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