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 #define USE_THE_INDEX_COMPATIBILITY_MACROS
   9 #include "cache.h"
  10 #include "config.h"
  11 #include "builtin.h"
  12 #include "parse-options.h"
  13 #include "exec-cmd.h"
  14 #include "run-command.h"
  15 #include "oid-array.h"
  16 #include "remote.h"
  17 #include "dir.h"
  18 #include "rebase.h"
  19 #include "refs.h"
  20 #include "refspec.h"
  21 #include "revision.h"
  22 #include "submodule.h"
  23 #include "submodule-config.h"
  24 #include "tempfile.h"
  25 #include "lockfile.h"
  26 #include "wt-status.h"
  27 #include "commit-reach.h"
  28 #include "sequencer.h"
  29 #include "packfile.h"
  30
  31 /**
  32  * Parses the value of --rebase. If value is a false value, returns
  33  * REBASE_FALSE. If value is a true value, returns REBASE_TRUE. If value is
  34  * "merges", returns REBASE_MERGES. If value is a invalid value, dies with
  35  * a fatal error if fatal is true, otherwise returns REBASE_INVALID.
  36  */
  37 static enum rebase_type parse_config_rebase(const char *key, const char *value,
  38                 int fatal)
  39 {
  40         enum rebase_type v = rebase_parse_value(value);
  41         if (v != REBASE_INVALID)
  42                 return v;
  43
  44         if (fatal)
  45                 die(_("Invalid value for %s: %s"), key, value);
  46         else
  47                 error(_("Invalid value for %s: %s"), key, value);
  48
  49         return REBASE_INVALID;
  50 }
  51
  52 /**
  53  * Callback for --rebase, which parses arg with parse_config_rebase().
  54  */
  55 static int parse_opt_rebase(const struct option *opt, const char *arg, int unset)
  56 {
  57         enum rebase_type *value = opt->value;
  58
  59         if (arg)
  60                 *value = parse_config_rebase("--rebase", arg, 0);
  61         else
  62                 *value = unset ? REBASE_FALSE : REBASE_TRUE;
  63         return *value == REBASE_INVALID ? -1 : 0;
  64 }
  65
  66 static const char * const pull_usage[] = {
  67         N_("git pull [<options>] [<repository> [<refspec>...]]"),
  68         NULL
  69 };
  70
  71 /* Shared options */
  72 static int opt_verbosity;
  73 static char *opt_progress;
  74 static int recurse_submodules = RECURSE_SUBMODULES_DEFAULT;
  75
  76 /* Options passed to git-merge or git-rebase */
  77 static enum rebase_type opt_rebase = -1;
  78 static char *opt_diffstat;
  79 static char *opt_log;
  80 static char *opt_signoff;
  81 static char *opt_squash;
  82 static char *opt_commit;
  83 static char *opt_edit;
  84 static char *cleanup_arg;
  85 static char *opt_ff;
  86 static char *opt_verify_signatures;
  87 static char *opt_verify;
  88 static int opt_autostash = -1;
  89 static int config_autostash;
  90 static int check_trust_level = 1;
  91 static struct strvec opt_strategies = STRVEC_INIT;
  92 static struct strvec opt_strategy_opts = STRVEC_INIT;
  93 static char *opt_gpg_sign;
  94 static int opt_allow_unrelated_histories;
  95
  96 /* Options passed to git-fetch */
  97 static char *opt_all;
  98 static char *opt_append;
  99 static char *opt_upload_pack;
 100 static int opt_force;
 101 static char *opt_tags;
 102 static char *opt_prune;
 103 static char *max_children;
 104 static int opt_dry_run;
 105 static char *opt_keep;
 106 static char *opt_depth;
 107 static char *opt_unshallow;
 108 static char *opt_update_shallow;
 109 static char *opt_refmap;
 110 static char *opt_ipv4;
 111 static char *opt_ipv6;
 112 static int opt_show_forced_updates = -1;
 113 static char *set_upstream;
 114 static struct strvec opt_fetch = STRVEC_INIT;
 115
 116 static struct option pull_options[] = {
 117         /* Shared options */
 118         OPT__VERBOSITY(&opt_verbosity),
 119         OPT_PASSTHRU(0, "progress", &opt_progress, NULL,
 120                 N_("force progress reporting"),
 121                 PARSE_OPT_NOARG),
 122         OPT_CALLBACK_F(0, "recurse-submodules",
 123                    &recurse_submodules, N_("on-demand"),
 124                    N_("control for recursive fetching of submodules"),
 125                    PARSE_OPT_OPTARG, option_fetch_parse_recurse_submodules),
 126
 127         /* Options passed to git-merge or git-rebase */
 128         OPT_GROUP(N_("Options related to merging")),
 129         OPT_CALLBACK_F('r', "rebase", &opt_rebase,
 130                 "(false|true|merges|interactive)",
 131                 N_("incorporate changes by rebasing rather than merging"),
 132                 PARSE_OPT_OPTARG, parse_opt_rebase),
 133         OPT_PASSTHRU('n', NULL, &opt_diffstat, NULL,
 134                 N_("do not show a diffstat at the end of the merge"),
 135                 PARSE_OPT_NOARG | PARSE_OPT_NONEG),
 136         OPT_PASSTHRU(0, "stat", &opt_diffstat, NULL,
 137                 N_("show a diffstat at the end of the merge"),
 138                 PARSE_OPT_NOARG),
 139         OPT_PASSTHRU(0, "summary", &opt_diffstat, NULL,
 140                 N_("(synonym to --stat)"),
 141                 PARSE_OPT_NOARG | PARSE_OPT_HIDDEN),
 142         OPT_PASSTHRU(0, "log", &opt_log, N_("n"),
 143                 N_("add (at most <n>) entries from shortlog to merge commit message"),
 144                 PARSE_OPT_OPTARG),
 145         OPT_PASSTHRU(0, "signoff", &opt_signoff, NULL,
 146                 N_("add a Signed-off-by trailer"),
 147                 PARSE_OPT_OPTARG),
 148         OPT_PASSTHRU(0, "squash", &opt_squash, NULL,
 149                 N_("create a single commit instead of doing a merge"),
 150                 PARSE_OPT_NOARG),
 151         OPT_PASSTHRU(0, "commit", &opt_commit, NULL,
 152                 N_("perform a commit if the merge succeeds (default)"),
 153                 PARSE_OPT_NOARG),
 154         OPT_PASSTHRU(0, "edit", &opt_edit, NULL,
 155                 N_("edit message before committing"),
 156                 PARSE_OPT_NOARG),
 157         OPT_CLEANUP(&cleanup_arg),
 158         OPT_PASSTHRU(0, "ff", &opt_ff, NULL,
 159                 N_("allow fast-forward"),
 160                 PARSE_OPT_NOARG),
 161         OPT_PASSTHRU(0, "ff-only", &opt_ff, NULL,
 162                 N_("abort if fast-forward is not possible"),
 163                 PARSE_OPT_NOARG | PARSE_OPT_NONEG),
 164         OPT_PASSTHRU(0, "verify", &opt_verify, NULL,
 165                 N_("control use of pre-merge-commit and commit-msg hooks"),
 166                 PARSE_OPT_NOARG),
 167         OPT_PASSTHRU(0, "verify-signatures", &opt_verify_signatures, NULL,
 168                 N_("verify that the named commit has a valid GPG signature"),
 169                 PARSE_OPT_NOARG),
 170         OPT_BOOL(0, "autostash", &opt_autostash,
 171                 N_("automatically stash/stash pop before and after")),
 172         OPT_PASSTHRU_ARGV('s', "strategy", &opt_strategies, N_("strategy"),
 173                 N_("merge strategy to use"),
 174                 0),
 175         OPT_PASSTHRU_ARGV('X', "strategy-option", &opt_strategy_opts,
 176                 N_("option=value"),
 177                 N_("option for selected merge strategy"),
 178                 0),
 179         OPT_PASSTHRU('S', "gpg-sign", &opt_gpg_sign, N_("key-id"),
 180                 N_("GPG sign commit"),
 181                 PARSE_OPT_OPTARG),
 182         OPT_SET_INT(0, "allow-unrelated-histories",
 183                     &opt_allow_unrelated_histories,
 184                     N_("allow merging unrelated histories"), 1),
 185
 186         /* Options passed to git-fetch */
 187         OPT_GROUP(N_("Options related to fetching")),
 188         OPT_PASSTHRU(0, "all", &opt_all, NULL,
 189                 N_("fetch from all remotes"),
 190                 PARSE_OPT_NOARG),
 191         OPT_PASSTHRU('a', "append", &opt_append, NULL,
 192                 N_("append to .git/FETCH_HEAD instead of overwriting"),
 193                 PARSE_OPT_NOARG),
 194         OPT_PASSTHRU(0, "upload-pack", &opt_upload_pack, N_("path"),
 195                 N_("path to upload pack on remote end"),
 196                 0),
 197         OPT__FORCE(&opt_force, N_("force overwrite of local branch"), 0),
 198         OPT_PASSTHRU('t', "tags", &opt_tags, NULL,
 199                 N_("fetch all tags and associated objects"),
 200                 PARSE_OPT_NOARG),
 201         OPT_PASSTHRU('p', "prune", &opt_prune, NULL,
 202                 N_("prune remote-tracking branches no longer on remote"),
 203                 PARSE_OPT_NOARG),
 204         OPT_PASSTHRU('j', "jobs", &max_children, N_("n"),
 205                 N_("number of submodules pulled in parallel"),
 206                 PARSE_OPT_OPTARG),
 207         OPT_BOOL(0, "dry-run", &opt_dry_run,
 208                 N_("dry run")),
 209         OPT_PASSTHRU('k', "keep", &opt_keep, NULL,
 210                 N_("keep downloaded pack"),
 211                 PARSE_OPT_NOARG),
 212         OPT_PASSTHRU(0, "depth", &opt_depth, N_("depth"),
 213                 N_("deepen history of shallow clone"),
 214                 0),
 215         OPT_PASSTHRU_ARGV(0, "shallow-since", &opt_fetch, N_("time"),
 216                 N_("deepen history of shallow repository based on time"),
 217                 0),
 218         OPT_PASSTHRU_ARGV(0, "shallow-exclude", &opt_fetch, N_("revision"),
 219                 N_("deepen history of shallow clone, excluding rev"),
 220                 0),
 221         OPT_PASSTHRU_ARGV(0, "deepen", &opt_fetch, N_("n"),
 222                 N_("deepen history of shallow clone"),
 223                 0),
 224         OPT_PASSTHRU(0, "unshallow", &opt_unshallow, NULL,
 225                 N_("convert to a complete repository"),
 226                 PARSE_OPT_NONEG | PARSE_OPT_NOARG),
 227         OPT_PASSTHRU(0, "update-shallow", &opt_update_shallow, NULL,
 228                 N_("accept refs that update .git/shallow"),
 229                 PARSE_OPT_NOARG),
 230         OPT_PASSTHRU(0, "refmap", &opt_refmap, N_("refmap"),
 231                 N_("specify fetch refmap"),
 232                 PARSE_OPT_NONEG),
 233         OPT_PASSTHRU_ARGV('o', "server-option", &opt_fetch,
 234                 N_("server-specific"),
 235                 N_("option to transmit"),
 236                 0),
 237         OPT_PASSTHRU('4',  "ipv4", &opt_ipv4, NULL,
 238                 N_("use IPv4 addresses only"),
 239                 PARSE_OPT_NOARG),
 240         OPT_PASSTHRU('6',  "ipv6", &opt_ipv6, NULL,
 241                 N_("use IPv6 addresses only"),
 242                 PARSE_OPT_NOARG),
 243         OPT_PASSTHRU_ARGV(0, "negotiation-tip", &opt_fetch, N_("revision"),
 244                 N_("report that we have only objects reachable from this object"),
 245                 0),
 246         OPT_BOOL(0, "show-forced-updates", &opt_show_forced_updates,
 247                  N_("check for forced-updates on all updated branches")),
 248         OPT_PASSTHRU(0, "set-upstream", &set_upstream, NULL,
 249                 N_("set upstream for git pull/fetch"),
 250                 PARSE_OPT_NOARG),
 251
 252         OPT_END()
 253 };
 254
 255 /**
 256  * Pushes "-q" or "-v" switches into arr to match the opt_verbosity level.
 257  */
 258 static void argv_push_verbosity(struct strvec *arr)
 259 {
 260         int verbosity;
 261
 262         for (verbosity = opt_verbosity; verbosity > 0; verbosity--)
 263                 strvec_push(arr, "-v");
 264
 265         for (verbosity = opt_verbosity; verbosity < 0; verbosity++)
 266                 strvec_push(arr, "-q");
 267 }
 268
 269 /**
 270  * Pushes "-f" switches into arr to match the opt_force level.
 271  */
 272 static void argv_push_force(struct strvec *arr)
 273 {
 274         int force = opt_force;
 275         while (force-- > 0)
 276                 strvec_push(arr, "-f");
 277 }
 278
 279 /**
 280  * Sets the GIT_REFLOG_ACTION environment variable to the concatenation of argv
 281  */
 282 static void set_reflog_message(int argc, const char **argv)
 283 {
 284         int i;
 285         struct strbuf msg = STRBUF_INIT;
 286
 287         for (i = 0; i < argc; i++) {
 288                 if (i)
 289                         strbuf_addch(&msg, ' ');
 290                 strbuf_addstr(&msg, argv[i]);
 291         }
 292
 293         setenv("GIT_REFLOG_ACTION", msg.buf, 0);
 294
 295         strbuf_release(&msg);
 296 }
 297
 298 /**
 299  * If pull.ff is unset, returns NULL. If pull.ff is "true", returns "--ff". If
 300  * pull.ff is "false", returns "--no-ff". If pull.ff is "only", returns
 301  * "--ff-only". Otherwise, if pull.ff is set to an invalid value, die with an
 302  * error.
 303  */
 304 static const char *config_get_ff(void)
 305 {
 306         const char *value;
 307
 308         if (git_config_get_value("pull.ff", &value))
 309                 return NULL;
 310
 311         switch (git_parse_maybe_bool(value)) {
 312         case 0:
 313                 return "--no-ff";
 314         case 1:
 315                 return "--ff";
 316         }
 317
 318         if (!strcmp(value, "only"))
 319                 return "--ff-only";
 320
 321         die(_("Invalid value for pull.ff: %s"), value);
 322 }
 323
 324 /**
 325  * Returns the default configured value for --rebase. It first looks for the
 326  * value of "branch.$curr_branch.rebase", where $curr_branch is the current
 327  * branch, and if HEAD is detached or the configuration key does not exist,
 328  * looks for the value of "pull.rebase". If both configuration keys do not
 329  * exist, returns REBASE_FALSE.
 330  */
 331 static enum rebase_type config_get_rebase(int *rebase_unspecified)
 332 {
 333         struct branch *curr_branch = branch_get("HEAD");
 334         const char *value;
 335
 336         if (curr_branch) {
 337                 char *key = xstrfmt("branch.%s.rebase", curr_branch->name);
 338
 339                 if (!git_config_get_value(key, &value)) {
 340                         enum rebase_type ret = parse_config_rebase(key, value, 1);
 341                         free(key);
 342                         return ret;
 343                 }
 344
 345                 free(key);
 346         }
 347
 348         if (!git_config_get_value("pull.rebase", &value))
 349                 return parse_config_rebase("pull.rebase", value, 1);
 350
 351         *rebase_unspecified = 1;
 352
 353         return REBASE_FALSE;
 354 }
 355
 356 /**
 357  * Read config variables.
 358  */
 359 static int git_pull_config(const char *var, const char *value, void *cb)
 360 {
 361         int status;
 362
 363         if (!strcmp(var, "rebase.autostash")) {
 364                 config_autostash = git_config_bool(var, value);
 365                 return 0;
 366         } else if (!strcmp(var, "submodule.recurse")) {
 367                 recurse_submodules = git_config_bool(var, value) ?
 368                         RECURSE_SUBMODULES_ON : RECURSE_SUBMODULES_OFF;
 369                 return 0;
 370         } else if (!strcmp(var, "gpg.mintrustlevel")) {
 371                 check_trust_level = 0;
 372         }
 373
 374         status = git_gpg_config(var, value, cb);
 375         if (status)
 376                 return status;
 377
 378         return git_default_config(var, value, cb);
 379 }
 380
 381 /**
 382  * Appends merge candidates from FETCH_HEAD that are not marked not-for-merge
 383  * into merge_heads.
 384  */
 385 static void get_merge_heads(struct oid_array *merge_heads)
 386 {
 387         const char *filename = git_path_fetch_head(the_repository);
 388         FILE *fp;
 389         struct strbuf sb = STRBUF_INIT;
 390         struct object_id oid;
 391
 392         fp = xfopen(filename, "r");
 393         while (strbuf_getline_lf(&sb, fp) != EOF) {
 394                 const char *p;
 395                 if (parse_oid_hex(sb.buf, &oid, &p))
 396                         continue;  /* invalid line: does not start with object ID */
 397                 if (starts_with(p, "\tnot-for-merge\t"))
 398                         continue;  /* ref is not-for-merge */
 399                 oid_array_append(merge_heads, &oid);
 400         }
 401         fclose(fp);
 402         strbuf_release(&sb);
 403 }
 404
 405 /**
 406  * Used by die_no_merge_candidates() as a for_each_remote() callback to
 407  * retrieve the name of the remote if the repository only has one remote.
 408  */
 409 static int get_only_remote(struct remote *remote, void *cb_data)
 410 {
 411         const char **remote_name = cb_data;
 412
 413         if (*remote_name)
 414                 return -1;
 415
 416         *remote_name = remote->name;
 417         return 0;
 418 }
 419
 420 /**
 421  * Dies with the appropriate reason for why there are no merge candidates:
 422  *
 423  * 1. We fetched from a specific remote, and a refspec was given, but it ended
 424  *    up not fetching anything. This is usually because the user provided a
 425  *    wildcard refspec which had no matches on the remote end.
 426  *
 427  * 2. We fetched from a non-default remote, but didn't specify a branch to
 428  *    merge. We can't use the configured one because it applies to the default
 429  *    remote, thus the user must specify the branches to merge.
 430  *
 431  * 3. We fetched from the branch's or repo's default remote, but:
 432  *
 433  *    a. We are not on a branch, so there will never be a configured branch to
 434  *       merge with.
 435  *
 436  *    b. We are on a branch, but there is no configured branch to merge with.
 437  *
 438  * 4. We fetched from the branch's or repo's default remote, but the configured
 439  *    branch to merge didn't get fetched. (Either it doesn't exist, or wasn't
 440  *    part of the configured fetch refspec.)
 441  */
 442 static void NORETURN die_no_merge_candidates(const char *repo, const char **refspecs)
 443 {
 444         struct branch *curr_branch = branch_get("HEAD");
 445         const char *remote = curr_branch ? curr_branch->remote_name : NULL;
 446
 447         if (*refspecs) {
 448                 if (opt_rebase)
 449                         fprintf_ln(stderr, _("There is no candidate for rebasing against among the refs that you just fetched."));
 450                 else
 451                         fprintf_ln(stderr, _("There are no candidates for merging among the refs that you just fetched."));
 452                 fprintf_ln(stderr, _("Generally this means that you provided a wildcard refspec which had no\n"
 453                                         "matches on the remote end."));
 454         } else if (repo && curr_branch && (!remote || strcmp(repo, remote))) {
 455                 fprintf_ln(stderr, _("You asked to pull from the remote '%s', but did not specify\n"
 456                         "a branch. Because this is not the default configured remote\n"
 457                         "for your current branch, you must specify a branch on the command line."),
 458                         repo);
 459         } else if (!curr_branch) {
 460                 fprintf_ln(stderr, _("You are not currently on a branch."));
 461                 if (opt_rebase)
 462                         fprintf_ln(stderr, _("Please specify which branch you want to rebase against."));
 463                 else
 464                         fprintf_ln(stderr, _("Please specify which branch you want to merge with."));
 465                 fprintf_ln(stderr, _("See git-pull(1) for details."));
 466                 fprintf(stderr, "\n");
 467                 fprintf_ln(stderr, "    git pull %s %s", _("<remote>"), _("<branch>"));
 468                 fprintf(stderr, "\n");
 469         } else if (!curr_branch->merge_nr) {
 470                 const char *remote_name = NULL;
 471
 472                 if (for_each_remote(get_only_remote, &remote_name) || !remote_name)
 473                         remote_name = _("<remote>");
 474
 475                 fprintf_ln(stderr, _("There is no tracking information for the current branch."));
 476                 if (opt_rebase)
 477                         fprintf_ln(stderr, _("Please specify which branch you want to rebase against."));
 478                 else
 479                         fprintf_ln(stderr, _("Please specify which branch you want to merge with."));
 480                 fprintf_ln(stderr, _("See git-pull(1) for details."));
 481                 fprintf(stderr, "\n");
 482                 fprintf_ln(stderr, "    git pull %s %s", _("<remote>"), _("<branch>"));
 483                 fprintf(stderr, "\n");
 484                 fprintf_ln(stderr, _("If you wish to set tracking information for this branch you can do so with:"));
 485                 fprintf(stderr, "\n");
 486                 fprintf_ln(stderr, "    git branch --set-upstream-to=%s/%s %s\n",
 487                                 remote_name, _("<branch>"), curr_branch->name);
 488         } else
 489                 fprintf_ln(stderr, _("Your configuration specifies to merge with the ref '%s'\n"
 490                         "from the remote, but no such ref was fetched."),
 491                         *curr_branch->merge_name);
 492         exit(1);
 493 }
 494
 495 /**
 496  * Parses argv into [<repo> [<refspecs>...]], returning their values in `repo`
 497  * as a string and `refspecs` as a null-terminated array of strings. If `repo`
 498  * is not provided in argv, it is set to NULL.
 499  */
 500 static void parse_repo_refspecs(int argc, const char **argv, const char **repo,
 501                 const char ***refspecs)
 502 {
 503         if (argc > 0) {
 504                 *repo = *argv++;
 505                 argc--;
 506         } else
 507                 *repo = NULL;
 508         *refspecs = argv;
 509 }
 510
 511 /**
 512  * Runs git-fetch, returning its exit status. `repo` and `refspecs` are the
 513  * repository and refspecs to fetch, or NULL if they are not provided.
 514  */
 515 static int run_fetch(const char *repo, const char **refspecs)
 516 {
 517         struct strvec args = STRVEC_INIT;
 518         int ret;
 519
 520         strvec_pushl(&args, "fetch", "--update-head-ok", NULL);
 521
 522         /* Shared options */
 523         argv_push_verbosity(&args);
 524         if (opt_progress)
 525                 strvec_push(&args, opt_progress);
 526
 527         /* Options passed to git-fetch */
 528         if (opt_all)
 529                 strvec_push(&args, opt_all);
 530         if (opt_append)
 531                 strvec_push(&args, opt_append);
 532         if (opt_upload_pack)
 533                 strvec_push(&args, opt_upload_pack);
 534         argv_push_force(&args);
 535         if (opt_tags)
 536                 strvec_push(&args, opt_tags);
 537         if (opt_prune)
 538                 strvec_push(&args, opt_prune);
 539         if (recurse_submodules != RECURSE_SUBMODULES_DEFAULT)
 540                 switch (recurse_submodules) {
 541                 case RECURSE_SUBMODULES_ON:
 542                         strvec_push(&args, "--recurse-submodules=on");
 543                         break;
 544                 case RECURSE_SUBMODULES_OFF:
 545                         strvec_push(&args, "--recurse-submodules=no");
 546                         break;
 547                 case RECURSE_SUBMODULES_ON_DEMAND:
 548                         strvec_push(&args, "--recurse-submodules=on-demand");
 549                         break;
 550                 default:
 551                         BUG("submodule recursion option not understood");
 552                 }
 553         if (max_children)
 554                 strvec_push(&args, max_children);
 555         if (opt_dry_run)
 556                 strvec_push(&args, "--dry-run");
 557         if (opt_keep)
 558                 strvec_push(&args, opt_keep);
 559         if (opt_depth)
 560                 strvec_push(&args, opt_depth);
 561         if (opt_unshallow)
 562                 strvec_push(&args, opt_unshallow);
 563         if (opt_update_shallow)
 564                 strvec_push(&args, opt_update_shallow);
 565         if (opt_refmap)
 566                 strvec_push(&args, opt_refmap);
 567         if (opt_ipv4)
 568                 strvec_push(&args, opt_ipv4);
 569         if (opt_ipv6)
 570                 strvec_push(&args, opt_ipv6);
 571         if (opt_show_forced_updates > 0)
 572                 strvec_push(&args, "--show-forced-updates");
 573         else if (opt_show_forced_updates == 0)
 574                 strvec_push(&args, "--no-show-forced-updates");
 575         if (set_upstream)
 576                 strvec_push(&args, set_upstream);
 577         strvec_pushv(&args, opt_fetch.v);
 578
 579         if (repo) {
 580                 strvec_push(&args, repo);
 581                 strvec_pushv(&args, refspecs);
 582         } else if (*refspecs)
 583                 BUG("refspecs without repo?");
 584         ret = run_command_v_opt(args.v, RUN_GIT_CMD | RUN_CLOSE_OBJECT_STORE);
 585         strvec_clear(&args);
 586         return ret;
 587 }
 588
 589 /**
 590  * "Pulls into void" by branching off merge_head.
 591  */
 592 static int pull_into_void(const struct object_id *merge_head,
 593                 const struct object_id *curr_head)
 594 {
 595         if (opt_verify_signatures) {
 596                 struct commit *commit;
 597
 598                 commit = lookup_commit(the_repository, merge_head);
 599                 if (!commit)
 600                         die(_("unable to access commit %s"),
 601                             oid_to_hex(merge_head));
 602
 603                 verify_merge_signature(commit, opt_verbosity,
 604                                        check_trust_level);
 605         }
 606
 607         /*
 608          * Two-way merge: we treat the index as based on an empty tree,
 609          * and try to fast-forward to HEAD. This ensures we will not lose
 610          * index/worktree changes that the user already made on the unborn
 611          * branch.
 612          */
 613         if (checkout_fast_forward(the_repository,
 614                                   the_hash_algo->empty_tree,
 615                                   merge_head, 0))
 616                 return 1;
 617
 618         if (update_ref("initial pull", "HEAD", merge_head, curr_head, 0, UPDATE_REFS_DIE_ON_ERR))
 619                 return 1;
 620
 621         return 0;
 622 }
 623
 624 static int rebase_submodules(void)
 625 {
 626         struct child_process cp = CHILD_PROCESS_INIT;
 627
 628         cp.git_cmd = 1;
 629         cp.no_stdin = 1;
 630         strvec_pushl(&cp.args, "submodule", "update",
 631                      "--recursive", "--rebase", NULL);
 632         argv_push_verbosity(&cp.args);
 633
 634         return run_command(&cp);
 635 }
 636
 637 static int update_submodules(void)
 638 {
 639         struct child_process cp = CHILD_PROCESS_INIT;
 640
 641         cp.git_cmd = 1;
 642         cp.no_stdin = 1;
 643         strvec_pushl(&cp.args, "submodule", "update",
 644                      "--recursive", "--checkout", NULL);
 645         argv_push_verbosity(&cp.args);
 646
 647         return run_command(&cp);
 648 }
 649
 650 /**
 651  * Runs git-merge, returning its exit status.
 652  */
 653 static int run_merge(void)
 654 {
 655         int ret;
 656         struct strvec args = STRVEC_INIT;
 657
 658         strvec_pushl(&args, "merge", NULL);
 659
 660         /* Shared options */
 661         argv_push_verbosity(&args);
 662         if (opt_progress)
 663                 strvec_push(&args, opt_progress);
 664
 665         /* Options passed to git-merge */
 666         if (opt_diffstat)
 667                 strvec_push(&args, opt_diffstat);
 668         if (opt_log)
 669                 strvec_push(&args, opt_log);
 670         if (opt_signoff)
 671                 strvec_push(&args, opt_signoff);
 672         if (opt_squash)
 673                 strvec_push(&args, opt_squash);
 674         if (opt_commit)
 675                 strvec_push(&args, opt_commit);
 676         if (opt_edit)
 677                 strvec_push(&args, opt_edit);
 678         if (cleanup_arg)
 679                 strvec_pushf(&args, "--cleanup=%s", cleanup_arg);
 680         if (opt_ff)
 681                 strvec_push(&args, opt_ff);
 682         if (opt_verify)
 683                 strvec_push(&args, opt_verify);
 684         if (opt_verify_signatures)
 685                 strvec_push(&args, opt_verify_signatures);
 686         strvec_pushv(&args, opt_strategies.v);
 687         strvec_pushv(&args, opt_strategy_opts.v);
 688         if (opt_gpg_sign)
 689                 strvec_push(&args, opt_gpg_sign);
 690         if (opt_autostash == 0)
 691                 strvec_push(&args, "--no-autostash");
 692         else if (opt_autostash == 1)
 693                 strvec_push(&args, "--autostash");
 694         if (opt_allow_unrelated_histories > 0)
 695                 strvec_push(&args, "--allow-unrelated-histories");
 696
 697         strvec_push(&args, "FETCH_HEAD");
 698         ret = run_command_v_opt(args.v, RUN_GIT_CMD);
 699         strvec_clear(&args);
 700         return ret;
 701 }
 702
 703 /**
 704  * Returns remote's upstream branch for the current branch. If remote is NULL,
 705  * the current branch's configured default remote is used. Returns NULL if
 706  * `remote` does not name a valid remote, HEAD does not point to a branch,
 707  * remote is not the branch's configured remote or the branch does not have any
 708  * configured upstream branch.
 709  */
 710 static const char *get_upstream_branch(const char *remote)
 711 {
 712         struct remote *rm;
 713         struct branch *curr_branch;
 714         const char *curr_branch_remote;
 715
 716         rm = remote_get(remote);
 717         if (!rm)
 718                 return NULL;
 719
 720         curr_branch = branch_get("HEAD");
 721         if (!curr_branch)
 722                 return NULL;
 723
 724         curr_branch_remote = remote_for_branch(curr_branch, NULL);
 725         assert(curr_branch_remote);
 726
 727         if (strcmp(curr_branch_remote, rm->name))
 728                 return NULL;
 729
 730         return branch_get_upstream(curr_branch, NULL);
 731 }
 732
 733 /**
 734  * Derives the remote-tracking branch from the remote and refspec.
 735  *
 736  * FIXME: The current implementation assumes the default mapping of
 737  * refs/heads/<branch_name> to refs/remotes/<remote_name>/<branch_name>.
 738  */
 739 static const char *get_tracking_branch(const char *remote, const char *refspec)
 740 {
 741         struct refspec_item spec;
 742         const char *spec_src;
 743         const char *merge_branch;
 744
 745         refspec_item_init_or_die(&spec, refspec, REFSPEC_FETCH);
 746         spec_src = spec.src;
 747         if (!*spec_src || !strcmp(spec_src, "HEAD"))
 748                 spec_src = "HEAD";
 749         else if (skip_prefix(spec_src, "heads/", &spec_src))
 750                 ;
 751         else if (skip_prefix(spec_src, "refs/heads/", &spec_src))
 752                 ;
 753         else if (starts_with(spec_src, "refs/") ||
 754                 starts_with(spec_src, "tags/") ||
 755                 starts_with(spec_src, "remotes/"))
 756                 spec_src = "";
 757
 758         if (*spec_src) {
 759                 if (!strcmp(remote, "."))
 760                         merge_branch = mkpath("refs/heads/%s", spec_src);
 761                 else
 762                         merge_branch = mkpath("refs/remotes/%s/%s", remote, spec_src);
 763         } else
 764                 merge_branch = NULL;
 765
 766         refspec_item_clear(&spec);
 767         return merge_branch;
 768 }
 769
 770 /**
 771  * Given the repo and refspecs, sets fork_point to the point at which the
 772  * current branch forked from its remote-tracking branch. Returns 0 on success,
 773  * -1 on failure.
 774  */
 775 static int get_rebase_fork_point(struct object_id *fork_point, const char *repo,
 776                 const char *refspec)
 777 {
 778         int ret;
 779         struct branch *curr_branch;
 780         const char *remote_branch;
 781         struct child_process cp = CHILD_PROCESS_INIT;
 782         struct strbuf sb = STRBUF_INIT;
 783
 784         curr_branch = branch_get("HEAD");
 785         if (!curr_branch)
 786                 return -1;
 787
 788         if (refspec)
 789                 remote_branch = get_tracking_branch(repo, refspec);
 790         else
 791                 remote_branch = get_upstream_branch(repo);
 792
 793         if (!remote_branch)
 794                 return -1;
 795
 796         strvec_pushl(&cp.args, "merge-base", "--fork-point",
 797                      remote_branch, curr_branch->name, NULL);
 798         cp.no_stdin = 1;
 799         cp.no_stderr = 1;
 800         cp.git_cmd = 1;
 801
 802         ret = capture_command(&cp, &sb, GIT_MAX_HEXSZ);
 803         if (ret)
 804                 goto cleanup;
 805
 806         ret = get_oid_hex(sb.buf, fork_point);
 807         if (ret)
 808                 goto cleanup;
 809
 810 cleanup:
 811         strbuf_release(&sb);
 812         return ret ? -1 : 0;
 813 }
 814
 815 /**
 816  * Sets merge_base to the octopus merge base of curr_head, merge_head and
 817  * fork_point. Returns 0 if a merge base is found, 1 otherwise.
 818  */
 819 static int get_octopus_merge_base(struct object_id *merge_base,
 820                 const struct object_id *curr_head,
 821                 const struct object_id *merge_head,
 822                 const struct object_id *fork_point)
 823 {
 824         struct commit_list *revs = NULL, *result;
 825
 826         commit_list_insert(lookup_commit_reference(the_repository, curr_head),
 827                            &revs);
 828         commit_list_insert(lookup_commit_reference(the_repository, merge_head),
 829                            &revs);
 830         if (!is_null_oid(fork_point))
 831                 commit_list_insert(lookup_commit_reference(the_repository, fork_point),
 832                                    &revs);
 833
 834         result = get_octopus_merge_bases(revs);
 835         free_commit_list(revs);
 836         reduce_heads_replace(&result);
 837
 838         if (!result)
 839                 return 1;
 840
 841         oidcpy(merge_base, &result->item->object.oid);
 842         free_commit_list(result);
 843         return 0;
 844 }
 845
 846 /**
 847  * Given the current HEAD oid, the merge head returned from git-fetch and the
 848  * fork point calculated by get_rebase_fork_point(), compute the <newbase> and
 849  * <upstream> arguments to use for the upcoming git-rebase invocation.
 850  */
 851 static int get_rebase_newbase_and_upstream(struct object_id *newbase,
 852                 struct object_id *upstream,
 853                 const struct object_id *curr_head,
 854                 const struct object_id *merge_head,
 855                 const struct object_id *fork_point)
 856 {
 857         struct object_id oct_merge_base;
 858
 859         if (!get_octopus_merge_base(&oct_merge_base, curr_head, merge_head, fork_point))
 860                 if (!is_null_oid(fork_point) && oideq(&oct_merge_base, fork_point))
 861                         fork_point = NULL;
 862
 863         if (fork_point && !is_null_oid(fork_point))
 864                 oidcpy(upstream, fork_point);
 865         else
 866                 oidcpy(upstream, merge_head);
 867
 868         oidcpy(newbase, merge_head);
 869
 870         return 0;
 871 }
 872
 873 /**
 874  * Given the <newbase> and <upstream> calculated by
 875  * get_rebase_newbase_and_upstream(), runs git-rebase with the
 876  * appropriate arguments and returns its exit status.
 877  */
 878 static int run_rebase(const struct object_id *newbase,
 879                 const struct object_id *upstream)
 880 {
 881         int ret;
 882         struct strvec args = STRVEC_INIT;
 883
 884         strvec_push(&args, "rebase");
 885
 886         /* Shared options */
 887         argv_push_verbosity(&args);
 888
 889         /* Options passed to git-rebase */
 890         if (opt_rebase == REBASE_MERGES)
 891                 strvec_push(&args, "--rebase-merges");
 892         else if (opt_rebase == REBASE_INTERACTIVE)
 893                 strvec_push(&args, "--interactive");
 894         if (opt_diffstat)
 895                 strvec_push(&args, opt_diffstat);
 896         strvec_pushv(&args, opt_strategies.v);
 897         strvec_pushv(&args, opt_strategy_opts.v);
 898         if (opt_gpg_sign)
 899                 strvec_push(&args, opt_gpg_sign);
 900         if (opt_signoff)
 901                 strvec_push(&args, opt_signoff);
 902         if (opt_autostash == 0)
 903                 strvec_push(&args, "--no-autostash");
 904         else if (opt_autostash == 1)
 905                 strvec_push(&args, "--autostash");
 906         if (opt_verify_signatures &&
 907             !strcmp(opt_verify_signatures, "--verify-signatures"))
 908                 warning(_("ignoring --verify-signatures for rebase"));
 909
 910         strvec_push(&args, "--onto");
 911         strvec_push(&args, oid_to_hex(newbase));
 912
 913         strvec_push(&args, oid_to_hex(upstream));
 914
 915         ret = run_command_v_opt(args.v, RUN_GIT_CMD);
 916         strvec_clear(&args);
 917         return ret;
 918 }
 919
 920 static int get_can_ff(struct object_id *orig_head,
 921                       struct oid_array *merge_heads)
 922 {
 923         int ret;
 924         struct commit_list *list = NULL;
 925         struct commit *merge_head, *head;
 926         struct object_id *orig_merge_head;
 927
 928         if (merge_heads->nr > 1)
 929                 return 0;
 930
 931         orig_merge_head = &merge_heads->oid[0];
 932         head = lookup_commit_reference(the_repository, orig_head);
 933         commit_list_insert(head, &list);
 934         merge_head = lookup_commit_reference(the_repository, orig_merge_head);
 935         ret = repo_is_descendant_of(the_repository, merge_head, list);
 936         free_commit_list(list);
 937         return ret;
 938 }
 939
 940 /*
 941  * Is orig_head a descendant of _all_ merge_heads?
 942  * Unfortunately is_descendant_of() cannot be used as it asks
 943  * if orig_head is a descendant of at least one of them.
 944  */
 945 static int already_up_to_date(struct object_id *orig_head,
 946                               struct oid_array *merge_heads)
 947 {
 948         int i;
 949         struct commit *ours;
 950
 951         ours = lookup_commit_reference(the_repository, orig_head);
 952         for (i = 0; i < merge_heads->nr; i++) {
 953                 struct commit_list *list = NULL;
 954                 struct commit *theirs;
 955                 int ok;
 956
 957                 theirs = lookup_commit_reference(the_repository, &merge_heads->oid[i]);
 958                 commit_list_insert(theirs, &list);
 959                 ok = repo_is_descendant_of(the_repository, ours, list);
 960                 free_commit_list(list);
 961                 if (!ok)
 962                         return 0;
 963         }
 964         return 1;
 965 }
 966
 967 static void show_advice_pull_non_ff(void)
 968 {
 969         advise(_("You have divergent branches and need to specify how to reconcile them.\n"
 970                  "You can do so by running one of the following commands sometime before\n"
 971                  "your next pull:\n"
 972                  "\n"
 973                  "  git config pull.rebase false  # merge (the default strategy)\n"
 974                  "  git config pull.rebase true   # rebase\n"
 975                  "  git config pull.ff only       # fast-forward only\n"
 976                  "\n"
 977                  "You can replace \"git config\" with \"git config --global\" to set a default\n"
 978                  "preference for all repositories. You can also pass --rebase, --no-rebase,\n"
 979                  "or --ff-only on the command line to override the configured default per\n"
 980                  "invocation.\n"));
 981 }
 982
 983 int cmd_pull(int argc, const char **argv, const char *prefix)
 984 {
 985         const char *repo, **refspecs;
 986         struct oid_array merge_heads = OID_ARRAY_INIT;
 987         struct object_id orig_head, curr_head;
 988         struct object_id rebase_fork_point;
 989         int rebase_unspecified = 0;
 990         int can_ff;
 991         int divergent;
 992
 993         if (!getenv("GIT_REFLOG_ACTION"))
 994                 set_reflog_message(argc, argv);
 995
 996         git_config(git_pull_config, NULL);
 997
 998         argc = parse_options(argc, argv, prefix, pull_options, pull_usage, 0);
 999
1000         if (cleanup_arg)
1001                 /*
1002                  * this only checks the validity of cleanup_arg; we don't need
1003                  * a valid value for use_editor
1004                  */
1005                 get_cleanup_mode(cleanup_arg, 0);
1006
1007         parse_repo_refspecs(argc, argv, &repo, &refspecs);
1008
1009         if (!opt_ff) {
1010                 opt_ff = xstrdup_or_null(config_get_ff());
1011                 /*
1012                  * A subtle point: opt_ff was set on the line above via
1013                  * reading from config.  opt_rebase, in contrast, is set
1014                  * before this point via command line options.  The setting
1015                  * of opt_rebase via reading from config (using
1016                  * config_get_rebase()) does not happen until later.  We
1017                  * are relying on the next if-condition happening before
1018                  * the config_get_rebase() call so that an explicit
1019                  * "--rebase" can override a config setting of
1020                  * pull.ff=only.
1021                  */
1022                 if (opt_rebase >= 0 && opt_ff && !strcmp(opt_ff, "--ff-only"))
1023                         opt_ff = "--ff";
1024         }
1025
1026         if (opt_rebase < 0)
1027                 opt_rebase = config_get_rebase(&rebase_unspecified);
1028
1029         if (read_cache_unmerged())
1030                 die_resolve_conflict("pull");
1031
1032         if (file_exists(git_path_merge_head(the_repository)))
1033                 die_conclude_merge();
1034
1035         if (get_oid("HEAD", &orig_head))
1036                 oidclr(&orig_head);
1037
1038         if (opt_rebase) {
1039                 int autostash = config_autostash;
1040                 if (opt_autostash != -1)
1041                         autostash = opt_autostash;
1042
1043                 if (is_null_oid(&orig_head) && !is_cache_unborn())
1044                         die(_("Updating an unborn branch with changes added to the index."));
1045
1046                 if (!autostash)
1047                         require_clean_work_tree(the_repository,
1048                                 N_("pull with rebase"),
1049                                 _("please commit or stash them."), 1, 0);
1050
1051                 if (get_rebase_fork_point(&rebase_fork_point, repo, *refspecs))
1052                         oidclr(&rebase_fork_point);
1053         }
1054
1055         if (run_fetch(repo, refspecs))
1056                 return 1;
1057
1058         if (opt_dry_run)
1059                 return 0;
1060
1061         if (get_oid("HEAD", &curr_head))
1062                 oidclr(&curr_head);
1063
1064         if (!is_null_oid(&orig_head) && !is_null_oid(&curr_head) &&
1065                         !oideq(&orig_head, &curr_head)) {
1066                 /*
1067                  * The fetch involved updating the current branch.
1068                  *
1069                  * The working tree and the index file are still based on
1070                  * orig_head commit, but we are merging into curr_head.
1071                  * Update the working tree to match curr_head.
1072                  */
1073
1074                 warning(_("fetch updated the current branch head.\n"
1075                         "fast-forwarding your working tree from\n"
1076                         "commit %s."), oid_to_hex(&orig_head));
1077
1078                 if (checkout_fast_forward(the_repository, &orig_head,
1079                                           &curr_head, 0))
1080                         die(_("Cannot fast-forward your working tree.\n"
1081                                 "After making sure that you saved anything precious from\n"
1082                                 "$ git diff %s\n"
1083                                 "output, run\n"
1084                                 "$ git reset --hard\n"
1085                                 "to recover."), oid_to_hex(&orig_head));
1086         }
1087
1088         get_merge_heads(&merge_heads);
1089
1090         if (!merge_heads.nr)
1091                 die_no_merge_candidates(repo, refspecs);
1092
1093         if (is_null_oid(&orig_head)) {
1094                 if (merge_heads.nr > 1)
1095                         die(_("Cannot merge multiple branches into empty head."));
1096                 return pull_into_void(merge_heads.oid, &curr_head);
1097         }
1098         if (merge_heads.nr > 1) {
1099                 if (opt_rebase)
1100                         die(_("Cannot rebase onto multiple branches."));
1101                 if (opt_ff && !strcmp(opt_ff, "--ff-only"))
1102                         die(_("Cannot fast-forward to multiple branches."));
1103         }
1104
1105         can_ff = get_can_ff(&orig_head, &merge_heads);
1106         divergent = !can_ff && !already_up_to_date(&orig_head, &merge_heads);
1107
1108         /* ff-only takes precedence over rebase */
1109         if (opt_ff && !strcmp(opt_ff, "--ff-only")) {
1110                 if (divergent)
1111                         die_ff_impossible();
1112                 opt_rebase = REBASE_FALSE;
1113         }
1114         /* If no action specified and we can't fast forward, then warn. */
1115         if (!opt_ff && rebase_unspecified && divergent) {
1116                 show_advice_pull_non_ff();
1117                 die(_("Need to specify how to reconcile divergent branches."));
1118         }
1119
1120         if (opt_rebase) {
1121                 int ret = 0;
1122
1123                 struct object_id newbase;
1124                 struct object_id upstream;
1125                 get_rebase_newbase_and_upstream(&newbase, &upstream, &curr_head,
1126                                                 merge_heads.oid, &rebase_fork_point);
1127
1128                 if ((recurse_submodules == RECURSE_SUBMODULES_ON ||
1129                      recurse_submodules == RECURSE_SUBMODULES_ON_DEMAND) &&
1130                     submodule_touches_in_range(the_repository, &upstream, &curr_head))
1131                         die(_("cannot rebase with locally recorded submodule modifications"));
1132
1133                 if (can_ff) {
1134                         /* we can fast-forward this without invoking rebase */
1135                         opt_ff = "--ff-only";
1136                         ret = run_merge();
1137                 } else {
1138                         ret = run_rebase(&newbase, &upstream);
1139                 }
1140
1141                 if (!ret && (recurse_submodules == RECURSE_SUBMODULES_ON ||
1142                              recurse_submodules == RECURSE_SUBMODULES_ON_DEMAND))
1143                         ret = rebase_submodules();
1144
1145                 return ret;
1146         } else {
1147                 int ret = run_merge();
1148                 if (!ret && (recurse_submodules == RECURSE_SUBMODULES_ON ||
1149                              recurse_submodules == RECURSE_SUBMODULES_ON_DEMAND))
1150                         ret = update_submodules();
1151                 return ret;
1152         }
1153 }