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