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
  42 static const char *me;
  43
  44 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
  45
  46 static void parse_args(int argc, const char **argv)
  47 {
  48         const char * const * usage_str =
  49                 action == REVERT ?  revert_usage : cherry_pick_usage;
  50         unsigned char sha1[20];
  51         const char *arg;
  52         int noop;
  53         struct option options[] = {
  54                 OPT_BOOLEAN('n', "no-commit", &no_commit, "don't automatically commit"),
  55                 OPT_BOOLEAN('e', "edit", &edit, "edit the commit message"),
  56                 OPT_BOOLEAN('x', NULL, &no_replay, "append commit name when cherry-picking"),
  57                 OPT_BOOLEAN('r', NULL, &noop, "no-op (backward compatibility)"),
  58                 OPT_BOOLEAN('s', "signoff", &signoff, "add Signed-off-by:"),
  59                 OPT_INTEGER('m', "mainline", &mainline, "parent number"),
  60                 OPT_END(),
  61         };
  62
  63         if (parse_options(argc, argv, options, usage_str, 0) != 1)
  64                 usage_with_options(usage_str, options);
  65         arg = argv[0];
  66
  67         if (get_sha1(arg, sha1))
  68                 die ("Cannot find '%s'", arg);
  69         commit = (struct commit *)parse_object(sha1);
  70         if (!commit)
  71                 die ("Could not find %s", sha1_to_hex(sha1));
  72         if (commit->object.type == OBJ_TAG) {
  73                 commit = (struct commit *)
  74                         deref_tag((struct object *)commit, arg, strlen(arg));
  75         }
  76         if (commit->object.type != OBJ_COMMIT)
  77                 die ("'%s' does not point to a commit", arg);
  78 }
  79
  80 static char *get_oneline(const char *message)
  81 {
  82         char *result;
  83         const char *p = message, *abbrev, *eol;
  84         int abbrev_len, oneline_len;
  85
  86         if (!p)
  87                 die ("Could not read commit message of %s",
  88                                 sha1_to_hex(commit->object.sha1));
  89         while (*p && (*p != '\n' || p[1] != '\n'))
  90                 p++;
  91
  92         if (*p) {
  93                 p += 2;
  94                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
  95                         ; /* do nothing */
  96         } else
  97                 eol = p;
  98         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
  99         abbrev_len = strlen(abbrev);
 100         oneline_len = eol - p;
 101         result = xmalloc(abbrev_len + 5 + oneline_len);
 102         memcpy(result, abbrev, abbrev_len);
 103         memcpy(result + abbrev_len, "... ", 4);
 104         memcpy(result + abbrev_len + 4, p, oneline_len);
 105         result[abbrev_len + 4 + oneline_len] = '\0';
 106         return result;
 107 }
 108
 109 static char *get_encoding(const char *message)
 110 {
 111         const char *p = message, *eol;
 112
 113         if (!p)
 114                 die ("Could not read commit message of %s",
 115                                 sha1_to_hex(commit->object.sha1));
 116         while (*p && *p != '\n') {
 117                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
 118                         ; /* do nothing */
 119                 if (!prefixcmp(p, "encoding ")) {
 120                         char *result = xmalloc(eol - 8 - p);
 121                         strlcpy(result, p + 9, eol - 8 - p);
 122                         return result;
 123                 }
 124                 p = eol;
 125                 if (*p == '\n')
 126                         p++;
 127         }
 128         return NULL;
 129 }
 130
 131 static struct lock_file msg_file;
 132 static int msg_fd;
 133
 134 static void add_to_msg(const char *string)
 135 {
 136         int len = strlen(string);
 137         if (write_in_full(msg_fd, string, len) < 0)
 138                 die ("Could not write to MERGE_MSG");
 139 }
 140
 141 static void add_message_to_msg(const char *message)
 142 {
 143         const char *p = message;
 144         while (*p && (*p != '\n' || p[1] != '\n'))
 145                 p++;
 146
 147         if (!*p)
 148                 add_to_msg(sha1_to_hex(commit->object.sha1));
 149
 150         p += 2;
 151         add_to_msg(p);
 152         return;
 153 }
 154
 155 static void set_author_ident_env(const char *message)
 156 {
 157         const char *p = message;
 158         if (!p)
 159                 die ("Could not read commit message of %s",
 160                                 sha1_to_hex(commit->object.sha1));
 161         while (*p && *p != '\n') {
 162                 const char *eol;
 163
 164                 for (eol = p; *eol && *eol != '\n'; eol++)
 165                         ; /* do nothing */
 166                 if (!prefixcmp(p, "author ")) {
 167                         char *line, *pend, *email, *timestamp;
 168
 169                         p += 7;
 170                         line = xmemdupz(p, eol - p);
 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 time 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 char *help_msg(const unsigned char *sha1)
 206 {
 207         static char helpbuf[1024];
 208         char *msg = getenv("GIT_CHERRY_PICK_HELP");
 209
 210         if (msg)
 211                 return msg;
 212
 213         strcpy(helpbuf, "  After resolving the conflicts,\n"
 214                "mark the corrected paths with 'git add <paths>' "
 215                "or 'git rm <paths>' and commit the result.");
 216
 217         if (action == CHERRY_PICK) {
 218                 sprintf(helpbuf + strlen(helpbuf),
 219                         "\nWhen commiting, use the option "
 220                         "'-c %s' to retain authorship and message.",
 221                         find_unique_abbrev(sha1, DEFAULT_ABBREV));
 222         }
 223         return helpbuf;
 224 }
 225
 226 static struct tree *empty_tree(void)
 227 {
 228         struct tree *tree = xcalloc(1, sizeof(struct tree));
 229
 230         tree->object.parsed = 1;
 231         tree->object.type = OBJ_TREE;
 232         pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
 233         return tree;
 234 }
 235
 236 static int revert_or_cherry_pick(int argc, const char **argv)
 237 {
 238         unsigned char head[20];
 239         struct commit *base, *next, *parent;
 240         int i, index_fd, clean;
 241         char *oneline, *reencoded_message = NULL;
 242         const char *message, *encoding;
 243         char *defmsg = git_pathdup("MERGE_MSG");
 244         struct merge_options o;
 245         struct tree *result, *next_tree, *base_tree, *head_tree;
 246         static struct lock_file index_lock;
 247
 248         git_config(git_default_config, NULL);
 249         me = action == REVERT ? "revert" : "cherry-pick";
 250         setenv(GIT_REFLOG_ACTION, me, 0);
 251         parse_args(argc, argv);
 252
 253         /* this is copied from the shell script, but it's never triggered... */
 254         if (action == REVERT && !no_replay)
 255                 die("revert is incompatible with replay");
 256
 257         if (read_cache() < 0)
 258                 die("git %s: failed to read the index", me);
 259         if (no_commit) {
 260                 /*
 261                  * We do not intend to commit immediately.  We just want to
 262                  * merge the differences in, so let's compute the tree
 263                  * that represents the "current" state for merge-recursive
 264                  * to work on.
 265                  */
 266                 if (write_cache_as_tree(head, 0, NULL))
 267                         die ("Your index file is unmerged.");
 268         } else {
 269                 if (get_sha1("HEAD", head))
 270                         die ("You do not have a valid HEAD");
 271                 if (index_differs_from("HEAD", 0))
 272                         die ("Dirty index: cannot %s", me);
 273         }
 274         discard_cache();
 275
 276         index_fd = hold_locked_index(&index_lock, 1);
 277
 278         if (!commit->parents) {
 279                 if (action == REVERT)
 280                         die ("Cannot revert a root commit");
 281                 parent = NULL;
 282         }
 283         else if (commit->parents->next) {
 284                 /* Reverting or cherry-picking a merge commit */
 285                 int cnt;
 286                 struct commit_list *p;
 287
 288                 if (!mainline)
 289                         die("Commit %s is a merge but no -m option was given.",
 290                             sha1_to_hex(commit->object.sha1));
 291
 292                 for (cnt = 1, p = commit->parents;
 293                      cnt != mainline && p;
 294                      cnt++)
 295                         p = p->next;
 296                 if (cnt != mainline || !p)
 297                         die("Commit %s does not have parent %d",
 298                             sha1_to_hex(commit->object.sha1), mainline);
 299                 parent = p->item;
 300         } else if (0 < mainline)
 301                 die("Mainline was specified but commit %s is not a merge.",
 302                     sha1_to_hex(commit->object.sha1));
 303         else
 304                 parent = commit->parents->item;
 305
 306         if (!(message = commit->buffer))
 307                 die ("Cannot get commit message for %s",
 308                                 sha1_to_hex(commit->object.sha1));
 309
 310         if (parent && parse_commit(parent) < 0)
 311                 die("%s: cannot parse parent commit %s",
 312                     me, sha1_to_hex(parent->object.sha1));
 313
 314         /*
 315          * "commit" is an existing commit.  We would want to apply
 316          * the difference it introduces since its first parent "prev"
 317          * on top of the current HEAD if we are cherry-pick.  Or the
 318          * reverse of it if we are revert.
 319          */
 320
 321         msg_fd = hold_lock_file_for_update(&msg_file, defmsg,
 322                                            LOCK_DIE_ON_ERROR);
 323
 324         encoding = get_encoding(message);
 325         if (!encoding)
 326                 encoding = "utf-8";
 327         if (!git_commit_encoding)
 328                 git_commit_encoding = "utf-8";
 329         if ((reencoded_message = reencode_string(message,
 330                                         git_commit_encoding, encoding)))
 331                 message = reencoded_message;
 332
 333         oneline = get_oneline(message);
 334
 335         if (action == REVERT) {
 336                 char *oneline_body = strchr(oneline, ' ');
 337
 338                 base = commit;
 339                 next = parent;
 340                 add_to_msg("Revert \"");
 341                 add_to_msg(oneline_body + 1);
 342                 add_to_msg("\"\n\nThis reverts commit ");
 343                 add_to_msg(sha1_to_hex(commit->object.sha1));
 344
 345                 if (commit->parents->next) {
 346                         add_to_msg(", reversing\nchanges made to ");
 347                         add_to_msg(sha1_to_hex(parent->object.sha1));
 348                 }
 349                 add_to_msg(".\n");
 350         } else {
 351                 base = parent;
 352                 next = commit;
 353                 set_author_ident_env(message);
 354                 add_message_to_msg(message);
 355                 if (no_replay) {
 356                         add_to_msg("(cherry picked from commit ");
 357                         add_to_msg(sha1_to_hex(commit->object.sha1));
 358                         add_to_msg(")\n");
 359                 }
 360         }
 361
 362         read_cache();
 363         init_merge_options(&o);
 364         o.branch1 = "HEAD";
 365         o.branch2 = oneline;
 366
 367         head_tree = parse_tree_indirect(head);
 368         next_tree = next ? next->tree : empty_tree();
 369         base_tree = base ? base->tree : empty_tree();
 370
 371         clean = merge_trees(&o,
 372                             head_tree,
 373                             next_tree, base_tree, &result);
 374
 375         if (active_cache_changed &&
 376             (write_cache(index_fd, active_cache, active_nr) ||
 377              commit_locked_index(&index_lock)))
 378                 die("%s: Unable to write new index file", me);
 379
 380         if (!clean) {
 381                 add_to_msg("\nConflicts:\n\n");
 382                 for (i = 0; i < active_nr;) {
 383                         struct cache_entry *ce = active_cache[i++];
 384                         if (ce_stage(ce)) {
 385                                 add_to_msg("\t");
 386                                 add_to_msg(ce->name);
 387                                 add_to_msg("\n");
 388                                 while (i < active_nr && !strcmp(ce->name,
 389                                                 active_cache[i]->name))
 390                                         i++;
 391                         }
 392                 }
 393                 if (commit_lock_file(&msg_file) < 0)
 394                         die ("Error wrapping up %s", defmsg);
 395                 fprintf(stderr, "Automatic %s failed.%s\n",
 396                         me, help_msg(commit->object.sha1));
 397                 rerere();
 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         free(defmsg);
 430
 431         return 0;
 432 }
 433
 434 int cmd_revert(int argc, const char **argv, const char *prefix)
 435 {
 436         if (isatty(0))
 437                 edit = 1;
 438         no_replay = 1;
 439         action = REVERT;
 440         return revert_or_cherry_pick(argc, argv);
 441 }
 442
 443 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
 444 {
 445         no_replay = 0;
 446         action = CHERRY_PICK;
 447         return revert_or_cherry_pick(argc, argv);
 448 }