Andrew's git - gitweb.git/blob

   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 "builtin.h"
  13#include "refs.h"
  14#include "parse-options.h"
  15#include "run-command.h"
  16#include "tag.h"
  17
  18static const char * const git_replace_usage[] = {
  19        N_("git replace [-f] <object> <replacement>"),
  20        N_("git replace [-f] --edit <object>"),
  21        N_("git replace [-f] --graft <commit> [<parent>...]"),
  22        N_("git replace -d <object>..."),
  23        N_("git replace [--format=<format>] [-l [<pattern>]]"),
  24        NULL
  25};
  26
  27enum replace_format {
  28        REPLACE_FORMAT_SHORT,
  29        REPLACE_FORMAT_MEDIUM,
  30        REPLACE_FORMAT_LONG
  31};
  32
  33struct show_data {
  34        const char *pattern;
  35        enum replace_format format;
  36};
  37
  38static int show_reference(const char *refname, const struct object_id *oid,
  39                          int flag, void *cb_data)
  40{
  41        struct show_data *data = cb_data;
  42
  43        if (!wildmatch(data->pattern, refname, 0, NULL)) {
  44                if (data->format == REPLACE_FORMAT_SHORT)
  45                        printf("%s\n", refname);
  46                else if (data->format == REPLACE_FORMAT_MEDIUM)
  47                        printf("%s -> %s\n", refname, oid_to_hex(oid));
  48                else { /* data->format == REPLACE_FORMAT_LONG */
  49                        struct object_id object;
  50                        enum object_type obj_type, repl_type;
  51
  52                        if (get_sha1(refname, object.hash))
  53                                return error("Failed to resolve '%s' as a valid ref.", refname);
  54
  55                        obj_type = sha1_object_info(object.hash, NULL);
  56                        repl_type = sha1_object_info(oid->hash, NULL);
  57
  58                        printf("%s (%s) -> %s (%s)\n", refname, typename(obj_type),
  59                               oid_to_hex(oid), typename(repl_type));
  60                }
  61        }
  62
  63        return 0;
  64}
  65
  66static int list_replace_refs(const char *pattern, const char *format)
  67{
  68        struct show_data data;
  69
  70        if (pattern == NULL)
  71                pattern = "*";
  72        data.pattern = pattern;
  73
  74        if (format == NULL || *format == '\0' || !strcmp(format, "short"))
  75                data.format = REPLACE_FORMAT_SHORT;
  76        else if (!strcmp(format, "medium"))
  77                data.format = REPLACE_FORMAT_MEDIUM;
  78        else if (!strcmp(format, "long"))
  79                data.format = REPLACE_FORMAT_LONG;
  80        else
  81                die("invalid replace format '%s'\n"
  82                    "valid formats are 'short', 'medium' and 'long'\n",
  83                    format);
  84
  85        for_each_replace_ref(show_reference, (void *)&data);
  86
  87        return 0;
  88}
  89
  90typedef int (*each_replace_name_fn)(const char *name, const char *ref,
  91                                    const unsigned char *sha1);
  92
  93static int for_each_replace_name(const char **argv, each_replace_name_fn fn)
  94{
  95        const char **p, *full_hex;
  96        char ref[PATH_MAX];
  97        int had_error = 0;
  98        unsigned char sha1[20];
  99
 100        for (p = argv; *p; p++) {
 101                if (get_sha1(*p, sha1)) {
 102                        error("Failed to resolve '%s' as a valid ref.", *p);
 103                        had_error = 1;
 104                        continue;
 105                }
 106                full_hex = sha1_to_hex(sha1);
 107                snprintf(ref, sizeof(ref), "%s%s", git_replace_ref_base, full_hex);
 108                /* read_ref() may reuse the buffer */
 109                full_hex = ref + strlen(git_replace_ref_base);
 110                if (read_ref(ref, sha1)) {
 111                        error("replace ref '%s' not found.", full_hex);
 112                        had_error = 1;
 113                        continue;
 114                }
 115                if (fn(full_hex, ref, sha1))
 116                        had_error = 1;
 117        }
 118        return had_error;
 119}
 120
 121static int delete_replace_ref(const char *name, const char *ref,
 122                              const unsigned char *sha1)
 123{
 124        if (delete_ref(ref, sha1, 0))
 125                return 1;
 126        printf("Deleted replace ref '%s'\n", name);
 127        return 0;
 128}
 129
 130static void check_ref_valid(unsigned char object[20],
 131                            unsigned char prev[20],
 132                            char *ref,
 133                            int ref_size,
 134                            int force)
 135{
 136        if (snprintf(ref, ref_size,
 137                     "%s%s", git_replace_ref_base,
 138                     sha1_to_hex(object)) > ref_size - 1)
 139                die("replace ref name too long: %.*s...", 50, ref);
 140        if (check_refname_format(ref, 0))
 141                die("'%s' is not a valid ref name.", ref);
 142
 143        if (read_ref(ref, prev))
 144                hashclr(prev);
 145        else if (!force)
 146                die("replace ref '%s' already exists", ref);
 147}
 148
 149static int replace_object_sha1(const char *object_ref,
 150                               unsigned char object[20],
 151                               const char *replace_ref,
 152                               unsigned char repl[20],
 153                               int force)
 154{
 155        unsigned char prev[20];
 156        enum object_type obj_type, repl_type;
 157        char ref[PATH_MAX];
 158        struct ref_transaction *transaction;
 159        struct strbuf err = STRBUF_INIT;
 160
 161        obj_type = sha1_object_info(object, NULL);
 162        repl_type = sha1_object_info(repl, NULL);
 163        if (!force && obj_type != repl_type)
 164                die("Objects must be of the same type.\n"
 165                    "'%s' points to a replaced object of type '%s'\n"
 166                    "while '%s' points to a replacement object of type '%s'.",
 167                    object_ref, typename(obj_type),
 168                    replace_ref, typename(repl_type));
 169
 170        check_ref_valid(object, prev, ref, sizeof(ref), force);
 171
 172        transaction = ref_transaction_begin(&err);
 173        if (!transaction ||
 174            ref_transaction_update(transaction, ref, repl, prev,
 175                                   0, NULL, &err) ||
 176            ref_transaction_commit(transaction, &err))
 177                die("%s", err.buf);
 178
 179        ref_transaction_free(transaction);
 180        return 0;
 181}
 182
 183static int replace_object(const char *object_ref, const char *replace_ref, int force)
 184{
 185        unsigned char object[20], repl[20];
 186
 187        if (get_sha1(object_ref, object))
 188                die("Failed to resolve '%s' as a valid ref.", object_ref);
 189        if (get_sha1(replace_ref, repl))
 190                die("Failed to resolve '%s' as a valid ref.", replace_ref);
 191
 192        return replace_object_sha1(object_ref, object, replace_ref, repl, force);
 193}
 194
 195/*
 196 * Write the contents of the object named by "sha1" to the file "filename".
 197 * If "raw" is true, then the object's raw contents are printed according to
 198 * "type". Otherwise, we pretty-print the contents for human editing.
 199 */
 200static void export_object(const unsigned char *sha1, enum object_type type,
 201                          int raw, const char *filename)
 202{
 203        struct child_process cmd = CHILD_PROCESS_INIT;
 204        int fd;
 205
 206        fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
 207        if (fd < 0)
 208                die_errno("unable to open %s for writing", filename);
 209
 210        argv_array_push(&cmd.args, "--no-replace-objects");
 211        argv_array_push(&cmd.args, "cat-file");
 212        if (raw)
 213                argv_array_push(&cmd.args, typename(type));
 214        else
 215                argv_array_push(&cmd.args, "-p");
 216        argv_array_push(&cmd.args, sha1_to_hex(sha1));
 217        cmd.git_cmd = 1;
 218        cmd.out = fd;
 219
 220        if (run_command(&cmd))
 221                die("cat-file reported failure");
 222}
 223
 224/*
 225 * Read a previously-exported (and possibly edited) object back from "filename",
 226 * interpreting it as "type", and writing the result to the object database.
 227 * The sha1 of the written object is returned via sha1.
 228 */
 229static void import_object(unsigned char *sha1, enum object_type type,
 230                          int raw, const char *filename)
 231{
 232        int fd;
 233
 234        fd = open(filename, O_RDONLY);
 235        if (fd < 0)
 236                die_errno("unable to open %s for reading", filename);
 237
 238        if (!raw && type == OBJ_TREE) {
 239                const char *argv[] = { "mktree", NULL };
 240                struct child_process cmd = CHILD_PROCESS_INIT;
 241                struct strbuf result = STRBUF_INIT;
 242
 243                cmd.argv = argv;
 244                cmd.git_cmd = 1;
 245                cmd.in = fd;
 246                cmd.out = -1;
 247
 248                if (start_command(&cmd))
 249                        die("unable to spawn mktree");
 250
 251                if (strbuf_read(&result, cmd.out, 41) < 0)
 252                        die_errno("unable to read from mktree");
 253                close(cmd.out);
 254
 255                if (finish_command(&cmd))
 256                        die("mktree reported failure");
 257                if (get_sha1_hex(result.buf, sha1) < 0)
 258                        die("mktree did not return an object name");
 259
 260                strbuf_release(&result);
 261        } else {
 262                struct stat st;
 263                int flags = HASH_FORMAT_CHECK | HASH_WRITE_OBJECT;
 264
 265                if (fstat(fd, &st) < 0)
 266                        die_errno("unable to fstat %s", filename);
 267                if (index_fd(sha1, fd, &st, type, NULL, flags) < 0)
 268                        die("unable to write object to database");
 269                /* index_fd close()s fd for us */
 270        }
 271
 272        /*
 273         * No need to close(fd) here; both run-command and index-fd
 274         * will have done it for us.
 275         */
 276}
 277
 278static int edit_and_replace(const char *object_ref, int force, int raw)
 279{
 280        char *tmpfile = git_pathdup("REPLACE_EDITOBJ");
 281        enum object_type type;
 282        unsigned char old[20], new[20], prev[20];
 283        char ref[PATH_MAX];
 284
 285        if (get_sha1(object_ref, old) < 0)
 286                die("Not a valid object name: '%s'", object_ref);
 287
 288        type = sha1_object_info(old, NULL);
 289        if (type < 0)
 290                die("unable to get object type for %s", sha1_to_hex(old));
 291
 292        check_ref_valid(old, prev, ref, sizeof(ref), force);
 293
 294        export_object(old, type, raw, tmpfile);
 295        if (launch_editor(tmpfile, NULL, NULL) < 0)
 296                die("editing object file failed");
 297        import_object(new, type, raw, tmpfile);
 298
 299        free(tmpfile);
 300
 301        if (!hashcmp(old, new))
 302                return error("new object is the same as the old one: '%s'", sha1_to_hex(old));
 303
 304        return replace_object_sha1(object_ref, old, "replacement", new, force);
 305}
 306
 307static void replace_parents(struct strbuf *buf, int argc, const char **argv)
 308{
 309        struct strbuf new_parents = STRBUF_INIT;
 310        const char *parent_start, *parent_end;
 311        int i;
 312
 313        /* find existing parents */
 314        parent_start = buf->buf;
 315        parent_start += 46; /* "tree " + "hex sha1" + "\n" */
 316        parent_end = parent_start;
 317
 318        while (starts_with(parent_end, "parent "))
 319                parent_end += 48; /* "parent " + "hex sha1" + "\n" */
 320
 321        /* prepare new parents */
 322        for (i = 0; i < argc; i++) {
 323                unsigned char sha1[20];
 324                if (get_sha1(argv[i], sha1) < 0)
 325                        die(_("Not a valid object name: '%s'"), argv[i]);
 326                lookup_commit_or_die(sha1, argv[i]);
 327                strbuf_addf(&new_parents, "parent %s\n", sha1_to_hex(sha1));
 328        }
 329
 330        /* replace existing parents with new ones */
 331        strbuf_splice(buf, parent_start - buf->buf, parent_end - parent_start,
 332                      new_parents.buf, new_parents.len);
 333
 334        strbuf_release(&new_parents);
 335}
 336
 337struct check_mergetag_data {
 338        int argc;
 339        const char **argv;
 340};
 341
 342static void check_one_mergetag(struct commit *commit,
 343                               struct commit_extra_header *extra,
 344                               void *data)
 345{
 346        struct check_mergetag_data *mergetag_data = (struct check_mergetag_data *)data;
 347        const char *ref = mergetag_data->argv[0];
 348        unsigned char tag_sha1[20];
 349        struct tag *tag;
 350        int i;
 351
 352        hash_sha1_file(extra->value, extra->len, typename(OBJ_TAG), tag_sha1);
 353        tag = lookup_tag(tag_sha1);
 354        if (!tag)
 355                die(_("bad mergetag in commit '%s'"), ref);
 356        if (parse_tag_buffer(tag, extra->value, extra->len))
 357                die(_("malformed mergetag in commit '%s'"), ref);
 358
 359        /* iterate over new parents */
 360        for (i = 1; i < mergetag_data->argc; i++) {
 361                struct object_id oid;
 362                if (get_sha1(mergetag_data->argv[i], oid.hash) < 0)
 363                        die(_("Not a valid object name: '%s'"), mergetag_data->argv[i]);
 364                if (!oidcmp(&tag->tagged->oid, &oid))
 365                        return; /* found */
 366        }
 367
 368        die(_("original commit '%s' contains mergetag '%s' that is discarded; "
 369              "use --edit instead of --graft"), ref, sha1_to_hex(tag_sha1));
 370}
 371
 372static void check_mergetags(struct commit *commit, int argc, const char **argv)
 373{
 374        struct check_mergetag_data mergetag_data;
 375
 376        mergetag_data.argc = argc;
 377        mergetag_data.argv = argv;
 378        for_each_mergetag(check_one_mergetag, commit, &mergetag_data);
 379}
 380
 381static int create_graft(int argc, const char **argv, int force)
 382{
 383        unsigned char old[20], new[20];
 384        const char *old_ref = argv[0];
 385        struct commit *commit;
 386        struct strbuf buf = STRBUF_INIT;
 387        const char *buffer;
 388        unsigned long size;
 389
 390        if (get_sha1(old_ref, old) < 0)
 391                die(_("Not a valid object name: '%s'"), old_ref);
 392        commit = lookup_commit_or_die(old, old_ref);
 393
 394        buffer = get_commit_buffer(commit, &size);
 395        strbuf_add(&buf, buffer, size);
 396        unuse_commit_buffer(commit, buffer);
 397
 398        replace_parents(&buf, argc - 1, &argv[1]);
 399
 400        if (remove_signature(&buf)) {
 401                warning(_("the original commit '%s' has a gpg signature."), old_ref);
 402                warning(_("the signature will be removed in the replacement commit!"));
 403        }
 404
 405        check_mergetags(commit, argc, argv);
 406
 407        if (write_sha1_file(buf.buf, buf.len, commit_type, new))
 408                die(_("could not write replacement commit for: '%s'"), old_ref);
 409
 410        strbuf_release(&buf);
 411
 412        if (!hashcmp(old, new))
 413                return error("new commit is the same as the old one: '%s'", sha1_to_hex(old));
 414
 415        return replace_object_sha1(old_ref, old, "replacement", new, force);
 416}
 417
 418int cmd_replace(int argc, const char **argv, const char *prefix)
 419{
 420        int force = 0;
 421        int raw = 0;
 422        const char *format = NULL;
 423        enum {
 424                MODE_UNSPECIFIED = 0,
 425                MODE_LIST,
 426                MODE_DELETE,
 427                MODE_EDIT,
 428                MODE_GRAFT,
 429                MODE_REPLACE
 430        } cmdmode = MODE_UNSPECIFIED;
 431        struct option options[] = {
 432                OPT_CMDMODE('l', "list", &cmdmode, N_("list replace refs"), MODE_LIST),
 433                OPT_CMDMODE('d', "delete", &cmdmode, N_("delete replace refs"), MODE_DELETE),
 434                OPT_CMDMODE('e', "edit", &cmdmode, N_("edit existing object"), MODE_EDIT),
 435                OPT_CMDMODE('g', "graft", &cmdmode, N_("change a commit's parents"), MODE_GRAFT),
 436                OPT_BOOL('f', "force", &force, N_("replace the ref if it exists")),
 437                OPT_BOOL(0, "raw", &raw, N_("do not pretty-print contents for --edit")),
 438                OPT_STRING(0, "format", &format, N_("format"), N_("use this format")),
 439                OPT_END()
 440        };
 441
 442        check_replace_refs = 0;
 443
 444        argc = parse_options(argc, argv, prefix, options, git_replace_usage, 0);
 445
 446        if (!cmdmode)
 447                cmdmode = argc ? MODE_REPLACE : MODE_LIST;
 448
 449        if (format && cmdmode != MODE_LIST)
 450                usage_msg_opt("--format cannot be used when not listing",
 451                              git_replace_usage, options);
 452
 453        if (force &&
 454            cmdmode != MODE_REPLACE &&
 455            cmdmode != MODE_EDIT &&
 456            cmdmode != MODE_GRAFT)
 457                usage_msg_opt("-f only makes sense when writing a replacement",
 458                              git_replace_usage, options);
 459
 460        if (raw && cmdmode != MODE_EDIT)
 461                usage_msg_opt("--raw only makes sense with --edit",
 462                              git_replace_usage, options);
 463
 464        switch (cmdmode) {
 465        case MODE_DELETE:
 466                if (argc < 1)
 467                        usage_msg_opt("-d needs at least one argument",
 468                                      git_replace_usage, options);
 469                return for_each_replace_name(argv, delete_replace_ref);
 470
 471        case MODE_REPLACE:
 472                if (argc != 2)
 473                        usage_msg_opt("bad number of arguments",
 474                                      git_replace_usage, options);
 475                return replace_object(argv[0], argv[1], force);
 476
 477        case MODE_EDIT:
 478                if (argc != 1)
 479                        usage_msg_opt("-e needs exactly one argument",
 480                                      git_replace_usage, options);
 481                return edit_and_replace(argv[0], force, raw);
 482
 483        case MODE_GRAFT:
 484                if (argc < 1)
 485                        usage_msg_opt("-g needs at least one argument",
 486                                      git_replace_usage, options);
 487                return create_graft(argc, argv, force);
 488
 489        case MODE_LIST:
 490                if (argc > 1)
 491                        usage_msg_opt("only one pattern can be given with -l",
 492                                      git_replace_usage, options);
 493                return list_replace_refs(argv[0], format);
 494
 495        default:
 496                die("BUG: invalid cmdmode %d", (int)cmdmode);
 497        }
 498}