builtin/pull.c

   1 /*
   2  * Builtin "git pull"
   3  *
   4  * Based on git-pull.sh by Junio C Hamano
   5  *
   6  * Fetch one or more remote refs and merge it/them into the current HEAD.
   7  */
   8 #include "cache.h"
   9 #include "builtin.h"
  10 #include "parse-options.h"
  11 #include "exec_cmd.h"
  12 #include "run-command.h"
  13 #include "sha1-array.h"
  14 #include "remote.h"
  15 #include "dir.h"
  16 #include "refs.h"
  17
  18 static const char * const pull_usage[] = {
  19         N_("git pull [options] [<repository> [<refspec>...]]"),
  20         NULL
  21 };
  22
  23 /* Shared options */
  24 static int opt_verbosity;
  25 static char *opt_progress;
  26
  27 /* Options passed to git-merge */
  28 static char *opt_diffstat;
  29 static char *opt_log;
  30 static char *opt_squash;
  31 static char *opt_commit;
  32 static char *opt_edit;
  33 static char *opt_ff;
  34 static char *opt_verify_signatures;
  35 static struct argv_array opt_strategies = ARGV_ARRAY_INIT;
  36 static struct argv_array opt_strategy_opts = ARGV_ARRAY_INIT;
  37 static char *opt_gpg_sign;
  38
  39 /* Options passed to git-fetch */
  40 static char *opt_all;
  41 static char *opt_append;
  42 static char *opt_upload_pack;
  43 static int opt_force;
  44 static char *opt_tags;
  45 static char *opt_prune;
  46 static char *opt_recurse_submodules;
  47 static int opt_dry_run;
  48 static char *opt_keep;
  49 static char *opt_depth;
  50 static char *opt_unshallow;
  51 static char *opt_update_shallow;
  52 static char *opt_refmap;
  53
  54 static struct option pull_options[] = {
  55         /* Shared options */
  56         OPT__VERBOSITY(&opt_verbosity),
  57         OPT_PASSTHRU(0, "progress", &opt_progress, NULL,
  58                 N_("force progress reporting"),
  59                 PARSE_OPT_NOARG),
  60
  61         /* Options passed to git-merge */
  62         OPT_GROUP(N_("Options related to merging")),
  63         OPT_PASSTHRU('n', NULL, &opt_diffstat, NULL,
  64                 N_("do not show a diffstat at the end of the merge"),
  65                 PARSE_OPT_NOARG | PARSE_OPT_NONEG),
  66         OPT_PASSTHRU(0, "stat", &opt_diffstat, NULL,
  67                 N_("show a diffstat at the end of the merge"),
  68                 PARSE_OPT_NOARG),
  69         OPT_PASSTHRU(0, "summary", &opt_diffstat, NULL,
  70                 N_("(synonym to --stat)"),
  71                 PARSE_OPT_NOARG | PARSE_OPT_HIDDEN),
  72         OPT_PASSTHRU(0, "log", &opt_log, N_("n"),
  73                 N_("add (at most <n>) entries from shortlog to merge commit message"),
  74                 PARSE_OPT_OPTARG),
  75         OPT_PASSTHRU(0, "squash", &opt_squash, NULL,
  76                 N_("create a single commit instead of doing a merge"),
  77                 PARSE_OPT_NOARG),
  78         OPT_PASSTHRU(0, "commit", &opt_commit, NULL,
  79                 N_("perform a commit if the merge succeeds (default)"),
  80                 PARSE_OPT_NOARG),
  81         OPT_PASSTHRU(0, "edit", &opt_edit, NULL,
  82                 N_("edit message before committing"),
  83                 PARSE_OPT_NOARG),
  84         OPT_PASSTHRU(0, "ff", &opt_ff, NULL,
  85                 N_("allow fast-forward"),
  86                 PARSE_OPT_NOARG),
  87         OPT_PASSTHRU(0, "ff-only", &opt_ff, NULL,
  88                 N_("abort if fast-forward is not possible"),
  89                 PARSE_OPT_NOARG | PARSE_OPT_NONEG),
  90         OPT_PASSTHRU(0, "verify-signatures", &opt_verify_signatures, NULL,
  91                 N_("verify that the named commit has a valid GPG signature"),
  92                 PARSE_OPT_NOARG),
  93         OPT_PASSTHRU_ARGV('s', "strategy", &opt_strategies, N_("strategy"),
  94                 N_("merge strategy to use"),
  95                 0),
  96         OPT_PASSTHRU_ARGV('X', "strategy-option", &opt_strategy_opts,
  97                 N_("option=value"),
  98                 N_("option for selected merge strategy"),
  99                 0),
 100         OPT_PASSTHRU('S', "gpg-sign", &opt_gpg_sign, N_("key-id"),
 101                 N_("GPG sign commit"),
 102                 PARSE_OPT_OPTARG),
 103
 104         /* Options passed to git-fetch */
 105         OPT_GROUP(N_("Options related to fetching")),
 106         OPT_PASSTHRU(0, "all", &opt_all, NULL,
 107                 N_("fetch from all remotes"),
 108                 PARSE_OPT_NOARG),
 109         OPT_PASSTHRU('a', "append", &opt_append, NULL,
 110                 N_("append to .git/FETCH_HEAD instead of overwriting"),
 111                 PARSE_OPT_NOARG),
 112         OPT_PASSTHRU(0, "upload-pack", &opt_upload_pack, N_("path"),
 113                 N_("path to upload pack on remote end"),
 114                 0),
 115         OPT__FORCE(&opt_force, N_("force overwrite of local branch")),
 116         OPT_PASSTHRU('t', "tags", &opt_tags, NULL,
 117                 N_("fetch all tags and associated objects"),
 118                 PARSE_OPT_NOARG),
 119         OPT_PASSTHRU('p', "prune", &opt_prune, NULL,
 120                 N_("prune remote-tracking branches no longer on remote"),
 121                 PARSE_OPT_NOARG),
 122         OPT_PASSTHRU(0, "recurse-submodules", &opt_recurse_submodules,
 123                 N_("on-demand"),
 124                 N_("control recursive fetching of submodules"),
 125                 PARSE_OPT_OPTARG),
 126         OPT_BOOL(0, "dry-run", &opt_dry_run,
 127                 N_("dry run")),
 128         OPT_PASSTHRU('k', "keep", &opt_keep, NULL,
 129                 N_("keep downloaded pack"),
 130                 PARSE_OPT_NOARG),
 131         OPT_PASSTHRU(0, "depth", &opt_depth, N_("depth"),
 132                 N_("deepen history of shallow clone"),
 133                 0),
 134         OPT_PASSTHRU(0, "unshallow", &opt_unshallow, NULL,
 135                 N_("convert to a complete repository"),
 136                 PARSE_OPT_NONEG | PARSE_OPT_NOARG),
 137         OPT_PASSTHRU(0, "update-shallow", &opt_update_shallow, NULL,
 138                 N_("accept refs that update .git/shallow"),
 139                 PARSE_OPT_NOARG),
 140         OPT_PASSTHRU(0, "refmap", &opt_refmap, N_("refmap"),
 141                 N_("specify fetch refmap"),
 142                 PARSE_OPT_NONEG),
 143
 144         OPT_END()
 145 };
 146
 147 /**
 148  * Pushes "-q" or "-v" switches into arr to match the opt_verbosity level.
 149  */
 150 static void argv_push_verbosity(struct argv_array *arr)
 151 {
 152         int verbosity;
 153
 154         for (verbosity = opt_verbosity; verbosity > 0; verbosity--)
 155                 argv_array_push(arr, "-v");
 156
 157         for (verbosity = opt_verbosity; verbosity < 0; verbosity++)
 158                 argv_array_push(arr, "-q");
 159 }
 160
 161 /**
 162  * Pushes "-f" switches into arr to match the opt_force level.
 163  */
 164 static void argv_push_force(struct argv_array *arr)
 165 {
 166         int force = opt_force;
 167         while (force-- > 0)
 168                 argv_array_push(arr, "-f");
 169 }
 170
 171 /**
 172  * Sets the GIT_REFLOG_ACTION environment variable to the concatenation of argv
 173  */
 174 static void set_reflog_message(int argc, const char **argv)
 175 {
 176         int i;
 177         struct strbuf msg = STRBUF_INIT;
 178
 179         for (i = 0; i < argc; i++) {
 180                 if (i)
 181                         strbuf_addch(&msg, ' ');
 182                 strbuf_addstr(&msg, argv[i]);
 183         }
 184
 185         setenv("GIT_REFLOG_ACTION", msg.buf, 0);
 186
 187         strbuf_release(&msg);
 188 }
 189
 190 /**
 191  * If pull.ff is unset, returns NULL. If pull.ff is "true", returns "--ff". If
 192  * pull.ff is "false", returns "--no-ff". If pull.ff is "only", returns
 193  * "--ff-only". Otherwise, if pull.ff is set to an invalid value, die with an
 194  * error.
 195  */
 196 static const char *config_get_ff(void)
 197 {
 198         const char *value;
 199
 200         if (git_config_get_value("pull.ff", &value))
 201                 return NULL;
 202
 203         switch (git_config_maybe_bool("pull.ff", value)) {
 204         case 0:
 205                 return "--no-ff";
 206         case 1:
 207                 return "--ff";
 208         }
 209
 210         if (!strcmp(value, "only"))
 211                 return "--ff-only";
 212
 213         die(_("Invalid value for pull.ff: %s"), value);
 214 }
 215
 216 /**
 217  * Appends merge candidates from FETCH_HEAD that are not marked not-for-merge
 218  * into merge_heads.
 219  */
 220 static void get_merge_heads(struct sha1_array *merge_heads)
 221 {
 222         const char *filename = git_path("FETCH_HEAD");
 223         FILE *fp;
 224         struct strbuf sb = STRBUF_INIT;
 225         unsigned char sha1[GIT_SHA1_RAWSZ];
 226
 227         if (!(fp = fopen(filename, "r")))
 228                 die_errno(_("could not open '%s' for reading"), filename);
 229         while (strbuf_getline(&sb, fp, '\n') != EOF) {
 230                 if (get_sha1_hex(sb.buf, sha1))
 231                         continue;  /* invalid line: does not start with SHA1 */
 232                 if (starts_with(sb.buf + GIT_SHA1_HEXSZ, "\tnot-for-merge\t"))
 233                         continue;  /* ref is not-for-merge */
 234                 sha1_array_append(merge_heads, sha1);
 235         }
 236         fclose(fp);
 237         strbuf_release(&sb);
 238 }
 239
 240 /**
 241  * Used by die_no_merge_candidates() as a for_each_remote() callback to
 242  * retrieve the name of the remote if the repository only has one remote.
 243  */
 244 static int get_only_remote(struct remote *remote, void *cb_data)
 245 {
 246         const char **remote_name = cb_data;
 247
 248         if (*remote_name)
 249                 return -1;
 250
 251         *remote_name = remote->name;
 252         return 0;
 253 }
 254
 255 /**
 256  * Dies with the appropriate reason for why there are no merge candidates:
 257  *
 258  * 1. We fetched from a specific remote, and a refspec was given, but it ended
 259  *    up not fetching anything. This is usually because the user provided a
 260  *    wildcard refspec which had no matches on the remote end.
 261  *
 262  * 2. We fetched from a non-default remote, but didn't specify a branch to
 263  *    merge. We can't use the configured one because it applies to the default
 264  *    remote, thus the user must specify the branches to merge.
 265  *
 266  * 3. We fetched from the branch's or repo's default remote, but:
 267  *
 268  *    a. We are not on a branch, so there will never be a configured branch to
 269  *       merge with.
 270  *
 271  *    b. We are on a branch, but there is no configured branch to merge with.
 272  *
 273  * 4. We fetched from the branch's or repo's default remote, but the configured
 274  *    branch to merge didn't get fetched. (Either it doesn't exist, or wasn't
 275  *    part of the configured fetch refspec.)
 276  */
 277 static void NORETURN die_no_merge_candidates(const char *repo, const char **refspecs)
 278 {
 279         struct branch *curr_branch = branch_get("HEAD");
 280         const char *remote = curr_branch ? curr_branch->remote_name : NULL;
 281
 282         if (*refspecs) {
 283                 fprintf_ln(stderr, _("There are no candidates for merging among the refs that you just fetched."));
 284                 fprintf_ln(stderr, _("Generally this means that you provided a wildcard refspec which had no\n"
 285                                         "matches on the remote end."));
 286         } else if (repo && curr_branch && (!remote || strcmp(repo, remote))) {
 287                 fprintf_ln(stderr, _("You asked to pull from the remote '%s', but did not specify\n"
 288                         "a branch. Because this is not the default configured remote\n"
 289                         "for your current branch, you must specify a branch on the command line."),
 290                         repo);
 291         } else if (!curr_branch) {
 292                 fprintf_ln(stderr, _("You are not currently on a branch."));
 293                 fprintf_ln(stderr, _("Please specify which branch you want to merge with."));
 294                 fprintf_ln(stderr, _("See git-pull(1) for details."));
 295                 fprintf(stderr, "\n");
 296                 fprintf_ln(stderr, "    git pull <remote> <branch>");
 297                 fprintf(stderr, "\n");
 298         } else if (!curr_branch->merge_nr) {
 299                 const char *remote_name = NULL;
 300
 301                 if (for_each_remote(get_only_remote, &remote_name) || !remote_name)
 302                         remote_name = "<remote>";
 303
 304                 fprintf_ln(stderr, _("There is no tracking information for the current branch."));
 305                 fprintf_ln(stderr, _("Please specify which branch you want to merge with."));
 306                 fprintf_ln(stderr, _("See git-pull(1) for details."));
 307                 fprintf(stderr, "\n");
 308                 fprintf_ln(stderr, "    git pull <remote> <branch>");
 309                 fprintf(stderr, "\n");
 310                 fprintf_ln(stderr, _("If you wish to set tracking information for this branch you can do so with:\n"
 311                                 "\n"
 312                                 "    git branch --set-upstream-to=%s/<branch> %s\n"),
 313                                 remote_name, curr_branch->name);
 314         } else
 315                 fprintf_ln(stderr, _("Your configuration specifies to merge with the ref '%s'\n"
 316                         "from the remote, but no such ref was fetched."),
 317                         *curr_branch->merge_name);
 318         exit(1);
 319 }
 320
 321 /**
 322  * Parses argv into [<repo> [<refspecs>...]], returning their values in `repo`
 323  * as a string and `refspecs` as a null-terminated array of strings. If `repo`
 324  * is not provided in argv, it is set to NULL.
 325  */
 326 static void parse_repo_refspecs(int argc, const char **argv, const char **repo,
 327                 const char ***refspecs)
 328 {
 329         if (argc > 0) {
 330                 *repo = *argv++;
 331                 argc--;
 332         } else
 333                 *repo = NULL;
 334         *refspecs = argv;
 335 }
 336
 337 /**
 338  * Runs git-fetch, returning its exit status. `repo` and `refspecs` are the
 339  * repository and refspecs to fetch, or NULL if they are not provided.
 340  */
 341 static int run_fetch(const char *repo, const char **refspecs)
 342 {
 343         struct argv_array args = ARGV_ARRAY_INIT;
 344         int ret;
 345
 346         argv_array_pushl(&args, "fetch", "--update-head-ok", NULL);
 347
 348         /* Shared options */
 349         argv_push_verbosity(&args);
 350         if (opt_progress)
 351                 argv_array_push(&args, opt_progress);
 352
 353         /* Options passed to git-fetch */
 354         if (opt_all)
 355                 argv_array_push(&args, opt_all);
 356         if (opt_append)
 357                 argv_array_push(&args, opt_append);
 358         if (opt_upload_pack)
 359                 argv_array_push(&args, opt_upload_pack);
 360         argv_push_force(&args);
 361         if (opt_tags)
 362                 argv_array_push(&args, opt_tags);
 363         if (opt_prune)
 364                 argv_array_push(&args, opt_prune);
 365         if (opt_recurse_submodules)
 366                 argv_array_push(&args, opt_recurse_submodules);
 367         if (opt_dry_run)
 368                 argv_array_push(&args, "--dry-run");
 369         if (opt_keep)
 370                 argv_array_push(&args, opt_keep);
 371         if (opt_depth)
 372                 argv_array_push(&args, opt_depth);
 373         if (opt_unshallow)
 374                 argv_array_push(&args, opt_unshallow);
 375         if (opt_update_shallow)
 376                 argv_array_push(&args, opt_update_shallow);
 377         if (opt_refmap)
 378                 argv_array_push(&args, opt_refmap);
 379
 380         if (repo) {
 381                 argv_array_push(&args, repo);
 382                 argv_array_pushv(&args, refspecs);
 383         } else if (*refspecs)
 384                 die("BUG: refspecs without repo?");
 385         ret = run_command_v_opt(args.argv, RUN_GIT_CMD);
 386         argv_array_clear(&args);
 387         return ret;
 388 }
 389
 390 /**
 391  * "Pulls into void" by branching off merge_head.
 392  */
 393 static int pull_into_void(const unsigned char *merge_head,
 394                 const unsigned char *curr_head)
 395 {
 396         /*
 397          * Two-way merge: we treat the index as based on an empty tree,
 398          * and try to fast-forward to HEAD. This ensures we will not lose
 399          * index/worktree changes that the user already made on the unborn
 400          * branch.
 401          */
 402         if (checkout_fast_forward(EMPTY_TREE_SHA1_BIN, merge_head, 0))
 403                 return 1;
 404
 405         if (update_ref("initial pull", "HEAD", merge_head, curr_head, 0, UPDATE_REFS_DIE_ON_ERR))
 406                 return 1;
 407
 408         return 0;
 409 }
 410
 411 /**
 412  * Runs git-merge, returning its exit status.
 413  */
 414 static int run_merge(void)
 415 {
 416         int ret;
 417         struct argv_array args = ARGV_ARRAY_INIT;
 418
 419         argv_array_pushl(&args, "merge", NULL);
 420
 421         /* Shared options */
 422         argv_push_verbosity(&args);
 423         if (opt_progress)
 424                 argv_array_push(&args, opt_progress);
 425
 426         /* Options passed to git-merge */
 427         if (opt_diffstat)
 428                 argv_array_push(&args, opt_diffstat);
 429         if (opt_log)
 430                 argv_array_push(&args, opt_log);
 431         if (opt_squash)
 432                 argv_array_push(&args, opt_squash);
 433         if (opt_commit)
 434                 argv_array_push(&args, opt_commit);
 435         if (opt_edit)
 436                 argv_array_push(&args, opt_edit);
 437         if (opt_ff)
 438                 argv_array_push(&args, opt_ff);
 439         if (opt_verify_signatures)
 440                 argv_array_push(&args, opt_verify_signatures);
 441         argv_array_pushv(&args, opt_strategies.argv);
 442         argv_array_pushv(&args, opt_strategy_opts.argv);
 443         if (opt_gpg_sign)
 444                 argv_array_push(&args, opt_gpg_sign);
 445
 446         argv_array_push(&args, "FETCH_HEAD");
 447         ret = run_command_v_opt(args.argv, RUN_GIT_CMD);
 448         argv_array_clear(&args);
 449         return ret;
 450 }
 451
 452 int cmd_pull(int argc, const char **argv, const char *prefix)
 453 {
 454         const char *repo, **refspecs;
 455         struct sha1_array merge_heads = SHA1_ARRAY_INIT;
 456         unsigned char orig_head[GIT_SHA1_RAWSZ], curr_head[GIT_SHA1_RAWSZ];
 457
 458         if (!getenv("_GIT_USE_BUILTIN_PULL")) {
 459                 const char *path = mkpath("%s/git-pull", git_exec_path());
 460
 461                 if (sane_execvp(path, (char **)argv) < 0)
 462                         die_errno("could not exec %s", path);
 463         }
 464
 465         if (!getenv("GIT_REFLOG_ACTION"))
 466                 set_reflog_message(argc, argv);
 467
 468         argc = parse_options(argc, argv, prefix, pull_options, pull_usage, 0);
 469
 470         parse_repo_refspecs(argc, argv, &repo, &refspecs);
 471
 472         if (!opt_ff)
 473                 opt_ff = xstrdup_or_null(config_get_ff());
 474
 475         git_config(git_default_config, NULL);
 476
 477         if (read_cache_unmerged())
 478                 die_resolve_conflict("Pull");
 479
 480         if (file_exists(git_path("MERGE_HEAD")))
 481                 die_conclude_merge();
 482
 483         if (get_sha1("HEAD", orig_head))
 484                 hashclr(orig_head);
 485
 486         if (run_fetch(repo, refspecs))
 487                 return 1;
 488
 489         if (opt_dry_run)
 490                 return 0;
 491
 492         if (get_sha1("HEAD", curr_head))
 493                 hashclr(curr_head);
 494
 495         if (!is_null_sha1(orig_head) && !is_null_sha1(curr_head) &&
 496                         hashcmp(orig_head, curr_head)) {
 497                 /*
 498                  * The fetch involved updating the current branch.
 499                  *
 500                  * The working tree and the index file are still based on
 501                  * orig_head commit, but we are merging into curr_head.
 502                  * Update the working tree to match curr_head.
 503                  */
 504
 505                 warning(_("fetch updated the current branch head.\n"
 506                         "fast-forwarding your working tree from\n"
 507                         "commit %s."), sha1_to_hex(orig_head));
 508
 509                 if (checkout_fast_forward(orig_head, curr_head, 0))
 510                         die(_("Cannot fast-forward your working tree.\n"
 511                                 "After making sure that you saved anything precious from\n"
 512                                 "$ git diff %s\n"
 513                                 "output, run\n"
 514                                 "$ git reset --hard\n"
 515                                 "to recover."), sha1_to_hex(orig_head));
 516         }
 517
 518         get_merge_heads(&merge_heads);
 519
 520         if (!merge_heads.nr)
 521                 die_no_merge_candidates(repo, refspecs);
 522
 523         if (is_null_sha1(orig_head)) {
 524                 if (merge_heads.nr > 1)
 525                         die(_("Cannot merge multiple branches into empty head."));
 526                 return pull_into_void(*merge_heads.sha1, curr_head);
 527         } else
 528                 return run_merge();
 529 }