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;
  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_INTEGER('m', "mainline", &mainline, "parent number"),
  57                 OPT_END(),
  58         };
  59
  60         if (parse_options(argc, argv, options, usage_str, 0) != 1)
  61                 usage_with_options(usage_str, options);
  62         arg = argv[0];
  63
  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         }
  73         if (commit->object.type != OBJ_COMMIT)
  74                 die ("'%s' does not point to a commit", arg);
  75 }
  76
  77 static char *get_oneline(const char *message)
  78 {
  79         char *result;
  80         const char *p = message, *abbrev, *eol;
  81         int abbrev_len, oneline_len;
  82
  83         if (!p)
  84                 die ("Could not read commit message of %s",
  85                                 sha1_to_hex(commit->object.sha1));
  86         while (*p && (*p != '\n' || p[1] != '\n'))
  87                 p++;
  88
  89         if (*p) {
  90                 p += 2;
  91                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
  92                         ; /* do nothing */
  93         } else
  94                 eol = p;
  95         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
  96         abbrev_len = strlen(abbrev);
  97         oneline_len = eol - p;
  98         result = xmalloc(abbrev_len + 5 + oneline_len);
  99         memcpy(result, abbrev, abbrev_len);
 100         memcpy(result + abbrev_len, "... ", 4);
 101         memcpy(result + abbrev_len + 4, p, oneline_len);
 102         result[abbrev_len + 4 + oneline_len] = '\0';
 103         return result;
 104 }
 105
 106 static char *get_encoding(const char *message)
 107 {
 108         const char *p = message, *eol;
 109
 110         if (!p)
 111                 die ("Could not read commit message of %s",
 112                                 sha1_to_hex(commit->object.sha1));
 113         while (*p && *p != '\n') {
 114                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
 115                         ; /* do nothing */
 116                 if (!prefixcmp(p, "encoding ")) {
 117                         char *result = xmalloc(eol - 8 - p);
 118                         strlcpy(result, p + 9, eol - 8 - p);
 119                         return result;
 120                 }
 121                 p = eol;
 122                 if (*p == '\n')
 123                         p++;
 124         }
 125         return NULL;
 126 }
 127
 128 static struct lock_file msg_file;
 129 static int msg_fd;
 130
 131 static void add_to_msg(const char *string)
 132 {
 133         int len = strlen(string);
 134         if (write_in_full(msg_fd, string, len) < 0)
 135                 die ("Could not write to MERGE_MSG");
 136 }
 137
 138 static void add_message_to_msg(const char *message)
 139 {
 140         const char *p = message;
 141         while (*p && (*p != '\n' || p[1] != '\n'))
 142                 p++;
 143
 144         if (!*p)
 145                 add_to_msg(sha1_to_hex(commit->object.sha1));
 146
 147         p += 2;
 148         add_to_msg(p);
 149         return;
 150 }
 151
 152 static void set_author_ident_env(const char *message)
 153 {
 154         const char *p = message;
 155         if (!p)
 156                 die ("Could not read commit message of %s",
 157                                 sha1_to_hex(commit->object.sha1));
 158         while (*p && *p != '\n') {
 159                 const char *eol;
 160
 161                 for (eol = p; *eol && *eol != '\n'; eol++)
 162                         ; /* do nothing */
 163                 if (!prefixcmp(p, "author ")) {
 164                         char *line, *pend, *email, *timestamp;
 165
 166                         p += 7;
 167                         line = xmemdupz(p, eol - p);
 168                         email = strchr(line, '<');
 169                         if (!email)
 170                                 die ("Could not extract author email from %s",
 171                                         sha1_to_hex(commit->object.sha1));
 172                         if (email == line)
 173                                 pend = line;
 174                         else
 175                                 for (pend = email; pend != line + 1 &&
 176                                                 isspace(pend[-1]); pend--);
 177                                         ; /* do nothing */
 178                         *pend = '\0';
 179                         email++;
 180                         timestamp = strchr(email, '>');
 181                         if (!timestamp)
 182                                 die ("Could not extract author email from %s",
 183                                         sha1_to_hex(commit->object.sha1));
 184                         *timestamp = '\0';
 185                         for (timestamp++; *timestamp && isspace(*timestamp);
 186                                         timestamp++)
 187                                 ; /* do nothing */
 188                         setenv("GIT_AUTHOR_NAME", line, 1);
 189                         setenv("GIT_AUTHOR_EMAIL", email, 1);
 190                         setenv("GIT_AUTHOR_DATE", timestamp, 1);
 191                         free(line);
 192                         return;
 193                 }
 194                 p = eol;
 195                 if (*p == '\n')
 196                         p++;
 197         }
 198         die ("No author information found in %s",
 199                         sha1_to_hex(commit->object.sha1));
 200 }
 201
 202 static int merge_recursive(const char *base_sha1,
 203                 const char *head_sha1, const char *head_name,
 204                 const char *next_sha1, const char *next_name)
 205 {
 206         char buffer[256];
 207         const char *argv[6];
 208
 209         sprintf(buffer, "GITHEAD_%s", head_sha1);
 210         setenv(buffer, head_name, 1);
 211         sprintf(buffer, "GITHEAD_%s", next_sha1);
 212         setenv(buffer, next_name, 1);
 213
 214         /*
 215          * This three way merge is an interesting one.  We are at
 216          * $head, and would want to apply the change between $commit
 217          * and $prev on top of us (when reverting), or the change between
 218          * $prev and $commit on top of us (when cherry-picking or replaying).
 219          */
 220         argv[0] = "merge-recursive";
 221         argv[1] = base_sha1;
 222         argv[2] = "--";
 223         argv[3] = head_sha1;
 224         argv[4] = next_sha1;
 225         argv[5] = NULL;
 226
 227         return run_command_v_opt(argv, RUN_COMMAND_NO_STDIN | RUN_GIT_CMD);
 228 }
 229
 230 static char *help_msg(const unsigned char *sha1)
 231 {
 232         static char helpbuf[1024];
 233         char *msg = getenv("GIT_CHERRY_PICK_HELP");
 234
 235         if (msg)
 236                 return msg;
 237
 238         strcpy(helpbuf, "  After resolving the conflicts,\n"
 239                "mark the corrected paths with 'git add <paths>' "
 240                "or 'git rm <paths>' and commit the result.");
 241
 242         if (action == CHERRY_PICK) {
 243                 sprintf(helpbuf + strlen(helpbuf),
 244                         "\nWhen commiting, use the option "
 245                         "'-c %s' to retain authorship and message.",
 246                         find_unique_abbrev(sha1, DEFAULT_ABBREV));
 247         }
 248         return helpbuf;
 249 }
 250
 251 static int index_is_dirty(void)
 252 {
 253         struct rev_info rev;
 254         init_revisions(&rev, NULL);
 255         setup_revisions(0, NULL, &rev, "HEAD");
 256         DIFF_OPT_SET(&rev.diffopt, QUIET);
 257         DIFF_OPT_SET(&rev.diffopt, EXIT_WITH_STATUS);
 258         run_diff_index(&rev, 1);
 259         return !!DIFF_OPT_TST(&rev.diffopt, HAS_CHANGES);
 260 }
 261
 262 static int revert_or_cherry_pick(int argc, const char **argv)
 263 {
 264         unsigned char head[20];
 265         struct commit *base, *next, *parent;
 266         int i;
 267         char *oneline, *reencoded_message = NULL;
 268         const char *message, *encoding;
 269         const char *defmsg = xstrdup(git_path("MERGE_MSG"));
 270
 271         git_config(git_default_config);
 272         me = action == REVERT ? "revert" : "cherry-pick";
 273         setenv(GIT_REFLOG_ACTION, me, 0);
 274         parse_args(argc, argv);
 275
 276         /* this is copied from the shell script, but it's never triggered... */
 277         if (action == REVERT && !no_replay)
 278                 die("revert is incompatible with replay");
 279
 280         if (no_commit) {
 281                 /*
 282                  * We do not intend to commit immediately.  We just want to
 283                  * merge the differences in, so let's compute the tree
 284                  * that represents the "current" state for merge-recursive
 285                  * to work on.
 286                  */
 287                 if (write_cache_as_tree(head, 0, NULL))
 288                         die ("Your index file is unmerged.");
 289         } else {
 290                 if (get_sha1("HEAD", head))
 291                         die ("You do not have a valid HEAD");
 292                 if (read_cache() < 0)
 293                         die("could not read the index");
 294                 if (index_is_dirty())
 295                         die ("Dirty index: cannot %s", me);
 296                 discard_cache();
 297         }
 298
 299         if (!commit->parents)
 300                 die ("Cannot %s a root commit", me);
 301         if (commit->parents->next) {
 302                 /* Reverting or cherry-picking a merge commit */
 303                 int cnt;
 304                 struct commit_list *p;
 305
 306                 if (!mainline)
 307                         die("Commit %s is a merge but no -m option was given.",
 308                             sha1_to_hex(commit->object.sha1));
 309
 310                 for (cnt = 1, p = commit->parents;
 311                      cnt != mainline && p;
 312                      cnt++)
 313                         p = p->next;
 314                 if (cnt != mainline || !p)
 315                         die("Commit %s does not have parent %d",
 316                             sha1_to_hex(commit->object.sha1), mainline);
 317                 parent = p->item;
 318         } else if (0 < mainline)
 319                 die("Mainline was specified but commit %s is not a merge.",
 320                     sha1_to_hex(commit->object.sha1));
 321         else
 322                 parent = commit->parents->item;
 323
 324         if (!(message = commit->buffer))
 325                 die ("Cannot get commit message for %s",
 326                                 sha1_to_hex(commit->object.sha1));
 327
 328         /*
 329          * "commit" is an existing commit.  We would want to apply
 330          * the difference it introduces since its first parent "prev"
 331          * on top of the current HEAD if we are cherry-pick.  Or the
 332          * reverse of it if we are revert.
 333          */
 334
 335         msg_fd = hold_lock_file_for_update(&msg_file, defmsg, 1);
 336
 337         encoding = get_encoding(message);
 338         if (!encoding)
 339                 encoding = "utf-8";
 340         if (!git_commit_encoding)
 341                 git_commit_encoding = "utf-8";
 342         if ((reencoded_message = reencode_string(message,
 343                                         git_commit_encoding, encoding)))
 344                 message = reencoded_message;
 345
 346         oneline = get_oneline(message);
 347
 348         if (action == REVERT) {
 349                 char *oneline_body = strchr(oneline, ' ');
 350
 351                 base = commit;
 352                 next = parent;
 353                 add_to_msg("Revert \"");
 354                 add_to_msg(oneline_body + 1);
 355                 add_to_msg("\"\n\nThis reverts commit ");
 356                 add_to_msg(sha1_to_hex(commit->object.sha1));
 357                 add_to_msg(".\n");
 358         } else {
 359                 base = parent;
 360                 next = commit;
 361                 set_author_ident_env(message);
 362                 add_message_to_msg(message);
 363                 if (no_replay) {
 364                         add_to_msg("(cherry picked from commit ");
 365                         add_to_msg(sha1_to_hex(commit->object.sha1));
 366                         add_to_msg(")\n");
 367                 }
 368         }
 369
 370         if (merge_recursive(sha1_to_hex(base->object.sha1),
 371                                 sha1_to_hex(head), "HEAD",
 372                                 sha1_to_hex(next->object.sha1), oneline) ||
 373                         write_cache_as_tree(head, 0, NULL)) {
 374                 add_to_msg("\nConflicts:\n\n");
 375                 read_cache();
 376                 for (i = 0; i < active_nr;) {
 377                         struct cache_entry *ce = active_cache[i++];
 378                         if (ce_stage(ce)) {
 379                                 add_to_msg("\t");
 380                                 add_to_msg(ce->name);
 381                                 add_to_msg("\n");
 382                                 while (i < active_nr && !strcmp(ce->name,
 383                                                 active_cache[i]->name))
 384                                         i++;
 385                         }
 386                 }
 387                 if (commit_lock_file(&msg_file) < 0)
 388                         die ("Error wrapping up %s", defmsg);
 389                 fprintf(stderr, "Automatic %s failed.%s\n",
 390                         me, help_msg(commit->object.sha1));
 391                 exit(1);
 392         }
 393         if (commit_lock_file(&msg_file) < 0)
 394                 die ("Error wrapping up %s", defmsg);
 395         fprintf(stderr, "Finished one %s.\n", me);
 396
 397         /*
 398          *
 399          * If we are cherry-pick, and if the merge did not result in
 400          * hand-editing, we will hit this commit and inherit the original
 401          * author date and name.
 402          * If we are revert, or if our cherry-pick results in a hand merge,
 403          * we had better say that the current user is responsible for that.
 404          */
 405
 406         if (!no_commit) {
 407                 if (edit)
 408                         return execl_git_cmd("commit", "-n", NULL);
 409                 else
 410                         return execl_git_cmd("commit", "-n", "-F", defmsg, NULL);
 411         }
 412         free(reencoded_message);
 413
 414         return 0;
 415 }
 416
 417 int cmd_revert(int argc, const char **argv, const char *prefix)
 418 {
 419         if (isatty(0))
 420                 edit = 1;
 421         no_replay = 1;
 422         action = REVERT;
 423         return revert_or_cherry_pick(argc, argv);
 424 }
 425
 426 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
 427 {
 428         no_replay = 0;
 429         action = CHERRY_PICK;
 430         return revert_or_cherry_pick(argc, argv);
 431 }