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 "refs.h"
  15 #include "parse-options.h"
  16 #include "run-command.h"
  17 #include "object-store.h"
  18 #include "repository.h"
  19 #include "tag.h"
  20
  21 static const char * const git_replace_usage[] = {
  22         N_("git replace [-f] <object> <replacement>"),
  23         N_("git replace [-f] --edit <object>"),
  24         N_("git replace [-f] --graft <commit> [<parent>...]"),
  25         N_("git replace [-f] --convert-graft-file"),
  26         N_("git replace -d <object>..."),
  27         N_("git replace [--format=<format>] [-l [<pattern>]]"),
  28         NULL
  29 };
  30
  31 enum replace_format {
  32         REPLACE_FORMAT_SHORT,
  33         REPLACE_FORMAT_MEDIUM,
  34         REPLACE_FORMAT_LONG
  35 };
  36
  37 struct show_data {
  38         const char *pattern;
  39         enum replace_format format;
  40 };
  41
  42 static int show_reference(struct repository *r, const char *refname,
  43                           const struct object_id *oid,
  44                           int flag, void *cb_data)
  45 {
  46         struct show_data *data = cb_data;
  47
  48         if (!wildmatch(data->pattern, refname, 0)) {
  49                 if (data->format == REPLACE_FORMAT_SHORT)
  50                         printf("%s\n", refname);
  51                 else if (data->format == REPLACE_FORMAT_MEDIUM)
  52                         printf("%s -> %s\n", refname, oid_to_hex(oid));
  53                 else { /* data->format == REPLACE_FORMAT_LONG */
  54                         struct object_id object;
  55                         enum object_type obj_type, repl_type;
  56
  57                         if (get_oid(refname, &object))
  58                                 return error(_("failed to resolve '%s' as a valid ref"), refname);
  59
  60                         obj_type = oid_object_info(r, &object, NULL);
  61                         repl_type = oid_object_info(r, oid, NULL);
  62
  63                         printf("%s (%s) -> %s (%s)\n", refname, type_name(obj_type),
  64                                oid_to_hex(oid), type_name(repl_type));
  65                 }
  66         }
  67
  68         return 0;
  69 }
  70
  71 static int list_replace_refs(const char *pattern, const char *format)
  72 {
  73         struct show_data data;
  74
  75         if (pattern == NULL)
  76                 pattern = "*";
  77         data.pattern = pattern;
  78
  79         if (format == NULL || *format == '\0' || !strcmp(format, "short"))
  80                 data.format = REPLACE_FORMAT_SHORT;
  81         else if (!strcmp(format, "medium"))
  82                 data.format = REPLACE_FORMAT_MEDIUM;
  83         else if (!strcmp(format, "long"))
  84                 data.format = REPLACE_FORMAT_LONG;
  85         /*
  86          * Please update _git_replace() in git-completion.bash when
  87          * you add new format
  88          */
  89         else
  90                 return error(_("invalid replace format '%s'\n"
  91                                "valid formats are 'short', 'medium' and 'long'"),
  92                              format);
  93
  94         for_each_replace_ref(the_repository, show_reference, (void *)&data);
  95
  96         return 0;
  97 }
  98
  99 typedef int (*each_replace_name_fn)(const char *name, const char *ref,
 100                                     const struct object_id *oid);
 101
 102 static int for_each_replace_name(const char **argv, each_replace_name_fn fn)
 103 {
 104         const char **p, *full_hex;
 105         struct strbuf ref = STRBUF_INIT;
 106         size_t base_len;
 107         int had_error = 0;
 108         struct object_id oid;
 109
 110         strbuf_addstr(&ref, git_replace_ref_base);
 111         base_len = ref.len;
 112
 113         for (p = argv; *p; p++) {
 114                 if (get_oid(*p, &oid)) {
 115                         error("failed to resolve '%s' as a valid ref", *p);
 116                         had_error = 1;
 117                         continue;
 118                 }
 119
 120                 strbuf_setlen(&ref, base_len);
 121                 strbuf_addstr(&ref, oid_to_hex(&oid));
 122                 full_hex = ref.buf + base_len;
 123
 124                 if (read_ref(ref.buf, &oid)) {
 125                         error(_("replace ref '%s' not found"), full_hex);
 126                         had_error = 1;
 127                         continue;
 128                 }
 129                 if (fn(full_hex, ref.buf, &oid))
 130                         had_error = 1;
 131         }
 132         strbuf_release(&ref);
 133         return had_error;
 134 }
 135
 136 static int delete_replace_ref(const char *name, const char *ref,
 137                               const struct object_id *oid)
 138 {
 139         if (delete_ref(NULL, ref, oid, 0))
 140                 return 1;
 141         printf_ln(_("Deleted replace ref '%s'"), name);
 142         return 0;
 143 }
 144
 145 static int check_ref_valid(struct object_id *object,
 146                             struct object_id *prev,
 147                             struct strbuf *ref,
 148                             int force)
 149 {
 150         strbuf_reset(ref);
 151         strbuf_addf(ref, "%s%s", git_replace_ref_base, oid_to_hex(object));
 152         if (check_refname_format(ref->buf, 0))
 153                 return error(_("'%s' is not a valid ref name"), ref->buf);
 154
 155         if (read_ref(ref->buf, prev))
 156                 oidclr(prev);
 157         else if (!force)
 158                 return error(_("replace ref '%s' already exists"), ref->buf);
 159         return 0;
 160 }
 161
 162 static int replace_object_oid(const char *object_ref,
 163                                struct object_id *object,
 164                                const char *replace_ref,
 165                                struct object_id *repl,
 166                                int force)
 167 {
 168         struct object_id prev;
 169         enum object_type obj_type, repl_type;
 170         struct strbuf ref = STRBUF_INIT;
 171         struct ref_transaction *transaction;
 172         struct strbuf err = STRBUF_INIT;
 173         int res = 0;
 174
 175         obj_type = oid_object_info(the_repository, object, NULL);
 176         repl_type = oid_object_info(the_repository, repl, NULL);
 177         if (!force && obj_type != repl_type)
 178                 return error(_("Objects must be of the same type.\n"
 179                                "'%s' points to a replaced object of type '%s'\n"
 180                                "while '%s' points to a replacement object of "
 181                                "type '%s'."),
 182                              object_ref, type_name(obj_type),
 183                              replace_ref, type_name(repl_type));
 184
 185         if (check_ref_valid(object, &prev, &ref, force)) {
 186                 strbuf_release(&ref);
 187                 return -1;
 188         }
 189
 190         transaction = ref_transaction_begin(&err);
 191         if (!transaction ||
 192             ref_transaction_update(transaction, ref.buf, repl, &prev,
 193                                    0, NULL, &err) ||
 194             ref_transaction_commit(transaction, &err))
 195                 res = error("%s", err.buf);
 196
 197         ref_transaction_free(transaction);
 198         strbuf_release(&ref);
 199         return res;
 200 }
 201
 202 static int replace_object(const char *object_ref, const char *replace_ref, int force)
 203 {
 204         struct object_id object, repl;
 205
 206         if (get_oid(object_ref, &object))
 207                 return error(_("failed to resolve '%s' as a valid ref"),
 208                              object_ref);
 209         if (get_oid(replace_ref, &repl))
 210                 return error(_("failed to resolve '%s' as a valid ref"),
 211                              replace_ref);
 212
 213         return replace_object_oid(object_ref, &object, replace_ref, &repl, force);
 214 }
 215
 216 /*
 217  * Write the contents of the object named by "sha1" to the file "filename".
 218  * If "raw" is true, then the object's raw contents are printed according to
 219  * "type". Otherwise, we pretty-print the contents for human editing.
 220  */
 221 static int export_object(const struct object_id *oid, enum object_type type,
 222                           int raw, const char *filename)
 223 {
 224         struct child_process cmd = CHILD_PROCESS_INIT;
 225         int fd;
 226
 227         fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
 228         if (fd < 0)
 229                 return error_errno(_("unable to open %s for writing"), filename);
 230
 231         argv_array_push(&cmd.args, "--no-replace-objects");
 232         argv_array_push(&cmd.args, "cat-file");
 233         if (raw)
 234                 argv_array_push(&cmd.args, type_name(type));
 235         else
 236                 argv_array_push(&cmd.args, "-p");
 237         argv_array_push(&cmd.args, oid_to_hex(oid));
 238         cmd.git_cmd = 1;
 239         cmd.out = fd;
 240
 241         if (run_command(&cmd))
 242                 return error(_("cat-file reported failure"));
 243         return 0;
 244 }
 245
 246 /*
 247  * Read a previously-exported (and possibly edited) object back from "filename",
 248  * interpreting it as "type", and writing the result to the object database.
 249  * The sha1 of the written object is returned via sha1.
 250  */
 251 static int import_object(struct object_id *oid, enum object_type type,
 252                           int raw, const char *filename)
 253 {
 254         int fd;
 255
 256         fd = open(filename, O_RDONLY);
 257         if (fd < 0)
 258                 return error_errno(_("unable to open %s for reading"), filename);
 259
 260         if (!raw && type == OBJ_TREE) {
 261                 const char *argv[] = { "mktree", NULL };
 262                 struct child_process cmd = CHILD_PROCESS_INIT;
 263                 struct strbuf result = STRBUF_INIT;
 264
 265                 cmd.argv = argv;
 266                 cmd.git_cmd = 1;
 267                 cmd.in = fd;
 268                 cmd.out = -1;
 269
 270                 if (start_command(&cmd)) {
 271                         close(fd);
 272                         return error(_("unable to spawn mktree"));
 273                 }
 274
 275                 if (strbuf_read(&result, cmd.out, 41) < 0) {
 276                         error_errno(_("unable to read from mktree"));
 277                         close(fd);
 278                         close(cmd.out);
 279                         return -1;
 280                 }
 281                 close(cmd.out);
 282
 283                 if (finish_command(&cmd)) {
 284                         strbuf_release(&result);
 285                         return error(_("mktree reported failure"));
 286                 }
 287                 if (get_oid_hex(result.buf, oid) < 0) {
 288                         strbuf_release(&result);
 289                         return error(_("mktree did not return an object name"));
 290                 }
 291
 292                 strbuf_release(&result);
 293         } else {
 294                 struct stat st;
 295                 int flags = HASH_FORMAT_CHECK | HASH_WRITE_OBJECT;
 296
 297                 if (fstat(fd, &st) < 0) {
 298                         error_errno(_("unable to fstat %s"), filename);
 299                         close(fd);
 300                         return -1;
 301                 }
 302                 if (index_fd(the_repository->index, oid, fd, &st, type, NULL, flags) < 0)
 303                         return error(_("unable to write object to database"));
 304                 /* index_fd close()s fd for us */
 305         }
 306
 307         /*
 308          * No need to close(fd) here; both run-command and index-fd
 309          * will have done it for us.
 310          */
 311         return 0;
 312 }
 313
 314 static int edit_and_replace(const char *object_ref, int force, int raw)
 315 {
 316         char *tmpfile;
 317         enum object_type type;
 318         struct object_id old_oid, new_oid, prev;
 319         struct strbuf ref = STRBUF_INIT;
 320
 321         if (get_oid(object_ref, &old_oid) < 0)
 322                 return error(_("not a valid object name: '%s'"), object_ref);
 323
 324         type = oid_object_info(the_repository, &old_oid, NULL);
 325         if (type < 0)
 326                 return error(_("unable to get object type for %s"),
 327                              oid_to_hex(&old_oid));
 328
 329         if (check_ref_valid(&old_oid, &prev, &ref, force)) {
 330                 strbuf_release(&ref);
 331                 return -1;
 332         }
 333         strbuf_release(&ref);
 334
 335         tmpfile = git_pathdup("REPLACE_EDITOBJ");
 336         if (export_object(&old_oid, type, raw, tmpfile)) {
 337                 free(tmpfile);
 338                 return -1;
 339         }
 340         if (launch_editor(tmpfile, NULL, NULL) < 0) {
 341                 free(tmpfile);
 342                 return error(_("editing object file failed"));
 343         }
 344         if (import_object(&new_oid, type, raw, tmpfile)) {
 345                 free(tmpfile);
 346                 return -1;
 347         }
 348         free(tmpfile);
 349
 350         if (oideq(&old_oid, &new_oid))
 351                 return error(_("new object is the same as the old one: '%s'"), oid_to_hex(&old_oid));
 352
 353         return replace_object_oid(object_ref, &old_oid, "replacement", &new_oid, force);
 354 }
 355
 356 static int replace_parents(struct strbuf *buf, int argc, const char **argv)
 357 {
 358         struct strbuf new_parents = STRBUF_INIT;
 359         const char *parent_start, *parent_end;
 360         int i;
 361
 362         /* find existing parents */
 363         parent_start = buf->buf;
 364         parent_start += GIT_SHA1_HEXSZ + 6; /* "tree " + "hex sha1" + "\n" */
 365         parent_end = parent_start;
 366
 367         while (starts_with(parent_end, "parent "))
 368                 parent_end += 48; /* "parent " + "hex sha1" + "\n" */
 369
 370         /* prepare new parents */
 371         for (i = 0; i < argc; i++) {
 372                 struct object_id oid;
 373                 struct commit *commit;
 374
 375                 if (get_oid(argv[i], &oid) < 0) {
 376                         strbuf_release(&new_parents);
 377                         return error(_("not a valid object name: '%s'"),
 378                                      argv[i]);
 379                 }
 380                 commit = lookup_commit_reference(the_repository, &oid);
 381                 if (!commit) {
 382                         strbuf_release(&new_parents);
 383                         return error(_("could not parse %s as a commit"), argv[i]);
 384                 }
 385                 strbuf_addf(&new_parents, "parent %s\n", oid_to_hex(&commit->object.oid));
 386         }
 387
 388         /* replace existing parents with new ones */
 389         strbuf_splice(buf, parent_start - buf->buf, parent_end - parent_start,
 390                       new_parents.buf, new_parents.len);
 391
 392         strbuf_release(&new_parents);
 393         return 0;
 394 }
 395
 396 struct check_mergetag_data {
 397         int argc;
 398         const char **argv;
 399 };
 400
 401 static int check_one_mergetag(struct commit *commit,
 402                                struct commit_extra_header *extra,
 403                                void *data)
 404 {
 405         struct check_mergetag_data *mergetag_data = (struct check_mergetag_data *)data;
 406         const char *ref = mergetag_data->argv[0];
 407         struct object_id tag_oid;
 408         struct tag *tag;
 409         int i;
 410
 411         hash_object_file(extra->value, extra->len, type_name(OBJ_TAG), &tag_oid);
 412         tag = lookup_tag(the_repository, &tag_oid);
 413         if (!tag)
 414                 return error(_("bad mergetag in commit '%s'"), ref);
 415         if (parse_tag_buffer(the_repository, tag, extra->value, extra->len))
 416                 return error(_("malformed mergetag in commit '%s'"), ref);
 417
 418         /* iterate over new parents */
 419         for (i = 1; i < mergetag_data->argc; i++) {
 420                 struct object_id oid;
 421                 if (get_oid(mergetag_data->argv[i], &oid) < 0)
 422                         return error(_("not a valid object name: '%s'"),
 423                                      mergetag_data->argv[i]);
 424                 if (oideq(&tag->tagged->oid, &oid))
 425                         return 0; /* found */
 426         }
 427
 428         return error(_("original commit '%s' contains mergetag '%s' that is "
 429                        "discarded; use --edit instead of --graft"), ref,
 430                      oid_to_hex(&tag_oid));
 431 }
 432
 433 static int check_mergetags(struct commit *commit, int argc, const char **argv)
 434 {
 435         struct check_mergetag_data mergetag_data;
 436
 437         mergetag_data.argc = argc;
 438         mergetag_data.argv = argv;
 439         return for_each_mergetag(check_one_mergetag, commit, &mergetag_data);
 440 }
 441
 442 static int create_graft(int argc, const char **argv, int force, int gentle)
 443 {
 444         struct object_id old_oid, new_oid;
 445         const char *old_ref = argv[0];
 446         struct commit *commit;
 447         struct strbuf buf = STRBUF_INIT;
 448         const char *buffer;
 449         unsigned long size;
 450
 451         if (get_oid(old_ref, &old_oid) < 0)
 452                 return error(_("not a valid object name: '%s'"), old_ref);
 453         commit = lookup_commit_reference(the_repository, &old_oid);
 454         if (!commit)
 455                 return error(_("could not parse %s"), old_ref);
 456
 457         buffer = get_commit_buffer(commit, &size);
 458         strbuf_add(&buf, buffer, size);
 459         unuse_commit_buffer(commit, buffer);
 460
 461         if (replace_parents(&buf, argc - 1, &argv[1]) < 0) {
 462                 strbuf_release(&buf);
 463                 return -1;
 464         }
 465
 466         if (remove_signature(&buf)) {
 467                 warning(_("the original commit '%s' has a gpg signature"), old_ref);
 468                 warning(_("the signature will be removed in the replacement commit!"));
 469         }
 470
 471         if (check_mergetags(commit, argc, argv)) {
 472                 strbuf_release(&buf);
 473                 return -1;
 474         }
 475
 476         if (write_object_file(buf.buf, buf.len, commit_type, &new_oid)) {
 477                 strbuf_release(&buf);
 478                 return error(_("could not write replacement commit for: '%s'"),
 479                              old_ref);
 480         }
 481
 482         strbuf_release(&buf);
 483
 484         if (oideq(&commit->object.oid, &new_oid)) {
 485                 if (gentle) {
 486                         warning(_("graft for '%s' unnecessary"),
 487                                 oid_to_hex(&commit->object.oid));
 488                         return 0;
 489                 }
 490                 return error(_("new commit is the same as the old one: '%s'"),
 491                              oid_to_hex(&commit->object.oid));
 492         }
 493
 494         return replace_object_oid(old_ref, &commit->object.oid,
 495                                   "replacement", &new_oid, force);
 496 }
 497
 498 static int convert_graft_file(int force)
 499 {
 500         const char *graft_file = get_graft_file(the_repository);
 501         FILE *fp = fopen_or_warn(graft_file, "r");
 502         struct strbuf buf = STRBUF_INIT, err = STRBUF_INIT;
 503         struct argv_array args = ARGV_ARRAY_INIT;
 504
 505         if (!fp)
 506                 return -1;
 507
 508         advice_graft_file_deprecated = 0;
 509         while (strbuf_getline(&buf, fp) != EOF) {
 510                 if (*buf.buf == '#')
 511                         continue;
 512
 513                 argv_array_split(&args, buf.buf);
 514                 if (args.argc && create_graft(args.argc, args.argv, force, 1))
 515                         strbuf_addf(&err, "\n\t%s", buf.buf);
 516                 argv_array_clear(&args);
 517         }
 518         fclose(fp);
 519
 520         strbuf_release(&buf);
 521
 522         if (!err.len)
 523                 return unlink_or_warn(graft_file);
 524
 525         warning(_("could not convert the following graft(s):\n%s"), err.buf);
 526         strbuf_release(&err);
 527
 528         return -1;
 529 }
 530
 531 int cmd_replace(int argc, const char **argv, const char *prefix)
 532 {
 533         int force = 0;
 534         int raw = 0;
 535         const char *format = NULL;
 536         enum {
 537                 MODE_UNSPECIFIED = 0,
 538                 MODE_LIST,
 539                 MODE_DELETE,
 540                 MODE_EDIT,
 541                 MODE_GRAFT,
 542                 MODE_CONVERT_GRAFT_FILE,
 543                 MODE_REPLACE
 544         } cmdmode = MODE_UNSPECIFIED;
 545         struct option options[] = {
 546                 OPT_CMDMODE('l', "list", &cmdmode, N_("list replace refs"), MODE_LIST),
 547                 OPT_CMDMODE('d', "delete", &cmdmode, N_("delete replace refs"), MODE_DELETE),
 548                 OPT_CMDMODE('e', "edit", &cmdmode, N_("edit existing object"), MODE_EDIT),
 549                 OPT_CMDMODE('g', "graft", &cmdmode, N_("change a commit's parents"), MODE_GRAFT),
 550                 OPT_CMDMODE(0, "convert-graft-file", &cmdmode, N_("convert existing graft file"), MODE_CONVERT_GRAFT_FILE),
 551                 OPT_BOOL_F('f', "force", &force, N_("replace the ref if it exists"),
 552                            PARSE_OPT_NOCOMPLETE),
 553                 OPT_BOOL(0, "raw", &raw, N_("do not pretty-print contents for --edit")),
 554                 OPT_STRING(0, "format", &format, N_("format"), N_("use this format")),
 555                 OPT_END()
 556         };
 557
 558         read_replace_refs = 0;
 559         git_config(git_default_config, NULL);
 560
 561         argc = parse_options(argc, argv, prefix, options, git_replace_usage, 0);
 562
 563         if (!cmdmode)
 564                 cmdmode = argc ? MODE_REPLACE : MODE_LIST;
 565
 566         if (format && cmdmode != MODE_LIST)
 567                 usage_msg_opt(_("--format cannot be used when not listing"),
 568                               git_replace_usage, options);
 569
 570         if (force &&
 571             cmdmode != MODE_REPLACE &&
 572             cmdmode != MODE_EDIT &&
 573             cmdmode != MODE_GRAFT &&
 574             cmdmode != MODE_CONVERT_GRAFT_FILE)
 575                 usage_msg_opt(_("-f only makes sense when writing a replacement"),
 576                               git_replace_usage, options);
 577
 578         if (raw && cmdmode != MODE_EDIT)
 579                 usage_msg_opt(_("--raw only makes sense with --edit"),
 580                               git_replace_usage, options);
 581
 582         switch (cmdmode) {
 583         case MODE_DELETE:
 584                 if (argc < 1)
 585                         usage_msg_opt(_("-d needs at least one argument"),
 586                                       git_replace_usage, options);
 587                 return for_each_replace_name(argv, delete_replace_ref);
 588
 589         case MODE_REPLACE:
 590                 if (argc != 2)
 591                         usage_msg_opt(_("bad number of arguments"),
 592                                       git_replace_usage, options);
 593                 return replace_object(argv[0], argv[1], force);
 594
 595         case MODE_EDIT:
 596                 if (argc != 1)
 597                         usage_msg_opt(_("-e needs exactly one argument"),
 598                                       git_replace_usage, options);
 599                 return edit_and_replace(argv[0], force, raw);
 600
 601         case MODE_GRAFT:
 602                 if (argc < 1)
 603                         usage_msg_opt(_("-g needs at least one argument"),
 604                                       git_replace_usage, options);
 605                 return create_graft(argc, argv, force, 0);
 606
 607         case MODE_CONVERT_GRAFT_FILE:
 608                 if (argc != 0)
 609                         usage_msg_opt(_("--convert-graft-file takes no argument"),
 610                                       git_replace_usage, options);
 611                 return !!convert_graft_file(force);
 612
 613         case MODE_LIST:
 614                 if (argc > 1)
 615                         usage_msg_opt(_("only one pattern can be given with -l"),
 616                                       git_replace_usage, options);
 617                 return list_replace_refs(argv[0], format);
 618
 619         default:
 620                 BUG("invalid cmdmode %d", (int)cmdmode);
 621         }
 622 }