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 "cache.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 [--mixed] <commit> [--] <paths>...",
  27         NULL
  28 };
  29
  30 enum reset_type { MIXED, SOFT, HARD, MERGE, KEEP, NONE };
  31 static const char *reset_type_names[] = {
  32         "mixed", "soft", "hard", "merge", "keep", NULL
  33 };
  34
  35 static char *args_to_str(const char **argv)
  36 {
  37         char *buf = NULL;
  38         unsigned long len, space = 0, nr = 0;
  39
  40         for (; *argv; argv++) {
  41                 len = strlen(*argv);
  42                 ALLOC_GROW(buf, nr + 1 + len, space);
  43                 if (nr)
  44                         buf[nr++] = ' ';
  45                 memcpy(buf + nr, *argv, len);
  46                 nr += len;
  47         }
  48         ALLOC_GROW(buf, nr + 1, space);
  49         buf[nr] = '\0';
  50
  51         return buf;
  52 }
  53
  54 static inline int is_merge(void)
  55 {
  56         return !access(git_path("MERGE_HEAD"), F_OK);
  57 }
  58
  59 static int reset_index_file(const unsigned char *sha1, int reset_type, int quiet)
  60 {
  61         int nr = 1;
  62         int newfd;
  63         struct tree_desc desc[2];
  64         struct unpack_trees_options opts;
  65         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
  66
  67         memset(&opts, 0, sizeof(opts));
  68         opts.head_idx = 1;
  69         opts.src_index = &the_index;
  70         opts.dst_index = &the_index;
  71         opts.fn = oneway_merge;
  72         opts.merge = 1;
  73         if (!quiet)
  74                 opts.verbose_update = 1;
  75         switch (reset_type) {
  76         case KEEP:
  77         case MERGE:
  78                 opts.update = 1;
  79                 break;
  80         case HARD:
  81                 opts.update = 1;
  82                 /* fallthrough */
  83         default:
  84                 opts.reset = 1;
  85         }
  86
  87         newfd = hold_locked_index(lock, 1);
  88
  89         read_cache_unmerged();
  90
  91         if (reset_type == KEEP) {
  92                 unsigned char head_sha1[20];
  93                 if (get_sha1("HEAD", head_sha1))
  94                         return error("You do not have a valid HEAD.");
  95                 if (!fill_tree_descriptor(desc, head_sha1))
  96                         return error("Failed to find tree of HEAD.");
  97                 nr++;
  98                 opts.fn = twoway_merge;
  99         }
 100
 101         if (!fill_tree_descriptor(desc + nr - 1, sha1))
 102                 return error("Failed to find tree of %s.", sha1_to_hex(sha1));
 103         if (unpack_trees(nr, desc, &opts))
 104                 return -1;
 105         if (write_cache(newfd, active_cache, active_nr) ||
 106             commit_locked_index(lock))
 107                 return error("Could not write new index file.");
 108
 109         return 0;
 110 }
 111
 112 static void print_new_head_line(struct commit *commit)
 113 {
 114         const char *hex, *body;
 115
 116         hex = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
 117         printf("HEAD is now at %s", hex);
 118         body = strstr(commit->buffer, "\n\n");
 119         if (body) {
 120                 const char *eol;
 121                 size_t len;
 122                 body += 2;
 123                 eol = strchr(body, '\n');
 124                 len = eol ? eol - body : strlen(body);
 125                 printf(" %.*s\n", (int) len, body);
 126         }
 127         else
 128                 printf("\n");
 129 }
 130
 131 static int update_index_refresh(int fd, struct lock_file *index_lock, int flags)
 132 {
 133         int result;
 134
 135         if (!index_lock) {
 136                 index_lock = xcalloc(1, sizeof(struct lock_file));
 137                 fd = hold_locked_index(index_lock, 1);
 138         }
 139
 140         if (read_cache() < 0)
 141                 return error("Could not read index");
 142
 143         result = refresh_index(&the_index, (flags), NULL, NULL,
 144                                "Unstaged changes after reset:") ? 1 : 0;
 145         if (write_cache(fd, active_cache, active_nr) ||
 146                         commit_locked_index(index_lock))
 147                 return error ("Could not refresh index");
 148         return result;
 149 }
 150
 151 static void update_index_from_diff(struct diff_queue_struct *q,
 152                 struct diff_options *opt, void *data)
 153 {
 154         int i;
 155         int *discard_flag = data;
 156
 157         /* do_diff_cache() mangled the index */
 158         discard_cache();
 159         *discard_flag = 1;
 160         read_cache();
 161
 162         for (i = 0; i < q->nr; i++) {
 163                 struct diff_filespec *one = q->queue[i]->one;
 164                 if (one->mode) {
 165                         struct cache_entry *ce;
 166                         ce = make_cache_entry(one->mode, one->sha1, one->path,
 167                                 0, 0);
 168                         if (!ce)
 169                                 die("make_cache_entry failed for path '%s'",
 170                                     one->path);
 171                         add_cache_entry(ce, ADD_CACHE_OK_TO_ADD |
 172                                 ADD_CACHE_OK_TO_REPLACE);
 173                 } else
 174                         remove_file_from_cache(one->path);
 175         }
 176 }
 177
 178 static int interactive_reset(const char *revision, const char **argv,
 179                              const char *prefix)
 180 {
 181         const char **pathspec = NULL;
 182
 183         if (*argv)
 184                 pathspec = get_pathspec(prefix, argv);
 185
 186         return run_add_interactive(revision, "--patch=reset", pathspec);
 187 }
 188
 189 static int read_from_tree(const char *prefix, const char **argv,
 190                 unsigned char *tree_sha1, int refresh_flags)
 191 {
 192         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
 193         int index_fd, index_was_discarded = 0;
 194         struct diff_options opt;
 195
 196         memset(&opt, 0, sizeof(opt));
 197         diff_tree_setup_paths(get_pathspec(prefix, (const char **)argv), &opt);
 198         opt.output_format = DIFF_FORMAT_CALLBACK;
 199         opt.format_callback = update_index_from_diff;
 200         opt.format_callback_data = &index_was_discarded;
 201
 202         index_fd = hold_locked_index(lock, 1);
 203         index_was_discarded = 0;
 204         read_cache();
 205         if (do_diff_cache(tree_sha1, &opt))
 206                 return 1;
 207         diffcore_std(&opt);
 208         diff_flush(&opt);
 209         diff_tree_release_paths(&opt);
 210
 211         if (!index_was_discarded)
 212                 /* The index is still clobbered from do_diff_cache() */
 213                 discard_cache();
 214         return update_index_refresh(index_fd, lock, refresh_flags);
 215 }
 216
 217 static void prepend_reflog_action(const char *action, char *buf, size_t size)
 218 {
 219         const char *sep = ": ";
 220         const char *rla = getenv("GIT_REFLOG_ACTION");
 221         if (!rla)
 222                 rla = sep = "";
 223         if (snprintf(buf, size, "%s%s%s", rla, sep, action) >= size)
 224                 warning("Reflog action message too long: %.*s...", 50, buf);
 225 }
 226
 227 static void die_if_unmerged_cache(int reset_type)
 228 {
 229         if (is_merge() || read_cache() < 0 || unmerged_cache())
 230                 die("Cannot do a %s reset in the middle of a merge.",
 231                     reset_type_names[reset_type]);
 232
 233 }
 234
 235 int cmd_reset(int argc, const char **argv, const char *prefix)
 236 {
 237         int i = 0, reset_type = NONE, update_ref_status = 0, quiet = 0;
 238         int patch_mode = 0;
 239         const char *rev = "HEAD";
 240         unsigned char sha1[20], *orig = NULL, sha1_orig[20],
 241                                 *old_orig = NULL, sha1_old_orig[20];
 242         struct commit *commit;
 243         char *reflog_action, msg[1024];
 244         const struct option options[] = {
 245                 OPT__QUIET(&quiet),
 246                 OPT_SET_INT(0, "mixed", &reset_type,
 247                                                 "reset HEAD and index", MIXED),
 248                 OPT_SET_INT(0, "soft", &reset_type, "reset only HEAD", SOFT),
 249                 OPT_SET_INT(0, "hard", &reset_type,
 250                                 "reset HEAD, index and working tree", HARD),
 251                 OPT_SET_INT(0, "merge", &reset_type,
 252                                 "reset HEAD, index and working tree", MERGE),
 253                 OPT_SET_INT(0, "keep", &reset_type,
 254                                 "reset HEAD but keep local changes", KEEP),
 255                 OPT_BOOLEAN('p', "patch", &patch_mode, "select hunks interactively"),
 256                 OPT_END()
 257         };
 258
 259         git_config(git_default_config, NULL);
 260
 261         argc = parse_options(argc, argv, prefix, options, git_reset_usage,
 262                                                 PARSE_OPT_KEEP_DASHDASH);
 263         reflog_action = args_to_str(argv);
 264         setenv("GIT_REFLOG_ACTION", reflog_action, 0);
 265
 266         /*
 267          * Possible arguments are:
 268          *
 269          * git reset [-opts] <rev> <paths>...
 270          * git reset [-opts] <rev> -- <paths>...
 271          * git reset [-opts] -- <paths>...
 272          * git reset [-opts] <paths>...
 273          *
 274          * At this point, argv[i] points immediately after [-opts].
 275          */
 276
 277         if (i < argc) {
 278                 if (!strcmp(argv[i], "--")) {
 279                         i++; /* reset to HEAD, possibly with paths */
 280                 } else if (i + 1 < argc && !strcmp(argv[i+1], "--")) {
 281                         rev = argv[i];
 282                         i += 2;
 283                 }
 284                 /*
 285                  * Otherwise, argv[i] could be either <rev> or <paths> and
 286                  * has to be unambiguous.
 287                  */
 288                 else if (!get_sha1(argv[i], sha1)) {
 289                         /*
 290                          * Ok, argv[i] looks like a rev; it should not
 291                          * be a filename.
 292                          */
 293                         verify_non_filename(prefix, argv[i]);
 294                         rev = argv[i++];
 295                 } else {
 296                         /* Otherwise we treat this as a filename */
 297                         verify_filename(prefix, argv[i]);
 298                 }
 299         }
 300
 301         if (get_sha1(rev, sha1))
 302                 die("Failed to resolve '%s' as a valid ref.", rev);
 303
 304         commit = lookup_commit_reference(sha1);
 305         if (!commit)
 306                 die("Could not parse object '%s'.", rev);
 307         hashcpy(sha1, commit->object.sha1);
 308
 309         if (patch_mode) {
 310                 if (reset_type != NONE)
 311                         die("--patch is incompatible with --{hard,mixed,soft}");
 312                 return interactive_reset(rev, argv + i, prefix);
 313         }
 314
 315         /* git reset tree [--] paths... can be used to
 316          * load chosen paths from the tree into the index without
 317          * affecting the working tree nor HEAD. */
 318         if (i < argc) {
 319                 if (reset_type == MIXED)
 320                         warning("--mixed option is deprecated with paths.");
 321                 else if (reset_type != NONE)
 322                         die("Cannot do %s reset with paths.",
 323                                         reset_type_names[reset_type]);
 324                 return read_from_tree(prefix, argv + i, sha1,
 325                                 quiet ? REFRESH_QUIET : REFRESH_IN_PORCELAIN);
 326         }
 327         if (reset_type == NONE)
 328                 reset_type = MIXED; /* by default */
 329
 330         if (reset_type != SOFT && reset_type != MIXED)
 331                 setup_work_tree();
 332
 333         if (reset_type == MIXED && is_bare_repository())
 334                 die("%s reset is not allowed in a bare repository",
 335                     reset_type_names[reset_type]);
 336
 337         /* Soft reset does not touch the index file nor the working tree
 338          * at all, but requires them in a good order.  Other resets reset
 339          * the index file to the tree object we are switching to. */
 340         if (reset_type == SOFT)
 341                 die_if_unmerged_cache(reset_type);
 342         else {
 343                 int err;
 344                 if (reset_type == KEEP)
 345                         die_if_unmerged_cache(reset_type);
 346                 err = reset_index_file(sha1, reset_type, quiet);
 347                 if (reset_type == KEEP)
 348                         err = err || reset_index_file(sha1, MIXED, quiet);
 349                 if (err)
 350                         die("Could not reset index file to revision '%s'.", rev);
 351         }
 352
 353         /* Any resets update HEAD to the head being switched to,
 354          * saving the previous head in ORIG_HEAD before. */
 355         if (!get_sha1("ORIG_HEAD", sha1_old_orig))
 356                 old_orig = sha1_old_orig;
 357         if (!get_sha1("HEAD", sha1_orig)) {
 358                 orig = sha1_orig;
 359                 prepend_reflog_action("updating ORIG_HEAD", msg, sizeof(msg));
 360                 update_ref(msg, "ORIG_HEAD", orig, old_orig, 0, MSG_ON_ERR);
 361         }
 362         else if (old_orig)
 363                 delete_ref("ORIG_HEAD", old_orig, 0);
 364         prepend_reflog_action("updating HEAD", msg, sizeof(msg));
 365         update_ref_status = update_ref(msg, "HEAD", sha1, orig, 0, MSG_ON_ERR);
 366
 367         switch (reset_type) {
 368         case HARD:
 369                 if (!update_ref_status && !quiet)
 370                         print_new_head_line(commit);
 371                 break;
 372         case SOFT: /* Nothing else to do. */
 373                 break;
 374         case MIXED: /* Report what has not been updated. */
 375                 update_index_refresh(0, NULL,
 376                                 quiet ? REFRESH_QUIET : REFRESH_IN_PORCELAIN);
 377                 break;
 378         }
 379
 380         remove_branch_state();
 381
 382         free(reflog_action);
 383
 384         return update_ref_status;
 385 }