builtin / revert.con commit Merge branch 'lt/default-abbrev' (da25842)
   1#include "cache.h"
   2#include "builtin.h"
   3#include "object.h"
   4#include "commit.h"
   5#include "tag.h"
   6#include "run-command.h"
   7#include "exec_cmd.h"
   8#include "utf8.h"
   9#include "parse-options.h"
  10#include "cache-tree.h"
  11#include "diff.h"
  12#include "revision.h"
  13#include "rerere.h"
  14#include "merge-recursive.h"
  15#include "refs.h"
  16
  17/*
  18 * This implements the builtins revert and cherry-pick.
  19 *
  20 * Copyright (c) 2007 Johannes E. Schindelin
  21 *
  22 * Based on git-revert.sh, which is
  23 *
  24 * Copyright (c) 2005 Linus Torvalds
  25 * Copyright (c) 2005 Junio C Hamano
  26 */
  27
  28static const char * const revert_usage[] = {
  29        "git revert [options] <commit-ish>",
  30        NULL
  31};
  32
  33static const char * const cherry_pick_usage[] = {
  34        "git cherry-pick [options] <commit-ish>",
  35        NULL
  36};
  37
  38static int edit, no_replay, no_commit, mainline, signoff, allow_ff;
  39static enum { REVERT, CHERRY_PICK } action;
  40static struct commit *commit;
  41static int commit_argc;
  42static const char **commit_argv;
  43static int allow_rerere_auto;
  44
  45static const char *me;
  46
  47/* Merge strategy. */
  48static const char *strategy;
  49static const char **xopts;
  50static size_t xopts_nr, xopts_alloc;
  51
  52#define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
  53
  54static char *get_encoding(const char *message);
  55
  56static const char * const *revert_or_cherry_pick_usage(void)
  57{
  58        return action == REVERT ? revert_usage : cherry_pick_usage;
  59}
  60
  61static int option_parse_x(const struct option *opt,
  62                          const char *arg, int unset)
  63{
  64        if (unset)
  65                return 0;
  66
  67        ALLOC_GROW(xopts, xopts_nr + 1, xopts_alloc);
  68        xopts[xopts_nr++] = xstrdup(arg);
  69        return 0;
  70}
  71
  72static void parse_args(int argc, const char **argv)
  73{
  74        const char * const * usage_str = revert_or_cherry_pick_usage();
  75        int noop;
  76        struct option options[] = {
  77                OPT_BOOLEAN('n', "no-commit", &no_commit, "don't automatically commit"),
  78                OPT_BOOLEAN('e', "edit", &edit, "edit the commit message"),
  79                OPT_BOOLEAN('r', NULL, &noop, "no-op (backward compatibility)"),
  80                OPT_BOOLEAN('s', "signoff", &signoff, "add Signed-off-by:"),
  81                OPT_INTEGER('m', "mainline", &mainline, "parent number"),
  82                OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
  83                OPT_STRING(0, "strategy", &strategy, "strategy", "merge strategy"),
  84                OPT_CALLBACK('X', "strategy-option", &xopts, "option",
  85                        "option for merge strategy", option_parse_x),
  86                OPT_END(),
  87                OPT_END(),
  88                OPT_END(),
  89        };
  90
  91        if (action == CHERRY_PICK) {
  92                struct option cp_extra[] = {
  93                        OPT_BOOLEAN('x', NULL, &no_replay, "append commit name"),
  94                        OPT_BOOLEAN(0, "ff", &allow_ff, "allow fast-forward"),
  95                        OPT_END(),
  96                };
  97                if (parse_options_concat(options, ARRAY_SIZE(options), cp_extra))
  98                        die("program error");
  99        }
 100
 101        commit_argc = parse_options(argc, argv, NULL, options, usage_str,
 102                                    PARSE_OPT_KEEP_ARGV0 |
 103                                    PARSE_OPT_KEEP_UNKNOWN);
 104        if (commit_argc < 2)
 105                usage_with_options(usage_str, options);
 106
 107        commit_argv = argv;
 108}
 109
 110struct commit_message {
 111        char *parent_label;
 112        const char *label;
 113        const char *subject;
 114        char *reencoded_message;
 115        const char *message;
 116};
 117
 118static int get_message(const char *raw_message, struct commit_message *out)
 119{
 120        const char *encoding;
 121        const char *abbrev, *subject;
 122        int abbrev_len, subject_len;
 123        char *q;
 124
 125        if (!raw_message)
 126                return -1;
 127        encoding = get_encoding(raw_message);
 128        if (!encoding)
 129                encoding = "UTF-8";
 130        if (!git_commit_encoding)
 131                git_commit_encoding = "UTF-8";
 132
 133        out->reencoded_message = NULL;
 134        out->message = raw_message;
 135        if (strcmp(encoding, git_commit_encoding))
 136                out->reencoded_message = reencode_string(raw_message,
 137                                        git_commit_encoding, encoding);
 138        if (out->reencoded_message)
 139                out->message = out->reencoded_message;
 140
 141        abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
 142        abbrev_len = strlen(abbrev);
 143
 144        subject_len = find_commit_subject(out->message, &subject);
 145
 146        out->parent_label = xmalloc(strlen("parent of ") + abbrev_len +
 147                              strlen("... ") + subject_len + 1);
 148        q = out->parent_label;
 149        q = mempcpy(q, "parent of ", strlen("parent of "));
 150        out->label = q;
 151        q = mempcpy(q, abbrev, abbrev_len);
 152        q = mempcpy(q, "... ", strlen("... "));
 153        out->subject = q;
 154        q = mempcpy(q, subject, subject_len);
 155        *q = '\0';
 156        return 0;
 157}
 158
 159static void free_message(struct commit_message *msg)
 160{
 161        free(msg->parent_label);
 162        free(msg->reencoded_message);
 163}
 164
 165static char *get_encoding(const char *message)
 166{
 167        const char *p = message, *eol;
 168
 169        if (!p)
 170                die ("Could not read commit message of %s",
 171                                sha1_to_hex(commit->object.sha1));
 172        while (*p && *p != '\n') {
 173                for (eol = p + 1; *eol && *eol != '\n'; eol++)
 174                        ; /* do nothing */
 175                if (!prefixcmp(p, "encoding ")) {
 176                        char *result = xmalloc(eol - 8 - p);
 177                        strlcpy(result, p + 9, eol - 8 - p);
 178                        return result;
 179                }
 180                p = eol;
 181                if (*p == '\n')
 182                        p++;
 183        }
 184        return NULL;
 185}
 186
 187static void add_message_to_msg(struct strbuf *msgbuf, const char *message)
 188{
 189        const char *p = message;
 190        while (*p && (*p != '\n' || p[1] != '\n'))
 191                p++;
 192
 193        if (!*p)
 194                strbuf_addstr(msgbuf, sha1_to_hex(commit->object.sha1));
 195
 196        p += 2;
 197        strbuf_addstr(msgbuf, p);
 198}
 199
 200static void write_cherry_pick_head(void)
 201{
 202        int fd;
 203        struct strbuf buf = STRBUF_INIT;
 204
 205        strbuf_addf(&buf, "%s\n", sha1_to_hex(commit->object.sha1));
 206
 207        fd = open(git_path("CHERRY_PICK_HEAD"), O_WRONLY | O_CREAT, 0666);
 208        if (fd < 0)
 209                die_errno("Could not open '%s' for writing",
 210                          git_path("CHERRY_PICK_HEAD"));
 211        if (write_in_full(fd, buf.buf, buf.len) != buf.len || close(fd))
 212                die_errno("Could not write to '%s'", git_path("CHERRY_PICK_HEAD"));
 213        strbuf_release(&buf);
 214}
 215
 216static void advise(const char *advice, ...)
 217{
 218        va_list params;
 219
 220        va_start(params, advice);
 221        vreportf("hint: ", advice, params);
 222        va_end(params);
 223}
 224
 225static void print_advice(void)
 226{
 227        char *msg = getenv("GIT_CHERRY_PICK_HELP");
 228
 229        if (msg) {
 230                fprintf(stderr, "%s\n", msg);
 231                /*
 232                 * A conflict has occured but the porcelain
 233                 * (typically rebase --interactive) wants to take care
 234                 * of the commit itself so remove CHERRY_PICK_HEAD
 235                 */
 236                unlink(git_path("CHERRY_PICK_HEAD"));
 237                return;
 238        }
 239
 240        advise("after resolving the conflicts, mark the corrected paths");
 241        advise("with 'git add <paths>' or 'git rm <paths>'");
 242        advise("and commit the result with 'git commit'");
 243}
 244
 245static void write_message(struct strbuf *msgbuf, const char *filename)
 246{
 247        static struct lock_file msg_file;
 248
 249        int msg_fd = hold_lock_file_for_update(&msg_file, filename,
 250                                               LOCK_DIE_ON_ERROR);
 251        if (write_in_full(msg_fd, msgbuf->buf, msgbuf->len) < 0)
 252                die_errno("Could not write to %s.", filename);
 253        strbuf_release(msgbuf);
 254        if (commit_lock_file(&msg_file) < 0)
 255                die("Error wrapping up %s", filename);
 256}
 257
 258static struct tree *empty_tree(void)
 259{
 260        struct tree *tree = xcalloc(1, sizeof(struct tree));
 261
 262        tree->object.parsed = 1;
 263        tree->object.type = OBJ_TREE;
 264        pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
 265        return tree;
 266}
 267
 268static NORETURN void die_dirty_index(const char *me)
 269{
 270        if (read_cache_unmerged()) {
 271                die_resolve_conflict(me);
 272        } else {
 273                if (advice_commit_before_merge)
 274                        die("Your local changes would be overwritten by %s.\n"
 275                            "Please, commit your changes or stash them to proceed.", me);
 276                else
 277                        die("Your local changes would be overwritten by %s.\n", me);
 278        }
 279}
 280
 281static int fast_forward_to(const unsigned char *to, const unsigned char *from)
 282{
 283        struct ref_lock *ref_lock;
 284
 285        read_cache();
 286        if (checkout_fast_forward(from, to))
 287                exit(1); /* the callee should have complained already */
 288        ref_lock = lock_any_ref_for_update("HEAD", from, 0);
 289        return write_ref_sha1(ref_lock, to, "cherry-pick");
 290}
 291
 292static int do_recursive_merge(struct commit *base, struct commit *next,
 293                              const char *base_label, const char *next_label,
 294                              unsigned char *head, struct strbuf *msgbuf)
 295{
 296        struct merge_options o;
 297        struct tree *result, *next_tree, *base_tree, *head_tree;
 298        int clean, index_fd;
 299        const char **xopt;
 300        static struct lock_file index_lock;
 301
 302        index_fd = hold_locked_index(&index_lock, 1);
 303
 304        read_cache();
 305
 306        init_merge_options(&o);
 307        o.ancestor = base ? base_label : "(empty tree)";
 308        o.branch1 = "HEAD";
 309        o.branch2 = next ? next_label : "(empty tree)";
 310
 311        head_tree = parse_tree_indirect(head);
 312        next_tree = next ? next->tree : empty_tree();
 313        base_tree = base ? base->tree : empty_tree();
 314
 315        for (xopt = xopts; xopt != xopts + xopts_nr; xopt++)
 316                parse_merge_opt(&o, *xopt);
 317
 318        clean = merge_trees(&o,
 319                            head_tree,
 320                            next_tree, base_tree, &result);
 321
 322        if (active_cache_changed &&
 323            (write_cache(index_fd, active_cache, active_nr) ||
 324             commit_locked_index(&index_lock)))
 325                die("%s: Unable to write new index file", me);
 326        rollback_lock_file(&index_lock);
 327
 328        if (!clean) {
 329                int i;
 330                strbuf_addstr(msgbuf, "\nConflicts:\n\n");
 331                for (i = 0; i < active_nr;) {
 332                        struct cache_entry *ce = active_cache[i++];
 333                        if (ce_stage(ce)) {
 334                                strbuf_addch(msgbuf, '\t');
 335                                strbuf_addstr(msgbuf, ce->name);
 336                                strbuf_addch(msgbuf, '\n');
 337                                while (i < active_nr && !strcmp(ce->name,
 338                                                active_cache[i]->name))
 339                                        i++;
 340                        }
 341                }
 342        }
 343
 344        return !clean;
 345}
 346
 347/*
 348 * If we are cherry-pick, and if the merge did not result in
 349 * hand-editing, we will hit this commit and inherit the original
 350 * author date and name.
 351 * If we are revert, or if our cherry-pick results in a hand merge,
 352 * we had better say that the current user is responsible for that.
 353 */
 354static int run_git_commit(const char *defmsg)
 355{
 356        /* 6 is max possible length of our args array including NULL */
 357        const char *args[6];
 358        int i = 0;
 359
 360        args[i++] = "commit";
 361        args[i++] = "-n";
 362        if (signoff)
 363                args[i++] = "-s";
 364        if (!edit) {
 365                args[i++] = "-F";
 366                args[i++] = defmsg;
 367        }
 368        args[i] = NULL;
 369
 370        return run_command_v_opt(args, RUN_GIT_CMD);
 371}
 372
 373static int do_pick_commit(void)
 374{
 375        unsigned char head[20];
 376        struct commit *base, *next, *parent;
 377        const char *base_label, *next_label;
 378        struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
 379        char *defmsg = NULL;
 380        struct strbuf msgbuf = STRBUF_INIT;
 381        int res;
 382
 383        if (no_commit) {
 384                /*
 385                 * We do not intend to commit immediately.  We just want to
 386                 * merge the differences in, so let's compute the tree
 387                 * that represents the "current" state for merge-recursive
 388                 * to work on.
 389                 */
 390                if (write_cache_as_tree(head, 0, NULL))
 391                        die ("Your index file is unmerged.");
 392        } else {
 393                if (get_sha1("HEAD", head))
 394                        die ("You do not have a valid HEAD");
 395                if (index_differs_from("HEAD", 0))
 396                        die_dirty_index(me);
 397        }
 398        discard_cache();
 399
 400        if (!commit->parents) {
 401                if (action == REVERT)
 402                        die ("Cannot revert a root commit");
 403                parent = NULL;
 404        }
 405        else if (commit->parents->next) {
 406                /* Reverting or cherry-picking a merge commit */
 407                int cnt;
 408                struct commit_list *p;
 409
 410                if (!mainline)
 411                        die("Commit %s is a merge but no -m option was given.",
 412                            sha1_to_hex(commit->object.sha1));
 413
 414                for (cnt = 1, p = commit->parents;
 415                     cnt != mainline && p;
 416                     cnt++)
 417                        p = p->next;
 418                if (cnt != mainline || !p)
 419                        die("Commit %s does not have parent %d",
 420                            sha1_to_hex(commit->object.sha1), mainline);
 421                parent = p->item;
 422        } else if (0 < mainline)
 423                die("Mainline was specified but commit %s is not a merge.",
 424                    sha1_to_hex(commit->object.sha1));
 425        else
 426                parent = commit->parents->item;
 427
 428        if (allow_ff && parent && !hashcmp(parent->object.sha1, head))
 429                return fast_forward_to(commit->object.sha1, head);
 430
 431        if (parent && parse_commit(parent) < 0)
 432                die("%s: cannot parse parent commit %s",
 433                    me, sha1_to_hex(parent->object.sha1));
 434
 435        if (get_message(commit->buffer, &msg) != 0)
 436                die("Cannot get commit message for %s",
 437                                sha1_to_hex(commit->object.sha1));
 438
 439        /*
 440         * "commit" is an existing commit.  We would want to apply
 441         * the difference it introduces since its first parent "prev"
 442         * on top of the current HEAD if we are cherry-pick.  Or the
 443         * reverse of it if we are revert.
 444         */
 445
 446        defmsg = git_pathdup("MERGE_MSG");
 447
 448        if (action == REVERT) {
 449                base = commit;
 450                base_label = msg.label;
 451                next = parent;
 452                next_label = msg.parent_label;
 453                strbuf_addstr(&msgbuf, "Revert \"");
 454                strbuf_addstr(&msgbuf, msg.subject);
 455                strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
 456                strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 457
 458                if (commit->parents->next) {
 459                        strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
 460                        strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
 461                }
 462                strbuf_addstr(&msgbuf, ".\n");
 463        } else {
 464                base = parent;
 465                base_label = msg.parent_label;
 466                next = commit;
 467                next_label = msg.label;
 468                add_message_to_msg(&msgbuf, msg.message);
 469                if (no_replay) {
 470                        strbuf_addstr(&msgbuf, "(cherry picked from commit ");
 471                        strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 472                        strbuf_addstr(&msgbuf, ")\n");
 473                }
 474                if (!no_commit)
 475                        write_cherry_pick_head();
 476        }
 477
 478        if (!strategy || !strcmp(strategy, "recursive") || action == REVERT) {
 479                res = do_recursive_merge(base, next, base_label, next_label,
 480                                         head, &msgbuf);
 481                write_message(&msgbuf, defmsg);
 482        } else {
 483                struct commit_list *common = NULL;
 484                struct commit_list *remotes = NULL;
 485
 486                write_message(&msgbuf, defmsg);
 487
 488                commit_list_insert(base, &common);
 489                commit_list_insert(next, &remotes);
 490                res = try_merge_command(strategy, xopts_nr, xopts, common,
 491                                        sha1_to_hex(head), remotes);
 492                free_commit_list(common);
 493                free_commit_list(remotes);
 494        }
 495
 496        if (res) {
 497                error("could not %s %s... %s",
 498                      action == REVERT ? "revert" : "apply",
 499                      find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV),
 500                      msg.subject);
 501                print_advice();
 502                rerere(allow_rerere_auto);
 503        } else {
 504                if (!no_commit)
 505                        res = run_git_commit(defmsg);
 506        }
 507
 508        free_message(&msg);
 509        free(defmsg);
 510
 511        return res;
 512}
 513
 514static void prepare_revs(struct rev_info *revs)
 515{
 516        int argc;
 517
 518        init_revisions(revs, NULL);
 519        revs->no_walk = 1;
 520        if (action != REVERT)
 521                revs->reverse = 1;
 522
 523        argc = setup_revisions(commit_argc, commit_argv, revs, NULL);
 524        if (argc > 1)
 525                usage(*revert_or_cherry_pick_usage());
 526
 527        if (prepare_revision_walk(revs))
 528                die("revision walk setup failed");
 529
 530        if (!revs->commits)
 531                die("empty commit set passed");
 532}
 533
 534static void read_and_refresh_cache(const char *me)
 535{
 536        static struct lock_file index_lock;
 537        int index_fd = hold_locked_index(&index_lock, 0);
 538        if (read_index_preload(&the_index, NULL) < 0)
 539                die("git %s: failed to read the index", me);
 540        refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
 541        if (the_index.cache_changed) {
 542                if (write_index(&the_index, index_fd) ||
 543                    commit_locked_index(&index_lock))
 544                        die("git %s: failed to refresh the index", me);
 545        }
 546        rollback_lock_file(&index_lock);
 547}
 548
 549static int revert_or_cherry_pick(int argc, const char **argv)
 550{
 551        struct rev_info revs;
 552
 553        git_config(git_default_config, NULL);
 554        me = action == REVERT ? "revert" : "cherry-pick";
 555        setenv(GIT_REFLOG_ACTION, me, 0);
 556        parse_args(argc, argv);
 557
 558        if (allow_ff) {
 559                if (signoff)
 560                        die("cherry-pick --ff cannot be used with --signoff");
 561                if (no_commit)
 562                        die("cherry-pick --ff cannot be used with --no-commit");
 563                if (no_replay)
 564                        die("cherry-pick --ff cannot be used with -x");
 565                if (edit)
 566                        die("cherry-pick --ff cannot be used with --edit");
 567        }
 568
 569        read_and_refresh_cache(me);
 570
 571        prepare_revs(&revs);
 572
 573        while ((commit = get_revision(&revs))) {
 574                int res = do_pick_commit();
 575                if (res)
 576                        return res;
 577        }
 578
 579        return 0;
 580}
 581
 582int cmd_revert(int argc, const char **argv, const char *prefix)
 583{
 584        if (isatty(0))
 585                edit = 1;
 586        action = REVERT;
 587        return revert_or_cherry_pick(argc, argv);
 588}
 589
 590int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
 591{
 592        action = CHERRY_PICK;
 593        return revert_or_cherry_pick(argc, argv);
 594}