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