builtin/replace.c

   1 /*
   2  * Builtin "git replace"
   3  *
   4  * Copyright (c) 2008 Christian Couder <chriscool@tuxfamily.org>
   5  *
   6  * Based on builtin/tag.c by Kristian Høgsberg <krh@redhat.com>
   7  * and Carlos Rica <jasampler@gmail.com> that was itself based on
   8  * git-tag.sh and mktag.c by Linus Torvalds.
   9  */
  10
  11 #include "builtin.h"
  12 #include "config.h"
  13 #include "editor.h"
  14 #include "environment.h"
  15 #include "gettext.h"
  16 #include "hex.h"
  17 #include "refs.h"
  18 #include "parse-options.h"
  19 #include "path.h"
  20 #include "run-command.h"
  21 #include "object-file.h"
  22 #include "object-name.h"
  23 #include "object-store-ll.h"
  24 #include "replace-object.h"
  25 #include "repository.h"
  26 #include "tag.h"
  27 #include "wildmatch.h"
  28
  29 static const char * const git_replace_usage[] = {
  30         N_("git replace [-f] <object> <replacement>"),
  31         N_("git replace [-f] --edit <object>"),
  32         N_("git replace [-f] --graft <commit> [<parent>...]"),
  33         "git replace [-f] --convert-graft-file",
  34         N_("git replace -d <object>..."),
  35         N_("git replace [--format=<format>] [-l [<pattern>]]"),
  36         NULL
  37 };
  38
  39 enum replace_format {
  40         REPLACE_FORMAT_SHORT,
  41         REPLACE_FORMAT_MEDIUM,
  42         REPLACE_FORMAT_LONG
  43 };
  44
  45 struct show_data {
  46         const char *pattern;
  47         enum replace_format format;
  48 };
  49
  50 static int show_reference(struct repository *r, const char *refname,
  51                           const struct object_id *oid,
  52                           int flag UNUSED, void *cb_data)
  53 {
  54         struct show_data *data = cb_data;
  55
  56         if (!wildmatch(data->pattern, refname, 0)) {
  57                 if (data->format == REPLACE_FORMAT_SHORT)
  58                         printf("%s\n", refname);
  59                 else if (data->format == REPLACE_FORMAT_MEDIUM)
  60                         printf("%s -> %s\n", refname, oid_to_hex(oid));
  61                 else { /* data->format == REPLACE_FORMAT_LONG */
  62                         struct object_id object;
  63                         enum object_type obj_type, repl_type;
  64
  65                         if (repo_get_oid(r, refname, &object))
  66                                 return error(_("failed to resolve '%s' as a valid ref"), refname);
  67
  68                         obj_type = oid_object_info(r, &object, NULL);
  69                         repl_type = oid_object_info(r, oid, NULL);
  70
  71                         printf("%s (%s) -> %s (%s)\n", refname, type_name(obj_type),
  72                                oid_to_hex(oid), type_name(repl_type));
  73                 }
  74         }
  75
  76         return 0;
  77 }
  78
  79 static int list_replace_refs(const char *pattern, const char *format)
  80 {
  81         struct show_data data;
  82
  83         if (!pattern)
  84                 pattern = "*";
  85         data.pattern = pattern;
  86
  87         if (format == NULL || *format == '\0' || !strcmp(format, "short"))
  88                 data.format = REPLACE_FORMAT_SHORT;
  89         else if (!strcmp(format, "medium"))
  90                 data.format = REPLACE_FORMAT_MEDIUM;
  91         else if (!strcmp(format, "long"))
  92                 data.format = REPLACE_FORMAT_LONG;
  93         /*
  94          * Please update _git_replace() in git-completion.bash when
  95          * you add new format
  96          */
  97         else
  98                 return error(_("invalid replace format '%s'\n"
  99                                "valid formats are 'short', 'medium' and 'long'"),
 100                              format);
 101
 102         for_each_replace_ref(the_repository, show_reference, (void *)&data);
 103
 104         return 0;
 105 }
 106
 107 typedef int (*each_replace_name_fn)(const char *name, const char *ref,
 108                                     const struct object_id *oid);
 109
 110 static int for_each_replace_name(const char **argv, each_replace_name_fn fn)
 111 {
 112         const char **p, *full_hex;
 113         struct strbuf ref = STRBUF_INIT;
 114         size_t base_len;
 115         int had_error = 0;
 116         struct object_id oid;
 117         const char *git_replace_ref_base = ref_namespace[NAMESPACE_REPLACE].ref;
 118
 119         strbuf_addstr(&ref, git_replace_ref_base);
 120         base_len = ref.len;
 121
 122         for (p = argv; *p; p++) {
 123                 if (repo_get_oid(the_repository, *p, &oid)) {
 124                         error("failed to resolve '%s' as a valid ref", *p);
 125                         had_error = 1;
 126                         continue;
 127                 }
 128
 129                 strbuf_setlen(&ref, base_len);
 130                 strbuf_addstr(&ref, oid_to_hex(&oid));
 131                 full_hex = ref.buf + base_len;
 132
 133                 if (read_ref(ref.buf, &oid)) {
 134                         error(_("replace ref '%s' not found"), full_hex);
 135                         had_error = 1;
 136                         continue;
 137                 }
 138                 if (fn(full_hex, ref.buf, &oid))
 139                         had_error = 1;
 140         }
 141         strbuf_release(&ref);
 142         return had_error;
 143 }
 144
 145 static int delete_replace_ref(const char *name, const char *ref,
 146                               const struct object_id *oid)
 147 {
 148         if (delete_ref(NULL, ref, oid, 0))
 149                 return 1;
 150         printf_ln(_("Deleted replace ref '%s'"), name);
 151         return 0;
 152 }
 153
 154 static int check_ref_valid(struct object_id *object,
 155                             struct object_id *prev,
 156                             struct strbuf *ref,
 157                             int force)
 158 {
 159         const char *git_replace_ref_base = ref_namespace[NAMESPACE_REPLACE].ref;
 160
 161         strbuf_reset(ref);
 162         strbuf_addf(ref, "%s%s", git_replace_ref_base, oid_to_hex(object));
 163         if (check_refname_format(ref->buf, 0))
 164                 return error(_("'%s' is not a valid ref name"), ref->buf);
 165
 166         if (read_ref(ref->buf, prev))
 167                 oidclr(prev);
 168         else if (!force)
 169                 return error(_("replace ref '%s' already exists"), ref->buf);
 170         return 0;
 171 }
 172
 173 static int replace_object_oid(const char *object_ref,
 174                                struct object_id *object,
 175                                const char *replace_ref,
 176                                struct object_id *repl,
 177                                int force)
 178 {
 179         struct object_id prev;
 180         enum object_type obj_type, repl_type;
 181         struct strbuf ref = STRBUF_INIT;
 182         struct ref_transaction *transaction;
 183         struct strbuf err = STRBUF_INIT;
 184         int res = 0;
 185
 186         obj_type = oid_object_info(the_repository, object, NULL);
 187         repl_type = oid_object_info(the_repository, repl, NULL);
 188         if (!force && obj_type != repl_type)
 189                 return error(_("Objects must be of the same type.\n"
 190                                "'%s' points to a replaced object of type '%s'\n"
 191                                "while '%s' points to a replacement object of "
 192                                "type '%s'."),
 193                              object_ref, type_name(obj_type),
 194                              replace_ref, type_name(repl_type));
 195
 196         if (check_ref_valid(object, &prev, &ref, force)) {
 197                 strbuf_release(&ref);
 198                 return -1;
 199         }
 200
 201         transaction = ref_transaction_begin(&err);
 202         if (!transaction ||
 203             ref_transaction_update(transaction, ref.buf, repl, &prev,
 204                                    0, NULL, &err) ||
 205             ref_transaction_commit(transaction, &err))
 206                 res = error("%s", err.buf);
 207
 208         ref_transaction_free(transaction);
 209         strbuf_release(&ref);
 210         return res;
 211 }
 212
 213 static int replace_object(const char *object_ref, const char *replace_ref, int force)
 214 {
 215         struct object_id object, repl;
 216
 217         if (repo_get_oid(the_repository, object_ref, &object))
 218                 return error(_("failed to resolve '%s' as a valid ref"),
 219                              object_ref);
 220         if (repo_get_oid(the_repository, replace_ref, &repl))
 221                 return error(_("failed to resolve '%s' as a valid ref"),
 222                              replace_ref);
 223
 224         return replace_object_oid(object_ref, &object, replace_ref, &repl, force);
 225 }
 226
 227 /*
 228  * Write the contents of the object named by "sha1" to the file "filename".
 229  * If "raw" is true, then the object's raw contents are printed according to
 230  * "type". Otherwise, we pretty-print the contents for human editing.
 231  */
 232 static int export_object(const struct object_id *oid, enum object_type type,
 233                           int raw, const char *filename)
 234 {
 235         struct child_process cmd = CHILD_PROCESS_INIT;
 236         int fd;
 237
 238         fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
 239         if (fd < 0)
 240                 return error_errno(_("unable to open %s for writing"), filename);
 241
 242         strvec_push(&cmd.args, "--no-replace-objects");
 243         strvec_push(&cmd.args, "cat-file");
 244         if (raw)
 245                 strvec_push(&cmd.args, type_name(type));
 246         else
 247                 strvec_push(&cmd.args, "-p");
 248         strvec_push(&cmd.args, oid_to_hex(oid));
 249         cmd.git_cmd = 1;
 250         cmd.out = fd;
 251
 252         if (run_command(&cmd))
 253                 return error(_("cat-file reported failure"));
 254         return 0;
 255 }
 256
 257 /*
 258  * Read a previously-exported (and possibly edited) object back from "filename",
 259  * interpreting it as "type", and writing the result to the object database.
 260  * The sha1 of the written object is returned via sha1.
 261  */
 262 static int import_object(struct object_id *oid, enum object_type type,
 263                           int raw, const char *filename)
 264 {
 265         int fd;
 266
 267         fd = open(filename, O_RDONLY);
 268         if (fd < 0)
 269                 return error_errno(_("unable to open %s for reading"), filename);
 270
 271         if (!raw && type == OBJ_TREE) {
 272                 struct child_process cmd = CHILD_PROCESS_INIT;
 273                 struct strbuf result = STRBUF_INIT;
 274
 275                 strvec_push(&cmd.args, "mktree");
 276                 cmd.git_cmd = 1;
 277                 cmd.in = fd;
 278                 cmd.out = -1;
 279
 280                 if (start_command(&cmd)) {
 281                         close(fd);
 282                         return error(_("unable to spawn mktree"));
 283                 }
 284
 285                 if (strbuf_read(&result, cmd.out, the_hash_algo->hexsz + 1) < 0) {
 286                         error_errno(_("unable to read from mktree"));
 287                         close(fd);
 288                         close(cmd.out);
 289                         return -1;
 290                 }
 291                 close(cmd.out);
 292
 293                 if (finish_command(&cmd)) {
 294                         strbuf_release(&result);
 295                         return error(_("mktree reported failure"));
 296                 }
 297                 if (get_oid_hex(result.buf, oid) < 0) {
 298                         strbuf_release(&result);
 299                         return error(_("mktree did not return an object name"));
 300                 }
 301
 302                 strbuf_release(&result);
 303         } else {
 304                 struct stat st;
 305                 int flags = HASH_FORMAT_CHECK | HASH_WRITE_OBJECT;
 306
 307                 if (fstat(fd, &st) < 0) {
 308                         error_errno(_("unable to fstat %s"), filename);
 309                         close(fd);
 310                         return -1;
 311                 }
 312                 if (index_fd(the_repository->index, oid, fd, &st, type, NULL, flags) < 0)
 313                         return error(_("unable to write object to database"));
 314                 /* index_fd close()s fd for us */
 315         }
 316
 317         /*
 318          * No need to close(fd) here; both run-command and index-fd
 319          * will have done it for us.
 320          */
 321         return 0;
 322 }
 323
 324 static int edit_and_replace(const char *object_ref, int force, int raw)
 325 {
 326         char *tmpfile;
 327         enum object_type type;
 328         struct object_id old_oid, new_oid, prev;
 329         struct strbuf ref = STRBUF_INIT;
 330
 331         if (repo_get_oid(the_repository, object_ref, &old_oid) < 0)
 332                 return error(_("not a valid object name: '%s'"), object_ref);
 333
 334         type = oid_object_info(the_repository, &old_oid, NULL);
 335         if (type < 0)
 336                 return error(_("unable to get object type for %s"),
 337                              oid_to_hex(&old_oid));
 338
 339         if (check_ref_valid(&old_oid, &prev, &ref, force)) {
 340                 strbuf_release(&ref);
 341                 return -1;
 342         }
 343         strbuf_release(&ref);
 344
 345         tmpfile = git_pathdup("REPLACE_EDITOBJ");
 346         if (export_object(&old_oid, type, raw, tmpfile)) {
 347                 free(tmpfile);
 348                 return -1;
 349         }
 350         if (launch_editor(tmpfile, NULL, NULL) < 0) {
 351                 free(tmpfile);
 352                 return error(_("editing object file failed"));
 353         }
 354         if (import_object(&new_oid, type, raw, tmpfile)) {
 355                 free(tmpfile);
 356                 return -1;
 357         }
 358         free(tmpfile);
 359
 360         if (oideq(&old_oid, &new_oid))
 361                 return error(_("new object is the same as the old one: '%s'"), oid_to_hex(&old_oid));
 362
 363         return replace_object_oid(object_ref, &old_oid, "replacement", &new_oid, force);
 364 }
 365
 366 static int replace_parents(struct strbuf *buf, int argc, const char **argv)
 367 {
 368         struct strbuf new_parents = STRBUF_INIT;
 369         const char *parent_start, *parent_end;
 370         int i;
 371         const unsigned hexsz = the_hash_algo->hexsz;
 372
 373         /* find existing parents */
 374         parent_start = buf->buf;
 375         parent_start += hexsz + 6; /* "tree " + "hex sha1" + "\n" */
 376         parent_end = parent_start;
 377
 378         while (starts_with(parent_end, "parent "))
 379                 parent_end += hexsz + 8; /* "parent " + "hex sha1" + "\n" */
 380
 381         /* prepare new parents */
 382         for (i = 0; i < argc; i++) {
 383                 struct object_id oid;
 384                 struct commit *commit;
 385
 386                 if (repo_get_oid(the_repository, argv[i], &oid) < 0) {
 387                         strbuf_release(&new_parents);
 388                         return error(_("not a valid object name: '%s'"),
 389                                      argv[i]);
 390                 }
 391                 commit = lookup_commit_reference(the_repository, &oid);
 392                 if (!commit) {
 393                         strbuf_release(&new_parents);
 394                         return error(_("could not parse %s as a commit"), argv[i]);
 395                 }
 396                 strbuf_addf(&new_parents, "parent %s\n", oid_to_hex(&commit->object.oid));
 397         }
 398
 399         /* replace existing parents with new ones */
 400         strbuf_splice(buf, parent_start - buf->buf, parent_end - parent_start,
 401                       new_parents.buf, new_parents.len);
 402
 403         strbuf_release(&new_parents);
 404         return 0;
 405 }
 406
 407 struct check_mergetag_data {
 408         int argc;
 409         const char **argv;
 410 };
 411
 412 static int check_one_mergetag(struct commit *commit UNUSED,
 413                                struct commit_extra_header *extra,
 414                                void *data)
 415 {
 416         struct check_mergetag_data *mergetag_data = (struct check_mergetag_data *)data;
 417         const char *ref = mergetag_data->argv[0];
 418         struct object_id tag_oid;
 419         struct tag *tag;
 420         int i;
 421
 422         hash_object_file(the_hash_algo, extra->value, extra->len,
 423                          OBJ_TAG, &tag_oid);
 424         tag = lookup_tag(the_repository, &tag_oid);
 425         if (!tag)
 426                 return error(_("bad mergetag in commit '%s'"), ref);
 427         if (parse_tag_buffer(the_repository, tag, extra->value, extra->len))
 428                 return error(_("malformed mergetag in commit '%s'"), ref);
 429
 430         /* iterate over new parents */
 431         for (i = 1; i < mergetag_data->argc; i++) {
 432                 struct object_id oid;
 433                 if (repo_get_oid(the_repository, mergetag_data->argv[i], &oid) < 0)
 434                         return error(_("not a valid object name: '%s'"),
 435                                      mergetag_data->argv[i]);
 436                 if (oideq(get_tagged_oid(tag), &oid))
 437                         return 0; /* found */
 438         }
 439
 440         return error(_("original commit '%s' contains mergetag '%s' that is "
 441                        "discarded; use --edit instead of --graft"), ref,
 442                      oid_to_hex(&tag_oid));
 443 }
 444
 445 static int check_mergetags(struct commit *commit, int argc, const char **argv)
 446 {
 447         struct check_mergetag_data mergetag_data;
 448
 449         mergetag_data.argc = argc;
 450         mergetag_data.argv = argv;
 451         return for_each_mergetag(check_one_mergetag, commit, &mergetag_data);
 452 }
 453
 454 static int create_graft(int argc, const char **argv, int force, int gentle)
 455 {
 456         struct object_id old_oid, new_oid;
 457         const char *old_ref = argv[0];
 458         struct commit *commit;
 459         struct strbuf buf = STRBUF_INIT;
 460         const char *buffer;
 461         unsigned long size;
 462
 463         if (repo_get_oid(the_repository, old_ref, &old_oid) < 0)
 464                 return error(_("not a valid object name: '%s'"), old_ref);
 465         commit = lookup_commit_reference(the_repository, &old_oid);
 466         if (!commit)
 467                 return error(_("could not parse %s"), old_ref);
 468
 469         buffer = repo_get_commit_buffer(the_repository, commit, &size);
 470         strbuf_add(&buf, buffer, size);
 471         repo_unuse_commit_buffer(the_repository, commit, buffer);
 472
 473         if (replace_parents(&buf, argc - 1, &argv[1]) < 0) {
 474                 strbuf_release(&buf);
 475                 return -1;
 476         }
 477
 478         if (remove_signature(&buf)) {
 479                 warning(_("the original commit '%s' has a gpg signature"), old_ref);
 480                 warning(_("the signature will be removed in the replacement commit!"));
 481         }
 482
 483         if (check_mergetags(commit, argc, argv)) {
 484                 strbuf_release(&buf);
 485                 return -1;
 486         }
 487
 488         if (write_object_file(buf.buf, buf.len, OBJ_COMMIT, &new_oid)) {
 489                 strbuf_release(&buf);
 490                 return error(_("could not write replacement commit for: '%s'"),
 491                              old_ref);
 492         }
 493
 494         strbuf_release(&buf);
 495
 496         if (oideq(&commit->object.oid, &new_oid)) {
 497                 if (gentle) {
 498                         warning(_("graft for '%s' unnecessary"),
 499                                 oid_to_hex(&commit->object.oid));
 500                         return 0;
 501                 }
 502                 return error(_("new commit is the same as the old one: '%s'"),
 503                              oid_to_hex(&commit->object.oid));
 504         }
 505
 506         return replace_object_oid(old_ref, &commit->object.oid,
 507                                   "replacement", &new_oid, force);
 508 }
 509
 510 static int convert_graft_file(int force)
 511 {
 512         const char *graft_file = get_graft_file(the_repository);
 513         FILE *fp = fopen_or_warn(graft_file, "r");
 514         struct strbuf buf = STRBUF_INIT, err = STRBUF_INIT;
 515         struct strvec args = STRVEC_INIT;
 516
 517         if (!fp)
 518                 return -1;
 519
 520         no_graft_file_deprecated_advice = 1;
 521         while (strbuf_getline(&buf, fp) != EOF) {
 522                 if (*buf.buf == '#')
 523                         continue;
 524
 525                 strvec_split(&args, buf.buf);
 526                 if (args.nr && create_graft(args.nr, args.v, force, 1))
 527                         strbuf_addf(&err, "\n\t%s", buf.buf);
 528                 strvec_clear(&args);
 529         }
 530         fclose(fp);
 531
 532         strbuf_release(&buf);
 533
 534         if (!err.len)
 535                 return unlink_or_warn(graft_file);
 536
 537         warning(_("could not convert the following graft(s):\n%s"), err.buf);
 538         strbuf_release(&err);
 539
 540         return -1;
 541 }
 542
 543 int cmd_replace(int argc, const char **argv, const char *prefix)
 544 {
 545         int force = 0;
 546         int raw = 0;
 547         const char *format = NULL;
 548         enum {
 549                 MODE_UNSPECIFIED = 0,
 550                 MODE_LIST,
 551                 MODE_DELETE,
 552                 MODE_EDIT,
 553                 MODE_GRAFT,
 554                 MODE_CONVERT_GRAFT_FILE,
 555                 MODE_REPLACE
 556         } cmdmode = MODE_UNSPECIFIED;
 557         struct option options[] = {
 558                 OPT_CMDMODE('l', "list", &cmdmode, N_("list replace refs"), MODE_LIST),
 559                 OPT_CMDMODE('d', "delete", &cmdmode, N_("delete replace refs"), MODE_DELETE),
 560                 OPT_CMDMODE('e', "edit", &cmdmode, N_("edit existing object"), MODE_EDIT),
 561                 OPT_CMDMODE('g', "graft", &cmdmode, N_("change a commit's parents"), MODE_GRAFT),
 562                 OPT_CMDMODE(0, "convert-graft-file", &cmdmode, N_("convert existing graft file"), MODE_CONVERT_GRAFT_FILE),
 563                 OPT_BOOL_F('f', "force", &force, N_("replace the ref if it exists"),
 564                            PARSE_OPT_NOCOMPLETE),
 565                 OPT_BOOL(0, "raw", &raw, N_("do not pretty-print contents for --edit")),
 566                 OPT_STRING(0, "format", &format, N_("format"), N_("use this format")),
 567                 OPT_END()
 568         };
 569
 570         disable_replace_refs();
 571         git_config(git_default_config, NULL);
 572
 573         argc = parse_options(argc, argv, prefix, options, git_replace_usage, 0);
 574
 575         if (!cmdmode)
 576                 cmdmode = argc ? MODE_REPLACE : MODE_LIST;
 577
 578         if (format && cmdmode != MODE_LIST)
 579                 usage_msg_opt(_("--format cannot be used when not listing"),
 580                               git_replace_usage, options);
 581
 582         if (force &&
 583             cmdmode != MODE_REPLACE &&
 584             cmdmode != MODE_EDIT &&
 585             cmdmode != MODE_GRAFT &&
 586             cmdmode != MODE_CONVERT_GRAFT_FILE)
 587                 usage_msg_opt(_("-f only makes sense when writing a replacement"),
 588                               git_replace_usage, options);
 589
 590         if (raw && cmdmode != MODE_EDIT)
 591                 usage_msg_opt(_("--raw only makes sense with --edit"),
 592                               git_replace_usage, options);
 593
 594         switch (cmdmode) {
 595         case MODE_DELETE:
 596                 if (argc < 1)
 597                         usage_msg_opt(_("-d needs at least one argument"),
 598                                       git_replace_usage, options);
 599                 return for_each_replace_name(argv, delete_replace_ref);
 600
 601         case MODE_REPLACE:
 602                 if (argc != 2)
 603                         usage_msg_opt(_("bad number of arguments"),
 604                                       git_replace_usage, options);
 605                 return replace_object(argv[0], argv[1], force);
 606
 607         case MODE_EDIT:
 608                 if (argc != 1)
 609                         usage_msg_opt(_("-e needs exactly one argument"),
 610                                       git_replace_usage, options);
 611                 return edit_and_replace(argv[0], force, raw);
 612
 613         case MODE_GRAFT:
 614                 if (argc < 1)
 615                         usage_msg_opt(_("-g needs at least one argument"),
 616                                       git_replace_usage, options);
 617                 return create_graft(argc, argv, force, 0);
 618
 619         case MODE_CONVERT_GRAFT_FILE:
 620                 if (argc != 0)
 621                         usage_msg_opt(_("--convert-graft-file takes no argument"),
 622                                       git_replace_usage, options);
 623                 return !!convert_graft_file(force);
 624
 625         case MODE_LIST:
 626                 if (argc > 1)
 627                         usage_msg_opt(_("only one pattern can be given with -l"),
 628                                       git_replace_usage, options);
 629                 return list_replace_refs(argv[0], format);
 630
 631         default:
 632                 BUG("invalid cmdmode %d", (int)cmdmode);
 633         }
 634 }