builtin-checkout.c

   1 #include "cache.h"
   2 #include "builtin.h"
   3 #include "parse-options.h"
   4 #include "refs.h"
   5 #include "commit.h"
   6 #include "tree.h"
   7 #include "tree-walk.h"
   8 #include "unpack-trees.h"
   9 #include "dir.h"
  10 #include "run-command.h"
  11 #include "merge-recursive.h"
  12 #include "branch.h"
  13 #include "diff.h"
  14 #include "revision.h"
  15
  16 static const char * const checkout_usage[] = {
  17         "git checkout [options] <branch>",
  18         "git checkout [options] [<branch>] -- <file>...",
  19         NULL,
  20 };
  21
  22 static int post_checkout_hook(struct commit *old, struct commit *new,
  23                               int changed)
  24 {
  25         struct child_process proc;
  26         const char *name = git_path("hooks/post-checkout");
  27         const char *argv[5];
  28
  29         if (access(name, X_OK) < 0)
  30                 return 0;
  31
  32         memset(&proc, 0, sizeof(proc));
  33         argv[0] = name;
  34         argv[1] = xstrdup(sha1_to_hex(old->object.sha1));
  35         argv[2] = xstrdup(sha1_to_hex(new->object.sha1));
  36         argv[3] = changed ? "1" : "0";
  37         argv[4] = NULL;
  38         proc.argv = argv;
  39         proc.no_stdin = 1;
  40         proc.stdout_to_stderr = 1;
  41         return run_command(&proc);
  42 }
  43
  44 static int update_some(const unsigned char *sha1, const char *base, int baselen,
  45                        const char *pathname, unsigned mode, int stage)
  46 {
  47         int len;
  48         struct cache_entry *ce;
  49
  50         if (S_ISGITLINK(mode))
  51                 return 0;
  52
  53         if (S_ISDIR(mode))
  54                 return READ_TREE_RECURSIVE;
  55
  56         len = baselen + strlen(pathname);
  57         ce = xcalloc(1, cache_entry_size(len));
  58         hashcpy(ce->sha1, sha1);
  59         memcpy(ce->name, base, baselen);
  60         memcpy(ce->name + baselen, pathname, len - baselen);
  61         ce->ce_flags = create_ce_flags(len, 0);
  62         ce->ce_mode = create_ce_mode(mode);
  63         add_cache_entry(ce, ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
  64         return 0;
  65 }
  66
  67 static int read_tree_some(struct tree *tree, const char **pathspec)
  68 {
  69         int newfd;
  70         struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
  71         newfd = hold_locked_index(lock_file, 1);
  72         read_cache();
  73
  74         read_tree_recursive(tree, "", 0, 0, pathspec, update_some);
  75
  76         if (write_cache(newfd, active_cache, active_nr) ||
  77             commit_locked_index(lock_file))
  78                 die("unable to write new index file");
  79
  80         /* update the index with the given tree's info
  81          * for all args, expanding wildcards, and exit
  82          * with any non-zero return code.
  83          */
  84         return 0;
  85 }
  86
  87 static int checkout_paths(const char **pathspec)
  88 {
  89         int pos;
  90         struct checkout state;
  91         static char *ps_matched;
  92         unsigned char rev[20];
  93         int flag;
  94         struct commit *head;
  95
  96         for (pos = 0; pathspec[pos]; pos++)
  97                 ;
  98         ps_matched = xcalloc(1, pos);
  99
 100         for (pos = 0; pos < active_nr; pos++) {
 101                 struct cache_entry *ce = active_cache[pos];
 102                 pathspec_match(pathspec, ps_matched, ce->name, 0);
 103         }
 104
 105         if (report_path_error(ps_matched, pathspec, 0))
 106                 return 1;
 107
 108         memset(&state, 0, sizeof(state));
 109         state.force = 1;
 110         state.refresh_cache = 1;
 111         for (pos = 0; pos < active_nr; pos++) {
 112                 struct cache_entry *ce = active_cache[pos];
 113                 if (pathspec_match(pathspec, NULL, ce->name, 0)) {
 114                         checkout_entry(ce, &state, NULL);
 115                 }
 116         }
 117
 118         resolve_ref("HEAD", rev, 0, &flag);
 119         head = lookup_commit_reference_gently(rev, 1);
 120
 121         return post_checkout_hook(head, head, 0);
 122 }
 123
 124 static void show_local_changes(struct object *head)
 125 {
 126         struct rev_info rev;
 127         /* I think we want full paths, even if we're in a subdirectory. */
 128         init_revisions(&rev, NULL);
 129         rev.abbrev = 0;
 130         rev.diffopt.output_format |= DIFF_FORMAT_NAME_STATUS;
 131         add_pending_object(&rev, head, NULL);
 132         run_diff_index(&rev, 0);
 133 }
 134
 135 static void describe_detached_head(char *msg, struct commit *commit)
 136 {
 137         struct strbuf sb;
 138         strbuf_init(&sb, 0);
 139         parse_commit(commit);
 140         pretty_print_commit(CMIT_FMT_ONELINE, commit, &sb, 0, "", "", 0, 0);
 141         fprintf(stderr, "%s %s... %s\n", msg,
 142                 find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV), sb.buf);
 143         strbuf_release(&sb);
 144 }
 145
 146 static int reset_to_new(struct tree *tree, int quiet)
 147 {
 148         struct unpack_trees_options opts;
 149         struct tree_desc tree_desc;
 150         memset(&opts, 0, sizeof(opts));
 151         opts.head_idx = -1;
 152         opts.update = 1;
 153         opts.reset = 1;
 154         opts.merge = 1;
 155         opts.fn = oneway_merge;
 156         opts.verbose_update = !quiet;
 157         parse_tree(tree);
 158         init_tree_desc(&tree_desc, tree->buffer, tree->size);
 159         if (unpack_trees(1, &tree_desc, &opts))
 160                 return 128;
 161         return 0;
 162 }
 163
 164 static void reset_clean_to_new(struct tree *tree, int quiet)
 165 {
 166         struct unpack_trees_options opts;
 167         struct tree_desc tree_desc;
 168         memset(&opts, 0, sizeof(opts));
 169         opts.head_idx = -1;
 170         opts.skip_unmerged = 1;
 171         opts.reset = 1;
 172         opts.merge = 1;
 173         opts.fn = oneway_merge;
 174         opts.verbose_update = !quiet;
 175         parse_tree(tree);
 176         init_tree_desc(&tree_desc, tree->buffer, tree->size);
 177         if (unpack_trees(1, &tree_desc, &opts))
 178                 exit(128);
 179 }
 180
 181 struct checkout_opts {
 182         int quiet;
 183         int merge;
 184         int force;
 185
 186         char *new_branch;
 187         int new_branch_log;
 188         int track;
 189 };
 190
 191 struct branch_info {
 192         const char *name; /* The short name used */
 193         const char *path; /* The full name of a real branch */
 194         struct commit *commit; /* The named commit */
 195 };
 196
 197 static void setup_branch_path(struct branch_info *branch)
 198 {
 199         struct strbuf buf;
 200         strbuf_init(&buf, 0);
 201         strbuf_addstr(&buf, "refs/heads/");
 202         strbuf_addstr(&buf, branch->name);
 203         branch->path = strbuf_detach(&buf, NULL);
 204 }
 205
 206 static int merge_working_tree(struct checkout_opts *opts,
 207                               struct branch_info *old, struct branch_info *new,
 208                               const char *prefix)
 209 {
 210         int ret;
 211         struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
 212         int newfd = hold_locked_index(lock_file, 1);
 213         read_cache();
 214
 215         if (opts->force) {
 216                 ret = reset_to_new(new->commit->tree, opts->quiet);
 217                 if (ret)
 218                         return ret;
 219         } else {
 220                 struct tree_desc trees[2];
 221                 struct tree *tree;
 222                 struct unpack_trees_options topts;
 223                 memset(&topts, 0, sizeof(topts));
 224                 topts.head_idx = -1;
 225
 226                 refresh_cache(REFRESH_QUIET);
 227
 228                 if (unmerged_cache()) {
 229                         ret = opts->merge ? -1 :
 230                                 error("you need to resolve your current index first");
 231                 } else {
 232                         topts.update = 1;
 233                         topts.merge = 1;
 234                         topts.gently = opts->merge;
 235                         topts.fn = twoway_merge;
 236                         topts.dir = xcalloc(1, sizeof(*topts.dir));
 237                         topts.dir->show_ignored = 1;
 238                         topts.dir->exclude_per_dir = ".gitignore";
 239                         topts.prefix = prefix;
 240                         tree = parse_tree_indirect(old->commit->object.sha1);
 241                         init_tree_desc(&trees[0], tree->buffer, tree->size);
 242                         tree = parse_tree_indirect(new->commit->object.sha1);
 243                         init_tree_desc(&trees[1], tree->buffer, tree->size);
 244                         ret = unpack_trees(2, trees, &topts);
 245                 }
 246                 if (ret) {
 247                         /*
 248                          * Unpack couldn't do a trivial merge; either
 249                          * give up or do a real merge, depending on
 250                          * whether the merge flag was used.
 251                          */
 252                         struct tree *result;
 253                         struct tree *work;
 254                         if (!opts->merge)
 255                                 return 1;
 256                         parse_commit(old->commit);
 257
 258                         /* Do more real merge */
 259
 260                         /*
 261                          * We update the index fully, then write the
 262                          * tree from the index, then merge the new
 263                          * branch with the current tree, with the old
 264                          * branch as the base. Then we reset the index
 265                          * (but not the working tree) to the new
 266                          * branch, leaving the working tree as the
 267                          * merged version, but skipping unmerged
 268                          * entries in the index.
 269                          */
 270
 271                         add_files_to_cache(0, NULL, NULL);
 272                         work = write_tree_from_memory();
 273
 274                         ret = reset_to_new(new->commit->tree, opts->quiet);
 275                         if (ret)
 276                                 return ret;
 277                         merge_trees(new->commit->tree, work, old->commit->tree,
 278                                     new->name, "local", &result);
 279                         reset_clean_to_new(new->commit->tree, opts->quiet);
 280                 }
 281         }
 282
 283         if (write_cache(newfd, active_cache, active_nr) ||
 284             commit_locked_index(lock_file))
 285                 die("unable to write new index file");
 286
 287         if (!opts->force)
 288                 show_local_changes(&new->commit->object);
 289
 290         return 0;
 291 }
 292
 293 static void update_refs_for_switch(struct checkout_opts *opts,
 294                                    struct branch_info *old,
 295                                    struct branch_info *new)
 296 {
 297         struct strbuf msg;
 298         const char *old_desc;
 299         if (opts->new_branch) {
 300                 create_branch(old->name, opts->new_branch, new->name, 0,
 301                               opts->new_branch_log, opts->track);
 302                 new->name = opts->new_branch;
 303                 setup_branch_path(new);
 304         }
 305
 306         strbuf_init(&msg, 0);
 307         old_desc = old->name;
 308         if (!old_desc)
 309                 old_desc = sha1_to_hex(old->commit->object.sha1);
 310         strbuf_addf(&msg, "checkout: moving from %s to %s",
 311                     old_desc, new->name);
 312
 313         if (new->path) {
 314                 create_symref("HEAD", new->path, msg.buf);
 315                 if (!opts->quiet) {
 316                         if (old->path && !strcmp(new->path, old->path))
 317                                 fprintf(stderr, "Already on \"%s\"\n",
 318                                         new->name);
 319                         else
 320                                 fprintf(stderr, "Switched to%s branch \"%s\"\n",
 321                                         opts->new_branch ? " a new" : "",
 322                                         new->name);
 323                 }
 324         } else if (strcmp(new->name, "HEAD")) {
 325                 update_ref(msg.buf, "HEAD", new->commit->object.sha1, NULL,
 326                            REF_NODEREF, DIE_ON_ERR);
 327                 if (!opts->quiet) {
 328                         if (old->path)
 329                                 fprintf(stderr, "Note: moving to \"%s\" which isn't a local branch\nIf you want to create a new branch from this checkout, you may do so\n(now or later) by using -b with the checkout command again. Example:\n  git checkout -b <new_branch_name>\n", new->name);
 330                         describe_detached_head("HEAD is now at", new->commit);
 331                 }
 332         }
 333         remove_branch_state();
 334         strbuf_release(&msg);
 335 }
 336
 337 static int switch_branches(struct checkout_opts *opts,
 338                            struct branch_info *new, const char *prefix)
 339 {
 340         int ret = 0;
 341         struct branch_info old;
 342         unsigned char rev[20];
 343         int flag;
 344         memset(&old, 0, sizeof(old));
 345         old.path = resolve_ref("HEAD", rev, 0, &flag);
 346         old.commit = lookup_commit_reference_gently(rev, 1);
 347         if (!(flag & REF_ISSYMREF))
 348                 old.path = NULL;
 349
 350         if (old.path && !prefixcmp(old.path, "refs/heads/"))
 351                 old.name = old.path + strlen("refs/heads/");
 352
 353         if (!new->name) {
 354                 new->name = "HEAD";
 355                 new->commit = old.commit;
 356                 if (!new->commit)
 357                         die("You are on a branch yet to be born");
 358                 parse_commit(new->commit);
 359         }
 360
 361         /*
 362          * If the new thing isn't a branch and isn't HEAD and we're
 363          * not starting a new branch, and we want messages, and we
 364          * weren't on a branch, and we're moving to a new commit,
 365          * describe the old commit.
 366          */
 367         if (!new->path && strcmp(new->name, "HEAD") && !opts->new_branch &&
 368             !opts->quiet && !old.path && new->commit != old.commit)
 369                 describe_detached_head("Previous HEAD position was", old.commit);
 370
 371         if (!old.commit) {
 372                 if (!opts->quiet) {
 373                         fprintf(stderr, "warning: You appear to be on a branch yet to be born.\n");
 374                         fprintf(stderr, "warning: Forcing checkout of %s.\n", new->name);
 375                 }
 376                 opts->force = 1;
 377         }
 378
 379         ret = merge_working_tree(opts, &old, new, prefix);
 380         if (ret)
 381                 return ret;
 382
 383         update_refs_for_switch(opts, &old, new);
 384
 385         return post_checkout_hook(old.commit, new->commit, 1);
 386 }
 387
 388 static int branch_track = 0;
 389
 390 static int git_checkout_config(const char *var, const char *value)
 391 {
 392         if (!strcmp(var, "branch.autosetupmerge"))
 393                 branch_track = git_config_bool(var, value);
 394
 395         return git_default_config(var, value);
 396 }
 397
 398 int cmd_checkout(int argc, const char **argv, const char *prefix)
 399 {
 400         struct checkout_opts opts;
 401         unsigned char rev[20];
 402         const char *arg;
 403         struct branch_info new;
 404         struct tree *source_tree = NULL;
 405         struct option options[] = {
 406                 OPT__QUIET(&opts.quiet),
 407                 OPT_STRING('b', NULL, &opts.new_branch, "new branch", "branch"),
 408                 OPT_BOOLEAN('l', NULL, &opts.new_branch_log, "log for new branch"),
 409                 OPT_BOOLEAN( 0 , "track", &opts.track, "track"),
 410                 OPT_BOOLEAN('f', NULL, &opts.force, "force"),
 411                 OPT_BOOLEAN('m', NULL, &opts.merge, "merge"),
 412         };
 413
 414         memset(&opts, 0, sizeof(opts));
 415         memset(&new, 0, sizeof(new));
 416
 417         git_config(git_checkout_config);
 418
 419         opts.track = branch_track;
 420
 421         argc = parse_options(argc, argv, options, checkout_usage, 0);
 422         if (argc) {
 423                 arg = argv[0];
 424                 if (get_sha1(arg, rev))
 425                         ;
 426                 else if ((new.commit = lookup_commit_reference_gently(rev, 1))) {
 427                         new.name = arg;
 428                         setup_branch_path(&new);
 429                         if (resolve_ref(new.path, rev, 1, NULL))
 430                                 new.commit = lookup_commit_reference(rev);
 431                         else
 432                                 new.path = NULL;
 433                         parse_commit(new.commit);
 434                         source_tree = new.commit->tree;
 435                         argv++;
 436                         argc--;
 437                 } else if ((source_tree = parse_tree_indirect(rev))) {
 438                         argv++;
 439                         argc--;
 440                 }
 441         }
 442
 443         if (argc && !strcmp(argv[0], "--")) {
 444                 argv++;
 445                 argc--;
 446         }
 447
 448         if (!opts.new_branch && (opts.track != branch_track))
 449                 die("git checkout: --track and --no-track require -b");
 450
 451         if (opts.force && opts.merge)
 452                 die("git checkout: -f and -m are incompatible");
 453
 454         if (argc) {
 455                 const char **pathspec = get_pathspec(prefix, argv);
 456                 /* Checkout paths */
 457                 if (opts.new_branch || opts.force || opts.merge) {
 458                         if (argc == 1) {
 459                                 die("git checkout: updating paths is incompatible with switching branches/forcing\nDid you intend to checkout '%s' which can not be resolved as commit?", argv[0]);
 460                         } else {
 461                                 die("git checkout: updating paths is incompatible with switching branches/forcing");
 462                         }
 463                 }
 464
 465                 if (source_tree)
 466                         read_tree_some(source_tree, pathspec);
 467                 else
 468                         read_cache();
 469                 return checkout_paths(pathspec);
 470         }
 471
 472         if (new.name && !new.commit) {
 473                 die("Cannot switch branch to a non-commit.");
 474         }
 475
 476         return switch_branches(&opts, &new, prefix);
 477 }