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