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
  16 /*
  17  * This implements the builtins revert and cherry-pick.
  18  *
  19  * Copyright (c) 2007 Johannes E. Schindelin
  20  *
  21  * Based on git-revert.sh, which is
  22  *
  23  * Copyright (c) 2005 Linus Torvalds
  24  * Copyright (c) 2005 Junio C Hamano
  25  */
  26
  27 static const char * const revert_usage[] = {
  28         "git revert [options] <commit-ish>",
  29         NULL
  30 };
  31
  32 static const char * const cherry_pick_usage[] = {
  33         "git cherry-pick [options] <commit-ish>",
  34         NULL
  35 };
  36
  37 static int edit, no_replay, no_commit, mainline, signoff;
  38 static enum { REVERT, CHERRY_PICK } action;
  39 static struct commit *commit;
  40
  41 static const char *me;
  42
  43 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
  44
  45 static void parse_args(int argc, const char **argv)
  46 {
  47         const char * const * usage_str =
  48                 action == REVERT ?  revert_usage : cherry_pick_usage;
  49         unsigned char sha1[20];
  50         const char *arg;
  51         int noop;
  52         struct option options[] = {
  53                 OPT_BOOLEAN('n', "no-commit", &no_commit, "don't automatically commit"),
  54                 OPT_BOOLEAN('e', "edit", &edit, "edit the commit message"),
  55                 OPT_BOOLEAN('x', NULL, &no_replay, "append commit name when cherry-picking"),
  56                 OPT_BOOLEAN('r', NULL, &noop, "no-op (backward compatibility)"),
  57                 OPT_BOOLEAN('s', "signoff", &signoff, "add Signed-off-by:"),
  58                 OPT_INTEGER('m', "mainline", &mainline, "parent number"),
  59                 OPT_END(),
  60         };
  61
  62         if (parse_options(argc, argv, options, usage_str, 0) != 1)
  63                 usage_with_options(usage_str, options);
  64         arg = argv[0];
  65
  66         if (get_sha1(arg, sha1))
  67                 die ("Cannot find '%s'", arg);
  68         commit = (struct commit *)parse_object(sha1);
  69         if (!commit)
  70                 die ("Could not find %s", sha1_to_hex(sha1));
  71         if (commit->object.type == OBJ_TAG) {
  72                 commit = (struct commit *)
  73                         deref_tag((struct object *)commit, arg, strlen(arg));
  74         }
  75         if (commit->object.type != OBJ_COMMIT)
  76                 die ("'%s' does not point to a commit", arg);
  77 }
  78
  79 static char *get_oneline(const char *message)
  80 {
  81         char *result;
  82         const char *p = message, *abbrev, *eol;
  83         int abbrev_len, oneline_len;
  84
  85         if (!p)
  86                 die ("Could not read commit message of %s",
  87                                 sha1_to_hex(commit->object.sha1));
  88         while (*p && (*p != '\n' || p[1] != '\n'))
  89                 p++;
  90
  91         if (*p) {
  92                 p += 2;
  93                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
  94                         ; /* do nothing */
  95         } else
  96                 eol = p;
  97         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
  98         abbrev_len = strlen(abbrev);
  99         oneline_len = eol - p;
 100         result = xmalloc(abbrev_len + 5 + oneline_len);
 101         memcpy(result, abbrev, abbrev_len);
 102         memcpy(result + abbrev_len, "... ", 4);
 103         memcpy(result + abbrev_len + 4, p, oneline_len);
 104         result[abbrev_len + 4 + oneline_len] = '\0';
 105         return result;
 106 }
 107
 108 static char *get_encoding(const char *message)
 109 {
 110         const char *p = message, *eol;
 111
 112         if (!p)
 113                 die ("Could not read commit message of %s",
 114                                 sha1_to_hex(commit->object.sha1));
 115         while (*p && *p != '\n') {
 116                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
 117                         ; /* do nothing */
 118                 if (!prefixcmp(p, "encoding ")) {
 119                         char *result = xmalloc(eol - 8 - p);
 120                         strlcpy(result, p + 9, eol - 8 - p);
 121                         return result;
 122                 }
 123                 p = eol;
 124                 if (*p == '\n')
 125                         p++;
 126         }
 127         return NULL;
 128 }
 129
 130 static struct lock_file msg_file;
 131 static int msg_fd;
 132
 133 static void add_to_msg(const char *string)
 134 {
 135         int len = strlen(string);
 136         if (write_in_full(msg_fd, string, len) < 0)
 137                 die ("Could not write to MERGE_MSG");
 138 }
 139
 140 static void add_message_to_msg(const char *message)
 141 {
 142         const char *p = message;
 143         while (*p && (*p != '\n' || p[1] != '\n'))
 144                 p++;
 145
 146         if (!*p)
 147                 add_to_msg(sha1_to_hex(commit->object.sha1));
 148
 149         p += 2;
 150         add_to_msg(p);
 151         return;
 152 }
 153
 154 static void set_author_ident_env(const char *message)
 155 {
 156         const char *p = message;
 157         if (!p)
 158                 die ("Could not read commit message of %s",
 159                                 sha1_to_hex(commit->object.sha1));
 160         while (*p && *p != '\n') {
 161                 const char *eol;
 162
 163                 for (eol = p; *eol && *eol != '\n'; eol++)
 164                         ; /* do nothing */
 165                 if (!prefixcmp(p, "author ")) {
 166                         char *line, *pend, *email, *timestamp;
 167
 168                         p += 7;
 169                         line = xmemdupz(p, eol - p);
 170                         email = strchr(line, '<');
 171                         if (!email)
 172                                 die ("Could not extract author email from %s",
 173                                         sha1_to_hex(commit->object.sha1));
 174                         if (email == line)
 175                                 pend = line;
 176                         else
 177                                 for (pend = email; pend != line + 1 &&
 178                                                 isspace(pend[-1]); pend--);
 179                                         ; /* do nothing */
 180                         *pend = '\0';
 181                         email++;
 182                         timestamp = strchr(email, '>');
 183                         if (!timestamp)
 184                                 die ("Could not extract author time from %s",
 185                                         sha1_to_hex(commit->object.sha1));
 186                         *timestamp = '\0';
 187                         for (timestamp++; *timestamp && isspace(*timestamp);
 188                                         timestamp++)
 189                                 ; /* do nothing */
 190                         setenv("GIT_AUTHOR_NAME", line, 1);
 191                         setenv("GIT_AUTHOR_EMAIL", email, 1);
 192                         setenv("GIT_AUTHOR_DATE", timestamp, 1);
 193                         free(line);
 194                         return;
 195                 }
 196                 p = eol;
 197                 if (*p == '\n')
 198                         p++;
 199         }
 200         die ("No author information found in %s",
 201                         sha1_to_hex(commit->object.sha1));
 202 }
 203
 204 static int merge_recursive(const char *base_sha1,
 205                 const char *head_sha1, const char *head_name,
 206                 const char *next_sha1, const char *next_name)
 207 {
 208         char buffer[256];
 209         const char *argv[6];
 210         int i = 0;
 211
 212         sprintf(buffer, "GITHEAD_%s", head_sha1);
 213         setenv(buffer, head_name, 1);
 214         sprintf(buffer, "GITHEAD_%s", next_sha1);
 215         setenv(buffer, next_name, 1);
 216
 217         /*
 218          * This three way merge is an interesting one.  We are at
 219          * $head, and would want to apply the change between $commit
 220          * and $prev on top of us (when reverting), or the change between
 221          * $prev and $commit on top of us (when cherry-picking or replaying).
 222          */
 223         argv[i++] = "merge-recursive";
 224         if (base_sha1)
 225                 argv[i++] = base_sha1;
 226         argv[i++] = "--";
 227         argv[i++] = head_sha1;
 228         argv[i++] = next_sha1;
 229         argv[i++] = NULL;
 230
 231         return run_command_v_opt(argv, RUN_COMMAND_NO_STDIN | RUN_GIT_CMD);
 232 }
 233
 234 static char *help_msg(const unsigned char *sha1)
 235 {
 236         static char helpbuf[1024];
 237         char *msg = getenv("GIT_CHERRY_PICK_HELP");
 238
 239         if (msg)
 240                 return msg;
 241
 242         strcpy(helpbuf, "  After resolving the conflicts,\n"
 243                "mark the corrected paths with 'git add <paths>' "
 244                "or 'git rm <paths>' and commit the result.");
 245
 246         if (action == CHERRY_PICK) {
 247                 sprintf(helpbuf + strlen(helpbuf),
 248                         "\nWhen commiting, use the option "
 249                         "'-c %s' to retain authorship and message.",
 250                         find_unique_abbrev(sha1, DEFAULT_ABBREV));
 251         }
 252         return helpbuf;
 253 }
 254
 255 static int index_is_dirty(void)
 256 {
 257         struct rev_info rev;
 258         init_revisions(&rev, NULL);
 259         setup_revisions(0, NULL, &rev, "HEAD");
 260         DIFF_OPT_SET(&rev.diffopt, QUIET);
 261         DIFF_OPT_SET(&rev.diffopt, EXIT_WITH_STATUS);
 262         run_diff_index(&rev, 1);
 263         return !!DIFF_OPT_TST(&rev.diffopt, HAS_CHANGES);
 264 }
 265
 266 static int revert_or_cherry_pick(int argc, const char **argv)
 267 {
 268         unsigned char head[20];
 269         struct commit *base, *next, *parent;
 270         int i;
 271         char *oneline, *reencoded_message = NULL;
 272         const char *message, *encoding;
 273         const char *defmsg = xstrdup(git_path("MERGE_MSG"));
 274
 275         git_config(git_default_config, NULL);
 276         me = action == REVERT ? "revert" : "cherry-pick";
 277         setenv(GIT_REFLOG_ACTION, me, 0);
 278         parse_args(argc, argv);
 279
 280         /* this is copied from the shell script, but it's never triggered... */
 281         if (action == REVERT && !no_replay)
 282                 die("revert is incompatible with replay");
 283
 284         if (no_commit) {
 285                 /*
 286                  * We do not intend to commit immediately.  We just want to
 287                  * merge the differences in, so let's compute the tree
 288                  * that represents the "current" state for merge-recursive
 289                  * to work on.
 290                  */
 291                 if (write_cache_as_tree(head, 0, NULL))
 292                         die ("Your index file is unmerged.");
 293         } else {
 294                 if (get_sha1("HEAD", head))
 295                         die ("You do not have a valid HEAD");
 296                 if (read_cache() < 0)
 297                         die("could not read the index");
 298                 if (index_is_dirty())
 299                         die ("Dirty index: cannot %s", me);
 300                 discard_cache();
 301         }
 302
 303         if (!commit->parents) {
 304                 if (action == REVERT)
 305                         die ("Cannot revert a root commit");
 306                 parent = NULL;
 307         }
 308         else if (commit->parents->next) {
 309                 /* Reverting or cherry-picking a merge commit */
 310                 int cnt;
 311                 struct commit_list *p;
 312
 313                 if (!mainline)
 314                         die("Commit %s is a merge but no -m option was given.",
 315                             sha1_to_hex(commit->object.sha1));
 316
 317                 for (cnt = 1, p = commit->parents;
 318                      cnt != mainline && p;
 319                      cnt++)
 320                         p = p->next;
 321                 if (cnt != mainline || !p)
 322                         die("Commit %s does not have parent %d",
 323                             sha1_to_hex(commit->object.sha1), mainline);
 324                 parent = p->item;
 325         } else if (0 < mainline)
 326                 die("Mainline was specified but commit %s is not a merge.",
 327                     sha1_to_hex(commit->object.sha1));
 328         else
 329                 parent = commit->parents->item;
 330
 331         if (!(message = commit->buffer))
 332                 die ("Cannot get commit message for %s",
 333                                 sha1_to_hex(commit->object.sha1));
 334
 335         /*
 336          * "commit" is an existing commit.  We would want to apply
 337          * the difference it introduces since its first parent "prev"
 338          * on top of the current HEAD if we are cherry-pick.  Or the
 339          * reverse of it if we are revert.
 340          */
 341
 342         msg_fd = hold_lock_file_for_update(&msg_file, defmsg, 1);
 343
 344         encoding = get_encoding(message);
 345         if (!encoding)
 346                 encoding = "utf-8";
 347         if (!git_commit_encoding)
 348                 git_commit_encoding = "utf-8";
 349         if ((reencoded_message = reencode_string(message,
 350                                         git_commit_encoding, encoding)))
 351                 message = reencoded_message;
 352
 353         oneline = get_oneline(message);
 354
 355         if (action == REVERT) {
 356                 char *oneline_body = strchr(oneline, ' ');
 357
 358                 base = commit;
 359                 next = parent;
 360                 add_to_msg("Revert \"");
 361                 add_to_msg(oneline_body + 1);
 362                 add_to_msg("\"\n\nThis reverts commit ");
 363                 add_to_msg(sha1_to_hex(commit->object.sha1));
 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         if (merge_recursive(base == NULL ?
 378                                 NULL : sha1_to_hex(base->object.sha1),
 379                                 sha1_to_hex(head), "HEAD",
 380                                 sha1_to_hex(next->object.sha1), oneline) ||
 381                         write_cache_as_tree(head, 0, NULL)) {
 382                 add_to_msg("\nConflicts:\n\n");
 383                 read_cache();
 384                 for (i = 0; i < active_nr;) {
 385                         struct cache_entry *ce = active_cache[i++];
 386                         if (ce_stage(ce)) {
 387                                 add_to_msg("\t");
 388                                 add_to_msg(ce->name);
 389                                 add_to_msg("\n");
 390                                 while (i < active_nr && !strcmp(ce->name,
 391                                                 active_cache[i]->name))
 392                                         i++;
 393                         }
 394                 }
 395                 if (commit_lock_file(&msg_file) < 0)
 396                         die ("Error wrapping up %s", defmsg);
 397                 fprintf(stderr, "Automatic %s failed.%s\n",
 398                         me, help_msg(commit->object.sha1));
 399                 rerere();
 400                 exit(1);
 401         }
 402         if (commit_lock_file(&msg_file) < 0)
 403                 die ("Error wrapping up %s", defmsg);
 404         fprintf(stderr, "Finished one %s.\n", me);
 405
 406         /*
 407          *
 408          * If we are cherry-pick, and if the merge did not result in
 409          * hand-editing, we will hit this commit and inherit the original
 410          * author date and name.
 411          * If we are revert, or if our cherry-pick results in a hand merge,
 412          * we had better say that the current user is responsible for that.
 413          */
 414
 415         if (!no_commit) {
 416                 /* 6 is max possible length of our args array including NULL */
 417                 const char *args[6];
 418                 int i = 0;
 419                 args[i++] = "commit";
 420                 args[i++] = "-n";
 421                 if (signoff)
 422                         args[i++] = "-s";
 423                 if (!edit) {
 424                         args[i++] = "-F";
 425                         args[i++] = defmsg;
 426                 }
 427                 args[i] = NULL;
 428                 return execv_git_cmd(args);
 429         }
 430         free(reencoded_message);
 431
 432         return 0;
 433 }
 434
 435 int cmd_revert(int argc, const char **argv, const char *prefix)
 436 {
 437         if (isatty(0))
 438                 edit = 1;
 439         no_replay = 1;
 440         action = REVERT;
 441         return revert_or_cherry_pick(argc, argv);
 442 }
 443
 444 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
 445 {
 446         no_replay = 0;
 447         action = CHERRY_PICK;
 448         return revert_or_cherry_pick(argc, argv);
 449 }