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
   9 #define USE_THE_REPOSITORY_VARIABLE
  10 #include "builtin.h"
  11 #include "advice.h"
  12 #include "config.h"
  13 #include "gettext.h"
  14 #include "hex.h"
  15 #include "merge.h"
  16 #include "object-name.h"
  17 #include "parse-options.h"
  18 #include "run-command.h"
  19 #include "oid-array.h"
  20 #include "remote.h"
  21 #include "dir.h"
  22 #include "path.h"
  23 #include "read-cache-ll.h"
  24 #include "rebase.h"
  25 #include "refs.h"
  26 #include "refspec.h"
  27 #include "submodule.h"
  28 #include "submodule-config.h"
  29 #include "wt-status.h"
  30 #include "commit-reach.h"
  31 #include "sequencer.h"
  32
  33 /**
  34  * Parses the value of --rebase. If value is a false value, returns
  35  * REBASE_FALSE. If value is a true value, returns REBASE_TRUE. If value is
  36  * "merges", returns REBASE_MERGES. If value is a invalid value, dies with
  37  * a fatal error if fatal is true, otherwise returns REBASE_INVALID.
  38  */
  39 static enum rebase_type parse_config_rebase(const char *key, const char *value,
  40                 int fatal)
  41 {
  42         enum rebase_type v = rebase_parse_value(value);
  43         if (v != REBASE_INVALID)
  44                 return v;
  45
  46         if (fatal)
  47                 die(_("invalid value for '%s': '%s'"), key, value);
  48         else
  49                 error(_("invalid value for '%s': '%s'"), key, value);
  50
  51         return REBASE_INVALID;
  52 }
  53
  54 /**
  55  * Callback for --rebase, which parses arg with parse_config_rebase().
  56  */
  57 static int parse_opt_rebase(const struct option *opt, const char *arg, int unset)
  58 {
  59         enum rebase_type *value = opt->value;
  60
  61         if (arg)
  62                 *value = parse_config_rebase("--rebase", arg, 0);
  63         else
  64                 *value = unset ? REBASE_FALSE : REBASE_TRUE;
  65         return *value == REBASE_INVALID ? -1 : 0;
  66 }
  67
  68 static const char * const pull_usage[] = {
  69         N_("git pull [<options>] [<repository> [<refspec>...]]"),
  70         NULL
  71 };
  72
  73 /* Shared options */
  74 static int opt_verbosity;
  75 static const char *opt_progress;
  76 static int recurse_submodules = RECURSE_SUBMODULES_DEFAULT;
  77 static int recurse_submodules_cli = RECURSE_SUBMODULES_DEFAULT;
  78
  79 /* Options passed to git-merge or git-rebase */
  80 static enum rebase_type opt_rebase = -1;
  81 static const char *opt_diffstat;
  82 static const char *opt_log;
  83 static const char *opt_signoff;
  84 static const char *opt_squash;
  85 static const char *opt_commit;
  86 static const char *opt_edit;
  87 static const char *cleanup_arg;
  88 static char *opt_ff;
  89 static const char *opt_verify_signatures;
  90 static const char *opt_verify;
  91 static int opt_autostash = -1;
  92 static int config_autostash;
  93 static int check_trust_level = 1;
  94 static struct strvec opt_strategies = STRVEC_INIT;
  95 static struct strvec opt_strategy_opts = STRVEC_INIT;
  96 static const char *opt_gpg_sign;
  97 static int opt_allow_unrelated_histories;
  98
  99 /* Options passed to git-fetch */
 100 static const char *opt_all;
 101 static const char *opt_append;
 102 static const char *opt_upload_pack;
 103 static int opt_force;
 104 static const char *opt_tags;
 105 static const char *opt_prune;
 106 static const char *max_children;
 107 static int opt_dry_run;
 108 static const char *opt_keep;
 109 static const char *opt_depth;
 110 static const char *opt_unshallow;
 111 static const char *opt_update_shallow;
 112 static const char *opt_refmap;
 113 static const char *opt_ipv4;
 114 static const char *opt_ipv6;
 115 static int opt_show_forced_updates = -1;
 116 static const char *set_upstream;
 117 static struct strvec opt_fetch = STRVEC_INIT;
 118
 119 static struct option pull_options[] = {
 120         /* Shared options */
 121         OPT__VERBOSITY(&opt_verbosity),
 122         OPT_PASSTHRU(0, "progress", &opt_progress, NULL,
 123                 N_("force progress reporting"),
 124                 PARSE_OPT_NOARG),
 125         OPT_CALLBACK_F(0, "recurse-submodules",
 126                    &recurse_submodules_cli, N_("on-demand"),
 127                    N_("control for recursive fetching of submodules"),
 128                    PARSE_OPT_OPTARG, option_fetch_parse_recurse_submodules),
 129
 130         /* Options passed to git-merge or git-rebase */
 131         OPT_GROUP(N_("Options related to merging")),
 132         OPT_CALLBACK_F('r', "rebase", &opt_rebase,
 133                 "(false|true|merges|interactive)",
 134                 N_("incorporate changes by rebasing rather than merging"),
 135                 PARSE_OPT_OPTARG, parse_opt_rebase),
 136         OPT_PASSTHRU('n', NULL, &opt_diffstat, NULL,
 137                 N_("do not show a diffstat at the end of the merge"),
 138                 PARSE_OPT_NOARG | PARSE_OPT_NONEG),
 139         OPT_PASSTHRU(0, "stat", &opt_diffstat, NULL,
 140                 N_("show a diffstat at the end of the merge"),
 141                 PARSE_OPT_NOARG),
 142         OPT_PASSTHRU(0, "summary", &opt_diffstat, NULL,
 143                 N_("(synonym to --stat)"),
 144                 PARSE_OPT_NOARG | PARSE_OPT_HIDDEN),
 145         OPT_PASSTHRU(0, "log", &opt_log, N_("n"),
 146                 N_("add (at most <n>) entries from shortlog to merge commit message"),
 147                 PARSE_OPT_OPTARG),
 148         OPT_PASSTHRU(0, "signoff", &opt_signoff, NULL,
 149                 N_("add a Signed-off-by trailer"),
 150                 PARSE_OPT_OPTARG),
 151         OPT_PASSTHRU(0, "squash", &opt_squash, NULL,
 152                 N_("create a single commit instead of doing a merge"),
 153                 PARSE_OPT_NOARG),
 154         OPT_PASSTHRU(0, "commit", &opt_commit, NULL,
 155                 N_("perform a commit if the merge succeeds (default)"),
 156                 PARSE_OPT_NOARG),
 157         OPT_PASSTHRU(0, "edit", &opt_edit, NULL,
 158                 N_("edit message before committing"),
 159                 PARSE_OPT_NOARG),
 160         OPT_CLEANUP(&cleanup_arg),
 161         OPT_PASSTHRU(0, "ff", &opt_ff, NULL,
 162                 N_("allow fast-forward"),
 163                 PARSE_OPT_NOARG),
 164         OPT_PASSTHRU(0, "ff-only", &opt_ff, NULL,
 165                 N_("abort if fast-forward is not possible"),
 166                 PARSE_OPT_NOARG | PARSE_OPT_NONEG),
 167         OPT_PASSTHRU(0, "verify", &opt_verify, NULL,
 168                 N_("control use of pre-merge-commit and commit-msg hooks"),
 169                 PARSE_OPT_NOARG),
 170         OPT_PASSTHRU(0, "verify-signatures", &opt_verify_signatures, NULL,
 171                 N_("verify that the named commit has a valid GPG signature"),
 172                 PARSE_OPT_NOARG),
 173         OPT_BOOL(0, "autostash", &opt_autostash,
 174                 N_("automatically stash/stash pop before and after")),
 175         OPT_PASSTHRU_ARGV('s', "strategy", &opt_strategies, N_("strategy"),
 176                 N_("merge strategy to use"),
 177                 0),
 178         OPT_PASSTHRU_ARGV('X', "strategy-option", &opt_strategy_opts,
 179                 N_("option=value"),
 180                 N_("option for selected merge strategy"),
 181                 0),
 182         OPT_PASSTHRU('S', "gpg-sign", &opt_gpg_sign, N_("key-id"),
 183                 N_("GPG sign commit"),
 184                 PARSE_OPT_OPTARG),
 185         OPT_SET_INT(0, "allow-unrelated-histories",
 186                     &opt_allow_unrelated_histories,
 187                     N_("allow merging unrelated histories"), 1),
 188
 189         /* Options passed to git-fetch */
 190         OPT_GROUP(N_("Options related to fetching")),
 191         OPT_PASSTHRU(0, "all", &opt_all, NULL,
 192                 N_("fetch from all remotes"),
 193                 PARSE_OPT_NOARG),
 194         OPT_PASSTHRU('a', "append", &opt_append, NULL,
 195                 N_("append to .git/FETCH_HEAD instead of overwriting"),
 196                 PARSE_OPT_NOARG),
 197         OPT_PASSTHRU(0, "upload-pack", &opt_upload_pack, N_("path"),
 198                 N_("path to upload pack on remote end"),
 199                 0),
 200         OPT__FORCE(&opt_force, N_("force overwrite of local branch"), 0),
 201         OPT_PASSTHRU('t', "tags", &opt_tags, NULL,
 202                 N_("fetch all tags and associated objects"),
 203                 PARSE_OPT_NOARG),
 204         OPT_PASSTHRU('p', "prune", &opt_prune, NULL,
 205                 N_("prune remote-tracking branches no longer on remote"),
 206                 PARSE_OPT_NOARG),
 207         OPT_PASSTHRU('j', "jobs", &max_children, N_("n"),
 208                 N_("number of submodules pulled in parallel"),
 209                 PARSE_OPT_OPTARG),
 210         OPT_BOOL(0, "dry-run", &opt_dry_run,
 211                 N_("dry run")),
 212         OPT_PASSTHRU('k', "keep", &opt_keep, NULL,
 213                 N_("keep downloaded pack"),
 214                 PARSE_OPT_NOARG),
 215         OPT_PASSTHRU(0, "depth", &opt_depth, N_("depth"),
 216                 N_("deepen history of shallow clone"),
 217                 0),
 218         OPT_PASSTHRU_ARGV(0, "shallow-since", &opt_fetch, N_("time"),
 219                 N_("deepen history of shallow repository based on time"),
 220                 0),
 221         OPT_PASSTHRU_ARGV(0, "shallow-exclude", &opt_fetch, N_("revision"),
 222                 N_("deepen history of shallow clone, excluding rev"),
 223                 0),
 224         OPT_PASSTHRU_ARGV(0, "deepen", &opt_fetch, N_("n"),
 225                 N_("deepen history of shallow clone"),
 226                 0),
 227         OPT_PASSTHRU(0, "unshallow", &opt_unshallow, NULL,
 228                 N_("convert to a complete repository"),
 229                 PARSE_OPT_NONEG | PARSE_OPT_NOARG),
 230         OPT_PASSTHRU(0, "update-shallow", &opt_update_shallow, NULL,
 231                 N_("accept refs that update .git/shallow"),
 232                 PARSE_OPT_NOARG),
 233         OPT_PASSTHRU(0, "refmap", &opt_refmap, N_("refmap"),
 234                 N_("specify fetch refmap"),
 235                 PARSE_OPT_NONEG),
 236         OPT_PASSTHRU_ARGV('o', "server-option", &opt_fetch,
 237                 N_("server-specific"),
 238                 N_("option to transmit"),
 239                 0),
 240         OPT_PASSTHRU('4',  "ipv4", &opt_ipv4, NULL,
 241                 N_("use IPv4 addresses only"),
 242                 PARSE_OPT_NOARG),
 243         OPT_PASSTHRU('6',  "ipv6", &opt_ipv6, NULL,
 244                 N_("use IPv6 addresses only"),
 245                 PARSE_OPT_NOARG),
 246         OPT_PASSTHRU_ARGV(0, "negotiation-tip", &opt_fetch, N_("revision"),
 247                 N_("report that we have only objects reachable from this object"),
 248                 0),
 249         OPT_BOOL(0, "show-forced-updates", &opt_show_forced_updates,
 250                  N_("check for forced-updates on all updated branches")),
 251         OPT_PASSTHRU(0, "set-upstream", &set_upstream, NULL,
 252                 N_("set upstream for git pull/fetch"),
 253                 PARSE_OPT_NOARG),
 254
 255         OPT_END()
 256 };
 257
 258 /**
 259  * Pushes "-q" or "-v" switches into arr to match the opt_verbosity level.
 260  */
 261 static void argv_push_verbosity(struct strvec *arr)
 262 {
 263         int verbosity;
 264
 265         for (verbosity = opt_verbosity; verbosity > 0; verbosity--)
 266                 strvec_push(arr, "-v");
 267
 268         for (verbosity = opt_verbosity; verbosity < 0; verbosity++)
 269                 strvec_push(arr, "-q");
 270 }
 271
 272 /**
 273  * Pushes "-f" switches into arr to match the opt_force level.
 274  */
 275 static void argv_push_force(struct strvec *arr)
 276 {
 277         int force = opt_force;
 278         while (force-- > 0)
 279                 strvec_push(arr, "-f");
 280 }
 281
 282 /**
 283  * Sets the GIT_REFLOG_ACTION environment variable to the concatenation of argv
 284  */
 285 static void set_reflog_message(int argc, const char **argv)
 286 {
 287         int i;
 288         struct strbuf msg = STRBUF_INIT;
 289
 290         for (i = 0; i < argc; i++) {
 291                 if (i)
 292                         strbuf_addch(&msg, ' ');
 293                 strbuf_addstr(&msg, argv[i]);
 294         }
 295
 296         setenv("GIT_REFLOG_ACTION", msg.buf, 0);
 297
 298         strbuf_release(&msg);
 299 }
 300
 301 /**
 302  * If pull.ff is unset, returns NULL. If pull.ff is "true", returns "--ff". If
 303  * pull.ff is "false", returns "--no-ff". If pull.ff is "only", returns
 304  * "--ff-only". Otherwise, if pull.ff is set to an invalid value, die with an
 305  * error.
 306  */
 307 static const char *config_get_ff(void)
 308 {
 309         const char *value;
 310
 311         if (git_config_get_value("pull.ff", &value))
 312                 return NULL;
 313
 314         switch (git_parse_maybe_bool(value)) {
 315         case 0:
 316                 return "--no-ff";
 317         case 1:
 318                 return "--ff";
 319         }
 320
 321         if (!strcmp(value, "only"))
 322                 return "--ff-only";
 323
 324         die(_("invalid value for '%s': '%s'"), "pull.ff", value);
 325 }
 326
 327 /**
 328  * Returns the default configured value for --rebase. It first looks for the
 329  * value of "branch.$curr_branch.rebase", where $curr_branch is the current
 330  * branch, and if HEAD is detached or the configuration key does not exist,
 331  * looks for the value of "pull.rebase". If both configuration keys do not
 332  * exist, returns REBASE_FALSE.
 333  */
 334 static enum rebase_type config_get_rebase(int *rebase_unspecified)
 335 {
 336         struct branch *curr_branch = branch_get("HEAD");
 337         const char *value;
 338
 339         if (curr_branch) {
 340                 char *key = xstrfmt("branch.%s.rebase", curr_branch->name);
 341
 342                 if (!git_config_get_value(key, &value)) {
 343                         enum rebase_type ret = parse_config_rebase(key, value, 1);
 344                         free(key);
 345                         return ret;
 346                 }
 347
 348                 free(key);
 349         }
 350
 351         if (!git_config_get_value("pull.rebase", &value))
 352                 return parse_config_rebase("pull.rebase", value, 1);
 353
 354         *rebase_unspecified = 1;
 355
 356         return REBASE_FALSE;
 357 }
 358
 359 /**
 360  * Read config variables.
 361  */
 362 static int git_pull_config(const char *var, const char *value,
 363                            const struct config_context *ctx, void *cb)
 364 {
 365         if (!strcmp(var, "rebase.autostash")) {
 366                 config_autostash = git_config_bool(var, value);
 367                 return 0;
 368         } else if (!strcmp(var, "submodule.recurse")) {
 369                 recurse_submodules = git_config_bool(var, value) ?
 370                         RECURSE_SUBMODULES_ON : RECURSE_SUBMODULES_OFF;
 371                 return 0;
 372         } else if (!strcmp(var, "gpg.mintrustlevel")) {
 373                 check_trust_level = 0;
 374         }
 375
 376         return git_default_config(var, value, ctx, cb);
 377 }
 378
 379 /**
 380  * Appends merge candidates from FETCH_HEAD that are not marked not-for-merge
 381  * into merge_heads.
 382  */
 383 static void get_merge_heads(struct oid_array *merge_heads)
 384 {
 385         const char *filename = git_path_fetch_head(the_repository);
 386         FILE *fp;
 387         struct strbuf sb = STRBUF_INIT;
 388         struct object_id oid;
 389
 390         fp = xfopen(filename, "r");
 391         while (strbuf_getline_lf(&sb, fp) != EOF) {
 392                 const char *p;
 393                 if (parse_oid_hex(sb.buf, &oid, &p))
 394                         continue;  /* invalid line: does not start with object ID */
 395                 if (starts_with(p, "\tnot-for-merge\t"))
 396                         continue;  /* ref is not-for-merge */
 397                 oid_array_append(merge_heads, &oid);
 398         }
 399         fclose(fp);
 400         strbuf_release(&sb);
 401 }
 402
 403 /**
 404  * Used by die_no_merge_candidates() as a for_each_remote() callback to
 405  * retrieve the name of the remote if the repository only has one remote.
 406  */
 407 static int get_only_remote(struct remote *remote, void *cb_data)
 408 {
 409         const char **remote_name = cb_data;
 410
 411         if (*remote_name)
 412                 return -1;
 413
 414         *remote_name = remote->name;
 415         return 0;
 416 }
 417
 418 /**
 419  * Dies with the appropriate reason for why there are no merge candidates:
 420  *
 421  * 1. We fetched from a specific remote, and a refspec was given, but it ended
 422  *    up not fetching anything. This is usually because the user provided a
 423  *    wildcard refspec which had no matches on the remote end.
 424  *
 425  * 2. We fetched from a non-default remote, but didn't specify a branch to
 426  *    merge. We can't use the configured one because it applies to the default
 427  *    remote, thus the user must specify the branches to merge.
 428  *
 429  * 3. We fetched from the branch's or repo's default remote, but:
 430  *
 431  *    a. We are not on a branch, so there will never be a configured branch to
 432  *       merge with.
 433  *
 434  *    b. We are on a branch, but there is no configured branch to merge with.
 435  *
 436  * 4. We fetched from the branch's or repo's default remote, but the configured
 437  *    branch to merge didn't get fetched. (Either it doesn't exist, or wasn't
 438  *    part of the configured fetch refspec.)
 439  */
 440 static void NORETURN die_no_merge_candidates(const char *repo, const char **refspecs)
 441 {
 442         struct branch *curr_branch = branch_get("HEAD");
 443         const char *remote = curr_branch ? curr_branch->remote_name : NULL;
 444
 445         if (*refspecs) {
 446                 if (opt_rebase)
 447                         fprintf_ln(stderr, _("There is no candidate for rebasing against among the refs that you just fetched."));
 448                 else
 449                         fprintf_ln(stderr, _("There are no candidates for merging among the refs that you just fetched."));
 450                 fprintf_ln(stderr, _("Generally this means that you provided a wildcard refspec which had no\n"
 451                                         "matches on the remote end."));
 452         } else if (repo && curr_branch && (!remote || strcmp(repo, remote))) {
 453                 fprintf_ln(stderr, _("You asked to pull from the remote '%s', but did not specify\n"
 454                         "a branch. Because this is not the default configured remote\n"
 455                         "for your current branch, you must specify a branch on the command line."),
 456                         repo);
 457         } else if (!curr_branch) {
 458                 fprintf_ln(stderr, _("You are not currently on a branch."));
 459                 if (opt_rebase)
 460                         fprintf_ln(stderr, _("Please specify which branch you want to rebase against."));
 461                 else
 462                         fprintf_ln(stderr, _("Please specify which branch you want to merge with."));
 463                 fprintf_ln(stderr, _("See git-pull(1) for details."));
 464                 fprintf(stderr, "\n");
 465                 fprintf_ln(stderr, "    git pull %s %s", _("<remote>"), _("<branch>"));
 466                 fprintf(stderr, "\n");
 467         } else if (!curr_branch->merge_nr) {
 468                 const char *remote_name = NULL;
 469
 470                 if (for_each_remote(get_only_remote, &remote_name) || !remote_name)
 471                         remote_name = _("<remote>");
 472
 473                 fprintf_ln(stderr, _("There is no tracking information for the current branch."));
 474                 if (opt_rebase)
 475                         fprintf_ln(stderr, _("Please specify which branch you want to rebase against."));
 476                 else
 477                         fprintf_ln(stderr, _("Please specify which branch you want to merge with."));
 478                 fprintf_ln(stderr, _("See git-pull(1) for details."));
 479                 fprintf(stderr, "\n");
 480                 fprintf_ln(stderr, "    git pull %s %s", _("<remote>"), _("<branch>"));
 481                 fprintf(stderr, "\n");
 482                 fprintf_ln(stderr, _("If you wish to set tracking information for this branch you can do so with:"));
 483                 fprintf(stderr, "\n");
 484                 fprintf_ln(stderr, "    git branch --set-upstream-to=%s/%s %s\n",
 485                                 remote_name, _("<branch>"), curr_branch->name);
 486         } else
 487                 fprintf_ln(stderr, _("Your configuration specifies to merge with the ref '%s'\n"
 488                         "from the remote, but no such ref was fetched."),
 489                         *curr_branch->merge_name);
 490         exit(1);
 491 }
 492
 493 /**
 494  * Parses argv into [<repo> [<refspecs>...]], returning their values in `repo`
 495  * as a string and `refspecs` as a null-terminated array of strings. If `repo`
 496  * is not provided in argv, it is set to NULL.
 497  */
 498 static void parse_repo_refspecs(int argc, const char **argv, const char **repo,
 499                 const char ***refspecs)
 500 {
 501         if (argc > 0) {
 502                 *repo = *argv++;
 503                 argc--;
 504         } else
 505                 *repo = NULL;
 506         *refspecs = argv;
 507 }
 508
 509 /**
 510  * Runs git-fetch, returning its exit status. `repo` and `refspecs` are the
 511  * repository and refspecs to fetch, or NULL if they are not provided.
 512  */
 513 static int run_fetch(const char *repo, const char **refspecs)
 514 {
 515         struct child_process cmd = CHILD_PROCESS_INIT;
 516
 517         strvec_pushl(&cmd.args, "fetch", "--update-head-ok", NULL);
 518
 519         /* Shared options */
 520         argv_push_verbosity(&cmd.args);
 521         if (opt_progress)
 522                 strvec_push(&cmd.args, opt_progress);
 523
 524         /* Options passed to git-fetch */
 525         if (opt_all)
 526                 strvec_push(&cmd.args, opt_all);
 527         if (opt_append)
 528                 strvec_push(&cmd.args, opt_append);
 529         if (opt_upload_pack)
 530                 strvec_push(&cmd.args, opt_upload_pack);
 531         argv_push_force(&cmd.args);
 532         if (opt_tags)
 533                 strvec_push(&cmd.args, opt_tags);
 534         if (opt_prune)
 535                 strvec_push(&cmd.args, opt_prune);
 536         if (recurse_submodules_cli != RECURSE_SUBMODULES_DEFAULT)
 537                 switch (recurse_submodules_cli) {
 538                 case RECURSE_SUBMODULES_ON:
 539                         strvec_push(&cmd.args, "--recurse-submodules=on");
 540                         break;
 541                 case RECURSE_SUBMODULES_OFF:
 542                         strvec_push(&cmd.args, "--recurse-submodules=no");
 543                         break;
 544                 case RECURSE_SUBMODULES_ON_DEMAND:
 545                         strvec_push(&cmd.args, "--recurse-submodules=on-demand");
 546                         break;
 547                 default:
 548                         BUG("submodule recursion option not understood");
 549                 }
 550         if (max_children)
 551                 strvec_push(&cmd.args, max_children);
 552         if (opt_dry_run)
 553                 strvec_push(&cmd.args, "--dry-run");
 554         if (opt_keep)
 555                 strvec_push(&cmd.args, opt_keep);
 556         if (opt_depth)
 557                 strvec_push(&cmd.args, opt_depth);
 558         if (opt_unshallow)
 559                 strvec_push(&cmd.args, opt_unshallow);
 560         if (opt_update_shallow)
 561                 strvec_push(&cmd.args, opt_update_shallow);
 562         if (opt_refmap)
 563                 strvec_push(&cmd.args, opt_refmap);
 564         if (opt_ipv4)
 565                 strvec_push(&cmd.args, opt_ipv4);
 566         if (opt_ipv6)
 567                 strvec_push(&cmd.args, opt_ipv6);
 568         if (opt_show_forced_updates > 0)
 569                 strvec_push(&cmd.args, "--show-forced-updates");
 570         else if (opt_show_forced_updates == 0)
 571                 strvec_push(&cmd.args, "--no-show-forced-updates");
 572         if (set_upstream)
 573                 strvec_push(&cmd.args, set_upstream);
 574         strvec_pushv(&cmd.args, opt_fetch.v);
 575
 576         if (repo) {
 577                 strvec_push(&cmd.args, repo);
 578                 strvec_pushv(&cmd.args, refspecs);
 579         } else if (*refspecs)
 580                 BUG("refspecs without repo?");
 581         cmd.git_cmd = 1;
 582         cmd.close_object_store = 1;
 583         return run_command(&cmd);
 584 }
 585
 586 /**
 587  * "Pulls into void" by branching off merge_head.
 588  */
 589 static int pull_into_void(const struct object_id *merge_head,
 590                 const struct object_id *curr_head)
 591 {
 592         if (opt_verify_signatures) {
 593                 struct commit *commit;
 594
 595                 commit = lookup_commit(the_repository, merge_head);
 596                 if (!commit)
 597                         die(_("unable to access commit %s"),
 598                             oid_to_hex(merge_head));
 599
 600                 verify_merge_signature(commit, opt_verbosity,
 601                                        check_trust_level);
 602         }
 603
 604         /*
 605          * Two-way merge: we treat the index as based on an empty tree,
 606          * and try to fast-forward to HEAD. This ensures we will not lose
 607          * index/worktree changes that the user already made on the unborn
 608          * branch.
 609          */
 610         if (checkout_fast_forward(the_repository,
 611                                   the_hash_algo->empty_tree,
 612                                   merge_head, 0))
 613                 return 1;
 614
 615         if (refs_update_ref(get_main_ref_store(the_repository), "initial pull", "HEAD", merge_head, curr_head, 0, UPDATE_REFS_DIE_ON_ERR))
 616                 return 1;
 617
 618         return 0;
 619 }
 620
 621 static int rebase_submodules(void)
 622 {
 623         struct child_process cp = CHILD_PROCESS_INIT;
 624
 625         cp.git_cmd = 1;
 626         cp.no_stdin = 1;
 627         strvec_pushl(&cp.args, "submodule", "update",
 628                      "--recursive", "--rebase", NULL);
 629         argv_push_verbosity(&cp.args);
 630
 631         return run_command(&cp);
 632 }
 633
 634 static int update_submodules(void)
 635 {
 636         struct child_process cp = CHILD_PROCESS_INIT;
 637
 638         cp.git_cmd = 1;
 639         cp.no_stdin = 1;
 640         strvec_pushl(&cp.args, "submodule", "update",
 641                      "--recursive", "--checkout", NULL);
 642         argv_push_verbosity(&cp.args);
 643
 644         return run_command(&cp);
 645 }
 646
 647 /**
 648  * Runs git-merge, returning its exit status.
 649  */
 650 static int run_merge(void)
 651 {
 652         struct child_process cmd = CHILD_PROCESS_INIT;
 653
 654         strvec_pushl(&cmd.args, "merge", NULL);
 655
 656         /* Shared options */
 657         argv_push_verbosity(&cmd.args);
 658         if (opt_progress)
 659                 strvec_push(&cmd.args, opt_progress);
 660
 661         /* Options passed to git-merge */
 662         if (opt_diffstat)
 663                 strvec_push(&cmd.args, opt_diffstat);
 664         if (opt_log)
 665                 strvec_push(&cmd.args, opt_log);
 666         if (opt_signoff)
 667                 strvec_push(&cmd.args, opt_signoff);
 668         if (opt_squash)
 669                 strvec_push(&cmd.args, opt_squash);
 670         if (opt_commit)
 671                 strvec_push(&cmd.args, opt_commit);
 672         if (opt_edit)
 673                 strvec_push(&cmd.args, opt_edit);
 674         if (cleanup_arg)
 675                 strvec_pushf(&cmd.args, "--cleanup=%s", cleanup_arg);
 676         if (opt_ff)
 677                 strvec_push(&cmd.args, opt_ff);
 678         if (opt_verify)
 679                 strvec_push(&cmd.args, opt_verify);
 680         if (opt_verify_signatures)
 681                 strvec_push(&cmd.args, opt_verify_signatures);
 682         strvec_pushv(&cmd.args, opt_strategies.v);
 683         strvec_pushv(&cmd.args, opt_strategy_opts.v);
 684         if (opt_gpg_sign)
 685                 strvec_push(&cmd.args, opt_gpg_sign);
 686         if (opt_autostash == 0)
 687                 strvec_push(&cmd.args, "--no-autostash");
 688         else if (opt_autostash == 1)
 689                 strvec_push(&cmd.args, "--autostash");
 690         if (opt_allow_unrelated_histories > 0)
 691                 strvec_push(&cmd.args, "--allow-unrelated-histories");
 692
 693         strvec_push(&cmd.args, "FETCH_HEAD");
 694         cmd.git_cmd = 1;
 695         return run_command(&cmd);
 696 }
 697
 698 /**
 699  * Returns remote's upstream branch for the current branch. If remote is NULL,
 700  * the current branch's configured default remote is used. Returns NULL if
 701  * `remote` does not name a valid remote, HEAD does not point to a branch,
 702  * remote is not the branch's configured remote or the branch does not have any
 703  * configured upstream branch.
 704  */
 705 static const char *get_upstream_branch(const char *remote)
 706 {
 707         struct remote *rm;
 708         struct branch *curr_branch;
 709         const char *curr_branch_remote;
 710
 711         rm = remote_get(remote);
 712         if (!rm)
 713                 return NULL;
 714
 715         curr_branch = branch_get("HEAD");
 716         if (!curr_branch)
 717                 return NULL;
 718
 719         curr_branch_remote = remote_for_branch(curr_branch, NULL);
 720         assert(curr_branch_remote);
 721
 722         if (strcmp(curr_branch_remote, rm->name))
 723                 return NULL;
 724
 725         return branch_get_upstream(curr_branch, NULL);
 726 }
 727
 728 /**
 729  * Derives the remote-tracking branch from the remote and refspec.
 730  *
 731  * FIXME: The current implementation assumes the default mapping of
 732  * refs/heads/<branch_name> to refs/remotes/<remote_name>/<branch_name>.
 733  */
 734 static const char *get_tracking_branch(const char *remote, const char *refspec)
 735 {
 736         struct refspec_item spec;
 737         const char *spec_src;
 738         const char *merge_branch;
 739
 740         refspec_item_init_or_die(&spec, refspec, REFSPEC_FETCH);
 741         spec_src = spec.src;
 742         if (!*spec_src || !strcmp(spec_src, "HEAD"))
 743                 spec_src = "HEAD";
 744         else if (skip_prefix(spec_src, "heads/", &spec_src))
 745                 ;
 746         else if (skip_prefix(spec_src, "refs/heads/", &spec_src))
 747                 ;
 748         else if (starts_with(spec_src, "refs/") ||
 749                 starts_with(spec_src, "tags/") ||
 750                 starts_with(spec_src, "remotes/"))
 751                 spec_src = "";
 752
 753         if (*spec_src) {
 754                 if (!strcmp(remote, "."))
 755                         merge_branch = mkpath("refs/heads/%s", spec_src);
 756                 else
 757                         merge_branch = mkpath("refs/remotes/%s/%s", remote, spec_src);
 758         } else
 759                 merge_branch = NULL;
 760
 761         refspec_item_clear(&spec);
 762         return merge_branch;
 763 }
 764
 765 /**
 766  * Given the repo and refspecs, sets fork_point to the point at which the
 767  * current branch forked from its remote-tracking branch. Returns 0 on success,
 768  * -1 on failure.
 769  */
 770 static int get_rebase_fork_point(struct object_id *fork_point, const char *repo,
 771                 const char *refspec)
 772 {
 773         int ret;
 774         struct branch *curr_branch;
 775         const char *remote_branch;
 776         struct child_process cp = CHILD_PROCESS_INIT;
 777         struct strbuf sb = STRBUF_INIT;
 778
 779         curr_branch = branch_get("HEAD");
 780         if (!curr_branch)
 781                 return -1;
 782
 783         if (refspec)
 784                 remote_branch = get_tracking_branch(repo, refspec);
 785         else
 786                 remote_branch = get_upstream_branch(repo);
 787
 788         if (!remote_branch)
 789                 return -1;
 790
 791         strvec_pushl(&cp.args, "merge-base", "--fork-point",
 792                      remote_branch, curr_branch->name, NULL);
 793         cp.no_stdin = 1;
 794         cp.no_stderr = 1;
 795         cp.git_cmd = 1;
 796
 797         ret = capture_command(&cp, &sb, GIT_MAX_HEXSZ);
 798         if (ret)
 799                 goto cleanup;
 800
 801         ret = get_oid_hex(sb.buf, fork_point);
 802         if (ret)
 803                 goto cleanup;
 804
 805 cleanup:
 806         strbuf_release(&sb);
 807         return ret ? -1 : 0;
 808 }
 809
 810 /**
 811  * Sets merge_base to the octopus merge base of curr_head, merge_head and
 812  * fork_point. Returns 0 if a merge base is found, 1 otherwise.
 813  */
 814 static int get_octopus_merge_base(struct object_id *merge_base,
 815                 const struct object_id *curr_head,
 816                 const struct object_id *merge_head,
 817                 const struct object_id *fork_point)
 818 {
 819         struct commit_list *revs = NULL, *result = NULL;
 820
 821         commit_list_insert(lookup_commit_reference(the_repository, curr_head),
 822                            &revs);
 823         commit_list_insert(lookup_commit_reference(the_repository, merge_head),
 824                            &revs);
 825         if (!is_null_oid(fork_point))
 826                 commit_list_insert(lookup_commit_reference(the_repository, fork_point),
 827                                    &revs);
 828
 829         if (get_octopus_merge_bases(revs, &result) < 0)
 830                 exit(128);
 831         free_commit_list(revs);
 832         reduce_heads_replace(&result);
 833
 834         if (!result)
 835                 return 1;
 836
 837         oidcpy(merge_base, &result->item->object.oid);
 838         free_commit_list(result);
 839         return 0;
 840 }
 841
 842 /**
 843  * Given the current HEAD oid, the merge head returned from git-fetch and the
 844  * fork point calculated by get_rebase_fork_point(), compute the <newbase> and
 845  * <upstream> arguments to use for the upcoming git-rebase invocation.
 846  */
 847 static int get_rebase_newbase_and_upstream(struct object_id *newbase,
 848                 struct object_id *upstream,
 849                 const struct object_id *curr_head,
 850                 const struct object_id *merge_head,
 851                 const struct object_id *fork_point)
 852 {
 853         struct object_id oct_merge_base;
 854
 855         if (!get_octopus_merge_base(&oct_merge_base, curr_head, merge_head, fork_point))
 856                 if (!is_null_oid(fork_point) && oideq(&oct_merge_base, fork_point))
 857                         fork_point = NULL;
 858
 859         if (fork_point && !is_null_oid(fork_point))
 860                 oidcpy(upstream, fork_point);
 861         else
 862                 oidcpy(upstream, merge_head);
 863
 864         oidcpy(newbase, merge_head);
 865
 866         return 0;
 867 }
 868
 869 /**
 870  * Given the <newbase> and <upstream> calculated by
 871  * get_rebase_newbase_and_upstream(), runs git-rebase with the
 872  * appropriate arguments and returns its exit status.
 873  */
 874 static int run_rebase(const struct object_id *newbase,
 875                 const struct object_id *upstream)
 876 {
 877         struct child_process cmd = CHILD_PROCESS_INIT;
 878
 879         strvec_push(&cmd.args, "rebase");
 880
 881         /* Shared options */
 882         argv_push_verbosity(&cmd.args);
 883
 884         /* Options passed to git-rebase */
 885         if (opt_rebase == REBASE_MERGES)
 886                 strvec_push(&cmd.args, "--rebase-merges");
 887         else if (opt_rebase == REBASE_INTERACTIVE)
 888                 strvec_push(&cmd.args, "--interactive");
 889         if (opt_diffstat)
 890                 strvec_push(&cmd.args, opt_diffstat);
 891         strvec_pushv(&cmd.args, opt_strategies.v);
 892         strvec_pushv(&cmd.args, opt_strategy_opts.v);
 893         if (opt_gpg_sign)
 894                 strvec_push(&cmd.args, opt_gpg_sign);
 895         if (opt_signoff)
 896                 strvec_push(&cmd.args, opt_signoff);
 897         if (opt_autostash == 0)
 898                 strvec_push(&cmd.args, "--no-autostash");
 899         else if (opt_autostash == 1)
 900                 strvec_push(&cmd.args, "--autostash");
 901         if (opt_verify_signatures &&
 902             !strcmp(opt_verify_signatures, "--verify-signatures"))
 903                 warning(_("ignoring --verify-signatures for rebase"));
 904
 905         strvec_push(&cmd.args, "--onto");
 906         strvec_push(&cmd.args, oid_to_hex(newbase));
 907
 908         strvec_push(&cmd.args, oid_to_hex(upstream));
 909
 910         cmd.git_cmd = 1;
 911         return run_command(&cmd);
 912 }
 913
 914 static int get_can_ff(struct object_id *orig_head,
 915                       struct oid_array *merge_heads)
 916 {
 917         int ret;
 918         struct commit_list *list = NULL;
 919         struct commit *merge_head, *head;
 920         struct object_id *orig_merge_head;
 921
 922         if (merge_heads->nr > 1)
 923                 return 0;
 924
 925         orig_merge_head = &merge_heads->oid[0];
 926         head = lookup_commit_reference(the_repository, orig_head);
 927         commit_list_insert(head, &list);
 928         merge_head = lookup_commit_reference(the_repository, orig_merge_head);
 929         ret = repo_is_descendant_of(the_repository, merge_head, list);
 930         free_commit_list(list);
 931         if (ret < 0)
 932                 exit(128);
 933         return ret;
 934 }
 935
 936 /*
 937  * Is orig_head a descendant of _all_ merge_heads?
 938  * Unfortunately is_descendant_of() cannot be used as it asks
 939  * if orig_head is a descendant of at least one of them.
 940  */
 941 static int already_up_to_date(struct object_id *orig_head,
 942                               struct oid_array *merge_heads)
 943 {
 944         int i;
 945         struct commit *ours;
 946
 947         ours = lookup_commit_reference(the_repository, orig_head);
 948         for (i = 0; i < merge_heads->nr; i++) {
 949                 struct commit_list *list = NULL;
 950                 struct commit *theirs;
 951                 int ok;
 952
 953                 theirs = lookup_commit_reference(the_repository, &merge_heads->oid[i]);
 954                 commit_list_insert(theirs, &list);
 955                 ok = repo_is_descendant_of(the_repository, ours, list);
 956                 free_commit_list(list);
 957                 if (ok < 0)
 958                         exit(128);
 959                 if (!ok)
 960                         return 0;
 961         }
 962         return 1;
 963 }
 964
 965 static void show_advice_pull_non_ff(void)
 966 {
 967         advise(_("You have divergent branches and need to specify how to reconcile them.\n"
 968                  "You can do so by running one of the following commands sometime before\n"
 969                  "your next pull:\n"
 970                  "\n"
 971                  "  git config pull.rebase false  # merge\n"
 972                  "  git config pull.rebase true   # rebase\n"
 973                  "  git config pull.ff only       # fast-forward only\n"
 974                  "\n"
 975                  "You can replace \"git config\" with \"git config --global\" to set a default\n"
 976                  "preference for all repositories. You can also pass --rebase, --no-rebase,\n"
 977                  "or --ff-only on the command line to override the configured default per\n"
 978                  "invocation.\n"));
 979 }
 980
 981 int cmd_pull(int argc,
 982              const char **argv,
 983              const char *prefix,
 984              struct repository *repository UNUSED)
 985 {
 986         const char *repo, **refspecs;
 987         struct oid_array merge_heads = OID_ARRAY_INIT;
 988         struct object_id orig_head, curr_head;
 989         struct object_id rebase_fork_point;
 990         int rebase_unspecified = 0;
 991         int can_ff;
 992         int divergent;
 993         int ret;
 994
 995         if (!getenv("GIT_REFLOG_ACTION"))
 996                 set_reflog_message(argc, argv);
 997
 998         git_config(git_pull_config, NULL);
 999         if (the_repository->gitdir) {
1000                 prepare_repo_settings(the_repository);
1001                 the_repository->settings.command_requires_full_index = 0;
1002         }
1003
1004         argc = parse_options(argc, argv, prefix, pull_options, pull_usage, 0);
1005
1006         if (recurse_submodules_cli != RECURSE_SUBMODULES_DEFAULT)
1007                 recurse_submodules = recurse_submodules_cli;
1008
1009         if (cleanup_arg)
1010                 /*
1011                  * this only checks the validity of cleanup_arg; we don't need
1012                  * a valid value for use_editor
1013                  */
1014                 get_cleanup_mode(cleanup_arg, 0);
1015
1016         parse_repo_refspecs(argc, argv, &repo, &refspecs);
1017
1018         if (!opt_ff) {
1019                 opt_ff = xstrdup_or_null(config_get_ff());
1020                 /*
1021                  * A subtle point: opt_ff was set on the line above via
1022                  * reading from config.  opt_rebase, in contrast, is set
1023                  * before this point via command line options.  The setting
1024                  * of opt_rebase via reading from config (using
1025                  * config_get_rebase()) does not happen until later.  We
1026                  * are relying on the next if-condition happening before
1027                  * the config_get_rebase() call so that an explicit
1028                  * "--rebase" can override a config setting of
1029                  * pull.ff=only.
1030                  */
1031                 if (opt_rebase >= 0 && opt_ff && !strcmp(opt_ff, "--ff-only")) {
1032                         free(opt_ff);
1033                         opt_ff = xstrdup("--ff");
1034                 }
1035         }
1036
1037         if (opt_rebase < 0)
1038                 opt_rebase = config_get_rebase(&rebase_unspecified);
1039
1040         if (repo_read_index_unmerged(the_repository))
1041                 die_resolve_conflict("pull");
1042
1043         if (file_exists(git_path_merge_head(the_repository)))
1044                 die_conclude_merge();
1045
1046         if (repo_get_oid(the_repository, "HEAD", &orig_head))
1047                 oidclr(&orig_head, the_repository->hash_algo);
1048
1049         if (opt_rebase) {
1050                 if (opt_autostash == -1)
1051                         opt_autostash = config_autostash;
1052
1053                 if (is_null_oid(&orig_head) && !is_index_unborn(the_repository->index))
1054                         die(_("Updating an unborn branch with changes added to the index."));
1055
1056                 if (!opt_autostash)
1057                         require_clean_work_tree(the_repository,
1058                                 N_("pull with rebase"),
1059                                 _("Please commit or stash them."), 1, 0);
1060
1061                 if (get_rebase_fork_point(&rebase_fork_point, repo, *refspecs))
1062                         oidclr(&rebase_fork_point, the_repository->hash_algo);
1063         }
1064
1065         if (run_fetch(repo, refspecs))
1066                 return 1;
1067
1068         if (opt_dry_run)
1069                 return 0;
1070
1071         if (repo_get_oid(the_repository, "HEAD", &curr_head))
1072                 oidclr(&curr_head, the_repository->hash_algo);
1073
1074         if (!is_null_oid(&orig_head) && !is_null_oid(&curr_head) &&
1075                         !oideq(&orig_head, &curr_head)) {
1076                 /*
1077                  * The fetch involved updating the current branch.
1078                  *
1079                  * The working tree and the index file are still based on
1080                  * orig_head commit, but we are merging into curr_head.
1081                  * Update the working tree to match curr_head.
1082                  */
1083
1084                 warning(_("fetch updated the current branch head.\n"
1085                         "fast-forwarding your working tree from\n"
1086                         "commit %s."), oid_to_hex(&orig_head));
1087
1088                 if (checkout_fast_forward(the_repository, &orig_head,
1089                                           &curr_head, 0))
1090                         die(_("Cannot fast-forward your working tree.\n"
1091                                 "After making sure that you saved anything precious from\n"
1092                                 "$ git diff %s\n"
1093                                 "output, run\n"
1094                                 "$ git reset --hard\n"
1095                                 "to recover."), oid_to_hex(&orig_head));
1096         }
1097
1098         get_merge_heads(&merge_heads);
1099
1100         if (!merge_heads.nr)
1101                 die_no_merge_candidates(repo, refspecs);
1102
1103         if (is_null_oid(&orig_head)) {
1104                 if (merge_heads.nr > 1)
1105                         die(_("Cannot merge multiple branches into empty head."));
1106                 ret = pull_into_void(merge_heads.oid, &curr_head);
1107                 goto cleanup;
1108         }
1109         if (merge_heads.nr > 1) {
1110                 if (opt_rebase)
1111                         die(_("Cannot rebase onto multiple branches."));
1112                 if (opt_ff && !strcmp(opt_ff, "--ff-only"))
1113                         die(_("Cannot fast-forward to multiple branches."));
1114         }
1115
1116         can_ff = get_can_ff(&orig_head, &merge_heads);
1117         divergent = !can_ff && !already_up_to_date(&orig_head, &merge_heads);
1118
1119         /* ff-only takes precedence over rebase */
1120         if (opt_ff && !strcmp(opt_ff, "--ff-only")) {
1121                 if (divergent)
1122                         die_ff_impossible();
1123                 opt_rebase = REBASE_FALSE;
1124         }
1125         /* If no action specified and we can't fast forward, then warn. */
1126         if (!opt_ff && rebase_unspecified && divergent) {
1127                 show_advice_pull_non_ff();
1128                 die(_("Need to specify how to reconcile divergent branches."));
1129         }
1130
1131         if (opt_rebase) {
1132                 struct object_id newbase;
1133                 struct object_id upstream;
1134                 get_rebase_newbase_and_upstream(&newbase, &upstream, &curr_head,
1135                                                 merge_heads.oid, &rebase_fork_point);
1136
1137                 if ((recurse_submodules == RECURSE_SUBMODULES_ON ||
1138                      recurse_submodules == RECURSE_SUBMODULES_ON_DEMAND) &&
1139                     submodule_touches_in_range(the_repository, &upstream, &curr_head))
1140                         die(_("cannot rebase with locally recorded submodule modifications"));
1141
1142                 if (can_ff) {
1143                         /* we can fast-forward this without invoking rebase */
1144                         free(opt_ff);
1145                         opt_ff = xstrdup("--ff-only");
1146                         ret = run_merge();
1147                 } else {
1148                         ret = run_rebase(&newbase, &upstream);
1149                 }
1150
1151                 if (!ret && (recurse_submodules == RECURSE_SUBMODULES_ON ||
1152                              recurse_submodules == RECURSE_SUBMODULES_ON_DEMAND))
1153                         ret = rebase_submodules();
1154
1155                 goto cleanup;
1156         } else {
1157                 ret = run_merge();
1158                 if (!ret && (recurse_submodules == RECURSE_SUBMODULES_ON ||
1159                              recurse_submodules == RECURSE_SUBMODULES_ON_DEMAND))
1160                         ret = update_submodules();
1161                 goto cleanup;
1162         }
1163
1164 cleanup:
1165         oid_array_clear(&merge_heads);
1166         return ret;
1167 }