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
  47 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
  48
  49 static void parse_args(int argc, const char **argv)
  50 {
  51         const char * const * usage_str =
  52                 action == REVERT ?  revert_usage : cherry_pick_usage;
  53         unsigned char sha1[20];
  54         int noop;
  55         struct option options[] = {
  56                 OPT_BOOLEAN('n', "no-commit", &no_commit, "don't automatically commit"),
  57                 OPT_BOOLEAN('e', "edit", &edit, "edit the commit message"),
  58                 OPT_BOOLEAN('x', NULL, &no_replay, "append commit name when cherry-picking"),
  59                 OPT_BOOLEAN('r', NULL, &noop, "no-op (backward compatibility)"),
  60                 OPT_BOOLEAN('s', "signoff", &signoff, "add Signed-off-by:"),
  61                 OPT_INTEGER('m', "mainline", &mainline, "parent number"),
  62                 OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
  63                 OPT_END(),
  64                 OPT_END(),
  65                 OPT_END(),
  66         };
  67
  68         if (action == CHERRY_PICK) {
  69                 struct option cp_extra[] = {
  70                         OPT_BOOLEAN(0, "ff", &allow_ff, "allow fast-forward"),
  71                         OPT_END(),
  72                 };
  73                 if (parse_options_concat(options, ARRAY_SIZE(options), cp_extra))
  74                         die("program error");
  75         }
  76
  77         if (parse_options(argc, argv, NULL, options, usage_str, 0) != 1)
  78                 usage_with_options(usage_str, options);
  79
  80         commit_name = argv[0];
  81         if (get_sha1(commit_name, sha1))
  82                 die ("Cannot find '%s'", commit_name);
  83         commit = lookup_commit_reference(sha1);
  84         if (!commit)
  85                 exit(1);
  86 }
  87
  88 static char *get_oneline(const char *message)
  89 {
  90         char *result;
  91         const char *p = message, *abbrev, *eol;
  92         int abbrev_len, oneline_len;
  93
  94         if (!p)
  95                 die ("Could not read commit message of %s",
  96                                 sha1_to_hex(commit->object.sha1));
  97         while (*p && (*p != '\n' || p[1] != '\n'))
  98                 p++;
  99
 100         if (*p) {
 101                 p += 2;
 102                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
 103                         ; /* do nothing */
 104         } else
 105                 eol = p;
 106         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
 107         abbrev_len = strlen(abbrev);
 108         oneline_len = eol - p;
 109         result = xmalloc(abbrev_len + 5 + oneline_len);
 110         memcpy(result, abbrev, abbrev_len);
 111         memcpy(result + abbrev_len, "... ", 4);
 112         memcpy(result + abbrev_len + 4, p, oneline_len);
 113         result[abbrev_len + 4 + oneline_len] = '\0';
 114         return result;
 115 }
 116
 117 static char *get_encoding(const char *message)
 118 {
 119         const char *p = message, *eol;
 120
 121         if (!p)
 122                 die ("Could not read commit message of %s",
 123                                 sha1_to_hex(commit->object.sha1));
 124         while (*p && *p != '\n') {
 125                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
 126                         ; /* do nothing */
 127                 if (!prefixcmp(p, "encoding ")) {
 128                         char *result = xmalloc(eol - 8 - p);
 129                         strlcpy(result, p + 9, eol - 8 - p);
 130                         return result;
 131                 }
 132                 p = eol;
 133                 if (*p == '\n')
 134                         p++;
 135         }
 136         return NULL;
 137 }
 138
 139 static struct lock_file msg_file;
 140 static int msg_fd;
 141
 142 static void add_to_msg(const char *string)
 143 {
 144         int len = strlen(string);
 145         if (write_in_full(msg_fd, string, len) < 0)
 146                 die_errno ("Could not write to MERGE_MSG");
 147 }
 148
 149 static void add_message_to_msg(const char *message)
 150 {
 151         const char *p = message;
 152         while (*p && (*p != '\n' || p[1] != '\n'))
 153                 p++;
 154
 155         if (!*p)
 156                 add_to_msg(sha1_to_hex(commit->object.sha1));
 157
 158         p += 2;
 159         add_to_msg(p);
 160         return;
 161 }
 162
 163 static void set_author_ident_env(const char *message)
 164 {
 165         const char *p = message;
 166         if (!p)
 167                 die ("Could not read commit message of %s",
 168                                 sha1_to_hex(commit->object.sha1));
 169         while (*p && *p != '\n') {
 170                 const char *eol;
 171
 172                 for (eol = p; *eol && *eol != '\n'; eol++)
 173                         ; /* do nothing */
 174                 if (!prefixcmp(p, "author ")) {
 175                         char *line, *pend, *email, *timestamp;
 176
 177                         p += 7;
 178                         line = xmemdupz(p, eol - p);
 179                         email = strchr(line, '<');
 180                         if (!email)
 181                                 die ("Could not extract author email from %s",
 182                                         sha1_to_hex(commit->object.sha1));
 183                         if (email == line)
 184                                 pend = line;
 185                         else
 186                                 for (pend = email; pend != line + 1 &&
 187                                                 isspace(pend[-1]); pend--);
 188                                         ; /* do nothing */
 189                         *pend = '\0';
 190                         email++;
 191                         timestamp = strchr(email, '>');
 192                         if (!timestamp)
 193                                 die ("Could not extract author time from %s",
 194                                         sha1_to_hex(commit->object.sha1));
 195                         *timestamp = '\0';
 196                         for (timestamp++; *timestamp && isspace(*timestamp);
 197                                         timestamp++)
 198                                 ; /* do nothing */
 199                         setenv("GIT_AUTHOR_NAME", line, 1);
 200                         setenv("GIT_AUTHOR_EMAIL", email, 1);
 201                         setenv("GIT_AUTHOR_DATE", timestamp, 1);
 202                         free(line);
 203                         return;
 204                 }
 205                 p = eol;
 206                 if (*p == '\n')
 207                         p++;
 208         }
 209         die ("No author information found in %s",
 210                         sha1_to_hex(commit->object.sha1));
 211 }
 212
 213 static char *help_msg(const char *name)
 214 {
 215         struct strbuf helpbuf = STRBUF_INIT;
 216         char *msg = getenv("GIT_CHERRY_PICK_HELP");
 217
 218         if (msg)
 219                 return msg;
 220
 221         strbuf_addstr(&helpbuf, "  After resolving the conflicts,\n"
 222                 "mark the corrected paths with 'git add <paths>' or 'git rm <paths>'\n"
 223                 "and commit the result");
 224
 225         if (action == CHERRY_PICK) {
 226                 strbuf_addf(&helpbuf, " with: \n"
 227                         "\n"
 228                         "        git commit -c %s\n",
 229                         name);
 230         }
 231         else
 232                 strbuf_addch(&helpbuf, '.');
 233         return strbuf_detach(&helpbuf, NULL);
 234 }
 235
 236 static struct tree *empty_tree(void)
 237 {
 238         struct tree *tree = xcalloc(1, sizeof(struct tree));
 239
 240         tree->object.parsed = 1;
 241         tree->object.type = OBJ_TREE;
 242         pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
 243         return tree;
 244 }
 245
 246 static NORETURN void die_dirty_index(const char *me)
 247 {
 248         if (read_cache_unmerged()) {
 249                 die_resolve_conflict(me);
 250         } else {
 251                 if (advice_commit_before_merge)
 252                         die("Your local changes would be overwritten by %s.\n"
 253                             "Please, commit your changes or stash them to proceed.", me);
 254                 else
 255                         die("Your local changes would be overwritten by %s.\n", me);
 256         }
 257 }
 258
 259 static int fast_forward_to(const unsigned char *to, const unsigned char *from)
 260 {
 261         struct ref_lock *ref_lock;
 262
 263         read_cache();
 264         if (checkout_fast_forward(from, to))
 265                 exit(1); /* the callee should have complained already */
 266         ref_lock = lock_any_ref_for_update("HEAD", from, 0);
 267         return write_ref_sha1(ref_lock, to, "cherry-pick");
 268 }
 269
 270 static int revert_or_cherry_pick(int argc, const char **argv)
 271 {
 272         unsigned char head[20];
 273         struct commit *base, *next, *parent;
 274         int i, index_fd, clean;
 275         char *oneline, *reencoded_message = NULL;
 276         const char *message, *encoding;
 277         char *defmsg = NULL;
 278         struct merge_options o;
 279         struct tree *result, *next_tree, *base_tree, *head_tree;
 280         static struct lock_file index_lock;
 281
 282         git_config(git_default_config, NULL);
 283         me = action == REVERT ? "revert" : "cherry-pick";
 284         setenv(GIT_REFLOG_ACTION, me, 0);
 285         parse_args(argc, argv);
 286
 287         /* this is copied from the shell script, but it's never triggered... */
 288         if (action == REVERT && !no_replay)
 289                 die("revert is incompatible with replay");
 290
 291         if (allow_ff) {
 292                 if (signoff)
 293                         die("cherry-pick --ff cannot be used with --signoff");
 294                 if (no_commit)
 295                         die("cherry-pick --ff cannot be used with --no-commit");
 296                 if (no_replay)
 297                         die("cherry-pick --ff cannot be used with -x");
 298                 if (edit)
 299                         die("cherry-pick --ff cannot be used with --edit");
 300         }
 301
 302         if (read_cache() < 0)
 303                 die("git %s: failed to read the index", me);
 304         if (no_commit) {
 305                 /*
 306                  * We do not intend to commit immediately.  We just want to
 307                  * merge the differences in, so let's compute the tree
 308                  * that represents the "current" state for merge-recursive
 309                  * to work on.
 310                  */
 311                 if (write_cache_as_tree(head, 0, NULL))
 312                         die ("Your index file is unmerged.");
 313         } else {
 314                 if (get_sha1("HEAD", head))
 315                         die ("You do not have a valid HEAD");
 316                 if (index_differs_from("HEAD", 0))
 317                         die_dirty_index(me);
 318         }
 319         discard_cache();
 320
 321         if (!commit->parents) {
 322                 if (action == REVERT)
 323                         die ("Cannot revert a root commit");
 324                 parent = NULL;
 325         }
 326         else if (commit->parents->next) {
 327                 /* Reverting or cherry-picking a merge commit */
 328                 int cnt;
 329                 struct commit_list *p;
 330
 331                 if (!mainline)
 332                         die("Commit %s is a merge but no -m option was given.",
 333                             sha1_to_hex(commit->object.sha1));
 334
 335                 for (cnt = 1, p = commit->parents;
 336                      cnt != mainline && p;
 337                      cnt++)
 338                         p = p->next;
 339                 if (cnt != mainline || !p)
 340                         die("Commit %s does not have parent %d",
 341                             sha1_to_hex(commit->object.sha1), mainline);
 342                 parent = p->item;
 343         } else if (0 < mainline)
 344                 die("Mainline was specified but commit %s is not a merge.",
 345                     sha1_to_hex(commit->object.sha1));
 346         else
 347                 parent = commit->parents->item;
 348
 349         if (allow_ff && !hashcmp(parent->object.sha1, head))
 350                 return fast_forward_to(commit->object.sha1, head);
 351
 352         if (!(message = commit->buffer))
 353                 die ("Cannot get commit message for %s",
 354                                 sha1_to_hex(commit->object.sha1));
 355
 356         if (parent && parse_commit(parent) < 0)
 357                 die("%s: cannot parse parent commit %s",
 358                     me, sha1_to_hex(parent->object.sha1));
 359
 360         /*
 361          * "commit" is an existing commit.  We would want to apply
 362          * the difference it introduces since its first parent "prev"
 363          * on top of the current HEAD if we are cherry-pick.  Or the
 364          * reverse of it if we are revert.
 365          */
 366
 367         defmsg = git_pathdup("MERGE_MSG");
 368         msg_fd = hold_lock_file_for_update(&msg_file, defmsg,
 369                                            LOCK_DIE_ON_ERROR);
 370
 371         encoding = get_encoding(message);
 372         if (!encoding)
 373                 encoding = "UTF-8";
 374         if (!git_commit_encoding)
 375                 git_commit_encoding = "UTF-8";
 376         if ((reencoded_message = reencode_string(message,
 377                                         git_commit_encoding, encoding)))
 378                 message = reencoded_message;
 379
 380         oneline = get_oneline(message);
 381
 382         index_fd = hold_locked_index(&index_lock, 1);
 383
 384         if (action == REVERT) {
 385                 char *oneline_body = strchr(oneline, ' ');
 386
 387                 base = commit;
 388                 next = parent;
 389                 add_to_msg("Revert \"");
 390                 add_to_msg(oneline_body + 1);
 391                 add_to_msg("\"\n\nThis reverts commit ");
 392                 add_to_msg(sha1_to_hex(commit->object.sha1));
 393
 394                 if (commit->parents->next) {
 395                         add_to_msg(", reversing\nchanges made to ");
 396                         add_to_msg(sha1_to_hex(parent->object.sha1));
 397                 }
 398                 add_to_msg(".\n");
 399         } else {
 400                 base = parent;
 401                 next = commit;
 402                 set_author_ident_env(message);
 403                 add_message_to_msg(message);
 404                 if (no_replay) {
 405                         add_to_msg("(cherry picked from commit ");
 406                         add_to_msg(sha1_to_hex(commit->object.sha1));
 407                         add_to_msg(")\n");
 408                 }
 409         }
 410
 411         read_cache();
 412         init_merge_options(&o);
 413         o.branch1 = "HEAD";
 414         o.branch2 = oneline;
 415
 416         head_tree = parse_tree_indirect(head);
 417         next_tree = next ? next->tree : empty_tree();
 418         base_tree = base ? base->tree : empty_tree();
 419
 420         clean = merge_trees(&o,
 421                             head_tree,
 422                             next_tree, base_tree, &result);
 423
 424         if (active_cache_changed &&
 425             (write_cache(index_fd, active_cache, active_nr) ||
 426              commit_locked_index(&index_lock)))
 427                 die("%s: Unable to write new index file", me);
 428         rollback_lock_file(&index_lock);
 429
 430         if (!clean) {
 431                 add_to_msg("\nConflicts:\n\n");
 432                 for (i = 0; i < active_nr;) {
 433                         struct cache_entry *ce = active_cache[i++];
 434                         if (ce_stage(ce)) {
 435                                 add_to_msg("\t");
 436                                 add_to_msg(ce->name);
 437                                 add_to_msg("\n");
 438                                 while (i < active_nr && !strcmp(ce->name,
 439                                                 active_cache[i]->name))
 440                                         i++;
 441                         }
 442                 }
 443                 if (commit_lock_file(&msg_file) < 0)
 444                         die ("Error wrapping up %s", defmsg);
 445                 fprintf(stderr, "Automatic %s failed.%s\n",
 446                         me, help_msg(commit_name));
 447                 rerere(allow_rerere_auto);
 448                 exit(1);
 449         }
 450         if (commit_lock_file(&msg_file) < 0)
 451                 die ("Error wrapping up %s", defmsg);
 452         fprintf(stderr, "Finished one %s.\n", me);
 453
 454         /*
 455          *
 456          * If we are cherry-pick, and if the merge did not result in
 457          * hand-editing, we will hit this commit and inherit the original
 458          * author date and name.
 459          * If we are revert, or if our cherry-pick results in a hand merge,
 460          * we had better say that the current user is responsible for that.
 461          */
 462
 463         if (!no_commit) {
 464                 /* 6 is max possible length of our args array including NULL */
 465                 const char *args[6];
 466                 int i = 0;
 467                 args[i++] = "commit";
 468                 args[i++] = "-n";
 469                 if (signoff)
 470                         args[i++] = "-s";
 471                 if (!edit) {
 472                         args[i++] = "-F";
 473                         args[i++] = defmsg;
 474                 }
 475                 args[i] = NULL;
 476                 return execv_git_cmd(args);
 477         }
 478         free(reencoded_message);
 479         free(defmsg);
 480
 481         return 0;
 482 }
 483
 484 int cmd_revert(int argc, const char **argv, const char *prefix)
 485 {
 486         if (isatty(0))
 487                 edit = 1;
 488         no_replay = 1;
 489         action = REVERT;
 490         return revert_or_cherry_pick(argc, argv);
 491 }
 492
 493 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
 494 {
 495         no_replay = 0;
 496         action = CHERRY_PICK;
 497         return revert_or_cherry_pick(argc, argv);
 498 }