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 "builtin.h"
  12 #include "config.h"
  13 #include "editor.h"
  14 #include "environment.h"
  15 #include "gettext.h"
  16 #include "hex.h"
  17 #include "refs.h"
  18 #include "parse-options.h"
  19 #include "path.h"
  20 #include "run-command.h"
  21 #include "object-file.h"
  22 #include "object-name.h"
  23 #include "object-store-ll.h"
  24 #include "replace-object.h"
  25 #include "repository.h"
  26 #include "tag.h"
  27 #include "wildmatch.h"
  28
  29 static const char * const git_replace_usage[] = {
  30         N_("git replace [-f] <object> <replacement>"),
  31         N_("git replace [-f] --edit <object>"),
  32         N_("git replace [-f] --graft <commit> [<parent>...]"),
  33         "git replace [-f] --convert-graft-file",
  34         N_("git replace -d <object>..."),
  35         N_("git replace [--format=<format>] [-l [<pattern>]]"),
  36         NULL
  37 };
  38
  39 enum replace_format {
  40         REPLACE_FORMAT_SHORT,
  41         REPLACE_FORMAT_MEDIUM,
  42         REPLACE_FORMAT_LONG
  43 };
  44
  45 struct show_data {
  46         const char *pattern;
  47         enum replace_format format;
  48 };
  49
  50 static int show_reference(struct repository *r, const char *refname,
  51                           const struct object_id *oid,
  52                           int flag UNUSED, void *cb_data)
  53 {
  54         struct show_data *data = cb_data;
  55
  56         if (!wildmatch(data->pattern, refname, 0)) {
  57                 if (data->format == REPLACE_FORMAT_SHORT)
  58                         printf("%s\n", refname);
  59                 else if (data->format == REPLACE_FORMAT_MEDIUM)
  60                         printf("%s -> %s\n", refname, oid_to_hex(oid));
  61                 else { /* data->format == REPLACE_FORMAT_LONG */
  62                         struct object_id object;
  63                         enum object_type obj_type, repl_type;
  64
  65                         if (repo_get_oid(r, refname, &object))
  66                                 return error(_("failed to resolve '%s' as a valid ref"), refname);
  67
  68                         obj_type = oid_object_info(r, &object, NULL);
  69                         repl_type = oid_object_info(r, oid, NULL);
  70
  71                         printf("%s (%s) -> %s (%s)\n", refname, type_name(obj_type),
  72                                oid_to_hex(oid), type_name(repl_type));
  73                 }
  74         }
  75
  76         return 0;
  77 }
  78
  79 static int list_replace_refs(const char *pattern, const char *format)
  80 {
  81         struct show_data data;
  82
  83         if (!pattern)
  84                 pattern = "*";
  85         data.pattern = pattern;
  86
  87         if (format == NULL || *format == '\0' || !strcmp(format, "short"))
  88                 data.format = REPLACE_FORMAT_SHORT;
  89         else if (!strcmp(format, "medium"))
  90                 data.format = REPLACE_FORMAT_MEDIUM;
  91         else if (!strcmp(format, "long"))
  92                 data.format = REPLACE_FORMAT_LONG;
  93         /*
  94          * Please update _git_replace() in git-completion.bash when
  95          * you add new format
  96          */
  97         else
  98                 return error(_("invalid replace format '%s'\n"
  99                                "valid formats are 'short', 'medium' and 'long'"),
 100                              format);
 101
 102         for_each_replace_ref(the_repository, show_reference, (void *)&data);
 103
 104         return 0;
 105 }
 106
 107 typedef int (*each_replace_name_fn)(const char *name, const char *ref,
 108                                     const struct object_id *oid);
 109
 110 static int for_each_replace_name(const char **argv, each_replace_name_fn fn)
 111 {
 112         const char **p, *full_hex;
 113         struct strbuf ref = STRBUF_INIT;
 114         size_t base_len;
 115         int had_error = 0;
 116         struct object_id oid;
 117         const char *git_replace_ref_base = ref_namespace[NAMESPACE_REPLACE].ref;
 118
 119         strbuf_addstr(&ref, git_replace_ref_base);
 120         base_len = ref.len;
 121
 122         for (p = argv; *p; p++) {
 123                 if (repo_get_oid(the_repository, *p, &oid)) {
 124                         error("failed to resolve '%s' as a valid ref", *p);
 125                         had_error = 1;
 126                         continue;
 127                 }
 128
 129                 strbuf_setlen(&ref, base_len);
 130                 strbuf_addstr(&ref, oid_to_hex(&oid));
 131                 full_hex = ref.buf + base_len;
 132
 133                 if (refs_read_ref(get_main_ref_store(the_repository), ref.buf, &oid)) {
 134                         error(_("replace ref '%s' not found"), full_hex);
 135                         had_error = 1;
 136                         continue;
 137                 }
 138                 if (fn(full_hex, ref.buf, &oid))
 139                         had_error = 1;
 140         }
 141         strbuf_release(&ref);
 142         return had_error;
 143 }
 144
 145 static int delete_replace_ref(const char *name, const char *ref,
 146                               const struct object_id *oid)
 147 {
 148         if (refs_delete_ref(get_main_ref_store(the_repository), NULL, ref, oid, 0))
 149                 return 1;
 150         printf_ln(_("Deleted replace ref '%s'"), name);
 151         return 0;
 152 }
 153
 154 static int check_ref_valid(struct object_id *object,
 155                             struct object_id *prev,
 156                             struct strbuf *ref,
 157                             int force)
 158 {
 159         const char *git_replace_ref_base = ref_namespace[NAMESPACE_REPLACE].ref;
 160
 161         strbuf_reset(ref);
 162         strbuf_addf(ref, "%s%s", git_replace_ref_base, oid_to_hex(object));
 163         if (check_refname_format(ref->buf, 0))
 164                 return error(_("'%s' is not a valid ref name"), ref->buf);
 165
 166         if (refs_read_ref(get_main_ref_store(the_repository), ref->buf, prev))
 167                 oidclr(prev);
 168         else if (!force)
 169                 return error(_("replace ref '%s' already exists"), ref->buf);
 170         return 0;
 171 }
 172
 173 static int replace_object_oid(const char *object_ref,
 174                                struct object_id *object,
 175                                const char *replace_ref,
 176                                struct object_id *repl,
 177                                int force)
 178 {
 179         struct object_id prev;
 180         enum object_type obj_type, repl_type;
 181         struct strbuf ref = STRBUF_INIT;
 182         struct ref_transaction *transaction;
 183         struct strbuf err = STRBUF_INIT;
 184         int res = 0;
 185
 186         obj_type = oid_object_info(the_repository, object, NULL);
 187         repl_type = oid_object_info(the_repository, repl, NULL);
 188         if (!force && obj_type != repl_type)
 189                 return error(_("Objects must be of the same type.\n"
 190                                "'%s' points to a replaced object of type '%s'\n"
 191                                "while '%s' points to a replacement object of "
 192                                "type '%s'."),
 193                              object_ref, type_name(obj_type),
 194                              replace_ref, type_name(repl_type));
 195
 196         if (check_ref_valid(object, &prev, &ref, force)) {
 197                 strbuf_release(&ref);
 198                 return -1;
 199         }
 200
 201         transaction = ref_store_transaction_begin(get_main_ref_store(the_repository),
 202                                                   &err);
 203         if (!transaction ||
 204             ref_transaction_update(transaction, ref.buf, repl, &prev,
 205                                    NULL, NULL, 0, NULL, &err) ||
 206             ref_transaction_commit(transaction, &err))
 207                 res = error("%s", err.buf);
 208
 209         ref_transaction_free(transaction);
 210         strbuf_release(&ref);
 211         return res;
 212 }
 213
 214 static int replace_object(const char *object_ref, const char *replace_ref, int force)
 215 {
 216         struct object_id object, repl;
 217
 218         if (repo_get_oid(the_repository, object_ref, &object))
 219                 return error(_("failed to resolve '%s' as a valid ref"),
 220                              object_ref);
 221         if (repo_get_oid(the_repository, replace_ref, &repl))
 222                 return error(_("failed to resolve '%s' as a valid ref"),
 223                              replace_ref);
 224
 225         return replace_object_oid(object_ref, &object, replace_ref, &repl, force);
 226 }
 227
 228 /*
 229  * Write the contents of the object named by "sha1" to the file "filename".
 230  * If "raw" is true, then the object's raw contents are printed according to
 231  * "type". Otherwise, we pretty-print the contents for human editing.
 232  */
 233 static int export_object(const struct object_id *oid, enum object_type type,
 234                           int raw, const char *filename)
 235 {
 236         struct child_process cmd = CHILD_PROCESS_INIT;
 237         int fd;
 238
 239         fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
 240         if (fd < 0)
 241                 return error_errno(_("unable to open %s for writing"), filename);
 242
 243         strvec_push(&cmd.args, "--no-replace-objects");
 244         strvec_push(&cmd.args, "cat-file");
 245         if (raw)
 246                 strvec_push(&cmd.args, type_name(type));
 247         else
 248                 strvec_push(&cmd.args, "-p");
 249         strvec_push(&cmd.args, oid_to_hex(oid));
 250         cmd.git_cmd = 1;
 251         cmd.out = fd;
 252
 253         if (run_command(&cmd))
 254                 return error(_("cat-file reported failure"));
 255         return 0;
 256 }
 257
 258 /*
 259  * Read a previously-exported (and possibly edited) object back from "filename",
 260  * interpreting it as "type", and writing the result to the object database.
 261  * The sha1 of the written object is returned via sha1.
 262  */
 263 static int import_object(struct object_id *oid, enum object_type type,
 264                           int raw, const char *filename)
 265 {
 266         int fd;
 267
 268         fd = open(filename, O_RDONLY);
 269         if (fd < 0)
 270                 return error_errno(_("unable to open %s for reading"), filename);
 271
 272         if (!raw && type == OBJ_TREE) {
 273                 struct child_process cmd = CHILD_PROCESS_INIT;
 274                 struct strbuf result = STRBUF_INIT;
 275
 276                 strvec_push(&cmd.args, "mktree");
 277                 cmd.git_cmd = 1;
 278                 cmd.in = fd;
 279                 cmd.out = -1;
 280
 281                 if (start_command(&cmd)) {
 282                         close(fd);
 283                         return error(_("unable to spawn mktree"));
 284                 }
 285
 286                 if (strbuf_read(&result, cmd.out, the_hash_algo->hexsz + 1) < 0) {
 287                         error_errno(_("unable to read from mktree"));
 288                         close(fd);
 289                         close(cmd.out);
 290                         return -1;
 291                 }
 292                 close(cmd.out);
 293
 294                 if (finish_command(&cmd)) {
 295                         strbuf_release(&result);
 296                         return error(_("mktree reported failure"));
 297                 }
 298                 if (get_oid_hex(result.buf, oid) < 0) {
 299                         strbuf_release(&result);
 300                         return error(_("mktree did not return an object name"));
 301                 }
 302
 303                 strbuf_release(&result);
 304         } else {
 305                 struct stat st;
 306                 int flags = HASH_FORMAT_CHECK | HASH_WRITE_OBJECT;
 307
 308                 if (fstat(fd, &st) < 0) {
 309                         error_errno(_("unable to fstat %s"), filename);
 310                         close(fd);
 311                         return -1;
 312                 }
 313                 if (index_fd(the_repository->index, oid, fd, &st, type, NULL, flags) < 0)
 314                         return error(_("unable to write object to database"));
 315                 /* index_fd close()s fd for us */
 316         }
 317
 318         /*
 319          * No need to close(fd) here; both run-command and index-fd
 320          * will have done it for us.
 321          */
 322         return 0;
 323 }
 324
 325 static int edit_and_replace(const char *object_ref, int force, int raw)
 326 {
 327         char *tmpfile;
 328         enum object_type type;
 329         struct object_id old_oid, new_oid, prev;
 330         struct strbuf ref = STRBUF_INIT;
 331
 332         if (repo_get_oid(the_repository, object_ref, &old_oid) < 0)
 333                 return error(_("not a valid object name: '%s'"), object_ref);
 334
 335         type = oid_object_info(the_repository, &old_oid, NULL);
 336         if (type < 0)
 337                 return error(_("unable to get object type for %s"),
 338                              oid_to_hex(&old_oid));
 339
 340         if (check_ref_valid(&old_oid, &prev, &ref, force)) {
 341                 strbuf_release(&ref);
 342                 return -1;
 343         }
 344         strbuf_release(&ref);
 345
 346         tmpfile = git_pathdup("REPLACE_EDITOBJ");
 347         if (export_object(&old_oid, type, raw, tmpfile)) {
 348                 free(tmpfile);
 349                 return -1;
 350         }
 351         if (launch_editor(tmpfile, NULL, NULL) < 0) {
 352                 free(tmpfile);
 353                 return error(_("editing object file failed"));
 354         }
 355         if (import_object(&new_oid, type, raw, tmpfile)) {
 356                 free(tmpfile);
 357                 return -1;
 358         }
 359         free(tmpfile);
 360
 361         if (oideq(&old_oid, &new_oid))
 362                 return error(_("new object is the same as the old one: '%s'"), oid_to_hex(&old_oid));
 363
 364         return replace_object_oid(object_ref, &old_oid, "replacement", &new_oid, force);
 365 }
 366
 367 static int replace_parents(struct strbuf *buf, int argc, const char **argv)
 368 {
 369         struct strbuf new_parents = STRBUF_INIT;
 370         const char *parent_start, *parent_end;
 371         int i;
 372         const unsigned hexsz = the_hash_algo->hexsz;
 373
 374         /* find existing parents */
 375         parent_start = buf->buf;
 376         parent_start += hexsz + 6; /* "tree " + "hex sha1" + "\n" */
 377         parent_end = parent_start;
 378
 379         while (starts_with(parent_end, "parent "))
 380                 parent_end += hexsz + 8; /* "parent " + "hex sha1" + "\n" */
 381
 382         /* prepare new parents */
 383         for (i = 0; i < argc; i++) {
 384                 struct object_id oid;
 385                 struct commit *commit;
 386
 387                 if (repo_get_oid(the_repository, argv[i], &oid) < 0) {
 388                         strbuf_release(&new_parents);
 389                         return error(_("not a valid object name: '%s'"),
 390                                      argv[i]);
 391                 }
 392                 commit = lookup_commit_reference(the_repository, &oid);
 393                 if (!commit) {
 394                         strbuf_release(&new_parents);
 395                         return error(_("could not parse %s as a commit"), argv[i]);
 396                 }
 397                 strbuf_addf(&new_parents, "parent %s\n", oid_to_hex(&commit->object.oid));
 398         }
 399
 400         /* replace existing parents with new ones */
 401         strbuf_splice(buf, parent_start - buf->buf, parent_end - parent_start,
 402                       new_parents.buf, new_parents.len);
 403
 404         strbuf_release(&new_parents);
 405         return 0;
 406 }
 407
 408 struct check_mergetag_data {
 409         int argc;
 410         const char **argv;
 411 };
 412
 413 static int check_one_mergetag(struct commit *commit UNUSED,
 414                                struct commit_extra_header *extra,
 415                                void *data)
 416 {
 417         struct check_mergetag_data *mergetag_data = (struct check_mergetag_data *)data;
 418         const char *ref = mergetag_data->argv[0];
 419         struct object_id tag_oid;
 420         struct tag *tag;
 421         int i;
 422
 423         hash_object_file(the_hash_algo, extra->value, extra->len,
 424                          OBJ_TAG, &tag_oid);
 425         tag = lookup_tag(the_repository, &tag_oid);
 426         if (!tag)
 427                 return error(_("bad mergetag in commit '%s'"), ref);
 428         if (parse_tag_buffer(the_repository, tag, extra->value, extra->len))
 429                 return error(_("malformed mergetag in commit '%s'"), ref);
 430
 431         /* iterate over new parents */
 432         for (i = 1; i < mergetag_data->argc; i++) {
 433                 struct object_id oid;
 434                 if (repo_get_oid(the_repository, mergetag_data->argv[i], &oid) < 0)
 435                         return error(_("not a valid object name: '%s'"),
 436                                      mergetag_data->argv[i]);
 437                 if (oideq(get_tagged_oid(tag), &oid))
 438                         return 0; /* found */
 439         }
 440
 441         return error(_("original commit '%s' contains mergetag '%s' that is "
 442                        "discarded; use --edit instead of --graft"), ref,
 443                      oid_to_hex(&tag_oid));
 444 }
 445
 446 static int check_mergetags(struct commit *commit, int argc, const char **argv)
 447 {
 448         struct check_mergetag_data mergetag_data;
 449
 450         mergetag_data.argc = argc;
 451         mergetag_data.argv = argv;
 452         return for_each_mergetag(check_one_mergetag, commit, &mergetag_data);
 453 }
 454
 455 static int create_graft(int argc, const char **argv, int force, int gentle)
 456 {
 457         struct object_id old_oid, new_oid;
 458         const char *old_ref = argv[0];
 459         struct commit *commit;
 460         struct strbuf buf = STRBUF_INIT;
 461         const char *buffer;
 462         unsigned long size;
 463
 464         if (repo_get_oid(the_repository, old_ref, &old_oid) < 0)
 465                 return error(_("not a valid object name: '%s'"), old_ref);
 466         commit = lookup_commit_reference(the_repository, &old_oid);
 467         if (!commit)
 468                 return error(_("could not parse %s"), old_ref);
 469
 470         buffer = repo_get_commit_buffer(the_repository, commit, &size);
 471         strbuf_add(&buf, buffer, size);
 472         repo_unuse_commit_buffer(the_repository, commit, buffer);
 473
 474         if (replace_parents(&buf, argc - 1, &argv[1]) < 0) {
 475                 strbuf_release(&buf);
 476                 return -1;
 477         }
 478
 479         if (remove_signature(&buf)) {
 480                 warning(_("the original commit '%s' has a gpg signature"), old_ref);
 481                 warning(_("the signature will be removed in the replacement commit!"));
 482         }
 483
 484         if (check_mergetags(commit, argc, argv)) {
 485                 strbuf_release(&buf);
 486                 return -1;
 487         }
 488
 489         if (write_object_file(buf.buf, buf.len, OBJ_COMMIT, &new_oid)) {
 490                 strbuf_release(&buf);
 491                 return error(_("could not write replacement commit for: '%s'"),
 492                              old_ref);
 493         }
 494
 495         strbuf_release(&buf);
 496
 497         if (oideq(&commit->object.oid, &new_oid)) {
 498                 if (gentle) {
 499                         warning(_("graft for '%s' unnecessary"),
 500                                 oid_to_hex(&commit->object.oid));
 501                         return 0;
 502                 }
 503                 return error(_("new commit is the same as the old one: '%s'"),
 504                              oid_to_hex(&commit->object.oid));
 505         }
 506
 507         return replace_object_oid(old_ref, &commit->object.oid,
 508                                   "replacement", &new_oid, force);
 509 }
 510
 511 static int convert_graft_file(int force)
 512 {
 513         const char *graft_file = get_graft_file(the_repository);
 514         FILE *fp = fopen_or_warn(graft_file, "r");
 515         struct strbuf buf = STRBUF_INIT, err = STRBUF_INIT;
 516         struct strvec args = STRVEC_INIT;
 517
 518         if (!fp)
 519                 return -1;
 520
 521         no_graft_file_deprecated_advice = 1;
 522         while (strbuf_getline(&buf, fp) != EOF) {
 523                 if (*buf.buf == '#')
 524                         continue;
 525
 526                 strvec_split(&args, buf.buf);
 527                 if (args.nr && create_graft(args.nr, args.v, force, 1))
 528                         strbuf_addf(&err, "\n\t%s", buf.buf);
 529                 strvec_clear(&args);
 530         }
 531         fclose(fp);
 532
 533         strbuf_release(&buf);
 534
 535         if (!err.len)
 536                 return unlink_or_warn(graft_file);
 537
 538         warning(_("could not convert the following graft(s):\n%s"), err.buf);
 539         strbuf_release(&err);
 540
 541         return -1;
 542 }
 543
 544 int cmd_replace(int argc, const char **argv, const char *prefix)
 545 {
 546         int force = 0;
 547         int raw = 0;
 548         const char *format = NULL;
 549         enum {
 550                 MODE_UNSPECIFIED = 0,
 551                 MODE_LIST,
 552                 MODE_DELETE,
 553                 MODE_EDIT,
 554                 MODE_GRAFT,
 555                 MODE_CONVERT_GRAFT_FILE,
 556                 MODE_REPLACE
 557         } cmdmode = MODE_UNSPECIFIED;
 558         struct option options[] = {
 559                 OPT_CMDMODE('l', "list", &cmdmode, N_("list replace refs"), MODE_LIST),
 560                 OPT_CMDMODE('d', "delete", &cmdmode, N_("delete replace refs"), MODE_DELETE),
 561                 OPT_CMDMODE('e', "edit", &cmdmode, N_("edit existing object"), MODE_EDIT),
 562                 OPT_CMDMODE('g', "graft", &cmdmode, N_("change a commit's parents"), MODE_GRAFT),
 563                 OPT_CMDMODE(0, "convert-graft-file", &cmdmode, N_("convert existing graft file"), MODE_CONVERT_GRAFT_FILE),
 564                 OPT_BOOL_F('f', "force", &force, N_("replace the ref if it exists"),
 565                            PARSE_OPT_NOCOMPLETE),
 566                 OPT_BOOL(0, "raw", &raw, N_("do not pretty-print contents for --edit")),
 567                 OPT_STRING(0, "format", &format, N_("format"), N_("use this format")),
 568                 OPT_END()
 569         };
 570
 571         disable_replace_refs();
 572         git_config(git_default_config, NULL);
 573
 574         argc = parse_options(argc, argv, prefix, options, git_replace_usage, 0);
 575
 576         if (!cmdmode)
 577                 cmdmode = argc ? MODE_REPLACE : MODE_LIST;
 578
 579         if (format && cmdmode != MODE_LIST)
 580                 usage_msg_opt(_("--format cannot be used when not listing"),
 581                               git_replace_usage, options);
 582
 583         if (force &&
 584             cmdmode != MODE_REPLACE &&
 585             cmdmode != MODE_EDIT &&
 586             cmdmode != MODE_GRAFT &&
 587             cmdmode != MODE_CONVERT_GRAFT_FILE)
 588                 usage_msg_opt(_("-f only makes sense when writing a replacement"),
 589                               git_replace_usage, options);
 590
 591         if (raw && cmdmode != MODE_EDIT)
 592                 usage_msg_opt(_("--raw only makes sense with --edit"),
 593                               git_replace_usage, options);
 594
 595         switch (cmdmode) {
 596         case MODE_DELETE:
 597                 if (argc < 1)
 598                         usage_msg_opt(_("-d needs at least one argument"),
 599                                       git_replace_usage, options);
 600                 return for_each_replace_name(argv, delete_replace_ref);
 601
 602         case MODE_REPLACE:
 603                 if (argc != 2)
 604                         usage_msg_opt(_("bad number of arguments"),
 605                                       git_replace_usage, options);
 606                 return replace_object(argv[0], argv[1], force);
 607
 608         case MODE_EDIT:
 609                 if (argc != 1)
 610                         usage_msg_opt(_("-e needs exactly one argument"),
 611                                       git_replace_usage, options);
 612                 return edit_and_replace(argv[0], force, raw);
 613
 614         case MODE_GRAFT:
 615                 if (argc < 1)
 616                         usage_msg_opt(_("-g needs at least one argument"),
 617                                       git_replace_usage, options);
 618                 return create_graft(argc, argv, force, 0);
 619
 620         case MODE_CONVERT_GRAFT_FILE:
 621                 if (argc != 0)
 622                         usage_msg_opt(_("--convert-graft-file takes no argument"),
 623                                       git_replace_usage, options);
 624                 return !!convert_graft_file(force);
 625
 626         case MODE_LIST:
 627                 if (argc > 1)
 628                         usage_msg_opt(_("only one pattern can be given with -l"),
 629                                       git_replace_usage, options);
 630                 return list_replace_refs(argv[0], format);
 631
 632         default:
 633                 BUG("invalid cmdmode %d", (int)cmdmode);
 634         }
 635 }