builtin/pull.c

   1 /*
   2  * Builtin "git pull"
   3  *
   4  * Based on git-pull.sh by Junio C Hamano
   5  *
   6  * Fetch one or more remote refs and merge it/them into the current HEAD.
   7  */
   8 #include "cache.h"
   9 #include "config.h"
  10 #include "builtin.h"
  11 #include "parse-options.h"
  12 #include "exec-cmd.h"
  13 #include "run-command.h"
  14 #include "sha1-array.h"
  15 #include "remote.h"
  16 #include "dir.h"
  17 #include "refs.h"
  18 #include "refspec.h"
  19 #include "revision.h"
  20 #include "submodule.h"
  21 #include "submodule-config.h"
  22 #include "tempfile.h"
  23 #include "lockfile.h"
  24 #include "wt-status.h"
  25 #include "commit-reach.h"
  26
  27 enum rebase_type {
  28         REBASE_INVALID = -1,
  29         REBASE_FALSE = 0,
  30         REBASE_TRUE,
  31         REBASE_PRESERVE,
  32         REBASE_MERGES,
  33         REBASE_INTERACTIVE
  34 };
  35
  36 /**
  37  * Parses the value of --rebase. If value is a false value, returns
  38  * REBASE_FALSE. If value is a true value, returns REBASE_TRUE. If value is
  39  * "merges", returns REBASE_MERGES. If value is "preserve", returns
  40  * REBASE_PRESERVE. If value is a invalid value, dies with a fatal error if
  41  * fatal is true, otherwise returns REBASE_INVALID.
  42  */
  43 static enum rebase_type parse_config_rebase(const char *key, const char *value,
  44                 int fatal)
  45 {
  46         int v = git_parse_maybe_bool(value);
  47
  48         if (!v)
  49                 return REBASE_FALSE;
  50         else if (v > 0)
  51                 return REBASE_TRUE;
  52         else if (!strcmp(value, "preserve") || !strcmp(value, "p"))
  53                 return REBASE_PRESERVE;
  54         else if (!strcmp(value, "merges") || !strcmp(value, "m"))
  55                 return REBASE_MERGES;
  56         else if (!strcmp(value, "interactive") || !strcmp(value, "i"))
  57                 return REBASE_INTERACTIVE;
  58
  59         if (fatal)
  60                 die(_("Invalid value for %s: %s"), key, value);
  61         else
  62                 error(_("Invalid value for %s: %s"), key, value);
  63
  64         return REBASE_INVALID;
  65 }
  66
  67 /**
  68  * Callback for --rebase, which parses arg with parse_config_rebase().
  69  */
  70 static int parse_opt_rebase(const struct option *opt, const char *arg, int unset)
  71 {
  72         enum rebase_type *value = opt->value;
  73
  74         if (arg)
  75                 *value = parse_config_rebase("--rebase", arg, 0);
  76         else
  77                 *value = unset ? REBASE_FALSE : REBASE_TRUE;
  78         return *value == REBASE_INVALID ? -1 : 0;
  79 }
  80
  81 static const char * const pull_usage[] = {
  82         N_("git pull [<options>] [<repository> [<refspec>...]]"),
  83         NULL
  84 };
  85
  86 /* Shared options */
  87 static int opt_verbosity;
  88 static char *opt_progress;
  89 static int recurse_submodules = RECURSE_SUBMODULES_DEFAULT;
  90
  91 /* Options passed to git-merge or git-rebase */
  92 static enum rebase_type opt_rebase = -1;
  93 static char *opt_diffstat;
  94 static char *opt_log;
  95 static char *opt_signoff;
  96 static char *opt_squash;
  97 static char *opt_commit;
  98 static char *opt_edit;
  99 static char *opt_ff;
 100 static char *opt_verify_signatures;
 101 static int opt_autostash = -1;
 102 static int config_autostash;
 103 static struct argv_array opt_strategies = ARGV_ARRAY_INIT;
 104 static struct argv_array opt_strategy_opts = ARGV_ARRAY_INIT;
 105 static char *opt_gpg_sign;
 106 static int opt_allow_unrelated_histories;
 107
 108 /* Options passed to git-fetch */
 109 static char *opt_all;
 110 static char *opt_append;
 111 static char *opt_upload_pack;
 112 static int opt_force;
 113 static char *opt_tags;
 114 static char *opt_prune;
 115 static char *max_children;
 116 static int opt_dry_run;
 117 static char *opt_keep;
 118 static char *opt_depth;
 119 static char *opt_unshallow;
 120 static char *opt_update_shallow;
 121 static char *opt_refmap;
 122 static char *opt_ipv4;
 123 static char *opt_ipv6;
 124
 125 static struct option pull_options[] = {
 126         /* Shared options */
 127         OPT__VERBOSITY(&opt_verbosity),
 128         OPT_PASSTHRU(0, "progress", &opt_progress, NULL,
 129                 N_("force progress reporting"),
 130                 PARSE_OPT_NOARG),
 131         { OPTION_CALLBACK, 0, "recurse-submodules",
 132                    &recurse_submodules, N_("on-demand"),
 133                    N_("control for recursive fetching of submodules"),
 134                    PARSE_OPT_OPTARG, option_fetch_parse_recurse_submodules },
 135
 136         /* Options passed to git-merge or git-rebase */
 137         OPT_GROUP(N_("Options related to merging")),
 138         { OPTION_CALLBACK, 'r', "rebase", &opt_rebase,
 139           "(false|true|merges|preserve|interactive)",
 140           N_("incorporate changes by rebasing rather than merging"),
 141           PARSE_OPT_OPTARG, parse_opt_rebase },
 142         OPT_PASSTHRU('n', NULL, &opt_diffstat, NULL,
 143                 N_("do not show a diffstat at the end of the merge"),
 144                 PARSE_OPT_NOARG | PARSE_OPT_NONEG),
 145         OPT_PASSTHRU(0, "stat", &opt_diffstat, NULL,
 146                 N_("show a diffstat at the end of the merge"),
 147                 PARSE_OPT_NOARG),
 148         OPT_PASSTHRU(0, "summary", &opt_diffstat, NULL,
 149                 N_("(synonym to --stat)"),
 150                 PARSE_OPT_NOARG | PARSE_OPT_HIDDEN),
 151         OPT_PASSTHRU(0, "log", &opt_log, N_("n"),
 152                 N_("add (at most <n>) entries from shortlog to merge commit message"),
 153                 PARSE_OPT_OPTARG),
 154         OPT_PASSTHRU(0, "signoff", &opt_signoff, NULL,
 155                 N_("add Signed-off-by:"),
 156                 PARSE_OPT_OPTARG),
 157         OPT_PASSTHRU(0, "squash", &opt_squash, NULL,
 158                 N_("create a single commit instead of doing a merge"),
 159                 PARSE_OPT_NOARG),
 160         OPT_PASSTHRU(0, "commit", &opt_commit, NULL,
 161                 N_("perform a commit if the merge succeeds (default)"),
 162                 PARSE_OPT_NOARG),
 163         OPT_PASSTHRU(0, "edit", &opt_edit, NULL,
 164                 N_("edit message before committing"),
 165                 PARSE_OPT_NOARG),
 166         OPT_PASSTHRU(0, "ff", &opt_ff, NULL,
 167                 N_("allow fast-forward"),
 168                 PARSE_OPT_NOARG),
 169         OPT_PASSTHRU(0, "ff-only", &opt_ff, NULL,
 170                 N_("abort if fast-forward is not possible"),
 171                 PARSE_OPT_NOARG | PARSE_OPT_NONEG),
 172         OPT_PASSTHRU(0, "verify-signatures", &opt_verify_signatures, NULL,
 173                 N_("verify that the named commit has a valid GPG signature"),
 174                 PARSE_OPT_NOARG),
 175         OPT_BOOL(0, "autostash", &opt_autostash,
 176                 N_("automatically stash/stash pop before and after rebase")),
 177         OPT_PASSTHRU_ARGV('s', "strategy", &opt_strategies, N_("strategy"),
 178                 N_("merge strategy to use"),
 179                 0),
 180         OPT_PASSTHRU_ARGV('X', "strategy-option", &opt_strategy_opts,
 181                 N_("option=value"),
 182                 N_("option for selected merge strategy"),
 183                 0),
 184         OPT_PASSTHRU('S', "gpg-sign", &opt_gpg_sign, N_("key-id"),
 185                 N_("GPG sign commit"),
 186                 PARSE_OPT_OPTARG),
 187         OPT_SET_INT(0, "allow-unrelated-histories",
 188                     &opt_allow_unrelated_histories,
 189                     N_("allow merging unrelated histories"), 1),
 190
 191         /* Options passed to git-fetch */
 192         OPT_GROUP(N_("Options related to fetching")),
 193         OPT_PASSTHRU(0, "all", &opt_all, NULL,
 194                 N_("fetch from all remotes"),
 195                 PARSE_OPT_NOARG),
 196         OPT_PASSTHRU('a', "append", &opt_append, NULL,
 197                 N_("append to .git/FETCH_HEAD instead of overwriting"),
 198                 PARSE_OPT_NOARG),
 199         OPT_PASSTHRU(0, "upload-pack", &opt_upload_pack, N_("path"),
 200                 N_("path to upload pack on remote end"),
 201                 0),
 202         OPT__FORCE(&opt_force, N_("force overwrite of local branch"), 0),
 203         OPT_PASSTHRU('t', "tags", &opt_tags, NULL,
 204                 N_("fetch all tags and associated objects"),
 205                 PARSE_OPT_NOARG),
 206         OPT_PASSTHRU('p', "prune", &opt_prune, NULL,
 207                 N_("prune remote-tracking branches no longer on remote"),
 208                 PARSE_OPT_NOARG),
 209         OPT_PASSTHRU('j', "jobs", &max_children, N_("n"),
 210                 N_("number of submodules pulled in parallel"),
 211                 PARSE_OPT_OPTARG),
 212         OPT_BOOL(0, "dry-run", &opt_dry_run,
 213                 N_("dry run")),
 214         OPT_PASSTHRU('k', "keep", &opt_keep, NULL,
 215                 N_("keep downloaded pack"),
 216                 PARSE_OPT_NOARG),
 217         OPT_PASSTHRU(0, "depth", &opt_depth, N_("depth"),
 218                 N_("deepen history of shallow clone"),
 219                 0),
 220         OPT_PASSTHRU(0, "unshallow", &opt_unshallow, NULL,
 221                 N_("convert to a complete repository"),
 222                 PARSE_OPT_NONEG | PARSE_OPT_NOARG),
 223         OPT_PASSTHRU(0, "update-shallow", &opt_update_shallow, NULL,
 224                 N_("accept refs that update .git/shallow"),
 225                 PARSE_OPT_NOARG),
 226         OPT_PASSTHRU(0, "refmap", &opt_refmap, N_("refmap"),
 227                 N_("specify fetch refmap"),
 228                 PARSE_OPT_NONEG),
 229         OPT_PASSTHRU('4',  "ipv4", &opt_ipv4, NULL,
 230                 N_("use IPv4 addresses only"),
 231                 PARSE_OPT_NOARG),
 232         OPT_PASSTHRU('6',  "ipv6", &opt_ipv6, NULL,
 233                 N_("use IPv6 addresses only"),
 234                 PARSE_OPT_NOARG),
 235
 236         OPT_END()
 237 };
 238
 239 /**
 240  * Pushes "-q" or "-v" switches into arr to match the opt_verbosity level.
 241  */
 242 static void argv_push_verbosity(struct argv_array *arr)
 243 {
 244         int verbosity;
 245
 246         for (verbosity = opt_verbosity; verbosity > 0; verbosity--)
 247                 argv_array_push(arr, "-v");
 248
 249         for (verbosity = opt_verbosity; verbosity < 0; verbosity++)
 250                 argv_array_push(arr, "-q");
 251 }
 252
 253 /**
 254  * Pushes "-f" switches into arr to match the opt_force level.
 255  */
 256 static void argv_push_force(struct argv_array *arr)
 257 {
 258         int force = opt_force;
 259         while (force-- > 0)
 260                 argv_array_push(arr, "-f");
 261 }
 262
 263 /**
 264  * Sets the GIT_REFLOG_ACTION environment variable to the concatenation of argv
 265  */
 266 static void set_reflog_message(int argc, const char **argv)
 267 {
 268         int i;
 269         struct strbuf msg = STRBUF_INIT;
 270
 271         for (i = 0; i < argc; i++) {
 272                 if (i)
 273                         strbuf_addch(&msg, ' ');
 274                 strbuf_addstr(&msg, argv[i]);
 275         }
 276
 277         setenv("GIT_REFLOG_ACTION", msg.buf, 0);
 278
 279         strbuf_release(&msg);
 280 }
 281
 282 /**
 283  * If pull.ff is unset, returns NULL. If pull.ff is "true", returns "--ff". If
 284  * pull.ff is "false", returns "--no-ff". If pull.ff is "only", returns
 285  * "--ff-only". Otherwise, if pull.ff is set to an invalid value, die with an
 286  * error.
 287  */
 288 static const char *config_get_ff(void)
 289 {
 290         const char *value;
 291
 292         if (git_config_get_value("pull.ff", &value))
 293                 return NULL;
 294
 295         switch (git_parse_maybe_bool(value)) {
 296         case 0:
 297                 return "--no-ff";
 298         case 1:
 299                 return "--ff";
 300         }
 301
 302         if (!strcmp(value, "only"))
 303                 return "--ff-only";
 304
 305         die(_("Invalid value for pull.ff: %s"), value);
 306 }
 307
 308 /**
 309  * Returns the default configured value for --rebase. It first looks for the
 310  * value of "branch.$curr_branch.rebase", where $curr_branch is the current
 311  * branch, and if HEAD is detached or the configuration key does not exist,
 312  * looks for the value of "pull.rebase". If both configuration keys do not
 313  * exist, returns REBASE_FALSE.
 314  */
 315 static enum rebase_type config_get_rebase(void)
 316 {
 317         struct branch *curr_branch = branch_get("HEAD");
 318         const char *value;
 319
 320         if (curr_branch) {
 321                 char *key = xstrfmt("branch.%s.rebase", curr_branch->name);
 322
 323                 if (!git_config_get_value(key, &value)) {
 324                         enum rebase_type ret = parse_config_rebase(key, value, 1);
 325                         free(key);
 326                         return ret;
 327                 }
 328
 329                 free(key);
 330         }
 331
 332         if (!git_config_get_value("pull.rebase", &value))
 333                 return parse_config_rebase("pull.rebase", value, 1);
 334
 335         return REBASE_FALSE;
 336 }
 337
 338 /**
 339  * Read config variables.
 340  */
 341 static int git_pull_config(const char *var, const char *value, void *cb)
 342 {
 343         if (!strcmp(var, "rebase.autostash")) {
 344                 config_autostash = git_config_bool(var, value);
 345                 return 0;
 346         } else if (!strcmp(var, "submodule.recurse")) {
 347                 recurse_submodules = git_config_bool(var, value) ?
 348                         RECURSE_SUBMODULES_ON : RECURSE_SUBMODULES_OFF;
 349                 return 0;
 350         }
 351         return git_default_config(var, value, cb);
 352 }
 353
 354 /**
 355  * Appends merge candidates from FETCH_HEAD that are not marked not-for-merge
 356  * into merge_heads.
 357  */
 358 static void get_merge_heads(struct oid_array *merge_heads)
 359 {
 360         const char *filename = git_path_fetch_head(the_repository);
 361         FILE *fp;
 362         struct strbuf sb = STRBUF_INIT;
 363         struct object_id oid;
 364
 365         fp = xfopen(filename, "r");
 366         while (strbuf_getline_lf(&sb, fp) != EOF) {
 367                 if (get_oid_hex(sb.buf, &oid))
 368                         continue;  /* invalid line: does not start with SHA1 */
 369                 if (starts_with(sb.buf + GIT_SHA1_HEXSZ, "\tnot-for-merge\t"))
 370                         continue;  /* ref is not-for-merge */
 371                 oid_array_append(merge_heads, &oid);
 372         }
 373         fclose(fp);
 374         strbuf_release(&sb);
 375 }
 376
 377 /**
 378  * Used by die_no_merge_candidates() as a for_each_remote() callback to
 379  * retrieve the name of the remote if the repository only has one remote.
 380  */
 381 static int get_only_remote(struct remote *remote, void *cb_data)
 382 {
 383         const char **remote_name = cb_data;
 384
 385         if (*remote_name)
 386                 return -1;
 387
 388         *remote_name = remote->name;
 389         return 0;
 390 }
 391
 392 /**
 393  * Dies with the appropriate reason for why there are no merge candidates:
 394  *
 395  * 1. We fetched from a specific remote, and a refspec was given, but it ended
 396  *    up not fetching anything. This is usually because the user provided a
 397  *    wildcard refspec which had no matches on the remote end.
 398  *
 399  * 2. We fetched from a non-default remote, but didn't specify a branch to
 400  *    merge. We can't use the configured one because it applies to the default
 401  *    remote, thus the user must specify the branches to merge.
 402  *
 403  * 3. We fetched from the branch's or repo's default remote, but:
 404  *
 405  *    a. We are not on a branch, so there will never be a configured branch to
 406  *       merge with.
 407  *
 408  *    b. We are on a branch, but there is no configured branch to merge with.
 409  *
 410  * 4. We fetched from the branch's or repo's default remote, but the configured
 411  *    branch to merge didn't get fetched. (Either it doesn't exist, or wasn't
 412  *    part of the configured fetch refspec.)
 413  */
 414 static void NORETURN die_no_merge_candidates(const char *repo, const char **refspecs)
 415 {
 416         struct branch *curr_branch = branch_get("HEAD");
 417         const char *remote = curr_branch ? curr_branch->remote_name : NULL;
 418
 419         if (*refspecs) {
 420                 if (opt_rebase)
 421                         fprintf_ln(stderr, _("There is no candidate for rebasing against among the refs that you just fetched."));
 422                 else
 423                         fprintf_ln(stderr, _("There are no candidates for merging among the refs that you just fetched."));
 424                 fprintf_ln(stderr, _("Generally this means that you provided a wildcard refspec which had no\n"
 425                                         "matches on the remote end."));
 426         } else if (repo && curr_branch && (!remote || strcmp(repo, remote))) {
 427                 fprintf_ln(stderr, _("You asked to pull from the remote '%s', but did not specify\n"
 428                         "a branch. Because this is not the default configured remote\n"
 429                         "for your current branch, you must specify a branch on the command line."),
 430                         repo);
 431         } else if (!curr_branch) {
 432                 fprintf_ln(stderr, _("You are not currently on a branch."));
 433                 if (opt_rebase)
 434                         fprintf_ln(stderr, _("Please specify which branch you want to rebase against."));
 435                 else
 436                         fprintf_ln(stderr, _("Please specify which branch you want to merge with."));
 437                 fprintf_ln(stderr, _("See git-pull(1) for details."));
 438                 fprintf(stderr, "\n");
 439                 fprintf_ln(stderr, "    git pull %s %s", _("<remote>"), _("<branch>"));
 440                 fprintf(stderr, "\n");
 441         } else if (!curr_branch->merge_nr) {
 442                 const char *remote_name = NULL;
 443
 444                 if (for_each_remote(get_only_remote, &remote_name) || !remote_name)
 445                         remote_name = _("<remote>");
 446
 447                 fprintf_ln(stderr, _("There is no tracking information for the current branch."));
 448                 if (opt_rebase)
 449                         fprintf_ln(stderr, _("Please specify which branch you want to rebase against."));
 450                 else
 451                         fprintf_ln(stderr, _("Please specify which branch you want to merge with."));
 452                 fprintf_ln(stderr, _("See git-pull(1) for details."));
 453                 fprintf(stderr, "\n");
 454                 fprintf_ln(stderr, "    git pull %s %s", _("<remote>"), _("<branch>"));
 455                 fprintf(stderr, "\n");
 456                 fprintf_ln(stderr, _("If you wish to set tracking information for this branch you can do so with:"));
 457                 fprintf(stderr, "\n");
 458                 fprintf_ln(stderr, "    git branch --set-upstream-to=%s/%s %s\n",
 459                                 remote_name, _("<branch>"), curr_branch->name);
 460         } else
 461                 fprintf_ln(stderr, _("Your configuration specifies to merge with the ref '%s'\n"
 462                         "from the remote, but no such ref was fetched."),
 463                         *curr_branch->merge_name);
 464         exit(1);
 465 }
 466
 467 /**
 468  * Parses argv into [<repo> [<refspecs>...]], returning their values in `repo`
 469  * as a string and `refspecs` as a null-terminated array of strings. If `repo`
 470  * is not provided in argv, it is set to NULL.
 471  */
 472 static void parse_repo_refspecs(int argc, const char **argv, const char **repo,
 473                 const char ***refspecs)
 474 {
 475         if (argc > 0) {
 476                 *repo = *argv++;
 477                 argc--;
 478         } else
 479                 *repo = NULL;
 480         *refspecs = argv;
 481 }
 482
 483 /**
 484  * Runs git-fetch, returning its exit status. `repo` and `refspecs` are the
 485  * repository and refspecs to fetch, or NULL if they are not provided.
 486  */
 487 static int run_fetch(const char *repo, const char **refspecs)
 488 {
 489         struct argv_array args = ARGV_ARRAY_INIT;
 490         int ret;
 491
 492         argv_array_pushl(&args, "fetch", "--update-head-ok", NULL);
 493
 494         /* Shared options */
 495         argv_push_verbosity(&args);
 496         if (opt_progress)
 497                 argv_array_push(&args, opt_progress);
 498
 499         /* Options passed to git-fetch */
 500         if (opt_all)
 501                 argv_array_push(&args, opt_all);
 502         if (opt_append)
 503                 argv_array_push(&args, opt_append);
 504         if (opt_upload_pack)
 505                 argv_array_push(&args, opt_upload_pack);
 506         argv_push_force(&args);
 507         if (opt_tags)
 508                 argv_array_push(&args, opt_tags);
 509         if (opt_prune)
 510                 argv_array_push(&args, opt_prune);
 511         if (recurse_submodules != RECURSE_SUBMODULES_DEFAULT)
 512                 switch (recurse_submodules) {
 513                 case RECURSE_SUBMODULES_ON:
 514                         argv_array_push(&args, "--recurse-submodules=on");
 515                         break;
 516                 case RECURSE_SUBMODULES_OFF:
 517                         argv_array_push(&args, "--recurse-submodules=no");
 518                         break;
 519                 case RECURSE_SUBMODULES_ON_DEMAND:
 520                         argv_array_push(&args, "--recurse-submodules=on-demand");
 521                         break;
 522                 default:
 523                         BUG("submodule recursion option not understood");
 524                 }
 525         if (max_children)
 526                 argv_array_push(&args, max_children);
 527         if (opt_dry_run)
 528                 argv_array_push(&args, "--dry-run");
 529         if (opt_keep)
 530                 argv_array_push(&args, opt_keep);
 531         if (opt_depth)
 532                 argv_array_push(&args, opt_depth);
 533         if (opt_unshallow)
 534                 argv_array_push(&args, opt_unshallow);
 535         if (opt_update_shallow)
 536                 argv_array_push(&args, opt_update_shallow);
 537         if (opt_refmap)
 538                 argv_array_push(&args, opt_refmap);
 539         if (opt_ipv4)
 540                 argv_array_push(&args, opt_ipv4);
 541         if (opt_ipv6)
 542                 argv_array_push(&args, opt_ipv6);
 543
 544         if (repo) {
 545                 argv_array_push(&args, repo);
 546                 argv_array_pushv(&args, refspecs);
 547         } else if (*refspecs)
 548                 BUG("refspecs without repo?");
 549         ret = run_command_v_opt(args.argv, RUN_GIT_CMD);
 550         argv_array_clear(&args);
 551         return ret;
 552 }
 553
 554 /**
 555  * "Pulls into void" by branching off merge_head.
 556  */
 557 static int pull_into_void(const struct object_id *merge_head,
 558                 const struct object_id *curr_head)
 559 {
 560         /*
 561          * Two-way merge: we treat the index as based on an empty tree,
 562          * and try to fast-forward to HEAD. This ensures we will not lose
 563          * index/worktree changes that the user already made on the unborn
 564          * branch.
 565          */
 566         if (checkout_fast_forward(the_hash_algo->empty_tree, merge_head, 0))
 567                 return 1;
 568
 569         if (update_ref("initial pull", "HEAD", merge_head, curr_head, 0, UPDATE_REFS_DIE_ON_ERR))
 570                 return 1;
 571
 572         return 0;
 573 }
 574
 575 static int rebase_submodules(void)
 576 {
 577         struct child_process cp = CHILD_PROCESS_INIT;
 578
 579         cp.git_cmd = 1;
 580         cp.no_stdin = 1;
 581         argv_array_pushl(&cp.args, "submodule", "update",
 582                                    "--recursive", "--rebase", NULL);
 583         argv_push_verbosity(&cp.args);
 584
 585         return run_command(&cp);
 586 }
 587
 588 static int update_submodules(void)
 589 {
 590         struct child_process cp = CHILD_PROCESS_INIT;
 591
 592         cp.git_cmd = 1;
 593         cp.no_stdin = 1;
 594         argv_array_pushl(&cp.args, "submodule", "update",
 595                                    "--recursive", "--checkout", NULL);
 596         argv_push_verbosity(&cp.args);
 597
 598         return run_command(&cp);
 599 }
 600
 601 /**
 602  * Runs git-merge, returning its exit status.
 603  */
 604 static int run_merge(void)
 605 {
 606         int ret;
 607         struct argv_array args = ARGV_ARRAY_INIT;
 608
 609         argv_array_pushl(&args, "merge", NULL);
 610
 611         /* Shared options */
 612         argv_push_verbosity(&args);
 613         if (opt_progress)
 614                 argv_array_push(&args, opt_progress);
 615
 616         /* Options passed to git-merge */
 617         if (opt_diffstat)
 618                 argv_array_push(&args, opt_diffstat);
 619         if (opt_log)
 620                 argv_array_push(&args, opt_log);
 621         if (opt_signoff)
 622                 argv_array_push(&args, opt_signoff);
 623         if (opt_squash)
 624                 argv_array_push(&args, opt_squash);
 625         if (opt_commit)
 626                 argv_array_push(&args, opt_commit);
 627         if (opt_edit)
 628                 argv_array_push(&args, opt_edit);
 629         if (opt_ff)
 630                 argv_array_push(&args, opt_ff);
 631         if (opt_verify_signatures)
 632                 argv_array_push(&args, opt_verify_signatures);
 633         argv_array_pushv(&args, opt_strategies.argv);
 634         argv_array_pushv(&args, opt_strategy_opts.argv);
 635         if (opt_gpg_sign)
 636                 argv_array_push(&args, opt_gpg_sign);
 637         if (opt_allow_unrelated_histories > 0)
 638                 argv_array_push(&args, "--allow-unrelated-histories");
 639
 640         argv_array_push(&args, "FETCH_HEAD");
 641         ret = run_command_v_opt(args.argv, RUN_GIT_CMD);
 642         argv_array_clear(&args);
 643         return ret;
 644 }
 645
 646 /**
 647  * Returns remote's upstream branch for the current branch. If remote is NULL,
 648  * the current branch's configured default remote is used. Returns NULL if
 649  * `remote` does not name a valid remote, HEAD does not point to a branch,
 650  * remote is not the branch's configured remote or the branch does not have any
 651  * configured upstream branch.
 652  */
 653 static const char *get_upstream_branch(const char *remote)
 654 {
 655         struct remote *rm;
 656         struct branch *curr_branch;
 657         const char *curr_branch_remote;
 658
 659         rm = remote_get(remote);
 660         if (!rm)
 661                 return NULL;
 662
 663         curr_branch = branch_get("HEAD");
 664         if (!curr_branch)
 665                 return NULL;
 666
 667         curr_branch_remote = remote_for_branch(curr_branch, NULL);
 668         assert(curr_branch_remote);
 669
 670         if (strcmp(curr_branch_remote, rm->name))
 671                 return NULL;
 672
 673         return branch_get_upstream(curr_branch, NULL);
 674 }
 675
 676 /**
 677  * Derives the remote-tracking branch from the remote and refspec.
 678  *
 679  * FIXME: The current implementation assumes the default mapping of
 680  * refs/heads/<branch_name> to refs/remotes/<remote_name>/<branch_name>.
 681  */
 682 static const char *get_tracking_branch(const char *remote, const char *refspec)
 683 {
 684         struct refspec_item spec;
 685         const char *spec_src;
 686         const char *merge_branch;
 687
 688         refspec_item_init_or_die(&spec, refspec, REFSPEC_FETCH);
 689         spec_src = spec.src;
 690         if (!*spec_src || !strcmp(spec_src, "HEAD"))
 691                 spec_src = "HEAD";
 692         else if (skip_prefix(spec_src, "heads/", &spec_src))
 693                 ;
 694         else if (skip_prefix(spec_src, "refs/heads/", &spec_src))
 695                 ;
 696         else if (starts_with(spec_src, "refs/") ||
 697                 starts_with(spec_src, "tags/") ||
 698                 starts_with(spec_src, "remotes/"))
 699                 spec_src = "";
 700
 701         if (*spec_src) {
 702                 if (!strcmp(remote, "."))
 703                         merge_branch = mkpath("refs/heads/%s", spec_src);
 704                 else
 705                         merge_branch = mkpath("refs/remotes/%s/%s", remote, spec_src);
 706         } else
 707                 merge_branch = NULL;
 708
 709         refspec_item_clear(&spec);
 710         return merge_branch;
 711 }
 712
 713 /**
 714  * Given the repo and refspecs, sets fork_point to the point at which the
 715  * current branch forked from its remote-tracking branch. Returns 0 on success,
 716  * -1 on failure.
 717  */
 718 static int get_rebase_fork_point(struct object_id *fork_point, const char *repo,
 719                 const char *refspec)
 720 {
 721         int ret;
 722         struct branch *curr_branch;
 723         const char *remote_branch;
 724         struct child_process cp = CHILD_PROCESS_INIT;
 725         struct strbuf sb = STRBUF_INIT;
 726
 727         curr_branch = branch_get("HEAD");
 728         if (!curr_branch)
 729                 return -1;
 730
 731         if (refspec)
 732                 remote_branch = get_tracking_branch(repo, refspec);
 733         else
 734                 remote_branch = get_upstream_branch(repo);
 735
 736         if (!remote_branch)
 737                 return -1;
 738
 739         argv_array_pushl(&cp.args, "merge-base", "--fork-point",
 740                         remote_branch, curr_branch->name, NULL);
 741         cp.no_stdin = 1;
 742         cp.no_stderr = 1;
 743         cp.git_cmd = 1;
 744
 745         ret = capture_command(&cp, &sb, GIT_SHA1_HEXSZ);
 746         if (ret)
 747                 goto cleanup;
 748
 749         ret = get_oid_hex(sb.buf, fork_point);
 750         if (ret)
 751                 goto cleanup;
 752
 753 cleanup:
 754         strbuf_release(&sb);
 755         return ret ? -1 : 0;
 756 }
 757
 758 /**
 759  * Sets merge_base to the octopus merge base of curr_head, merge_head and
 760  * fork_point. Returns 0 if a merge base is found, 1 otherwise.
 761  */
 762 static int get_octopus_merge_base(struct object_id *merge_base,
 763                 const struct object_id *curr_head,
 764                 const struct object_id *merge_head,
 765                 const struct object_id *fork_point)
 766 {
 767         struct commit_list *revs = NULL, *result;
 768
 769         commit_list_insert(lookup_commit_reference(the_repository, curr_head),
 770                            &revs);
 771         commit_list_insert(lookup_commit_reference(the_repository, merge_head),
 772                            &revs);
 773         if (!is_null_oid(fork_point))
 774                 commit_list_insert(lookup_commit_reference(the_repository, fork_point),
 775                                    &revs);
 776
 777         result = get_octopus_merge_bases(revs);
 778         free_commit_list(revs);
 779         reduce_heads_replace(&result);
 780
 781         if (!result)
 782                 return 1;
 783
 784         oidcpy(merge_base, &result->item->object.oid);
 785         free_commit_list(result);
 786         return 0;
 787 }
 788
 789 /**
 790  * Given the current HEAD SHA1, the merge head returned from git-fetch and the
 791  * fork point calculated by get_rebase_fork_point(), runs git-rebase with the
 792  * appropriate arguments and returns its exit status.
 793  */
 794 static int run_rebase(const struct object_id *curr_head,
 795                 const struct object_id *merge_head,
 796                 const struct object_id *fork_point)
 797 {
 798         int ret;
 799         struct object_id oct_merge_base;
 800         struct argv_array args = ARGV_ARRAY_INIT;
 801
 802         if (!get_octopus_merge_base(&oct_merge_base, curr_head, merge_head, fork_point))
 803                 if (!is_null_oid(fork_point) && oideq(&oct_merge_base, fork_point))
 804                         fork_point = NULL;
 805
 806         argv_array_push(&args, "rebase");
 807
 808         /* Shared options */
 809         argv_push_verbosity(&args);
 810
 811         /* Options passed to git-rebase */
 812         if (opt_rebase == REBASE_MERGES)
 813                 argv_array_push(&args, "--rebase-merges");
 814         else if (opt_rebase == REBASE_PRESERVE)
 815                 argv_array_push(&args, "--preserve-merges");
 816         else if (opt_rebase == REBASE_INTERACTIVE)
 817                 argv_array_push(&args, "--interactive");
 818         if (opt_diffstat)
 819                 argv_array_push(&args, opt_diffstat);
 820         argv_array_pushv(&args, opt_strategies.argv);
 821         argv_array_pushv(&args, opt_strategy_opts.argv);
 822         if (opt_gpg_sign)
 823                 argv_array_push(&args, opt_gpg_sign);
 824         if (opt_autostash == 0)
 825                 argv_array_push(&args, "--no-autostash");
 826         else if (opt_autostash == 1)
 827                 argv_array_push(&args, "--autostash");
 828         if (opt_verify_signatures &&
 829             !strcmp(opt_verify_signatures, "--verify-signatures"))
 830                 warning(_("ignoring --verify-signatures for rebase"));
 831
 832         argv_array_push(&args, "--onto");
 833         argv_array_push(&args, oid_to_hex(merge_head));
 834
 835         if (fork_point && !is_null_oid(fork_point))
 836                 argv_array_push(&args, oid_to_hex(fork_point));
 837         else
 838                 argv_array_push(&args, oid_to_hex(merge_head));
 839
 840         ret = run_command_v_opt(args.argv, RUN_GIT_CMD);
 841         argv_array_clear(&args);
 842         return ret;
 843 }
 844
 845 int cmd_pull(int argc, const char **argv, const char *prefix)
 846 {
 847         const char *repo, **refspecs;
 848         struct oid_array merge_heads = OID_ARRAY_INIT;
 849         struct object_id orig_head, curr_head;
 850         struct object_id rebase_fork_point;
 851         int autostash;
 852
 853         if (!getenv("GIT_REFLOG_ACTION"))
 854                 set_reflog_message(argc, argv);
 855
 856         git_config(git_pull_config, NULL);
 857
 858         argc = parse_options(argc, argv, prefix, pull_options, pull_usage, 0);
 859
 860         parse_repo_refspecs(argc, argv, &repo, &refspecs);
 861
 862         if (!opt_ff)
 863                 opt_ff = xstrdup_or_null(config_get_ff());
 864
 865         if (opt_rebase < 0)
 866                 opt_rebase = config_get_rebase();
 867
 868         if (read_cache_unmerged())
 869                 die_resolve_conflict("pull");
 870
 871         if (file_exists(git_path_merge_head(the_repository)))
 872                 die_conclude_merge();
 873
 874         if (get_oid("HEAD", &orig_head))
 875                 oidclr(&orig_head);
 876
 877         if (!opt_rebase && opt_autostash != -1)
 878                 die(_("--[no-]autostash option is only valid with --rebase."));
 879
 880         autostash = config_autostash;
 881         if (opt_rebase) {
 882                 if (opt_autostash != -1)
 883                         autostash = opt_autostash;
 884
 885                 if (is_null_oid(&orig_head) && !is_cache_unborn())
 886                         die(_("Updating an unborn branch with changes added to the index."));
 887
 888                 if (!autostash)
 889                         require_clean_work_tree(N_("pull with rebase"),
 890                                 _("please commit or stash them."), 1, 0);
 891
 892                 if (get_rebase_fork_point(&rebase_fork_point, repo, *refspecs))
 893                         oidclr(&rebase_fork_point);
 894         }
 895
 896         if (run_fetch(repo, refspecs))
 897                 return 1;
 898
 899         if (opt_dry_run)
 900                 return 0;
 901
 902         if (get_oid("HEAD", &curr_head))
 903                 oidclr(&curr_head);
 904
 905         if (!is_null_oid(&orig_head) && !is_null_oid(&curr_head) &&
 906                         !oideq(&orig_head, &curr_head)) {
 907                 /*
 908                  * The fetch involved updating the current branch.
 909                  *
 910                  * The working tree and the index file are still based on
 911                  * orig_head commit, but we are merging into curr_head.
 912                  * Update the working tree to match curr_head.
 913                  */
 914
 915                 warning(_("fetch updated the current branch head.\n"
 916                         "fast-forwarding your working tree from\n"
 917                         "commit %s."), oid_to_hex(&orig_head));
 918
 919                 if (checkout_fast_forward(&orig_head, &curr_head, 0))
 920                         die(_("Cannot fast-forward your working tree.\n"
 921                                 "After making sure that you saved anything precious from\n"
 922                                 "$ git diff %s\n"
 923                                 "output, run\n"
 924                                 "$ git reset --hard\n"
 925                                 "to recover."), oid_to_hex(&orig_head));
 926         }
 927
 928         get_merge_heads(&merge_heads);
 929
 930         if (!merge_heads.nr)
 931                 die_no_merge_candidates(repo, refspecs);
 932
 933         if (is_null_oid(&orig_head)) {
 934                 if (merge_heads.nr > 1)
 935                         die(_("Cannot merge multiple branches into empty head."));
 936                 return pull_into_void(merge_heads.oid, &curr_head);
 937         }
 938         if (opt_rebase && merge_heads.nr > 1)
 939                 die(_("Cannot rebase onto multiple branches."));
 940
 941         if (opt_rebase) {
 942                 int ret = 0;
 943                 if ((recurse_submodules == RECURSE_SUBMODULES_ON ||
 944                      recurse_submodules == RECURSE_SUBMODULES_ON_DEMAND) &&
 945                     submodule_touches_in_range(&rebase_fork_point, &curr_head))
 946                         die(_("cannot rebase with locally recorded submodule modifications"));
 947                 if (!autostash) {
 948                         struct commit_list *list = NULL;
 949                         struct commit *merge_head, *head;
 950
 951                         head = lookup_commit_reference(the_repository,
 952                                                        &orig_head);
 953                         commit_list_insert(head, &list);
 954                         merge_head = lookup_commit_reference(the_repository,
 955                                                              &merge_heads.oid[0]);
 956                         if (is_descendant_of(merge_head, list)) {
 957                                 /* we can fast-forward this without invoking rebase */
 958                                 opt_ff = "--ff-only";
 959                                 ret = run_merge();
 960                         }
 961                 }
 962                 ret = run_rebase(&curr_head, merge_heads.oid, &rebase_fork_point);
 963
 964                 if (!ret && (recurse_submodules == RECURSE_SUBMODULES_ON ||
 965                              recurse_submodules == RECURSE_SUBMODULES_ON_DEMAND))
 966                         ret = rebase_submodules();
 967
 968                 return ret;
 969         } else {
 970                 int ret = run_merge();
 971                 if (!ret && (recurse_submodules == RECURSE_SUBMODULES_ON ||
 972                              recurse_submodules == RECURSE_SUBMODULES_ON_DEMAND))
 973                         ret = update_submodules();
 974                 return ret;
 975         }
 976 }