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] <commit-ish>";
  23
  24 static const char *cherry_pick_usage = "git-cherry-pick [--edit] [-n] [-r] [-x] <commit-ish>";
  25
  26 static int edit;
  27 static int replay;
  28 enum { REVERT, CHERRY_PICK } action;
  29 static int no_commit;
  30 static struct commit *commit;
  31 static int needed_deref;
  32
  33 static const char *me;
  34
  35 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
  36
  37 static void parse_options(int argc, const char **argv)
  38 {
  39         const char *usage_str = action == REVERT ?
  40                 revert_usage : cherry_pick_usage;
  41         unsigned char sha1[20];
  42         const char *arg;
  43         int i;
  44
  45         if (argc < 2)
  46                 usage(usage_str);
  47
  48         for (i = 1; i < argc - 1; i++) {
  49                 arg = argv[i];
  50                 if (!strcmp(arg, "-n") || !strcmp(arg, "--no-commit"))
  51                         no_commit = 1;
  52                 else if (!strcmp(arg, "-e") || !strcmp(arg, "--edit"))
  53                         edit = 1;
  54                 else if (!strcmp(arg, "--no-edit"))
  55                         edit = 0;
  56                 else if (!strcmp(arg, "-x") || !strcmp(arg, "--i-really-want-"
  57                                 "to-expose-my-private-commit-object-name"))
  58                         replay = 0;
  59                 else if (strcmp(arg, "-r"))
  60                         usage(usage_str);
  61         }
  62
  63         arg = argv[argc - 1];
  64         if (get_sha1(arg, sha1))
  65                 die ("Cannot find '%s'", arg);
  66         commit = (struct commit *)parse_object(sha1);
  67         if (!commit)
  68                 die ("Could not find %s", sha1_to_hex(sha1));
  69         if (commit->object.type == OBJ_TAG) {
  70                 commit = (struct commit *)
  71                         deref_tag((struct object *)commit, arg, strlen(arg));
  72                 needed_deref = 1;
  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 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 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 .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 = xmalloc(eol + 1 - p);
 169                         memcpy(line, p, eol - p);
 170                         line[eol - p] = '\0';
 171                         email = strchr(line, '<');
 172                         if (!email)
 173                                 die ("Could not extract author email from %s",
 174                                         sha1_to_hex(commit->object.sha1));
 175                         if (email == line)
 176                                 pend = line;
 177                         else
 178                                 for (pend = email; pend != line + 1 &&
 179                                                 isspace(pend[-1]); pend--);
 180                                         ; /* do nothing */
 181                         *pend = '\0';
 182                         email++;
 183                         timestamp = strchr(email, '>');
 184                         if (!timestamp)
 185                                 die ("Could not extract author email from %s",
 186                                         sha1_to_hex(commit->object.sha1));
 187                         *timestamp = '\0';
 188                         for (timestamp++; *timestamp && isspace(*timestamp);
 189                                         timestamp++)
 190                                 ; /* do nothing */
 191                         setenv("GIT_AUTHOR_NAME", line, 1);
 192                         setenv("GIT_AUTHOR_EMAIL", email, 1);
 193                         setenv("GIT_AUTHOR_DATE", timestamp, 1);
 194                         free(line);
 195                         return;
 196                 }
 197                 p = eol;
 198                 if (*p == '\n')
 199                         p++;
 200         }
 201         die ("No author information found in %s",
 202                         sha1_to_hex(commit->object.sha1));
 203 }
 204
 205 static int merge_recursive(const char *base_sha1,
 206                 const char *head_sha1, const char *head_name,
 207                 const char *next_sha1, const char *next_name)
 208 {
 209         char buffer[256];
 210         const char *argv[6];
 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[0] = "merge-recursive";
 224         argv[1] = base_sha1;
 225         argv[2] = "--";
 226         argv[3] = head_sha1;
 227         argv[4] = next_sha1;
 228         argv[5] = NULL;
 229
 230         return run_command_v_opt(argv, RUN_COMMAND_NO_STDIN | RUN_GIT_CMD);
 231 }
 232
 233 static int revert_or_cherry_pick(int argc, const char **argv)
 234 {
 235         unsigned char head[20];
 236         struct commit *base, *next;
 237         int i;
 238         char *oneline, *reencoded_message = NULL;
 239         const char *message, *encoding;
 240         const char *defmsg = xstrdup(git_path("MERGE_MSG"));
 241
 242         git_config(git_default_config);
 243         me = action == REVERT ? "revert" : "cherry-pick";
 244         setenv(GIT_REFLOG_ACTION, me, 0);
 245         parse_options(argc, argv);
 246
 247         /* this is copied from the shell script, but it's never triggered... */
 248         if (action == REVERT && replay)
 249                 die("revert is incompatible with replay");
 250
 251         if (no_commit) {
 252                 /*
 253                  * We do not intend to commit immediately.  We just want to
 254                  * merge the differences in.
 255                  */
 256                 if (write_tree(head, 0, NULL))
 257                         die ("Your index file is unmerged.");
 258         } else {
 259                 struct wt_status s;
 260
 261                 if (get_sha1("HEAD", head))
 262                         die ("You do not have a valid HEAD");
 263                 wt_status_prepare(&s);
 264                 if (s.commitable || s.workdir_dirty)
 265                         die ("Dirty index: cannot %s", me);
 266                 discard_cache();
 267         }
 268
 269         if (!commit->parents)
 270                 die ("Cannot %s a root commit", me);
 271         if (commit->parents->next)
 272                 die ("Cannot %s a multi-parent commit.", me);
 273         if (!(message = commit->buffer))
 274                 die ("Cannot get commit message for %s",
 275                                 sha1_to_hex(commit->object.sha1));
 276
 277         /*
 278          * "commit" is an existing commit.  We would want to apply
 279          * the difference it introduces since its first parent "prev"
 280          * on top of the current HEAD if we are cherry-pick.  Or the
 281          * reverse of it if we are revert.
 282          */
 283
 284         msg_fd = hold_lock_file_for_update(&msg_file, defmsg, 1);
 285
 286         encoding = get_encoding(message);
 287         if (!encoding)
 288                 encoding = "utf-8";
 289         if (!git_commit_encoding)
 290                 git_commit_encoding = "utf-8";
 291         if ((reencoded_message = reencode_string(message,
 292                                         git_commit_encoding, encoding)))
 293                 message = reencoded_message;
 294
 295         oneline = get_oneline(message);
 296
 297         if (action == REVERT) {
 298                 char *oneline_body = strchr(oneline, ' ');
 299
 300                 base = commit;
 301                 next = commit->parents->item;
 302                 add_to_msg("Revert \"");
 303                 add_to_msg(oneline_body + 1);
 304                 add_to_msg("\"\n\nThis reverts commit ");
 305                 add_to_msg(sha1_to_hex(commit->object.sha1));
 306                 add_to_msg(".\n");
 307         } else {
 308                 base = commit->parents->item;
 309                 next = commit;
 310                 set_author_ident_env(message);
 311                 add_message_to_msg(message);
 312                 if (!replay) {
 313                         add_to_msg("(cherry picked from commit ");
 314                         add_to_msg(sha1_to_hex(commit->object.sha1));
 315                         add_to_msg(")\n");
 316                 }
 317         }
 318         if (needed_deref) {
 319                 add_to_msg("(original 'git ");
 320                 add_to_msg(me);
 321                 add_to_msg("' arguments: ");
 322                 for (i = 0; i < argc; i++) {
 323                         if (i)
 324                                 add_to_msg(" ");
 325                         add_to_msg(argv[i]);
 326                 }
 327                 add_to_msg(")\n");
 328         }
 329
 330         if (merge_recursive(sha1_to_hex(base->object.sha1),
 331                                 sha1_to_hex(head), "HEAD",
 332                                 sha1_to_hex(next->object.sha1), oneline) ||
 333                         write_tree(head, 0, NULL)) {
 334                 add_to_msg("\nConflicts:\n\n");
 335                 read_cache();
 336                 for (i = 0; i < active_nr;) {
 337                         struct cache_entry *ce = active_cache[i++];
 338                         if (ce_stage(ce)) {
 339                                 add_to_msg("\t");
 340                                 add_to_msg(ce->name);
 341                                 add_to_msg("\n");
 342                                 while (i < active_nr && !strcmp(ce->name,
 343                                                 active_cache[i]->name))
 344                                         i++;
 345                         }
 346                 }
 347                 if (close(msg_fd) || commit_lock_file(&msg_file) < 0)
 348                         die ("Error wrapping up %s", defmsg);
 349                 fprintf(stderr, "Automatic %s failed.  "
 350                         "After resolving the conflicts,\n"
 351                         "mark the corrected paths with 'git-add <paths>'\n"
 352                         "and commit the result.\n", me);
 353                 if (action == CHERRY_PICK) {
 354                         fprintf(stderr, "When commiting, use the option "
 355                                 "'-c %s' to retain authorship and message.\n",
 356                                 find_unique_abbrev(commit->object.sha1,
 357                                         DEFAULT_ABBREV));
 358                 }
 359                 exit(1);
 360         }
 361         if (close(msg_fd) || commit_lock_file(&msg_file) < 0)
 362                 die ("Error wrapping up %s", defmsg);
 363         fprintf(stderr, "Finished one %s.\n", me);
 364
 365         /*
 366          *
 367          * If we are cherry-pick, and if the merge did not result in
 368          * hand-editing, we will hit this commit and inherit the original
 369          * author date and name.
 370          * If we are revert, or if our cherry-pick results in a hand merge,
 371          * we had better say that the current user is responsible for that.
 372          */
 373
 374         if (!no_commit) {
 375                 if (edit)
 376                         return execl_git_cmd("commit", "-n", NULL);
 377                 else
 378                         return execl_git_cmd("commit", "-n", "-F", defmsg, NULL);
 379         }
 380         if (reencoded_message)
 381                 free(reencoded_message);
 382
 383         return 0;
 384 }
 385
 386 int cmd_revert(int argc, const char **argv, const char *prefix)
 387 {
 388         if (isatty(0))
 389                 edit = 1;
 390         action = REVERT;
 391         return revert_or_cherry_pick(argc, argv);
 392 }
 393
 394 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
 395 {
 396         replay = 1;
 397         action = CHERRY_PICK;
 398         return revert_or_cherry_pick(argc, argv);
 399 }