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