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
  17 /*
  18  * This implements the builtins revert and cherry-pick.
  19  *
  20  * Copyright (c) 2007 Johannes E. Schindelin
  21  *
  22  * Based on git-revert.sh, which is
  23  *
  24  * Copyright (c) 2005 Linus Torvalds
  25  * Copyright (c) 2005 Junio C Hamano
  26  */
  27
  28 static const char * const revert_usage[] = {
  29         "git revert [options] <commit-ish>",
  30         NULL
  31 };
  32
  33 static const char * const cherry_pick_usage[] = {
  34         "git cherry-pick [options] <commit-ish>",
  35         NULL
  36 };
  37
  38 static int edit, no_replay, no_commit, mainline, signoff;
  39 static enum { REVERT, CHERRY_PICK } action;
  40 static struct commit *commit;
  41 static int allow_rerere_auto;
  42
  43 static const char *me;
  44
  45 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
  46
  47 static void parse_args(int argc, const char **argv)
  48 {
  49         const char * const * usage_str =
  50                 action == REVERT ?  revert_usage : cherry_pick_usage;
  51         unsigned char sha1[20];
  52         const char *arg;
  53         int noop;
  54         struct option options[] = {
  55                 OPT_BOOLEAN('n', "no-commit", &no_commit, "don't automatically commit"),
  56                 OPT_BOOLEAN('e', "edit", &edit, "edit the commit message"),
  57                 OPT_BOOLEAN('x', NULL, &no_replay, "append commit name when cherry-picking"),
  58                 OPT_BOOLEAN('r', NULL, &noop, "no-op (backward compatibility)"),
  59                 OPT_BOOLEAN('s', "signoff", &signoff, "add Signed-off-by:"),
  60                 OPT_INTEGER('m', "mainline", &mainline, "parent number"),
  61                 OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
  62                 OPT_END(),
  63         };
  64
  65         if (parse_options(argc, argv, NULL, options, usage_str, 0) != 1)
  66                 usage_with_options(usage_str, options);
  67         arg = argv[0];
  68
  69         if (get_sha1(arg, sha1))
  70                 die ("Cannot find '%s'", arg);
  71         commit = (struct commit *)parse_object(sha1);
  72         if (!commit)
  73                 die ("Could not find %s", sha1_to_hex(sha1));
  74         if (commit->object.type == OBJ_TAG) {
  75                 commit = (struct commit *)
  76                         deref_tag((struct object *)commit, arg, strlen(arg));
  77         }
  78         if (commit->object.type != OBJ_COMMIT)
  79                 die ("'%s' does not point to a commit", arg);
  80 }
  81
  82 static char *get_oneline(const char *message)
  83 {
  84         char *result;
  85         const char *p = message, *abbrev, *eol;
  86         int abbrev_len, oneline_len;
  87
  88         if (!p)
  89                 die ("Could not read commit message of %s",
  90                                 sha1_to_hex(commit->object.sha1));
  91         while (*p && (*p != '\n' || p[1] != '\n'))
  92                 p++;
  93
  94         if (*p) {
  95                 p += 2;
  96                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
  97                         ; /* do nothing */
  98         } else
  99                 eol = p;
 100         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
 101         abbrev_len = strlen(abbrev);
 102         oneline_len = eol - p;
 103         result = xmalloc(abbrev_len + 5 + oneline_len);
 104         memcpy(result, abbrev, abbrev_len);
 105         memcpy(result + abbrev_len, "... ", 4);
 106         memcpy(result + abbrev_len + 4, p, oneline_len);
 107         result[abbrev_len + 4 + oneline_len] = '\0';
 108         return result;
 109 }
 110
 111 static char *get_encoding(const char *message)
 112 {
 113         const char *p = message, *eol;
 114
 115         if (!p)
 116                 die ("Could not read commit message of %s",
 117                                 sha1_to_hex(commit->object.sha1));
 118         while (*p && *p != '\n') {
 119                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
 120                         ; /* do nothing */
 121                 if (!prefixcmp(p, "encoding ")) {
 122                         char *result = xmalloc(eol - 8 - p);
 123                         strlcpy(result, p + 9, eol - 8 - p);
 124                         return result;
 125                 }
 126                 p = eol;
 127                 if (*p == '\n')
 128                         p++;
 129         }
 130         return NULL;
 131 }
 132
 133 static struct lock_file msg_file;
 134 static int msg_fd;
 135
 136 static void add_to_msg(const char *string)
 137 {
 138         int len = strlen(string);
 139         if (write_in_full(msg_fd, string, len) < 0)
 140                 die_errno ("Could not write to MERGE_MSG");
 141 }
 142
 143 static void add_message_to_msg(const char *message)
 144 {
 145         const char *p = message;
 146         while (*p && (*p != '\n' || p[1] != '\n'))
 147                 p++;
 148
 149         if (!*p)
 150                 add_to_msg(sha1_to_hex(commit->object.sha1));
 151
 152         p += 2;
 153         add_to_msg(p);
 154         return;
 155 }
 156
 157 static void set_author_ident_env(const char *message)
 158 {
 159         const char *p = message;
 160         if (!p)
 161                 die ("Could not read commit message of %s",
 162                                 sha1_to_hex(commit->object.sha1));
 163         while (*p && *p != '\n') {
 164                 const char *eol;
 165
 166                 for (eol = p; *eol && *eol != '\n'; eol++)
 167                         ; /* do nothing */
 168                 if (!prefixcmp(p, "author ")) {
 169                         char *line, *pend, *email, *timestamp;
 170
 171                         p += 7;
 172                         line = xmemdupz(p, eol - p);
 173                         email = strchr(line, '<');
 174                         if (!email)
 175                                 die ("Could not extract author email from %s",
 176                                         sha1_to_hex(commit->object.sha1));
 177                         if (email == line)
 178                                 pend = line;
 179                         else
 180                                 for (pend = email; pend != line + 1 &&
 181                                                 isspace(pend[-1]); pend--);
 182                                         ; /* do nothing */
 183                         *pend = '\0';
 184                         email++;
 185                         timestamp = strchr(email, '>');
 186                         if (!timestamp)
 187                                 die ("Could not extract author time from %s",
 188                                         sha1_to_hex(commit->object.sha1));
 189                         *timestamp = '\0';
 190                         for (timestamp++; *timestamp && isspace(*timestamp);
 191                                         timestamp++)
 192                                 ; /* do nothing */
 193                         setenv("GIT_AUTHOR_NAME", line, 1);
 194                         setenv("GIT_AUTHOR_EMAIL", email, 1);
 195                         setenv("GIT_AUTHOR_DATE", timestamp, 1);
 196                         free(line);
 197                         return;
 198                 }
 199                 p = eol;
 200                 if (*p == '\n')
 201                         p++;
 202         }
 203         die ("No author information found in %s",
 204                         sha1_to_hex(commit->object.sha1));
 205 }
 206
 207 static char *help_msg(const unsigned char *sha1)
 208 {
 209         static char helpbuf[1024];
 210         char *msg = getenv("GIT_CHERRY_PICK_HELP");
 211
 212         if (msg)
 213                 return msg;
 214
 215         strcpy(helpbuf, "  After resolving the conflicts,\n"
 216                 "mark the corrected paths with 'git add <paths>' or 'git rm <paths>'\n"
 217                 "and commit the result.");
 218
 219         if (action == CHERRY_PICK) {
 220                 sprintf(helpbuf + strlen(helpbuf),
 221                         "  When committing, use the option '-c %s'\n"
 222                         "to retain authorship and message.",
 223                         find_unique_abbrev(sha1, DEFAULT_ABBREV));
 224         }
 225         return helpbuf;
 226 }
 227
 228 static struct tree *empty_tree(void)
 229 {
 230         struct tree *tree = xcalloc(1, sizeof(struct tree));
 231
 232         tree->object.parsed = 1;
 233         tree->object.type = OBJ_TREE;
 234         pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
 235         return tree;
 236 }
 237
 238 static NORETURN void die_dirty_index(const char *me)
 239 {
 240         if (read_cache_unmerged()) {
 241                 die_resolve_conflict(me);
 242         } else {
 243                 if (advice_commit_before_merge)
 244                         die("Your local changes would be overwritten by %s.\n"
 245                             "Please, commit your changes or stash them to proceed.", me);
 246                 else
 247                         die("Your local changes would be overwritten by %s.\n", me);
 248         }
 249 }
 250
 251 static int revert_or_cherry_pick(int argc, const char **argv)
 252 {
 253         unsigned char head[20];
 254         struct commit *base, *next, *parent;
 255         int i, index_fd, clean;
 256         char *oneline, *reencoded_message = NULL;
 257         const char *message, *encoding;
 258         char *defmsg = git_pathdup("MERGE_MSG");
 259         struct merge_options o;
 260         struct tree *result, *next_tree, *base_tree, *head_tree;
 261         static struct lock_file index_lock;
 262
 263         git_config(git_default_config, NULL);
 264         me = action == REVERT ? "revert" : "cherry-pick";
 265         setenv(GIT_REFLOG_ACTION, me, 0);
 266         parse_args(argc, argv);
 267
 268         /* this is copied from the shell script, but it's never triggered... */
 269         if (action == REVERT && !no_replay)
 270                 die("revert is incompatible with replay");
 271
 272         if (read_cache() < 0)
 273                 die("git %s: failed to read the index", me);
 274         if (no_commit) {
 275                 /*
 276                  * We do not intend to commit immediately.  We just want to
 277                  * merge the differences in, so let's compute the tree
 278                  * that represents the "current" state for merge-recursive
 279                  * to work on.
 280                  */
 281                 if (write_cache_as_tree(head, 0, NULL))
 282                         die ("Your index file is unmerged.");
 283         } else {
 284                 if (get_sha1("HEAD", head))
 285                         die ("You do not have a valid HEAD");
 286                 if (index_differs_from("HEAD", 0))
 287                         die_dirty_index(me);
 288         }
 289         discard_cache();
 290
 291         index_fd = hold_locked_index(&index_lock, 1);
 292
 293         if (!commit->parents) {
 294                 if (action == REVERT)
 295                         die ("Cannot revert a root commit");
 296                 parent = NULL;
 297         }
 298         else if (commit->parents->next) {
 299                 /* Reverting or cherry-picking a merge commit */
 300                 int cnt;
 301                 struct commit_list *p;
 302
 303                 if (!mainline)
 304                         die("Commit %s is a merge but no -m option was given.",
 305                             sha1_to_hex(commit->object.sha1));
 306
 307                 for (cnt = 1, p = commit->parents;
 308                      cnt != mainline && p;
 309                      cnt++)
 310                         p = p->next;
 311                 if (cnt != mainline || !p)
 312                         die("Commit %s does not have parent %d",
 313                             sha1_to_hex(commit->object.sha1), mainline);
 314                 parent = p->item;
 315         } else if (0 < mainline)
 316                 die("Mainline was specified but commit %s is not a merge.",
 317                     sha1_to_hex(commit->object.sha1));
 318         else
 319                 parent = commit->parents->item;
 320
 321         if (!(message = commit->buffer))
 322                 die ("Cannot get commit message for %s",
 323                                 sha1_to_hex(commit->object.sha1));
 324
 325         if (parent && parse_commit(parent) < 0)
 326                 die("%s: cannot parse parent commit %s",
 327                     me, sha1_to_hex(parent->object.sha1));
 328
 329         /*
 330          * "commit" is an existing commit.  We would want to apply
 331          * the difference it introduces since its first parent "prev"
 332          * on top of the current HEAD if we are cherry-pick.  Or the
 333          * reverse of it if we are revert.
 334          */
 335
 336         msg_fd = hold_lock_file_for_update(&msg_file, defmsg,
 337                                            LOCK_DIE_ON_ERROR);
 338
 339         encoding = get_encoding(message);
 340         if (!encoding)
 341                 encoding = "UTF-8";
 342         if (!git_commit_encoding)
 343                 git_commit_encoding = "UTF-8";
 344         if ((reencoded_message = reencode_string(message,
 345                                         git_commit_encoding, encoding)))
 346                 message = reencoded_message;
 347
 348         oneline = get_oneline(message);
 349
 350         if (action == REVERT) {
 351                 char *oneline_body = strchr(oneline, ' ');
 352
 353                 base = commit;
 354                 next = parent;
 355                 add_to_msg("Revert \"");
 356                 add_to_msg(oneline_body + 1);
 357                 add_to_msg("\"\n\nThis reverts commit ");
 358                 add_to_msg(sha1_to_hex(commit->object.sha1));
 359
 360                 if (commit->parents->next) {
 361                         add_to_msg(", reversing\nchanges made to ");
 362                         add_to_msg(sha1_to_hex(parent->object.sha1));
 363                 }
 364                 add_to_msg(".\n");
 365         } else {
 366                 base = parent;
 367                 next = commit;
 368                 set_author_ident_env(message);
 369                 add_message_to_msg(message);
 370                 if (no_replay) {
 371                         add_to_msg("(cherry picked from commit ");
 372                         add_to_msg(sha1_to_hex(commit->object.sha1));
 373                         add_to_msg(")\n");
 374                 }
 375         }
 376
 377         read_cache();
 378         init_merge_options(&o);
 379         o.branch1 = "HEAD";
 380         o.branch2 = oneline;
 381
 382         head_tree = parse_tree_indirect(head);
 383         next_tree = next ? next->tree : empty_tree();
 384         base_tree = base ? base->tree : empty_tree();
 385
 386         clean = merge_trees(&o,
 387                             head_tree,
 388                             next_tree, base_tree, &result);
 389
 390         if (active_cache_changed &&
 391             (write_cache(index_fd, active_cache, active_nr) ||
 392              commit_locked_index(&index_lock)))
 393                 die("%s: Unable to write new index file", me);
 394         rollback_lock_file(&index_lock);
 395
 396         if (!clean) {
 397                 add_to_msg("\nConflicts:\n\n");
 398                 for (i = 0; i < active_nr;) {
 399                         struct cache_entry *ce = active_cache[i++];
 400                         if (ce_stage(ce)) {
 401                                 add_to_msg("\t");
 402                                 add_to_msg(ce->name);
 403                                 add_to_msg("\n");
 404                                 while (i < active_nr && !strcmp(ce->name,
 405                                                 active_cache[i]->name))
 406                                         i++;
 407                         }
 408                 }
 409                 if (commit_lock_file(&msg_file) < 0)
 410                         die ("Error wrapping up %s", defmsg);
 411                 fprintf(stderr, "Automatic %s failed.%s\n",
 412                         me, help_msg(commit->object.sha1));
 413                 rerere(allow_rerere_auto);
 414                 exit(1);
 415         }
 416         if (commit_lock_file(&msg_file) < 0)
 417                 die ("Error wrapping up %s", defmsg);
 418         fprintf(stderr, "Finished one %s.\n", me);
 419
 420         /*
 421          *
 422          * If we are cherry-pick, and if the merge did not result in
 423          * hand-editing, we will hit this commit and inherit the original
 424          * author date and name.
 425          * If we are revert, or if our cherry-pick results in a hand merge,
 426          * we had better say that the current user is responsible for that.
 427          */
 428
 429         if (!no_commit) {
 430                 /* 6 is max possible length of our args array including NULL */
 431                 const char *args[6];
 432                 int i = 0;
 433                 args[i++] = "commit";
 434                 args[i++] = "-n";
 435                 if (signoff)
 436                         args[i++] = "-s";
 437                 if (!edit) {
 438                         args[i++] = "-F";
 439                         args[i++] = defmsg;
 440                 }
 441                 args[i] = NULL;
 442                 return execv_git_cmd(args);
 443         }
 444         free(reencoded_message);
 445         free(defmsg);
 446
 447         return 0;
 448 }
 449
 450 int cmd_revert(int argc, const char **argv, const char *prefix)
 451 {
 452         if (isatty(0))
 453                 edit = 1;
 454         no_replay = 1;
 455         action = REVERT;
 456         return revert_or_cherry_pick(argc, argv);
 457 }
 458
 459 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
 460 {
 461         no_replay = 0;
 462         action = CHERRY_PICK;
 463         return revert_or_cherry_pick(argc, argv);
 464 }