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         "mixed", "soft", "hard", "merge", "keep", NULL
  34 };
  35
  36 static char *args_to_str(const char **argv)
  37 {
  38         char *buf = NULL;
  39         unsigned long len, space = 0, nr = 0;
  40
  41         for (; *argv; argv++) {
  42                 len = strlen(*argv);
  43                 ALLOC_GROW(buf, nr + 1 + len, space);
  44                 if (nr)
  45                         buf[nr++] = ' ';
  46                 memcpy(buf + nr, *argv, len);
  47                 nr += len;
  48         }
  49         ALLOC_GROW(buf, nr + 1, space);
  50         buf[nr] = '\0';
  51
  52         return buf;
  53 }
  54
  55 static inline int is_merge(void)
  56 {
  57         return !access(git_path("MERGE_HEAD"), F_OK);
  58 }
  59
  60 static int reset_index_file(const unsigned char *sha1, int reset_type, int quiet)
  61 {
  62         int nr = 1;
  63         int newfd;
  64         struct tree_desc desc[2];
  65         struct unpack_trees_options opts;
  66         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
  67
  68         memset(&opts, 0, sizeof(opts));
  69         opts.head_idx = 1;
  70         opts.src_index = &the_index;
  71         opts.dst_index = &the_index;
  72         opts.fn = oneway_merge;
  73         opts.merge = 1;
  74         if (!quiet)
  75                 opts.verbose_update = 1;
  76         switch (reset_type) {
  77         case KEEP:
  78         case MERGE:
  79                 opts.update = 1;
  80                 break;
  81         case HARD:
  82                 opts.update = 1;
  83                 /* fallthrough */
  84         default:
  85                 opts.reset = 1;
  86         }
  87
  88         newfd = hold_locked_index(lock, 1);
  89
  90         read_cache_unmerged();
  91
  92         if (reset_type == KEEP) {
  93                 unsigned char head_sha1[20];
  94                 if (get_sha1("HEAD", head_sha1))
  95                         return error("You do not have a valid HEAD.");
  96                 if (!fill_tree_descriptor(desc, head_sha1))
  97                         return error("Failed to find tree of HEAD.");
  98                 nr++;
  99                 opts.fn = twoway_merge;
 100         }
 101
 102         if (!fill_tree_descriptor(desc + nr - 1, sha1))
 103                 return error("Failed to find tree of %s.", sha1_to_hex(sha1));
 104         if (unpack_trees(nr, desc, &opts))
 105                 return -1;
 106         if (write_cache(newfd, active_cache, active_nr) ||
 107             commit_locked_index(lock))
 108                 return error("Could not write new index file.");
 109
 110         return 0;
 111 }
 112
 113 static void print_new_head_line(struct commit *commit)
 114 {
 115         const char *hex, *body;
 116
 117         hex = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
 118         printf("HEAD is now at %s", hex);
 119         body = strstr(commit->buffer, "\n\n");
 120         if (body) {
 121                 const char *eol;
 122                 size_t len;
 123                 body += 2;
 124                 eol = strchr(body, '\n');
 125                 len = eol ? eol - body : strlen(body);
 126                 printf(" %.*s\n", (int) len, body);
 127         }
 128         else
 129                 printf("\n");
 130 }
 131
 132 static int update_index_refresh(int fd, struct lock_file *index_lock, int flags)
 133 {
 134         int result;
 135
 136         if (!index_lock) {
 137                 index_lock = xcalloc(1, sizeof(struct lock_file));
 138                 fd = hold_locked_index(index_lock, 1);
 139         }
 140
 141         if (read_cache() < 0)
 142                 return error("Could not read index");
 143
 144         result = refresh_index(&the_index, (flags), NULL, NULL,
 145                                "Unstaged changes after reset:") ? 1 : 0;
 146         if (write_cache(fd, active_cache, active_nr) ||
 147                         commit_locked_index(index_lock))
 148                 return error ("Could not refresh index");
 149         return result;
 150 }
 151
 152 static void update_index_from_diff(struct diff_queue_struct *q,
 153                 struct diff_options *opt, void *data)
 154 {
 155         int i;
 156         int *discard_flag = data;
 157
 158         /* do_diff_cache() mangled the index */
 159         discard_cache();
 160         *discard_flag = 1;
 161         read_cache();
 162
 163         for (i = 0; i < q->nr; i++) {
 164                 struct diff_filespec *one = q->queue[i]->one;
 165                 if (one->mode) {
 166                         struct cache_entry *ce;
 167                         ce = make_cache_entry(one->mode, one->sha1, one->path,
 168                                 0, 0);
 169                         if (!ce)
 170                                 die("make_cache_entry failed for path '%s'",
 171                                     one->path);
 172                         add_cache_entry(ce, ADD_CACHE_OK_TO_ADD |
 173                                 ADD_CACHE_OK_TO_REPLACE);
 174                 } else
 175                         remove_file_from_cache(one->path);
 176         }
 177 }
 178
 179 static int interactive_reset(const char *revision, const char **argv,
 180                              const char *prefix)
 181 {
 182         const char **pathspec = NULL;
 183
 184         if (*argv)
 185                 pathspec = get_pathspec(prefix, argv);
 186
 187         return run_add_interactive(revision, "--patch=reset", pathspec);
 188 }
 189
 190 static int read_from_tree(const char *prefix, const char **argv,
 191                 unsigned char *tree_sha1, int refresh_flags)
 192 {
 193         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
 194         int index_fd, index_was_discarded = 0;
 195         struct diff_options opt;
 196
 197         memset(&opt, 0, sizeof(opt));
 198         diff_tree_setup_paths(get_pathspec(prefix, (const char **)argv), &opt);
 199         opt.output_format = DIFF_FORMAT_CALLBACK;
 200         opt.format_callback = update_index_from_diff;
 201         opt.format_callback_data = &index_was_discarded;
 202
 203         index_fd = hold_locked_index(lock, 1);
 204         index_was_discarded = 0;
 205         read_cache();
 206         if (do_diff_cache(tree_sha1, &opt))
 207                 return 1;
 208         diffcore_std(&opt);
 209         diff_flush(&opt);
 210         diff_tree_release_paths(&opt);
 211
 212         if (!index_was_discarded)
 213                 /* The index is still clobbered from do_diff_cache() */
 214                 discard_cache();
 215         return update_index_refresh(index_fd, lock, refresh_flags);
 216 }
 217
 218 static void prepend_reflog_action(const char *action, char *buf, size_t size)
 219 {
 220         const char *sep = ": ";
 221         const char *rla = getenv("GIT_REFLOG_ACTION");
 222         if (!rla)
 223                 rla = sep = "";
 224         if (snprintf(buf, size, "%s%s%s", rla, sep, action) >= size)
 225                 warning("Reflog action message too long: %.*s...", 50, buf);
 226 }
 227
 228 static void die_if_unmerged_cache(int reset_type)
 229 {
 230         if (is_merge() || read_cache() < 0 || unmerged_cache())
 231                 die("Cannot do a %s reset in the middle of a merge.",
 232                     reset_type_names[reset_type]);
 233
 234 }
 235
 236 int cmd_reset(int argc, const char **argv, const char *prefix)
 237 {
 238         int i = 0, reset_type = NONE, update_ref_status = 0, quiet = 0;
 239         int patch_mode = 0;
 240         const char *rev = "HEAD";
 241         unsigned char sha1[20], *orig = NULL, sha1_orig[20],
 242                                 *old_orig = NULL, sha1_old_orig[20];
 243         struct commit *commit;
 244         char *reflog_action, msg[1024];
 245         const struct option options[] = {
 246                 OPT__QUIET(&quiet, "be quiet, only report errors"),
 247                 OPT_SET_INT(0, "mixed", &reset_type,
 248                                                 "reset HEAD and index", MIXED),
 249                 OPT_SET_INT(0, "soft", &reset_type, "reset only HEAD", SOFT),
 250                 OPT_SET_INT(0, "hard", &reset_type,
 251                                 "reset HEAD, index and working tree", HARD),
 252                 OPT_SET_INT(0, "merge", &reset_type,
 253                                 "reset HEAD, index and working tree", MERGE),
 254                 OPT_SET_INT(0, "keep", &reset_type,
 255                                 "reset HEAD but keep local changes", KEEP),
 256                 OPT_BOOLEAN('p', "patch", &patch_mode, "select hunks interactively"),
 257                 OPT_END()
 258         };
 259
 260         git_config(git_default_config, NULL);
 261
 262         argc = parse_options(argc, argv, prefix, options, git_reset_usage,
 263                                                 PARSE_OPT_KEEP_DASHDASH);
 264         reflog_action = args_to_str(argv);
 265         setenv("GIT_REFLOG_ACTION", reflog_action, 0);
 266
 267         /*
 268          * Possible arguments are:
 269          *
 270          * git reset [-opts] <rev> <paths>...
 271          * git reset [-opts] <rev> -- <paths>...
 272          * git reset [-opts] -- <paths>...
 273          * git reset [-opts] <paths>...
 274          *
 275          * At this point, argv[i] points immediately after [-opts].
 276          */
 277
 278         if (i < argc) {
 279                 if (!strcmp(argv[i], "--")) {
 280                         i++; /* reset to HEAD, possibly with paths */
 281                 } else if (i + 1 < argc && !strcmp(argv[i+1], "--")) {
 282                         rev = argv[i];
 283                         i += 2;
 284                 }
 285                 /*
 286                  * Otherwise, argv[i] could be either <rev> or <paths> and
 287                  * has to be unambiguous.
 288                  */
 289                 else if (!get_sha1(argv[i], sha1)) {
 290                         /*
 291                          * Ok, argv[i] looks like a rev; it should not
 292                          * be a filename.
 293                          */
 294                         verify_non_filename(prefix, argv[i]);
 295                         rev = argv[i++];
 296                 } else {
 297                         /* Otherwise we treat this as a filename */
 298                         verify_filename(prefix, argv[i]);
 299                 }
 300         }
 301
 302         if (get_sha1(rev, sha1))
 303                 die("Failed to resolve '%s' as a valid ref.", rev);
 304
 305         commit = lookup_commit_reference(sha1);
 306         if (!commit)
 307                 die("Could not parse object '%s'.", rev);
 308         hashcpy(sha1, commit->object.sha1);
 309
 310         if (patch_mode) {
 311                 if (reset_type != NONE)
 312                         die("--patch is incompatible with --{hard,mixed,soft}");
 313                 return interactive_reset(rev, argv + i, prefix);
 314         }
 315
 316         /* git reset tree [--] paths... can be used to
 317          * load chosen paths from the tree into the index without
 318          * affecting the working tree nor HEAD. */
 319         if (i < argc) {
 320                 if (reset_type == MIXED)
 321                         warning("--mixed with paths is deprecated; use 'git reset -- <paths>' instead.");
 322                 else if (reset_type != NONE)
 323                         die("Cannot do %s reset with paths.",
 324                                         reset_type_names[reset_type]);
 325                 return read_from_tree(prefix, argv + i, sha1,
 326                                 quiet ? REFRESH_QUIET : REFRESH_IN_PORCELAIN);
 327         }
 328         if (reset_type == NONE)
 329                 reset_type = MIXED; /* by default */
 330
 331         if (reset_type != SOFT && reset_type != MIXED)
 332                 setup_work_tree();
 333
 334         if (reset_type == MIXED && is_bare_repository())
 335                 die("%s reset is not allowed in a bare repository",
 336                     reset_type_names[reset_type]);
 337
 338         /* Soft reset does not touch the index file nor the working tree
 339          * at all, but requires them in a good order.  Other resets reset
 340          * the index file to the tree object we are switching to. */
 341         if (reset_type == SOFT)
 342                 die_if_unmerged_cache(reset_type);
 343         else {
 344                 int err;
 345                 if (reset_type == KEEP)
 346                         die_if_unmerged_cache(reset_type);
 347                 err = reset_index_file(sha1, reset_type, quiet);
 348                 if (reset_type == KEEP)
 349                         err = err || reset_index_file(sha1, MIXED, quiet);
 350                 if (err)
 351                         die("Could not reset index file to revision '%s'.", rev);
 352         }
 353
 354         /* Any resets update HEAD to the head being switched to,
 355          * saving the previous head in ORIG_HEAD before. */
 356         if (!get_sha1("ORIG_HEAD", sha1_old_orig))
 357                 old_orig = sha1_old_orig;
 358         if (!get_sha1("HEAD", sha1_orig)) {
 359                 orig = sha1_orig;
 360                 prepend_reflog_action("updating ORIG_HEAD", msg, sizeof(msg));
 361                 update_ref(msg, "ORIG_HEAD", orig, old_orig, 0, MSG_ON_ERR);
 362         }
 363         else if (old_orig)
 364                 delete_ref("ORIG_HEAD", old_orig, 0);
 365         prepend_reflog_action("updating HEAD", msg, sizeof(msg));
 366         update_ref_status = update_ref(msg, "HEAD", sha1, orig, 0, MSG_ON_ERR);
 367
 368         switch (reset_type) {
 369         case HARD:
 370                 if (!update_ref_status && !quiet)
 371                         print_new_head_line(commit);
 372                 break;
 373         case SOFT: /* Nothing else to do. */
 374                 break;
 375         case MIXED: /* Report what has not been updated. */
 376                 update_index_refresh(0, NULL,
 377                                 quiet ? REFRESH_QUIET : REFRESH_IN_PORCELAIN);
 378                 break;
 379         }
 380
 381         remove_branch_state();
 382
 383         free(reflog_action);
 384
 385         return update_ref_status;
 386 }