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
  15 /*
  16  * This implements the builtins revert and cherry-pick.
  17  *
  18  * Copyright (c) 2007 Johannes E. Schindelin
  19  *
  20  * Based on git-revert.sh, which is
  21  *
  22  * Copyright (c) 2005 Linus Torvalds
  23  * Copyright (c) 2005 Junio C Hamano
  24  */
  25
  26 static const char * const revert_usage[] = {
  27         "git revert [options] <commit-ish>",
  28         NULL
  29 };
  30
  31 static const char * const cherry_pick_usage[] = {
  32         "git cherry-pick [options] <commit-ish>",
  33         NULL
  34 };
  35
  36 static int edit, no_replay, no_commit, mainline, signoff;
  37 static enum { REVERT, CHERRY_PICK } action;
  38 static struct commit *commit;
  39
  40 static const char *me;
  41
  42 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
  43
  44 static void parse_args(int argc, const char **argv)
  45 {
  46         const char * const * usage_str =
  47                 action == REVERT ?  revert_usage : cherry_pick_usage;
  48         unsigned char sha1[20];
  49         const char *arg;
  50         int noop;
  51         struct option options[] = {
  52                 OPT_BOOLEAN('n', "no-commit", &no_commit, "don't automatically commit"),
  53                 OPT_BOOLEAN('e', "edit", &edit, "edit the commit message"),
  54                 OPT_BOOLEAN('x', NULL, &no_replay, "append commit name when cherry-picking"),
  55                 OPT_BOOLEAN('r', NULL, &noop, "no-op (backward compatibility)"),
  56                 OPT_BOOLEAN('s', "signoff", &signoff, "add Signed-off-by:"),
  57                 OPT_INTEGER('m', "mainline", &mainline, "parent number"),
  58                 OPT_END(),
  59         };
  60
  61         if (parse_options(argc, argv, options, usage_str, 0) != 1)
  62                 usage_with_options(usage_str, options);
  63         arg = argv[0];
  64
  65         if (get_sha1(arg, sha1))
  66                 die ("Cannot find '%s'", arg);
  67         commit = (struct commit *)parse_object(sha1);
  68         if (!commit)
  69                 die ("Could not find %s", sha1_to_hex(sha1));
  70         if (commit->object.type == OBJ_TAG) {
  71                 commit = (struct commit *)
  72                         deref_tag((struct object *)commit, arg, strlen(arg));
  73         }
  74         if (commit->object.type != OBJ_COMMIT)
  75                 die ("'%s' does not point to a commit", arg);
  76 }
  77
  78 static char *get_oneline(const char *message)
  79 {
  80         char *result;
  81         const char *p = message, *abbrev, *eol;
  82         int abbrev_len, oneline_len;
  83
  84         if (!p)
  85                 die ("Could not read commit message of %s",
  86                                 sha1_to_hex(commit->object.sha1));
  87         while (*p && (*p != '\n' || p[1] != '\n'))
  88                 p++;
  89
  90         if (*p) {
  91                 p += 2;
  92                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
  93                         ; /* do nothing */
  94         } else
  95                 eol = p;
  96         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
  97         abbrev_len = strlen(abbrev);
  98         oneline_len = eol - p;
  99         result = xmalloc(abbrev_len + 5 + oneline_len);
 100         memcpy(result, abbrev, abbrev_len);
 101         memcpy(result + abbrev_len, "... ", 4);
 102         memcpy(result + abbrev_len + 4, p, oneline_len);
 103         result[abbrev_len + 4 + oneline_len] = '\0';
 104         return result;
 105 }
 106
 107 static char *get_encoding(const char *message)
 108 {
 109         const char *p = message, *eol;
 110
 111         if (!p)
 112                 die ("Could not read commit message of %s",
 113                                 sha1_to_hex(commit->object.sha1));
 114         while (*p && *p != '\n') {
 115                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
 116                         ; /* do nothing */
 117                 if (!prefixcmp(p, "encoding ")) {
 118                         char *result = xmalloc(eol - 8 - p);
 119                         strlcpy(result, p + 9, eol - 8 - p);
 120                         return result;
 121                 }
 122                 p = eol;
 123                 if (*p == '\n')
 124                         p++;
 125         }
 126         return NULL;
 127 }
 128
 129 static struct lock_file msg_file;
 130 static int msg_fd;
 131
 132 static void add_to_msg(const char *string)
 133 {
 134         int len = strlen(string);
 135         if (write_in_full(msg_fd, string, len) < 0)
 136                 die ("Could not write to MERGE_MSG");
 137 }
 138
 139 static void add_message_to_msg(const char *message)
 140 {
 141         const char *p = message;
 142         while (*p && (*p != '\n' || p[1] != '\n'))
 143                 p++;
 144
 145         if (!*p)
 146                 add_to_msg(sha1_to_hex(commit->object.sha1));
 147
 148         p += 2;
 149         add_to_msg(p);
 150         return;
 151 }
 152
 153 static void set_author_ident_env(const char *message)
 154 {
 155         const char *p = message;
 156         if (!p)
 157                 die ("Could not read commit message of %s",
 158                                 sha1_to_hex(commit->object.sha1));
 159         while (*p && *p != '\n') {
 160                 const char *eol;
 161
 162                 for (eol = p; *eol && *eol != '\n'; eol++)
 163                         ; /* do nothing */
 164                 if (!prefixcmp(p, "author ")) {
 165                         char *line, *pend, *email, *timestamp;
 166
 167                         p += 7;
 168                         line = xmemdupz(p, eol - p);
 169                         email = strchr(line, '<');
 170                         if (!email)
 171                                 die ("Could not extract author email from %s",
 172                                         sha1_to_hex(commit->object.sha1));
 173                         if (email == line)
 174                                 pend = line;
 175                         else
 176                                 for (pend = email; pend != line + 1 &&
 177                                                 isspace(pend[-1]); pend--);
 178                                         ; /* do nothing */
 179                         *pend = '\0';
 180                         email++;
 181                         timestamp = strchr(email, '>');
 182                         if (!timestamp)
 183                                 die ("Could not extract author time from %s",
 184                                         sha1_to_hex(commit->object.sha1));
 185                         *timestamp = '\0';
 186                         for (timestamp++; *timestamp && isspace(*timestamp);
 187                                         timestamp++)
 188                                 ; /* do nothing */
 189                         setenv("GIT_AUTHOR_NAME", line, 1);
 190                         setenv("GIT_AUTHOR_EMAIL", email, 1);
 191                         setenv("GIT_AUTHOR_DATE", timestamp, 1);
 192                         free(line);
 193                         return;
 194                 }
 195                 p = eol;
 196                 if (*p == '\n')
 197                         p++;
 198         }
 199         die ("No author information found in %s",
 200                         sha1_to_hex(commit->object.sha1));
 201 }
 202
 203 static int merge_recursive(const char *base_sha1,
 204                 const char *head_sha1, const char *head_name,
 205                 const char *next_sha1, const char *next_name)
 206 {
 207         char buffer[256];
 208         const char *argv[6];
 209         int i = 0;
 210
 211         sprintf(buffer, "GITHEAD_%s", head_sha1);
 212         setenv(buffer, head_name, 1);
 213         sprintf(buffer, "GITHEAD_%s", next_sha1);
 214         setenv(buffer, next_name, 1);
 215
 216         /*
 217          * This three way merge is an interesting one.  We are at
 218          * $head, and would want to apply the change between $commit
 219          * and $prev on top of us (when reverting), or the change between
 220          * $prev and $commit on top of us (when cherry-picking or replaying).
 221          */
 222         argv[i++] = "merge-recursive";
 223         if (base_sha1)
 224                 argv[i++] = base_sha1;
 225         argv[i++] = "--";
 226         argv[i++] = head_sha1;
 227         argv[i++] = next_sha1;
 228         argv[i++] = NULL;
 229
 230         return run_command_v_opt(argv, RUN_COMMAND_NO_STDIN | RUN_GIT_CMD);
 231 }
 232
 233 static char *help_msg(const unsigned char *sha1)
 234 {
 235         static char helpbuf[1024];
 236         char *msg = getenv("GIT_CHERRY_PICK_HELP");
 237
 238         if (msg)
 239                 return msg;
 240
 241         strcpy(helpbuf, "  After resolving the conflicts,\n"
 242                "mark the corrected paths with 'git add <paths>' "
 243                "or 'git rm <paths>' and commit the result.");
 244
 245         if (action == CHERRY_PICK) {
 246                 sprintf(helpbuf + strlen(helpbuf),
 247                         "\nWhen commiting, use the option "
 248                         "'-c %s' to retain authorship and message.",
 249                         find_unique_abbrev(sha1, DEFAULT_ABBREV));
 250         }
 251         return helpbuf;
 252 }
 253
 254 static int index_is_dirty(void)
 255 {
 256         struct rev_info rev;
 257         init_revisions(&rev, NULL);
 258         setup_revisions(0, NULL, &rev, "HEAD");
 259         DIFF_OPT_SET(&rev.diffopt, QUIET);
 260         DIFF_OPT_SET(&rev.diffopt, EXIT_WITH_STATUS);
 261         run_diff_index(&rev, 1);
 262         return !!DIFF_OPT_TST(&rev.diffopt, HAS_CHANGES);
 263 }
 264
 265 static int revert_or_cherry_pick(int argc, const char **argv)
 266 {
 267         unsigned char head[20];
 268         struct commit *base, *next, *parent;
 269         int i;
 270         char *oneline, *reencoded_message = NULL;
 271         const char *message, *encoding;
 272         const char *defmsg = git_pathdup("MERGE_MSG");
 273
 274         git_config(git_default_config, NULL);
 275         me = action == REVERT ? "revert" : "cherry-pick";
 276         setenv(GIT_REFLOG_ACTION, me, 0);
 277         parse_args(argc, argv);
 278
 279         /* this is copied from the shell script, but it's never triggered... */
 280         if (action == REVERT && !no_replay)
 281                 die("revert is incompatible with replay");
 282
 283         if (no_commit) {
 284                 /*
 285                  * We do not intend to commit immediately.  We just want to
 286                  * merge the differences in, so let's compute the tree
 287                  * that represents the "current" state for merge-recursive
 288                  * to work on.
 289                  */
 290                 if (write_cache_as_tree(head, 0, NULL))
 291                         die ("Your index file is unmerged.");
 292         } else {
 293                 if (get_sha1("HEAD", head))
 294                         die ("You do not have a valid HEAD");
 295                 if (read_cache() < 0)
 296                         die("could not read the index");
 297                 if (index_is_dirty())
 298                         die ("Dirty index: cannot %s", me);
 299                 discard_cache();
 300         }
 301
 302         if (!commit->parents) {
 303                 if (action == REVERT)
 304                         die ("Cannot revert a root commit");
 305                 parent = NULL;
 306         }
 307         else if (commit->parents->next) {
 308                 /* Reverting or cherry-picking a merge commit */
 309                 int cnt;
 310                 struct commit_list *p;
 311
 312                 if (!mainline)
 313                         die("Commit %s is a merge but no -m option was given.",
 314                             sha1_to_hex(commit->object.sha1));
 315
 316                 for (cnt = 1, p = commit->parents;
 317                      cnt != mainline && p;
 318                      cnt++)
 319                         p = p->next;
 320                 if (cnt != mainline || !p)
 321                         die("Commit %s does not have parent %d",
 322                             sha1_to_hex(commit->object.sha1), mainline);
 323                 parent = p->item;
 324         } else if (0 < mainline)
 325                 die("Mainline was specified but commit %s is not a merge.",
 326                     sha1_to_hex(commit->object.sha1));
 327         else
 328                 parent = commit->parents->item;
 329
 330         if (!(message = commit->buffer))
 331                 die ("Cannot get commit message for %s",
 332                                 sha1_to_hex(commit->object.sha1));
 333
 334         /*
 335          * "commit" is an existing commit.  We would want to apply
 336          * the difference it introduces since its first parent "prev"
 337          * on top of the current HEAD if we are cherry-pick.  Or the
 338          * reverse of it if we are revert.
 339          */
 340
 341         msg_fd = hold_lock_file_for_update(&msg_file, defmsg, 1);
 342
 343         encoding = get_encoding(message);
 344         if (!encoding)
 345                 encoding = "utf-8";
 346         if (!git_commit_encoding)
 347                 git_commit_encoding = "utf-8";
 348         if ((reencoded_message = reencode_string(message,
 349                                         git_commit_encoding, encoding)))
 350                 message = reencoded_message;
 351
 352         oneline = get_oneline(message);
 353
 354         if (action == REVERT) {
 355                 char *oneline_body = strchr(oneline, ' ');
 356
 357                 base = commit;
 358                 next = parent;
 359                 add_to_msg("Revert \"");
 360                 add_to_msg(oneline_body + 1);
 361                 add_to_msg("\"\n\nThis reverts commit ");
 362                 add_to_msg(sha1_to_hex(commit->object.sha1));
 363                 add_to_msg(".\n");
 364         } else {
 365                 base = parent;
 366                 next = commit;
 367                 set_author_ident_env(message);
 368                 add_message_to_msg(message);
 369                 if (no_replay) {
 370                         add_to_msg("(cherry picked from commit ");
 371                         add_to_msg(sha1_to_hex(commit->object.sha1));
 372                         add_to_msg(")\n");
 373                 }
 374         }
 375
 376         if (merge_recursive(base == NULL ?
 377                                 NULL : sha1_to_hex(base->object.sha1),
 378                                 sha1_to_hex(head), "HEAD",
 379                                 sha1_to_hex(next->object.sha1), oneline) ||
 380                         write_cache_as_tree(head, 0, NULL)) {
 381                 add_to_msg("\nConflicts:\n\n");
 382                 read_cache();
 383                 for (i = 0; i < active_nr;) {
 384                         struct cache_entry *ce = active_cache[i++];
 385                         if (ce_stage(ce)) {
 386                                 add_to_msg("\t");
 387                                 add_to_msg(ce->name);
 388                                 add_to_msg("\n");
 389                                 while (i < active_nr && !strcmp(ce->name,
 390                                                 active_cache[i]->name))
 391                                         i++;
 392                         }
 393                 }
 394                 if (commit_lock_file(&msg_file) < 0)
 395                         die ("Error wrapping up %s", defmsg);
 396                 fprintf(stderr, "Automatic %s failed.%s\n",
 397                         me, help_msg(commit->object.sha1));
 398                 exit(1);
 399         }
 400         if (commit_lock_file(&msg_file) < 0)
 401                 die ("Error wrapping up %s", defmsg);
 402         fprintf(stderr, "Finished one %s.\n", me);
 403
 404         /*
 405          *
 406          * If we are cherry-pick, and if the merge did not result in
 407          * hand-editing, we will hit this commit and inherit the original
 408          * author date and name.
 409          * If we are revert, or if our cherry-pick results in a hand merge,
 410          * we had better say that the current user is responsible for that.
 411          */
 412
 413         if (!no_commit) {
 414                 /* 6 is max possible length of our args array including NULL */
 415                 const char *args[6];
 416                 int i = 0;
 417                 args[i++] = "commit";
 418                 args[i++] = "-n";
 419                 if (signoff)
 420                         args[i++] = "-s";
 421                 if (!edit) {
 422                         args[i++] = "-F";
 423                         args[i++] = defmsg;
 424                 }
 425                 args[i] = NULL;
 426                 return execv_git_cmd(args);
 427         }
 428         free(reencoded_message);
 429
 430         return 0;
 431 }
 432
 433 int cmd_revert(int argc, const char **argv, const char *prefix)
 434 {
 435         if (isatty(0))
 436                 edit = 1;
 437         no_replay = 1;
 438         action = REVERT;
 439         return revert_or_cherry_pick(argc, argv);
 440 }
 441
 442 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
 443 {
 444         no_replay = 0;
 445         action = CHERRY_PICK;
 446         return revert_or_cherry_pick(argc, argv);
 447 }