builtin / reset.con commit for_each_string_list_item: avoid undefined behavior for empty list (ac7da78)
   1/*
   2 * "git reset" builtin command
   3 *
   4 * Copyright (c) 2007 Carlos Rica
   5 *
   6 * Based on git-reset.sh, which is
   7 *
   8 * Copyright (c) 2005, 2006 Linus Torvalds and Junio C Hamano
   9 */
  10#include "builtin.h"
  11#include "config.h"
  12#include "lockfile.h"
  13#include "tag.h"
  14#include "object.h"
  15#include "commit.h"
  16#include "run-command.h"
  17#include "refs.h"
  18#include "diff.h"
  19#include "diffcore.h"
  20#include "tree.h"
  21#include "branch.h"
  22#include "parse-options.h"
  23#include "unpack-trees.h"
  24#include "cache-tree.h"
  25#include "submodule.h"
  26#include "submodule-config.h"
  27
  28static const char * const git_reset_usage[] = {
  29        N_("git reset [--mixed | --soft | --hard | --merge | --keep] [-q] [<commit>]"),
  30        N_("git reset [-q] [<tree-ish>] [--] <paths>..."),
  31        N_("git reset --patch [<tree-ish>] [--] [<paths>...]"),
  32        NULL
  33};
  34
  35enum reset_type { MIXED, SOFT, HARD, MERGE, KEEP, NONE };
  36static const char *reset_type_names[] = {
  37        N_("mixed"), N_("soft"), N_("hard"), N_("merge"), N_("keep"), NULL
  38};
  39
  40static inline int is_merge(void)
  41{
  42        return !access(git_path_merge_head(), F_OK);
  43}
  44
  45static int reset_index(const struct object_id *oid, int reset_type, int quiet)
  46{
  47        int nr = 1;
  48        struct tree_desc desc[2];
  49        struct tree *tree;
  50        struct unpack_trees_options opts;
  51
  52        memset(&opts, 0, sizeof(opts));
  53        opts.head_idx = 1;
  54        opts.src_index = &the_index;
  55        opts.dst_index = &the_index;
  56        opts.fn = oneway_merge;
  57        opts.merge = 1;
  58        if (!quiet)
  59                opts.verbose_update = 1;
  60        switch (reset_type) {
  61        case KEEP:
  62        case MERGE:
  63                opts.update = 1;
  64                break;
  65        case HARD:
  66                opts.update = 1;
  67                /* fallthrough */
  68        default:
  69                opts.reset = 1;
  70        }
  71
  72        read_cache_unmerged();
  73
  74        if (reset_type == KEEP) {
  75                struct object_id head_oid;
  76                if (get_oid("HEAD", &head_oid))
  77                        return error(_("You do not have a valid HEAD."));
  78                if (!fill_tree_descriptor(desc, head_oid.hash))
  79                        return error(_("Failed to find tree of HEAD."));
  80                nr++;
  81                opts.fn = twoway_merge;
  82        }
  83
  84        if (!fill_tree_descriptor(desc + nr - 1, oid->hash))
  85                return error(_("Failed to find tree of %s."), oid_to_hex(oid));
  86        if (unpack_trees(nr, desc, &opts))
  87                return -1;
  88
  89        if (reset_type == MIXED || reset_type == HARD) {
  90                tree = parse_tree_indirect(oid);
  91                prime_cache_tree(&the_index, tree);
  92        }
  93
  94        return 0;
  95}
  96
  97static void print_new_head_line(struct commit *commit)
  98{
  99        const char *hex, *body;
 100        const char *msg;
 101
 102        hex = find_unique_abbrev(commit->object.oid.hash, DEFAULT_ABBREV);
 103        printf(_("HEAD is now at %s"), hex);
 104        msg = logmsg_reencode(commit, NULL, get_log_output_encoding());
 105        body = strstr(msg, "\n\n");
 106        if (body) {
 107                const char *eol;
 108                size_t len;
 109                body = skip_blank_lines(body + 2);
 110                eol = strchr(body, '\n');
 111                len = eol ? eol - body : strlen(body);
 112                printf(" %.*s\n", (int) len, body);
 113        }
 114        else
 115                printf("\n");
 116        unuse_commit_buffer(commit, msg);
 117}
 118
 119static void update_index_from_diff(struct diff_queue_struct *q,
 120                struct diff_options *opt, void *data)
 121{
 122        int i;
 123        int intent_to_add = *(int *)data;
 124
 125        for (i = 0; i < q->nr; i++) {
 126                struct diff_filespec *one = q->queue[i]->one;
 127                int is_missing = !(one->mode && !is_null_oid(&one->oid));
 128                struct cache_entry *ce;
 129
 130                if (is_missing && !intent_to_add) {
 131                        remove_file_from_cache(one->path);
 132                        continue;
 133                }
 134
 135                ce = make_cache_entry(one->mode, one->oid.hash, one->path,
 136                                      0, 0);
 137                if (!ce)
 138                        die(_("make_cache_entry failed for path '%s'"),
 139                            one->path);
 140                if (is_missing) {
 141                        ce->ce_flags |= CE_INTENT_TO_ADD;
 142                        set_object_name_for_intent_to_add_entry(ce);
 143                }
 144                add_cache_entry(ce, ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
 145        }
 146}
 147
 148static int read_from_tree(const struct pathspec *pathspec,
 149                          struct object_id *tree_oid,
 150                          int intent_to_add)
 151{
 152        struct diff_options opt;
 153
 154        memset(&opt, 0, sizeof(opt));
 155        copy_pathspec(&opt.pathspec, pathspec);
 156        opt.output_format = DIFF_FORMAT_CALLBACK;
 157        opt.format_callback = update_index_from_diff;
 158        opt.format_callback_data = &intent_to_add;
 159
 160        if (do_diff_cache(tree_oid, &opt))
 161                return 1;
 162        diffcore_std(&opt);
 163        diff_flush(&opt);
 164        clear_pathspec(&opt.pathspec);
 165
 166        return 0;
 167}
 168
 169static void set_reflog_message(struct strbuf *sb, const char *action,
 170                               const char *rev)
 171{
 172        const char *rla = getenv("GIT_REFLOG_ACTION");
 173
 174        strbuf_reset(sb);
 175        if (rla)
 176                strbuf_addf(sb, "%s: %s", rla, action);
 177        else if (rev)
 178                strbuf_addf(sb, "reset: moving to %s", rev);
 179        else
 180                strbuf_addf(sb, "reset: %s", action);
 181}
 182
 183static void die_if_unmerged_cache(int reset_type)
 184{
 185        if (is_merge() || unmerged_cache())
 186                die(_("Cannot do a %s reset in the middle of a merge."),
 187                    _(reset_type_names[reset_type]));
 188
 189}
 190
 191static void parse_args(struct pathspec *pathspec,
 192                       const char **argv, const char *prefix,
 193                       int patch_mode,
 194                       const char **rev_ret)
 195{
 196        const char *rev = "HEAD";
 197        struct object_id unused;
 198        /*
 199         * Possible arguments are:
 200         *
 201         * git reset [-opts] [<rev>]
 202         * git reset [-opts] <tree> [<paths>...]
 203         * git reset [-opts] <tree> -- [<paths>...]
 204         * git reset [-opts] -- [<paths>...]
 205         * git reset [-opts] <paths>...
 206         *
 207         * At this point, argv points immediately after [-opts].
 208         */
 209
 210        if (argv[0]) {
 211                if (!strcmp(argv[0], "--")) {
 212                        argv++; /* reset to HEAD, possibly with paths */
 213                } else if (argv[1] && !strcmp(argv[1], "--")) {
 214                        rev = argv[0];
 215                        argv += 2;
 216                }
 217                /*
 218                 * Otherwise, argv[0] could be either <rev> or <paths> and
 219                 * has to be unambiguous. If there is a single argument, it
 220                 * can not be a tree
 221                 */
 222                else if ((!argv[1] && !get_sha1_committish(argv[0], unused.hash)) ||
 223                         (argv[1] && !get_sha1_treeish(argv[0], unused.hash))) {
 224                        /*
 225                         * Ok, argv[0] looks like a commit/tree; it should not
 226                         * be a filename.
 227                         */
 228                        verify_non_filename(prefix, argv[0]);
 229                        rev = *argv++;
 230                } else {
 231                        /* Otherwise we treat this as a filename */
 232                        verify_filename(prefix, argv[0], 1);
 233                }
 234        }
 235        *rev_ret = rev;
 236
 237        if (read_cache() < 0)
 238                die(_("index file corrupt"));
 239
 240        parse_pathspec(pathspec, 0,
 241                       PATHSPEC_PREFER_FULL |
 242                       (patch_mode ? PATHSPEC_PREFIX_ORIGIN : 0),
 243                       prefix, argv);
 244}
 245
 246static int reset_refs(const char *rev, const struct object_id *oid)
 247{
 248        int update_ref_status;
 249        struct strbuf msg = STRBUF_INIT;
 250        struct object_id *orig = NULL, oid_orig,
 251                *old_orig = NULL, oid_old_orig;
 252
 253        if (!get_oid("ORIG_HEAD", &oid_old_orig))
 254                old_orig = &oid_old_orig;
 255        if (!get_oid("HEAD", &oid_orig)) {
 256                orig = &oid_orig;
 257                set_reflog_message(&msg, "updating ORIG_HEAD", NULL);
 258                update_ref_oid(msg.buf, "ORIG_HEAD", orig, old_orig, 0,
 259                           UPDATE_REFS_MSG_ON_ERR);
 260        } else if (old_orig)
 261                delete_ref(NULL, "ORIG_HEAD", old_orig->hash, 0);
 262        set_reflog_message(&msg, "updating HEAD", rev);
 263        update_ref_status = update_ref_oid(msg.buf, "HEAD", oid, orig, 0,
 264                                       UPDATE_REFS_MSG_ON_ERR);
 265        strbuf_release(&msg);
 266        return update_ref_status;
 267}
 268
 269static int git_reset_config(const char *var, const char *value, void *cb)
 270{
 271        if (!strcmp(var, "submodule.recurse"))
 272                return git_default_submodule_config(var, value, cb);
 273
 274        return git_default_config(var, value, cb);
 275}
 276
 277int cmd_reset(int argc, const char **argv, const char *prefix)
 278{
 279        int reset_type = NONE, update_ref_status = 0, quiet = 0;
 280        int patch_mode = 0, unborn;
 281        const char *rev;
 282        struct object_id oid;
 283        struct pathspec pathspec;
 284        int intent_to_add = 0;
 285        const struct option options[] = {
 286                OPT__QUIET(&quiet, N_("be quiet, only report errors")),
 287                OPT_SET_INT(0, "mixed", &reset_type,
 288                                                N_("reset HEAD and index"), MIXED),
 289                OPT_SET_INT(0, "soft", &reset_type, N_("reset only HEAD"), SOFT),
 290                OPT_SET_INT(0, "hard", &reset_type,
 291                                N_("reset HEAD, index and working tree"), HARD),
 292                OPT_SET_INT(0, "merge", &reset_type,
 293                                N_("reset HEAD, index and working tree"), MERGE),
 294                OPT_SET_INT(0, "keep", &reset_type,
 295                                N_("reset HEAD but keep local changes"), KEEP),
 296                { OPTION_CALLBACK, 0, "recurse-submodules", NULL,
 297                            "reset", "control recursive updating of submodules",
 298                            PARSE_OPT_OPTARG, option_parse_recurse_submodules_worktree_updater },
 299                OPT_BOOL('p', "patch", &patch_mode, N_("select hunks interactively")),
 300                OPT_BOOL('N', "intent-to-add", &intent_to_add,
 301                                N_("record only the fact that removed paths will be added later")),
 302                OPT_END()
 303        };
 304
 305        git_config(git_reset_config, NULL);
 306
 307        argc = parse_options(argc, argv, prefix, options, git_reset_usage,
 308                                                PARSE_OPT_KEEP_DASHDASH);
 309        parse_args(&pathspec, argv, prefix, patch_mode, &rev);
 310
 311        load_submodule_cache();
 312
 313        unborn = !strcmp(rev, "HEAD") && get_sha1("HEAD", oid.hash);
 314        if (unborn) {
 315                /* reset on unborn branch: treat as reset to empty tree */
 316                hashcpy(oid.hash, EMPTY_TREE_SHA1_BIN);
 317        } else if (!pathspec.nr) {
 318                struct commit *commit;
 319                if (get_sha1_committish(rev, oid.hash))
 320                        die(_("Failed to resolve '%s' as a valid revision."), rev);
 321                commit = lookup_commit_reference(&oid);
 322                if (!commit)
 323                        die(_("Could not parse object '%s'."), rev);
 324                oidcpy(&oid, &commit->object.oid);
 325        } else {
 326                struct tree *tree;
 327                if (get_sha1_treeish(rev, oid.hash))
 328                        die(_("Failed to resolve '%s' as a valid tree."), rev);
 329                tree = parse_tree_indirect(&oid);
 330                if (!tree)
 331                        die(_("Could not parse object '%s'."), rev);
 332                oidcpy(&oid, &tree->object.oid);
 333        }
 334
 335        if (patch_mode) {
 336                if (reset_type != NONE)
 337                        die(_("--patch is incompatible with --{hard,mixed,soft}"));
 338                return run_add_interactive(rev, "--patch=reset", &pathspec);
 339        }
 340
 341        /* git reset tree [--] paths... can be used to
 342         * load chosen paths from the tree into the index without
 343         * affecting the working tree nor HEAD. */
 344        if (pathspec.nr) {
 345                if (reset_type == MIXED)
 346                        warning(_("--mixed with paths is deprecated; use 'git reset -- <paths>' instead."));
 347                else if (reset_type != NONE)
 348                        die(_("Cannot do %s reset with paths."),
 349                                        _(reset_type_names[reset_type]));
 350        }
 351        if (reset_type == NONE)
 352                reset_type = MIXED; /* by default */
 353
 354        if (reset_type != SOFT && (reset_type != MIXED || get_git_work_tree()))
 355                setup_work_tree();
 356
 357        if (reset_type == MIXED && is_bare_repository())
 358                die(_("%s reset is not allowed in a bare repository"),
 359                    _(reset_type_names[reset_type]));
 360
 361        if (intent_to_add && reset_type != MIXED)
 362                die(_("-N can only be used with --mixed"));
 363
 364        /* Soft reset does not touch the index file nor the working tree
 365         * at all, but requires them in a good order.  Other resets reset
 366         * the index file to the tree object we are switching to. */
 367        if (reset_type == SOFT || reset_type == KEEP)
 368                die_if_unmerged_cache(reset_type);
 369
 370        if (reset_type != SOFT) {
 371                struct lock_file *lock = xcalloc(1, sizeof(*lock));
 372                hold_locked_index(lock, LOCK_DIE_ON_ERROR);
 373                if (reset_type == MIXED) {
 374                        int flags = quiet ? REFRESH_QUIET : REFRESH_IN_PORCELAIN;
 375                        if (read_from_tree(&pathspec, &oid, intent_to_add))
 376                                return 1;
 377                        if (get_git_work_tree())
 378                                refresh_index(&the_index, flags, NULL, NULL,
 379                                              _("Unstaged changes after reset:"));
 380                } else {
 381                        int err = reset_index(&oid, reset_type, quiet);
 382                        if (reset_type == KEEP && !err)
 383                                err = reset_index(&oid, MIXED, quiet);
 384                        if (err)
 385                                die(_("Could not reset index file to revision '%s'."), rev);
 386                }
 387
 388                if (write_locked_index(&the_index, lock, COMMIT_LOCK))
 389                        die(_("Could not write new index file."));
 390        }
 391
 392        if (!pathspec.nr && !unborn) {
 393                /* Any resets without paths update HEAD to the head being
 394                 * switched to, saving the previous head in ORIG_HEAD before. */
 395                update_ref_status = reset_refs(rev, &oid);
 396
 397                if (reset_type == HARD && !update_ref_status && !quiet)
 398                        print_new_head_line(lookup_commit_reference(&oid));
 399        }
 400        if (!pathspec.nr)
 401                remove_branch_state();
 402
 403        return update_ref_status;
 404}