[1] != '\n'))
 177                 p++;
 178
 179         if (!*p)
 180                 strbuf_addstr(msgbuf, sha1_to_hex(commit->object.sha1));
 181
 182         p += 2;
 183         strbuf_addstr(msgbuf, p);
 184 }
 185
 186 static void set_author_ident_env(const char *message)
 187 {
 188         const char *p = message;
 189         if (!p)
 190                 die ("Could not read commit message of %s",
 191                                 sha1_to_hex(commit->object.sha1));
 192         while (*p && *p != '\n') {
 193                 const char *eol;
 194
 195                 for (eol = p; *eol && *eol != '\n'; eol++)
 196                         ; /* do nothing */
 197                 if (!prefixcmp(p, "author ")) {
 198                         char *line, *pend, *email, *timestamp;
 199
 200                         p += 7;
 201                         line = xmemdupz(p, eol - p);
 202                         email = strchr(line, '<');
 203                         if (!email)
 204                                 die ("Could not extract author email from %s",
 205                                         sha1_to_hex(commit->object.sha1));
 206                         if (email == line)
 207                                 pend = line;
 208                         else
 209                                 for (pend = email; pend != line + 1 &&
 210                                                 isspace(pend[-1]); pend--);
 211                                         ; /* do nothing */
 212                         *pend = '\0';
 213                         email++;
 214                         timestamp = strchr(email, '>');
 215                         if (!timestamp)
 216                                 die ("Could not extract author time from %s",
 217                                         sha1_to_hex(commit->object.sha1));
 218                         *timestamp = '\0';
 219                         for (timestamp++; *timestamp && isspace(*timestamp);
 220                                         timestamp++)
 221                                 ; /* do nothing */
 222                         setenv("GIT_AUTHOR_NAME", line, 1);
 223                         setenv("GIT_AUTHOR_EMAIL", email, 1);
 224                         setenv("GIT_AUTHOR_DATE", timestamp, 1);
 225                         free(line);
 226                         return;
 227                 }
 228                 p = eol;
 229                 if (*p == '\n')
 230                         p++;
 231         }
 232         die ("No author information found in %s",
 233                         sha1_to_hex(commit->object.sha1));
 234 }
 235
 236 static char *help_msg(const char *name)
 237 {
 238         struct strbuf helpbuf = STRBUF_INIT;
 239         char *msg = getenv("GIT_CHERRY_PICK_HELP");
 240
 241         if (msg)
 242                 return msg;
 243
 244         strbuf_addstr(&helpbuf, "  After resolving the conflicts,\n"
 245                 "mark the corrected paths with 'git add <paths>' or 'git rm <paths>'\n"
 246                 "and commit the result");
 247
 248         if (action == CHERRY_PICK) {
 249                 strbuf_addf(&helpbuf, " with: \n"
 250                         "\n"
 251                         "        git commit -c %s\n",
 252                         name);
 253         }
 254         else
 255                 strbuf_addch(&helpbuf, '.');
 256         return strbuf_detach(&helpbuf, NULL);
 257 }
 258
 259 static void write_message(struct strbuf *msgbuf, const char *filename)
 260 {
 261         static struct lock_file msg_file;
 262
 263         int msg_fd = hold_lock_file_for_update(&msg_file, filename,
 264                                                LOCK_DIE_ON_ERROR);
 265         if (write_in_full(msg_fd, msgbuf->buf, msgbuf->len) < 0)
 266                 die_errno("Could not write to %s.", filename);
 267         strbuf_release(msgbuf);
 268         if (commit_lock_file(&msg_file) < 0)
 269                 die("Error wrapping up %s", filename);
 270 }
 271
 272 static struct tree *empty_tree(void)
 273 {
 274         struct tree *tree = xcalloc(1, sizeof(struct tree));
 275
 276         tree->object.parsed = 1;
 277         tree->object.type = OBJ_TREE;
 278         pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
 279         return tree;
 280 }
 281
 282 static NORETURN void die_dirty_index(const char *me)
 283 {
 284         if (read_cache_unmerged()) {
 285                 die_resolve_conflict(me);
 286         } else {
 287                 if (advice_commit_before_merge)
 288                         die("Your local changes would be overwritten by %s.\n"
 289                             "Please, commit your changes or stash them to proceed.", me);
 290                 else
 291                         die("Your local changes would be overwritten by %s.\n", me);
 292         }
 293 }
 294
 295 static int fast_forward_to(const unsigned char *to, const unsigned char *from)
 296 {
 297         struct ref_lock *ref_lock;
 298
 299         read_cache();
 300         if (checkout_fast_forward(from, to))
 301                 exit(1); /* the callee should have complained already */
 302         ref_lock = lock_any_ref_for_update("HEAD", from, 0);
 303         return write_ref_sha1(ref_lock, to, "cherry-pick");
 304 }
 305
 306 static void do_recursive_merge(struct commit *base, struct commit *next,
 307                                const char *base_label, const char *next_label,
 308                                unsigned char *head, struct strbuf *msgbuf,
 309                                char *defmsg)
 310 {
 311         struct merge_options o;
 312         struct tree *result, *next_tree, *base_tree, *head_tree;
 313         int clean, index_fd;
 314         static struct lock_file index_lock;
 315
 316         index_fd = hold_locked_index(&index_lock, 1);
 317
 318         read_cache();
 319         init_merge_options(&o);
 320         o.ancestor = base ? base_label : "(empty tree)";
 321         o.branch1 = "HEAD";
 322         o.branch2 = next ? next_label : "(empty tree)";
 323
 324         head_tree = parse_tree_indirect(head);
 325         next_tree = next ? next->tree : empty_tree();
 326         base_tree = base ? base->tree : empty_tree();
 327
 328         clean = merge_trees(&o,
 329                             head_tree,
 330                             next_tree, base_tree, &result);
 331
 332         if (active_cache_changed &&
 333             (write_cache(index_fd, active_cache, active_nr) ||
 334              commit_locked_index(&index_lock)))
 335                 die("%s: Unable to write new index file", me);
 336         rollback_lock_file(&index_lock);
 337
 338         if (!clean) {
 339                 int i;
 340                 strbuf_addstr(msgbuf, "\nConflicts:\n\n");
 341                 for (i = 0; i < active_nr;) {
 342                         struct cache_entry *ce = active_cache[i++];
 343                         if (ce_stage(ce)) {
 344                                 strbuf_addch(msgbuf, '\t');
 345                                 strbuf_addstr(msgbuf, ce->name);
 346                                 strbuf_addch(msgbuf, '\n');
 347                                 while (i < active_nr && !strcmp(ce->name,
 348                                                 active_cache[i]->name))
 349                                         i++;
 350                         }
 351                 }
 352                 write_message(msgbuf, defmsg);
 353                 fprintf(stderr, "Automatic %s failed.%s\n",
 354                         me, help_msg(commit_name));
 355                 rerere(allow_rerere_auto);
 356                 exit(1);
 357         }
 358         write_message(msgbuf, defmsg);
 359         fprintf(stderr, "Finished one %s.\n", me);
 360 }
 361
 362 static int do_pick_commit(void)
 363 {
 364         unsigned char head[20];
 365         struct commit *base, *next, *parent;
 366         const char *base_label, *next_label;
 367         struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
 368         char *defmsg = NULL;
 369         struct strbuf msgbuf = STRBUF_INIT;
 370
 371         if (no_commit) {
 372                 /*
 373                  * We do not intend to commit immediately.  We just want to
 374                  * merge the differences in, so let's compute the tree
 375                  * that represents the "current" state for merge-recursive
 376                  * to work on.
 377                  */
 378                 if (write_cache_as_tree(head, 0, NULL))
 379                         die ("Your index file is unmerged.");
 380         } else {
 381                 if (get_sha1("HEAD", head))
 382                         die ("You do not have a valid HEAD");
 383                 if (index_differs_from("HEAD", 0))
 384                         die_dirty_index(me);
 385         }
 386         discard_cache();
 387
 388         if (!commit->parents) {
 389                 if (action == REVERT)
 390                         die ("Cannot revert a root commit");
 391                 parent = NULL;
 392         }
 393         else if (commit->parents->next) {
 394                 /* Reverting or cherry-picking a merge commit */
 395                 int cnt;
 396                 struct commit_list *p;
 397
 398                 if (!mainline)
 399                         die("Commit %s is a merge but no -m option was given.",
 400                             sha1_to_hex(commit->object.sha1));
 401
 402                 for (cnt = 1, p = commit->parents;
 403                      cnt != mainline && p;
 404                      cnt++)
 405                         p = p->next;
 406                 if (cnt != mainline || !p)
 407                         die("Commit %s does not have parent %d",
 408                             sha1_to_hex(commit->object.sha1), mainline);
 409                 parent = p->item;
 410         } else if (0 < mainline)
 411                 die("Mainline was specified but commit %s is not a merge.",
 412                     sha1_to_hex(commit->object.sha1));
 413         else
 414                 parent = commit->parents->item;
 415
 416         if (allow_ff && !hashcmp(parent->object.sha1, head))
 417                 return fast_forward_to(commit->object.sha1, head);
 418
 419         if (parent && parse_commit(parent) < 0)
 420                 die("%s: cannot parse parent commit %s",
 421                     me, sha1_to_hex(parent->object.sha1));
 422
 423         if (get_message(commit->buffer, &msg) != 0)
 424                 die("Cannot get commit message for %s",
 425                                 sha1_to_hex(commit->object.sha1));
 426
 427         /*
 428          * "commit" is an existing commit.  We would want to apply
 429          * the difference it introduces since its first parent "prev"
 430          * on top of the current HEAD if we are cherry-pick.  Or the
 431          * reverse of it if we are revert.
 432          */
 433
 434         defmsg = git_pathdup("MERGE_MSG");
 435
 436         if (action == REVERT) {
 437                 base = commit;
 438                 base_label = msg.label;
 439                 next = parent;
 440                 next_label = msg.parent_label;
 441                 strbuf_addstr(&msgbuf, "Revert \"");
 442                 strbuf_addstr(&msgbuf, msg.subject);
 443                 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
 444                 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 445
 446                 if (commit->parents->next) {
 447                         strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
 448                         strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
 449                 }
 450                 strbuf_addstr(&msgbuf, ".\n");
 451         } else {
 452                 base = parent;
 453                 base_label = msg.parent_label;
 454                 next = commit;
 455                 next_label = msg.label;
 456                 set_author_ident_env(msg.message);
 457                 add_message_to_msg(&msgbuf, msg.message);
 458                 if (no_replay) {
 459                         strbuf_addstr(&msgbuf, "(cherry picked from commit ");
 460                         strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 461                         strbuf_addstr(&msgbuf, ")\n");
 462                 }
 463         }
 464
 465         if (!strategy || !strcmp(strategy, "recursive") || action == REVERT)
 466                 do_recursive_merge(base, next, base_label, next_label,
 467                                    head, &msgbuf, defmsg);
 468         else {
 469                 int res;
 470                 struct commit_list *common = NULL;
 471                 struct commit_list *remotes = NULL;
 472                 write_message(&msgbuf, defmsg);
 473                 commit_list_insert(base, &common);
 474                 commit_list_insert(next, &remotes);
 475                 res = try_merge_command(strategy, common,
 476                                         sha1_to_hex(head), remotes);
 477                 free_commit_list(common);
 478                 free_commit_list(remotes);
 479                 if (res) {
 480                         fprintf(stderr, "Automatic %s with strategy %s failed.%s\n",
 481                                 me, strategy, help_msg(commit_name));
 482                         rerere(allow_rerere_auto);
 483                         exit(1);
 484                 }
 485         }
 486
 487         /*
 488          *
 489          * If we are cherry-pick, and if the merge did not result in
 490          * hand-editing, we will hit this commit and inherit the original
 491          * author date and name.
 492          * If we are revert, or if our cherry-pick results in a hand merge,
 493          * we had better say that the current user is responsible for that.
 494          */
 495
 496         if (!no_commit) {
 497                 /* 6 is max possible length of our args array including NULL */
 498                 const char *args[6];
 499                 int i = 0;
 500                 args[i++] = "commit";
 501                 args[i++] = "-n";
 502                 if (signoff)
 503                         args[i++] = "-s";
 504                 if (!edit) {
 505                         args[i++] = "-F";
 506                         args[i++] = defmsg;
 507                 }
 508                 args[i] = NULL;
 509                 return run_command_v_opt(args, RUN_GIT_CMD);
 510         }
 511         free_message(&msg);
 512         free(defmsg);
 513
 514         return 0;
 515 }
 516
 517 static int revert_or_cherry_pick(int argc, const char **argv)
 518 {
 519         const char *dotdot;
 520         unsigned char sha1[20];
 521
 522         git_config(git_default_config, NULL);
 523         me = action == REVERT ? "revert" : "cherry-pick";
 524         setenv(GIT_REFLOG_ACTION, me, 0);
 525         parse_args(argc, argv);
 526
 527         /* this is copied from the shell script, but it's never triggered... */
 528         if (action == REVERT && !no_replay)
 529                 die("revert is incompatible with replay");
 530
 531         if (allow_ff) {
 532                 if (signoff)
 533                         die("cherry-pick --ff cannot be used with --signoff");
 534                 if (no_commit)
 535                         die("cherry-pick --ff cannot be used with --no-commit");
 536                 if (no_replay)
 537                         die("cherry-pick --ff cannot be used with -x");
 538                 if (edit)
 539                         die("cherry-pick --ff cannot be used with --edit");
 540         }
 541
 542         if (read_cache() < 0)
 543                 die("git %s: failed to read the index", me);
 544
 545         dotdot = strstr(commit_name, "..");
 546         if (dotdot) {
 547                 struct rev_info revs;
 548                 const char *argv[4];
 549                 int argc = 0;
 550
 551                 argv[argc++] = NULL;
 552                 if (action != REVERT)
 553                         argv[argc++] = "--reverse";
 554                 argv[argc++] = commit_name;
 555                 argv[argc++] = NULL;
 556
 557                 init_revisions(&revs, NULL);
 558                 setup_revisions(argc - 1, argv, &revs, NULL);
 559                 if (prepare_revision_walk(&revs))
 560                         die("revision walk setup failed");
 561
 562                 if (!revs.commits)
 563                         die("empty range passed");
 564
 565                 while ( (commit = get_revision(&revs)) ) {
 566                         int res = do_pick_commit();
 567                         if (res)
 568                                 return res;
 569                 }
 570                 return 0;
 571         }
 572
 573         if (get_sha1(commit_name, sha1))
 574                 die ("Cannot find '%s'", commit_name);
 575         commit = lookup_commit_reference(sha1);
 576         if (!commit)
 577                 exit(1);
 578
 579         return do_pick_commit();
 580 }
 581
 582 int cmd_revert(int argc, const char **argv, const char *prefix)
 583 {
 584         if (isatty(0))
 585                 edit = 1;
 586         no_replay = 1;
 587         action = REVERT;
 588         return revert_or_cherry_pick(argc, argv);
 589 }
 590
 591 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
 592 {
 593         no_replay = 0;
 594         action = CHERRY_PICK;
 595         return revert_or_cherry_pick(argc, argv);
 596 }