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