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 const char *commit_name;
  42 static int allow_rerere_auto;
  43
  44 static const char *me;
  45 static const char *strategy;
  46
  47 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
  48
  49 static char *get_encoding(const char *message);
  50
  51 static void parse_args(int argc, const char **argv)
  52 {
  53         const char * const * usage_str =
  54                 action == REVERT ?  revert_usage : cherry_pick_usage;
  55         unsigned char sha1[20];
  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         };
  68
  69         if (parse_options(argc, argv, NULL, options, usage_str, 0) != 1)
  70                 usage_with_options(usage_str, options);
  71
  72         commit_name = argv[0];
  73         if (get_sha1(commit_name, sha1))
  74                 die ("Cannot find '%s'", commit_name);
  75         commit = lookup_commit_reference(sha1);
  76         if (!commit)
  77                 exit(1);
  78 }
  79
  80 struct commit_message {
  81         char *parent_label;
  82         const char *label;
  83         const char *subject;
  84         char *reencoded_message;
  85         const char *message;
  86 };
  87
  88 static int get_message(const char *raw_message, struct commit_message *out)
  89 {
  90         const char *encoding;
  91         const char *p, *abbrev, *eol;
  92         char *q;
  93         int abbrev_len, oneline_len;
  94
  95         if (!raw_message)
  96                 return -1;
  97         encoding = get_encoding(raw_message);
  98         if (!encoding)
  99                 encoding = "UTF-8";
 100         if (!git_commit_encoding)
 101                 git_commit_encoding = "UTF-8";
 102         if ((out->reencoded_message = reencode_string(raw_message,
 103                                         git_commit_encoding, encoding)))
 104                 out->message = out->reencoded_message;
 105
 106         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
 107         abbrev_len = strlen(abbrev);
 108
 109         /* Find beginning and end of commit subject. */
 110         p = out->message;
 111         while (*p && (*p != '\n' || p[1] != '\n'))
 112                 p++;
 113         if (*p) {
 114                 p += 2;
 115                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
 116                         ; /* do nothing */
 117         } else
 118                 eol = p;
 119         oneline_len = eol - p;
 120
 121         out->parent_label = xmalloc(strlen("parent of ") + abbrev_len +
 122                               strlen("... ") + oneline_len + 1);
 123         q = out->parent_label;
 124         q = mempcpy(q, "parent of ", strlen("parent of "));
 125         out->label = q;
 126         q = mempcpy(q, abbrev, abbrev_len);
 127         q = mempcpy(q, "... ", strlen("... "));
 128         out->subject = q;
 129         q = mempcpy(q, p, oneline_len);
 130         *q = '\0';
 131         return 0;
 132 }
 133
 134 static void free_message(struct commit_message *msg)
 135 {
 136         free(msg->parent_label);
 137         free(msg->reencoded_message);
 138 }
 139
 140 static char *get_encoding(const char *message)
 141 {
 142         const char *p = message, *eol;
 143
 144         if (!p)
 145                 die ("Could not read commit message of %s",
 146                                 sha1_to_hex(commit->object.sha1));
 147         while (*p && *p != '\n') {
 148                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
 149                         ; /* do nothing */
 150                 if (!prefixcmp(p, "encoding ")) {
 151                         char *result = xmalloc(eol - 8 - p);
 152                         strlcpy(result, p + 9, eol - 8 - p);
 153                         return result;
 154                 }
 155                 p = eol;
 156                 if (*p == '\n')
 157                         p++;
 158         }
 159         return NULL;
 160 }
 161
 162 static void add_message_to_msg(struct strbuf *msgbuf, const char *message)
 163 {
 164         const char *p = message;
 165         while (*p && (*p != '\n' || p[1] != '\n'))
 166                 p++;
 167
 168         if (!*p)
 169                 strbuf_addstr(msgbuf, sha1_to_hex(commit->object.sha1));
 170
 171         p += 2;
 172         strbuf_addstr(msgbuf, p);
 173 }
 174
 175 static void set_author_ident_env(const char *message)
 176 {
 177         const char *p = message;
 178         if (!p)
 179                 die ("Could not read commit message of %s",
 180                                 sha1_to_hex(commit->object.sha1));
 181         while (*p && *p != '\n') {
 182                 const char *eol;
 183
 184                 for (eol = p; *eol && *eol != '\n'; eol++)
 185                         ; /* do nothing */
 186                 if (!prefixcmp(p, "author ")) {
 187                         char *line, *pend, *email, *timestamp;
 188
 189                         p += 7;
 190                         line = xmemdupz(p, eol - p);
 191                         email = strchr(line, '<');
 192                         if (!email)
 193                                 die ("Could not extract author email from %s",
 194                                         sha1_to_hex(commit->object.sha1));
 195                         if (email == line)
 196                                 pend = line;
 197                         else
 198                                 for (pend = email; pend != line + 1 &&
 199                                                 isspace(pend[-1]); pend--);
 200                                         ; /* do nothing */
 201                         *pend = '\0';
 202                         email++;
 203                         timestamp = strchr(email, '>');
 204                         if (!timestamp)
 205                                 die ("Could not extract author time from %s",
 206                                         sha1_to_hex(commit->object.sha1));
 207                         *timestamp = '\0';
 208                         for (timestamp++; *timestamp && isspace(*timestamp);
 209                                         timestamp++)
 210                                 ; /* do nothing */
 211                         setenv("GIT_AUTHOR_NAME", line, 1);
 212                         setenv("GIT_AUTHOR_EMAIL", email, 1);
 213                         setenv("GIT_AUTHOR_DATE", timestamp, 1);
 214                         free(line);
 215                         return;
 216                 }
 217                 p = eol;
 218                 if (*p == '\n')
 219                         p++;
 220         }
 221         die ("No author information found in %s",
 222                         sha1_to_hex(commit->object.sha1));
 223 }
 224
 225 static char *help_msg(const char *name)
 226 {
 227         struct strbuf helpbuf = STRBUF_INIT;
 228         char *msg = getenv("GIT_CHERRY_PICK_HELP");
 229
 230         if (msg)
 231                 return msg;
 232
 233         strbuf_addstr(&helpbuf, "  After resolving the conflicts,\n"
 234                 "mark the corrected paths with 'git add <paths>' or 'git rm <paths>'\n"
 235                 "and commit the result");
 236
 237         if (action == CHERRY_PICK) {
 238                 strbuf_addf(&helpbuf, " with: \n"
 239                         "\n"
 240                         "        git commit -c %s\n",
 241                         name);
 242         }
 243         else
 244                 strbuf_addch(&helpbuf, '.');
 245         return strbuf_detach(&helpbuf, NULL);
 246 }
 247
 248 static void write_message(struct strbuf *msgbuf, const char *filename)
 249 {
 250         static struct lock_file msg_file;
 251
 252         int msg_fd = hold_lock_file_for_update(&msg_file, filename,
 253                                                LOCK_DIE_ON_ERROR);
 254         if (write_in_full(msg_fd, msgbuf->buf, msgbuf->len) < 0)
 255                 die_errno("Could not write to %s.", filename);
 256         strbuf_release(msgbuf);
 257         if (commit_lock_file(&msg_file) < 0)
 258                 die("Error wrapping up %s", filename);
 259 }
 260
 261 static struct tree *empty_tree(void)
 262 {
 263         struct tree *tree = xcalloc(1, sizeof(struct tree));
 264
 265         tree->object.parsed = 1;
 266         tree->object.type = OBJ_TREE;
 267         pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
 268         return tree;
 269 }
 270
 271 static NORETURN void die_dirty_index(const char *me)
 272 {
 273         if (read_cache_unmerged()) {
 274                 die_resolve_conflict(me);
 275         } else {
 276                 if (advice_commit_before_merge)
 277                         die("Your local changes would be overwritten by %s.\n"
 278                             "Please, commit your changes or stash them to proceed.", me);
 279                 else
 280                         die("Your local changes would be overwritten by %s.\n", me);
 281         }
 282 }
 283
 284 static void do_recursive_merge(struct commit *base, struct commit *next,
 285                                const char *base_label, const char *next_label,
 286                                unsigned char *head, struct strbuf *msgbuf,
 287                                char *defmsg)
 288 {
 289         struct merge_options o;
 290         struct tree *result, *next_tree, *base_tree, *head_tree;
 291         int clean, index_fd;
 292         static struct lock_file index_lock;
 293
 294         index_fd = hold_locked_index(&index_lock, 1);
 295
 296         read_cache();
 297         init_merge_options(&o);
 298         o.ancestor = base ? base_label : "(empty tree)";
 299         o.branch1 = "HEAD";
 300         o.branch2 = next ? next_label : "(empty tree)";
 301
 302         head_tree = parse_tree_indirect(head);
 303         next_tree = next ? next->tree : empty_tree();
 304         base_tree = base ? base->tree : empty_tree();
 305
 306         clean = merge_trees(&o,
 307                             head_tree,
 308                             next_tree, base_tree, &result);
 309
 310         if (active_cache_changed &&
 311             (write_cache(index_fd, active_cache, active_nr) ||
 312              commit_locked_index(&index_lock)))
 313                 die("%s: Unable to write new index file", me);
 314         rollback_lock_file(&index_lock);
 315
 316         if (!clean) {
 317                 int i;
 318                 strbuf_addstr(msgbuf, "\nConflicts:\n\n");
 319                 for (i = 0; i < active_nr;) {
 320                         struct cache_entry *ce = active_cache[i++];
 321                         if (ce_stage(ce)) {
 322                                 strbuf_addch(msgbuf, '\t');
 323                                 strbuf_addstr(msgbuf, ce->name);
 324                                 strbuf_addch(msgbuf, '\n');
 325                                 while (i < active_nr && !strcmp(ce->name,
 326                                                 active_cache[i]->name))
 327                                         i++;
 328                         }
 329                 }
 330                 write_message(msgbuf, defmsg);
 331                 fprintf(stderr, "Automatic %s failed.%s\n",
 332                         me, help_msg(commit_name));
 333                 rerere(allow_rerere_auto);
 334                 exit(1);
 335         }
 336         write_message(msgbuf, defmsg);
 337         fprintf(stderr, "Finished one %s.\n", me);
 338 }
 339
 340 static int revert_or_cherry_pick(int argc, const char **argv)
 341 {
 342         unsigned char head[20];
 343         struct commit *base, *next, *parent;
 344         const char *base_label, *next_label;
 345         struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
 346         char *defmsg = git_pathdup("MERGE_MSG");
 347         struct strbuf msgbuf = STRBUF_INIT;
 348
 349         git_config(git_default_config, NULL);
 350         me = action == REVERT ? "revert" : "cherry-pick";
 351         setenv(GIT_REFLOG_ACTION, me, 0);
 352         parse_args(argc, argv);
 353
 354         /* this is copied from the shell script, but it's never triggered... */
 355         if (action == REVERT && !no_replay)
 356                 die("revert is incompatible with replay");
 357
 358         if (read_cache() < 0)
 359                 die("git %s: failed to read the index", me);
 360         if (no_commit) {
 361                 /*
 362                  * We do not intend to commit immediately.  We just want to
 363                  * merge the differences in, so let's compute the tree
 364                  * that represents the "current" state for merge-recursive
 365                  * to work on.
 366                  */
 367                 if (write_cache_as_tree(head, 0, NULL))
 368                         die ("Your index file is unmerged.");
 369         } else {
 370                 if (get_sha1("HEAD", head))
 371                         die ("You do not have a valid HEAD");
 372                 if (index_differs_from("HEAD", 0))
 373                         die_dirty_index(me);
 374         }
 375         discard_cache();
 376
 377         if (!commit->parents) {
 378                 if (action == REVERT)
 379                         die ("Cannot revert a root commit");
 380                 parent = NULL;
 381         }
 382         else if (commit->parents->next) {
 383                 /* Reverting or cherry-picking a merge commit */
 384                 int cnt;
 385                 struct commit_list *p;
 386
 387                 if (!mainline)
 388                         die("Commit %s is a merge but no -m option was given.",
 389                             sha1_to_hex(commit->object.sha1));
 390
 391                 for (cnt = 1, p = commit->parents;
 392                      cnt != mainline && p;
 393                      cnt++)
 394                         p = p->next;
 395                 if (cnt != mainline || !p)
 396                         die("Commit %s does not have parent %d",
 397                             sha1_to_hex(commit->object.sha1), mainline);
 398                 parent = p->item;
 399         } else if (0 < mainline)
 400                 die("Mainline was specified but commit %s is not a merge.",
 401                     sha1_to_hex(commit->object.sha1));
 402         else
 403                 parent = commit->parents->item;
 404
 405         if (parent && parse_commit(parent) < 0)
 406                 die("%s: cannot parse parent commit %s",
 407                     me, sha1_to_hex(parent->object.sha1));
 408
 409         if (get_message(commit->buffer, &msg) != 0)
 410                 die("Cannot get commit message for %s",
 411                                 sha1_to_hex(commit->object.sha1));
 412
 413         /*
 414          * "commit" is an existing commit.  We would want to apply
 415          * the difference it introduces since its first parent "prev"
 416          * on top of the current HEAD if we are cherry-pick.  Or the
 417          * reverse of it if we are revert.
 418          */
 419
 420         if (action == REVERT) {
 421                 base = commit;
 422                 base_label = msg.label;
 423                 next = parent;
 424                 next_label = msg.parent_label;
 425                 strbuf_addstr(&msgbuf, "Revert \"");
 426                 strbuf_addstr(&msgbuf, msg.subject);
 427                 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
 428                 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 429
 430                 if (commit->parents->next) {
 431                         strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
 432                         strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
 433                 }
 434                 strbuf_addstr(&msgbuf, ".\n");
 435         } else {
 436                 base = parent;
 437                 base_label = msg.parent_label;
 438                 next = commit;
 439                 next_label = msg.label;
 440                 set_author_ident_env(msg.message);
 441                 add_message_to_msg(&msgbuf, msg.message);
 442                 if (no_replay) {
 443                         strbuf_addstr(&msgbuf, "(cherry picked from commit ");
 444                         strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 445                         strbuf_addstr(&msgbuf, ")\n");
 446                 }
 447         }
 448
 449         if (!strategy || !strcmp(strategy, "recursive") || action == REVERT)
 450                 do_recursive_merge(base, next, base_label, next_label,
 451                                    head, &msgbuf, defmsg);
 452         else {
 453                 int res;
 454                 struct commit_list *common = NULL;
 455                 struct commit_list *remotes = NULL;
 456                 write_message(&msgbuf, defmsg);
 457                 commit_list_insert(base, &common);
 458                 commit_list_insert(next, &remotes);
 459                 res = try_merge_command(strategy, common,
 460                                         sha1_to_hex(head), remotes);
 461                 free_commit_list(common);
 462                 free_commit_list(remotes);
 463                 if (res) {
 464                         fprintf(stderr, "Automatic %s with strategy %s failed.%s\n",
 465                                 me, strategy, help_msg(commit_name));
 466                         rerere(allow_rerere_auto);
 467                         exit(1);
 468                 }
 469         }
 470
 471         /*
 472          *
 473          * If we are cherry-pick, and if the merge did not result in
 474          * hand-editing, we will hit this commit and inherit the original
 475          * author date and name.
 476          * If we are revert, or if our cherry-pick results in a hand merge,
 477          * we had better say that the current user is responsible for that.
 478          */
 479
 480         if (!no_commit) {
 481                 /* 6 is max possible length of our args array including NULL */
 482                 const char *args[6];
 483                 int i = 0;
 484                 args[i++] = "commit";
 485                 args[i++] = "-n";
 486                 if (signoff)
 487                         args[i++] = "-s";
 488                 if (!edit) {
 489                         args[i++] = "-F";
 490                         args[i++] = defmsg;
 491                 }
 492                 args[i] = NULL;
 493                 return execv_git_cmd(args);
 494         }
 495         free_message(&msg);
 496         free(defmsg);
 497
 498         return 0;
 499 }
 500
 501 int cmd_revert(int argc, const char **argv, const char *prefix)
 502 {
 503         if (isatty(0))
 504                 edit = 1;
 505         no_replay = 1;
 506         action = REVERT;
 507         return revert_or_cherry_pick(argc, argv);
 508 }
 509
 510 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
 511 {
 512         no_replay = 0;
 513         action = CHERRY_PICK;
 514         return revert_or_cherry_pick(argc, argv);
 515 }