ad612497a2aba1039ab19976a147738dec100a8a
   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
  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;
  39static enum { REVERT, CHERRY_PICK } action;
  40static struct commit *commit;
  41static const char *commit_name;
  42static int allow_rerere_auto;
  43
  44static const char *me;
  45
  46#define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
  47
  48static void parse_args(int argc, const char **argv)
  49{
  50        const char * const * usage_str =
  51                action == REVERT ?  revert_usage : cherry_pick_usage;
  52        unsigned char sha1[20];
  53        int noop;
  54        struct option options[] = {
  55                OPT_BOOLEAN('n', "no-commit", &no_commit, "don't automatically commit"),
  56                OPT_BOOLEAN('e', "edit", &edit, "edit the commit message"),
  57                OPT_BOOLEAN('x', NULL, &no_replay, "append commit name when cherry-picking"),
  58                OPT_BOOLEAN('r', NULL, &noop, "no-op (backward compatibility)"),
  59                OPT_BOOLEAN('s', "signoff", &signoff, "add Signed-off-by:"),
  60                OPT_INTEGER('m', "mainline", &mainline, "parent number"),
  61                OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
  62                OPT_END(),
  63        };
  64
  65        if (parse_options(argc, argv, NULL, options, usage_str, 0) != 1)
  66                usage_with_options(usage_str, options);
  67
  68        commit_name = argv[0];
  69        if (get_sha1(commit_name, sha1))
  70                die ("Cannot find '%s'", commit_name);
  71        commit = lookup_commit_reference(sha1);
  72        if (!commit)
  73                exit(1);
  74}
  75
  76static char *get_oneline(const char *message)
  77{
  78        char *result;
  79        const char *p = message, *abbrev, *eol;
  80        int abbrev_len, oneline_len;
  81
  82        if (!p)
  83                die ("Could not read commit message of %s",
  84                                sha1_to_hex(commit->object.sha1));
  85        while (*p && (*p != '\n' || p[1] != '\n'))
  86                p++;
  87
  88        if (*p) {
  89                p += 2;
  90                for (eol = p + 1; *eol && *eol != '\n'; eol++)
  91                        ; /* do nothing */
  92        } else
  93                eol = p;
  94        abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
  95        abbrev_len = strlen(abbrev);
  96        oneline_len = eol - p;
  97        result = xmalloc(abbrev_len + 5 + oneline_len);
  98        memcpy(result, abbrev, abbrev_len);
  99        memcpy(result + abbrev_len, "... ", 4);
 100        memcpy(result + abbrev_len + 4, p, oneline_len);
 101        result[abbrev_len + 4 + oneline_len] = '\0';
 102        return result;
 103}
 104
 105static char *get_encoding(const char *message)
 106{
 107        const char *p = message, *eol;
 108
 109        if (!p)
 110                die ("Could not read commit message of %s",
 111                                sha1_to_hex(commit->object.sha1));
 112        while (*p && *p != '\n') {
 113                for (eol = p + 1; *eol && *eol != '\n'; eol++)
 114                        ; /* do nothing */
 115                if (!prefixcmp(p, "encoding ")) {
 116                        char *result = xmalloc(eol - 8 - p);
 117                        strlcpy(result, p + 9, eol - 8 - p);
 118                        return result;
 119                }
 120                p = eol;
 121                if (*p == '\n')
 122                        p++;
 123        }
 124        return NULL;
 125}
 126
 127static struct lock_file msg_file;
 128static int msg_fd;
 129
 130static void add_to_msg(const char *string)
 131{
 132        int len = strlen(string);
 133        if (write_in_full(msg_fd, string, len) < 0)
 134                die_errno ("Could not write to MERGE_MSG");
 135}
 136
 137static void add_message_to_msg(const char *message)
 138{
 139        const char *p = message;
 140        while (*p && (*p != '\n' || p[1] != '\n'))
 141                p++;
 142
 143        if (!*p)
 144                add_to_msg(sha1_to_hex(commit->object.sha1));
 145
 146        p += 2;
 147        add_to_msg(p);
 148        return;
 149}
 150
 151static void set_author_ident_env(const char *message)
 152{
 153        const char *p = message;
 154        if (!p)
 155                die ("Could not read commit message of %s",
 156                                sha1_to_hex(commit->object.sha1));
 157        while (*p && *p != '\n') {
 158                const char *eol;
 159
 160                for (eol = p; *eol && *eol != '\n'; eol++)
 161                        ; /* do nothing */
 162                if (!prefixcmp(p, "author ")) {
 163                        char *line, *pend, *email, *timestamp;
 164
 165                        p += 7;
 166                        line = xmemdupz(p, eol - p);
 167                        email = strchr(line, '<');
 168                        if (!email)
 169                                die ("Could not extract author email from %s",
 170                                        sha1_to_hex(commit->object.sha1));
 171                        if (email == line)
 172                                pend = line;
 173                        else
 174                                for (pend = email; pend != line + 1 &&
 175                                                isspace(pend[-1]); pend--);
 176                                        ; /* do nothing */
 177                        *pend = '\0';
 178                        email++;
 179                        timestamp = strchr(email, '>');
 180                        if (!timestamp)
 181                                die ("Could not extract author time from %s",
 182                                        sha1_to_hex(commit->object.sha1));
 183                        *timestamp = '\0';
 184                        for (timestamp++; *timestamp && isspace(*timestamp);
 185                                        timestamp++)
 186                                ; /* do nothing */
 187                        setenv("GIT_AUTHOR_NAME", line, 1);
 188                        setenv("GIT_AUTHOR_EMAIL", email, 1);
 189                        setenv("GIT_AUTHOR_DATE", timestamp, 1);
 190                        free(line);
 191                        return;
 192                }
 193                p = eol;
 194                if (*p == '\n')
 195                        p++;
 196        }
 197        die ("No author information found in %s",
 198                        sha1_to_hex(commit->object.sha1));
 199}
 200
 201static char *help_msg(const char *name)
 202{
 203        struct strbuf helpbuf = STRBUF_INIT;
 204        char *msg = getenv("GIT_CHERRY_PICK_HELP");
 205
 206        if (msg)
 207                return msg;
 208
 209        strbuf_addstr(&helpbuf, "  After resolving the conflicts,\n"
 210                "mark the corrected paths with 'git add <paths>' or 'git rm <paths>'\n"
 211                "and commit the result.");
 212
 213        if (action == CHERRY_PICK) {
 214                strbuf_addf(&helpbuf,
 215                        "  When committing, use the option '-c %s'\n"
 216                        "to retain authorship and message.",
 217                        name);
 218        }
 219        return strbuf_detach(&helpbuf, NULL);
 220}
 221
 222static struct tree *empty_tree(void)
 223{
 224        struct tree *tree = xcalloc(1, sizeof(struct tree));
 225
 226        tree->object.parsed = 1;
 227        tree->object.type = OBJ_TREE;
 228        pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
 229        return tree;
 230}
 231
 232static NORETURN void die_dirty_index(const char *me)
 233{
 234        if (read_cache_unmerged()) {
 235                die_resolve_conflict(me);
 236        } else {
 237                if (advice_commit_before_merge)
 238                        die("Your local changes would be overwritten by %s.\n"
 239                            "Please, commit your changes or stash them to proceed.", me);
 240                else
 241                        die("Your local changes would be overwritten by %s.\n", me);
 242        }
 243}
 244
 245static int revert_or_cherry_pick(int argc, const char **argv)
 246{
 247        unsigned char head[20];
 248        struct commit *base, *next, *parent;
 249        int i, index_fd, clean;
 250        char *oneline, *reencoded_message = NULL;
 251        const char *message, *encoding;
 252        char *defmsg = git_pathdup("MERGE_MSG");
 253        struct merge_options o;
 254        struct tree *result, *next_tree, *base_tree, *head_tree;
 255        static struct lock_file index_lock;
 256
 257        git_config(git_default_config, NULL);
 258        me = action == REVERT ? "revert" : "cherry-pick";
 259        setenv(GIT_REFLOG_ACTION, me, 0);
 260        parse_args(argc, argv);
 261
 262        /* this is copied from the shell script, but it's never triggered... */
 263        if (action == REVERT && !no_replay)
 264                die("revert is incompatible with replay");
 265
 266        if (read_cache() < 0)
 267                die("git %s: failed to read the index", me);
 268        if (no_commit) {
 269                /*
 270                 * We do not intend to commit immediately.  We just want to
 271                 * merge the differences in, so let's compute the tree
 272                 * that represents the "current" state for merge-recursive
 273                 * to work on.
 274                 */
 275                if (write_cache_as_tree(head, 0, NULL))
 276                        die ("Your index file is unmerged.");
 277        } else {
 278                if (get_sha1("HEAD", head))
 279                        die ("You do not have a valid HEAD");
 280                if (index_differs_from("HEAD", 0))
 281                        die_dirty_index(me);
 282        }
 283        discard_cache();
 284
 285        index_fd = hold_locked_index(&index_lock, 1);
 286
 287        if (!commit->parents) {
 288                if (action == REVERT)
 289                        die ("Cannot revert a root commit");
 290                parent = NULL;
 291        }
 292        else if (commit->parents->next) {
 293                /* Reverting or cherry-picking a merge commit */
 294                int cnt;
 295                struct commit_list *p;
 296
 297                if (!mainline)
 298                        die("Commit %s is a merge but no -m option was given.",
 299                            sha1_to_hex(commit->object.sha1));
 300
 301                for (cnt = 1, p = commit->parents;
 302                     cnt != mainline && p;
 303                     cnt++)
 304                        p = p->next;
 305                if (cnt != mainline || !p)
 306                        die("Commit %s does not have parent %d",
 307                            sha1_to_hex(commit->object.sha1), mainline);
 308                parent = p->item;
 309        } else if (0 < mainline)
 310                die("Mainline was specified but commit %s is not a merge.",
 311                    sha1_to_hex(commit->object.sha1));
 312        else
 313                parent = commit->parents->item;
 314
 315        if (!(message = commit->buffer))
 316                die ("Cannot get commit message for %s",
 317                                sha1_to_hex(commit->object.sha1));
 318
 319        if (parent && parse_commit(parent) < 0)
 320                die("%s: cannot parse parent commit %s",
 321                    me, sha1_to_hex(parent->object.sha1));
 322
 323        /*
 324         * "commit" is an existing commit.  We would want to apply
 325         * the difference it introduces since its first parent "prev"
 326         * on top of the current HEAD if we are cherry-pick.  Or the
 327         * reverse of it if we are revert.
 328         */
 329
 330        msg_fd = hold_lock_file_for_update(&msg_file, defmsg,
 331                                           LOCK_DIE_ON_ERROR);
 332
 333        encoding = get_encoding(message);
 334        if (!encoding)
 335                encoding = "UTF-8";
 336        if (!git_commit_encoding)
 337                git_commit_encoding = "UTF-8";
 338        if ((reencoded_message = reencode_string(message,
 339                                        git_commit_encoding, encoding)))
 340                message = reencoded_message;
 341
 342        oneline = get_oneline(message);
 343
 344        if (action == REVERT) {
 345                char *oneline_body = strchr(oneline, ' ');
 346
 347                base = commit;
 348                next = parent;
 349                add_to_msg("Revert \"");
 350                add_to_msg(oneline_body + 1);
 351                add_to_msg("\"\n\nThis reverts commit ");
 352                add_to_msg(sha1_to_hex(commit->object.sha1));
 353
 354                if (commit->parents->next) {
 355                        add_to_msg(", reversing\nchanges made to ");
 356                        add_to_msg(sha1_to_hex(parent->object.sha1));
 357                }
 358                add_to_msg(".\n");
 359        } else {
 360                base = parent;
 361                next = commit;
 362                set_author_ident_env(message);
 363                add_message_to_msg(message);
 364                if (no_replay) {
 365                        add_to_msg("(cherry picked from commit ");
 366                        add_to_msg(sha1_to_hex(commit->object.sha1));
 367                        add_to_msg(")\n");
 368                }
 369        }
 370
 371        read_cache();
 372        init_merge_options(&o);
 373        o.branch1 = "HEAD";
 374        o.branch2 = oneline;
 375
 376        head_tree = parse_tree_indirect(head);
 377        next_tree = next ? next->tree : empty_tree();
 378        base_tree = base ? base->tree : empty_tree();
 379
 380        clean = merge_trees(&o,
 381                            head_tree,
 382                            next_tree, base_tree, &result);
 383
 384        if (active_cache_changed &&
 385            (write_cache(index_fd, active_cache, active_nr) ||
 386             commit_locked_index(&index_lock)))
 387                die("%s: Unable to write new index file", me);
 388        rollback_lock_file(&index_lock);
 389
 390        if (!clean) {
 391                add_to_msg("\nConflicts:\n\n");
 392                for (i = 0; i < active_nr;) {
 393                        struct cache_entry *ce = active_cache[i++];
 394                        if (ce_stage(ce)) {
 395                                add_to_msg("\t");
 396                                add_to_msg(ce->name);
 397                                add_to_msg("\n");
 398                                while (i < active_nr && !strcmp(ce->name,
 399                                                active_cache[i]->name))
 400                                        i++;
 401                        }
 402                }
 403                if (commit_lock_file(&msg_file) < 0)
 404                        die ("Error wrapping up %s", defmsg);
 405                fprintf(stderr, "Automatic %s failed.%s\n",
 406                        me, help_msg(commit_name));
 407                rerere(allow_rerere_auto);
 408                exit(1);
 409        }
 410        if (commit_lock_file(&msg_file) < 0)
 411                die ("Error wrapping up %s", defmsg);
 412        fprintf(stderr, "Finished one %s.\n", me);
 413
 414        /*
 415         *
 416         * If we are cherry-pick, and if the merge did not result in
 417         * hand-editing, we will hit this commit and inherit the original
 418         * author date and name.
 419         * If we are revert, or if our cherry-pick results in a hand merge,
 420         * we had better say that the current user is responsible for that.
 421         */
 422
 423        if (!no_commit) {
 424                /* 6 is max possible length of our args array including NULL */
 425                const char *args[6];
 426                int i = 0;
 427                args[i++] = "commit";
 428                args[i++] = "-n";
 429                if (signoff)
 430                        args[i++] = "-s";
 431                if (!edit) {
 432                        args[i++] = "-F";
 433                        args[i++] = defmsg;
 434                }
 435                args[i] = NULL;
 436                return execv_git_cmd(args);
 437        }
 438        free(reencoded_message);
 439        free(defmsg);
 440
 441        return 0;
 442}
 443
 444int cmd_revert(int argc, const char **argv, const char *prefix)
 445{
 446        if (isatty(0))
 447                edit = 1;
 448        no_replay = 1;
 449        action = REVERT;
 450        return revert_or_cherry_pick(argc, argv);
 451}
 452
 453int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
 454{
 455        no_replay = 0;
 456        action = CHERRY_PICK;
 457        return revert_or_cherry_pick(argc, argv);
 458}