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 "diff.h"
  12 #include "revision.h"
  13
  14 /*
  15  * This implements the builtins revert and cherry-pick.
  16  *
  17  * Copyright (c) 2007 Johannes E. Schindelin
  18  *
  19  * Based on git-revert.sh, which is
  20  *
  21  * Copyright (c) 2005 Linus Torvalds
  22  * Copyright (c) 2005 Junio C Hamano
  23  */
  24
  25 static const char * const revert_usage[] = {
  26         "git-revert [options] <commit-ish>",
  27         NULL
  28 };
  29
  30 static const char * const cherry_pick_usage[] = {
  31         "git-cherry-pick [options] <commit-ish>",
  32         NULL
  33 };
  34
  35 static int edit, no_replay, no_commit, mainline;
  36 static enum { REVERT, CHERRY_PICK } action;
  37 static struct commit *commit;
  38
  39 static const char *me;
  40
  41 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
  42
  43 static void parse_args(int argc, const char **argv)
  44 {
  45         const char * const * usage_str =
  46                 action == REVERT ?  revert_usage : cherry_pick_usage;
  47         unsigned char sha1[20];
  48         const char *arg;
  49         int noop;
  50         struct option options[] = {
  51                 OPT_BOOLEAN('n', "no-commit", &no_commit, "don't automatically commit"),
  52                 OPT_BOOLEAN('e', "edit", &edit, "edit the commit message"),
  53                 OPT_BOOLEAN('x', NULL, &no_replay, "append commit name when cherry-picking"),
  54                 OPT_BOOLEAN('r', NULL, &noop, "no-op (backward compatibility)"),
  55                 OPT_INTEGER('m', "mainline", &mainline, "parent number"),
  56                 OPT_END(),
  57         };
  58
  59         if (parse_options(argc, argv, options, usage_str, 0) != 1)
  60                 usage_with_options(usage_str, options);
  61         arg = argv[0];
  62
  63         if (get_sha1(arg, sha1))
  64                 die ("Cannot find '%s'", arg);
  65         commit = (struct commit *)parse_object(sha1);
  66         if (!commit)
  67                 die ("Could not find %s", sha1_to_hex(sha1));
  68         if (commit->object.type == OBJ_TAG) {
  69                 commit = (struct commit *)
  70                         deref_tag((struct object *)commit, arg, strlen(arg));
  71         }
  72         if (commit->object.type != OBJ_COMMIT)
  73                 die ("'%s' does not point to a commit", arg);
  74 }
  75
  76 static char *get_oneline(const char *message)
  77 {
  78         char *result;
  79         const char *p = message, *abbrev, *eol;
  80         int abbrev_len, oneline_len;
  81
  82         if (!p)
  83                 die ("Could not read commit message of %s",
  84                                 sha1_to_hex(commit->object.sha1));
  85         while (*p && (*p != '\n' || p[1] != '\n'))
  86                 p++;
  87
  88         if (*p) {
  89                 p += 2;
  90                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
  91                         ; /* do nothing */
  92         } else
  93                 eol = p;
  94         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
  95         abbrev_len = strlen(abbrev);
  96         oneline_len = eol - p;
  97         result = xmalloc(abbrev_len + 5 + oneline_len);
  98         memcpy(result, abbrev, abbrev_len);
  99         memcpy(result + abbrev_len, "... ", 4);
 100         memcpy(result + abbrev_len + 4, p, oneline_len);
 101         result[abbrev_len + 4 + oneline_len] = '\0';
 102         return result;
 103 }
 104
 105 static char *get_encoding(const char *message)
 106 {
 107         const char *p = message, *eol;
 108
 109         if (!p)
 110                 die ("Could not read commit message of %s",
 111                                 sha1_to_hex(commit->object.sha1));
 112         while (*p && *p != '\n') {
 113                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
 114                         ; /* do nothing */
 115                 if (!prefixcmp(p, "encoding ")) {
 116                         char *result = xmalloc(eol - 8 - p);
 117                         strlcpy(result, p + 9, eol - 8 - p);
 118                         return result;
 119                 }
 120                 p = eol;
 121                 if (*p == '\n')
 122                         p++;
 123         }
 124         return NULL;
 125 }
 126
 127 static struct lock_file msg_file;
 128 static int msg_fd;
 129
 130 static void add_to_msg(const char *string)
 131 {
 132         int len = strlen(string);
 133         if (write_in_full(msg_fd, string, len) < 0)
 134                 die ("Could not write to MERGE_MSG");
 135 }
 136
 137 static void add_message_to_msg(const char *message)
 138 {
 139         const char *p = message;
 140         while (*p && (*p != '\n' || p[1] != '\n'))
 141                 p++;
 142
 143         if (!*p)
 144                 add_to_msg(sha1_to_hex(commit->object.sha1));
 145
 146         p += 2;
 147         add_to_msg(p);
 148         return;
 149 }
 150
 151 static void set_author_ident_env(const char *message)
 152 {
 153         const char *p = message;
 154         if (!p)
 155                 die ("Could not read commit message of %s",
 156                                 sha1_to_hex(commit->object.sha1));
 157         while (*p && *p != '\n') {
 158                 const char *eol;
 159
 160                 for (eol = p; *eol && *eol != '\n'; eol++)
 161                         ; /* do nothing */
 162                 if (!prefixcmp(p, "author ")) {
 163                         char *line, *pend, *email, *timestamp;
 164
 165                         p += 7;
 166                         line = xmemdupz(p, eol - p);
 167                         email = strchr(line, '<');
 168                         if (!email)
 169                                 die ("Could not extract author email from %s",
 170                                         sha1_to_hex(commit->object.sha1));
 171                         if (email == line)
 172                                 pend = line;
 173                         else
 174                                 for (pend = email; pend != line + 1 &&
 175                                                 isspace(pend[-1]); pend--);
 176                                         ; /* do nothing */
 177                         *pend = '\0';
 178                         email++;
 179                         timestamp = strchr(email, '>');
 180                         if (!timestamp)
 181                                 die ("Could not extract author email from %s",
 182                                         sha1_to_hex(commit->object.sha1));
 183                         *timestamp = '\0';
 184                         for (timestamp++; *timestamp && isspace(*timestamp);
 185                                         timestamp++)
 186                                 ; /* do nothing */
 187                         setenv("GIT_AUTHOR_NAME", line, 1);
 188                         setenv("GIT_AUTHOR_EMAIL", email, 1);
 189                         setenv("GIT_AUTHOR_DATE", timestamp, 1);
 190                         free(line);
 191                         return;
 192                 }
 193                 p = eol;
 194                 if (*p == '\n')
 195                         p++;
 196         }
 197         die ("No author information found in %s",
 198                         sha1_to_hex(commit->object.sha1));
 199 }
 200
 201 static int merge_recursive(const char *base_sha1,
 202                 const char *head_sha1, const char *head_name,
 203                 const char *next_sha1, const char *next_name)
 204 {
 205         char buffer[256];
 206         const char *argv[6];
 207
 208         sprintf(buffer, "GITHEAD_%s", head_sha1);
 209         setenv(buffer, head_name, 1);
 210         sprintf(buffer, "GITHEAD_%s", next_sha1);
 211         setenv(buffer, next_name, 1);
 212
 213         /*
 214          * This three way merge is an interesting one.  We are at
 215          * $head, and would want to apply the change between $commit
 216          * and $prev on top of us (when reverting), or the change between
 217          * $prev and $commit on top of us (when cherry-picking or replaying).
 218          */
 219         argv[0] = "merge-recursive";
 220         argv[1] = base_sha1;
 221         argv[2] = "--";
 222         argv[3] = head_sha1;
 223         argv[4] = next_sha1;
 224         argv[5] = NULL;
 225
 226         return run_command_v_opt(argv, RUN_COMMAND_NO_STDIN | RUN_GIT_CMD);
 227 }
 228
 229 static char *help_msg(const unsigned char *sha1)
 230 {
 231         static char helpbuf[1024];
 232         char *msg = getenv("GIT_CHERRY_PICK_HELP");
 233
 234         if (msg)
 235                 return msg;
 236
 237         strcpy(helpbuf, "  After resolving the conflicts,\n"
 238                "mark the corrected paths with 'git add <paths>' "
 239                "or 'git rm <paths>' and commit the result.");
 240
 241         if (action == CHERRY_PICK) {
 242                 sprintf(helpbuf + strlen(helpbuf),
 243                         "\nWhen commiting, use the option "
 244                         "'-c %s' to retain authorship and message.",
 245                         find_unique_abbrev(sha1, DEFAULT_ABBREV));
 246         }
 247         return helpbuf;
 248 }
 249
 250 static int index_is_dirty(void)
 251 {
 252         struct rev_info rev;
 253         init_revisions(&rev, NULL);
 254         setup_revisions(0, NULL, &rev, "HEAD");
 255         DIFF_OPT_SET(&rev.diffopt, QUIET);
 256         DIFF_OPT_SET(&rev.diffopt, EXIT_WITH_STATUS);
 257         run_diff_index(&rev, 1);
 258         return !!DIFF_OPT_TST(&rev.diffopt, HAS_CHANGES);
 259 }
 260
 261 static int revert_or_cherry_pick(int argc, const char **argv)
 262 {
 263         unsigned char head[20];
 264         struct commit *base, *next, *parent;
 265         int i;
 266         char *oneline, *reencoded_message = NULL;
 267         const char *message, *encoding;
 268         const char *defmsg = xstrdup(git_path("MERGE_MSG"));
 269
 270         git_config(git_default_config);
 271         me = action == REVERT ? "revert" : "cherry-pick";
 272         setenv(GIT_REFLOG_ACTION, me, 0);
 273         parse_args(argc, argv);
 274
 275         /* this is copied from the shell script, but it's never triggered... */
 276         if (action == REVERT && !no_replay)
 277                 die("revert is incompatible with replay");
 278
 279         if (no_commit) {
 280                 /*
 281                  * We do not intend to commit immediately.  We just want to
 282                  * merge the differences in, so let's compute the tree
 283                  * that represents the "current" state for merge-recursive
 284                  * to work on.
 285                  */
 286                 if (write_tree(head, 0, NULL))
 287                         die ("Your index file is unmerged.");
 288         } else {
 289                 if (get_sha1("HEAD", head))
 290                         die ("You do not have a valid HEAD");
 291                 if (read_cache() < 0)
 292                         die("could not read the index");
 293                 if (index_is_dirty())
 294                         die ("Dirty index: cannot %s", me);
 295                 discard_cache();
 296         }
 297
 298         if (!commit->parents)
 299                 die ("Cannot %s a root commit", me);
 300         if (commit->parents->next) {
 301                 /* Reverting or cherry-picking a merge commit */
 302                 int cnt;
 303                 struct commit_list *p;
 304
 305                 if (!mainline)
 306                         die("Commit %s is a merge but no -m option was given.",
 307                             sha1_to_hex(commit->object.sha1));
 308
 309                 for (cnt = 1, p = commit->parents;
 310                      cnt != mainline && p;
 311                      cnt++)
 312                         p = p->next;
 313                 if (cnt != mainline || !p)
 314                         die("Commit %s does not have parent %d",
 315                             sha1_to_hex(commit->object.sha1), mainline);
 316                 parent = p->item;
 317         } else if (0 < mainline)
 318                 die("Mainline was specified but commit %s is not a merge.",
 319                     sha1_to_hex(commit->object.sha1));
 320         else
 321                 parent = commit->parents->item;
 322
 323         if (!(message = commit->buffer))
 324                 die ("Cannot get commit message for %s",
 325                                 sha1_to_hex(commit->object.sha1));
 326
 327         /*
 328          * "commit" is an existing commit.  We would want to apply
 329          * the difference it introduces since its first parent "prev"
 330          * on top of the current HEAD if we are cherry-pick.  Or the
 331          * reverse of it if we are revert.
 332          */
 333
 334         msg_fd = hold_lock_file_for_update(&msg_file, defmsg, 1);
 335
 336         encoding = get_encoding(message);
 337         if (!encoding)
 338                 encoding = "utf-8";
 339         if (!git_commit_encoding)
 340                 git_commit_encoding = "utf-8";
 341         if ((reencoded_message = reencode_string(message,
 342                                         git_commit_encoding, encoding)))
 343                 message = reencoded_message;
 344
 345         oneline = get_oneline(message);
 346
 347         if (action == REVERT) {
 348                 char *oneline_body = strchr(oneline, ' ');
 349
 350                 base = commit;
 351                 next = parent;
 352                 add_to_msg("Revert \"");
 353                 add_to_msg(oneline_body + 1);
 354                 add_to_msg("\"\n\nThis reverts commit ");
 355                 add_to_msg(sha1_to_hex(commit->object.sha1));
 356                 add_to_msg(".\n");
 357         } else {
 358                 base = parent;
 359                 next = commit;
 360                 set_author_ident_env(message);
 361                 add_message_to_msg(message);
 362                 if (no_replay) {
 363                         add_to_msg("(cherry picked from commit ");
 364                         add_to_msg(sha1_to_hex(commit->object.sha1));
 365                         add_to_msg(")\n");
 366                 }
 367         }
 368
 369         if (merge_recursive(sha1_to_hex(base->object.sha1),
 370                                 sha1_to_hex(head), "HEAD",
 371                                 sha1_to_hex(next->object.sha1), oneline) ||
 372                         write_tree(head, 0, NULL)) {
 373                 add_to_msg("\nConflicts:\n\n");
 374                 read_cache();
 375                 for (i = 0; i < active_nr;) {
 376                         struct cache_entry *ce = active_cache[i++];
 377                         if (ce_stage(ce)) {
 378                                 add_to_msg("\t");
 379                                 add_to_msg(ce->name);
 380                                 add_to_msg("\n");
 381                                 while (i < active_nr && !strcmp(ce->name,
 382                                                 active_cache[i]->name))
 383                                         i++;
 384                         }
 385                 }
 386                 if (commit_lock_file(&msg_file) < 0)
 387                         die ("Error wrapping up %s", defmsg);
 388                 fprintf(stderr, "Automatic %s failed.%s\n",
 389                         me, help_msg(commit->object.sha1));
 390                 exit(1);
 391         }
 392         if (commit_lock_file(&msg_file) < 0)
 393                 die ("Error wrapping up %s", defmsg);
 394         fprintf(stderr, "Finished one %s.\n", me);
 395
 396         /*
 397          *
 398          * If we are cherry-pick, and if the merge did not result in
 399          * hand-editing, we will hit this commit and inherit the original
 400          * author date and name.
 401          * If we are revert, or if our cherry-pick results in a hand merge,
 402          * we had better say that the current user is responsible for that.
 403          */
 404
 405         if (!no_commit) {
 406                 if (edit)
 407                         return execl_git_cmd("commit", "-n", NULL);
 408                 else
 409                         return execl_git_cmd("commit", "-n", "-F", defmsg, NULL);
 410         }
 411         if (reencoded_message)
 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 }