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
  11 /*
  12  * This implements the builtins revert and cherry-pick.
  13  *
  14  * Copyright (c) 2007 Johannes E. Schindelin
  15  *
  16  * Based on git-revert.sh, which is
  17  *
  18  * Copyright (c) 2005 Linus Torvalds
  19  * Copyright (c) 2005 Junio C Hamano
  20  */
  21
  22 static const char *revert_usage = "git-revert [--edit | --no-edit] [-n] [-m parent-number] <commit-ish>";
  23
  24 static const char *cherry_pick_usage = "git-cherry-pick [--edit] [-n] [-m parent-number] [-r] [-x] <commit-ish>";
  25
  26 static int edit;
  27 static int replay;
  28 static enum { REVERT, CHERRY_PICK } action;
  29 static int no_commit;
  30 static struct commit *commit;
  31 static int needed_deref;
  32 static int mainline;
  33
  34 static const char *me;
  35
  36 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
  37
  38 static void parse_options(int argc, const char **argv)
  39 {
  40         const char *usage_str = action == REVERT ?
  41                 revert_usage : cherry_pick_usage;
  42         unsigned char sha1[20];
  43         const char *arg;
  44         int i;
  45
  46         if (argc < 2)
  47                 usage(usage_str);
  48
  49         for (i = 1; i < argc; i++) {
  50                 arg = argv[i];
  51                 if (arg[0] != '-')
  52                         break;
  53                 if (!strcmp(arg, "-n") || !strcmp(arg, "--no-commit"))
  54                         no_commit = 1;
  55                 else if (!strcmp(arg, "-e") || !strcmp(arg, "--edit"))
  56                         edit = 1;
  57                 else if (!strcmp(arg, "--no-edit"))
  58                         edit = 0;
  59                 else if (!strcmp(arg, "-x") || !strcmp(arg, "--i-really-want-"
  60                                 "to-expose-my-private-commit-object-name"))
  61                         replay = 0;
  62                 else if (!strcmp(arg, "-m") || !strcmp(arg, "--mainline")) {
  63                         if (++i >= argc ||
  64                             strtol_i(argv[i], 10, &mainline) ||
  65                             mainline <= 0)
  66                                 usage(usage_str);
  67                 }
  68                 else if (strcmp(arg, "-r"))
  69                         usage(usage_str);
  70         }
  71         if (i != argc - 1)
  72                 usage(usage_str);
  73         arg = argv[argc - 1];
  74         if (get_sha1(arg, sha1))
  75                 die ("Cannot find '%s'", arg);
  76         commit = (struct commit *)parse_object(sha1);
  77         if (!commit)
  78                 die ("Could not find %s", sha1_to_hex(sha1));
  79         if (commit->object.type == OBJ_TAG) {
  80                 commit = (struct commit *)
  81                         deref_tag((struct object *)commit, arg, strlen(arg));
  82                 needed_deref = 1;
  83         }
  84         if (commit->object.type != OBJ_COMMIT)
  85                 die ("'%s' does not point to a commit", arg);
  86 }
  87
  88 static char *get_oneline(const char *message)
  89 {
  90         char *result;
  91         const char *p = message, *abbrev, *eol;
  92         int abbrev_len, oneline_len;
  93
  94         if (!p)
  95                 die ("Could not read commit message of %s",
  96                                 sha1_to_hex(commit->object.sha1));
  97         while (*p && (*p != '\n' || p[1] != '\n'))
  98                 p++;
  99
 100         if (*p) {
 101                 p += 2;
 102                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
 103                         ; /* do nothing */
 104         } else
 105                 eol = p;
 106         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
 107         abbrev_len = strlen(abbrev);
 108         oneline_len = eol - p;
 109         result = xmalloc(abbrev_len + 5 + oneline_len);
 110         memcpy(result, abbrev, abbrev_len);
 111         memcpy(result + abbrev_len, "... ", 4);
 112         memcpy(result + abbrev_len + 4, p, oneline_len);
 113         result[abbrev_len + 4 + oneline_len] = '\0';
 114         return result;
 115 }
 116
 117 static char *get_encoding(const char *message)
 118 {
 119         const char *p = message, *eol;
 120
 121         if (!p)
 122                 die ("Could not read commit message of %s",
 123                                 sha1_to_hex(commit->object.sha1));
 124         while (*p && *p != '\n') {
 125                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
 126                         ; /* do nothing */
 127                 if (!prefixcmp(p, "encoding ")) {
 128                         char *result = xmalloc(eol - 8 - p);
 129                         strlcpy(result, p + 9, eol - 8 - p);
 130                         return result;
 131                 }
 132                 p = eol;
 133                 if (*p == '\n')
 134                         p++;
 135         }
 136         return NULL;
 137 }
 138
 139 static struct lock_file msg_file;
 140 static int msg_fd;
 141
 142 static void add_to_msg(const char *string)
 143 {
 144         int len = strlen(string);
 145         if (write_in_full(msg_fd, string, len) < 0)
 146                 die ("Could not write to MERGE_MSG");
 147 }
 148
 149 static void add_message_to_msg(const char *message)
 150 {
 151         const char *p = message;
 152         while (*p && (*p != '\n' || p[1] != '\n'))
 153                 p++;
 154
 155         if (!*p)
 156                 add_to_msg(sha1_to_hex(commit->object.sha1));
 157
 158         p += 2;
 159         add_to_msg(p);
 160         return;
 161 }
 162
 163 static void set_author_ident_env(const char *message)
 164 {
 165         const char *p = message;
 166         if (!p)
 167                 die ("Could not read commit message of %s",
 168                                 sha1_to_hex(commit->object.sha1));
 169         while (*p && *p != '\n') {
 170                 const char *eol;
 171
 172                 for (eol = p; *eol && *eol != '\n'; eol++)
 173                         ; /* do nothing */
 174                 if (!prefixcmp(p, "author ")) {
 175                         char *line, *pend, *email, *timestamp;
 176
 177                         p += 7;
 178                         line = xmemdupz(p, eol - p);
 179                         email = strchr(line, '<');
 180                         if (!email)
 181                                 die ("Could not extract author email from %s",
 182                                         sha1_to_hex(commit->object.sha1));
 183                         if (email == line)
 184                                 pend = line;
 185                         else
 186                                 for (pend = email; pend != line + 1 &&
 187                                                 isspace(pend[-1]); pend--);
 188                                         ; /* do nothing */
 189                         *pend = '\0';
 190                         email++;
 191                         timestamp = strchr(email, '>');
 192                         if (!timestamp)
 193                                 die ("Could not extract author email from %s",
 194                                         sha1_to_hex(commit->object.sha1));
 195                         *timestamp = '\0';
 196                         for (timestamp++; *timestamp && isspace(*timestamp);
 197                                         timestamp++)
 198                                 ; /* do nothing */
 199                         setenv("GIT_AUTHOR_NAME", line, 1);
 200                         setenv("GIT_AUTHOR_EMAIL", email, 1);
 201                         setenv("GIT_AUTHOR_DATE", timestamp, 1);
 202                         free(line);
 203                         return;
 204                 }
 205                 p = eol;
 206                 if (*p == '\n')
 207                         p++;
 208         }
 209         die ("No author information found in %s",
 210                         sha1_to_hex(commit->object.sha1));
 211 }
 212
 213 static int merge_recursive(const char *base_sha1,
 214                 const char *head_sha1, const char *head_name,
 215                 const char *next_sha1, const char *next_name)
 216 {
 217         char buffer[256];
 218         const char *argv[6];
 219
 220         sprintf(buffer, "GITHEAD_%s", head_sha1);
 221         setenv(buffer, head_name, 1);
 222         sprintf(buffer, "GITHEAD_%s", next_sha1);
 223         setenv(buffer, next_name, 1);
 224
 225         /*
 226          * This three way merge is an interesting one.  We are at
 227          * $head, and would want to apply the change between $commit
 228          * and $prev on top of us (when reverting), or the change between
 229          * $prev and $commit on top of us (when cherry-picking or replaying).
 230          */
 231         argv[0] = "merge-recursive";
 232         argv[1] = base_sha1;
 233         argv[2] = "--";
 234         argv[3] = head_sha1;
 235         argv[4] = next_sha1;
 236         argv[5] = NULL;
 237
 238         return run_command_v_opt(argv, RUN_COMMAND_NO_STDIN | RUN_GIT_CMD);
 239 }
 240
 241 static int revert_or_cherry_pick(int argc, const char **argv)
 242 {
 243         unsigned char head[20];
 244         struct commit *base, *next, *parent;
 245         int i;
 246         char *oneline, *reencoded_message = NULL;
 247         const char *message, *encoding;
 248         const char *defmsg = xstrdup(git_path("MERGE_MSG"));
 249
 250         git_config(git_default_config);
 251         me = action == REVERT ? "revert" : "cherry-pick";
 252         setenv(GIT_REFLOG_ACTION, me, 0);
 253         parse_options(argc, argv);
 254
 255         /* this is copied from the shell script, but it's never triggered... */
 256         if (action == REVERT && replay)
 257                 die("revert is incompatible with replay");
 258
 259         if (no_commit) {
 260                 /*
 261                  * We do not intend to commit immediately.  We just want to
 262                  * merge the differences in.
 263                  */
 264                 if (write_tree(head, 0, NULL))
 265                         die ("Your index file is unmerged.");
 266         } else {
 267                 struct wt_status s;
 268
 269                 if (get_sha1("HEAD", head))
 270                         die ("You do not have a valid HEAD");
 271                 wt_status_prepare(&s);
 272                 if (s.commitable || s.workdir_dirty)
 273                         die ("Dirty index: cannot %s", me);
 274                 discard_cache();
 275         }
 276
 277         if (!commit->parents)
 278                 die ("Cannot %s a root commit", me);
 279         if (commit->parents->next) {
 280                 /* Reverting or cherry-picking a merge commit */
 281                 int cnt;
 282                 struct commit_list *p;
 283
 284                 if (!mainline)
 285                         die("Commit %s is a merge but no -m option was given.",
 286                             sha1_to_hex(commit->object.sha1));
 287
 288                 for (cnt = 1, p = commit->parents;
 289                      cnt != mainline && p;
 290                      cnt++)
 291                         p = p->next;
 292                 if (cnt != mainline || !p)
 293                         die("Commit %s does not have parent %d",
 294                             sha1_to_hex(commit->object.sha1), mainline);
 295                 parent = p->item;
 296         } else if (0 < mainline)
 297                 die("Mainline was specified but commit %s is not a merge.",
 298                     sha1_to_hex(commit->object.sha1));
 299         else
 300                 parent = commit->parents->item;
 301
 302         if (!(message = commit->buffer))
 303                 die ("Cannot get commit message for %s",
 304                                 sha1_to_hex(commit->object.sha1));
 305
 306         /*
 307          * "commit" is an existing commit.  We would want to apply
 308          * the difference it introduces since its first parent "prev"
 309          * on top of the current HEAD if we are cherry-pick.  Or the
 310          * reverse of it if we are revert.
 311          */
 312
 313         msg_fd = hold_lock_file_for_update(&msg_file, defmsg, 1);
 314
 315         encoding = get_encoding(message);
 316         if (!encoding)
 317                 encoding = "utf-8";
 318         if (!git_commit_encoding)
 319                 git_commit_encoding = "utf-8";
 320         if ((reencoded_message = reencode_string(message,
 321                                         git_commit_encoding, encoding)))
 322                 message = reencoded_message;
 323
 324         oneline = get_oneline(message);
 325
 326         if (action == REVERT) {
 327                 char *oneline_body = strchr(oneline, ' ');
 328
 329                 base = commit;
 330                 next = parent;
 331                 add_to_msg("Revert \"");
 332                 add_to_msg(oneline_body + 1);
 333                 add_to_msg("\"\n\nThis reverts commit ");
 334                 add_to_msg(sha1_to_hex(commit->object.sha1));
 335                 add_to_msg(".\n");
 336         } else {
 337                 base = parent;
 338                 next = commit;
 339                 set_author_ident_env(message);
 340                 add_message_to_msg(message);
 341                 if (!replay) {
 342                         add_to_msg("(cherry picked from commit ");
 343                         add_to_msg(sha1_to_hex(commit->object.sha1));
 344                         add_to_msg(")\n");
 345                 }
 346         }
 347         if (needed_deref) {
 348                 add_to_msg("(original 'git ");
 349                 add_to_msg(me);
 350                 add_to_msg("' arguments: ");
 351                 for (i = 0; i < argc; i++) {
 352                         if (i)
 353                                 add_to_msg(" ");
 354                         add_to_msg(argv[i]);
 355                 }
 356                 add_to_msg(")\n");
 357         }
 358
 359         if (merge_recursive(sha1_to_hex(base->object.sha1),
 360                                 sha1_to_hex(head), "HEAD",
 361                                 sha1_to_hex(next->object.sha1), oneline) ||
 362                         write_tree(head, 0, NULL)) {
 363                 add_to_msg("\nConflicts:\n\n");
 364                 read_cache();
 365                 for (i = 0; i < active_nr;) {
 366                         struct cache_entry *ce = active_cache[i++];
 367                         if (ce_stage(ce)) {
 368                                 add_to_msg("\t");
 369                                 add_to_msg(ce->name);
 370                                 add_to_msg("\n");
 371                                 while (i < active_nr && !strcmp(ce->name,
 372                                                 active_cache[i]->name))
 373                                         i++;
 374                         }
 375                 }
 376                 if (close(msg_fd) || commit_lock_file(&msg_file) < 0)
 377                         die ("Error wrapping up %s", defmsg);
 378                 fprintf(stderr, "Automatic %s failed.  "
 379                         "After resolving the conflicts,\n"
 380                         "mark the corrected paths with 'git-add <paths>'\n"
 381                         "and commit the result.\n", me);
 382                 if (action == CHERRY_PICK) {
 383                         fprintf(stderr, "When commiting, use the option "
 384                                 "'-c %s' to retain authorship and message.\n",
 385                                 find_unique_abbrev(commit->object.sha1,
 386                                         DEFAULT_ABBREV));
 387                 }
 388                 exit(1);
 389         }
 390         if (close(msg_fd) || commit_lock_file(&msg_file) < 0)
 391                 die ("Error wrapping up %s", defmsg);
 392         fprintf(stderr, "Finished one %s.\n", me);
 393
 394         /*
 395          *
 396          * If we are cherry-pick, and if the merge did not result in
 397          * hand-editing, we will hit this commit and inherit the original
 398          * author date and name.
 399          * If we are revert, or if our cherry-pick results in a hand merge,
 400          * we had better say that the current user is responsible for that.
 401          */
 402
 403         if (!no_commit) {
 404                 if (edit)
 405                         return execl_git_cmd("commit", "-n", NULL);
 406                 else
 407                         return execl_git_cmd("commit", "-n", "-F", defmsg, NULL);
 408         }
 409         if (reencoded_message)
 410                 free(reencoded_message);
 411
 412         return 0;
 413 }
 414
 415 int cmd_revert(int argc, const char **argv, const char *prefix)
 416 {
 417         if (isatty(0))
 418                 edit = 1;
 419         action = REVERT;
 420         return revert_or_cherry_pick(argc, argv);
 421 }
 422
 423 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
 424 {
 425         replay = 1;
 426         action = CHERRY_PICK;
 427         return revert_or_cherry_pick(argc, argv);
 428 }