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(const unsigned char *sha1, int reset_type, int quiet)
  42 {
  43         int nr = 1;
  44         struct tree_desc desc[2];
  45         struct tree *tree;
  46         struct unpack_trees_options opts;
  47
  48         memset(&opts, 0, sizeof(opts));
  49         opts.head_idx = 1;
  50         opts.src_index = &the_index;
  51         opts.dst_index = &the_index;
  52         opts.fn = oneway_merge;
  53         opts.merge = 1;
  54         if (!quiet)
  55                 opts.verbose_update = 1;
  56         switch (reset_type) {
  57         case KEEP:
  58         case MERGE:
  59                 opts.update = 1;
  60                 break;
  61         case HARD:
  62                 opts.update = 1;
  63                 /* fallthrough */
  64         default:
  65                 opts.reset = 1;
  66         }
  67
  68         read_cache_unmerged();
  69
  70         if (reset_type == KEEP) {
  71                 unsigned char head_sha1[20];
  72                 if (get_sha1("HEAD", head_sha1))
  73                         return error(_("You do not have a valid HEAD."));
  74                 if (!fill_tree_descriptor(desc, head_sha1))
  75                         return error(_("Failed to find tree of HEAD."));
  76                 nr++;
  77                 opts.fn = twoway_merge;
  78         }
  79
  80         if (!fill_tree_descriptor(desc + nr - 1, sha1))
  81                 return error(_("Failed to find tree of %s."), sha1_to_hex(sha1));
  82         if (unpack_trees(nr, desc, &opts))
  83                 return -1;
  84
  85         if (reset_type == MIXED || reset_type == HARD) {
  86                 tree = parse_tree_indirect(sha1);
  87                 prime_cache_tree(&active_cache_tree, tree);
  88         }
  89
  90         return 0;
  91 }
  92
  93 static void print_new_head_line(struct commit *commit)
  94 {
  95         const char *hex, *body;
  96
  97         hex = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
  98         printf(_("HEAD is now at %s"), hex);
  99         body = strstr(commit->buffer, "\n\n");
 100         if (body) {
 101                 const char *eol;
 102                 size_t len;
 103                 body += 2;
 104                 eol = strchr(body, '\n');
 105                 len = eol ? eol - body : strlen(body);
 106                 printf(" %.*s\n", (int) len, body);
 107         }
 108         else
 109                 printf("\n");
 110 }
 111
 112 static int update_index_refresh(int fd, struct lock_file *index_lock, int flags)
 113 {
 114         if (!index_lock) {
 115                 index_lock = xcalloc(1, sizeof(struct lock_file));
 116                 fd = hold_locked_index(index_lock, 1);
 117         }
 118
 119         refresh_index(&the_index, (flags), NULL, NULL,
 120                       _("Unstaged changes after reset:"));
 121         if (write_cache(fd, active_cache, active_nr) ||
 122                         commit_locked_index(index_lock))
 123                 return error ("Could not refresh index");
 124         return 0;
 125 }
 126
 127 static void update_index_from_diff(struct diff_queue_struct *q,
 128                 struct diff_options *opt, void *data)
 129 {
 130         int i;
 131
 132         for (i = 0; i < q->nr; i++) {
 133                 struct diff_filespec *one = q->queue[i]->one;
 134                 if (one->mode && !is_null_sha1(one->sha1)) {
 135                         struct cache_entry *ce;
 136                         ce = make_cache_entry(one->mode, one->sha1, one->path,
 137                                 0, 0);
 138                         if (!ce)
 139                                 die(_("make_cache_entry failed for path '%s'"),
 140                                     one->path);
 141                         add_cache_entry(ce, ADD_CACHE_OK_TO_ADD |
 142                                 ADD_CACHE_OK_TO_REPLACE);
 143                 } else
 144                         remove_file_from_cache(one->path);
 145         }
 146 }
 147
 148 static int read_from_tree(const char **pathspec, unsigned char *tree_sha1,
 149                           int refresh_flags)
 150 {
 151         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
 152         int index_fd;
 153         struct diff_options opt;
 154
 155         memset(&opt, 0, sizeof(opt));
 156         diff_tree_setup_paths(pathspec, &opt);
 157         opt.output_format = DIFF_FORMAT_CALLBACK;
 158         opt.format_callback = update_index_from_diff;
 159
 160         index_fd = hold_locked_index(lock, 1);
 161         read_cache();
 162         if (do_diff_cache(tree_sha1, &opt))
 163                 return 1;
 164         diffcore_std(&opt);
 165         diff_flush(&opt);
 166         diff_tree_release_paths(&opt);
 167
 168         return update_index_refresh(index_fd, lock, refresh_flags);
 169 }
 170
 171 static void set_reflog_message(struct strbuf *sb, const char *action,
 172                                const char *rev)
 173 {
 174         const char *rla = getenv("GIT_REFLOG_ACTION");
 175
 176         strbuf_reset(sb);
 177         if (rla)
 178                 strbuf_addf(sb, "%s: %s", rla, action);
 179         else if (rev)
 180                 strbuf_addf(sb, "reset: moving to %s", rev);
 181         else
 182                 strbuf_addf(sb, "reset: %s", action);
 183 }
 184
 185 static void die_if_unmerged_cache(int reset_type)
 186 {
 187         if (is_merge() || read_cache() < 0 || unmerged_cache())
 188                 die(_("Cannot do a %s reset in the middle of a merge."),
 189                     _(reset_type_names[reset_type]));
 190
 191 }
 192
 193 static const char **parse_args(const char **argv, const char *prefix, const char **rev_ret)
 194 {
 195         const char *rev = "HEAD";
 196         unsigned char unused[20];
 197         /*
 198          * Possible arguments are:
 199          *
 200          * git reset [-opts] <rev> <paths>...
 201          * git reset [-opts] <rev> -- <paths>...
 202          * git reset [-opts] -- <paths>...
 203          * git reset [-opts] <paths>...
 204          *
 205          * At this point, argv points immediately after [-opts].
 206          */
 207
 208         if (argv[0]) {
 209                 if (!strcmp(argv[0], "--")) {
 210                         argv++; /* reset to HEAD, possibly with paths */
 211                 } else if (argv[1] && !strcmp(argv[1], "--")) {
 212                         rev = argv[0];
 213                         argv += 2;
 214                 }
 215                 /*
 216                  * Otherwise, argv[0] could be either <rev> or <paths> and
 217                  * has to be unambiguous.
 218                  */
 219                 else if (!get_sha1_committish(argv[0], unused)) {
 220                         /*
 221                          * Ok, argv[0] looks like a rev; it should not
 222                          * be a filename.
 223                          */
 224                         verify_non_filename(prefix, argv[0]);
 225                         rev = *argv++;
 226                 } else {
 227                         /* Otherwise we treat this as a filename */
 228                         verify_filename(prefix, argv[0], 1);
 229                 }
 230         }
 231         *rev_ret = rev;
 232         return argv[0] ? get_pathspec(prefix, argv) : NULL;
 233 }
 234
 235 static int update_refs(const char *rev, const unsigned char *sha1)
 236 {
 237         int update_ref_status;
 238         struct strbuf msg = STRBUF_INIT;
 239         unsigned char *orig = NULL, sha1_orig[20],
 240                 *old_orig = NULL, sha1_old_orig[20];
 241
 242         if (!get_sha1("ORIG_HEAD", sha1_old_orig))
 243                 old_orig = sha1_old_orig;
 244         if (!get_sha1("HEAD", sha1_orig)) {
 245                 orig = sha1_orig;
 246                 set_reflog_message(&msg, "updating ORIG_HEAD", NULL);
 247                 update_ref(msg.buf, "ORIG_HEAD", orig, old_orig, 0, MSG_ON_ERR);
 248         } else if (old_orig)
 249                 delete_ref("ORIG_HEAD", old_orig, 0);
 250         set_reflog_message(&msg, "updating HEAD", rev);
 251         update_ref_status = update_ref(msg.buf, "HEAD", sha1, orig, 0, MSG_ON_ERR);
 252         strbuf_release(&msg);
 253         return update_ref_status;
 254 }
 255
 256 int cmd_reset(int argc, const char **argv, const char *prefix)
 257 {
 258         int reset_type = NONE, update_ref_status = 0, quiet = 0;
 259         int patch_mode = 0;
 260         const char *rev;
 261         unsigned char sha1[20];
 262         const char **pathspec = NULL;
 263         struct commit *commit;
 264         const struct option options[] = {
 265                 OPT__QUIET(&quiet, N_("be quiet, only report errors")),
 266                 OPT_SET_INT(0, "mixed", &reset_type,
 267                                                 N_("reset HEAD and index"), MIXED),
 268                 OPT_SET_INT(0, "soft", &reset_type, N_("reset only HEAD"), SOFT),
 269                 OPT_SET_INT(0, "hard", &reset_type,
 270                                 N_("reset HEAD, index and working tree"), HARD),
 271                 OPT_SET_INT(0, "merge", &reset_type,
 272                                 N_("reset HEAD, index and working tree"), MERGE),
 273                 OPT_SET_INT(0, "keep", &reset_type,
 274                                 N_("reset HEAD but keep local changes"), KEEP),
 275                 OPT_BOOLEAN('p', "patch", &patch_mode, N_("select hunks interactively")),
 276                 OPT_END()
 277         };
 278
 279         git_config(git_default_config, NULL);
 280
 281         argc = parse_options(argc, argv, prefix, options, git_reset_usage,
 282                                                 PARSE_OPT_KEEP_DASHDASH);
 283         pathspec = parse_args(argv, prefix, &rev);
 284
 285         if (get_sha1_committish(rev, sha1))
 286                 die(_("Failed to resolve '%s' as a valid ref."), rev);
 287
 288         /*
 289          * NOTE: As "git reset $treeish -- $path" should be usable on
 290          * any tree-ish, this is not strictly correct. We are not
 291          * moving the HEAD to any commit; we are merely resetting the
 292          * entries in the index to that of a treeish.
 293          */
 294         commit = lookup_commit_reference(sha1);
 295         if (!commit)
 296                 die(_("Could not parse object '%s'."), rev);
 297         hashcpy(sha1, commit->object.sha1);
 298
 299         if (patch_mode) {
 300                 if (reset_type != NONE)
 301                         die(_("--patch is incompatible with --{hard,mixed,soft}"));
 302                 return run_add_interactive(rev, "--patch=reset", pathspec);
 303         }
 304
 305         /* git reset tree [--] paths... can be used to
 306          * load chosen paths from the tree into the index without
 307          * affecting the working tree nor HEAD. */
 308         if (pathspec) {
 309                 if (reset_type == MIXED)
 310                         warning(_("--mixed with paths is deprecated; use 'git reset -- <paths>' instead."));
 311                 else if (reset_type != NONE)
 312                         die(_("Cannot do %s reset with paths."),
 313                                         _(reset_type_names[reset_type]));
 314         }
 315         if (reset_type == NONE)
 316                 reset_type = MIXED; /* by default */
 317
 318         if (reset_type != SOFT && reset_type != MIXED)
 319                 setup_work_tree();
 320
 321         if (reset_type == MIXED && is_bare_repository())
 322                 die(_("%s reset is not allowed in a bare repository"),
 323                     _(reset_type_names[reset_type]));
 324
 325         if (pathspec)
 326                 return read_from_tree(pathspec, sha1,
 327                                 quiet ? REFRESH_QUIET : REFRESH_IN_PORCELAIN);
 328
 329         /* Soft reset does not touch the index file nor the working tree
 330          * at all, but requires them in a good order.  Other resets reset
 331          * the index file to the tree object we are switching to. */
 332         if (reset_type == SOFT || reset_type == KEEP)
 333                 die_if_unmerged_cache(reset_type);
 334
 335         if (reset_type != SOFT) {
 336                 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
 337                 int newfd = hold_locked_index(lock, 1);
 338                 int err = reset_index(sha1, reset_type, quiet);
 339                 if (reset_type == KEEP && !err)
 340                         err = reset_index(sha1, MIXED, quiet);
 341                 if (err)
 342                         die(_("Could not reset index file to revision '%s'."), rev);
 343                 if (write_cache(newfd, active_cache, active_nr) ||
 344                     commit_locked_index(lock))
 345                         die(_("Could not write new index file."));
 346         }
 347
 348         /* Any resets update HEAD to the head being switched to,
 349          * saving the previous head in ORIG_HEAD before. */
 350         update_ref_status = update_refs(rev, sha1);
 351
 352         if (reset_type == HARD && !update_ref_status && !quiet)
 353                 print_new_head_line(commit);
 354         else if (reset_type == MIXED) /* Report what has not been updated. */
 355                 update_index_refresh(0, NULL,
 356                                 quiet ? REFRESH_QUIET : REFRESH_IN_PORCELAIN);
 357
 358         remove_branch_state();
 359
 360         return update_ref_status;
 361 }