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
  13 /*
  14  * This implements the builtins revert and cherry-pick.
  15  *
  16  * Copyright (c) 2007 Johannes E. Schindelin
  17  *
  18  * Based on git-revert.sh, which is
  19  *
  20  * Copyright (c) 2005 Linus Torvalds
  21  * Copyright (c) 2005 Junio C Hamano
  22  */
  23
  24 static const char * const revert_usage[] = {
  25         "git-revert [options] <commit-ish>",
  26         NULL
  27 };
  28
  29 static const char * const cherry_pick_usage[] = {
  30         "git-cherry-pick [options] <commit-ish>",
  31         NULL
  32 };
  33
  34 static int edit, no_replay, no_commit, mainline;
  35 static enum { REVERT, CHERRY_PICK } action;
  36 static struct commit *commit;
  37
  38 static const char *me;
  39
  40 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
  41
  42 static void parse_args(int argc, const char **argv)
  43 {
  44         const char * const * usage_str =
  45                 action == REVERT ?  revert_usage : cherry_pick_usage;
  46         unsigned char sha1[20];
  47         const char *arg;
  48         int noop;
  49         struct option options[] = {
  50                 OPT_BOOLEAN('n', "no-commit", &no_commit, "don't automatically commit"),
  51                 OPT_BOOLEAN('e', "edit", &edit, "edit the commit message"),
  52                 OPT_BOOLEAN('x', NULL, &no_replay, "append commit name when cherry-picking"),
  53                 OPT_BOOLEAN('r', NULL, &noop, "no-op (backward compatibility)"),
  54                 OPT_INTEGER('m', "mainline", &mainline, "parent number"),
  55                 OPT_END(),
  56         };
  57
  58         if (parse_options(argc, argv, options, usage_str, 0) != 1)
  59                 usage_with_options(usage_str, options);
  60         arg = argv[0];
  61
  62         if (get_sha1(arg, sha1))
  63                 die ("Cannot find '%s'", arg);
  64         commit = (struct commit *)parse_object(sha1);
  65         if (!commit)
  66                 die ("Could not find %s", sha1_to_hex(sha1));
  67         if (commit->object.type == OBJ_TAG) {
  68                 commit = (struct commit *)
  69                         deref_tag((struct object *)commit, arg, strlen(arg));
  70         }
  71         if (commit->object.type != OBJ_COMMIT)
  72                 die ("'%s' does not point to a commit", arg);
  73 }
  74
  75 static char *get_oneline(const char *message)
  76 {
  77         char *result;
  78         const char *p = message, *abbrev, *eol;
  79         int abbrev_len, oneline_len;
  80
  81         if (!p)
  82                 die ("Could not read commit message of %s",
  83                                 sha1_to_hex(commit->object.sha1));
  84         while (*p && (*p != '\n' || p[1] != '\n'))
  85                 p++;
  86
  87         if (*p) {
  88                 p += 2;
  89                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
  90                         ; /* do nothing */
  91         } else
  92                 eol = p;
  93         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
  94         abbrev_len = strlen(abbrev);
  95         oneline_len = eol - p;
  96         result = xmalloc(abbrev_len + 5 + oneline_len);
  97         memcpy(result, abbrev, abbrev_len);
  98         memcpy(result + abbrev_len, "... ", 4);
  99         memcpy(result + abbrev_len + 4, p, oneline_len);
 100         result[abbrev_len + 4 + oneline_len] = '\0';
 101         return result;
 102 }
 103
 104 static char *get_encoding(const char *message)
 105 {
 106         const char *p = message, *eol;
 107
 108         if (!p)
 109                 die ("Could not read commit message of %s",
 110                                 sha1_to_hex(commit->object.sha1));
 111         while (*p && *p != '\n') {
 112                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
 113                         ; /* do nothing */
 114                 if (!prefixcmp(p, "encoding ")) {
 115                         char *result = xmalloc(eol - 8 - p);
 116                         strlcpy(result, p + 9, eol - 8 - p);
 117                         return result;
 118                 }
 119                 p = eol;
 120                 if (*p == '\n')
 121                         p++;
 122         }
 123         return NULL;
 124 }
 125
 126 static struct lock_file msg_file;
 127 static int msg_fd;
 128
 129 static void add_to_msg(const char *string)
 130 {
 131         int len = strlen(string);
 132         if (write_in_full(msg_fd, string, len) < 0)
 133                 die ("Could not write to MERGE_MSG");
 134 }
 135
 136 static void add_message_to_msg(const char *message)
 137 {
 138         const char *p = message;
 139         while (*p && (*p != '\n' || p[1] != '\n'))
 140                 p++;
 141
 142         if (!*p)
 143                 add_to_msg(sha1_to_hex(commit->object.sha1));
 144
 145         p += 2;
 146         add_to_msg(p);
 147         return;
 148 }
 149
 150 static void set_author_ident_env(const char *message)
 151 {
 152         const char *p = message;
 153         if (!p)
 154                 die ("Could not read commit message of %s",
 155                                 sha1_to_hex(commit->object.sha1));
 156         while (*p && *p != '\n') {
 157                 const char *eol;
 158
 159                 for (eol = p; *eol && *eol != '\n'; eol++)
 160                         ; /* do nothing */
 161                 if (!prefixcmp(p, "author ")) {
 162                         char *line, *pend, *email, *timestamp;
 163
 164                         p += 7;
 165                         line = xmemdupz(p, eol - p);
 166                         email = strchr(line, '<');
 167                         if (!email)
 168                                 die ("Could not extract author email from %s",
 169                                         sha1_to_hex(commit->object.sha1));
 170                         if (email == line)
 171                                 pend = line;
 172                         else
 173                                 for (pend = email; pend != line + 1 &&
 174                                                 isspace(pend[-1]); pend--);
 175                                         ; /* do nothing */
 176                         *pend = '\0';
 177                         email++;
 178                         timestamp = strchr(email, '>');
 179                         if (!timestamp)
 180                                 die ("Could not extract author email from %s",
 181                                         sha1_to_hex(commit->object.sha1));
 182                         *timestamp = '\0';
 183                         for (timestamp++; *timestamp && isspace(*timestamp);
 184                                         timestamp++)
 185                                 ; /* do nothing */
 186                         setenv("GIT_AUTHOR_NAME", line, 1);
 187                         setenv("GIT_AUTHOR_EMAIL", email, 1);
 188                         setenv("GIT_AUTHOR_DATE", timestamp, 1);
 189                         free(line);
 190                         return;
 191                 }
 192                 p = eol;
 193                 if (*p == '\n')
 194                         p++;
 195         }
 196         die ("No author information found in %s",
 197                         sha1_to_hex(commit->object.sha1));
 198 }
 199
 200 static int merge_recursive(const char *base_sha1,
 201                 const char *head_sha1, const char *head_name,
 202                 const char *next_sha1, const char *next_name)
 203 {
 204         char buffer[256];
 205         const char *argv[6];
 206
 207         sprintf(buffer, "GITHEAD_%s", head_sha1);
 208         setenv(buffer, head_name, 1);
 209         sprintf(buffer, "GITHEAD_%s", next_sha1);
 210         setenv(buffer, next_name, 1);
 211
 212         /*
 213          * This three way merge is an interesting one.  We are at
 214          * $head, and would want to apply the change between $commit
 215          * and $prev on top of us (when reverting), or the change between
 216          * $prev and $commit on top of us (when cherry-picking or replaying).
 217          */
 218         argv[0] = "merge-recursive";
 219         argv[1] = base_sha1;
 220         argv[2] = "--";
 221         argv[3] = head_sha1;
 222         argv[4] = next_sha1;
 223         argv[5] = NULL;
 224
 225         return run_command_v_opt(argv, RUN_COMMAND_NO_STDIN | RUN_GIT_CMD);
 226 }
 227
 228 static char *help_msg(const unsigned char *sha1)
 229 {
 230         static char helpbuf[1024];
 231         char *msg = getenv("GIT_CHERRY_PICK_HELP");
 232
 233         if (msg)
 234                 return msg;
 235
 236         strcpy(helpbuf, "  After resolving the conflicts,\n"
 237                "mark the corrected paths with 'git add <paths>' "
 238                "or 'git rm <paths>' and commit the result.");
 239
 240         if (action == CHERRY_PICK) {
 241                 sprintf(helpbuf + strlen(helpbuf),
 242                         "\nWhen commiting, use the option "
 243                         "'-c %s' to retain authorship and message.",
 244                         find_unique_abbrev(sha1, DEFAULT_ABBREV));
 245         }
 246         return helpbuf;
 247 }
 248
 249 static int revert_or_cherry_pick(int argc, const char **argv)
 250 {
 251         unsigned char head[20];
 252         struct commit *base, *next, *parent;
 253         int i;
 254         char *oneline, *reencoded_message = NULL;
 255         const char *message, *encoding;
 256         const char *defmsg = xstrdup(git_path("MERGE_MSG"));
 257
 258         git_config(git_default_config);
 259         me = action == REVERT ? "revert" : "cherry-pick";
 260         setenv(GIT_REFLOG_ACTION, me, 0);
 261         parse_args(argc, argv);
 262
 263         /* this is copied from the shell script, but it's never triggered... */
 264         if (action == REVERT && !no_replay)
 265                 die("revert is incompatible with replay");
 266
 267         if (no_commit) {
 268                 /*
 269                  * We do not intend to commit immediately.  We just want to
 270                  * merge the differences in, so let's compute the tree
 271                  * that represents the "current" state for merge-recursive
 272                  * to work on.
 273                  */
 274                 if (write_cache_as_tree(head, 0, NULL))
 275                         die ("Your index file is unmerged.");
 276         } else {
 277                 struct wt_status s;
 278
 279                 if (get_sha1("HEAD", head))
 280                         die ("You do not have a valid HEAD");
 281                 wt_status_prepare(&s);
 282                 if (s.commitable)
 283                         die ("Dirty index: cannot %s", me);
 284                 discard_cache();
 285         }
 286
 287         if (!commit->parents)
 288                 die ("Cannot %s a root commit", me);
 289         if (commit->parents->next) {
 290                 /* Reverting or cherry-picking a merge commit */
 291                 int cnt;
 292                 struct commit_list *p;
 293
 294                 if (!mainline)
 295                         die("Commit %s is a merge but no -m option was given.",
 296                             sha1_to_hex(commit->object.sha1));
 297
 298                 for (cnt = 1, p = commit->parents;
 299                      cnt != mainline && p;
 300                      cnt++)
 301                         p = p->next;
 302                 if (cnt != mainline || !p)
 303                         die("Commit %s does not have parent %d",
 304                             sha1_to_hex(commit->object.sha1), mainline);
 305                 parent = p->item;
 306         } else if (0 < mainline)
 307                 die("Mainline was specified but commit %s is not a merge.",
 308                     sha1_to_hex(commit->object.sha1));
 309         else
 310                 parent = commit->parents->item;
 311
 312         if (!(message = commit->buffer))
 313                 die ("Cannot get commit message for %s",
 314                                 sha1_to_hex(commit->object.sha1));
 315
 316         /*
 317          * "commit" is an existing commit.  We would want to apply
 318          * the difference it introduces since its first parent "prev"
 319          * on top of the current HEAD if we are cherry-pick.  Or the
 320          * reverse of it if we are revert.
 321          */
 322
 323         msg_fd = hold_lock_file_for_update(&msg_file, defmsg, 1);
 324
 325         encoding = get_encoding(message);
 326         if (!encoding)
 327                 encoding = "utf-8";
 328         if (!git_commit_encoding)
 329                 git_commit_encoding = "utf-8";
 330         if ((reencoded_message = reencode_string(message,
 331                                         git_commit_encoding, encoding)))
 332                 message = reencoded_message;
 333
 334         oneline = get_oneline(message);
 335
 336         if (action == REVERT) {
 337                 char *oneline_body = strchr(oneline, ' ');
 338
 339                 base = commit;
 340                 next = parent;
 341                 add_to_msg("Revert \"");
 342                 add_to_msg(oneline_body + 1);
 343                 add_to_msg("\"\n\nThis reverts commit ");
 344                 add_to_msg(sha1_to_hex(commit->object.sha1));
 345                 add_to_msg(".\n");
 346         } else {
 347                 base = parent;
 348                 next = commit;
 349                 set_author_ident_env(message);
 350                 add_message_to_msg(message);
 351                 if (no_replay) {
 352                         add_to_msg("(cherry picked from commit ");
 353                         add_to_msg(sha1_to_hex(commit->object.sha1));
 354                         add_to_msg(")\n");
 355                 }
 356         }
 357
 358         if (merge_recursive(sha1_to_hex(base->object.sha1),
 359                                 sha1_to_hex(head), "HEAD",
 360                                 sha1_to_hex(next->object.sha1), oneline) ||
 361                         write_cache_as_tree(head, 0, NULL)) {
 362                 add_to_msg("\nConflicts:\n\n");
 363                 read_cache();
 364                 for (i = 0; i < active_nr;) {
 365                         struct cache_entry *ce = active_cache[i++];
 366                         if (ce_stage(ce)) {
 367                                 add_to_msg("\t");
 368                                 add_to_msg(ce->name);
 369                                 add_to_msg("\n");
 370                                 while (i < active_nr && !strcmp(ce->name,
 371                                                 active_cache[i]->name))
 372                                         i++;
 373                         }
 374                 }
 375                 if (commit_lock_file(&msg_file) < 0)
 376                         die ("Error wrapping up %s", defmsg);
 377                 fprintf(stderr, "Automatic %s failed.%s\n",
 378                         me, help_msg(commit->object.sha1));
 379                 exit(1);
 380         }
 381         if (commit_lock_file(&msg_file) < 0)
 382                 die ("Error wrapping up %s", defmsg);
 383         fprintf(stderr, "Finished one %s.\n", me);
 384
 385         /*
 386          *
 387          * If we are cherry-pick, and if the merge did not result in
 388          * hand-editing, we will hit this commit and inherit the original
 389          * author date and name.
 390          * If we are revert, or if our cherry-pick results in a hand merge,
 391          * we had better say that the current user is responsible for that.
 392          */
 393
 394         if (!no_commit) {
 395                 if (edit)
 396                         return execl_git_cmd("commit", "-n", NULL);
 397                 else
 398                         return execl_git_cmd("commit", "-n", "-F", defmsg, NULL);
 399         }
 400         free(reencoded_message);
 401
 402         return 0;
 403 }
 404
 405 int cmd_revert(int argc, const char **argv, const char *prefix)
 406 {
 407         if (isatty(0))
 408                 edit = 1;
 409         no_replay = 1;
 410         action = REVERT;
 411         return revert_or_cherry_pick(argc, argv);
 412 }
 413
 414 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
 415 {
 416         no_replay = 0;
 417         action = CHERRY_PICK;
 418         return revert_or_cherry_pick(argc, argv);
 419 }