builtin/commit.c

   1 /*
   2  * Builtin "git commit"
   3  *
   4  * Copyright (c) 2007 Kristian Høgsberg <krh@redhat.com>
   5  * Based on git-commit.sh by Junio C Hamano and Linus Torvalds
   6  */
   7
   8 #include "cache.h"
   9 #include "cache-tree.h"
  10 #include "color.h"
  11 #include "dir.h"
  12 #include "builtin.h"
  13 #include "diff.h"
  14 #include "diffcore.h"
  15 #include "commit.h"
  16 #include "revision.h"
  17 #include "wt-status.h"
  18 #include "run-command.h"
  19 #include "refs.h"
  20 #include "log-tree.h"
  21 #include "strbuf.h"
  22 #include "utf8.h"
  23 #include "parse-options.h"
  24 #include "string-list.h"
  25 #include "rerere.h"
  26 #include "unpack-trees.h"
  27 #include "quote.h"
  28
  29 static const char * const builtin_commit_usage[] = {
  30         "git commit [options] [--] <filepattern>...",
  31         NULL
  32 };
  33
  34 static const char * const builtin_status_usage[] = {
  35         "git status [options] [--] <filepattern>...",
  36         NULL
  37 };
  38
  39 static const char implicit_ident_advice[] =
  40 "Your name and email address were configured automatically based\n"
  41 "on your username and hostname. Please check that they are accurate.\n"
  42 "You can suppress this message by setting them explicitly:\n"
  43 "\n"
  44 "    git config --global user.name \"Your Name\"\n"
  45 "    git config --global user.email you@example.com\n"
  46 "\n"
  47 "If the identity used for this commit is wrong, you can fix it with:\n"
  48 "\n"
  49 "    git commit --amend --author='Your Name <you@example.com>'\n";
  50
  51 static const char empty_amend_advice[] =
  52 "You asked to amend the most recent commit, but doing so would make\n"
  53 "it empty. You can repeat your command with --allow-empty, or you can\n"
  54 "remove the commit entirely with \"git reset HEAD^\".\n";
  55
  56 static unsigned char head_sha1[20];
  57
  58 static char *use_message_buffer;
  59 static const char commit_editmsg[] = "COMMIT_EDITMSG";
  60 static struct lock_file index_lock; /* real index */
  61 static struct lock_file false_lock; /* used only for partial commits */
  62 static enum {
  63         COMMIT_AS_IS = 1,
  64         COMMIT_NORMAL,
  65         COMMIT_PARTIAL
  66 } commit_style;
  67
  68 static const char *logfile, *force_author;
  69 static const char *template_file;
  70 static char *edit_message, *use_message;
  71 static char *author_name, *author_email, *author_date;
  72 static int all, edit_flag, also, interactive, only, amend, signoff;
  73 static int quiet, verbose, no_verify, allow_empty, dry_run, renew_authorship;
  74 static int no_post_rewrite, allow_empty_message;
  75 static char *untracked_files_arg, *force_date;
  76 /*
  77  * The default commit message cleanup mode will remove the lines
  78  * beginning with # (shell comments) and leading and trailing
  79  * whitespaces (empty lines or containing only whitespaces)
  80  * if editor is used, and only the whitespaces if the message
  81  * is specified explicitly.
  82  */
  83 static enum {
  84         CLEANUP_SPACE,
  85         CLEANUP_NONE,
  86         CLEANUP_ALL
  87 } cleanup_mode;
  88 static char *cleanup_arg;
  89
  90 static int use_editor = 1, initial_commit, in_merge, include_status = 1;
  91 static int show_ignored_in_status;
  92 static const char *only_include_assumed;
  93 static struct strbuf message;
  94
  95 static int null_termination;
  96 static enum {
  97         STATUS_FORMAT_LONG,
  98         STATUS_FORMAT_SHORT,
  99         STATUS_FORMAT_PORCELAIN
 100 } status_format = STATUS_FORMAT_LONG;
 101 static int status_show_branch;
 102
 103 static int opt_parse_m(const struct option *opt, const char *arg, int unset)
 104 {
 105         struct strbuf *buf = opt->value;
 106         if (unset)
 107                 strbuf_setlen(buf, 0);
 108         else {
 109                 strbuf_addstr(buf, arg);
 110                 strbuf_addstr(buf, "\n\n");
 111         }
 112         return 0;
 113 }
 114
 115 static struct option builtin_commit_options[] = {
 116         OPT__QUIET(&quiet),
 117         OPT__VERBOSE(&verbose),
 118
 119         OPT_GROUP("Commit message options"),
 120         OPT_FILENAME('F', "file", &logfile, "read log from file"),
 121         OPT_STRING(0, "author", &force_author, "AUTHOR", "override author for commit"),
 122         OPT_STRING(0, "date", &force_date, "DATE", "override date for commit"),
 123         OPT_CALLBACK('m', "message", &message, "MESSAGE", "specify commit message", opt_parse_m),
 124         OPT_STRING('c', "reedit-message", &edit_message, "COMMIT", "reuse and edit message from specified commit"),
 125         OPT_STRING('C', "reuse-message", &use_message, "COMMIT", "reuse message from specified commit"),
 126         OPT_BOOLEAN(0, "reset-author", &renew_authorship, "the commit is authored by me now (used with -C-c/--amend)"),
 127         OPT_BOOLEAN('s', "signoff", &signoff, "add Signed-off-by:"),
 128         OPT_FILENAME('t', "template", &template_file, "use specified template file"),
 129         OPT_BOOLEAN('e', "edit", &edit_flag, "force edit of commit"),
 130         OPT_STRING(0, "cleanup", &cleanup_arg, "default", "how to strip spaces and #comments from message"),
 131         OPT_BOOLEAN(0, "status", &include_status, "include status in commit message template"),
 132         /* end commit message options */
 133
 134         OPT_GROUP("Commit contents options"),
 135         OPT_BOOLEAN('a', "all", &all, "commit all changed files"),
 136         OPT_BOOLEAN('i', "include", &also, "add specified files to index for commit"),
 137         OPT_BOOLEAN(0, "interactive", &interactive, "interactively add files"),
 138         OPT_BOOLEAN('o', "only", &only, "commit only specified files"),
 139         OPT_BOOLEAN('n', "no-verify", &no_verify, "bypass pre-commit hook"),
 140         OPT_BOOLEAN(0, "dry-run", &dry_run, "show what would be committed"),
 141         OPT_SET_INT(0, "short", &status_format, "show status concisely",
 142                     STATUS_FORMAT_SHORT),
 143         OPT_BOOLEAN(0, "branch", &status_show_branch, "show branch information"),
 144         OPT_SET_INT(0, "porcelain", &status_format,
 145                     "show porcelain output format", STATUS_FORMAT_PORCELAIN),
 146         OPT_BOOLEAN('z', "null", &null_termination,
 147                     "terminate entries with NUL"),
 148         OPT_BOOLEAN(0, "amend", &amend, "amend previous commit"),
 149         OPT_BOOLEAN(0, "no-post-rewrite", &no_post_rewrite, "bypass post-rewrite hook"),
 150         { OPTION_STRING, 'u', "untracked-files", &untracked_files_arg, "mode", "show untracked files, optional modes: all, normal, no. (Default: all)", PARSE_OPT_OPTARG, NULL, (intptr_t)"all" },
 151         /* end commit contents options */
 152
 153         { OPTION_BOOLEAN, 0, "allow-empty", &allow_empty, NULL,
 154           "ok to record an empty change",
 155           PARSE_OPT_NOARG | PARSE_OPT_HIDDEN },
 156         { OPTION_BOOLEAN, 0, "allow-empty-message", &allow_empty_message, NULL,
 157           "ok to record a change with an empty message",
 158           PARSE_OPT_NOARG | PARSE_OPT_HIDDEN },
 159
 160         OPT_END()
 161 };
 162
 163 static void rollback_index_files(void)
 164 {
 165         switch (commit_style) {
 166         case COMMIT_AS_IS:
 167                 break; /* nothing to do */
 168         case COMMIT_NORMAL:
 169                 rollback_lock_file(&index_lock);
 170                 break;
 171         case COMMIT_PARTIAL:
 172                 rollback_lock_file(&index_lock);
 173                 rollback_lock_file(&false_lock);
 174                 break;
 175         }
 176 }
 177
 178 static int commit_index_files(void)
 179 {
 180         int err = 0;
 181
 182         switch (commit_style) {
 183         case COMMIT_AS_IS:
 184                 break; /* nothing to do */
 185         case COMMIT_NORMAL:
 186                 err = commit_lock_file(&index_lock);
 187                 break;
 188         case COMMIT_PARTIAL:
 189                 err = commit_lock_file(&index_lock);
 190                 rollback_lock_file(&false_lock);
 191                 break;
 192         }
 193
 194         return err;
 195 }
 196
 197 /*
 198  * Take a union of paths in the index and the named tree (typically, "HEAD"),
 199  * and return the paths that match the given pattern in list.
 200  */
 201 static int list_paths(struct string_list *list, const char *with_tree,
 202                       const char *prefix, const char **pattern)
 203 {
 204         int i;
 205         char *m;
 206
 207         for (i = 0; pattern[i]; i++)
 208                 ;
 209         m = xcalloc(1, i);
 210
 211         if (with_tree)
 212                 overlay_tree_on_cache(with_tree, prefix);
 213
 214         for (i = 0; i < active_nr; i++) {
 215                 struct cache_entry *ce = active_cache[i];
 216                 struct string_list_item *item;
 217
 218                 if (ce->ce_flags & CE_UPDATE)
 219                         continue;
 220                 if (!match_pathspec(pattern, ce->name, ce_namelen(ce), 0, m))
 221                         continue;
 222                 item = string_list_insert(ce->name, list);
 223                 if (ce_skip_worktree(ce))
 224                         item->util = item; /* better a valid pointer than a fake one */
 225         }
 226
 227         return report_path_error(m, pattern, prefix ? strlen(prefix) : 0);
 228 }
 229
 230 static void add_remove_files(struct string_list *list)
 231 {
 232         int i;
 233         for (i = 0; i < list->nr; i++) {
 234                 struct stat st;
 235                 struct string_list_item *p = &(list->items[i]);
 236
 237                 /* p->util is skip-worktree */
 238                 if (p->util)
 239                         continue;
 240
 241                 if (!lstat(p->string, &st)) {
 242                         if (add_to_cache(p->string, &st, 0))
 243                                 die("updating files failed");
 244                 } else
 245                         remove_file_from_cache(p->string);
 246         }
 247 }
 248
 249 static void create_base_index(void)
 250 {
 251         struct tree *tree;
 252         struct unpack_trees_options opts;
 253         struct tree_desc t;
 254
 255         if (initial_commit) {
 256                 discard_cache();
 257                 return;
 258         }
 259
 260         memset(&opts, 0, sizeof(opts));
 261         opts.head_idx = 1;
 262         opts.index_only = 1;
 263         opts.merge = 1;
 264         opts.src_index = &the_index;
 265         opts.dst_index = &the_index;
 266
 267         opts.fn = oneway_merge;
 268         tree = parse_tree_indirect(head_sha1);
 269         if (!tree)
 270                 die("failed to unpack HEAD tree object");
 271         parse_tree(tree);
 272         init_tree_desc(&t, tree->buffer, tree->size);
 273         if (unpack_trees(1, &t, &opts))
 274                 exit(128); /* We've already reported the error, finish dying */
 275 }
 276
 277 static void refresh_cache_or_die(int refresh_flags)
 278 {
 279         /*
 280          * refresh_flags contains REFRESH_QUIET, so the only errors
 281          * are for unmerged entries.
 282          */
 283         if (refresh_cache(refresh_flags | REFRESH_IN_PORCELAIN))
 284                 die_resolve_conflict("commit");
 285 }
 286
 287 static char *prepare_index(int argc, const char **argv, const char *prefix, int is_status)
 288 {
 289         int fd;
 290         struct string_list partial;
 291         const char **pathspec = NULL;
 292         int refresh_flags = REFRESH_QUIET;
 293
 294         if (is_status)
 295                 refresh_flags |= REFRESH_UNMERGED;
 296         if (interactive) {
 297                 if (interactive_add(argc, argv, prefix) != 0)
 298                         die("interactive add failed");
 299                 if (read_cache_preload(NULL) < 0)
 300                         die("index file corrupt");
 301                 commit_style = COMMIT_AS_IS;
 302                 return get_index_file();
 303         }
 304
 305         if (*argv)
 306                 pathspec = get_pathspec(prefix, argv);
 307
 308         if (read_cache_preload(pathspec) < 0)
 309                 die("index file corrupt");
 310
 311         /*
 312          * Non partial, non as-is commit.
 313          *
 314          * (1) get the real index;
 315          * (2) update the_index as necessary;
 316          * (3) write the_index out to the real index (still locked);
 317          * (4) return the name of the locked index file.
 318          *
 319          * The caller should run hooks on the locked real index, and
 320          * (A) if all goes well, commit the real index;
 321          * (B) on failure, rollback the real index.
 322          */
 323         if (all || (also && pathspec && *pathspec)) {
 324                 fd = hold_locked_index(&index_lock, 1);
 325                 add_files_to_cache(also ? prefix : NULL, pathspec, 0);
 326                 refresh_cache_or_die(refresh_flags);
 327                 if (write_cache(fd, active_cache, active_nr) ||
 328                     close_lock_file(&index_lock))
 329                         die("unable to write new_index file");
 330                 commit_style = COMMIT_NORMAL;
 331                 return index_lock.filename;
 332         }
 333
 334         /*
 335          * As-is commit.
 336          *
 337          * (1) return the name of the real index file.
 338          *
 339          * The caller should run hooks on the real index,
 340          * and create commit from the_index.
 341          * We still need to refresh the index here.
 342          */
 343         if (!pathspec || !*pathspec) {
 344                 fd = hold_locked_index(&index_lock, 1);
 345                 refresh_cache_or_die(refresh_flags);
 346                 if (write_cache(fd, active_cache, active_nr) ||
 347                     commit_locked_index(&index_lock))
 348                         die("unable to write new_index file");
 349                 commit_style = COMMIT_AS_IS;
 350                 return get_index_file();
 351         }
 352
 353         /*
 354          * A partial commit.
 355          *
 356          * (0) find the set of affected paths;
 357          * (1) get lock on the real index file;
 358          * (2) update the_index with the given paths;
 359          * (3) write the_index out to the real index (still locked);
 360          * (4) get lock on the false index file;
 361          * (5) reset the_index from HEAD;
 362          * (6) update the_index the same way as (2);
 363          * (7) write the_index out to the false index file;
 364          * (8) return the name of the false index file (still locked);
 365          *
 366          * The caller should run hooks on the locked false index, and
 367          * create commit from it.  Then
 368          * (A) if all goes well, commit the real index;
 369          * (B) on failure, rollback the real index;
 370          * In either case, rollback the false index.
 371          */
 372         commit_style = COMMIT_PARTIAL;
 373
 374         if (in_merge)
 375                 die("cannot do a partial commit during a merge.");
 376
 377         memset(&partial, 0, sizeof(partial));
 378         partial.strdup_strings = 1;
 379         if (list_paths(&partial, initial_commit ? NULL : "HEAD", prefix, pathspec))
 380                 exit(1);
 381
 382         discard_cache();
 383         if (read_cache() < 0)
 384                 die("cannot read the index");
 385
 386         fd = hold_locked_index(&index_lock, 1);
 387         add_remove_files(&partial);
 388         refresh_cache(REFRESH_QUIET);
 389         if (write_cache(fd, active_cache, active_nr) ||
 390             close_lock_file(&index_lock))
 391                 die("unable to write new_index file");
 392
 393         fd = hold_lock_file_for_update(&false_lock,
 394                                        git_path("next-index-%"PRIuMAX,
 395                                                 (uintmax_t) getpid()),
 396                                        LOCK_DIE_ON_ERROR);
 397
 398         create_base_index();
 399         add_remove_files(&partial);
 400         refresh_cache(REFRESH_QUIET);
 401
 402         if (write_cache(fd, active_cache, active_nr) ||
 403             close_lock_file(&false_lock))
 404                 die("unable to write temporary index file");
 405
 406         discard_cache();
 407         read_cache_from(false_lock.filename);
 408
 409         return false_lock.filename;
 410 }
 411
 412 static int run_status(FILE *fp, const char *index_file, const char *prefix, int nowarn,
 413                       struct wt_status *s)
 414 {
 415         unsigned char sha1[20];
 416
 417         if (s->relative_paths)
 418                 s->prefix = prefix;
 419
 420         if (amend) {
 421                 s->amend = 1;
 422                 s->reference = "HEAD^1";
 423         }
 424         s->verbose = verbose;
 425         s->index_file = index_file;
 426         s->fp = fp;
 427         s->nowarn = nowarn;
 428         s->is_initial = get_sha1(s->reference, sha1) ? 1 : 0;
 429
 430         wt_status_collect(s);
 431
 432         switch (status_format) {
 433         case STATUS_FORMAT_SHORT:
 434                 wt_shortstatus_print(s, null_termination, status_show_branch);
 435                 break;
 436         case STATUS_FORMAT_PORCELAIN:
 437                 wt_porcelain_print(s, null_termination);
 438                 break;
 439         case STATUS_FORMAT_LONG:
 440                 wt_status_print(s);
 441                 break;
 442         }
 443
 444         return s->commitable;
 445 }
 446
 447 static int is_a_merge(const unsigned char *sha1)
 448 {
 449         struct commit *commit = lookup_commit(sha1);
 450         if (!commit || parse_commit(commit))
 451                 die("could not parse HEAD commit");
 452         return !!(commit->parents && commit->parents->next);
 453 }
 454
 455 static const char sign_off_header[] = "Signed-off-by: ";
 456
 457 static void determine_author_info(void)
 458 {
 459         char *name, *email, *date;
 460
 461         name = getenv("GIT_AUTHOR_NAME");
 462         email = getenv("GIT_AUTHOR_EMAIL");
 463         date = getenv("GIT_AUTHOR_DATE");
 464
 465         if (use_message && !renew_authorship) {
 466                 const char *a, *lb, *rb, *eol;
 467
 468                 a = strstr(use_message_buffer, "\nauthor ");
 469                 if (!a)
 470                         die("invalid commit: %s", use_message);
 471
 472                 lb = strchrnul(a + strlen("\nauthor "), '<');
 473                 rb = strchrnul(lb, '>');
 474                 eol = strchrnul(rb, '\n');
 475                 if (!*lb || !*rb || !*eol)
 476                         die("invalid commit: %s", use_message);
 477
 478                 if (lb == a + strlen("\nauthor "))
 479                         /* \nauthor <foo@example.com> */
 480                         name = xcalloc(1, 1);
 481                 else
 482                         name = xmemdupz(a + strlen("\nauthor "),
 483                                         (lb - strlen(" ") -
 484                                          (a + strlen("\nauthor "))));
 485                 email = xmemdupz(lb + strlen("<"), rb - (lb + strlen("<")));
 486                 date = xmemdupz(rb + strlen("> "), eol - (rb + strlen("> ")));
 487         }
 488
 489         if (force_author) {
 490                 const char *lb = strstr(force_author, " <");
 491                 const char *rb = strchr(force_author, '>');
 492
 493                 if (!lb || !rb)
 494                         die("malformed --author parameter");
 495                 name = xstrndup(force_author, lb - force_author);
 496                 email = xstrndup(lb + 2, rb - (lb + 2));
 497         }
 498
 499         if (force_date)
 500                 date = force_date;
 501
 502         author_name = name;
 503         author_email = email;
 504         author_date = date;
 505 }
 506
 507 static int ends_rfc2822_footer(struct strbuf *sb)
 508 {
 509         int ch;
 510         int hit = 0;
 511         int i, j, k;
 512         int len = sb->len;
 513         int first = 1;
 514         const char *buf = sb->buf;
 515
 516         for (i = len - 1; i > 0; i--) {
 517                 if (hit && buf[i] == '\n')
 518                         break;
 519                 hit = (buf[i] == '\n');
 520         }
 521
 522         while (i < len - 1 && buf[i] == '\n')
 523                 i++;
 524
 525         for (; i < len; i = k) {
 526                 for (k = i; k < len && buf[k] != '\n'; k++)
 527                         ; /* do nothing */
 528                 k++;
 529
 530                 if ((buf[k] == ' ' || buf[k] == '\t') && !first)
 531                         continue;
 532
 533                 first = 0;
 534
 535                 for (j = 0; i + j < len; j++) {
 536                         ch = buf[i + j];
 537                         if (ch == ':')
 538                                 break;
 539                         if (isalnum(ch) ||
 540                             (ch == '-'))
 541                                 continue;
 542                         return 0;
 543                 }
 544         }
 545         return 1;
 546 }
 547
 548 static int prepare_to_commit(const char *index_file, const char *prefix,
 549                              struct wt_status *s)
 550 {
 551         struct stat statbuf;
 552         int commitable, saved_color_setting;
 553         struct strbuf sb = STRBUF_INIT;
 554         char *buffer;
 555         FILE *fp;
 556         const char *hook_arg1 = NULL;
 557         const char *hook_arg2 = NULL;
 558         int ident_shown = 0;
 559
 560         if (!no_verify && run_hook(index_file, "pre-commit", NULL))
 561                 return 0;
 562
 563         if (message.len) {
 564                 strbuf_addbuf(&sb, &message);
 565                 hook_arg1 = "message";
 566         } else if (logfile && !strcmp(logfile, "-")) {
 567                 if (isatty(0))
 568                         fprintf(stderr, "(reading log message from standard input)\n");
 569                 if (strbuf_read(&sb, 0, 0) < 0)
 570                         die_errno("could not read log from standard input");
 571                 hook_arg1 = "message";
 572         } else if (logfile) {
 573                 if (strbuf_read_file(&sb, logfile, 0) < 0)
 574                         die_errno("could not read log file '%s'",
 575                                   logfile);
 576                 hook_arg1 = "message";
 577         } else if (use_message) {
 578                 buffer = strstr(use_message_buffer, "\n\n");
 579                 if (!buffer || buffer[2] == '\0')
 580                         die("commit has empty message");
 581                 strbuf_add(&sb, buffer + 2, strlen(buffer + 2));
 582                 hook_arg1 = "commit";
 583                 hook_arg2 = use_message;
 584         } else if (!stat(git_path("MERGE_MSG"), &statbuf)) {
 585                 if (strbuf_read_file(&sb, git_path("MERGE_MSG"), 0) < 0)
 586                         die_errno("could not read MERGE_MSG");
 587                 hook_arg1 = "merge";
 588         } else if (!stat(git_path("SQUASH_MSG"), &statbuf)) {
 589                 if (strbuf_read_file(&sb, git_path("SQUASH_MSG"), 0) < 0)
 590                         die_errno("could not read SQUASH_MSG");
 591                 hook_arg1 = "squash";
 592         } else if (template_file && !stat(template_file, &statbuf)) {
 593                 if (strbuf_read_file(&sb, template_file, 0) < 0)
 594                         die_errno("could not read '%s'", template_file);
 595                 hook_arg1 = "template";
 596         }
 597
 598         /*
 599          * This final case does not modify the template message,
 600          * it just sets the argument to the prepare-commit-msg hook.
 601          */
 602         else if (in_merge)
 603                 hook_arg1 = "merge";
 604
 605         fp = fopen(git_path(commit_editmsg), "w");
 606         if (fp == NULL)
 607                 die_errno("could not open '%s'", git_path(commit_editmsg));
 608
 609         if (cleanup_mode != CLEANUP_NONE)
 610                 stripspace(&sb, 0);
 611
 612         if (signoff) {
 613                 struct strbuf sob = STRBUF_INIT;
 614                 int i;
 615
 616                 strbuf_addstr(&sob, sign_off_header);
 617                 strbuf_addstr(&sob, fmt_name(getenv("GIT_COMMITTER_NAME"),
 618                                              getenv("GIT_COMMITTER_EMAIL")));
 619                 strbuf_addch(&sob, '\n');
 620                 for (i = sb.len - 1; i > 0 && sb.buf[i - 1] != '\n'; i--)
 621                         ; /* do nothing */
 622                 if (prefixcmp(sb.buf + i, sob.buf)) {
 623                         if (!i || !ends_rfc2822_footer(&sb))
 624                                 strbuf_addch(&sb, '\n');
 625                         strbuf_addbuf(&sb, &sob);
 626                 }
 627                 strbuf_release(&sob);
 628         }
 629
 630         if (fwrite(sb.buf, 1, sb.len, fp) < sb.len)
 631                 die_errno("could not write commit template");
 632
 633         strbuf_release(&sb);
 634
 635         determine_author_info();
 636
 637         /* This checks if committer ident is explicitly given */
 638         git_committer_info(0);
 639         if (use_editor && include_status) {
 640                 char *author_ident;
 641                 const char *committer_ident;
 642
 643                 if (in_merge)
 644                         fprintf(fp,
 645                                 "#\n"
 646                                 "# It looks like you may be committing a MERGE.\n"
 647                                 "# If this is not correct, please remove the file\n"
 648                                 "#      %s\n"
 649                                 "# and try again.\n"
 650                                 "#\n",
 651                                 git_path("MERGE_HEAD"));
 652
 653                 fprintf(fp,
 654                         "\n"
 655                         "# Please enter the commit message for your changes.");
 656                 if (cleanup_mode == CLEANUP_ALL)
 657                         fprintf(fp,
 658                                 " Lines starting\n"
 659                                 "# with '#' will be ignored, and an empty"
 660                                 " message aborts the commit.\n");
 661                 else /* CLEANUP_SPACE, that is. */
 662                         fprintf(fp,
 663                                 " Lines starting\n"
 664                                 "# with '#' will be kept; you may remove them"
 665                                 " yourself if you want to.\n"
 666                                 "# An empty message aborts the commit.\n");
 667                 if (only_include_assumed)
 668                         fprintf(fp, "# %s\n", only_include_assumed);
 669
 670                 author_ident = xstrdup(fmt_name(author_name, author_email));
 671                 committer_ident = fmt_name(getenv("GIT_COMMITTER_NAME"),
 672                                            getenv("GIT_COMMITTER_EMAIL"));
 673                 if (strcmp(author_ident, committer_ident))
 674                         fprintf(fp,
 675                                 "%s"
 676                                 "# Author:    %s\n",
 677                                 ident_shown++ ? "" : "#\n",
 678                                 author_ident);
 679                 free(author_ident);
 680
 681                 if (!user_ident_sufficiently_given())
 682                         fprintf(fp,
 683                                 "%s"
 684                                 "# Committer: %s\n",
 685                                 ident_shown++ ? "" : "#\n",
 686                                 committer_ident);
 687
 688                 if (ident_shown)
 689                         fprintf(fp, "#\n");
 690
 691                 saved_color_setting = s->use_color;
 692                 s->use_color = 0;
 693                 commitable = run_status(fp, index_file, prefix, 1, s);
 694                 s->use_color = saved_color_setting;
 695         } else {
 696                 unsigned char sha1[20];
 697                 const char *parent = "HEAD";
 698
 699                 if (!active_nr && read_cache() < 0)
 700                         die("Cannot read index");
 701
 702                 if (amend)
 703                         parent = "HEAD^1";
 704
 705                 if (get_sha1(parent, sha1))
 706                         commitable = !!active_nr;
 707                 else
 708                         commitable = index_differs_from(parent, 0);
 709         }
 710
 711         fclose(fp);
 712
 713         if (!commitable && !in_merge && !allow_empty &&
 714             !(amend && is_a_merge(head_sha1))) {
 715                 run_status(stdout, index_file, prefix, 0, s);
 716                 if (amend)
 717                         fputs(empty_amend_advice, stderr);
 718                 return 0;
 719         }
 720
 721         /*
 722          * Re-read the index as pre-commit hook could have updated it,
 723          * and write it out as a tree.  We must do this before we invoke
 724          * the editor and after we invoke run_status above.
 725          */
 726         discard_cache();
 727         read_cache_from(index_file);
 728         if (!active_cache_tree)
 729                 active_cache_tree = cache_tree();
 730         if (cache_tree_update(active_cache_tree,
 731                               active_cache, active_nr, 0, 0) < 0) {
 732                 error("Error building trees");
 733                 return 0;
 734         }
 735
 736         if (run_hook(index_file, "prepare-commit-msg",
 737                      git_path(commit_editmsg), hook_arg1, hook_arg2, NULL))
 738                 return 0;
 739
 740         if (use_editor) {
 741                 char index[PATH_MAX];
 742                 const char *env[2] = { NULL };
 743                 env[0] =  index;
 744                 snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
 745                 if (launch_editor(git_path(commit_editmsg), NULL, env)) {
 746                         fprintf(stderr,
 747                         "Please supply the message using either -m or -F option.\n");
 748                         exit(1);
 749                 }
 750         }
 751
 752         if (!no_verify &&
 753             run_hook(index_file, "commit-msg", git_path(commit_editmsg), NULL)) {
 754                 return 0;
 755         }
 756
 757         return 1;
 758 }
 759
 760 /*
 761  * Find out if the message in the strbuf contains only whitespace and
 762  * Signed-off-by lines.
 763  */
 764 static int message_is_empty(struct strbuf *sb)
 765 {
 766         struct strbuf tmpl = STRBUF_INIT;
 767         const char *nl;
 768         int eol, i, start = 0;
 769
 770         if (cleanup_mode == CLEANUP_NONE && sb->len)
 771                 return 0;
 772
 773         /* See if the template is just a prefix of the message. */
 774         if (template_file && strbuf_read_file(&tmpl, template_file, 0) > 0) {
 775                 stripspace(&tmpl, cleanup_mode == CLEANUP_ALL);
 776                 if (start + tmpl.len <= sb->len &&
 777                     memcmp(tmpl.buf, sb->buf + start, tmpl.len) == 0)
 778                         start += tmpl.len;
 779         }
 780         strbuf_release(&tmpl);
 781
 782         /* Check if the rest is just whitespace and Signed-of-by's. */
 783         for (i = start; i < sb->len; i++) {
 784                 nl = memchr(sb->buf + i, '\n', sb->len - i);
 785                 if (nl)
 786                         eol = nl - sb->buf;
 787                 else
 788                         eol = sb->len;
 789
 790                 if (strlen(sign_off_header) <= eol - i &&
 791                     !prefixcmp(sb->buf + i, sign_off_header)) {
 792                         i = eol;
 793                         continue;
 794                 }
 795                 while (i < eol)
 796                         if (!isspace(sb->buf[i++]))
 797                                 return 0;
 798         }
 799
 800         return 1;
 801 }
 802
 803 static const char *find_author_by_nickname(const char *name)
 804 {
 805         struct rev_info revs;
 806         struct commit *commit;
 807         struct strbuf buf = STRBUF_INIT;
 808         const char *av[20];
 809         int ac = 0;
 810
 811         init_revisions(&revs, NULL);
 812         strbuf_addf(&buf, "--author=%s", name);
 813         av[++ac] = "--all";
 814         av[++ac] = "-i";
 815         av[++ac] = buf.buf;
 816         av[++ac] = NULL;
 817         setup_revisions(ac, av, &revs, NULL);
 818         prepare_revision_walk(&revs);
 819         commit = get_revision(&revs);
 820         if (commit) {
 821                 struct pretty_print_context ctx = {0};
 822                 ctx.date_mode = DATE_NORMAL;
 823                 strbuf_release(&buf);
 824                 format_commit_message(commit, "%an <%ae>", &buf, &ctx);
 825                 return strbuf_detach(&buf, NULL);
 826         }
 827         die("No existing author found with '%s'", name);
 828 }
 829
 830
 831 static void handle_untracked_files_arg(struct wt_status *s)
 832 {
 833         if (!untracked_files_arg)
 834                 ; /* default already initialized */
 835         else if (!strcmp(untracked_files_arg, "no"))
 836                 s->show_untracked_files = SHOW_NO_UNTRACKED_FILES;
 837         else if (!strcmp(untracked_files_arg, "normal"))
 838                 s->show_untracked_files = SHOW_NORMAL_UNTRACKED_FILES;
 839         else if (!strcmp(untracked_files_arg, "all"))
 840                 s->show_untracked_files = SHOW_ALL_UNTRACKED_FILES;
 841         else
 842                 die("Invalid untracked files mode '%s'", untracked_files_arg);
 843 }
 844
 845 static int parse_and_validate_options(int argc, const char *argv[],
 846                                       const char * const usage[],
 847                                       const char *prefix,
 848                                       struct wt_status *s)
 849 {
 850         int f = 0;
 851
 852         argc = parse_options(argc, argv, prefix, builtin_commit_options, usage,
 853                              0);
 854
 855         if (force_author && !strchr(force_author, '>'))
 856                 force_author = find_author_by_nickname(force_author);
 857
 858         if (force_author && renew_authorship)
 859                 die("Using both --reset-author and --author does not make sense");
 860
 861         if (logfile || message.len || use_message)
 862                 use_editor = 0;
 863         if (edit_flag)
 864                 use_editor = 1;
 865         if (!use_editor)
 866                 setenv("GIT_EDITOR", ":", 1);
 867
 868         if (get_sha1("HEAD", head_sha1))
 869                 initial_commit = 1;
 870
 871         /* Sanity check options */
 872         if (amend && initial_commit)
 873                 die("You have nothing to amend.");
 874         if (amend && in_merge)
 875                 die("You are in the middle of a merge -- cannot amend.");
 876
 877         if (use_message)
 878                 f++;
 879         if (edit_message)
 880                 f++;
 881         if (logfile)
 882                 f++;
 883         if (f > 1)
 884                 die("Only one of -c/-C/-F can be used.");
 885         if (message.len && f > 0)
 886                 die("Option -m cannot be combined with -c/-C/-F.");
 887         if (edit_message)
 888                 use_message = edit_message;
 889         if (amend && !use_message)
 890                 use_message = "HEAD";
 891         if (!use_message && renew_authorship)
 892                 die("--reset-author can be used only with -C, -c or --amend.");
 893         if (use_message) {
 894                 unsigned char sha1[20];
 895                 static char utf8[] = "UTF-8";
 896                 const char *out_enc;
 897                 char *enc, *end;
 898                 struct commit *commit;
 899
 900                 if (get_sha1(use_message, sha1))
 901                         die("could not lookup commit %s", use_message);
 902                 commit = lookup_commit_reference(sha1);
 903                 if (!commit || parse_commit(commit))
 904                         die("could not parse commit %s", use_message);
 905
 906                 enc = strstr(commit->buffer, "\nencoding");
 907                 if (enc) {
 908                         end = strchr(enc + 10, '\n');
 909                         enc = xstrndup(enc + 10, end - (enc + 10));
 910                 } else {
 911                         enc = utf8;
 912                 }
 913                 out_enc = git_commit_encoding ? git_commit_encoding : utf8;
 914
 915                 if (strcmp(out_enc, enc))
 916                         use_message_buffer =
 917                                 reencode_string(commit->buffer, out_enc, enc);
 918
 919                 /*
 920                  * If we failed to reencode the buffer, just copy it
 921                  * byte for byte so the user can try to fix it up.
 922                  * This also handles the case where input and output
 923                  * encodings are identical.
 924                  */
 925                 if (use_message_buffer == NULL)
 926                         use_message_buffer = xstrdup(commit->buffer);
 927                 if (enc != utf8)
 928                         free(enc);
 929         }
 930
 931         if (!!also + !!only + !!all + !!interactive > 1)
 932                 die("Only one of --include/--only/--all/--interactive can be used.");
 933         if (argc == 0 && (also || (only && !amend)))
 934                 die("No paths with --include/--only does not make sense.");
 935         if (argc == 0 && only && amend)
 936                 only_include_assumed = "Clever... amending the last one with dirty index.";
 937         if (argc > 0 && !also && !only)
 938                 only_include_assumed = "Explicit paths specified without -i nor -o; assuming --only paths...";
 939         if (!cleanup_arg || !strcmp(cleanup_arg, "default"))
 940                 cleanup_mode = use_editor ? CLEANUP_ALL : CLEANUP_SPACE;
 941         else if (!strcmp(cleanup_arg, "verbatim"))
 942                 cleanup_mode = CLEANUP_NONE;
 943         else if (!strcmp(cleanup_arg, "whitespace"))
 944                 cleanup_mode = CLEANUP_SPACE;
 945         else if (!strcmp(cleanup_arg, "strip"))
 946                 cleanup_mode = CLEANUP_ALL;
 947         else
 948                 die("Invalid cleanup mode %s", cleanup_arg);
 949
 950         handle_untracked_files_arg(s);
 951
 952         if (all && argc > 0)
 953                 die("Paths with -a does not make sense.");
 954         else if (interactive && argc > 0)
 955                 die("Paths with --interactive does not make sense.");
 956
 957         if (null_termination && status_format == STATUS_FORMAT_LONG)
 958                 status_format = STATUS_FORMAT_PORCELAIN;
 959         if (status_format != STATUS_FORMAT_LONG)
 960                 dry_run = 1;
 961
 962         return argc;
 963 }
 964
 965 static int dry_run_commit(int argc, const char **argv, const char *prefix,
 966                           struct wt_status *s)
 967 {
 968         int commitable;
 969         const char *index_file;
 970
 971         index_file = prepare_index(argc, argv, prefix, 1);
 972         commitable = run_status(stdout, index_file, prefix, 0, s);
 973         rollback_index_files();
 974
 975         return commitable ? 0 : 1;
 976 }
 977
 978 static int parse_status_slot(const char *var, int offset)
 979 {
 980         if (!strcasecmp(var+offset, "header"))
 981                 return WT_STATUS_HEADER;
 982         if (!strcasecmp(var+offset, "updated")
 983                 || !strcasecmp(var+offset, "added"))
 984                 return WT_STATUS_UPDATED;
 985         if (!strcasecmp(var+offset, "changed"))
 986                 return WT_STATUS_CHANGED;
 987         if (!strcasecmp(var+offset, "untracked"))
 988                 return WT_STATUS_UNTRACKED;
 989         if (!strcasecmp(var+offset, "nobranch"))
 990                 return WT_STATUS_NOBRANCH;
 991         if (!strcasecmp(var+offset, "unmerged"))
 992                 return WT_STATUS_UNMERGED;
 993         return -1;
 994 }
 995
 996 static int git_status_config(const char *k, const char *v, void *cb)
 997 {
 998         struct wt_status *s = cb;
 999
1000         if (!strcmp(k, "status.submodulesummary")) {
1001                 int is_bool;
1002                 s->submodule_summary = git_config_bool_or_int(k, v, &is_bool);
1003                 if (is_bool && s->submodule_summary)
1004                         s->submodule_summary = -1;
1005                 return 0;
1006         }
1007         if (!strcmp(k, "status.color") || !strcmp(k, "color.status")) {
1008                 s->use_color = git_config_colorbool(k, v, -1);
1009                 return 0;
1010         }
1011         if (!prefixcmp(k, "status.color.") || !prefixcmp(k, "color.status.")) {
1012                 int slot = parse_status_slot(k, 13);
1013                 if (slot < 0)
1014                         return 0;
1015                 if (!v)
1016                         return config_error_nonbool(k);
1017                 color_parse(v, k, s->color_palette[slot]);
1018                 return 0;
1019         }
1020         if (!strcmp(k, "status.relativepaths")) {
1021                 s->relative_paths = git_config_bool(k, v);
1022                 return 0;
1023         }
1024         if (!strcmp(k, "status.showuntrackedfiles")) {
1025                 if (!v)
1026                         return config_error_nonbool(k);
1027                 else if (!strcmp(v, "no"))
1028                         s->show_untracked_files = SHOW_NO_UNTRACKED_FILES;
1029                 else if (!strcmp(v, "normal"))
1030                         s->show_untracked_files = SHOW_NORMAL_UNTRACKED_FILES;
1031                 else if (!strcmp(v, "all"))
1032                         s->show_untracked_files = SHOW_ALL_UNTRACKED_FILES;
1033                 else
1034                         return error("Invalid untracked files mode '%s'", v);
1035                 return 0;
1036         }
1037         return git_diff_ui_config(k, v, NULL);
1038 }
1039
1040 int cmd_status(int argc, const char **argv, const char *prefix)
1041 {
1042         struct wt_status s;
1043         int fd;
1044         unsigned char sha1[20];
1045         static struct option builtin_status_options[] = {
1046                 OPT__VERBOSE(&verbose),
1047                 OPT_SET_INT('s', "short", &status_format,
1048                             "show status concisely", STATUS_FORMAT_SHORT),
1049                 OPT_BOOLEAN('b', "branch", &status_show_branch,
1050                             "show branch information"),
1051                 OPT_SET_INT(0, "porcelain", &status_format,
1052                             "show porcelain output format",
1053                             STATUS_FORMAT_PORCELAIN),
1054                 OPT_BOOLEAN('z', "null", &null_termination,
1055                             "terminate entries with NUL"),
1056                 { OPTION_STRING, 'u', "untracked-files", &untracked_files_arg,
1057                   "mode",
1058                   "show untracked files, optional modes: all, normal, no. (Default: all)",
1059                   PARSE_OPT_OPTARG, NULL, (intptr_t)"all" },
1060                 OPT_BOOLEAN(0, "ignored", &show_ignored_in_status,
1061                             "show ignored files"),
1062                 OPT_END(),
1063         };
1064
1065         if (null_termination && status_format == STATUS_FORMAT_LONG)
1066                 status_format = STATUS_FORMAT_PORCELAIN;
1067
1068         wt_status_prepare(&s);
1069         git_config(git_status_config, &s);
1070         in_merge = file_exists(git_path("MERGE_HEAD"));
1071         argc = parse_options(argc, argv, prefix,
1072                              builtin_status_options,
1073                              builtin_status_usage, 0);
1074         handle_untracked_files_arg(&s);
1075         if (show_ignored_in_status)
1076                 s.show_ignored_files = 1;
1077         if (*argv)
1078                 s.pathspec = get_pathspec(prefix, argv);
1079
1080         read_cache_preload(s.pathspec);
1081         refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, s.pathspec, NULL, NULL);
1082
1083         fd = hold_locked_index(&index_lock, 0);
1084         if (0 <= fd) {
1085                 if (!write_cache(fd, active_cache, active_nr))
1086                         commit_locked_index(&index_lock);
1087                 rollback_lock_file(&index_lock);
1088         }
1089
1090         s.is_initial = get_sha1(s.reference, sha1) ? 1 : 0;
1091         s.in_merge = in_merge;
1092         wt_status_collect(&s);
1093
1094         if (s.relative_paths)
1095                 s.prefix = prefix;
1096         if (s.use_color == -1)
1097                 s.use_color = git_use_color_default;
1098         if (diff_use_color_default == -1)
1099                 diff_use_color_default = git_use_color_default;
1100
1101         switch (status_format) {
1102         case STATUS_FORMAT_SHORT:
1103                 wt_shortstatus_print(&s, null_termination, status_show_branch);
1104                 break;
1105         case STATUS_FORMAT_PORCELAIN:
1106                 wt_porcelain_print(&s, null_termination);
1107                 break;
1108         case STATUS_FORMAT_LONG:
1109                 s.verbose = verbose;
1110                 wt_status_print(&s);
1111                 break;
1112         }
1113         return 0;
1114 }
1115
1116 static void print_summary(const char *prefix, const unsigned char *sha1)
1117 {
1118         struct rev_info rev;
1119         struct commit *commit;
1120         struct strbuf format = STRBUF_INIT;
1121         unsigned char junk_sha1[20];
1122         const char *head = resolve_ref("HEAD", junk_sha1, 0, NULL);
1123         struct pretty_print_context pctx = {0};
1124         struct strbuf author_ident = STRBUF_INIT;
1125         struct strbuf committer_ident = STRBUF_INIT;
1126
1127         commit = lookup_commit(sha1);
1128         if (!commit)
1129                 die("couldn't look up newly created commit");
1130         if (!commit || parse_commit(commit))
1131                 die("could not parse newly created commit");
1132
1133         strbuf_addstr(&format, "format:%h] %s");
1134
1135         format_commit_message(commit, "%an <%ae>", &author_ident, &pctx);
1136         format_commit_message(commit, "%cn <%ce>", &committer_ident, &pctx);
1137         if (strbuf_cmp(&author_ident, &committer_ident)) {
1138                 strbuf_addstr(&format, "\n Author: ");
1139                 strbuf_addbuf_percentquote(&format, &author_ident);
1140         }
1141         if (!user_ident_sufficiently_given()) {
1142                 strbuf_addstr(&format, "\n Committer: ");
1143                 strbuf_addbuf_percentquote(&format, &committer_ident);
1144                 if (advice_implicit_identity) {
1145                         strbuf_addch(&format, '\n');
1146                         strbuf_addstr(&format, implicit_ident_advice);
1147                 }
1148         }
1149         strbuf_release(&author_ident);
1150         strbuf_release(&committer_ident);
1151
1152         init_revisions(&rev, prefix);
1153         setup_revisions(0, NULL, &rev, NULL);
1154
1155         rev.abbrev = 0;
1156         rev.diff = 1;
1157         rev.diffopt.output_format =
1158                 DIFF_FORMAT_SHORTSTAT | DIFF_FORMAT_SUMMARY;
1159
1160         rev.verbose_header = 1;
1161         rev.show_root_diff = 1;
1162         get_commit_format(format.buf, &rev);
1163         rev.always_show_header = 0;
1164         rev.diffopt.detect_rename = 1;
1165         rev.diffopt.rename_limit = 100;
1166         rev.diffopt.break_opt = 0;
1167         diff_setup_done(&rev.diffopt);
1168
1169         printf("[%s%s ",
1170                 !prefixcmp(head, "refs/heads/") ?
1171                         head + 11 :
1172                         !strcmp(head, "HEAD") ?
1173                                 "detached HEAD" :
1174                                 head,
1175                 initial_commit ? " (root-commit)" : "");
1176
1177         if (!log_tree_commit(&rev, commit)) {
1178                 rev.always_show_header = 1;
1179                 rev.use_terminator = 1;
1180                 log_tree_commit(&rev, commit);
1181         }
1182
1183         strbuf_release(&format);
1184 }
1185
1186 static int git_commit_config(const char *k, const char *v, void *cb)
1187 {
1188         struct wt_status *s = cb;
1189
1190         if (!strcmp(k, "commit.template"))
1191                 return git_config_pathname(&template_file, k, v);
1192         if (!strcmp(k, "commit.status")) {
1193                 include_status = git_config_bool(k, v);
1194                 return 0;
1195         }
1196
1197         return git_status_config(k, v, s);
1198 }
1199
1200 static const char post_rewrite_hook[] = "hooks/post-rewrite";
1201
1202 static int run_rewrite_hook(const unsigned char *oldsha1,
1203                             const unsigned char *newsha1)
1204 {
1205         /* oldsha1 SP newsha1 LF NUL */
1206         static char buf[2*40 + 3];
1207         struct child_process proc;
1208         const char *argv[3];
1209         int code;
1210         size_t n;
1211
1212         if (access(git_path(post_rewrite_hook), X_OK) < 0)
1213                 return 0;
1214
1215         argv[0] = git_path(post_rewrite_hook);
1216         argv[1] = "amend";
1217         argv[2] = NULL;
1218
1219         memset(&proc, 0, sizeof(proc));
1220         proc.argv = argv;
1221         proc.in = -1;
1222         proc.stdout_to_stderr = 1;
1223
1224         code = start_command(&proc);
1225         if (code)
1226                 return code;
1227         n = snprintf(buf, sizeof(buf), "%s %s\n",
1228                      sha1_to_hex(oldsha1), sha1_to_hex(newsha1));
1229         write_in_full(proc.in, buf, n);
1230         close(proc.in);
1231         return finish_command(&proc);
1232 }
1233
1234 int cmd_commit(int argc, const char **argv, const char *prefix)
1235 {
1236         struct strbuf sb = STRBUF_INIT;
1237         const char *index_file, *reflog_msg;
1238         char *nl, *p;
1239         unsigned char commit_sha1[20];
1240         struct ref_lock *ref_lock;
1241         struct commit_list *parents = NULL, **pptr = &parents;
1242         struct stat statbuf;
1243         int allow_fast_forward = 1;
1244         struct wt_status s;
1245
1246         wt_status_prepare(&s);
1247         git_config(git_commit_config, &s);
1248         in_merge = file_exists(git_path("MERGE_HEAD"));
1249         s.in_merge = in_merge;
1250
1251         if (s.use_color == -1)
1252                 s.use_color = git_use_color_default;
1253         argc = parse_and_validate_options(argc, argv, builtin_commit_usage,
1254                                           prefix, &s);
1255         if (dry_run) {
1256                 if (diff_use_color_default == -1)
1257                         diff_use_color_default = git_use_color_default;
1258                 return dry_run_commit(argc, argv, prefix, &s);
1259         }
1260         index_file = prepare_index(argc, argv, prefix, 0);
1261
1262         /* Set up everything for writing the commit object.  This includes
1263            running hooks, writing the trees, and interacting with the user.  */
1264         if (!prepare_to_commit(index_file, prefix, &s)) {
1265                 rollback_index_files();
1266                 return 1;
1267         }
1268
1269         /* Determine parents */
1270         reflog_msg = getenv("GIT_REFLOG_ACTION");
1271         if (initial_commit) {
1272                 if (!reflog_msg)
1273                         reflog_msg = "commit (initial)";
1274         } else if (amend) {
1275                 struct commit_list *c;
1276                 struct commit *commit;
1277
1278                 if (!reflog_msg)
1279                         reflog_msg = "commit (amend)";
1280                 commit = lookup_commit(head_sha1);
1281                 if (!commit || parse_commit(commit))
1282                         die("could not parse HEAD commit");
1283
1284                 for (c = commit->parents; c; c = c->next)
1285                         pptr = &commit_list_insert(c->item, pptr)->next;
1286         } else if (in_merge) {
1287                 struct strbuf m = STRBUF_INIT;
1288                 FILE *fp;
1289
1290                 if (!reflog_msg)
1291                         reflog_msg = "commit (merge)";
1292                 pptr = &commit_list_insert(lookup_commit(head_sha1), pptr)->next;
1293                 fp = fopen(git_path("MERGE_HEAD"), "r");
1294                 if (fp == NULL)
1295                         die_errno("could not open '%s' for reading",
1296                                   git_path("MERGE_HEAD"));
1297                 while (strbuf_getline(&m, fp, '\n') != EOF) {
1298                         unsigned char sha1[20];
1299                         if (get_sha1_hex(m.buf, sha1) < 0)
1300                                 die("Corrupt MERGE_HEAD file (%s)", m.buf);
1301                         pptr = &commit_list_insert(lookup_commit(sha1), pptr)->next;
1302                 }
1303                 fclose(fp);
1304                 strbuf_release(&m);
1305                 if (!stat(git_path("MERGE_MODE"), &statbuf)) {
1306                         if (strbuf_read_file(&sb, git_path("MERGE_MODE"), 0) < 0)
1307                                 die_errno("could not read MERGE_MODE");
1308                         if (!strcmp(sb.buf, "no-ff"))
1309                                 allow_fast_forward = 0;
1310                 }
1311                 if (allow_fast_forward)
1312                         parents = reduce_heads(parents);
1313         } else {
1314                 if (!reflog_msg)
1315                         reflog_msg = "commit";
1316                 pptr = &commit_list_insert(lookup_commit(head_sha1), pptr)->next;
1317         }
1318
1319         /* Finally, get the commit message */
1320         strbuf_reset(&sb);
1321         if (strbuf_read_file(&sb, git_path(commit_editmsg), 0) < 0) {
1322                 int saved_errno = errno;
1323                 rollback_index_files();
1324                 die("could not read commit message: %s", strerror(saved_errno));
1325         }
1326
1327         /* Truncate the message just before the diff, if any. */
1328         if (verbose) {
1329                 p = strstr(sb.buf, "\ndiff --git ");
1330                 if (p != NULL)
1331                         strbuf_setlen(&sb, p - sb.buf + 1);
1332         }
1333
1334         if (cleanup_mode != CLEANUP_NONE)
1335                 stripspace(&sb, cleanup_mode == CLEANUP_ALL);
1336         if (message_is_empty(&sb) && !allow_empty_message) {
1337                 rollback_index_files();
1338                 fprintf(stderr, "Aborting commit due to empty commit message.\n");
1339                 exit(1);
1340         }
1341
1342         if (commit_tree(sb.buf, active_cache_tree->sha1, parents, commit_sha1,
1343                         fmt_ident(author_name, author_email, author_date,
1344                                 IDENT_ERROR_ON_NO_NAME))) {
1345                 rollback_index_files();
1346                 die("failed to write commit object");
1347         }
1348
1349         ref_lock = lock_any_ref_for_update("HEAD",
1350                                            initial_commit ? NULL : head_sha1,
1351                                            0);
1352
1353         nl = strchr(sb.buf, '\n');
1354         if (nl)
1355                 strbuf_setlen(&sb, nl + 1 - sb.buf);
1356         else
1357                 strbuf_addch(&sb, '\n');
1358         strbuf_insert(&sb, 0, reflog_msg, strlen(reflog_msg));
1359         strbuf_insert(&sb, strlen(reflog_msg), ": ", 2);
1360
1361         if (!ref_lock) {
1362                 rollback_index_files();
1363                 die("cannot lock HEAD ref");
1364         }
1365         if (write_ref_sha1(ref_lock, commit_sha1, sb.buf) < 0) {
1366                 rollback_index_files();
1367                 die("cannot update HEAD ref");
1368         }
1369
1370         unlink(git_path("MERGE_HEAD"));
1371         unlink(git_path("MERGE_MSG"));
1372         unlink(git_path("MERGE_MODE"));
1373         unlink(git_path("SQUASH_MSG"));
1374
1375         if (commit_index_files())
1376                 die ("Repository has been updated, but unable to write\n"
1377                      "new_index file. Check that disk is not full or quota is\n"
1378                      "not exceeded, and then \"git reset HEAD\" to recover.");
1379
1380         rerere(0);
1381         run_hook(get_index_file(), "post-commit", NULL);
1382         if (amend && !no_post_rewrite) {
1383                 struct notes_rewrite_cfg *cfg;
1384                 cfg = init_copy_notes_for_rewrite("amend");
1385                 if (cfg) {
1386                         copy_note_for_rewrite(cfg, head_sha1, commit_sha1);
1387                         finish_copy_notes_for_rewrite(cfg);
1388                 }
1389                 run_rewrite_hook(head_sha1, commit_sha1);
1390         }
1391         if (!quiet)
1392                 print_summary(prefix, commit_sha1);
1393
1394         return 0;
1395 }