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