02c23c957702206dcf9a503b7eea77406683e0b5
   1#include "cache.h"
   2#include "builtin.h"
   3#include "object.h"
   4#include "commit.h"
   5#include "tag.h"
   6#include "wt-status.h"
   7#include "run-command.h"
   8#include "exec_cmd.h"
   9#include "utf8.h"
  10#include "parse-options.h"
  11#include "cache-tree.h"
  12#include "diff.h"
  13#include "revision.h"
  14#include "rerere.h"
  15#include "merge-recursive.h"
  16#include "refs.h"
  17
  18/*
  19 * This implements the builtins revert and cherry-pick.
  20 *
  21 * Copyright (c) 2007 Johannes E. Schindelin
  22 *
  23 * Based on git-revert.sh, which is
  24 *
  25 * Copyright (c) 2005 Linus Torvalds
  26 * Copyright (c) 2005 Junio C Hamano
  27 */
  28
  29static const char * const revert_usage[] = {
  30        "git revert [options] <commit-ish>",
  31        NULL
  32};
  33
  34static const char * const cherry_pick_usage[] = {
  35        "git cherry-pick [options] <commit-ish>",
  36        NULL
  37};
  38
  39static int edit, no_replay, no_commit, mainline, signoff, allow_ff;
  40static enum { REVERT, CHERRY_PICK } action;
  41static struct commit *commit;
  42static int commit_argc;
  43static const char **commit_argv;
  44static int allow_rerere_auto;
  45
  46static const char *me;
  47
  48/* Merge strategy. */
  49static const char *strategy;
  50static const char **xopts;
  51static size_t xopts_nr, xopts_alloc;
  52
  53#define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
  54
  55static char *get_encoding(const char *message);
  56
  57static const char * const *revert_or_cherry_pick_usage(void)
  58{
  59        return action == REVERT ? revert_usage : cherry_pick_usage;
  60}
  61
  62static int option_parse_x(const struct option *opt,
  63                          const char *arg, int unset)
  64{
  65        if (unset)
  66                return 0;
  67
  68        ALLOC_GROW(xopts, xopts_nr + 1, xopts_alloc);
  69        xopts[xopts_nr++] = xstrdup(arg);
  70        return 0;
  71}
  72
  73static void parse_args(int argc, const char **argv)
  74{
  75        const char * const * usage_str = revert_or_cherry_pick_usage();
  76        int noop;
  77        struct option options[] = {
  78                OPT_BOOLEAN('n', "no-commit", &no_commit, "don't automatically commit"),
  79                OPT_BOOLEAN('e', "edit", &edit, "edit the commit message"),
  80                OPT_BOOLEAN('r', NULL, &noop, "no-op (backward compatibility)"),
  81                OPT_BOOLEAN('s', "signoff", &signoff, "add Signed-off-by:"),
  82                OPT_INTEGER('m', "mainline", &mainline, "parent number"),
  83                OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
  84                OPT_STRING(0, "strategy", &strategy, "strategy", "merge strategy"),
  85                OPT_CALLBACK('X', "strategy-option", &xopts, "option",
  86                        "option for merge strategy", option_parse_x),
  87                OPT_END(),
  88                OPT_END(),
  89                OPT_END(),
  90        };
  91
  92        if (action == CHERRY_PICK) {
  93                struct option cp_extra[] = {
  94                        OPT_BOOLEAN('x', NULL, &no_replay, "append commit name"),
  95                        OPT_BOOLEAN(0, "ff", &allow_ff, "allow fast-forward"),
  96                        OPT_END(),
  97                };
  98                if (parse_options_concat(options, ARRAY_SIZE(options), cp_extra))
  99                        die(_("program error"));
 100        }
 101
 102        commit_argc = parse_options(argc, argv, NULL, options, usage_str,
 103                                    PARSE_OPT_KEEP_ARGV0 |
 104                                    PARSE_OPT_KEEP_UNKNOWN);
 105        if (commit_argc < 2)
 106                usage_with_options(usage_str, options);
 107
 108        commit_argv = argv;
 109}
 110
 111struct commit_message {
 112        char *parent_label;
 113        const char *label;
 114        const char *subject;
 115        char *reencoded_message;
 116        const char *message;
 117};
 118
 119static int get_message(const char *raw_message, struct commit_message *out)
 120{
 121        const char *encoding;
 122        const char *abbrev, *subject;
 123        int abbrev_len, subject_len;
 124        char *q;
 125
 126        if (!raw_message)
 127                return -1;
 128        encoding = get_encoding(raw_message);
 129        if (!encoding)
 130                encoding = "UTF-8";
 131        if (!git_commit_encoding)
 132                git_commit_encoding = "UTF-8";
 133
 134        out->reencoded_message = NULL;
 135        out->message = raw_message;
 136        if (strcmp(encoding, git_commit_encoding))
 137                out->reencoded_message = reencode_string(raw_message,
 138                                        git_commit_encoding, encoding);
 139        if (out->reencoded_message)
 140                out->message = out->reencoded_message;
 141
 142        abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
 143        abbrev_len = strlen(abbrev);
 144
 145        subject_len = find_commit_subject(out->message, &subject);
 146
 147        out->parent_label = xmalloc(strlen("parent of ") + abbrev_len +
 148                              strlen("... ") + subject_len + 1);
 149        q = out->parent_label;
 150        q = mempcpy(q, "parent of ", strlen("parent of "));
 151        out->label = q;
 152        q = mempcpy(q, abbrev, abbrev_len);
 153        q = mempcpy(q, "... ", strlen("... "));
 154        out->subject = q;
 155        q = mempcpy(q, subject, subject_len);
 156        *q = '\0';
 157        return 0;
 158}
 159
 160static void free_message(struct commit_message *msg)
 161{
 162        free(msg->parent_label);
 163        free(msg->reencoded_message);
 164}
 165
 166static char *get_encoding(const char *message)
 167{
 168        const char *p = message, *eol;
 169
 170        if (!p)
 171                die (_("Could not read commit message of %s"),
 172                                sha1_to_hex(commit->object.sha1));
 173        while (*p && *p != '\n') {
 174                for (eol = p + 1; *eol && *eol != '\n'; eol++)
 175                        ; /* do nothing */
 176                if (!prefixcmp(p, "encoding ")) {
 177                        char *result = xmalloc(eol - 8 - p);
 178                        strlcpy(result, p + 9, eol - 8 - p);
 179                        return result;
 180                }
 181                p = eol;
 182                if (*p == '\n')
 183                        p++;
 184        }
 185        return NULL;
 186}
 187
 188static void add_message_to_msg(struct strbuf *msgbuf, const char *message)
 189{
 190        const char *p = message;
 191        while (*p && (*p != '\n' || p[1] != '\n'))
 192                p++;
 193
 194        if (!*p)
 195                strbuf_addstr(msgbuf, sha1_to_hex(commit->object.sha1));
 196
 197        p += 2;
 198        strbuf_addstr(msgbuf, p);
 199}
 200
 201static void set_author_ident_env(const char *message)
 202{
 203        const char *p = message;
 204        if (!p)
 205                die (_("Could not read commit message of %s"),
 206                                sha1_to_hex(commit->object.sha1));
 207        while (*p && *p != '\n') {
 208                const char *eol;
 209
 210                for (eol = p; *eol && *eol != '\n'; eol++)
 211                        ; /* do nothing */
 212                if (!prefixcmp(p, "author ")) {
 213                        char *line, *pend, *email, *timestamp;
 214
 215                        p += 7;
 216                        line = xmemdupz(p, eol - p);
 217                        email = strchr(line, '<');
 218                        if (!email)
 219                                die (_("Could not extract author email from %s"),
 220                                        sha1_to_hex(commit->object.sha1));
 221                        if (email == line)
 222                                pend = line;
 223                        else
 224                                for (pend = email; pend != line + 1 &&
 225                                                isspace(pend[-1]); pend--);
 226                                        ; /* do nothing */
 227                        *pend = '\0';
 228                        email++;
 229                        timestamp = strchr(email, '>');
 230                        if (!timestamp)
 231                                die (_("Could not extract author time from %s"),
 232                                        sha1_to_hex(commit->object.sha1));
 233                        *timestamp = '\0';
 234                        for (timestamp++; *timestamp && isspace(*timestamp);
 235                                        timestamp++)
 236                                ; /* do nothing */
 237                        setenv("GIT_AUTHOR_NAME", line, 1);
 238                        setenv("GIT_AUTHOR_EMAIL", email, 1);
 239                        setenv("GIT_AUTHOR_DATE", timestamp, 1);
 240                        free(line);
 241                        return;
 242                }
 243                p = eol;
 244                if (*p == '\n')
 245                        p++;
 246        }
 247        die (_("No author information found in %s"),
 248                        sha1_to_hex(commit->object.sha1));
 249}
 250
 251static void advise(const char *advice, ...)
 252{
 253        va_list params;
 254
 255        va_start(params, advice);
 256        vreportf("hint: ", advice, params);
 257        va_end(params);
 258}
 259
 260static void print_advice(void)
 261{
 262        char *msg = getenv("GIT_CHERRY_PICK_HELP");
 263
 264        if (msg) {
 265                fprintf(stderr, "%s\n", msg);
 266                return;
 267        }
 268
 269        advise("after resolving the conflicts, mark the corrected paths");
 270        advise("with 'git add <paths>' or 'git rm <paths>'");
 271
 272        if (action == CHERRY_PICK)
 273                advise("and commit the result with 'git commit -c %s'",
 274                       find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
 275}
 276
 277static void write_message(struct strbuf *msgbuf, const char *filename)
 278{
 279        static struct lock_file msg_file;
 280
 281        int msg_fd = hold_lock_file_for_update(&msg_file, filename,
 282                                               LOCK_DIE_ON_ERROR);
 283        if (write_in_full(msg_fd, msgbuf->buf, msgbuf->len) < 0)
 284                die_errno(_("Could not write to %s."), filename);
 285        strbuf_release(msgbuf);
 286        if (commit_lock_file(&msg_file) < 0)
 287                die(_("Error wrapping up %s"), filename);
 288}
 289
 290static struct tree *empty_tree(void)
 291{
 292        struct tree *tree = xcalloc(1, sizeof(struct tree));
 293
 294        tree->object.parsed = 1;
 295        tree->object.type = OBJ_TREE;
 296        pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
 297        return tree;
 298}
 299
 300static NORETURN void die_dirty_index(const char *me)
 301{
 302        if (read_cache_unmerged()) {
 303                die_resolve_conflict(me);
 304        } else {
 305                if (advice_commit_before_merge) {
 306                        if (action == REVERT)
 307                                die(_("Your local changes would be overwritten by revert.\n"
 308                                          "Please, commit your changes or stash them to proceed."));
 309                        else
 310                                die(_("Your local changes would be overwritten by cherry-pick.\n"
 311                                          "Please, commit your changes or stash them to proceed."));
 312                } else {
 313                        if (action == REVERT)
 314                                die(_("Your local changes would be overwritten by revert.\n"));
 315                        else
 316                                die(_("Your local changes would be overwritten by cherry-pick.\n"));
 317                }
 318        }
 319}
 320
 321static int fast_forward_to(const unsigned char *to, const unsigned char *from)
 322{
 323        struct ref_lock *ref_lock;
 324
 325        read_cache();
 326        if (checkout_fast_forward(from, to))
 327                exit(1); /* the callee should have complained already */
 328        ref_lock = lock_any_ref_for_update("HEAD", from, 0);
 329        return write_ref_sha1(ref_lock, to, "cherry-pick");
 330}
 331
 332static int do_recursive_merge(struct commit *base, struct commit *next,
 333                              const char *base_label, const char *next_label,
 334                              unsigned char *head, struct strbuf *msgbuf)
 335{
 336        struct merge_options o;
 337        struct tree *result, *next_tree, *base_tree, *head_tree;
 338        int clean, index_fd;
 339        const char **xopt;
 340        static struct lock_file index_lock;
 341
 342        index_fd = hold_locked_index(&index_lock, 1);
 343
 344        read_cache();
 345
 346        init_merge_options(&o);
 347        o.ancestor = base ? base_label : "(empty tree)";
 348        o.branch1 = "HEAD";
 349        o.branch2 = next ? next_label : "(empty tree)";
 350
 351        head_tree = parse_tree_indirect(head);
 352        next_tree = next ? next->tree : empty_tree();
 353        base_tree = base ? base->tree : empty_tree();
 354
 355        for (xopt = xopts; xopt != xopts + xopts_nr; xopt++)
 356                parse_merge_opt(&o, *xopt);
 357
 358        clean = merge_trees(&o,
 359                            head_tree,
 360                            next_tree, base_tree, &result);
 361
 362        if (active_cache_changed &&
 363            (write_cache(index_fd, active_cache, active_nr) ||
 364             commit_locked_index(&index_lock)))
 365                die("%s: Unable to write new index file", me);
 366        rollback_lock_file(&index_lock);
 367
 368        if (!clean) {
 369                int i;
 370                strbuf_addstr(msgbuf, "\nConflicts:\n\n");
 371                for (i = 0; i < active_nr;) {
 372                        struct cache_entry *ce = active_cache[i++];
 373                        if (ce_stage(ce)) {
 374                                strbuf_addch(msgbuf, '\t');
 375                                strbuf_addstr(msgbuf, ce->name);
 376                                strbuf_addch(msgbuf, '\n');
 377                                while (i < active_nr && !strcmp(ce->name,
 378                                                active_cache[i]->name))
 379                                        i++;
 380                        }
 381                }
 382        }
 383
 384        return !clean;
 385}
 386
 387/*
 388 * If we are cherry-pick, and if the merge did not result in
 389 * hand-editing, we will hit this commit and inherit the original
 390 * author date and name.
 391 * If we are revert, or if our cherry-pick results in a hand merge,
 392 * we had better say that the current user is responsible for that.
 393 */
 394static int run_git_commit(const char *defmsg)
 395{
 396        /* 6 is max possible length of our args array including NULL */
 397        const char *args[6];
 398        int i = 0;
 399
 400        args[i++] = "commit";
 401        args[i++] = "-n";
 402        if (signoff)
 403                args[i++] = "-s";
 404        if (!edit) {
 405                args[i++] = "-F";
 406                args[i++] = defmsg;
 407        }
 408        args[i] = NULL;
 409
 410        return run_command_v_opt(args, RUN_GIT_CMD);
 411}
 412
 413static int do_pick_commit(void)
 414{
 415        unsigned char head[20];
 416        struct commit *base, *next, *parent;
 417        const char *base_label, *next_label;
 418        struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
 419        char *defmsg = NULL;
 420        struct strbuf msgbuf = STRBUF_INIT;
 421        int res;
 422
 423        if (no_commit) {
 424                /*
 425                 * We do not intend to commit immediately.  We just want to
 426                 * merge the differences in, so let's compute the tree
 427                 * that represents the "current" state for merge-recursive
 428                 * to work on.
 429                 */
 430                if (write_cache_as_tree(head, 0, NULL))
 431                        die (_("Your index file is unmerged."));
 432        } else {
 433                if (get_sha1("HEAD", head))
 434                        die (_("You do not have a valid HEAD"));
 435                if (index_differs_from("HEAD", 0))
 436                        die_dirty_index(me);
 437        }
 438        discard_cache();
 439
 440        if (!commit->parents) {
 441                if (action == REVERT)
 442                        die (_("Cannot revert a root commit"));
 443                parent = NULL;
 444        }
 445        else if (commit->parents->next) {
 446                /* Reverting or cherry-picking a merge commit */
 447                int cnt;
 448                struct commit_list *p;
 449
 450                if (!mainline)
 451                        die(_("Commit %s is a merge but no -m option was given."),
 452                            sha1_to_hex(commit->object.sha1));
 453
 454                for (cnt = 1, p = commit->parents;
 455                     cnt != mainline && p;
 456                     cnt++)
 457                        p = p->next;
 458                if (cnt != mainline || !p)
 459                        die(_("Commit %s does not have parent %d"),
 460                            sha1_to_hex(commit->object.sha1), mainline);
 461                parent = p->item;
 462        } else if (0 < mainline)
 463                die(_("Mainline was specified but commit %s is not a merge."),
 464                    sha1_to_hex(commit->object.sha1));
 465        else
 466                parent = commit->parents->item;
 467
 468        if (allow_ff && parent && !hashcmp(parent->object.sha1, head))
 469                return fast_forward_to(commit->object.sha1, head);
 470
 471        if (parent && parse_commit(parent) < 0)
 472                die("%s: cannot parse parent commit %s",
 473                    me, sha1_to_hex(parent->object.sha1));
 474
 475        if (get_message(commit->buffer, &msg) != 0)
 476                die(_("Cannot get commit message for %s"),
 477                                sha1_to_hex(commit->object.sha1));
 478
 479        /*
 480         * "commit" is an existing commit.  We would want to apply
 481         * the difference it introduces since its first parent "prev"
 482         * on top of the current HEAD if we are cherry-pick.  Or the
 483         * reverse of it if we are revert.
 484         */
 485
 486        defmsg = git_pathdup("MERGE_MSG");
 487
 488        if (action == REVERT) {
 489                base = commit;
 490                base_label = msg.label;
 491                next = parent;
 492                next_label = msg.parent_label;
 493                strbuf_addstr(&msgbuf, "Revert \"");
 494                strbuf_addstr(&msgbuf, msg.subject);
 495                strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
 496                strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 497
 498                if (commit->parents->next) {
 499                        strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
 500                        strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
 501                }
 502                strbuf_addstr(&msgbuf, ".\n");
 503        } else {
 504                base = parent;
 505                base_label = msg.parent_label;
 506                next = commit;
 507                next_label = msg.label;
 508                set_author_ident_env(msg.message);
 509                add_message_to_msg(&msgbuf, msg.message);
 510                if (no_replay) {
 511                        strbuf_addstr(&msgbuf, "(cherry picked from commit ");
 512                        strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 513                        strbuf_addstr(&msgbuf, ")\n");
 514                }
 515        }
 516
 517        if (!strategy || !strcmp(strategy, "recursive") || action == REVERT) {
 518                res = do_recursive_merge(base, next, base_label, next_label,
 519                                         head, &msgbuf);
 520                write_message(&msgbuf, defmsg);
 521        } else {
 522                struct commit_list *common = NULL;
 523                struct commit_list *remotes = NULL;
 524
 525                write_message(&msgbuf, defmsg);
 526
 527                commit_list_insert(base, &common);
 528                commit_list_insert(next, &remotes);
 529                res = try_merge_command(strategy, xopts_nr, xopts, common,
 530                                        sha1_to_hex(head), remotes);
 531                free_commit_list(common);
 532                free_commit_list(remotes);
 533        }
 534
 535        if (res) {
 536                error("could not %s %s... %s",
 537                      action == REVERT ? "revert" : "apply",
 538                      find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV),
 539                      msg.subject);
 540                print_advice();
 541                rerere(allow_rerere_auto);
 542        } else {
 543                if (!no_commit)
 544                        res = run_git_commit(defmsg);
 545        }
 546
 547        free_message(&msg);
 548        free(defmsg);
 549
 550        return res;
 551}
 552
 553static void prepare_revs(struct rev_info *revs)
 554{
 555        int argc;
 556
 557        init_revisions(revs, NULL);
 558        revs->no_walk = 1;
 559        if (action != REVERT)
 560                revs->reverse = 1;
 561
 562        argc = setup_revisions(commit_argc, commit_argv, revs, NULL);
 563        if (argc > 1)
 564                usage(*revert_or_cherry_pick_usage());
 565
 566        if (prepare_revision_walk(revs))
 567                die(_("revision walk setup failed"));
 568
 569        if (!revs->commits)
 570                die(_("empty commit set passed"));
 571}
 572
 573static void read_and_refresh_cache(const char *me)
 574{
 575        static struct lock_file index_lock;
 576        int index_fd = hold_locked_index(&index_lock, 0);
 577        if (read_index_preload(&the_index, NULL) < 0)
 578                die(_("git %s: failed to read the index"), me);
 579        refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
 580        if (the_index.cache_changed) {
 581                if (write_index(&the_index, index_fd) ||
 582                    commit_locked_index(&index_lock))
 583                        die(_("git %s: failed to refresh the index"), me);
 584        }
 585        rollback_lock_file(&index_lock);
 586}
 587
 588static int revert_or_cherry_pick(int argc, const char **argv)
 589{
 590        struct rev_info revs;
 591
 592        git_config(git_default_config, NULL);
 593        me = action == REVERT ? "revert" : "cherry-pick";
 594        setenv(GIT_REFLOG_ACTION, me, 0);
 595        parse_args(argc, argv);
 596
 597        if (allow_ff) {
 598                if (signoff)
 599                        die(_("cherry-pick --ff cannot be used with --signoff"));
 600                if (no_commit)
 601                        die(_("cherry-pick --ff cannot be used with --no-commit"));
 602                if (no_replay)
 603                        die(_("cherry-pick --ff cannot be used with -x"));
 604                if (edit)
 605                        die(_("cherry-pick --ff cannot be used with --edit"));
 606        }
 607
 608        read_and_refresh_cache(me);
 609
 610        prepare_revs(&revs);
 611
 612        while ((commit = get_revision(&revs))) {
 613                int res = do_pick_commit();
 614                if (res)
 615                        return res;
 616        }
 617
 618        return 0;
 619}
 620
 621int cmd_revert(int argc, const char **argv, const char *prefix)
 622{
 623        if (isatty(0))
 624                edit = 1;
 625        action = REVERT;
 626        return revert_or_cherry_pick(argc, argv);
 627}
 628
 629int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
 630{
 631        action = CHERRY_PICK;
 632        return revert_or_cherry_pick(argc, argv);
 633}