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         int 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                               const char *prefix)
 210 {
 211         int ret;
 212         struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
 213         int newfd = hold_locked_index(lock_file, 1);
 214         read_cache();
 215
 216         if (opts->force) {
 217                 ret = reset_to_new(new->commit->tree, opts->quiet);
 218                 if (ret)
 219                         return ret;
 220         } else {
 221                 struct tree_desc trees[2];
 222                 struct tree *tree;
 223                 struct unpack_trees_options topts;
 224                 memset(&topts, 0, sizeof(topts));
 225                 topts.head_idx = -1;
 226
 227                 refresh_cache(REFRESH_QUIET);
 228
 229                 if (unmerged_cache()) {
 230                         ret = opts->merge ? -1 :
 231                                 error("you need to resolve your current index first");
 232                 } else {
 233                         topts.update = 1;
 234                         topts.merge = 1;
 235                         topts.gently = opts->merge;
 236                         topts.fn = twoway_merge;
 237                         topts.dir = xcalloc(1, sizeof(*topts.dir));
 238                         topts.dir->show_ignored = 1;
 239                         topts.dir->exclude_per_dir = ".gitignore";
 240                         topts.prefix = prefix;
 241                         tree = parse_tree_indirect(old->commit->object.sha1);
 242                         init_tree_desc(&trees[0], tree->buffer, tree->size);
 243                         tree = parse_tree_indirect(new->commit->object.sha1);
 244                         init_tree_desc(&trees[1], tree->buffer, tree->size);
 245                         ret = unpack_trees(2, trees, &topts);
 246                 }
 247                 if (ret) {
 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 /*
 295  * We really should allow cb_data... Yuck
 296  */
 297 static const char *branch_name;
 298 static int branch_name_len;
 299 static char *found_remote;
 300 static char *found_merge;
 301 static int read_branch_config(const char *var, const char *value)
 302 {
 303         const char *name;
 304         if (prefixcmp(var, "branch."))
 305                 return 0; /* not ours */
 306         name = var + strlen("branch.");
 307         if (strncmp(name, branch_name, branch_name_len) ||
 308             name[branch_name_len] != '.')
 309                 return 0; /* not ours either */
 310         if (!strcmp(name + branch_name_len, ".remote")) {
 311                 /*
 312                  * Yeah, I know Christian's clean-up should
 313                  * be used here, but the topic is based on an
 314                  * older fork point.
 315                  */
 316                 if (!value)
 317                         return error("'%s' not string", var);
 318                 found_remote = xstrdup(value);
 319                 return 0;
 320         }
 321         if (!strcmp(name + branch_name_len, ".merge")) {
 322                 if (!value)
 323                         return error("'%s' not string", var);
 324                 found_merge = xstrdup(value);
 325                 return 0;
 326         }
 327         return 0; /* not ours */
 328 }
 329
 330 static int find_build_base(const char *ours, char **base)
 331 {
 332         struct remote *remote;
 333         struct refspec spec;
 334
 335         *base = NULL;
 336
 337         branch_name = ours + strlen("refs/heads/");
 338         branch_name_len = strlen(branch_name);
 339         found_remote = NULL;
 340         found_merge = NULL;
 341         git_config(read_branch_config);
 342
 343         if (!found_remote || !found_merge) {
 344         cleanup:
 345                 free(found_remote);
 346                 free(found_merge);
 347                 return 0;
 348         }
 349
 350         remote = remote_get(found_remote);
 351         memset(&spec, 0, sizeof(spec));
 352         spec.src = found_merge;
 353         if (remote_find_tracking(remote, &spec))
 354                 goto cleanup;
 355         *base = spec.dst;
 356         return 1;
 357 }
 358
 359 static void adjust_to_tracking(struct branch_info *new, struct checkout_opts *opts)
 360 {
 361         /*
 362          * We have switched to a new branch; is it building on
 363          * top of another branch, and if so does that other branch
 364          * have changes we do not have yet?
 365          */
 366         char *base;
 367         unsigned char sha1[20];
 368         struct commit *ours, *theirs;
 369         const char *msgfmt;
 370         char symmetric[84];
 371         int show_log;
 372
 373         if (!resolve_ref(new->path, sha1, 1, NULL))
 374                 return;
 375         ours = lookup_commit(sha1);
 376
 377         if (!find_build_base(new->path, &base))
 378                 return;
 379
 380         sprintf(symmetric, "%s", sha1_to_hex(sha1));
 381
 382         /*
 383          * Ok, it is tracking base; is it ahead of us?
 384          */
 385         if (!resolve_ref(base, sha1, 1, NULL))
 386                 return;
 387         theirs = lookup_commit(sha1);
 388
 389         sprintf(symmetric + 40, "...%s", sha1_to_hex(sha1));
 390
 391         if (!hashcmp(sha1, ours->object.sha1))
 392                 return; /* we are the same */
 393
 394         show_log = 1;
 395         if (in_merge_bases(theirs, &ours, 1)) {
 396                 msgfmt = "You are ahead of the tracked branch '%s'\n";
 397                 show_log = 0;
 398         }
 399         else if (in_merge_bases(ours, &theirs, 1))
 400                 msgfmt = "Your branch can be fast-forwarded to the tracked branch '%s'\n";
 401         else
 402                 msgfmt = "Both your branch and the tracked branch '%s' have own changes, you would eventually need to merge\n";
 403
 404         if (!prefixcmp(base, "refs/remotes/"))
 405                 base += strlen("refs/remotes/");
 406         fprintf(stderr, msgfmt, base);
 407
 408         if (show_log) {
 409                 const char *args[32];
 410                 int ac;
 411
 412                 ac = 0;
 413                 args[ac++] = "log";
 414                 args[ac++] = "--pretty=oneline";
 415                 args[ac++] = "--abbrev-commit";
 416                 args[ac++] = "--left-right";
 417                 args[ac++] = "--boundary";
 418                 args[ac++] = symmetric;
 419                 args[ac++] = "--";
 420                 args[ac] = NULL;
 421
 422                 run_command_v_opt(args, RUN_GIT_CMD);
 423         }
 424 }
 425
 426
 427 static void update_refs_for_switch(struct checkout_opts *opts,
 428                                    struct branch_info *old,
 429                                    struct branch_info *new)
 430 {
 431         struct strbuf msg;
 432         const char *old_desc;
 433         if (opts->new_branch) {
 434                 create_branch(old->name, opts->new_branch, new->name, 0,
 435                               opts->new_branch_log, opts->track);
 436                 new->name = opts->new_branch;
 437                 setup_branch_path(new);
 438         }
 439
 440         strbuf_init(&msg, 0);
 441         old_desc = old->name;
 442         if (!old_desc)
 443                 old_desc = sha1_to_hex(old->commit->object.sha1);
 444         strbuf_addf(&msg, "checkout: moving from %s to %s",
 445                     old_desc, new->name);
 446
 447         if (new->path) {
 448                 create_symref("HEAD", new->path, msg.buf);
 449                 if (!opts->quiet) {
 450                         if (old->path && !strcmp(new->path, old->path))
 451                                 fprintf(stderr, "Already on \"%s\"\n",
 452                                         new->name);
 453                         else
 454                                 fprintf(stderr, "Switched to%s branch \"%s\"\n",
 455                                         opts->new_branch ? " a new" : "",
 456                                         new->name);
 457                 }
 458         } else if (strcmp(new->name, "HEAD")) {
 459                 update_ref(msg.buf, "HEAD", new->commit->object.sha1, NULL,
 460                            REF_NODEREF, DIE_ON_ERR);
 461                 if (!opts->quiet) {
 462                         if (old->path)
 463                                 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);
 464                         describe_detached_head("HEAD is now at", new->commit);
 465                 }
 466         }
 467         remove_branch_state();
 468         strbuf_release(&msg);
 469         if (new->path)
 470                 adjust_to_tracking(new, opts);
 471 }
 472
 473 static int switch_branches(struct checkout_opts *opts,
 474                            struct branch_info *new, const char *prefix)
 475 {
 476         int ret = 0;
 477         struct branch_info old;
 478         unsigned char rev[20];
 479         int flag;
 480         memset(&old, 0, sizeof(old));
 481         old.path = resolve_ref("HEAD", rev, 0, &flag);
 482         old.commit = lookup_commit_reference_gently(rev, 1);
 483         if (!(flag & REF_ISSYMREF))
 484                 old.path = NULL;
 485
 486         if (old.path && !prefixcmp(old.path, "refs/heads/"))
 487                 old.name = old.path + strlen("refs/heads/");
 488
 489         if (!new->name) {
 490                 new->name = "HEAD";
 491                 new->commit = old.commit;
 492                 if (!new->commit)
 493                         die("You are on a branch yet to be born");
 494                 parse_commit(new->commit);
 495         }
 496
 497         /*
 498          * If the new thing isn't a branch and isn't HEAD and we're
 499          * not starting a new branch, and we want messages, and we
 500          * weren't on a branch, and we're moving to a new commit,
 501          * describe the old commit.
 502          */
 503         if (!new->path && strcmp(new->name, "HEAD") && !opts->new_branch &&
 504             !opts->quiet && !old.path && new->commit != old.commit)
 505                 describe_detached_head("Previous HEAD position was", old.commit);
 506
 507         if (!old.commit) {
 508                 if (!opts->quiet) {
 509                         fprintf(stderr, "warning: You appear to be on a branch yet to be born.\n");
 510                         fprintf(stderr, "warning: Forcing checkout of %s.\n", new->name);
 511                 }
 512                 opts->force = 1;
 513         }
 514
 515         ret = merge_working_tree(opts, &old, new, prefix);
 516         if (ret)
 517                 return ret;
 518
 519         update_refs_for_switch(opts, &old, new);
 520
 521         return post_checkout_hook(old.commit, new->commit, 1);
 522 }
 523
 524 static int branch_track = 0;
 525
 526 static int git_checkout_config(const char *var, const char *value)
 527 {
 528         if (!strcmp(var, "branch.autosetupmerge"))
 529                 branch_track = git_config_bool(var, value);
 530
 531         return git_default_config(var, value);
 532 }
 533
 534 int cmd_checkout(int argc, const char **argv, const char *prefix)
 535 {
 536         struct checkout_opts opts;
 537         unsigned char rev[20];
 538         const char *arg;
 539         struct branch_info new;
 540         struct tree *source_tree = NULL;
 541         struct option options[] = {
 542                 OPT__QUIET(&opts.quiet),
 543                 OPT_STRING('b', NULL, &opts.new_branch, "new branch", "branch"),
 544                 OPT_BOOLEAN('l', NULL, &opts.new_branch_log, "log for new branch"),
 545                 OPT_BOOLEAN( 0 , "track", &opts.track, "track"),
 546                 OPT_BOOLEAN('f', NULL, &opts.force, "force"),
 547                 OPT_BOOLEAN('m', NULL, &opts.merge, "merge"),
 548                 OPT_END(),
 549         };
 550
 551         memset(&opts, 0, sizeof(opts));
 552         memset(&new, 0, sizeof(new));
 553
 554         git_config(git_checkout_config);
 555
 556         opts.track = branch_track;
 557
 558         argc = parse_options(argc, argv, options, checkout_usage, 0);
 559         if (argc) {
 560                 arg = argv[0];
 561                 if (get_sha1(arg, rev))
 562                         ;
 563                 else if ((new.commit = lookup_commit_reference_gently(rev, 1))) {
 564                         new.name = arg;
 565                         setup_branch_path(&new);
 566                         if (resolve_ref(new.path, rev, 1, NULL))
 567                                 new.commit = lookup_commit_reference(rev);
 568                         else
 569                                 new.path = NULL;
 570                         parse_commit(new.commit);
 571                         source_tree = new.commit->tree;
 572                         argv++;
 573                         argc--;
 574                 } else if ((source_tree = parse_tree_indirect(rev))) {
 575                         argv++;
 576                         argc--;
 577                 }
 578         }
 579
 580         if (argc && !strcmp(argv[0], "--")) {
 581                 argv++;
 582                 argc--;
 583         }
 584
 585         if (!opts.new_branch && (opts.track != branch_track))
 586                 die("git checkout: --track and --no-track require -b");
 587
 588         if (opts.force && opts.merge)
 589                 die("git checkout: -f and -m are incompatible");
 590
 591         if (argc) {
 592                 const char **pathspec = get_pathspec(prefix, argv);
 593                 /* Checkout paths */
 594                 if (opts.new_branch || opts.force || opts.merge) {
 595                         if (argc == 1) {
 596                                 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]);
 597                         } else {
 598                                 die("git checkout: updating paths is incompatible with switching branches/forcing");
 599                         }
 600                 }
 601
 602                 if (source_tree)
 603                         read_tree_some(source_tree, pathspec);
 604                 else
 605                         read_cache();
 606                 return checkout_paths(pathspec);
 607         }
 608
 609         if (new.name && !new.commit) {
 610                 die("Cannot switch branch to a non-commit.");
 611         }
 612
 613         return switch_branches(&opts, &new, prefix);
 614 }