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