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 static int post_checkout_hook(struct commit *old, struct commit *new,
  24                               int changed)
  25 {
  26         struct child_process proc;
  27         const char *name = git_path("hooks/post-checkout");
  28         const char *argv[5];
  29
  30         if (access(name, X_OK) < 0)
  31                 return 0;
  32
  33         memset(&proc, 0, sizeof(proc));
  34         argv[0] = name;
  35         argv[1] = xstrdup(sha1_to_hex(old->object.sha1));
  36         argv[2] = xstrdup(sha1_to_hex(new->object.sha1));
  37         argv[3] = changed ? "1" : "0";
  38         argv[4] = NULL;
  39         proc.argv = argv;
  40         proc.no_stdin = 1;
  41         proc.stdout_to_stderr = 1;
  42         return run_command(&proc);
  43 }
  44
  45 static int update_some(const unsigned char *sha1, const char *base, int baselen,
  46                        const char *pathname, unsigned mode, int stage)
  47 {
  48         int len;
  49         struct cache_entry *ce;
  50
  51         if (S_ISGITLINK(mode))
  52                 return 0;
  53
  54         if (S_ISDIR(mode))
  55                 return READ_TREE_RECURSIVE;
  56
  57         len = baselen + strlen(pathname);
  58         ce = xcalloc(1, cache_entry_size(len));
  59         hashcpy(ce->sha1, sha1);
  60         memcpy(ce->name, base, baselen);
  61         memcpy(ce->name + baselen, pathname, len - baselen);
  62         ce->ce_flags = create_ce_flags(len, 0);
  63         ce->ce_mode = create_ce_mode(mode);
  64         add_cache_entry(ce, ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
  65         return 0;
  66 }
  67
  68 static int read_tree_some(struct tree *tree, const char **pathspec)
  69 {
  70         read_tree_recursive(tree, "", 0, 0, pathspec, update_some);
  71
  72         /* update the index with the given tree's info
  73          * for all args, expanding wildcards, and exit
  74          * with any non-zero return code.
  75          */
  76         return 0;
  77 }
  78
  79 static int checkout_paths(struct tree *source_tree, const char **pathspec)
  80 {
  81         int pos;
  82         struct checkout state;
  83         static char *ps_matched;
  84         unsigned char rev[20];
  85         int flag;
  86         struct commit *head;
  87
  88         int newfd;
  89         struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
  90
  91         newfd = hold_locked_index(lock_file, 1);
  92         read_cache();
  93
  94         if (source_tree)
  95                 read_tree_some(source_tree, pathspec);
  96
  97         for (pos = 0; pathspec[pos]; pos++)
  98                 ;
  99         ps_matched = xcalloc(1, pos);
 100
 101         for (pos = 0; pos < active_nr; pos++) {
 102                 struct cache_entry *ce = active_cache[pos];
 103                 pathspec_match(pathspec, ps_matched, ce->name, 0);
 104         }
 105
 106         if (report_path_error(ps_matched, pathspec, 0))
 107                 return 1;
 108
 109         memset(&state, 0, sizeof(state));
 110         state.force = 1;
 111         state.refresh_cache = 1;
 112         for (pos = 0; pos < active_nr; pos++) {
 113                 struct cache_entry *ce = active_cache[pos];
 114                 if (pathspec_match(pathspec, NULL, ce->name, 0)) {
 115                         checkout_entry(ce, &state, NULL);
 116                 }
 117         }
 118
 119         if (write_cache(newfd, active_cache, active_nr) ||
 120             commit_locked_index(lock_file))
 121                 die("unable to write new index file");
 122
 123         resolve_ref("HEAD", rev, 0, &flag);
 124         head = lookup_commit_reference_gently(rev, 1);
 125
 126         return post_checkout_hook(head, head, 0);
 127 }
 128
 129 static void show_local_changes(struct object *head)
 130 {
 131         struct rev_info rev;
 132         /* I think we want full paths, even if we're in a subdirectory. */
 133         init_revisions(&rev, NULL);
 134         rev.abbrev = 0;
 135         rev.diffopt.output_format |= DIFF_FORMAT_NAME_STATUS;
 136         add_pending_object(&rev, head, NULL);
 137         run_diff_index(&rev, 0);
 138 }
 139
 140 static void describe_detached_head(char *msg, struct commit *commit)
 141 {
 142         struct strbuf sb;
 143         strbuf_init(&sb, 0);
 144         parse_commit(commit);
 145         pretty_print_commit(CMIT_FMT_ONELINE, commit, &sb, 0, NULL, NULL, 0, 0);
 146         fprintf(stderr, "%s %s... %s\n", msg,
 147                 find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV), sb.buf);
 148         strbuf_release(&sb);
 149 }
 150
 151 static int reset_to_new(struct tree *tree, int quiet)
 152 {
 153         struct unpack_trees_options opts;
 154         struct tree_desc tree_desc;
 155
 156         memset(&opts, 0, sizeof(opts));
 157         opts.head_idx = -1;
 158         opts.update = 1;
 159         opts.reset = 1;
 160         opts.merge = 1;
 161         opts.fn = oneway_merge;
 162         opts.verbose_update = !quiet;
 163         opts.src_index = &the_index;
 164         opts.dst_index = &the_index;
 165         parse_tree(tree);
 166         init_tree_desc(&tree_desc, tree->buffer, tree->size);
 167         if (unpack_trees(1, &tree_desc, &opts))
 168                 return 128;
 169         return 0;
 170 }
 171
 172 static void reset_clean_to_new(struct tree *tree, int quiet)
 173 {
 174         struct unpack_trees_options opts;
 175         struct tree_desc tree_desc;
 176
 177         memset(&opts, 0, sizeof(opts));
 178         opts.head_idx = -1;
 179         opts.skip_unmerged = 1;
 180         opts.reset = 1;
 181         opts.merge = 1;
 182         opts.fn = oneway_merge;
 183         opts.verbose_update = !quiet;
 184         opts.src_index = &the_index;
 185         opts.dst_index = &the_index;
 186         parse_tree(tree);
 187         init_tree_desc(&tree_desc, tree->buffer, tree->size);
 188         if (unpack_trees(1, &tree_desc, &opts))
 189                 exit(128);
 190 }
 191
 192 struct checkout_opts {
 193         int quiet;
 194         int merge;
 195         int force;
 196
 197         char *new_branch;
 198         int new_branch_log;
 199         enum branch_track track;
 200 };
 201
 202 struct branch_info {
 203         const char *name; /* The short name used */
 204         const char *path; /* The full name of a real branch */
 205         struct commit *commit; /* The named commit */
 206 };
 207
 208 static void setup_branch_path(struct branch_info *branch)
 209 {
 210         struct strbuf buf;
 211         strbuf_init(&buf, 0);
 212         strbuf_addstr(&buf, "refs/heads/");
 213         strbuf_addstr(&buf, branch->name);
 214         branch->path = strbuf_detach(&buf, NULL);
 215 }
 216
 217 static int merge_working_tree(struct checkout_opts *opts,
 218                               struct branch_info *old, struct branch_info *new)
 219 {
 220         int ret;
 221         struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
 222         int newfd = hold_locked_index(lock_file, 1);
 223         read_cache();
 224
 225         if (opts->force) {
 226                 ret = reset_to_new(new->commit->tree, opts->quiet);
 227                 if (ret)
 228                         return ret;
 229         } else {
 230                 struct tree_desc trees[2];
 231                 struct tree *tree;
 232                 struct unpack_trees_options topts;
 233
 234                 memset(&topts, 0, sizeof(topts));
 235                 topts.head_idx = -1;
 236                 topts.src_index = &the_index;
 237                 topts.dst_index = &the_index;
 238
 239                 topts.msgs.not_uptodate_file = "You have local changes to '%s'; cannot switch branches.";
 240
 241                 refresh_cache(REFRESH_QUIET);
 242
 243                 if (unmerged_cache()) {
 244                         error("you need to resolve your current index first");
 245                         return 1;
 246                 }
 247
 248                 /* 2-way merge to the new branch */
 249                 topts.update = 1;
 250                 topts.merge = 1;
 251                 topts.gently = opts->merge;
 252                 topts.verbose_update = !opts->quiet;
 253                 topts.fn = twoway_merge;
 254                 topts.dir = xcalloc(1, sizeof(*topts.dir));
 255                 topts.dir->show_ignored = 1;
 256                 topts.dir->exclude_per_dir = ".gitignore";
 257                 tree = parse_tree_indirect(old->commit->object.sha1);
 258                 init_tree_desc(&trees[0], tree->buffer, tree->size);
 259                 tree = parse_tree_indirect(new->commit->object.sha1);
 260                 init_tree_desc(&trees[1], tree->buffer, tree->size);
 261
 262                 if (unpack_trees(2, trees, &topts)) {
 263                         /*
 264                          * Unpack couldn't do a trivial merge; either
 265                          * give up or do a real merge, depending on
 266                          * whether the merge flag was used.
 267                          */
 268                         struct tree *result;
 269                         struct tree *work;
 270                         if (!opts->merge)
 271                                 return 1;
 272                         parse_commit(old->commit);
 273
 274                         /* Do more real merge */
 275
 276                         /*
 277                          * We update the index fully, then write the
 278                          * tree from the index, then merge the new
 279                          * branch with the current tree, with the old
 280                          * branch as the base. Then we reset the index
 281                          * (but not the working tree) to the new
 282                          * branch, leaving the working tree as the
 283                          * merged version, but skipping unmerged
 284                          * entries in the index.
 285                          */
 286
 287                         add_files_to_cache(NULL, NULL, 0);
 288                         work = write_tree_from_memory();
 289
 290                         ret = reset_to_new(new->commit->tree, opts->quiet);
 291                         if (ret)
 292                                 return ret;
 293                         merge_trees(new->commit->tree, work, old->commit->tree,
 294                                     new->name, "local", &result);
 295                         reset_clean_to_new(new->commit->tree, opts->quiet);
 296                 }
 297         }
 298
 299         if (write_cache(newfd, active_cache, active_nr) ||
 300             commit_locked_index(lock_file))
 301                 die("unable to write new index file");
 302
 303         if (!opts->force)
 304                 show_local_changes(&new->commit->object);
 305
 306         return 0;
 307 }
 308
 309 static void report_tracking(struct branch_info *new, struct checkout_opts *opts)
 310 {
 311         /*
 312          * We have switched to a new branch; is it building on
 313          * top of another branch, and if so does that other branch
 314          * have changes we do not have yet?
 315          */
 316         char *base;
 317         unsigned char sha1[20];
 318         struct commit *ours, *theirs;
 319         char symmetric[84];
 320         struct rev_info revs;
 321         const char *rev_argv[10];
 322         int rev_argc;
 323         int num_ours, num_theirs;
 324         const char *remote_msg;
 325         struct branch *branch = branch_get(new->name);
 326
 327         /*
 328          * Nothing to report unless we are marked to build on top of
 329          * somebody else.
 330          */
 331         if (!branch || !branch->merge || !branch->merge[0] || !branch->merge[0]->dst)
 332                 return;
 333
 334         /*
 335          * If what we used to build on no longer exists, there is
 336          * nothing to report.
 337          */
 338         base = branch->merge[0]->dst;
 339         if (!resolve_ref(base, sha1, 1, NULL))
 340                 return;
 341
 342         theirs = lookup_commit(sha1);
 343         ours = new->commit;
 344         if (!hashcmp(sha1, ours->object.sha1))
 345                 return; /* we are the same */
 346
 347         /* Run "rev-list --left-right ours...theirs" internally... */
 348         rev_argc = 0;
 349         rev_argv[rev_argc++] = NULL;
 350         rev_argv[rev_argc++] = "--left-right";
 351         rev_argv[rev_argc++] = symmetric;
 352         rev_argv[rev_argc++] = "--";
 353         rev_argv[rev_argc] = NULL;
 354
 355         strcpy(symmetric, sha1_to_hex(ours->object.sha1));
 356         strcpy(symmetric + 40, "...");
 357         strcpy(symmetric + 43, sha1_to_hex(theirs->object.sha1));
 358
 359         init_revisions(&revs, NULL);
 360         setup_revisions(rev_argc, rev_argv, &revs, NULL);
 361         prepare_revision_walk(&revs);
 362
 363         /* ... and count the commits on each side. */
 364         num_ours = 0;
 365         num_theirs = 0;
 366         while (1) {
 367                 struct commit *c = get_revision(&revs);
 368                 if (!c)
 369                         break;
 370                 if (c->object.flags & SYMMETRIC_LEFT)
 371                         num_ours++;
 372                 else
 373                         num_theirs++;
 374         }
 375
 376         if (!prefixcmp(base, "refs/remotes/")) {
 377                 remote_msg = " remote";
 378                 base += strlen("refs/remotes/");
 379         } else {
 380                 remote_msg = "";
 381         }
 382
 383         if (!num_theirs)
 384                 printf("Your branch is ahead of the tracked%s branch '%s' "
 385                        "by %d commit%s.\n",
 386                        remote_msg, base,
 387                        num_ours, (num_ours == 1) ? "" : "s");
 388         else if (!num_ours)
 389                 printf("Your branch is behind the tracked%s branch '%s' "
 390                        "by %d commit%s,\n"
 391                        "and can be fast-forwarded.\n",
 392                        remote_msg, base,
 393                        num_theirs, (num_theirs == 1) ? "" : "s");
 394         else
 395                 printf("Your branch and the tracked%s branch '%s' "
 396                        "have diverged,\nand respectively "
 397                        "have %d and %d different commit(s) each.\n",
 398                        remote_msg, base,
 399                        num_ours, num_theirs);
 400 }
 401
 402 static void update_refs_for_switch(struct checkout_opts *opts,
 403                                    struct branch_info *old,
 404                                    struct branch_info *new)
 405 {
 406         struct strbuf msg;
 407         const char *old_desc;
 408         if (opts->new_branch) {
 409                 create_branch(old->name, opts->new_branch, new->name, 0,
 410                               opts->new_branch_log, opts->track);
 411                 new->name = opts->new_branch;
 412                 setup_branch_path(new);
 413         }
 414
 415         strbuf_init(&msg, 0);
 416         old_desc = old->name;
 417         if (!old_desc)
 418                 old_desc = sha1_to_hex(old->commit->object.sha1);
 419         strbuf_addf(&msg, "checkout: moving from %s to %s",
 420                     old_desc, new->name);
 421
 422         if (new->path) {
 423                 create_symref("HEAD", new->path, msg.buf);
 424                 if (!opts->quiet) {
 425                         if (old->path && !strcmp(new->path, old->path))
 426                                 fprintf(stderr, "Already on \"%s\"\n",
 427                                         new->name);
 428                         else
 429                                 fprintf(stderr, "Switched to%s branch \"%s\"\n",
 430                                         opts->new_branch ? " a new" : "",
 431                                         new->name);
 432                 }
 433         } else if (strcmp(new->name, "HEAD")) {
 434                 update_ref(msg.buf, "HEAD", new->commit->object.sha1, NULL,
 435                            REF_NODEREF, DIE_ON_ERR);
 436                 if (!opts->quiet) {
 437                         if (old->path)
 438                                 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);
 439                         describe_detached_head("HEAD is now at", new->commit);
 440                 }
 441         }
 442         remove_branch_state();
 443         strbuf_release(&msg);
 444         if (!opts->quiet && (new->path || !strcmp(new->name, "HEAD")))
 445                 report_tracking(new, opts);
 446 }
 447
 448 static int switch_branches(struct checkout_opts *opts, struct branch_info *new)
 449 {
 450         int ret = 0;
 451         struct branch_info old;
 452         unsigned char rev[20];
 453         int flag;
 454         memset(&old, 0, sizeof(old));
 455         old.path = resolve_ref("HEAD", rev, 0, &flag);
 456         old.commit = lookup_commit_reference_gently(rev, 1);
 457         if (!(flag & REF_ISSYMREF))
 458                 old.path = NULL;
 459
 460         if (old.path && !prefixcmp(old.path, "refs/heads/"))
 461                 old.name = old.path + strlen("refs/heads/");
 462
 463         if (!new->name) {
 464                 new->name = "HEAD";
 465                 new->commit = old.commit;
 466                 if (!new->commit)
 467                         die("You are on a branch yet to be born");
 468                 parse_commit(new->commit);
 469         }
 470
 471         /*
 472          * If the new thing isn't a branch and isn't HEAD and we're
 473          * not starting a new branch, and we want messages, and we
 474          * weren't on a branch, and we're moving to a new commit,
 475          * describe the old commit.
 476          */
 477         if (!new->path && strcmp(new->name, "HEAD") && !opts->new_branch &&
 478             !opts->quiet && !old.path && new->commit != old.commit)
 479                 describe_detached_head("Previous HEAD position was", old.commit);
 480
 481         if (!old.commit) {
 482                 if (!opts->quiet) {
 483                         fprintf(stderr, "warning: You appear to be on a branch yet to be born.\n");
 484                         fprintf(stderr, "warning: Forcing checkout of %s.\n", new->name);
 485                 }
 486                 opts->force = 1;
 487         }
 488
 489         ret = merge_working_tree(opts, &old, new);
 490         if (ret)
 491                 return ret;
 492
 493         update_refs_for_switch(opts, &old, new);
 494
 495         return post_checkout_hook(old.commit, new->commit, 1);
 496 }
 497
 498 int cmd_checkout(int argc, const char **argv, const char *prefix)
 499 {
 500         struct checkout_opts opts;
 501         unsigned char rev[20];
 502         const char *arg;
 503         struct branch_info new;
 504         struct tree *source_tree = NULL;
 505         struct option options[] = {
 506                 OPT__QUIET(&opts.quiet),
 507                 OPT_STRING('b', NULL, &opts.new_branch, "new branch", "branch"),
 508                 OPT_BOOLEAN('l', NULL, &opts.new_branch_log, "log for new branch"),
 509                 OPT_SET_INT('t', "track",  &opts.track, "track",
 510                         BRANCH_TRACK_EXPLICIT),
 511                 OPT_BOOLEAN('f', NULL, &opts.force, "force"),
 512                 OPT_BOOLEAN('m', NULL, &opts.merge, "merge"),
 513                 OPT_END(),
 514         };
 515
 516         memset(&opts, 0, sizeof(opts));
 517         memset(&new, 0, sizeof(new));
 518
 519         git_config(git_default_config);
 520
 521         opts.track = git_branch_track;
 522
 523         argc = parse_options(argc, argv, options, checkout_usage, 0);
 524         if (argc) {
 525                 arg = argv[0];
 526                 if (get_sha1(arg, rev))
 527                         ;
 528                 else if ((new.commit = lookup_commit_reference_gently(rev, 1))) {
 529                         new.name = arg;
 530                         setup_branch_path(&new);
 531                         if (resolve_ref(new.path, rev, 1, NULL))
 532                                 new.commit = lookup_commit_reference(rev);
 533                         else
 534                                 new.path = NULL;
 535                         parse_commit(new.commit);
 536                         source_tree = new.commit->tree;
 537                         argv++;
 538                         argc--;
 539                 } else if ((source_tree = parse_tree_indirect(rev))) {
 540                         argv++;
 541                         argc--;
 542                 }
 543         }
 544
 545         if (argc && !strcmp(argv[0], "--")) {
 546                 argv++;
 547                 argc--;
 548         }
 549
 550         if (!opts.new_branch && (opts.track != git_branch_track))
 551                 die("git checkout: --track and --no-track require -b");
 552
 553         if (opts.force && opts.merge)
 554                 die("git checkout: -f and -m are incompatible");
 555
 556         if (argc) {
 557                 const char **pathspec = get_pathspec(prefix, argv);
 558
 559                 if (!pathspec)
 560                         die("invalid path specification");
 561
 562                 /* Checkout paths */
 563                 if (opts.new_branch || opts.force || opts.merge) {
 564                         if (argc == 1) {
 565                                 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]);
 566                         } else {
 567                                 die("git checkout: updating paths is incompatible with switching branches/forcing");
 568                         }
 569                 }
 570
 571                 return checkout_paths(source_tree, pathspec);
 572         }
 573
 574         if (new.name && !new.commit) {
 575                 die("Cannot switch branch to a non-commit.");
 576         }
 577
 578         return switch_branches(&opts, &new);
 579 }