builtin/replace.c

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