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         "git reset [--mixed | --soft | --hard | --merge | --keep] [-q] [<commit>]",
  26         "git reset [-q] <commit> [--] <paths>...",
  27         "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 unpack_trees_options opts;
  47         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
  48
  49         memset(&opts, 0, sizeof(opts));
  50         opts.head_idx = 1;
  51         opts.src_index = &the_index;
  52         opts.dst_index = &the_index;
  53         opts.fn = oneway_merge;
  54         opts.merge = 1;
  55         if (!quiet)
  56                 opts.verbose_update = 1;
  57         switch (reset_type) {
  58         case KEEP:
  59         case MERGE:
  60                 opts.update = 1;
  61                 break;
  62         case HARD:
  63                 opts.update = 1;
  64                 /* fallthrough */
  65         default:
  66                 opts.reset = 1;
  67         }
  68
  69         newfd = hold_locked_index(lock, 1);
  70
  71         read_cache_unmerged();
  72
  73         if (reset_type == KEEP) {
  74                 unsigned char head_sha1[20];
  75                 if (get_sha1("HEAD", head_sha1))
  76                         return error(_("You do not have a valid HEAD."));
  77                 if (!fill_tree_descriptor(desc, head_sha1))
  78                         return error(_("Failed to find tree of HEAD."));
  79                 nr++;
  80                 opts.fn = twoway_merge;
  81         }
  82
  83         if (!fill_tree_descriptor(desc + nr - 1, sha1))
  84                 return error(_("Failed to find tree of %s."), sha1_to_hex(sha1));
  85         if (unpack_trees(nr, desc, &opts))
  86                 return -1;
  87         if (write_cache(newfd, active_cache, active_nr) ||
  88             commit_locked_index(lock))
  89                 return error(_("Could not write new index file."));
  90
  91         return 0;
  92 }
  93
  94 static void print_new_head_line(struct commit *commit)
  95 {
  96         const char *hex, *body;
  97
  98         hex = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
  99         printf(_("HEAD is now at %s"), hex);
 100         body = strstr(commit->buffer, "\n\n");
 101         if (body) {
 102                 const char *eol;
 103                 size_t len;
 104                 body += 2;
 105                 eol = strchr(body, '\n');
 106                 len = eol ? eol - body : strlen(body);
 107                 printf(" %.*s\n", (int) len, body);
 108         }
 109         else
 110                 printf("\n");
 111 }
 112
 113 static int update_index_refresh(int fd, struct lock_file *index_lock, int flags)
 114 {
 115         int result;
 116
 117         if (!index_lock) {
 118                 index_lock = xcalloc(1, sizeof(struct lock_file));
 119                 fd = hold_locked_index(index_lock, 1);
 120         }
 121
 122         if (read_cache() < 0)
 123                 return error(_("Could not read index"));
 124
 125         result = refresh_index(&the_index, (flags), NULL, NULL,
 126                                _("Unstaged changes after reset:")) ? 1 : 0;
 127         if (write_cache(fd, active_cache, active_nr) ||
 128                         commit_locked_index(index_lock))
 129                 return error ("Could not refresh index");
 130         return result;
 131 }
 132
 133 static void update_index_from_diff(struct diff_queue_struct *q,
 134                 struct diff_options *opt, void *data)
 135 {
 136         int i;
 137         int *discard_flag = data;
 138
 139         /* do_diff_cache() mangled the index */
 140         discard_cache();
 141         *discard_flag = 1;
 142         read_cache();
 143
 144         for (i = 0; i < q->nr; i++) {
 145                 struct diff_filespec *one = q->queue[i]->one;
 146                 if (one->mode && !is_null_sha1(one->sha1)) {
 147                         struct cache_entry *ce;
 148                         ce = make_cache_entry(one->mode, one->sha1, one->path,
 149                                 0, 0);
 150                         if (!ce)
 151                                 die(_("make_cache_entry failed for path '%s'"),
 152                                     one->path);
 153                         add_cache_entry(ce, ADD_CACHE_OK_TO_ADD |
 154                                 ADD_CACHE_OK_TO_REPLACE);
 155                 } else
 156                         remove_file_from_cache(one->path);
 157         }
 158 }
 159
 160 static int interactive_reset(const char *revision, const char **argv,
 161                              const char *prefix)
 162 {
 163         const char **pathspec = NULL;
 164
 165         if (*argv)
 166                 pathspec = get_pathspec(prefix, argv);
 167
 168         return run_add_interactive(revision, "--patch=reset", pathspec);
 169 }
 170
 171 static int read_from_tree(const char *prefix, const char **argv,
 172                 unsigned char *tree_sha1, int refresh_flags)
 173 {
 174         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
 175         int index_fd, index_was_discarded = 0;
 176         struct diff_options opt;
 177
 178         memset(&opt, 0, sizeof(opt));
 179         diff_tree_setup_paths(get_pathspec(prefix, (const char **)argv), &opt);
 180         opt.output_format = DIFF_FORMAT_CALLBACK;
 181         opt.format_callback = update_index_from_diff;
 182         opt.format_callback_data = &index_was_discarded;
 183
 184         index_fd = hold_locked_index(lock, 1);
 185         index_was_discarded = 0;
 186         read_cache();
 187         if (do_diff_cache(tree_sha1, &opt))
 188                 return 1;
 189         diffcore_std(&opt);
 190         diff_flush(&opt);
 191         diff_tree_release_paths(&opt);
 192
 193         if (!index_was_discarded)
 194                 /* The index is still clobbered from do_diff_cache() */
 195                 discard_cache();
 196         return update_index_refresh(index_fd, lock, refresh_flags);
 197 }
 198
 199 static void set_reflog_message(struct strbuf *sb, const char *action,
 200                                const char *rev)
 201 {
 202         const char *rla = getenv("GIT_REFLOG_ACTION");
 203
 204         strbuf_reset(sb);
 205         if (rla)
 206                 strbuf_addf(sb, "%s: %s", rla, action);
 207         else if (rev)
 208                 strbuf_addf(sb, "reset: moving to %s", rev);
 209         else
 210                 strbuf_addf(sb, "reset: %s", action);
 211 }
 212
 213 static void die_if_unmerged_cache(int reset_type)
 214 {
 215         if (is_merge() || read_cache() < 0 || unmerged_cache())
 216                 die(_("Cannot do a %s reset in the middle of a merge."),
 217                     _(reset_type_names[reset_type]));
 218
 219 }
 220
 221 int cmd_reset(int argc, const char **argv, const char *prefix)
 222 {
 223         int i = 0, reset_type = NONE, update_ref_status = 0, quiet = 0;
 224         int patch_mode = 0;
 225         const char *rev = "HEAD";
 226         unsigned char sha1[20], *orig = NULL, sha1_orig[20],
 227                                 *old_orig = NULL, sha1_old_orig[20];
 228         struct commit *commit;
 229         struct strbuf msg = STRBUF_INIT;
 230         const struct option options[] = {
 231                 OPT__QUIET(&quiet, "be quiet, only report errors"),
 232                 OPT_SET_INT(0, "mixed", &reset_type,
 233                                                 "reset HEAD and index", MIXED),
 234                 OPT_SET_INT(0, "soft", &reset_type, "reset only HEAD", SOFT),
 235                 OPT_SET_INT(0, "hard", &reset_type,
 236                                 "reset HEAD, index and working tree", HARD),
 237                 OPT_SET_INT(0, "merge", &reset_type,
 238                                 "reset HEAD, index and working tree", MERGE),
 239                 OPT_SET_INT(0, "keep", &reset_type,
 240                                 "reset HEAD but keep local changes", KEEP),
 241                 OPT_BOOLEAN('p', "patch", &patch_mode, "select hunks interactively"),
 242                 OPT_END()
 243         };
 244
 245         git_config(git_default_config, NULL);
 246
 247         argc = parse_options(argc, argv, prefix, options, git_reset_usage,
 248                                                 PARSE_OPT_KEEP_DASHDASH);
 249
 250         /*
 251          * Possible arguments are:
 252          *
 253          * git reset [-opts] <rev> <paths>...
 254          * git reset [-opts] <rev> -- <paths>...
 255          * git reset [-opts] -- <paths>...
 256          * git reset [-opts] <paths>...
 257          *
 258          * At this point, argv[i] points immediately after [-opts].
 259          */
 260
 261         if (i < argc) {
 262                 if (!strcmp(argv[i], "--")) {
 263                         i++; /* reset to HEAD, possibly with paths */
 264                 } else if (i + 1 < argc && !strcmp(argv[i+1], "--")) {
 265                         rev = argv[i];
 266                         i += 2;
 267                 }
 268                 /*
 269                  * Otherwise, argv[i] could be either <rev> or <paths> and
 270                  * has to be unambiguous.
 271                  */
 272                 else if (!get_sha1(argv[i], sha1)) {
 273                         /*
 274                          * Ok, argv[i] looks like a rev; it should not
 275                          * be a filename.
 276                          */
 277                         verify_non_filename(prefix, argv[i]);
 278                         rev = argv[i++];
 279                 } else {
 280                         /* Otherwise we treat this as a filename */
 281                         verify_filename(prefix, argv[i]);
 282                 }
 283         }
 284
 285         if (get_sha1(rev, sha1))
 286                 die(_("Failed to resolve '%s' as a valid ref."), rev);
 287
 288         commit = lookup_commit_reference(sha1);
 289         if (!commit)
 290                 die(_("Could not parse object '%s'."), rev);
 291         hashcpy(sha1, commit->object.sha1);
 292
 293         if (patch_mode) {
 294                 if (reset_type != NONE)
 295                         die(_("--patch is incompatible with --{hard,mixed,soft}"));
 296                 return interactive_reset(rev, argv + i, prefix);
 297         }
 298
 299         /* git reset tree [--] paths... can be used to
 300          * load chosen paths from the tree into the index without
 301          * affecting the working tree nor HEAD. */
 302         if (i < argc) {
 303                 if (reset_type == MIXED)
 304                         warning(_("--mixed with paths is deprecated; use 'git reset -- <paths>' instead."));
 305                 else if (reset_type != NONE)
 306                         die(_("Cannot do %s reset with paths."),
 307                                         _(reset_type_names[reset_type]));
 308                 return read_from_tree(prefix, argv + i, sha1,
 309                                 quiet ? REFRESH_QUIET : REFRESH_IN_PORCELAIN);
 310         }
 311         if (reset_type == NONE)
 312                 reset_type = MIXED; /* by default */
 313
 314         if (reset_type != SOFT && reset_type != MIXED)
 315                 setup_work_tree();
 316
 317         if (reset_type == MIXED && is_bare_repository())
 318                 die(_("%s reset is not allowed in a bare repository"),
 319                     _(reset_type_names[reset_type]));
 320
 321         /* Soft reset does not touch the index file nor the working tree
 322          * at all, but requires them in a good order.  Other resets reset
 323          * the index file to the tree object we are switching to. */
 324         if (reset_type == SOFT)
 325                 die_if_unmerged_cache(reset_type);
 326         else {
 327                 int err;
 328                 if (reset_type == KEEP)
 329                         die_if_unmerged_cache(reset_type);
 330                 err = reset_index_file(sha1, reset_type, quiet);
 331                 if (reset_type == KEEP)
 332                         err = err || reset_index_file(sha1, MIXED, quiet);
 333                 if (err)
 334                         die(_("Could not reset index file to revision '%s'."), rev);
 335         }
 336
 337         /* Any resets update HEAD to the head being switched to,
 338          * saving the previous head in ORIG_HEAD before. */
 339         if (!get_sha1("ORIG_HEAD", sha1_old_orig))
 340                 old_orig = sha1_old_orig;
 341         if (!get_sha1("HEAD", sha1_orig)) {
 342                 orig = sha1_orig;
 343                 set_reflog_message(&msg, "updating ORIG_HEAD", NULL);
 344                 update_ref(msg.buf, "ORIG_HEAD", orig, old_orig, 0, MSG_ON_ERR);
 345         }
 346         else if (old_orig)
 347                 delete_ref("ORIG_HEAD", old_orig, 0);
 348         set_reflog_message(&msg, "updating HEAD", rev);
 349         update_ref_status = update_ref(msg.buf, "HEAD", sha1, orig, 0, MSG_ON_ERR);
 350
 351         switch (reset_type) {
 352         case HARD:
 353                 if (!update_ref_status && !quiet)
 354                         print_new_head_line(commit);
 355                 break;
 356         case SOFT: /* Nothing else to do. */
 357                 break;
 358         case MIXED: /* Report what has not been updated. */
 359                 update_index_refresh(0, NULL,
 360                                 quiet ? REFRESH_QUIET : REFRESH_IN_PORCELAIN);
 361                 break;
 362         }
 363
 364         remove_branch_state();
 365
 366         strbuf_release(&msg);
 367
 368         return update_ref_status;
 369 }