builtin/reset.c

   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 "tag.h"
  12 #include "object.h"
  13 #include "commit.h"
  14 #include "run-command.h"
  15 #include "refs.h"
  16 #include "diff.h"
  17 #include "diffcore.h"
  18 #include "tree.h"
  19 #include "branch.h"
  20 #include "parse-options.h"
  21 #include "unpack-trees.h"
  22 #include "cache-tree.h"
  23
  24 static const char * const git_reset_usage[] = {
  25         N_("git reset [--mixed | --soft | --hard | --merge | --keep] [-q] [<commit>]"),
  26         N_("git reset [-q] <commit> [--] <paths>..."),
  27         N_("git reset --patch [<commit>] [--] [<paths>...]"),
  28         NULL
  29 };
  30
  31 enum reset_type { MIXED, SOFT, HARD, MERGE, KEEP, NONE };
  32 static const char *reset_type_names[] = {
  33         N_("mixed"), N_("soft"), N_("hard"), N_("merge"), N_("keep"), NULL
  34 };
  35
  36 static inline int is_merge(void)
  37 {
  38         return !access(git_path("MERGE_HEAD"), F_OK);
  39 }
  40
  41 static int reset_index_file(const unsigned char *sha1, int reset_type, int quiet)
  42 {
  43         int nr = 1;
  44         int newfd;
  45         struct tree_desc desc[2];
  46         struct tree *tree;
  47         struct unpack_trees_options opts;
  48         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
  49
  50         memset(&opts, 0, sizeof(opts));
  51         opts.head_idx = 1;
  52         opts.src_index = &the_index;
  53         opts.dst_index = &the_index;
  54         opts.fn = oneway_merge;
  55         opts.merge = 1;
  56         if (!quiet)
  57                 opts.verbose_update = 1;
  58         switch (reset_type) {
  59         case KEEP:
  60         case MERGE:
  61                 opts.update = 1;
  62                 break;
  63         case HARD:
  64                 opts.update = 1;
  65                 /* fallthrough */
  66         default:
  67                 opts.reset = 1;
  68         }
  69
  70         newfd = hold_locked_index(lock, 1);
  71
  72         read_cache_unmerged();
  73
  74         if (reset_type == KEEP) {
  75                 unsigned char head_sha1[20];
  76                 if (get_sha1("HEAD", head_sha1))
  77                         return error(_("You do not have a valid HEAD."));
  78                 if (!fill_tree_descriptor(desc, head_sha1))
  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, sha1))
  85                 return error(_("Failed to find tree of %s."), sha1_to_hex(sha1));
  86         if (unpack_trees(nr, desc, &opts))
  87                 return -1;
  88
  89         if (reset_type == MIXED || reset_type == HARD) {
  90                 tree = parse_tree_indirect(sha1);
  91                 prime_cache_tree(&active_cache_tree, tree);
  92         }
  93
  94         if (write_cache(newfd, active_cache, active_nr) ||
  95             commit_locked_index(lock))
  96                 return error(_("Could not write new index file."));
  97
  98         return 0;
  99 }
 100
 101 static void print_new_head_line(struct commit *commit)
 102 {
 103         const char *hex, *body;
 104
 105         hex = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
 106         printf(_("HEAD is now at %s"), hex);
 107         body = strstr(commit->buffer, "\n\n");
 108         if (body) {
 109                 const char *eol;
 110                 size_t len;
 111                 body += 2;
 112                 eol = strchr(body, '\n');
 113                 len = eol ? eol - body : strlen(body);
 114                 printf(" %.*s\n", (int) len, body);
 115         }
 116         else
 117                 printf("\n");
 118 }
 119
 120 static int update_index_refresh(int fd, struct lock_file *index_lock, int flags)
 121 {
 122         int result;
 123
 124         if (!index_lock) {
 125                 index_lock = xcalloc(1, sizeof(struct lock_file));
 126                 fd = hold_locked_index(index_lock, 1);
 127         }
 128
 129         if (read_cache() < 0)
 130                 return error(_("Could not read index"));
 131
 132         result = refresh_index(&the_index, (flags), NULL, NULL,
 133                                _("Unstaged changes after reset:")) ? 1 : 0;
 134         if (write_cache(fd, active_cache, active_nr) ||
 135                         commit_locked_index(index_lock))
 136                 return error ("Could not refresh index");
 137         return result;
 138 }
 139
 140 static void update_index_from_diff(struct diff_queue_struct *q,
 141                 struct diff_options *opt, void *data)
 142 {
 143         int i;
 144         int *discard_flag = data;
 145
 146         /* do_diff_cache() mangled the index */
 147         discard_cache();
 148         *discard_flag = 1;
 149         read_cache();
 150
 151         for (i = 0; i < q->nr; i++) {
 152                 struct diff_filespec *one = q->queue[i]->one;
 153                 if (one->mode && !is_null_sha1(one->sha1)) {
 154                         struct cache_entry *ce;
 155                         ce = make_cache_entry(one->mode, one->sha1, one->path,
 156                                 0, 0);
 157                         if (!ce)
 158                                 die(_("make_cache_entry failed for path '%s'"),
 159                                     one->path);
 160                         add_cache_entry(ce, ADD_CACHE_OK_TO_ADD |
 161                                 ADD_CACHE_OK_TO_REPLACE);
 162                 } else
 163                         remove_file_from_cache(one->path);
 164         }
 165 }
 166
 167 static int interactive_reset(const char *revision, const char **argv,
 168                              const char *prefix)
 169 {
 170         const char **pathspec = NULL;
 171
 172         if (*argv)
 173                 pathspec = get_pathspec(prefix, argv);
 174
 175         return run_add_interactive(revision, "--patch=reset", pathspec);
 176 }
 177
 178 static int read_from_tree(const char *prefix, const char **argv,
 179                 unsigned char *tree_sha1, int refresh_flags)
 180 {
 181         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
 182         int index_fd, index_was_discarded = 0;
 183         struct diff_options opt;
 184
 185         memset(&opt, 0, sizeof(opt));
 186         diff_tree_setup_paths(get_pathspec(prefix, (const char **)argv), &opt);
 187         opt.output_format = DIFF_FORMAT_CALLBACK;
 188         opt.format_callback = update_index_from_diff;
 189         opt.format_callback_data = &index_was_discarded;
 190
 191         index_fd = hold_locked_index(lock, 1);
 192         index_was_discarded = 0;
 193         read_cache();
 194         if (do_diff_cache(tree_sha1, &opt))
 195                 return 1;
 196         diffcore_std(&opt);
 197         diff_flush(&opt);
 198         diff_tree_release_paths(&opt);
 199
 200         if (!index_was_discarded)
 201                 /* The index is still clobbered from do_diff_cache() */
 202                 discard_cache();
 203         return update_index_refresh(index_fd, lock, refresh_flags);
 204 }
 205
 206 static void set_reflog_message(struct strbuf *sb, const char *action,
 207                                const char *rev)
 208 {
 209         const char *rla = getenv("GIT_REFLOG_ACTION");
 210
 211         strbuf_reset(sb);
 212         if (rla)
 213                 strbuf_addf(sb, "%s: %s", rla, action);
 214         else if (rev)
 215                 strbuf_addf(sb, "reset: moving to %s", rev);
 216         else
 217                 strbuf_addf(sb, "reset: %s", action);
 218 }
 219
 220 static void die_if_unmerged_cache(int reset_type)
 221 {
 222         if (is_merge() || read_cache() < 0 || unmerged_cache())
 223                 die(_("Cannot do a %s reset in the middle of a merge."),
 224                     _(reset_type_names[reset_type]));
 225
 226 }
 227
 228 int cmd_reset(int argc, const char **argv, const char *prefix)
 229 {
 230         int i = 0, reset_type = NONE, update_ref_status = 0, quiet = 0;
 231         int patch_mode = 0;
 232         const char *rev = "HEAD";
 233         unsigned char sha1[20], *orig = NULL, sha1_orig[20],
 234                                 *old_orig = NULL, sha1_old_orig[20];
 235         struct commit *commit;
 236         struct strbuf msg = STRBUF_INIT;
 237         const struct option options[] = {
 238                 OPT__QUIET(&quiet, N_("be quiet, only report errors")),
 239                 OPT_SET_INT(0, "mixed", &reset_type,
 240                                                 N_("reset HEAD and index"), MIXED),
 241                 OPT_SET_INT(0, "soft", &reset_type, N_("reset only HEAD"), SOFT),
 242                 OPT_SET_INT(0, "hard", &reset_type,
 243                                 N_("reset HEAD, index and working tree"), HARD),
 244                 OPT_SET_INT(0, "merge", &reset_type,
 245                                 N_("reset HEAD, index and working tree"), MERGE),
 246                 OPT_SET_INT(0, "keep", &reset_type,
 247                                 N_("reset HEAD but keep local changes"), KEEP),
 248                 OPT_BOOLEAN('p', "patch", &patch_mode, N_("select hunks interactively")),
 249                 OPT_END()
 250         };
 251
 252         git_config(git_default_config, NULL);
 253
 254         argc = parse_options(argc, argv, prefix, options, git_reset_usage,
 255                                                 PARSE_OPT_KEEP_DASHDASH);
 256
 257         /*
 258          * Possible arguments are:
 259          *
 260          * git reset [-opts] <rev> <paths>...
 261          * git reset [-opts] <rev> -- <paths>...
 262          * git reset [-opts] -- <paths>...
 263          * git reset [-opts] <paths>...
 264          *
 265          * At this point, argv[i] points immediately after [-opts].
 266          */
 267
 268         if (i < argc) {
 269                 if (!strcmp(argv[i], "--")) {
 270                         i++; /* reset to HEAD, possibly with paths */
 271                 } else if (i + 1 < argc && !strcmp(argv[i+1], "--")) {
 272                         rev = argv[i];
 273                         i += 2;
 274                 }
 275                 /*
 276                  * Otherwise, argv[i] could be either <rev> or <paths> and
 277                  * has to be unambiguous.
 278                  */
 279                 else if (!get_sha1_committish(argv[i], sha1)) {
 280                         /*
 281                          * Ok, argv[i] looks like a rev; it should not
 282                          * be a filename.
 283                          */
 284                         verify_non_filename(prefix, argv[i]);
 285                         rev = argv[i++];
 286                 } else {
 287                         /* Otherwise we treat this as a filename */
 288                         verify_filename(prefix, argv[i], 1);
 289                 }
 290         }
 291
 292         if (get_sha1_committish(rev, sha1))
 293                 die(_("Failed to resolve '%s' as a valid ref."), rev);
 294
 295         /*
 296          * NOTE: As "git reset $treeish -- $path" should be usable on
 297          * any tree-ish, this is not strictly correct. We are not
 298          * moving the HEAD to any commit; we are merely resetting the
 299          * entries in the index to that of a treeish.
 300          */
 301         commit = lookup_commit_reference(sha1);
 302         if (!commit)
 303                 die(_("Could not parse object '%s'."), rev);
 304         hashcpy(sha1, commit->object.sha1);
 305
 306         if (patch_mode) {
 307                 if (reset_type != NONE)
 308                         die(_("--patch is incompatible with --{hard,mixed,soft}"));
 309                 return interactive_reset(rev, argv + i, prefix);
 310         }
 311
 312         /* git reset tree [--] paths... can be used to
 313          * load chosen paths from the tree into the index without
 314          * affecting the working tree nor HEAD. */
 315         if (i < argc) {
 316                 if (reset_type == MIXED)
 317                         warning(_("--mixed with paths is deprecated; use 'git reset -- <paths>' instead."));
 318                 else if (reset_type != NONE)
 319                         die(_("Cannot do %s reset with paths."),
 320                                         _(reset_type_names[reset_type]));
 321                 return read_from_tree(prefix, argv + i, sha1,
 322                                 quiet ? REFRESH_QUIET : REFRESH_IN_PORCELAIN);
 323         }
 324         if (reset_type == NONE)
 325                 reset_type = MIXED; /* by default */
 326
 327         if (reset_type != SOFT && reset_type != MIXED)
 328                 setup_work_tree();
 329
 330         if (reset_type == MIXED && is_bare_repository())
 331                 die(_("%s reset is not allowed in a bare repository"),
 332                     _(reset_type_names[reset_type]));
 333
 334         /* Soft reset does not touch the index file nor the working tree
 335          * at all, but requires them in a good order.  Other resets reset
 336          * the index file to the tree object we are switching to. */
 337         if (reset_type == SOFT)
 338                 die_if_unmerged_cache(reset_type);
 339         else {
 340                 int err;
 341                 if (reset_type == KEEP)
 342                         die_if_unmerged_cache(reset_type);
 343                 err = reset_index_file(sha1, reset_type, quiet);
 344                 if (reset_type == KEEP)
 345                         err = err || reset_index_file(sha1, MIXED, quiet);
 346                 if (err)
 347                         die(_("Could not reset index file to revision '%s'."), rev);
 348         }
 349
 350         /* Any resets update HEAD to the head being switched to,
 351          * saving the previous head in ORIG_HEAD before. */
 352         if (!get_sha1("ORIG_HEAD", sha1_old_orig))
 353                 old_orig = sha1_old_orig;
 354         if (!get_sha1("HEAD", sha1_orig)) {
 355                 orig = sha1_orig;
 356                 set_reflog_message(&msg, "updating ORIG_HEAD", NULL);
 357                 update_ref(msg.buf, "ORIG_HEAD", orig, old_orig, 0, MSG_ON_ERR);
 358         }
 359         else if (old_orig)
 360                 delete_ref("ORIG_HEAD", old_orig, 0);
 361         set_reflog_message(&msg, "updating HEAD", rev);
 362         update_ref_status = update_ref(msg.buf, "HEAD", sha1, orig, 0, MSG_ON_ERR);
 363
 364         switch (reset_type) {
 365         case HARD:
 366                 if (!update_ref_status && !quiet)
 367                         print_new_head_line(commit);
 368                 break;
 369         case SOFT: /* Nothing else to do. */
 370                 break;
 371         case MIXED: /* Report what has not been updated. */
 372                 update_index_refresh(0, NULL,
 373                                 quiet ? REFRESH_QUIET : REFRESH_IN_PORCELAIN);
 374                 break;
 375         }
 376
 377         remove_branch_state();
 378
 379         strbuf_release(&msg);
 380
 381         return update_ref_status;
 382 }