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