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 #include "remote.h"
  16
  17 static const char * const checkout_usage[] = {
  18         "git checkout [options] <branch>",
  19         "git checkout [options] [<branch>] -- <file>...",
  20         NULL,
  21 };
  22
  23 struct checkout_opts {
  24         int quiet;
  25         int merge;
  26         int force;
  27         int writeout_error;
  28
  29         const char *new_branch;
  30         int new_branch_log;
  31         enum branch_track track;
  32 };
  33
  34 static int post_checkout_hook(struct commit *old, struct commit *new,
  35                               int changed)
  36 {
  37         struct child_process proc;
  38         const char *name = git_path("hooks/post-checkout");
  39         const char *argv[5];
  40
  41         if (access(name, X_OK) < 0)
  42                 return 0;
  43
  44         memset(&proc, 0, sizeof(proc));
  45         argv[0] = name;
  46         argv[1] = xstrdup(sha1_to_hex(old->object.sha1));
  47         argv[2] = xstrdup(sha1_to_hex(new->object.sha1));
  48         argv[3] = changed ? "1" : "0";
  49         argv[4] = NULL;
  50         proc.argv = argv;
  51         proc.no_stdin = 1;
  52         proc.stdout_to_stderr = 1;
  53         return run_command(&proc);
  54 }
  55
  56 static int update_some(const unsigned char *sha1, const char *base, int baselen,
  57                 const char *pathname, unsigned mode, int stage, void *context)
  58 {
  59         int len;
  60         struct cache_entry *ce;
  61
  62         if (S_ISGITLINK(mode))
  63                 return 0;
  64
  65         if (S_ISDIR(mode))
  66                 return READ_TREE_RECURSIVE;
  67
  68         len = baselen + strlen(pathname);
  69         ce = xcalloc(1, cache_entry_size(len));
  70         hashcpy(ce->sha1, sha1);
  71         memcpy(ce->name, base, baselen);
  72         memcpy(ce->name + baselen, pathname, len - baselen);
  73         ce->ce_flags = create_ce_flags(len, 0);
  74         ce->ce_mode = create_ce_mode(mode);
  75         add_cache_entry(ce, ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
  76         return 0;
  77 }
  78
  79 static int read_tree_some(struct tree *tree, const char **pathspec)
  80 {
  81         read_tree_recursive(tree, "", 0, 0, pathspec, update_some, NULL);
  82
  83         /* update the index with the given tree's info
  84          * for all args, expanding wildcards, and exit
  85          * with any non-zero return code.
  86          */
  87         return 0;
  88 }
  89
  90 static int skip_same_name(struct cache_entry *ce, int pos)
  91 {
  92         while (++pos < active_nr &&
  93                !strcmp(active_cache[pos]->name, ce->name))
  94                 ; /* skip */
  95         return pos;
  96 }
  97
  98
  99 static int checkout_paths(struct tree *source_tree, const char **pathspec,
 100                           struct checkout_opts *opts)
 101 {
 102         int pos;
 103         struct checkout state;
 104         static char *ps_matched;
 105         unsigned char rev[20];
 106         int flag;
 107         struct commit *head;
 108         int errs = 0;
 109
 110         int newfd;
 111         struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
 112
 113         newfd = hold_locked_index(lock_file, 1);
 114         read_cache();
 115
 116         if (source_tree)
 117                 read_tree_some(source_tree, pathspec);
 118
 119         for (pos = 0; pathspec[pos]; pos++)
 120                 ;
 121         ps_matched = xcalloc(1, pos);
 122
 123         for (pos = 0; pos < active_nr; pos++) {
 124                 struct cache_entry *ce = active_cache[pos];
 125                 pathspec_match(pathspec, ps_matched, ce->name, 0);
 126         }
 127
 128         if (report_path_error(ps_matched, pathspec, 0))
 129                 return 1;
 130
 131         /* Any unmerged paths? */
 132         for (pos = 0; pos < active_nr; pos++) {
 133                 struct cache_entry *ce = active_cache[pos];
 134                 if (pathspec_match(pathspec, NULL, ce->name, 0)) {
 135                         if (!ce_stage(ce))
 136                                 continue;
 137                         if (opts->force) {
 138                                 warning("path '%s' is unmerged", ce->name);
 139                         } else {
 140                                 errs = 1;
 141                                 error("path '%s' is unmerged", ce->name);
 142                         }
 143                         pos = skip_same_name(ce, pos) - 1;
 144                 }
 145         }
 146         if (errs)
 147                 return 1;
 148
 149         /* Now we are committed to check them out */
 150         memset(&state, 0, sizeof(state));
 151         state.force = 1;
 152         state.refresh_cache = 1;
 153         for (pos = 0; pos < active_nr; pos++) {
 154                 struct cache_entry *ce = active_cache[pos];
 155                 if (pathspec_match(pathspec, NULL, ce->name, 0)) {
 156                         if (!ce_stage(ce)) {
 157                                 errs |= checkout_entry(ce, &state, NULL);
 158                                 continue;
 159                         }
 160                         pos = skip_same_name(ce, pos) - 1;
 161                 }
 162         }
 163
 164         if (write_cache(newfd, active_cache, active_nr) ||
 165             commit_locked_index(lock_file))
 166                 die("unable to write new index file");
 167
 168         resolve_ref("HEAD", rev, 0, &flag);
 169         head = lookup_commit_reference_gently(rev, 1);
 170
 171         errs |= post_checkout_hook(head, head, 0);
 172         return errs;
 173 }
 174
 175 static void show_local_changes(struct object *head)
 176 {
 177         struct rev_info rev;
 178         /* I think we want full paths, even if we're in a subdirectory. */
 179         init_revisions(&rev, NULL);
 180         rev.abbrev = 0;
 181         rev.diffopt.output_format |= DIFF_FORMAT_NAME_STATUS;
 182         add_pending_object(&rev, head, NULL);
 183         run_diff_index(&rev, 0);
 184 }
 185
 186 static void describe_detached_head(char *msg, struct commit *commit)
 187 {
 188         struct strbuf sb;
 189         strbuf_init(&sb, 0);
 190         parse_commit(commit);
 191         pretty_print_commit(CMIT_FMT_ONELINE, commit, &sb, 0, NULL, NULL, 0, 0);
 192         fprintf(stderr, "%s %s... %s\n", msg,
 193                 find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV), sb.buf);
 194         strbuf_release(&sb);
 195 }
 196
 197 static int reset_tree(struct tree *tree, struct checkout_opts *o, int worktree)
 198 {
 199         struct unpack_trees_options opts;
 200         struct tree_desc tree_desc;
 201
 202         memset(&opts, 0, sizeof(opts));
 203         opts.head_idx = -1;
 204         opts.update = worktree;
 205         opts.skip_unmerged = !worktree;
 206         opts.reset = 1;
 207         opts.merge = 1;
 208         opts.fn = oneway_merge;
 209         opts.verbose_update = !o->quiet;
 210         opts.src_index = &the_index;
 211         opts.dst_index = &the_index;
 212         parse_tree(tree);
 213         init_tree_desc(&tree_desc, tree->buffer, tree->size);
 214         switch (unpack_trees(1, &tree_desc, &opts)) {
 215         case -2:
 216                 o->writeout_error = 1;
 217                 /*
 218                  * We return 0 nevertheless, as the index is all right
 219                  * and more importantly we have made best efforts to
 220                  * update paths in the work tree, and we cannot revert
 221                  * them.
 222                  */
 223         case 0:
 224                 return 0;
 225         default:
 226                 return 128;
 227         }
 228 }
 229
 230 struct branch_info {
 231         const char *name; /* The short name used */
 232         const char *path; /* The full name of a real branch */
 233         struct commit *commit; /* The named commit */
 234 };
 235
 236 static void setup_branch_path(struct branch_info *branch)
 237 {
 238         struct strbuf buf;
 239         strbuf_init(&buf, 0);
 240         strbuf_addstr(&buf, "refs/heads/");
 241         strbuf_addstr(&buf, branch->name);
 242         branch->path = strbuf_detach(&buf, NULL);
 243 }
 244
 245 static int merge_working_tree(struct checkout_opts *opts,
 246                               struct branch_info *old, struct branch_info *new)
 247 {
 248         int ret;
 249         struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
 250         int newfd = hold_locked_index(lock_file, 1);
 251         read_cache();
 252
 253         if (opts->force) {
 254                 ret = reset_tree(new->commit->tree, opts, 1);
 255                 if (ret)
 256                         return ret;
 257         } else {
 258                 struct tree_desc trees[2];
 259                 struct tree *tree;
 260                 struct unpack_trees_options topts;
 261
 262                 memset(&topts, 0, sizeof(topts));
 263                 topts.head_idx = -1;
 264                 topts.src_index = &the_index;
 265                 topts.dst_index = &the_index;
 266
 267                 topts.msgs.not_uptodate_file = "You have local changes to '%s'; cannot switch branches.";
 268
 269                 refresh_cache(REFRESH_QUIET);
 270
 271                 if (unmerged_cache()) {
 272                         error("you need to resolve your current index first");
 273                         return 1;
 274                 }
 275
 276                 /* 2-way merge to the new branch */
 277                 topts.update = 1;
 278                 topts.merge = 1;
 279                 topts.gently = opts->merge;
 280                 topts.verbose_update = !opts->quiet;
 281                 topts.fn = twoway_merge;
 282                 topts.dir = xcalloc(1, sizeof(*topts.dir));
 283                 topts.dir->show_ignored = 1;
 284                 topts.dir->exclude_per_dir = ".gitignore";
 285                 tree = parse_tree_indirect(old->commit->object.sha1);
 286                 init_tree_desc(&trees[0], tree->buffer, tree->size);
 287                 tree = parse_tree_indirect(new->commit->object.sha1);
 288                 init_tree_desc(&trees[1], tree->buffer, tree->size);
 289
 290                 ret = unpack_trees(2, trees, &topts);
 291                 if (ret == -1) {
 292                         /*
 293                          * Unpack couldn't do a trivial merge; either
 294                          * give up or do a real merge, depending on
 295                          * whether the merge flag was used.
 296                          */
 297                         struct tree *result;
 298                         struct tree *work;
 299                         if (!opts->merge)
 300                                 return 1;
 301                         parse_commit(old->commit);
 302
 303                         /* Do more real merge */
 304
 305                         /*
 306                          * We update the index fully, then write the
 307                          * tree from the index, then merge the new
 308                          * branch with the current tree, with the old
 309                          * branch as the base. Then we reset the index
 310                          * (but not the working tree) to the new
 311                          * branch, leaving the working tree as the
 312                          * merged version, but skipping unmerged
 313                          * entries in the index.
 314                          */
 315
 316                         add_files_to_cache(NULL, NULL, 0);
 317                         work = write_tree_from_memory();
 318
 319                         ret = reset_tree(new->commit->tree, opts, 1);
 320                         if (ret)
 321                                 return ret;
 322                         merge_trees(new->commit->tree, work, old->commit->tree,
 323                                     new->name, "local", &result);
 324                         ret = reset_tree(new->commit->tree, opts, 0);
 325                         if (ret)
 326                                 return ret;
 327                 }
 328         }
 329
 330         if (write_cache(newfd, active_cache, active_nr) ||
 331             commit_locked_index(lock_file))
 332                 die("unable to write new index file");
 333
 334         if (!opts->force)
 335                 show_local_changes(&new->commit->object);
 336
 337         return 0;
 338 }
 339
 340 static void report_tracking(struct branch_info *new)
 341 {
 342         struct strbuf sb = STRBUF_INIT;
 343         struct branch *branch = branch_get(new->name);
 344
 345         if (!format_tracking_info(branch, &sb))
 346                 return;
 347         fputs(sb.buf, stdout);
 348         strbuf_release(&sb);
 349 }
 350
 351 static void update_refs_for_switch(struct checkout_opts *opts,
 352                                    struct branch_info *old,
 353                                    struct branch_info *new)
 354 {
 355         struct strbuf msg;
 356         const char *old_desc;
 357         if (opts->new_branch) {
 358                 create_branch(old->name, opts->new_branch, new->name, 0,
 359                               opts->new_branch_log, opts->track);
 360                 new->name = opts->new_branch;
 361                 setup_branch_path(new);
 362         }
 363
 364         strbuf_init(&msg, 0);
 365         old_desc = old->name;
 366         if (!old_desc)
 367                 old_desc = sha1_to_hex(old->commit->object.sha1);
 368         strbuf_addf(&msg, "checkout: moving from %s to %s",
 369                     old_desc, new->name);
 370
 371         if (new->path) {
 372                 create_symref("HEAD", new->path, msg.buf);
 373                 if (!opts->quiet) {
 374                         if (old->path && !strcmp(new->path, old->path))
 375                                 fprintf(stderr, "Already on \"%s\"\n",
 376                                         new->name);
 377                         else
 378                                 fprintf(stderr, "Switched to%s branch \"%s\"\n",
 379                                         opts->new_branch ? " a new" : "",
 380                                         new->name);
 381                 }
 382         } else if (strcmp(new->name, "HEAD")) {
 383                 update_ref(msg.buf, "HEAD", new->commit->object.sha1, NULL,
 384                            REF_NODEREF, DIE_ON_ERR);
 385                 if (!opts->quiet) {
 386                         if (old->path)
 387                                 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);
 388                         describe_detached_head("HEAD is now at", new->commit);
 389                 }
 390         }
 391         remove_branch_state();
 392         strbuf_release(&msg);
 393         if (!opts->quiet && (new->path || !strcmp(new->name, "HEAD")))
 394                 report_tracking(new);
 395 }
 396
 397 static int switch_branches(struct checkout_opts *opts, struct branch_info *new)
 398 {
 399         int ret = 0;
 400         struct branch_info old;
 401         unsigned char rev[20];
 402         int flag;
 403         memset(&old, 0, sizeof(old));
 404         old.path = resolve_ref("HEAD", rev, 0, &flag);
 405         old.commit = lookup_commit_reference_gently(rev, 1);
 406         if (!(flag & REF_ISSYMREF))
 407                 old.path = NULL;
 408
 409         if (old.path && !prefixcmp(old.path, "refs/heads/"))
 410                 old.name = old.path + strlen("refs/heads/");
 411
 412         if (!new->name) {
 413                 new->name = "HEAD";
 414                 new->commit = old.commit;
 415                 if (!new->commit)
 416                         die("You are on a branch yet to be born");
 417                 parse_commit(new->commit);
 418         }
 419
 420         /*
 421          * If the new thing isn't a branch and isn't HEAD and we're
 422          * not starting a new branch, and we want messages, and we
 423          * weren't on a branch, and we're moving to a new commit,
 424          * describe the old commit.
 425          */
 426         if (!new->path && strcmp(new->name, "HEAD") && !opts->new_branch &&
 427             !opts->quiet && !old.path && new->commit != old.commit)
 428                 describe_detached_head("Previous HEAD position was", old.commit);
 429
 430         if (!old.commit) {
 431                 if (!opts->quiet) {
 432                         fprintf(stderr, "warning: You appear to be on a branch yet to be born.\n");
 433                         fprintf(stderr, "warning: Forcing checkout of %s.\n", new->name);
 434                 }
 435                 opts->force = 1;
 436         }
 437
 438         ret = merge_working_tree(opts, &old, new);
 439         if (ret)
 440                 return ret;
 441
 442         update_refs_for_switch(opts, &old, new);
 443
 444         ret = post_checkout_hook(old.commit, new->commit, 1);
 445         return ret || opts->writeout_error;
 446 }
 447
 448 int cmd_checkout(int argc, const char **argv, const char *prefix)
 449 {
 450         struct checkout_opts opts;
 451         unsigned char rev[20];
 452         const char *arg;
 453         struct branch_info new;
 454         struct tree *source_tree = NULL;
 455         struct option options[] = {
 456                 OPT__QUIET(&opts.quiet),
 457                 OPT_STRING('b', NULL, &opts.new_branch, "new branch", "branch"),
 458                 OPT_BOOLEAN('l', NULL, &opts.new_branch_log, "log for new branch"),
 459                 OPT_SET_INT('t', "track",  &opts.track, "track",
 460                         BRANCH_TRACK_EXPLICIT),
 461                 OPT_BOOLEAN('f', NULL, &opts.force, "force"),
 462                 OPT_BOOLEAN('m', NULL, &opts.merge, "merge"),
 463                 OPT_END(),
 464         };
 465         int has_dash_dash;
 466
 467         memset(&opts, 0, sizeof(opts));
 468         memset(&new, 0, sizeof(new));
 469
 470         git_config(git_default_config, NULL);
 471
 472         opts.track = git_branch_track;
 473
 474         argc = parse_options(argc, argv, options, checkout_usage,
 475                              PARSE_OPT_KEEP_DASHDASH);
 476
 477         if (!opts.new_branch && (opts.track != git_branch_track))
 478                 die("git checkout: --track and --no-track require -b");
 479
 480         if (opts.force && opts.merge)
 481                 die("git checkout: -f and -m are incompatible");
 482
 483         /*
 484          * case 1: git checkout <ref> -- [<paths>]
 485          *
 486          *   <ref> must be a valid tree, everything after the '--' must be
 487          *   a path.
 488          *
 489          * case 2: git checkout -- [<paths>]
 490          *
 491          *   everything after the '--' must be paths.
 492          *
 493          * case 3: git checkout <something> [<paths>]
 494          *
 495          *   With no paths, if <something> is a commit, that is to
 496          *   switch to the branch or detach HEAD at it.
 497          *
 498          *   Otherwise <something> shall not be ambiguous.
 499          *   - If it's *only* a reference, treat it like case (1).
 500          *   - If it's only a path, treat it like case (2).
 501          *   - else: fail.
 502          *
 503          */
 504         if (argc) {
 505                 if (!strcmp(argv[0], "--")) {       /* case (2) */
 506                         argv++;
 507                         argc--;
 508                         goto no_reference;
 509                 }
 510
 511                 arg = argv[0];
 512                 has_dash_dash = (argc > 1) && !strcmp(argv[1], "--");
 513
 514                 if (get_sha1(arg, rev)) {
 515                         if (has_dash_dash)          /* case (1) */
 516                                 die("invalid reference: %s", arg);
 517                         goto no_reference;          /* case (3 -> 2) */
 518                 }
 519
 520                 /* we can't end up being in (2) anymore, eat the argument */
 521                 argv++;
 522                 argc--;
 523
 524                 if ((new.commit = lookup_commit_reference_gently(rev, 1))) {
 525                         new.name = arg;
 526                         setup_branch_path(&new);
 527                         if (resolve_ref(new.path, rev, 1, NULL))
 528                                 new.commit = lookup_commit_reference(rev);
 529                         else
 530                                 new.path = NULL;
 531                         parse_commit(new.commit);
 532                         source_tree = new.commit->tree;
 533                 } else
 534                         source_tree = parse_tree_indirect(rev);
 535
 536                 if (!source_tree)                   /* case (1): want a tree */
 537                         die("reference is not a tree: %s", arg);
 538                 if (!has_dash_dash) {/* case (3 -> 1) */
 539                         /*
 540                          * Do not complain the most common case
 541                          *      git checkout branch
 542                          * even if there happen to be a file called 'branch';
 543                          * it would be extremely annoying.
 544                          */
 545                         if (argc)
 546                                 verify_non_filename(NULL, arg);
 547                 }
 548                 else {
 549                         argv++;
 550                         argc--;
 551                 }
 552         }
 553
 554 no_reference:
 555         if (argc) {
 556                 const char **pathspec = get_pathspec(prefix, argv);
 557
 558                 if (!pathspec)
 559                         die("invalid path specification");
 560
 561                 /* Checkout paths */
 562                 if (opts.new_branch || opts.merge) {
 563                         if (argc == 1) {
 564                                 die("git checkout: updating paths is incompatible with switching branches.\nDid you intend to checkout '%s' which can not be resolved as commit?", argv[0]);
 565                         } else {
 566                                 die("git checkout: updating paths is incompatible with switching branches.");
 567                         }
 568                 }
 569
 570                 return checkout_paths(source_tree, pathspec, &opts);
 571         }
 572
 573         if (new.name && !new.commit) {
 574                 die("Cannot switch branch to a non-commit.");
 575         }
 576
 577         return switch_branches(&opts, &new);
 578 }