git.oblomov.eu Git - git/blob - builtin/replace.c

   1 /*
   2  * Builtin "git replace"
   3  *
   4  * Copyright (c) 2008 Christian Couder <chriscool@tuxfamily.org>
   5  *
   6  * Based on builtin/tag.c by Kristian Høgsberg <krh@redhat.com>
   7  * and Carlos Rica <jasampler@gmail.com> that was itself based on
   8  * git-tag.sh and mktag.c by Linus Torvalds.
   9  */
  10
  11 #include "cache.h"
  12 #include "config.h"
  13 #include "builtin.h"
  14 #include "refs.h"
  15 #include "parse-options.h"
  16 #include "run-command.h"
  17 #include "tag.h"
  18
  19 static const char * const git_replace_usage[] = {
  20         N_("git replace [-f] <object> <replacement>"),
  21         N_("git replace [-f] --edit <object>"),
  22         N_("git replace [-f] --graft <commit> [<parent>...]"),
  23         N_("git replace -d <object>..."),
  24         N_("git replace [--format=<format>] [-l [<pattern>]]"),
  25         NULL
  26 };
  27
  28 enum replace_format {
  29         REPLACE_FORMAT_SHORT,
  30         REPLACE_FORMAT_MEDIUM,
  31         REPLACE_FORMAT_LONG
  32 };
  33
  34 struct show_data {
  35         const char *pattern;
  36         enum replace_format format;
  37 };
  38
  39 static int show_reference(const char *refname, const struct object_id *oid,
  40                           int flag, void *cb_data)
  41 {
  42         struct show_data *data = cb_data;
  43
  44         if (!wildmatch(data->pattern, refname, 0)) {
  45                 if (data->format == REPLACE_FORMAT_SHORT)
  46                         printf("%s\n", refname);
  47                 else if (data->format == REPLACE_FORMAT_MEDIUM)
  48                         printf("%s -> %s\n", refname, oid_to_hex(oid));
  49                 else { /* data->format == REPLACE_FORMAT_LONG */
  50                         struct object_id object;
  51                         enum object_type obj_type, repl_type;
  52
  53                         if (get_oid(refname, &object))
  54                                 return error("Failed to resolve '%s' as a valid ref.", refname);
  55
  56                         obj_type = oid_object_info(&object, NULL);
  57                         repl_type = oid_object_info(oid, NULL);
  58
  59                         printf("%s (%s) -> %s (%s)\n", refname, type_name(obj_type),
  60                                oid_to_hex(oid), type_name(repl_type));
  61                 }
  62         }
  63
  64         return 0;
  65 }
  66
  67 static int list_replace_refs(const char *pattern, const char *format)
  68 {
  69         struct show_data data;
  70
  71         if (pattern == NULL)
  72                 pattern = "*";
  73         data.pattern = pattern;
  74
  75         if (format == NULL || *format == '\0' || !strcmp(format, "short"))
  76                 data.format = REPLACE_FORMAT_SHORT;
  77         else if (!strcmp(format, "medium"))
  78                 data.format = REPLACE_FORMAT_MEDIUM;
  79         else if (!strcmp(format, "long"))
  80                 data.format = REPLACE_FORMAT_LONG;
  81         else
  82                 return error("invalid replace format '%s'\n"
  83                              "valid formats are 'short', 'medium' and 'long'\n",
  84                              format);
  85
  86         for_each_replace_ref(show_reference, (void *)&data);
  87
  88         return 0;
  89 }
  90
  91 typedef int (*each_replace_name_fn)(const char *name, const char *ref,
  92                                     const struct object_id *oid);
  93
  94 static int for_each_replace_name(const char **argv, each_replace_name_fn fn)
  95 {
  96         const char **p, *full_hex;
  97         struct strbuf ref = STRBUF_INIT;
  98         size_t base_len;
  99         int had_error = 0;
 100         struct object_id oid;
 101
 102         strbuf_addstr(&ref, git_replace_ref_base);
 103         base_len = ref.len;
 104
 105         for (p = argv; *p; p++) {
 106                 if (get_oid(*p, &oid)) {
 107                         error("Failed to resolve '%s' as a valid ref.", *p);
 108                         had_error = 1;
 109                         continue;
 110                 }
 111
 112                 strbuf_setlen(&ref, base_len);
 113                 strbuf_addstr(&ref, oid_to_hex(&oid));
 114                 full_hex = ref.buf + base_len;
 115
 116                 if (read_ref(ref.buf, &oid)) {
 117                         error("replace ref '%s' not found.", full_hex);
 118                         had_error = 1;
 119                         continue;
 120                 }
 121                 if (fn(full_hex, ref.buf, &oid))
 122                         had_error = 1;
 123         }
 124         strbuf_release(&ref);
 125         return had_error;
 126 }
 127
 128 static int delete_replace_ref(const char *name, const char *ref,
 129                               const struct object_id *oid)
 130 {
 131         if (delete_ref(NULL, ref, oid, 0))
 132                 return 1;
 133         printf("Deleted replace ref '%s'\n", name);
 134         return 0;
 135 }
 136
 137 static int check_ref_valid(struct object_id *object,
 138                             struct object_id *prev,
 139                             struct strbuf *ref,
 140                             int force)
 141 {
 142         strbuf_reset(ref);
 143         strbuf_addf(ref, "%s%s", git_replace_ref_base, oid_to_hex(object));
 144         if (check_refname_format(ref->buf, 0))
 145                 return error("'%s' is not a valid ref name.", ref->buf);
 146
 147         if (read_ref(ref->buf, prev))
 148                 oidclr(prev);
 149         else if (!force)
 150                 return error("replace ref '%s' already exists", ref->buf);
 151         return 0;
 152 }
 153
 154 static int replace_object_oid(const char *object_ref,
 155                                struct object_id *object,
 156                                const char *replace_ref,
 157                                struct object_id *repl,
 158                                int force)
 159 {
 160         struct object_id prev;
 161         enum object_type obj_type, repl_type;
 162         struct strbuf ref = STRBUF_INIT;
 163         struct ref_transaction *transaction;
 164         struct strbuf err = STRBUF_INIT;
 165         int res = 0;
 166
 167         obj_type = oid_object_info(object, NULL);
 168         repl_type = oid_object_info(repl, NULL);
 169         if (!force && obj_type != repl_type)
 170                 return error("Objects must be of the same type.\n"
 171                              "'%s' points to a replaced object of type '%s'\n"
 172                              "while '%s' points to a replacement object of "
 173                              "type '%s'.",
 174                              object_ref, type_name(obj_type),
 175                              replace_ref, type_name(repl_type));
 176
 177         if (check_ref_valid(object, &prev, &ref, force)) {
 178                 strbuf_release(&ref);
 179                 return -1;
 180         }
 181
 182         transaction = ref_transaction_begin(&err);
 183         if (!transaction ||
 184             ref_transaction_update(transaction, ref.buf, repl, &prev,
 185                                    0, NULL, &err) ||
 186             ref_transaction_commit(transaction, &err))
 187                 res = error("%s", err.buf);
 188
 189         ref_transaction_free(transaction);
 190         strbuf_release(&ref);
 191         return res;
 192 }
 193
 194 static int replace_object(const char *object_ref, const char *replace_ref, int force)
 195 {
 196         struct object_id object, repl;
 197
 198         if (get_oid(object_ref, &object))
 199                 return error("Failed to resolve '%s' as a valid ref.",
 200                              object_ref);
 201         if (get_oid(replace_ref, &repl))
 202                 return error("Failed to resolve '%s' as a valid ref.",
 203                              replace_ref);
 204
 205         return replace_object_oid(object_ref, &object, replace_ref, &repl, force);
 206 }
 207
 208 /*
 209  * Write the contents of the object named by "sha1" to the file "filename".
 210  * If "raw" is true, then the object's raw contents are printed according to
 211  * "type". Otherwise, we pretty-print the contents for human editing.
 212  */
 213 static int export_object(const struct object_id *oid, enum object_type type,
 214                           int raw, const char *filename)
 215 {
 216         struct child_process cmd = CHILD_PROCESS_INIT;
 217         int fd;
 218
 219         fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
 220         if (fd < 0)
 221                 return error_errno("unable to open %s for writing", filename);
 222
 223         argv_array_push(&cmd.args, "--no-replace-objects");
 224         argv_array_push(&cmd.args, "cat-file");
 225         if (raw)
 226                 argv_array_push(&cmd.args, type_name(type));
 227         else
 228                 argv_array_push(&cmd.args, "-p");
 229         argv_array_push(&cmd.args, oid_to_hex(oid));
 230         cmd.git_cmd = 1;
 231         cmd.out = fd;
 232
 233         if (run_command(&cmd))
 234                 return error("cat-file reported failure");
 235         return 0;
 236 }
 237
 238 /*
 239  * Read a previously-exported (and possibly edited) object back from "filename",
 240  * interpreting it as "type", and writing the result to the object database.
 241  * The sha1 of the written object is returned via sha1.
 242  */
 243 static int import_object(struct object_id *oid, enum object_type type,
 244                           int raw, const char *filename)
 245 {
 246         int fd;
 247
 248         fd = open(filename, O_RDONLY);
 249         if (fd < 0)
 250                 return error_errno("unable to open %s for reading", filename);
 251
 252         if (!raw && type == OBJ_TREE) {
 253                 const char *argv[] = { "mktree", NULL };
 254                 struct child_process cmd = CHILD_PROCESS_INIT;
 255                 struct strbuf result = STRBUF_INIT;
 256
 257                 cmd.argv = argv;
 258                 cmd.git_cmd = 1;
 259                 cmd.in = fd;
 260                 cmd.out = -1;
 261
 262                 if (start_command(&cmd)) {
 263                         close(fd);
 264                         return error("unable to spawn mktree");
 265                 }
 266
 267                 if (strbuf_read(&result, cmd.out, 41) < 0) {
 268                         error_errno("unable to read from mktree");
 269                         close(fd);
 270                         close(cmd.out);
 271                         return -1;
 272                 }
 273                 close(cmd.out);
 274
 275                 if (finish_command(&cmd)) {
 276                         strbuf_release(&result);
 277                         return error("mktree reported failure");
 278                 }
 279                 if (get_oid_hex(result.buf, oid) < 0) {
 280                         strbuf_release(&result);
 281                         return error("mktree did not return an object name");
 282                 }
 283
 284                 strbuf_release(&result);
 285         } else {
 286                 struct stat st;
 287                 int flags = HASH_FORMAT_CHECK | HASH_WRITE_OBJECT;
 288
 289                 if (fstat(fd, &st) < 0) {
 290                         error_errno("unable to fstat %s", filename);
 291                         close(fd);
 292                         return -1;
 293                 }
 294                 if (index_fd(oid, fd, &st, type, NULL, flags) < 0)
 295                         return error("unable to write object to database");
 296                 /* index_fd close()s fd for us */
 297         }
 298
 299         /*
 300          * No need to close(fd) here; both run-command and index-fd
 301          * will have done it for us.
 302          */
 303         return 0;
 304 }
 305
 306 static int edit_and_replace(const char *object_ref, int force, int raw)
 307 {
 308         char *tmpfile;
 309         enum object_type type;
 310         struct object_id old_oid, new_oid, prev;
 311         struct strbuf ref = STRBUF_INIT;
 312
 313         if (get_oid(object_ref, &old_oid) < 0)
 314                 return error("Not a valid object name: '%s'", object_ref);
 315
 316         type = oid_object_info(&old_oid, NULL);
 317         if (type < 0)
 318                 return error("unable to get object type for %s",
 319                              oid_to_hex(&old_oid));
 320
 321         if (check_ref_valid(&old_oid, &prev, &ref, force)) {
 322                 strbuf_release(&ref);
 323                 return -1;
 324         }
 325         strbuf_release(&ref);
 326
 327         tmpfile = git_pathdup("REPLACE_EDITOBJ");
 328         if (export_object(&old_oid, type, raw, tmpfile)) {
 329                 free(tmpfile);
 330                 return -1;
 331         }
 332         if (launch_editor(tmpfile, NULL, NULL) < 0) {
 333                 free(tmpfile);
 334                 return error("editing object file failed");
 335         }
 336         if (import_object(&new_oid, type, raw, tmpfile)) {
 337                 free(tmpfile);
 338                 return -1;
 339         }
 340         free(tmpfile);
 341
 342         if (!oidcmp(&old_oid, &new_oid))
 343                 return error("new object is the same as the old one: '%s'", oid_to_hex(&old_oid));
 344
 345         return replace_object_oid(object_ref, &old_oid, "replacement", &new_oid, force);
 346 }
 347
 348 static int replace_parents(struct strbuf *buf, int argc, const char **argv)
 349 {
 350         struct strbuf new_parents = STRBUF_INIT;
 351         const char *parent_start, *parent_end;
 352         int i;
 353
 354         /* find existing parents */
 355         parent_start = buf->buf;
 356         parent_start += GIT_SHA1_HEXSZ + 6; /* "tree " + "hex sha1" + "\n" */
 357         parent_end = parent_start;
 358
 359         while (starts_with(parent_end, "parent "))
 360                 parent_end += 48; /* "parent " + "hex sha1" + "\n" */
 361
 362         /* prepare new parents */
 363         for (i = 0; i < argc; i++) {
 364                 struct object_id oid;
 365                 if (get_oid(argv[i], &oid) < 0) {
 366                         strbuf_release(&new_parents);
 367                         return error(_("Not a valid object name: '%s'"),
 368                                      argv[i]);
 369                 }
 370                 if (!lookup_commit_reference(&oid)) {
 371                         strbuf_release(&new_parents);
 372                         return error(_("could not parse %s"), argv[i]);
 373                 }
 374                 strbuf_addf(&new_parents, "parent %s\n", oid_to_hex(&oid));
 375         }
 376
 377         /* replace existing parents with new ones */
 378         strbuf_splice(buf, parent_start - buf->buf, parent_end - parent_start,
 379                       new_parents.buf, new_parents.len);
 380
 381         strbuf_release(&new_parents);
 382         return 0;
 383 }
 384
 385 struct check_mergetag_data {
 386         int argc;
 387         const char **argv;
 388 };
 389
 390 static int check_one_mergetag(struct commit *commit,
 391                                struct commit_extra_header *extra,
 392                                void *data)
 393 {
 394         struct check_mergetag_data *mergetag_data = (struct check_mergetag_data *)data;
 395         const char *ref = mergetag_data->argv[0];
 396         struct object_id tag_oid;
 397         struct tag *tag;
 398         int i;
 399
 400         hash_object_file(extra->value, extra->len, type_name(OBJ_TAG), &tag_oid);
 401         tag = lookup_tag(&tag_oid);
 402         if (!tag)
 403                 return error(_("bad mergetag in commit '%s'"), ref);
 404         if (parse_tag_buffer(tag, extra->value, extra->len))
 405                 return error(_("malformed mergetag in commit '%s'"), ref);
 406
 407         /* iterate over new parents */
 408         for (i = 1; i < mergetag_data->argc; i++) {
 409                 struct object_id oid;
 410                 if (get_oid(mergetag_data->argv[i], &oid) < 0)
 411                         return error(_("Not a valid object name: '%s'"),
 412                                      mergetag_data->argv[i]);
 413                 if (!oidcmp(&tag->tagged->oid, &oid))
 414                         return 0; /* found */
 415         }
 416
 417         return error(_("original commit '%s' contains mergetag '%s' that is "
 418                        "discarded; use --edit instead of --graft"), ref,
 419                      oid_to_hex(&tag_oid));
 420 }
 421
 422 static int check_mergetags(struct commit *commit, int argc, const char **argv)
 423 {
 424         struct check_mergetag_data mergetag_data;
 425
 426         mergetag_data.argc = argc;
 427         mergetag_data.argv = argv;
 428         return for_each_mergetag(check_one_mergetag, commit, &mergetag_data);
 429 }
 430
 431 static int create_graft(int argc, const char **argv, int force)
 432 {
 433         struct object_id old_oid, new_oid;
 434         const char *old_ref = argv[0];
 435         struct commit *commit;
 436         struct strbuf buf = STRBUF_INIT;
 437         const char *buffer;
 438         unsigned long size;
 439
 440         if (get_oid(old_ref, &old_oid) < 0)
 441                 return error(_("Not a valid object name: '%s'"), old_ref);
 442         commit = lookup_commit_reference(&old_oid);
 443         if (!commit)
 444                 return error(_("could not parse %s"), old_ref);
 445
 446         buffer = get_commit_buffer(commit, &size);
 447         strbuf_add(&buf, buffer, size);
 448         unuse_commit_buffer(commit, buffer);
 449
 450         if (replace_parents(&buf, argc - 1, &argv[1]) < 0) {
 451                 strbuf_release(&buf);
 452                 return -1;
 453         }
 454
 455         if (remove_signature(&buf)) {
 456                 warning(_("the original commit '%s' has a gpg signature."), old_ref);
 457                 warning(_("the signature will be removed in the replacement commit!"));
 458         }
 459
 460         if (check_mergetags(commit, argc, argv)) {
 461                 strbuf_release(&buf);
 462                 return -1;
 463         }
 464
 465         if (write_object_file(buf.buf, buf.len, commit_type, &new_oid)) {
 466                 strbuf_release(&buf);
 467                 return error(_("could not write replacement commit for: '%s'"),
 468                              old_ref);
 469         }
 470
 471         strbuf_release(&buf);
 472
 473         if (!oidcmp(&old_oid, &new_oid))
 474                 return error("new commit is the same as the old one: '%s'", oid_to_hex(&old_oid));
 475
 476         return replace_object_oid(old_ref, &old_oid, "replacement", &new_oid, force);
 477 }
 478
 479 int cmd_replace(int argc, const char **argv, const char *prefix)
 480 {
 481         int force = 0;
 482         int raw = 0;
 483         const char *format = NULL;
 484         enum {
 485                 MODE_UNSPECIFIED = 0,
 486                 MODE_LIST,
 487                 MODE_DELETE,
 488                 MODE_EDIT,
 489                 MODE_GRAFT,
 490                 MODE_REPLACE
 491         } cmdmode = MODE_UNSPECIFIED;
 492         struct option options[] = {
 493                 OPT_CMDMODE('l', "list", &cmdmode, N_("list replace refs"), MODE_LIST),
 494                 OPT_CMDMODE('d', "delete", &cmdmode, N_("delete replace refs"), MODE_DELETE),
 495                 OPT_CMDMODE('e', "edit", &cmdmode, N_("edit existing object"), MODE_EDIT),
 496                 OPT_CMDMODE('g', "graft", &cmdmode, N_("change a commit's parents"), MODE_GRAFT),
 497                 OPT_BOOL_F('f', "force", &force, N_("replace the ref if it exists"),
 498                            PARSE_OPT_NOCOMPLETE),
 499                 OPT_BOOL(0, "raw", &raw, N_("do not pretty-print contents for --edit")),
 500                 OPT_STRING(0, "format", &format, N_("format"), N_("use this format")),
 501                 OPT_END()
 502         };
 503
 504         check_replace_refs = 0;
 505         git_config(git_default_config, NULL);
 506
 507         argc = parse_options(argc, argv, prefix, options, git_replace_usage, 0);
 508
 509         if (!cmdmode)
 510                 cmdmode = argc ? MODE_REPLACE : MODE_LIST;
 511
 512         if (format && cmdmode != MODE_LIST)
 513                 usage_msg_opt("--format cannot be used when not listing",
 514                               git_replace_usage, options);
 515
 516         if (force &&
 517             cmdmode != MODE_REPLACE &&
 518             cmdmode != MODE_EDIT &&
 519             cmdmode != MODE_GRAFT)
 520                 usage_msg_opt("-f only makes sense when writing a replacement",
 521                               git_replace_usage, options);
 522
 523         if (raw && cmdmode != MODE_EDIT)
 524                 usage_msg_opt("--raw only makes sense with --edit",
 525                               git_replace_usage, options);
 526
 527         switch (cmdmode) {
 528         case MODE_DELETE:
 529                 if (argc < 1)
 530                         usage_msg_opt("-d needs at least one argument",
 531                                       git_replace_usage, options);
 532                 return for_each_replace_name(argv, delete_replace_ref);
 533
 534         case MODE_REPLACE:
 535                 if (argc != 2)
 536                         usage_msg_opt("bad number of arguments",
 537                                       git_replace_usage, options);
 538                 return replace_object(argv[0], argv[1], force);
 539
 540         case MODE_EDIT:
 541                 if (argc != 1)
 542                         usage_msg_opt("-e needs exactly one argument",
 543                                       git_replace_usage, options);
 544                 return edit_and_replace(argv[0], force, raw);
 545
 546         case MODE_GRAFT:
 547                 if (argc < 1)
 548                         usage_msg_opt("-g needs at least one argument",
 549                                       git_replace_usage, options);
 550                 return create_graft(argc, argv, force);
 551
 552         case MODE_LIST:
 553                 if (argc > 1)
 554                         usage_msg_opt("only one pattern can be given with -l",
 555                                       git_replace_usage, options);
 556                 return list_replace_refs(argv[0], format);
 557
 558         default:
 559                 BUG("invalid cmdmode %d", (int)cmdmode);
 560         }
 561 }