Andrew's git / gitweb.git / builtin/rebase.c
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builtin / rebase.con commit Merge branch 'pk/rebase-in-c-2-basic' (e0720a3)
   1/*
   2 * "git rebase" builtin command
   3 *
   4 * Copyright (c) 2018 Pratik Karki
   5 */
   6
   7#include "builtin.h"
   8#include "run-command.h"
   9#include "exec-cmd.h"
  10#include "argv-array.h"
  11#include "dir.h"
  12#include "packfile.h"
  13#include "refs.h"
  14#include "quote.h"
  15#include "config.h"
  16#include "cache-tree.h"
  17#include "unpack-trees.h"
  18#include "lockfile.h"
  19#include "parse-options.h"
  20#include "commit.h"
  21#include "diff.h"
  22#include "wt-status.h"
  23#include "revision.h"
  24#include "commit-reach.h"
  25
  26static char const * const builtin_rebase_usage[] = {
  27        N_("git rebase [-i] [options] [--exec <cmd>] [--onto <newbase>] "
  28                "[<upstream>] [<branch>]"),
  29        N_("git rebase [-i] [options] [--exec <cmd>] [--onto <newbase>] "
  30                "--root [<branch>]"),
  31        N_("git rebase --continue | --abort | --skip | --edit-todo"),
  32        NULL
  33};
  34
  35static GIT_PATH_FUNC(apply_dir, "rebase-apply")
  36static GIT_PATH_FUNC(merge_dir, "rebase-merge")
  37
  38enum rebase_type {
  39        REBASE_UNSPECIFIED = -1,
  40        REBASE_AM,
  41        REBASE_MERGE,
  42        REBASE_INTERACTIVE,
  43        REBASE_PRESERVE_MERGES
  44};
  45
  46static int use_builtin_rebase(void)
  47{
  48        struct child_process cp = CHILD_PROCESS_INIT;
  49        struct strbuf out = STRBUF_INIT;
  50        int ret;
  51
  52        argv_array_pushl(&cp.args,
  53                         "config", "--bool", "rebase.usebuiltin", NULL);
  54        cp.git_cmd = 1;
  55        if (capture_command(&cp, &out, 6)) {
  56                strbuf_release(&out);
  57                return 0;
  58        }
  59
  60        strbuf_trim(&out);
  61        ret = !strcmp("true", out.buf);
  62        strbuf_release(&out);
  63        return ret;
  64}
  65
  66static int apply_autostash(void)
  67{
  68        warning("TODO");
  69        return 0;
  70}
  71
  72struct rebase_options {
  73        enum rebase_type type;
  74        const char *state_dir;
  75        struct commit *upstream;
  76        const char *upstream_name;
  77        const char *upstream_arg;
  78        char *head_name;
  79        struct object_id orig_head;
  80        struct commit *onto;
  81        const char *onto_name;
  82        const char *revisions;
  83        const char *switch_to;
  84        int root;
  85        struct commit *restrict_revision;
  86        int dont_finish_rebase;
  87        enum {
  88                REBASE_NO_QUIET = 1<<0,
  89                REBASE_VERBOSE = 1<<1,
  90                REBASE_DIFFSTAT = 1<<2,
  91                REBASE_FORCE = 1<<3,
  92                REBASE_INTERACTIVE_EXPLICIT = 1<<4,
  93        } flags;
  94        struct strbuf git_am_opt;
  95};
  96
  97static int is_interactive(struct rebase_options *opts)
  98{
  99        return opts->type == REBASE_INTERACTIVE ||
 100                opts->type == REBASE_PRESERVE_MERGES;
 101}
 102
 103/* Returns the filename prefixed by the state_dir */
 104static const char *state_dir_path(const char *filename, struct rebase_options *opts)
 105{
 106        static struct strbuf path = STRBUF_INIT;
 107        static size_t prefix_len;
 108
 109        if (!prefix_len) {
 110                strbuf_addf(&path, "%s/", opts->state_dir);
 111                prefix_len = path.len;
 112        }
 113
 114        strbuf_setlen(&path, prefix_len);
 115        strbuf_addstr(&path, filename);
 116        return path.buf;
 117}
 118
 119static int finish_rebase(struct rebase_options *opts)
 120{
 121        struct strbuf dir = STRBUF_INIT;
 122        const char *argv_gc_auto[] = { "gc", "--auto", NULL };
 123
 124        delete_ref(NULL, "REBASE_HEAD", NULL, REF_NO_DEREF);
 125        apply_autostash();
 126        close_all_packs(the_repository->objects);
 127        /*
 128         * We ignore errors in 'gc --auto', since the
 129         * user should see them.
 130         */
 131        run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
 132        strbuf_addstr(&dir, opts->state_dir);
 133        remove_dir_recursively(&dir, 0);
 134        strbuf_release(&dir);
 135
 136        return 0;
 137}
 138
 139static struct commit *peel_committish(const char *name)
 140{
 141        struct object *obj;
 142        struct object_id oid;
 143
 144        if (get_oid(name, &oid))
 145                return NULL;
 146        obj = parse_object(the_repository, &oid);
 147        return (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
 148}
 149
 150static void add_var(struct strbuf *buf, const char *name, const char *value)
 151{
 152        if (!value)
 153                strbuf_addf(buf, "unset %s; ", name);
 154        else {
 155                strbuf_addf(buf, "%s=", name);
 156                sq_quote_buf(buf, value);
 157                strbuf_addstr(buf, "; ");
 158        }
 159}
 160
 161static int run_specific_rebase(struct rebase_options *opts)
 162{
 163        const char *argv[] = { NULL, NULL };
 164        struct strbuf script_snippet = STRBUF_INIT;
 165        int status;
 166        const char *backend, *backend_func;
 167
 168        add_var(&script_snippet, "GIT_DIR", absolute_path(get_git_dir()));
 169        add_var(&script_snippet, "state_dir", opts->state_dir);
 170
 171        add_var(&script_snippet, "upstream_name", opts->upstream_name);
 172        add_var(&script_snippet, "upstream",
 173                                 oid_to_hex(&opts->upstream->object.oid));
 174        add_var(&script_snippet, "head_name",
 175                opts->head_name ? opts->head_name : "detached HEAD");
 176        add_var(&script_snippet, "orig_head", oid_to_hex(&opts->orig_head));
 177        add_var(&script_snippet, "onto", oid_to_hex(&opts->onto->object.oid));
 178        add_var(&script_snippet, "onto_name", opts->onto_name);
 179        add_var(&script_snippet, "revisions", opts->revisions);
 180        add_var(&script_snippet, "restrict_revision", opts->restrict_revision ?
 181                oid_to_hex(&opts->restrict_revision->object.oid) : NULL);
 182        add_var(&script_snippet, "GIT_QUIET",
 183                opts->flags & REBASE_NO_QUIET ? "" : "t");
 184        add_var(&script_snippet, "git_am_opt", opts->git_am_opt.buf);
 185        add_var(&script_snippet, "verbose",
 186                opts->flags & REBASE_VERBOSE ? "t" : "");
 187        add_var(&script_snippet, "diffstat",
 188                opts->flags & REBASE_DIFFSTAT ? "t" : "");
 189        add_var(&script_snippet, "force_rebase",
 190                opts->flags & REBASE_FORCE ? "t" : "");
 191        if (opts->switch_to)
 192                add_var(&script_snippet, "switch_to", opts->switch_to);
 193
 194        switch (opts->type) {
 195        case REBASE_AM:
 196                backend = "git-rebase--am";
 197                backend_func = "git_rebase__am";
 198                break;
 199        case REBASE_INTERACTIVE:
 200                backend = "git-rebase--interactive";
 201                backend_func = "git_rebase__interactive";
 202                break;
 203        case REBASE_MERGE:
 204                backend = "git-rebase--merge";
 205                backend_func = "git_rebase__merge";
 206                break;
 207        case REBASE_PRESERVE_MERGES:
 208                backend = "git-rebase--preserve-merges";
 209                backend_func = "git_rebase__preserve_merges";
 210                break;
 211        default:
 212                BUG("Unhandled rebase type %d", opts->type);
 213                break;
 214        }
 215
 216        strbuf_addf(&script_snippet,
 217                    ". git-sh-setup && . git-rebase--common &&"
 218                    " . %s && %s", backend, backend_func);
 219        argv[0] = script_snippet.buf;
 220
 221        status = run_command_v_opt(argv, RUN_USING_SHELL);
 222        if (opts->dont_finish_rebase)
 223                ; /* do nothing */
 224        else if (status == 0) {
 225                if (!file_exists(state_dir_path("stopped-sha", opts)))
 226                        finish_rebase(opts);
 227        } else if (status == 2) {
 228                struct strbuf dir = STRBUF_INIT;
 229
 230                apply_autostash();
 231                strbuf_addstr(&dir, opts->state_dir);
 232                remove_dir_recursively(&dir, 0);
 233                strbuf_release(&dir);
 234                die("Nothing to do");
 235        }
 236
 237        strbuf_release(&script_snippet);
 238
 239        return status ? -1 : 0;
 240}
 241
 242#define GIT_REFLOG_ACTION_ENVIRONMENT "GIT_REFLOG_ACTION"
 243
 244static int reset_head(struct object_id *oid, const char *action,
 245                      const char *switch_to_branch, int detach_head)
 246{
 247        struct object_id head_oid;
 248        struct tree_desc desc;
 249        struct lock_file lock = LOCK_INIT;
 250        struct unpack_trees_options unpack_tree_opts;
 251        struct tree *tree;
 252        const char *reflog_action;
 253        struct strbuf msg = STRBUF_INIT;
 254        size_t prefix_len;
 255        struct object_id *orig = NULL, oid_orig,
 256                *old_orig = NULL, oid_old_orig;
 257        int ret = 0;
 258
 259        if (switch_to_branch && !starts_with(switch_to_branch, "refs/"))
 260                BUG("Not a fully qualified branch: '%s'", switch_to_branch);
 261
 262        if (hold_locked_index(&lock, LOCK_REPORT_ON_ERROR) < 0)
 263                return -1;
 264
 265        if (!oid) {
 266                if (get_oid("HEAD", &head_oid)) {
 267                        rollback_lock_file(&lock);
 268                        return error(_("could not determine HEAD revision"));
 269                }
 270                oid = &head_oid;
 271        }
 272
 273        memset(&unpack_tree_opts, 0, sizeof(unpack_tree_opts));
 274        setup_unpack_trees_porcelain(&unpack_tree_opts, action);
 275        unpack_tree_opts.head_idx = 1;
 276        unpack_tree_opts.src_index = the_repository->index;
 277        unpack_tree_opts.dst_index = the_repository->index;
 278        unpack_tree_opts.fn = oneway_merge;
 279        unpack_tree_opts.update = 1;
 280        unpack_tree_opts.merge = 1;
 281        if (!detach_head)
 282                unpack_tree_opts.reset = 1;
 283
 284        if (read_index_unmerged(the_repository->index) < 0) {
 285                rollback_lock_file(&lock);
 286                return error(_("could not read index"));
 287        }
 288
 289        if (!fill_tree_descriptor(&desc, oid)) {
 290                error(_("failed to find tree of %s"), oid_to_hex(oid));
 291                rollback_lock_file(&lock);
 292                free((void *)desc.buffer);
 293                return -1;
 294        }
 295
 296        if (unpack_trees(1, &desc, &unpack_tree_opts)) {
 297                rollback_lock_file(&lock);
 298                free((void *)desc.buffer);
 299                return -1;
 300        }
 301
 302        tree = parse_tree_indirect(oid);
 303        prime_cache_tree(the_repository->index, tree);
 304
 305        if (write_locked_index(the_repository->index, &lock, COMMIT_LOCK) < 0)
 306                ret = error(_("could not write index"));
 307        free((void *)desc.buffer);
 308
 309        if (ret)
 310                return ret;
 311
 312        reflog_action = getenv(GIT_REFLOG_ACTION_ENVIRONMENT);
 313        strbuf_addf(&msg, "%s: ", reflog_action ? reflog_action : "rebase");
 314        prefix_len = msg.len;
 315
 316        if (!get_oid("ORIG_HEAD", &oid_old_orig))
 317                old_orig = &oid_old_orig;
 318        if (!get_oid("HEAD", &oid_orig)) {
 319                orig = &oid_orig;
 320                strbuf_addstr(&msg, "updating ORIG_HEAD");
 321                update_ref(msg.buf, "ORIG_HEAD", orig, old_orig, 0,
 322                           UPDATE_REFS_MSG_ON_ERR);
 323        } else if (old_orig)
 324                delete_ref(NULL, "ORIG_HEAD", old_orig, 0);
 325        strbuf_setlen(&msg, prefix_len);
 326        strbuf_addstr(&msg, "updating HEAD");
 327        if (!switch_to_branch)
 328                ret = update_ref(msg.buf, "HEAD", oid, orig, REF_NO_DEREF,
 329                                 UPDATE_REFS_MSG_ON_ERR);
 330        else {
 331                ret = create_symref("HEAD", switch_to_branch, msg.buf);
 332                if (!ret)
 333                        ret = update_ref(msg.buf, "HEAD", oid, NULL, 0,
 334                                         UPDATE_REFS_MSG_ON_ERR);
 335        }
 336
 337        strbuf_release(&msg);
 338        return ret;
 339}
 340
 341static int rebase_config(const char *var, const char *value, void *data)
 342{
 343        struct rebase_options *opts = data;
 344
 345        if (!strcmp(var, "rebase.stat")) {
 346                if (git_config_bool(var, value))
 347                        opts->flags |= REBASE_DIFFSTAT;
 348                else
 349                        opts->flags &= !REBASE_DIFFSTAT;
 350                return 0;
 351        }
 352
 353        return git_default_config(var, value, data);
 354}
 355
 356/*
 357 * Determines whether the commits in from..to are linear, i.e. contain
 358 * no merge commits. This function *expects* `from` to be an ancestor of
 359 * `to`.
 360 */
 361static int is_linear_history(struct commit *from, struct commit *to)
 362{
 363        while (to && to != from) {
 364                parse_commit(to);
 365                if (!to->parents)
 366                        return 1;
 367                if (to->parents->next)
 368                        return 0;
 369                to = to->parents->item;
 370        }
 371        return 1;
 372}
 373
 374static int can_fast_forward(struct commit *onto, struct object_id *head_oid,
 375                            struct object_id *merge_base)
 376{
 377        struct commit *head = lookup_commit(the_repository, head_oid);
 378        struct commit_list *merge_bases;
 379        int res;
 380
 381        if (!head)
 382                return 0;
 383
 384        merge_bases = get_merge_bases(onto, head);
 385        if (merge_bases && !merge_bases->next) {
 386                oidcpy(merge_base, &merge_bases->item->object.oid);
 387                res = !oidcmp(merge_base, &onto->object.oid);
 388        } else {
 389                oidcpy(merge_base, &null_oid);
 390                res = 0;
 391        }
 392        free_commit_list(merge_bases);
 393        return res && is_linear_history(onto, head);
 394}
 395
 396int cmd_rebase(int argc, const char **argv, const char *prefix)
 397{
 398        struct rebase_options options = {
 399                .type = REBASE_UNSPECIFIED,
 400                .flags = REBASE_NO_QUIET,
 401                .git_am_opt = STRBUF_INIT,
 402        };
 403        const char *branch_name;
 404        int ret, flags, in_progress = 0;
 405        int ok_to_skip_pre_rebase = 0;
 406        struct strbuf msg = STRBUF_INIT;
 407        struct strbuf revisions = STRBUF_INIT;
 408        struct strbuf buf = STRBUF_INIT;
 409        struct object_id merge_base;
 410        struct option builtin_rebase_options[] = {
 411                OPT_STRING(0, "onto", &options.onto_name,
 412                           N_("revision"),
 413                           N_("rebase onto given branch instead of upstream")),
 414                OPT_BOOL(0, "no-verify", &ok_to_skip_pre_rebase,
 415                         N_("allow pre-rebase hook to run")),
 416                OPT_NEGBIT('q', "quiet", &options.flags,
 417                           N_("be quiet. implies --no-stat"),
 418                           REBASE_NO_QUIET| REBASE_VERBOSE | REBASE_DIFFSTAT),
 419                OPT_BIT('v', "verbose", &options.flags,
 420                        N_("display a diffstat of what changed upstream"),
 421                        REBASE_NO_QUIET | REBASE_VERBOSE | REBASE_DIFFSTAT),
 422                {OPTION_NEGBIT, 'n', "no-stat", &options.flags, NULL,
 423                        N_("do not show diffstat of what changed upstream"),
 424                        PARSE_OPT_NOARG, NULL, REBASE_DIFFSTAT },
 425                OPT_BIT('f', "force-rebase", &options.flags,
 426                        N_("cherry-pick all commits, even if unchanged"),
 427                        REBASE_FORCE),
 428                OPT_BIT(0, "no-ff", &options.flags,
 429                        N_("cherry-pick all commits, even if unchanged"),
 430                        REBASE_FORCE),
 431                OPT_END(),
 432        };
 433
 434        /*
 435         * NEEDSWORK: Once the builtin rebase has been tested enough
 436         * and git-legacy-rebase.sh is retired to contrib/, this preamble
 437         * can be removed.
 438         */
 439
 440        if (!use_builtin_rebase()) {
 441                const char *path = mkpath("%s/git-legacy-rebase",
 442                                          git_exec_path());
 443
 444                if (sane_execvp(path, (char **)argv) < 0)
 445                        die_errno(_("could not exec %s"), path);
 446                else
 447                        BUG("sane_execvp() returned???");
 448        }
 449
 450        if (argc == 2 && !strcmp(argv[1], "-h"))
 451                usage_with_options(builtin_rebase_usage,
 452                                   builtin_rebase_options);
 453
 454        prefix = setup_git_directory();
 455        trace_repo_setup(prefix);
 456        setup_work_tree();
 457
 458        git_config(rebase_config, &options);
 459
 460        if (is_directory(apply_dir())) {
 461                options.type = REBASE_AM;
 462                options.state_dir = apply_dir();
 463        } else if (is_directory(merge_dir())) {
 464                strbuf_reset(&buf);
 465                strbuf_addf(&buf, "%s/rewritten", merge_dir());
 466                if (is_directory(buf.buf)) {
 467                        options.type = REBASE_PRESERVE_MERGES;
 468                        options.flags |= REBASE_INTERACTIVE_EXPLICIT;
 469                } else {
 470                        strbuf_reset(&buf);
 471                        strbuf_addf(&buf, "%s/interactive", merge_dir());
 472                        if(file_exists(buf.buf)) {
 473                                options.type = REBASE_INTERACTIVE;
 474                                options.flags |= REBASE_INTERACTIVE_EXPLICIT;
 475                        } else
 476                                options.type = REBASE_MERGE;
 477                }
 478                options.state_dir = merge_dir();
 479        }
 480
 481        if (options.type != REBASE_UNSPECIFIED)
 482                in_progress = 1;
 483
 484        argc = parse_options(argc, argv, prefix,
 485                             builtin_rebase_options,
 486                             builtin_rebase_usage, 0);
 487
 488        if (argc > 2)
 489                usage_with_options(builtin_rebase_usage,
 490                                   builtin_rebase_options);
 491
 492        /* Make sure no rebase is in progress */
 493        if (in_progress) {
 494                const char *last_slash = strrchr(options.state_dir, '/');
 495                const char *state_dir_base =
 496                        last_slash ? last_slash + 1 : options.state_dir;
 497                const char *cmd_live_rebase =
 498                        "git rebase (--continue | --abort | --skip)";
 499                strbuf_reset(&buf);
 500                strbuf_addf(&buf, "rm -fr \"%s\"", options.state_dir);
 501                die(_("It seems that there is already a %s directory, and\n"
 502                      "I wonder if you are in the middle of another rebase.  "
 503                      "If that is the\n"
 504                      "case, please try\n\t%s\n"
 505                      "If that is not the case, please\n\t%s\n"
 506                      "and run me again.  I am stopping in case you still "
 507                      "have something\n"
 508                      "valuable there.\n"),
 509                    state_dir_base, cmd_live_rebase, buf.buf);
 510        }
 511
 512        if (!(options.flags & REBASE_NO_QUIET))
 513                strbuf_addstr(&options.git_am_opt, " -q");
 514
 515        switch (options.type) {
 516        case REBASE_MERGE:
 517        case REBASE_INTERACTIVE:
 518        case REBASE_PRESERVE_MERGES:
 519                options.state_dir = merge_dir();
 520                break;
 521        case REBASE_AM:
 522                options.state_dir = apply_dir();
 523                break;
 524        default:
 525                /* the default rebase backend is `--am` */
 526                options.type = REBASE_AM;
 527                options.state_dir = apply_dir();
 528                break;
 529        }
 530
 531        if (!options.root) {
 532                if (argc < 1)
 533                        die("TODO: handle @{upstream}");
 534                else {
 535                        options.upstream_name = argv[0];
 536                        argc--;
 537                        argv++;
 538                        if (!strcmp(options.upstream_name, "-"))
 539                                options.upstream_name = "@{-1}";
 540                }
 541                options.upstream = peel_committish(options.upstream_name);
 542                if (!options.upstream)
 543                        die(_("invalid upstream '%s'"), options.upstream_name);
 544                options.upstream_arg = options.upstream_name;
 545        } else
 546                die("TODO: upstream for --root");
 547
 548        /* Make sure the branch to rebase onto is valid. */
 549        if (!options.onto_name)
 550                options.onto_name = options.upstream_name;
 551        if (strstr(options.onto_name, "...")) {
 552                if (get_oid_mb(options.onto_name, &merge_base) < 0)
 553                        die(_("'%s': need exactly one merge base"),
 554                            options.onto_name);
 555                options.onto = lookup_commit_or_die(&merge_base,
 556                                                    options.onto_name);
 557        } else {
 558                options.onto = peel_committish(options.onto_name);
 559                if (!options.onto)
 560                        die(_("Does not point to a valid commit '%s'"),
 561                                options.onto_name);
 562        }
 563
 564        /*
 565         * If the branch to rebase is given, that is the branch we will rebase
 566         * branch_name -- branch/commit being rebased, or
 567         *                HEAD (already detached)
 568         * orig_head -- commit object name of tip of the branch before rebasing
 569         * head_name -- refs/heads/<that-branch> or NULL (detached HEAD)
 570         */
 571        if (argc == 1) {
 572                /* Is it "rebase other branchname" or "rebase other commit"? */
 573                branch_name = argv[0];
 574                options.switch_to = argv[0];
 575
 576                /* Is it a local branch? */
 577                strbuf_reset(&buf);
 578                strbuf_addf(&buf, "refs/heads/%s", branch_name);
 579                if (!read_ref(buf.buf, &options.orig_head))
 580                        options.head_name = xstrdup(buf.buf);
 581                /* If not is it a valid ref (branch or commit)? */
 582                else if (!get_oid(branch_name, &options.orig_head))
 583                        options.head_name = NULL;
 584                else
 585                        die(_("fatal: no such branch/commit '%s'"),
 586                            branch_name);
 587        } else if (argc == 0) {
 588                /* Do not need to switch branches, we are already on it. */
 589                options.head_name =
 590                        xstrdup_or_null(resolve_ref_unsafe("HEAD", 0, NULL,
 591                                         &flags));
 592                if (!options.head_name)
 593                        die(_("No such ref: %s"), "HEAD");
 594                if (flags & REF_ISSYMREF) {
 595                        if (!skip_prefix(options.head_name,
 596                                         "refs/heads/", &branch_name))
 597                                branch_name = options.head_name;
 598
 599                } else {
 600                        free(options.head_name);
 601                        options.head_name = NULL;
 602                        branch_name = "HEAD";
 603                }
 604                if (get_oid("HEAD", &options.orig_head))
 605                        die(_("Could not resolve HEAD to a revision"));
 606        } else
 607                BUG("unexpected number of arguments left to parse");
 608
 609        if (read_index(the_repository->index) < 0)
 610                die(_("could not read index"));
 611
 612        if (require_clean_work_tree("rebase",
 613                                    _("Please commit or stash them."), 1, 1)) {
 614                ret = 1;
 615                goto cleanup;
 616        }
 617
 618        /*
 619         * Now we are rebasing commits upstream..orig_head (or with --root,
 620         * everything leading up to orig_head) on top of onto.
 621         */
 622
 623        /*
 624         * Check if we are already based on onto with linear history,
 625         * but this should be done only when upstream and onto are the same
 626         * and if this is not an interactive rebase.
 627         */
 628        if (can_fast_forward(options.onto, &options.orig_head, &merge_base) &&
 629            !is_interactive(&options) && !options.restrict_revision &&
 630            !oidcmp(&options.upstream->object.oid, &options.onto->object.oid)) {
 631                int flag;
 632
 633                if (!(options.flags & REBASE_FORCE)) {
 634                        /* Lazily switch to the target branch if needed... */
 635                        if (options.switch_to) {
 636                                struct object_id oid;
 637
 638                                if (get_oid(options.switch_to, &oid) < 0) {
 639                                        ret = !!error(_("could not parse '%s'"),
 640                                                      options.switch_to);
 641                                        goto cleanup;
 642                                }
 643
 644                                strbuf_reset(&buf);
 645                                strbuf_addf(&buf, "rebase: checkout %s",
 646                                            options.switch_to);
 647                                if (reset_head(&oid, "checkout",
 648                                               options.head_name, 0) < 0) {
 649                                        ret = !!error(_("could not switch to "
 650                                                        "%s"),
 651                                                      options.switch_to);
 652                                        goto cleanup;
 653                                }
 654                        }
 655
 656                        if (!(options.flags & REBASE_NO_QUIET))
 657                                ; /* be quiet */
 658                        else if (!strcmp(branch_name, "HEAD") &&
 659                                 resolve_ref_unsafe("HEAD", 0, NULL, &flag))
 660                                puts(_("HEAD is up to date."));
 661                        else
 662                                printf(_("Current branch %s is up to date.\n"),
 663                                       branch_name);
 664                        ret = !!finish_rebase(&options);
 665                        goto cleanup;
 666                } else if (!(options.flags & REBASE_NO_QUIET))
 667                        ; /* be quiet */
 668                else if (!strcmp(branch_name, "HEAD") &&
 669                         resolve_ref_unsafe("HEAD", 0, NULL, &flag))
 670                        puts(_("HEAD is up to date, rebase forced."));
 671                else
 672                        printf(_("Current branch %s is up to date, rebase "
 673                                 "forced.\n"), branch_name);
 674        }
 675
 676        /* If a hook exists, give it a chance to interrupt*/
 677        if (!ok_to_skip_pre_rebase &&
 678            run_hook_le(NULL, "pre-rebase", options.upstream_arg,
 679                        argc ? argv[0] : NULL, NULL))
 680                die(_("The pre-rebase hook refused to rebase."));
 681
 682        if (options.flags & REBASE_DIFFSTAT) {
 683                struct diff_options opts;
 684
 685                if (options.flags & REBASE_VERBOSE)
 686                        printf(_("Changes from %s to %s:\n"),
 687                                oid_to_hex(&merge_base),
 688                                oid_to_hex(&options.onto->object.oid));
 689
 690                /* We want color (if set), but no pager */
 691                diff_setup(&opts);
 692                opts.stat_width = -1; /* use full terminal width */
 693                opts.stat_graph_width = -1; /* respect statGraphWidth config */
 694                opts.output_format |=
 695                        DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
 696                opts.detect_rename = DIFF_DETECT_RENAME;
 697                diff_setup_done(&opts);
 698                diff_tree_oid(&merge_base, &options.onto->object.oid,
 699                              "", &opts);
 700                diffcore_std(&opts);
 701                diff_flush(&opts);
 702        }
 703
 704        /* Detach HEAD and reset the tree */
 705        if (options.flags & REBASE_NO_QUIET)
 706                printf(_("First, rewinding head to replay your work on top of "
 707                         "it...\n"));
 708
 709        strbuf_addf(&msg, "rebase: checkout %s", options.onto_name);
 710        if (reset_head(&options.onto->object.oid, "checkout", NULL, 1))
 711                die(_("Could not detach HEAD"));
 712        strbuf_release(&msg);
 713
 714        strbuf_addf(&revisions, "%s..%s",
 715                    options.root ? oid_to_hex(&options.onto->object.oid) :
 716                    (options.restrict_revision ?
 717                     oid_to_hex(&options.restrict_revision->object.oid) :
 718                     oid_to_hex(&options.upstream->object.oid)),
 719                    oid_to_hex(&options.orig_head));
 720
 721        options.revisions = revisions.buf;
 722
 723        ret = !!run_specific_rebase(&options);
 724
 725cleanup:
 726        strbuf_release(&revisions);
 727        free(options.head_name);
 728        return ret;
 729}