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