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