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
  11 /*
  12  * This implements the builtins revert and cherry-pick.
  13  *
  14  * Copyright (c) 2007 Johannes E. Schindelin
  15  *
  16  * Based on git-revert.sh, which is
  17  *
  18  * Copyright (c) 2005 Linus Torvalds
  19  * Copyright (c) 2005 Junio C Hamano
  20  */
  21
  22 static const char *revert_usage = "git-revert [--edit | --no-edit] [-n] <commit-ish>";
  23
  24 static const char *cherry_pick_usage = "git-cherry-pick [--edit] [-n] [-r] [-x] <commit-ish>";
  25
  26 static int edit;
  27 static int replay;
  28 static enum { REVERT, CHERRY_PICK } action;
  29 static int no_commit;
  30 static struct commit *commit;
  31 static int needed_deref;
  32
  33 static const char *me;
  34
  35 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
  36
  37 static void parse_options(int argc, const char **argv)
  38 {
  39         const char *usage_str = action == REVERT ?
  40                 revert_usage : cherry_pick_usage;
  41         unsigned char sha1[20];
  42         const char *arg;
  43         int i;
  44
  45         if (argc < 2)
  46                 usage(usage_str);
  47
  48         for (i = 1; i < argc; i++) {
  49                 arg = argv[i];
  50                 if (arg[0] != '-')
  51                         break;
  52                 if (!strcmp(arg, "-n") || !strcmp(arg, "--no-commit"))
  53                         no_commit = 1;
  54                 else if (!strcmp(arg, "-e") || !strcmp(arg, "--edit"))
  55                         edit = 1;
  56                 else if (!strcmp(arg, "--no-edit"))
  57                         edit = 0;
  58                 else if (!strcmp(arg, "-x") || !strcmp(arg, "--i-really-want-"
  59                                 "to-expose-my-private-commit-object-name"))
  60                         replay = 0;
  61                 else if (strcmp(arg, "-r"))
  62                         usage(usage_str);
  63         }
  64         if (i != argc - 1)
  65                 usage(usage_str);
  66         arg = argv[argc - 1];
  67         if (get_sha1(arg, sha1))
  68                 die ("Cannot find '%s'", arg);
  69         commit = (struct commit *)parse_object(sha1);
  70         if (!commit)
  71                 die ("Could not find %s", sha1_to_hex(sha1));
  72         if (commit->object.type == OBJ_TAG) {
  73                 commit = (struct commit *)
  74                         deref_tag((struct object *)commit, arg, strlen(arg));
  75                 needed_deref = 1;
  76         }
  77         if (commit->object.type != OBJ_COMMIT)
  78                 die ("'%s' does not point to a commit", arg);
  79 }
  80
  81 static char *get_oneline(const char *message)
  82 {
  83         char *result;
  84         const char *p = message, *abbrev, *eol;
  85         int abbrev_len, oneline_len;
  86
  87         if (!p)
  88                 die ("Could not read commit message of %s",
  89                                 sha1_to_hex(commit->object.sha1));
  90         while (*p && (*p != '\n' || p[1] != '\n'))
  91                 p++;
  92
  93         if (*p) {
  94                 p += 2;
  95                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
  96                         ; /* do nothing */
  97         } else
  98                 eol = p;
  99         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
 100         abbrev_len = strlen(abbrev);
 101         oneline_len = eol - p;
 102         result = xmalloc(abbrev_len + 5 + oneline_len);
 103         memcpy(result, abbrev, abbrev_len);
 104         memcpy(result + abbrev_len, "... ", 4);
 105         memcpy(result + abbrev_len + 4, p, oneline_len);
 106         result[abbrev_len + 4 + oneline_len] = '\0';
 107         return result;
 108 }
 109
 110 static char *get_encoding(const char *message)
 111 {
 112         const char *p = message, *eol;
 113
 114         if (!p)
 115                 die ("Could not read commit message of %s",
 116                                 sha1_to_hex(commit->object.sha1));
 117         while (*p && *p != '\n') {
 118                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
 119                         ; /* do nothing */
 120                 if (!prefixcmp(p, "encoding ")) {
 121                         char *result = xmalloc(eol - 8 - p);
 122                         strlcpy(result, p + 9, eol - 8 - p);
 123                         return result;
 124                 }
 125                 p = eol;
 126                 if (*p == '\n')
 127                         p++;
 128         }
 129         return NULL;
 130 }
 131
 132 static struct lock_file msg_file;
 133 static int msg_fd;
 134
 135 static void add_to_msg(const char *string)
 136 {
 137         int len = strlen(string);
 138         if (write_in_full(msg_fd, string, len) < 0)
 139                 die ("Could not write to MERGE_MSG");
 140 }
 141
 142 static void add_message_to_msg(const char *message)
 143 {
 144         const char *p = message;
 145         while (*p && (*p != '\n' || p[1] != '\n'))
 146                 p++;
 147
 148         if (!*p)
 149                 add_to_msg(sha1_to_hex(commit->object.sha1));
 150
 151         p += 2;
 152         add_to_msg(p);
 153         return;
 154 }
 155
 156 static void set_author_ident_env(const char *message)
 157 {
 158         const char *p = message;
 159         if (!p)
 160                 die ("Could not read commit message of %s",
 161                                 sha1_to_hex(commit->object.sha1));
 162         while (*p && *p != '\n') {
 163                 const char *eol;
 164
 165                 for (eol = p; *eol && *eol != '\n'; eol++)
 166                         ; /* do nothing */
 167                 if (!prefixcmp(p, "author ")) {
 168                         char *line, *pend, *email, *timestamp;
 169
 170                         p += 7;
 171                         line = xmemdupz(p, eol - p);
 172                         email = strchr(line, '<');
 173                         if (!email)
 174                                 die ("Could not extract author email from %s",
 175                                         sha1_to_hex(commit->object.sha1));
 176                         if (email == line)
 177                                 pend = line;
 178                         else
 179                                 for (pend = email; pend != line + 1 &&
 180                                                 isspace(pend[-1]); pend--);
 181                                         ; /* do nothing */
 182                         *pend = '\0';
 183                         email++;
 184                         timestamp = strchr(email, '>');
 185                         if (!timestamp)
 186                                 die ("Could not extract author email from %s",
 187                                         sha1_to_hex(commit->object.sha1));
 188                         *timestamp = '\0';
 189                         for (timestamp++; *timestamp && isspace(*timestamp);
 190                                         timestamp++)
 191                                 ; /* do nothing */
 192                         setenv("GIT_AUTHOR_NAME", line, 1);
 193                         setenv("GIT_AUTHOR_EMAIL", email, 1);
 194                         setenv("GIT_AUTHOR_DATE", timestamp, 1);
 195                         free(line);
 196                         return;
 197                 }
 198                 p = eol;
 199                 if (*p == '\n')
 200                         p++;
 201         }
 202         die ("No author information found in %s",
 203                         sha1_to_hex(commit->object.sha1));
 204 }
 205
 206 static int merge_recursive(const char *base_sha1,
 207                 const char *head_sha1, const char *head_name,
 208                 const char *next_sha1, const char *next_name)
 209 {
 210         char buffer[256];
 211         const char *argv[6];
 212
 213         sprintf(buffer, "GITHEAD_%s", head_sha1);
 214         setenv(buffer, head_name, 1);
 215         sprintf(buffer, "GITHEAD_%s", next_sha1);
 216         setenv(buffer, next_name, 1);
 217
 218         /*
 219          * This three way merge is an interesting one.  We are at
 220          * $head, and would want to apply the change between $commit
 221          * and $prev on top of us (when reverting), or the change between
 222          * $prev and $commit on top of us (when cherry-picking or replaying).
 223          */
 224         argv[0] = "merge-recursive";
 225         argv[1] = base_sha1;
 226         argv[2] = "--";
 227         argv[3] = head_sha1;
 228         argv[4] = next_sha1;
 229         argv[5] = NULL;
 230
 231         return run_command_v_opt(argv, RUN_COMMAND_NO_STDIN | RUN_GIT_CMD);
 232 }
 233
 234 static int revert_or_cherry_pick(int argc, const char **argv)
 235 {
 236         unsigned char head[20];
 237         struct commit *base, *next;
 238         int i;
 239         char *oneline, *reencoded_message = NULL;
 240         const char *message, *encoding;
 241         const char *defmsg = xstrdup(git_path("MERGE_MSG"));
 242
 243         git_config(git_default_config);
 244         me = action == REVERT ? "revert" : "cherry-pick";
 245         setenv(GIT_REFLOG_ACTION, me, 0);
 246         parse_options(argc, argv);
 247
 248         /* this is copied from the shell script, but it's never triggered... */
 249         if (action == REVERT && replay)
 250                 die("revert is incompatible with replay");
 251
 252         if (no_commit) {
 253                 /*
 254                  * We do not intend to commit immediately.  We just want to
 255                  * merge the differences in.
 256                  */
 257                 if (write_tree(head, 0, NULL))
 258                         die ("Your index file is unmerged.");
 259         } else {
 260                 struct wt_status s;
 261
 262                 if (get_sha1("HEAD", head))
 263                         die ("You do not have a valid HEAD");
 264                 wt_status_prepare(&s);
 265                 if (s.commitable || s.workdir_dirty)
 266                         die ("Dirty index: cannot %s", me);
 267                 discard_cache();
 268         }
 269
 270         if (!commit->parents)
 271                 die ("Cannot %s a root commit", me);
 272         if (commit->parents->next)
 273                 die ("Cannot %s a multi-parent commit.", me);
 274         if (!(message = commit->buffer))
 275                 die ("Cannot get commit message for %s",
 276                                 sha1_to_hex(commit->object.sha1));
 277
 278         /*
 279          * "commit" is an existing commit.  We would want to apply
 280          * the difference it introduces since its first parent "prev"
 281          * on top of the current HEAD if we are cherry-pick.  Or the
 282          * reverse of it if we are revert.
 283          */
 284
 285         msg_fd = hold_lock_file_for_update(&msg_file, defmsg, 1);
 286
 287         encoding = get_encoding(message);
 288         if (!encoding)
 289                 encoding = "utf-8";
 290         if (!git_commit_encoding)
 291                 git_commit_encoding = "utf-8";
 292         if ((reencoded_message = reencode_string(message,
 293                                         git_commit_encoding, encoding)))
 294                 message = reencoded_message;
 295
 296         oneline = get_oneline(message);
 297
 298         if (action == REVERT) {
 299                 char *oneline_body = strchr(oneline, ' ');
 300
 301                 base = commit;
 302                 next = commit->parents->item;
 303                 add_to_msg("Revert \"");
 304                 add_to_msg(oneline_body + 1);
 305                 add_to_msg("\"\n\nThis reverts commit ");
 306                 add_to_msg(sha1_to_hex(commit->object.sha1));
 307                 add_to_msg(".\n");
 308         } else {
 309                 base = commit->parents->item;
 310                 next = commit;
 311                 set_author_ident_env(message);
 312                 add_message_to_msg(message);
 313                 if (!replay) {
 314                         add_to_msg("(cherry picked from commit ");
 315                         add_to_msg(sha1_to_hex(commit->object.sha1));
 316                         add_to_msg(")\n");
 317                 }
 318         }
 319         if (needed_deref) {
 320                 add_to_msg("(original 'git ");
 321                 add_to_msg(me);
 322                 add_to_msg("' arguments: ");
 323                 for (i = 0; i < argc; i++) {
 324                         if (i)
 325                                 add_to_msg(" ");
 326                         add_to_msg(argv[i]);
 327                 }
 328                 add_to_msg(")\n");
 329         }
 330
 331         if (merge_recursive(sha1_to_hex(base->object.sha1),
 332                                 sha1_to_hex(head), "HEAD",
 333                                 sha1_to_hex(next->object.sha1), oneline) ||
 334                         write_tree(head, 0, NULL)) {
 335                 add_to_msg("\nConflicts:\n\n");
 336                 read_cache();
 337                 for (i = 0; i < active_nr;) {
 338                         struct cache_entry *ce = active_cache[i++];
 339                         if (ce_stage(ce)) {
 340                                 add_to_msg("\t");
 341                                 add_to_msg(ce->name);
 342                                 add_to_msg("\n");
 343                                 while (i < active_nr && !strcmp(ce->name,
 344                                                 active_cache[i]->name))
 345                                         i++;
 346                         }
 347                 }
 348                 if (close(msg_fd) || commit_lock_file(&msg_file) < 0)
 349                         die ("Error wrapping up %s", defmsg);
 350                 fprintf(stderr, "Automatic %s failed.  "
 351                         "After resolving the conflicts,\n"
 352                         "mark the corrected paths with 'git-add <paths>'\n"
 353                         "and commit the result.\n", me);
 354                 if (action == CHERRY_PICK) {
 355                         fprintf(stderr, "When commiting, use the option "
 356                                 "'-c %s' to retain authorship and message.\n",
 357                                 find_unique_abbrev(commit->object.sha1,
 358                                         DEFAULT_ABBREV));
 359                 }
 360                 exit(1);
 361         }
 362         if (close(msg_fd) || commit_lock_file(&msg_file) < 0)
 363                 die ("Error wrapping up %s", defmsg);
 364         fprintf(stderr, "Finished one %s.\n", me);
 365
 366         /*
 367          *
 368          * If we are cherry-pick, and if the merge did not result in
 369          * hand-editing, we will hit this commit and inherit the original
 370          * author date and name.
 371          * If we are revert, or if our cherry-pick results in a hand merge,
 372          * we had better say that the current user is responsible for that.
 373          */
 374
 375         if (!no_commit) {
 376                 if (edit)
 377                         return execl_git_cmd("commit", "-n", NULL);
 378                 else
 379                         return execl_git_cmd("commit", "-n", "-F", defmsg, NULL);
 380         }
 381         if (reencoded_message)
 382                 free(reencoded_message);
 383
 384         return 0;
 385 }
 386
 387 int cmd_revert(int argc, const char **argv, const char *prefix)
 388 {
 389         if (isatty(0))
 390                 edit = 1;
 391         action = REVERT;
 392         return revert_or_cherry_pick(argc, argv);
 393 }
 394
 395 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
 396 {
 397         replay = 1;
 398         action = CHERRY_PICK;
 399         return revert_or_cherry_pick(argc, argv);
 400 }