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] <tree-ish> [--] <paths>..."),
  27         N_("git reset --patch [<tree-ish>] [--] [<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 void update_index_from_diff(struct diff_queue_struct *q,
 113                 struct diff_options *opt, void *data)
 114 {
 115         int i;
 116
 117         for (i = 0; i < q->nr; i++) {
 118                 struct diff_filespec *one = q->queue[i]->one;
 119                 if (one->mode && !is_null_sha1(one->sha1)) {
 120                         struct cache_entry *ce;
 121                         ce = make_cache_entry(one->mode, one->sha1, one->path,
 122                                 0, 0);
 123                         if (!ce)
 124                                 die(_("make_cache_entry failed for path '%s'"),
 125                                     one->path);
 126                         add_cache_entry(ce, ADD_CACHE_OK_TO_ADD |
 127                                 ADD_CACHE_OK_TO_REPLACE);
 128                 } else
 129                         remove_file_from_cache(one->path);
 130         }
 131 }
 132
 133 static int read_from_tree(const char **pathspec, unsigned char *tree_sha1)
 134 {
 135         struct diff_options opt;
 136
 137         memset(&opt, 0, sizeof(opt));
 138         diff_tree_setup_paths(pathspec, &opt);
 139         opt.output_format = DIFF_FORMAT_CALLBACK;
 140         opt.format_callback = update_index_from_diff;
 141
 142         read_cache();
 143         if (do_diff_cache(tree_sha1, &opt))
 144                 return 1;
 145         diffcore_std(&opt);
 146         diff_flush(&opt);
 147         diff_tree_release_paths(&opt);
 148
 149         return 0;
 150 }
 151
 152 static void set_reflog_message(struct strbuf *sb, const char *action,
 153                                const char *rev)
 154 {
 155         const char *rla = getenv("GIT_REFLOG_ACTION");
 156
 157         strbuf_reset(sb);
 158         if (rla)
 159                 strbuf_addf(sb, "%s: %s", rla, action);
 160         else if (rev)
 161                 strbuf_addf(sb, "reset: moving to %s", rev);
 162         else
 163                 strbuf_addf(sb, "reset: %s", action);
 164 }
 165
 166 static void die_if_unmerged_cache(int reset_type)
 167 {
 168         if (is_merge() || read_cache() < 0 || unmerged_cache())
 169                 die(_("Cannot do a %s reset in the middle of a merge."),
 170                     _(reset_type_names[reset_type]));
 171
 172 }
 173
 174 static const char **parse_args(const char **argv, const char *prefix, const char **rev_ret)
 175 {
 176         const char *rev = "HEAD";
 177         unsigned char unused[20];
 178         /*
 179          * Possible arguments are:
 180          *
 181          * git reset [-opts] [<rev>]
 182          * git reset [-opts] <tree> [<paths>...]
 183          * git reset [-opts] <tree> -- [<paths>...]
 184          * git reset [-opts] -- [<paths>...]
 185          * git reset [-opts] <paths>...
 186          *
 187          * At this point, argv points immediately after [-opts].
 188          */
 189
 190         if (argv[0]) {
 191                 if (!strcmp(argv[0], "--")) {
 192                         argv++; /* reset to HEAD, possibly with paths */
 193                 } else if (argv[1] && !strcmp(argv[1], "--")) {
 194                         rev = argv[0];
 195                         argv += 2;
 196                 }
 197                 /*
 198                  * Otherwise, argv[0] could be either <rev> or <paths> and
 199                  * has to be unambiguous. If there is a single argument, it
 200                  * can not be a tree
 201                  */
 202                 else if ((!argv[1] && !get_sha1_committish(argv[0], unused)) ||
 203                          (argv[1] && !get_sha1_treeish(argv[0], unused))) {
 204                         /*
 205                          * Ok, argv[0] looks like a commit/tree; it should not
 206                          * be a filename.
 207                          */
 208                         verify_non_filename(prefix, argv[0]);
 209                         rev = *argv++;
 210                 } else {
 211                         /* Otherwise we treat this as a filename */
 212                         verify_filename(prefix, argv[0], 1);
 213                 }
 214         }
 215         *rev_ret = rev;
 216         return argv[0] ? get_pathspec(prefix, argv) : NULL;
 217 }
 218
 219 static int update_refs(const char *rev, const unsigned char *sha1)
 220 {
 221         int update_ref_status;
 222         struct strbuf msg = STRBUF_INIT;
 223         unsigned char *orig = NULL, sha1_orig[20],
 224                 *old_orig = NULL, sha1_old_orig[20];
 225
 226         if (!get_sha1("ORIG_HEAD", sha1_old_orig))
 227                 old_orig = sha1_old_orig;
 228         if (!get_sha1("HEAD", sha1_orig)) {
 229                 orig = sha1_orig;
 230                 set_reflog_message(&msg, "updating ORIG_HEAD", NULL);
 231                 update_ref(msg.buf, "ORIG_HEAD", orig, old_orig, 0, MSG_ON_ERR);
 232         } else if (old_orig)
 233                 delete_ref("ORIG_HEAD", old_orig, 0);
 234         set_reflog_message(&msg, "updating HEAD", rev);
 235         update_ref_status = update_ref(msg.buf, "HEAD", sha1, orig, 0, MSG_ON_ERR);
 236         strbuf_release(&msg);
 237         return update_ref_status;
 238 }
 239
 240 int cmd_reset(int argc, const char **argv, const char *prefix)
 241 {
 242         int reset_type = NONE, update_ref_status = 0, quiet = 0;
 243         int patch_mode = 0, unborn;
 244         const char *rev;
 245         unsigned char sha1[20];
 246         const char **pathspec = NULL;
 247         const struct option options[] = {
 248                 OPT__QUIET(&quiet, N_("be quiet, only report errors")),
 249                 OPT_SET_INT(0, "mixed", &reset_type,
 250                                                 N_("reset HEAD and index"), MIXED),
 251                 OPT_SET_INT(0, "soft", &reset_type, N_("reset only HEAD"), SOFT),
 252                 OPT_SET_INT(0, "hard", &reset_type,
 253                                 N_("reset HEAD, index and working tree"), HARD),
 254                 OPT_SET_INT(0, "merge", &reset_type,
 255                                 N_("reset HEAD, index and working tree"), MERGE),
 256                 OPT_SET_INT(0, "keep", &reset_type,
 257                                 N_("reset HEAD but keep local changes"), KEEP),
 258                 OPT_BOOLEAN('p', "patch", &patch_mode, N_("select hunks interactively")),
 259                 OPT_END()
 260         };
 261
 262         git_config(git_default_config, NULL);
 263
 264         argc = parse_options(argc, argv, prefix, options, git_reset_usage,
 265                                                 PARSE_OPT_KEEP_DASHDASH);
 266         pathspec = parse_args(argv, prefix, &rev);
 267
 268         unborn = !strcmp(rev, "HEAD") && get_sha1("HEAD", sha1);
 269         if (unborn) {
 270                 /* reset on unborn branch: treat as reset to empty tree */
 271                 hashcpy(sha1, EMPTY_TREE_SHA1_BIN);
 272         } else if (!pathspec) {
 273                 struct commit *commit;
 274                 if (get_sha1_committish(rev, sha1))
 275                         die(_("Failed to resolve '%s' as a valid revision."), rev);
 276                 commit = lookup_commit_reference(sha1);
 277                 if (!commit)
 278                         die(_("Could not parse object '%s'."), rev);
 279                 hashcpy(sha1, commit->object.sha1);
 280         } else {
 281                 struct tree *tree;
 282                 if (get_sha1_treeish(rev, sha1))
 283                         die(_("Failed to resolve '%s' as a valid tree."), rev);
 284                 tree = parse_tree_indirect(sha1);
 285                 if (!tree)
 286                         die(_("Could not parse object '%s'."), rev);
 287                 hashcpy(sha1, tree->object.sha1);
 288         }
 289
 290         if (patch_mode) {
 291                 if (reset_type != NONE)
 292                         die(_("--patch is incompatible with --{hard,mixed,soft}"));
 293                 return run_add_interactive(sha1_to_hex(sha1), "--patch=reset", pathspec);
 294         }
 295
 296         /* git reset tree [--] paths... can be used to
 297          * load chosen paths from the tree into the index without
 298          * affecting the working tree nor HEAD. */
 299         if (pathspec) {
 300                 if (reset_type == MIXED)
 301                         warning(_("--mixed with paths is deprecated; use 'git reset -- <paths>' instead."));
 302                 else if (reset_type != NONE)
 303                         die(_("Cannot do %s reset with paths."),
 304                                         _(reset_type_names[reset_type]));
 305         }
 306         if (reset_type == NONE)
 307                 reset_type = MIXED; /* by default */
 308
 309         if (reset_type != SOFT && reset_type != MIXED)
 310                 setup_work_tree();
 311
 312         if (reset_type == MIXED && is_bare_repository())
 313                 die(_("%s reset is not allowed in a bare repository"),
 314                     _(reset_type_names[reset_type]));
 315
 316         /* Soft reset does not touch the index file nor the working tree
 317          * at all, but requires them in a good order.  Other resets reset
 318          * the index file to the tree object we are switching to. */
 319         if (reset_type == SOFT || reset_type == KEEP)
 320                 die_if_unmerged_cache(reset_type);
 321
 322         if (reset_type != SOFT) {
 323                 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
 324                 int newfd = hold_locked_index(lock, 1);
 325                 if (reset_type == MIXED) {
 326                         if (read_from_tree(pathspec, sha1))
 327                                 return 1;
 328                 } else {
 329                         int err = reset_index(sha1, reset_type, quiet);
 330                         if (reset_type == KEEP && !err)
 331                                 err = reset_index(sha1, MIXED, quiet);
 332                         if (err)
 333                                 die(_("Could not reset index file to revision '%s'."), rev);
 334                 }
 335
 336                 if (reset_type == MIXED) { /* Report what has not been updated. */
 337                         int flags = quiet ? REFRESH_QUIET : REFRESH_IN_PORCELAIN;
 338                         refresh_index(&the_index, flags, NULL, NULL,
 339                                       _("Unstaged changes after reset:"));
 340                 }
 341
 342                 if (write_cache(newfd, active_cache, active_nr) ||
 343                     commit_locked_index(lock))
 344                         die(_("Could not write new index file."));
 345         }
 346
 347         if (!pathspec && !unborn) {
 348                 /* Any resets without paths update HEAD to the head being
 349                  * switched to, 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(lookup_commit_reference(sha1));
 354         }
 355         if (!pathspec)
 356                 remove_branch_state();
 357
 358         return update_ref_status;
 359 }