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, "", "", 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                 refresh_cache(REFRESH_QUIET);
 240
 241                 if (unmerged_cache()) {
 242                         error("you need to resolve your current index first");
 243                         return 1;
 244                 }
 245
 246                 /* 2-way merge to the new branch */
 247                 topts.update = 1;
 248                 topts.merge = 1;
 249                 topts.gently = opts->merge;
 250                 topts.verbose_update = !opts->quiet;
 251                 topts.fn = twoway_merge;
 252                 topts.dir = xcalloc(1, sizeof(*topts.dir));
 253                 topts.dir->show_ignored = 1;
 254                 topts.dir->exclude_per_dir = ".gitignore";
 255                 tree = parse_tree_indirect(old->commit->object.sha1);
 256                 init_tree_desc(&trees[0], tree->buffer, tree->size);
 257                 tree = parse_tree_indirect(new->commit->object.sha1);
 258                 init_tree_desc(&trees[1], tree->buffer, tree->size);
 259
 260                 if (unpack_trees(2, trees, &topts)) {
 261                         /*
 262                          * Unpack couldn't do a trivial merge; either
 263                          * give up or do a real merge, depending on
 264                          * whether the merge flag was used.
 265                          */
 266                         struct tree *result;
 267                         struct tree *work;
 268                         if (!opts->merge)
 269                                 return 1;
 270                         parse_commit(old->commit);
 271
 272                         /* Do more real merge */
 273
 274                         /*
 275                          * We update the index fully, then write the
 276                          * tree from the index, then merge the new
 277                          * branch with the current tree, with the old
 278                          * branch as the base. Then we reset the index
 279                          * (but not the working tree) to the new
 280                          * branch, leaving the working tree as the
 281                          * merged version, but skipping unmerged
 282                          * entries in the index.
 283                          */
 284
 285                         add_files_to_cache(0, NULL, NULL);
 286                         work = write_tree_from_memory();
 287
 288                         ret = reset_to_new(new->commit->tree, opts->quiet);
 289                         if (ret)
 290                                 return ret;
 291                         merge_trees(new->commit->tree, work, old->commit->tree,
 292                                     new->name, "local", &result);
 293                         reset_clean_to_new(new->commit->tree, opts->quiet);
 294                 }
 295         }
 296
 297         if (write_cache(newfd, active_cache, active_nr) ||
 298             commit_locked_index(lock_file))
 299                 die("unable to write new index file");
 300
 301         if (!opts->force)
 302                 show_local_changes(&new->commit->object);
 303
 304         return 0;
 305 }
 306
 307 static void report_tracking(struct branch_info *new, struct checkout_opts *opts)
 308 {
 309         /*
 310          * We have switched to a new branch; is it building on
 311          * top of another branch, and if so does that other branch
 312          * have changes we do not have yet?
 313          */
 314         char *base;
 315         unsigned char sha1[20];
 316         struct commit *ours, *theirs;
 317         char symmetric[84];
 318         struct rev_info revs;
 319         const char *rev_argv[10];
 320         int rev_argc;
 321         int num_ours, num_theirs;
 322         const char *remote_msg;
 323         struct branch *branch = branch_get(new->name);
 324
 325         /*
 326          * Nothing to report unless we are marked to build on top of
 327          * somebody else.
 328          */
 329         if (!branch || !branch->merge || !branch->merge[0] || !branch->merge[0]->dst)
 330                 return;
 331
 332         /*
 333          * If what we used to build on no longer exists, there is
 334          * nothing to report.
 335          */
 336         base = branch->merge[0]->dst;
 337         if (!resolve_ref(base, sha1, 1, NULL))
 338                 return;
 339
 340         theirs = lookup_commit(sha1);
 341         ours = new->commit;
 342         if (!hashcmp(sha1, ours->object.sha1))
 343                 return; /* we are the same */
 344
 345         /* Run "rev-list --left-right ours...theirs" internally... */
 346         rev_argc = 0;
 347         rev_argv[rev_argc++] = NULL;
 348         rev_argv[rev_argc++] = "--left-right";
 349         rev_argv[rev_argc++] = symmetric;
 350         rev_argv[rev_argc++] = "--";
 351         rev_argv[rev_argc] = NULL;
 352
 353         strcpy(symmetric, sha1_to_hex(ours->object.sha1));
 354         strcpy(symmetric + 40, "...");
 355         strcpy(symmetric + 43, sha1_to_hex(theirs->object.sha1));
 356
 357         init_revisions(&revs, NULL);
 358         setup_revisions(rev_argc, rev_argv, &revs, NULL);
 359         prepare_revision_walk(&revs);
 360
 361         /* ... and count the commits on each side. */
 362         num_ours = 0;
 363         num_theirs = 0;
 364         while (1) {
 365                 struct commit *c = get_revision(&revs);
 366                 if (!c)
 367                         break;
 368                 if (c->object.flags & SYMMETRIC_LEFT)
 369                         num_ours++;
 370                 else
 371                         num_theirs++;
 372         }
 373
 374         if (!prefixcmp(base, "refs/remotes/")) {
 375                 remote_msg = " remote";
 376                 base += strlen("refs/remotes/");
 377         } else {
 378                 remote_msg = "";
 379         }
 380
 381         if (!num_theirs)
 382                 printf("Your branch is ahead of the tracked%s branch '%s' "
 383                        "by %d commit%s.\n",
 384                        remote_msg, base,
 385                        num_ours, (num_ours == 1) ? "" : "s");
 386         else if (!num_ours)
 387                 printf("Your branch is behind the tracked%s branch '%s' "
 388                        "by %d commit%s,\n"
 389                        "and can be fast-forwarded.\n",
 390                        remote_msg, base,
 391                        num_theirs, (num_theirs == 1) ? "" : "s");
 392         else
 393                 printf("Your branch and the tracked%s branch '%s' "
 394                        "have diverged,\nand respectively "
 395                        "have %d and %d different commit(s) each.\n",
 396                        remote_msg, base,
 397                        num_ours, num_theirs);
 398 }
 399
 400 static void update_refs_for_switch(struct checkout_opts *opts,
 401                                    struct branch_info *old,
 402                                    struct branch_info *new)
 403 {
 404         struct strbuf msg;
 405         const char *old_desc;
 406         if (opts->new_branch) {
 407                 create_branch(old->name, opts->new_branch, new->name, 0,
 408                               opts->new_branch_log, opts->track);
 409                 new->name = opts->new_branch;
 410                 setup_branch_path(new);
 411         }
 412
 413         strbuf_init(&msg, 0);
 414         old_desc = old->name;
 415         if (!old_desc)
 416                 old_desc = sha1_to_hex(old->commit->object.sha1);
 417         strbuf_addf(&msg, "checkout: moving from %s to %s",
 418                     old_desc, new->name);
 419
 420         if (new->path) {
 421                 create_symref("HEAD", new->path, msg.buf);
 422                 if (!opts->quiet) {
 423                         if (old->path && !strcmp(new->path, old->path))
 424                                 fprintf(stderr, "Already on \"%s\"\n",
 425                                         new->name);
 426                         else
 427                                 fprintf(stderr, "Switched to%s branch \"%s\"\n",
 428                                         opts->new_branch ? " a new" : "",
 429                                         new->name);
 430                 }
 431         } else if (strcmp(new->name, "HEAD")) {
 432                 update_ref(msg.buf, "HEAD", new->commit->object.sha1, NULL,
 433                            REF_NODEREF, DIE_ON_ERR);
 434                 if (!opts->quiet) {
 435                         if (old->path)
 436                                 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);
 437                         describe_detached_head("HEAD is now at", new->commit);
 438                 }
 439         }
 440         remove_branch_state();
 441         strbuf_release(&msg);
 442         if (!opts->quiet && (new->path || !strcmp(new->name, "HEAD")))
 443                 report_tracking(new, opts);
 444 }
 445
 446 static int switch_branches(struct checkout_opts *opts, struct branch_info *new)
 447 {
 448         int ret = 0;
 449         struct branch_info old;
 450         unsigned char rev[20];
 451         int flag;
 452         memset(&old, 0, sizeof(old));
 453         old.path = resolve_ref("HEAD", rev, 0, &flag);
 454         old.commit = lookup_commit_reference_gently(rev, 1);
 455         if (!(flag & REF_ISSYMREF))
 456                 old.path = NULL;
 457
 458         if (old.path && !prefixcmp(old.path, "refs/heads/"))
 459                 old.name = old.path + strlen("refs/heads/");
 460
 461         if (!new->name) {
 462                 new->name = "HEAD";
 463                 new->commit = old.commit;
 464                 if (!new->commit)
 465                         die("You are on a branch yet to be born");
 466                 parse_commit(new->commit);
 467         }
 468
 469         /*
 470          * If the new thing isn't a branch and isn't HEAD and we're
 471          * not starting a new branch, and we want messages, and we
 472          * weren't on a branch, and we're moving to a new commit,
 473          * describe the old commit.
 474          */
 475         if (!new->path && strcmp(new->name, "HEAD") && !opts->new_branch &&
 476             !opts->quiet && !old.path && new->commit != old.commit)
 477                 describe_detached_head("Previous HEAD position was", old.commit);
 478
 479         if (!old.commit) {
 480                 if (!opts->quiet) {
 481                         fprintf(stderr, "warning: You appear to be on a branch yet to be born.\n");
 482                         fprintf(stderr, "warning: Forcing checkout of %s.\n", new->name);
 483                 }
 484                 opts->force = 1;
 485         }
 486
 487         ret = merge_working_tree(opts, &old, new);
 488         if (ret)
 489                 return ret;
 490
 491         update_refs_for_switch(opts, &old, new);
 492
 493         return post_checkout_hook(old.commit, new->commit, 1);
 494 }
 495
 496 int cmd_checkout(int argc, const char **argv, const char *prefix)
 497 {
 498         struct checkout_opts opts;
 499         unsigned char rev[20];
 500         const char *arg;
 501         struct branch_info new;
 502         struct tree *source_tree = NULL;
 503         struct option options[] = {
 504                 OPT__QUIET(&opts.quiet),
 505                 OPT_STRING('b', NULL, &opts.new_branch, "new branch", "branch"),
 506                 OPT_BOOLEAN('l', NULL, &opts.new_branch_log, "log for new branch"),
 507                 OPT_SET_INT('t', "track",  &opts.track, "track",
 508                         BRANCH_TRACK_EXPLICIT),
 509                 OPT_BOOLEAN('f', NULL, &opts.force, "force"),
 510                 OPT_BOOLEAN('m', NULL, &opts.merge, "merge"),
 511                 OPT_END(),
 512         };
 513
 514         memset(&opts, 0, sizeof(opts));
 515         memset(&new, 0, sizeof(new));
 516
 517         git_config(git_default_config);
 518
 519         opts.track = git_branch_track;
 520
 521         argc = parse_options(argc, argv, options, checkout_usage, 0);
 522         if (argc) {
 523                 arg = argv[0];
 524                 if (get_sha1(arg, rev))
 525                         ;
 526                 else if ((new.commit = lookup_commit_reference_gently(rev, 1))) {
 527                         new.name = arg;
 528                         setup_branch_path(&new);
 529                         if (resolve_ref(new.path, rev, 1, NULL))
 530                                 new.commit = lookup_commit_reference(rev);
 531                         else
 532                                 new.path = NULL;
 533                         parse_commit(new.commit);
 534                         source_tree = new.commit->tree;
 535                         argv++;
 536                         argc--;
 537                 } else if ((source_tree = parse_tree_indirect(rev))) {
 538                         argv++;
 539                         argc--;
 540                 }
 541         }
 542
 543         if (argc && !strcmp(argv[0], "--")) {
 544                 argv++;
 545                 argc--;
 546         }
 547
 548         if (!opts.new_branch && (opts.track != git_branch_track))
 549                 die("git checkout: --track and --no-track require -b");
 550
 551         if (opts.force && opts.merge)
 552                 die("git checkout: -f and -m are incompatible");
 553
 554         if (argc) {
 555                 const char **pathspec = get_pathspec(prefix, argv);
 556
 557                 if (!pathspec)
 558                         die("invalid path specification");
 559
 560                 /* Checkout paths */
 561                 if (opts.new_branch || opts.force || opts.merge) {
 562                         if (argc == 1) {
 563                                 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]);
 564                         } else {
 565                                 die("git checkout: updating paths is incompatible with switching branches/forcing");
 566                         }
 567                 }
 568
 569                 return checkout_paths(source_tree, pathspec);
 570         }
 571
 572         if (new.name && !new.commit) {
 573                 die("Cannot switch branch to a non-commit.");
 574         }
 575
 576         return switch_branches(&opts, &new);
 577 }