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 = 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 unsigned char *sha1)
 202 {
 203         static char helpbuf[1024];
 204         char *msg = getenv("GIT_CHERRY_PICK_HELP");
 205
 206         if (msg)
 207                 return msg;
 208
 209         strcpy(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                 sprintf(helpbuf + strlen(helpbuf),
 215                         "  When committing, use the option '-c %s'\n"
 216                         "to retain authorship and message.",
 217                         find_unique_abbrev(sha1, DEFAULT_ABBREV));
 218         }
 219         return helpbuf;
 220 }
 221
 222 static struct tree *empty_tree(void)
 223 {
 224         struct tree *tree = xcalloc(1, sizeof(struct tree));
 225
 226         tree->object.parsed = 1;
 227         tree->object.type = OBJ_TREE;
 228         pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
 229         return tree;
 230 }
 231
 232 static NORETURN void die_dirty_index(const char *me)
 233 {
 234         if (read_cache_unmerged()) {
 235                 die_resolve_conflict(me);
 236         } else {
 237                 if (advice_commit_before_merge)
 238                         die("Your local changes would be overwritten by %s.\n"
 239                             "Please, commit your changes or stash them to proceed.", me);
 240                 else
 241                         die("Your local changes would be overwritten by %s.\n", me);
 242         }
 243 }
 244
 245 static int revert_or_cherry_pick(int argc, const char **argv)
 246 {
 247         unsigned char head[20];
 248         struct commit *base, *next, *parent;
 249         int i, index_fd, clean;
 250         char *oneline, *reencoded_message = NULL;
 251         const char *message, *encoding;
 252         char *defmsg = git_pathdup("MERGE_MSG");
 253         struct merge_options o;
 254         struct tree *result, *next_tree, *base_tree, *head_tree;
 255         static struct lock_file index_lock;
 256
 257         git_config(git_default_config, NULL);
 258         me = action == REVERT ? "revert" : "cherry-pick";
 259         setenv(GIT_REFLOG_ACTION, me, 0);
 260         parse_args(argc, argv);
 261
 262         /* this is copied from the shell script, but it's never triggered... */
 263         if (action == REVERT && !no_replay)
 264                 die("revert is incompatible with replay");
 265
 266         if (read_cache() < 0)
 267                 die("git %s: failed to read the index", me);
 268         if (no_commit) {
 269                 /*
 270                  * We do not intend to commit immediately.  We just want to
 271                  * merge the differences in, so let's compute the tree
 272                  * that represents the "current" state for merge-recursive
 273                  * to work on.
 274                  */
 275                 if (write_cache_as_tree(head, 0, NULL))
 276                         die ("Your index file is unmerged.");
 277         } else {
 278                 if (get_sha1("HEAD", head))
 279                         die ("You do not have a valid HEAD");
 280                 if (index_differs_from("HEAD", 0))
 281                         die_dirty_index(me);
 282         }
 283         discard_cache();
 284
 285         index_fd = hold_locked_index(&index_lock, 1);
 286
 287         if (!commit->parents) {
 288                 if (action == REVERT)
 289                         die ("Cannot revert a root commit");
 290                 parent = NULL;
 291         }
 292         else if (commit->parents->next) {
 293                 /* Reverting or cherry-picking a merge commit */
 294                 int cnt;
 295                 struct commit_list *p;
 296
 297                 if (!mainline)
 298                         die("Commit %s is a merge but no -m option was given.",
 299                             sha1_to_hex(commit->object.sha1));
 300
 301                 for (cnt = 1, p = commit->parents;
 302                      cnt != mainline && p;
 303                      cnt++)
 304                         p = p->next;
 305                 if (cnt != mainline || !p)
 306                         die("Commit %s does not have parent %d",
 307                             sha1_to_hex(commit->object.sha1), mainline);
 308                 parent = p->item;
 309         } else if (0 < mainline)
 310                 die("Mainline was specified but commit %s is not a merge.",
 311                     sha1_to_hex(commit->object.sha1));
 312         else
 313                 parent = commit->parents->item;
 314
 315         if (!(message = commit->buffer))
 316                 die ("Cannot get commit message for %s",
 317                                 sha1_to_hex(commit->object.sha1));
 318
 319         if (parent && parse_commit(parent) < 0)
 320                 die("%s: cannot parse parent commit %s",
 321                     me, sha1_to_hex(parent->object.sha1));
 322
 323         /*
 324          * "commit" is an existing commit.  We would want to apply
 325          * the difference it introduces since its first parent "prev"
 326          * on top of the current HEAD if we are cherry-pick.  Or the
 327          * reverse of it if we are revert.
 328          */
 329
 330         msg_fd = hold_lock_file_for_update(&msg_file, defmsg,
 331                                            LOCK_DIE_ON_ERROR);
 332
 333         encoding = get_encoding(message);
 334         if (!encoding)
 335                 encoding = "UTF-8";
 336         if (!git_commit_encoding)
 337                 git_commit_encoding = "UTF-8";
 338         if ((reencoded_message = reencode_string(message,
 339                                         git_commit_encoding, encoding)))
 340                 message = reencoded_message;
 341
 342         oneline = get_oneline(message);
 343
 344         if (action == REVERT) {
 345                 char *oneline_body = strchr(oneline, ' ');
 346
 347                 base = commit;
 348                 next = parent;
 349                 add_to_msg("Revert \"");
 350                 add_to_msg(oneline_body + 1);
 351                 add_to_msg("\"\n\nThis reverts commit ");
 352                 add_to_msg(sha1_to_hex(commit->object.sha1));
 353
 354                 if (commit->parents->next) {
 355                         add_to_msg(", reversing\nchanges made to ");
 356                         add_to_msg(sha1_to_hex(parent->object.sha1));
 357                 }
 358                 add_to_msg(".\n");
 359         } else {
 360                 base = parent;
 361                 next = commit;
 362                 set_author_ident_env(message);
 363                 add_message_to_msg(message);
 364                 if (no_replay) {
 365                         add_to_msg("(cherry picked from commit ");
 366                         add_to_msg(sha1_to_hex(commit->object.sha1));
 367                         add_to_msg(")\n");
 368                 }
 369         }
 370
 371         read_cache();
 372         init_merge_options(&o);
 373         o.branch1 = "HEAD";
 374         o.branch2 = oneline;
 375
 376         head_tree = parse_tree_indirect(head);
 377         next_tree = next ? next->tree : empty_tree();
 378         base_tree = base ? base->tree : empty_tree();
 379
 380         clean = merge_trees(&o,
 381                             head_tree,
 382                             next_tree, base_tree, &result);
 383
 384         if (active_cache_changed &&
 385             (write_cache(index_fd, active_cache, active_nr) ||
 386              commit_locked_index(&index_lock)))
 387                 die("%s: Unable to write new index file", me);
 388         rollback_lock_file(&index_lock);
 389
 390         if (!clean) {
 391                 add_to_msg("\nConflicts:\n\n");
 392                 for (i = 0; i < active_nr;) {
 393                         struct cache_entry *ce = active_cache[i++];
 394                         if (ce_stage(ce)) {
 395                                 add_to_msg("\t");
 396                                 add_to_msg(ce->name);
 397                                 add_to_msg("\n");
 398                                 while (i < active_nr && !strcmp(ce->name,
 399                                                 active_cache[i]->name))
 400                                         i++;
 401                         }
 402                 }
 403                 if (commit_lock_file(&msg_file) < 0)
 404                         die ("Error wrapping up %s", defmsg);
 405                 fprintf(stderr, "Automatic %s failed.%s\n",
 406                         me, help_msg(commit->object.sha1));
 407                 rerere(allow_rerere_auto);
 408                 exit(1);
 409         }
 410         if (commit_lock_file(&msg_file) < 0)
 411                 die ("Error wrapping up %s", defmsg);
 412         fprintf(stderr, "Finished one %s.\n", me);
 413
 414         /*
 415          *
 416          * If we are cherry-pick, and if the merge did not result in
 417          * hand-editing, we will hit this commit and inherit the original
 418          * author date and name.
 419          * If we are revert, or if our cherry-pick results in a hand merge,
 420          * we had better say that the current user is responsible for that.
 421          */
 422
 423         if (!no_commit) {
 424                 /* 6 is max possible length of our args array including NULL */
 425                 const char *args[6];
 426                 int i = 0;
 427                 args[i++] = "commit";
 428                 args[i++] = "-n";
 429                 if (signoff)
 430                         args[i++] = "-s";
 431                 if (!edit) {
 432                         args[i++] = "-F";
 433                         args[i++] = defmsg;
 434                 }
 435                 args[i] = NULL;
 436                 return execv_git_cmd(args);
 437         }
 438         free(reencoded_message);
 439         free(defmsg);
 440
 441         return 0;
 442 }
 443
 444 int cmd_revert(int argc, const char **argv, const char *prefix)
 445 {
 446         if (isatty(0))
 447                 edit = 1;
 448         no_replay = 1;
 449         action = REVERT;
 450         return revert_or_cherry_pick(argc, argv);
 451 }
 452
 453 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
 454 {
 455         no_replay = 0;
 456         action = CHERRY_PICK;
 457         return revert_or_cherry_pick(argc, argv);
 458 }