Update jk/maint-strbuf-missing-init to builtin/ rename
authorJunio C Hamano <gitster@pobox.com>
Sun, 18 Dec 2011 08:27:59 +0000 (00:27 -0800)
committerJunio C Hamano <gitster@pobox.com>
Sun, 18 Dec 2011 08:28:16 +0000 (00:28 -0800)
1  2 
builtin/commit.c
builtin/merge.c
index 0000000000000000000000000000000000000000,55676fd874466c70445e81c69cf397cd01380aaf..564042de3928ccff7c8ecb739b78ae1fdc890268
mode 000000,100644..100644
--- /dev/null
@@@ -1,0 -1,1310 +1,1310 @@@
 -static struct strbuf message;
+ /*
+  * Builtin "git commit"
+  *
+  * Copyright (c) 2007 Kristian Høgsberg <krh@redhat.com>
+  * Based on git-commit.sh by Junio C Hamano and Linus Torvalds
+  */
+ #include "cache.h"
+ #include "cache-tree.h"
+ #include "color.h"
+ #include "dir.h"
+ #include "builtin.h"
+ #include "diff.h"
+ #include "diffcore.h"
+ #include "commit.h"
+ #include "revision.h"
+ #include "wt-status.h"
+ #include "run-command.h"
+ #include "refs.h"
+ #include "log-tree.h"
+ #include "strbuf.h"
+ #include "utf8.h"
+ #include "parse-options.h"
+ #include "string-list.h"
+ #include "rerere.h"
+ #include "unpack-trees.h"
+ #include "quote.h"
+ static const char * const builtin_commit_usage[] = {
+       "git commit [options] [--] <filepattern>...",
+       NULL
+ };
+ static const char * const builtin_status_usage[] = {
+       "git status [options] [--] <filepattern>...",
+       NULL
+ };
+ static const char implicit_ident_advice[] =
+ "Your name and email address were configured automatically based\n"
+ "on your username and hostname. Please check that they are accurate.\n"
+ "You can suppress this message by setting them explicitly:\n"
+ "\n"
+ "    git config --global user.name Your Name\n"
+ "    git config --global user.email you@example.com\n"
+ "\n"
+ "If the identity used for this commit is wrong, you can fix it with:\n"
+ "\n"
+ "    git commit --amend --author='Your Name <you@example.com>'\n";
+ static unsigned char head_sha1[20];
+ static char *use_message_buffer;
+ static const char commit_editmsg[] = "COMMIT_EDITMSG";
+ static struct lock_file index_lock; /* real index */
+ static struct lock_file false_lock; /* used only for partial commits */
+ static enum {
+       COMMIT_AS_IS = 1,
+       COMMIT_NORMAL,
+       COMMIT_PARTIAL,
+ } commit_style;
+ static const char *logfile, *force_author;
+ static const char *template_file;
+ static char *edit_message, *use_message;
+ static char *author_name, *author_email, *author_date;
+ static int all, edit_flag, also, interactive, only, amend, signoff;
+ static int quiet, verbose, no_verify, allow_empty, dry_run, renew_authorship;
+ static char *untracked_files_arg, *force_date;
+ /*
+  * The default commit message cleanup mode will remove the lines
+  * beginning with # (shell comments) and leading and trailing
+  * whitespaces (empty lines or containing only whitespaces)
+  * if editor is used, and only the whitespaces if the message
+  * is specified explicitly.
+  */
+ static enum {
+       CLEANUP_SPACE,
+       CLEANUP_NONE,
+       CLEANUP_ALL,
+ } cleanup_mode;
+ static char *cleanup_arg;
+ static int use_editor = 1, initial_commit, in_merge, include_status = 1;
+ static const char *only_include_assumed;
++static struct strbuf message = STRBUF_INIT;
+ static int null_termination;
+ static enum {
+       STATUS_FORMAT_LONG,
+       STATUS_FORMAT_SHORT,
+       STATUS_FORMAT_PORCELAIN,
+ } status_format = STATUS_FORMAT_LONG;
+ static int opt_parse_m(const struct option *opt, const char *arg, int unset)
+ {
+       struct strbuf *buf = opt->value;
+       if (unset)
+               strbuf_setlen(buf, 0);
+       else {
+               strbuf_addstr(buf, arg);
+               strbuf_addstr(buf, "\n\n");
+       }
+       return 0;
+ }
+ static struct option builtin_commit_options[] = {
+       OPT__QUIET(&quiet),
+       OPT__VERBOSE(&verbose),
+       OPT_GROUP("Commit message options"),
+       OPT_FILENAME('F', "file", &logfile, "read log from file"),
+       OPT_STRING(0, "author", &force_author, "AUTHOR", "override author for commit"),
+       OPT_STRING(0, "date", &force_date, "DATE", "override date for commit"),
+       OPT_CALLBACK('m', "message", &message, "MESSAGE", "specify commit message", opt_parse_m),
+       OPT_STRING('c', "reedit-message", &edit_message, "COMMIT", "reuse and edit message from specified commit"),
+       OPT_STRING('C', "reuse-message", &use_message, "COMMIT", "reuse message from specified commit"),
+       OPT_BOOLEAN(0, "reset-author", &renew_authorship, "the commit is authored by me now (used with -C-c/--amend)"),
+       OPT_BOOLEAN('s', "signoff", &signoff, "add Signed-off-by:"),
+       OPT_FILENAME('t', "template", &template_file, "use specified template file"),
+       OPT_BOOLEAN('e', "edit", &edit_flag, "force edit of commit"),
+       OPT_STRING(0, "cleanup", &cleanup_arg, "default", "how to strip spaces and #comments from message"),
+       OPT_BOOLEAN(0, "status", &include_status, "include status in commit message template"),
+       /* end commit message options */
+       OPT_GROUP("Commit contents options"),
+       OPT_BOOLEAN('a', "all", &all, "commit all changed files"),
+       OPT_BOOLEAN('i', "include", &also, "add specified files to index for commit"),
+       OPT_BOOLEAN(0, "interactive", &interactive, "interactively add files"),
+       OPT_BOOLEAN('o', "only", &only, "commit only specified files"),
+       OPT_BOOLEAN('n', "no-verify", &no_verify, "bypass pre-commit hook"),
+       OPT_BOOLEAN(0, "dry-run", &dry_run, "show what would be committed"),
+       OPT_SET_INT(0, "short", &status_format, "show status concisely",
+                   STATUS_FORMAT_SHORT),
+       OPT_SET_INT(0, "porcelain", &status_format,
+                   "show porcelain output format", STATUS_FORMAT_PORCELAIN),
+       OPT_BOOLEAN('z', "null", &null_termination,
+                   "terminate entries with NUL"),
+       OPT_BOOLEAN(0, "amend", &amend, "amend previous commit"),
+       { 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" },
+       OPT_BOOLEAN(0, "allow-empty", &allow_empty, "ok to record an empty change"),
+       /* end commit contents options */
+       OPT_END()
+ };
+ static void rollback_index_files(void)
+ {
+       switch (commit_style) {
+       case COMMIT_AS_IS:
+               break; /* nothing to do */
+       case COMMIT_NORMAL:
+               rollback_lock_file(&index_lock);
+               break;
+       case COMMIT_PARTIAL:
+               rollback_lock_file(&index_lock);
+               rollback_lock_file(&false_lock);
+               break;
+       }
+ }
+ static int commit_index_files(void)
+ {
+       int err = 0;
+       switch (commit_style) {
+       case COMMIT_AS_IS:
+               break; /* nothing to do */
+       case COMMIT_NORMAL:
+               err = commit_lock_file(&index_lock);
+               break;
+       case COMMIT_PARTIAL:
+               err = commit_lock_file(&index_lock);
+               rollback_lock_file(&false_lock);
+               break;
+       }
+       return err;
+ }
+ /*
+  * Take a union of paths in the index and the named tree (typically, "HEAD"),
+  * and return the paths that match the given pattern in list.
+  */
+ static int list_paths(struct string_list *list, const char *with_tree,
+                     const char *prefix, const char **pattern)
+ {
+       int i;
+       char *m;
+       for (i = 0; pattern[i]; i++)
+               ;
+       m = xcalloc(1, i);
+       if (with_tree)
+               overlay_tree_on_cache(with_tree, prefix);
+       for (i = 0; i < active_nr; i++) {
+               struct cache_entry *ce = active_cache[i];
+               struct string_list_item *item;
+               if (ce->ce_flags & CE_UPDATE)
+                       continue;
+               if (!match_pathspec(pattern, ce->name, ce_namelen(ce), 0, m))
+                       continue;
+               item = string_list_insert(ce->name, list);
+               if (ce_skip_worktree(ce))
+                       item->util = item; /* better a valid pointer than a fake one */
+       }
+       return report_path_error(m, pattern, prefix ? strlen(prefix) : 0);
+ }
+ static void add_remove_files(struct string_list *list)
+ {
+       int i;
+       for (i = 0; i < list->nr; i++) {
+               struct stat st;
+               struct string_list_item *p = &(list->items[i]);
+               /* p->util is skip-worktree */
+               if (p->util)
+                       continue;
+               if (!lstat(p->string, &st)) {
+                       if (add_to_cache(p->string, &st, 0))
+                               die("updating files failed");
+               } else
+                       remove_file_from_cache(p->string);
+       }
+ }
+ static void create_base_index(void)
+ {
+       struct tree *tree;
+       struct unpack_trees_options opts;
+       struct tree_desc t;
+       if (initial_commit) {
+               discard_cache();
+               return;
+       }
+       memset(&opts, 0, sizeof(opts));
+       opts.head_idx = 1;
+       opts.index_only = 1;
+       opts.merge = 1;
+       opts.src_index = &the_index;
+       opts.dst_index = &the_index;
+       opts.fn = oneway_merge;
+       tree = parse_tree_indirect(head_sha1);
+       if (!tree)
+               die("failed to unpack HEAD tree object");
+       parse_tree(tree);
+       init_tree_desc(&t, tree->buffer, tree->size);
+       if (unpack_trees(1, &t, &opts))
+               exit(128); /* We've already reported the error, finish dying */
+ }
+ static void refresh_cache_or_die(int refresh_flags)
+ {
+       /*
+        * refresh_flags contains REFRESH_QUIET, so the only errors
+        * are for unmerged entries.
+        */
+       if (refresh_cache(refresh_flags | REFRESH_IN_PORCELAIN))
+               die_resolve_conflict("commit");
+ }
+ static char *prepare_index(int argc, const char **argv, const char *prefix, int is_status)
+ {
+       int fd;
+       struct string_list partial;
+       const char **pathspec = NULL;
+       int refresh_flags = REFRESH_QUIET;
+       if (is_status)
+               refresh_flags |= REFRESH_UNMERGED;
+       if (interactive) {
+               if (interactive_add(argc, argv, prefix) != 0)
+                       die("interactive add failed");
+               if (read_cache_preload(NULL) < 0)
+                       die("index file corrupt");
+               commit_style = COMMIT_AS_IS;
+               return get_index_file();
+       }
+       if (*argv)
+               pathspec = get_pathspec(prefix, argv);
+       if (read_cache_preload(pathspec) < 0)
+               die("index file corrupt");
+       /*
+        * Non partial, non as-is commit.
+        *
+        * (1) get the real index;
+        * (2) update the_index as necessary;
+        * (3) write the_index out to the real index (still locked);
+        * (4) return the name of the locked index file.
+        *
+        * The caller should run hooks on the locked real index, and
+        * (A) if all goes well, commit the real index;
+        * (B) on failure, rollback the real index.
+        */
+       if (all || (also && pathspec && *pathspec)) {
+               int fd = hold_locked_index(&index_lock, 1);
+               add_files_to_cache(also ? prefix : NULL, pathspec, 0);
+               refresh_cache_or_die(refresh_flags);
+               if (write_cache(fd, active_cache, active_nr) ||
+                   close_lock_file(&index_lock))
+                       die("unable to write new_index file");
+               commit_style = COMMIT_NORMAL;
+               return index_lock.filename;
+       }
+       /*
+        * As-is commit.
+        *
+        * (1) return the name of the real index file.
+        *
+        * The caller should run hooks on the real index, and run
+        * hooks on the real index, and create commit from the_index.
+        * We still need to refresh the index here.
+        */
+       if (!pathspec || !*pathspec) {
+               fd = hold_locked_index(&index_lock, 1);
+               refresh_cache_or_die(refresh_flags);
+               if (write_cache(fd, active_cache, active_nr) ||
+                   commit_locked_index(&index_lock))
+                       die("unable to write new_index file");
+               commit_style = COMMIT_AS_IS;
+               return get_index_file();
+       }
+       /*
+        * A partial commit.
+        *
+        * (0) find the set of affected paths;
+        * (1) get lock on the real index file;
+        * (2) update the_index with the given paths;
+        * (3) write the_index out to the real index (still locked);
+        * (4) get lock on the false index file;
+        * (5) reset the_index from HEAD;
+        * (6) update the_index the same way as (2);
+        * (7) write the_index out to the false index file;
+        * (8) return the name of the false index file (still locked);
+        *
+        * The caller should run hooks on the locked false index, and
+        * create commit from it.  Then
+        * (A) if all goes well, commit the real index;
+        * (B) on failure, rollback the real index;
+        * In either case, rollback the false index.
+        */
+       commit_style = COMMIT_PARTIAL;
+       if (in_merge)
+               die("cannot do a partial commit during a merge.");
+       memset(&partial, 0, sizeof(partial));
+       partial.strdup_strings = 1;
+       if (list_paths(&partial, initial_commit ? NULL : "HEAD", prefix, pathspec))
+               exit(1);
+       discard_cache();
+       if (read_cache() < 0)
+               die("cannot read the index");
+       fd = hold_locked_index(&index_lock, 1);
+       add_remove_files(&partial);
+       refresh_cache(REFRESH_QUIET);
+       if (write_cache(fd, active_cache, active_nr) ||
+           close_lock_file(&index_lock))
+               die("unable to write new_index file");
+       fd = hold_lock_file_for_update(&false_lock,
+                                      git_path("next-index-%"PRIuMAX,
+                                               (uintmax_t) getpid()),
+                                      LOCK_DIE_ON_ERROR);
+       create_base_index();
+       add_remove_files(&partial);
+       refresh_cache(REFRESH_QUIET);
+       if (write_cache(fd, active_cache, active_nr) ||
+           close_lock_file(&false_lock))
+               die("unable to write temporary index file");
+       discard_cache();
+       read_cache_from(false_lock.filename);
+       return false_lock.filename;
+ }
+ static int run_status(FILE *fp, const char *index_file, const char *prefix, int nowarn,
+                     struct wt_status *s)
+ {
+       unsigned char sha1[20];
+       if (s->relative_paths)
+               s->prefix = prefix;
+       if (amend) {
+               s->amend = 1;
+               s->reference = "HEAD^1";
+       }
+       s->verbose = verbose;
+       s->index_file = index_file;
+       s->fp = fp;
+       s->nowarn = nowarn;
+       s->is_initial = get_sha1(s->reference, sha1) ? 1 : 0;
+       wt_status_collect(s);
+       switch (status_format) {
+       case STATUS_FORMAT_SHORT:
+               wt_shortstatus_print(s, null_termination);
+               break;
+       case STATUS_FORMAT_PORCELAIN:
+               wt_porcelain_print(s, null_termination);
+               break;
+       case STATUS_FORMAT_LONG:
+               wt_status_print(s);
+               break;
+       }
+       return s->commitable;
+ }
+ static int is_a_merge(const unsigned char *sha1)
+ {
+       struct commit *commit = lookup_commit(sha1);
+       if (!commit || parse_commit(commit))
+               die("could not parse HEAD commit");
+       return !!(commit->parents && commit->parents->next);
+ }
+ static const char sign_off_header[] = "Signed-off-by: ";
+ static void determine_author_info(void)
+ {
+       char *name, *email, *date;
+       name = getenv("GIT_AUTHOR_NAME");
+       email = getenv("GIT_AUTHOR_EMAIL");
+       date = getenv("GIT_AUTHOR_DATE");
+       if (use_message && !renew_authorship) {
+               const char *a, *lb, *rb, *eol;
+               a = strstr(use_message_buffer, "\nauthor ");
+               if (!a)
+                       die("invalid commit: %s", use_message);
+               lb = strstr(a + 8, " <");
+               rb = strstr(a + 8, "> ");
+               eol = strchr(a + 8, '\n');
+               if (!lb || !rb || !eol)
+                       die("invalid commit: %s", use_message);
+               name = xstrndup(a + 8, lb - (a + 8));
+               email = xstrndup(lb + 2, rb - (lb + 2));
+               date = xstrndup(rb + 2, eol - (rb + 2));
+       }
+       if (force_author) {
+               const char *lb = strstr(force_author, " <");
+               const char *rb = strchr(force_author, '>');
+               if (!lb || !rb)
+                       die("malformed --author parameter");
+               name = xstrndup(force_author, lb - force_author);
+               email = xstrndup(lb + 2, rb - (lb + 2));
+       }
+       if (force_date)
+               date = force_date;
+       author_name = name;
+       author_email = email;
+       author_date = date;
+ }
+ static int ends_rfc2822_footer(struct strbuf *sb)
+ {
+       int ch;
+       int hit = 0;
+       int i, j, k;
+       int len = sb->len;
+       int first = 1;
+       const char *buf = sb->buf;
+       for (i = len - 1; i > 0; i--) {
+               if (hit && buf[i] == '\n')
+                       break;
+               hit = (buf[i] == '\n');
+       }
+       while (i < len - 1 && buf[i] == '\n')
+               i++;
+       for (; i < len; i = k) {
+               for (k = i; k < len && buf[k] != '\n'; k++)
+                       ; /* do nothing */
+               k++;
+               if ((buf[k] == ' ' || buf[k] == '\t') && !first)
+                       continue;
+               first = 0;
+               for (j = 0; i + j < len; j++) {
+                       ch = buf[i + j];
+                       if (ch == ':')
+                               break;
+                       if (isalnum(ch) ||
+                           (ch == '-'))
+                               continue;
+                       return 0;
+               }
+       }
+       return 1;
+ }
+ static int prepare_to_commit(const char *index_file, const char *prefix,
+                            struct wt_status *s)
+ {
+       struct stat statbuf;
+       int commitable, saved_color_setting;
+       struct strbuf sb = STRBUF_INIT;
+       char *buffer;
+       FILE *fp;
+       const char *hook_arg1 = NULL;
+       const char *hook_arg2 = NULL;
+       int ident_shown = 0;
+       if (!no_verify && run_hook(index_file, "pre-commit", NULL))
+               return 0;
+       if (message.len) {
+               strbuf_addbuf(&sb, &message);
+               hook_arg1 = "message";
+       } else if (logfile && !strcmp(logfile, "-")) {
+               if (isatty(0))
+                       fprintf(stderr, "(reading log message from standard input)\n");
+               if (strbuf_read(&sb, 0, 0) < 0)
+                       die_errno("could not read log from standard input");
+               hook_arg1 = "message";
+       } else if (logfile) {
+               if (strbuf_read_file(&sb, logfile, 0) < 0)
+                       die_errno("could not read log file '%s'",
+                                 logfile);
+               hook_arg1 = "message";
+       } else if (use_message) {
+               buffer = strstr(use_message_buffer, "\n\n");
+               if (!buffer || buffer[2] == '\0')
+                       die("commit has empty message");
+               strbuf_add(&sb, buffer + 2, strlen(buffer + 2));
+               hook_arg1 = "commit";
+               hook_arg2 = use_message;
+       } else if (!stat(git_path("MERGE_MSG"), &statbuf)) {
+               if (strbuf_read_file(&sb, git_path("MERGE_MSG"), 0) < 0)
+                       die_errno("could not read MERGE_MSG");
+               hook_arg1 = "merge";
+       } else if (!stat(git_path("SQUASH_MSG"), &statbuf)) {
+               if (strbuf_read_file(&sb, git_path("SQUASH_MSG"), 0) < 0)
+                       die_errno("could not read SQUASH_MSG");
+               hook_arg1 = "squash";
+       } else if (template_file && !stat(template_file, &statbuf)) {
+               if (strbuf_read_file(&sb, template_file, 0) < 0)
+                       die_errno("could not read '%s'", template_file);
+               hook_arg1 = "template";
+       }
+       /*
+        * This final case does not modify the template message,
+        * it just sets the argument to the prepare-commit-msg hook.
+        */
+       else if (in_merge)
+               hook_arg1 = "merge";
+       fp = fopen(git_path(commit_editmsg), "w");
+       if (fp == NULL)
+               die_errno("could not open '%s'", git_path(commit_editmsg));
+       if (cleanup_mode != CLEANUP_NONE)
+               stripspace(&sb, 0);
+       if (signoff) {
+               struct strbuf sob = STRBUF_INIT;
+               int i;
+               strbuf_addstr(&sob, sign_off_header);
+               strbuf_addstr(&sob, fmt_name(getenv("GIT_COMMITTER_NAME"),
+                                            getenv("GIT_COMMITTER_EMAIL")));
+               strbuf_addch(&sob, '\n');
+               for (i = sb.len - 1; i > 0 && sb.buf[i - 1] != '\n'; i--)
+                       ; /* do nothing */
+               if (prefixcmp(sb.buf + i, sob.buf)) {
+                       if (!i || !ends_rfc2822_footer(&sb))
+                               strbuf_addch(&sb, '\n');
+                       strbuf_addbuf(&sb, &sob);
+               }
+               strbuf_release(&sob);
+       }
+       if (fwrite(sb.buf, 1, sb.len, fp) < sb.len)
+               die_errno("could not write commit template");
+       strbuf_release(&sb);
+       determine_author_info();
+       /* This checks if committer ident is explicitly given */
+       git_committer_info(0);
+       if (use_editor && include_status) {
+               char *author_ident;
+               const char *committer_ident;
+               if (in_merge)
+                       fprintf(fp,
+                               "#\n"
+                               "# It looks like you may be committing a MERGE.\n"
+                               "# If this is not correct, please remove the file\n"
+                               "#      %s\n"
+                               "# and try again.\n"
+                               "#\n",
+                               git_path("MERGE_HEAD"));
+               fprintf(fp,
+                       "\n"
+                       "# Please enter the commit message for your changes.");
+               if (cleanup_mode == CLEANUP_ALL)
+                       fprintf(fp,
+                               " Lines starting\n"
+                               "# with '#' will be ignored, and an empty"
+                               " message aborts the commit.\n");
+               else /* CLEANUP_SPACE, that is. */
+                       fprintf(fp,
+                               " Lines starting\n"
+                               "# with '#' will be kept; you may remove them"
+                               " yourself if you want to.\n"
+                               "# An empty message aborts the commit.\n");
+               if (only_include_assumed)
+                       fprintf(fp, "# %s\n", only_include_assumed);
+               author_ident = xstrdup(fmt_name(author_name, author_email));
+               committer_ident = fmt_name(getenv("GIT_COMMITTER_NAME"),
+                                          getenv("GIT_COMMITTER_EMAIL"));
+               if (strcmp(author_ident, committer_ident))
+                       fprintf(fp,
+                               "%s"
+                               "# Author:    %s\n",
+                               ident_shown++ ? "" : "#\n",
+                               author_ident);
+               free(author_ident);
+               if (!user_ident_sufficiently_given())
+                       fprintf(fp,
+                               "%s"
+                               "# Committer: %s\n",
+                               ident_shown++ ? "" : "#\n",
+                               committer_ident);
+               if (ident_shown)
+                       fprintf(fp, "#\n");
+               saved_color_setting = s->use_color;
+               s->use_color = 0;
+               commitable = run_status(fp, index_file, prefix, 1, s);
+               s->use_color = saved_color_setting;
+       } else {
+               unsigned char sha1[20];
+               const char *parent = "HEAD";
+               if (!active_nr && read_cache() < 0)
+                       die("Cannot read index");
+               if (amend)
+                       parent = "HEAD^1";
+               if (get_sha1(parent, sha1))
+                       commitable = !!active_nr;
+               else
+                       commitable = index_differs_from(parent, 0);
+       }
+       fclose(fp);
+       if (!commitable && !in_merge && !allow_empty &&
+           !(amend && is_a_merge(head_sha1))) {
+               run_status(stdout, index_file, prefix, 0, s);
+               return 0;
+       }
+       /*
+        * Re-read the index as pre-commit hook could have updated it,
+        * and write it out as a tree.  We must do this before we invoke
+        * the editor and after we invoke run_status above.
+        */
+       discard_cache();
+       read_cache_from(index_file);
+       if (!active_cache_tree)
+               active_cache_tree = cache_tree();
+       if (cache_tree_update(active_cache_tree,
+                             active_cache, active_nr, 0, 0) < 0) {
+               error("Error building trees");
+               return 0;
+       }
+       if (run_hook(index_file, "prepare-commit-msg",
+                    git_path(commit_editmsg), hook_arg1, hook_arg2, NULL))
+               return 0;
+       if (use_editor) {
+               char index[PATH_MAX];
+               const char *env[2] = { index, NULL };
+               snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
+               if (launch_editor(git_path(commit_editmsg), NULL, env)) {
+                       fprintf(stderr,
+                       "Please supply the message using either -m or -F option.\n");
+                       exit(1);
+               }
+       }
+       if (!no_verify &&
+           run_hook(index_file, "commit-msg", git_path(commit_editmsg), NULL)) {
+               return 0;
+       }
+       return 1;
+ }
+ /*
+  * Find out if the message in the strbuf contains only whitespace and
+  * Signed-off-by lines.
+  */
+ static int message_is_empty(struct strbuf *sb)
+ {
+       struct strbuf tmpl = STRBUF_INIT;
+       const char *nl;
+       int eol, i, start = 0;
+       if (cleanup_mode == CLEANUP_NONE && sb->len)
+               return 0;
+       /* See if the template is just a prefix of the message. */
+       if (template_file && strbuf_read_file(&tmpl, template_file, 0) > 0) {
+               stripspace(&tmpl, cleanup_mode == CLEANUP_ALL);
+               if (start + tmpl.len <= sb->len &&
+                   memcmp(tmpl.buf, sb->buf + start, tmpl.len) == 0)
+                       start += tmpl.len;
+       }
+       strbuf_release(&tmpl);
+       /* Check if the rest is just whitespace and Signed-of-by's. */
+       for (i = start; i < sb->len; i++) {
+               nl = memchr(sb->buf + i, '\n', sb->len - i);
+               if (nl)
+                       eol = nl - sb->buf;
+               else
+                       eol = sb->len;
+               if (strlen(sign_off_header) <= eol - i &&
+                   !prefixcmp(sb->buf + i, sign_off_header)) {
+                       i = eol;
+                       continue;
+               }
+               while (i < eol)
+                       if (!isspace(sb->buf[i++]))
+                               return 0;
+       }
+       return 1;
+ }
+ static const char *find_author_by_nickname(const char *name)
+ {
+       struct rev_info revs;
+       struct commit *commit;
+       struct strbuf buf = STRBUF_INIT;
+       const char *av[20];
+       int ac = 0;
+       init_revisions(&revs, NULL);
+       strbuf_addf(&buf, "--author=%s", name);
+       av[++ac] = "--all";
+       av[++ac] = "-i";
+       av[++ac] = buf.buf;
+       av[++ac] = NULL;
+       setup_revisions(ac, av, &revs, NULL);
+       prepare_revision_walk(&revs);
+       commit = get_revision(&revs);
+       if (commit) {
+               struct pretty_print_context ctx = {0};
+               ctx.date_mode = DATE_NORMAL;
+               strbuf_release(&buf);
+               format_commit_message(commit, "%an <%ae>", &buf, &ctx);
+               return strbuf_detach(&buf, NULL);
+       }
+       die("No existing author found with '%s'", name);
+ }
+ static void handle_untracked_files_arg(struct wt_status *s)
+ {
+       if (!untracked_files_arg)
+               ; /* default already initialized */
+       else if (!strcmp(untracked_files_arg, "no"))
+               s->show_untracked_files = SHOW_NO_UNTRACKED_FILES;
+       else if (!strcmp(untracked_files_arg, "normal"))
+               s->show_untracked_files = SHOW_NORMAL_UNTRACKED_FILES;
+       else if (!strcmp(untracked_files_arg, "all"))
+               s->show_untracked_files = SHOW_ALL_UNTRACKED_FILES;
+       else
+               die("Invalid untracked files mode '%s'", untracked_files_arg);
+ }
+ static int parse_and_validate_options(int argc, const char *argv[],
+                                     const char * const usage[],
+                                     const char *prefix,
+                                     struct wt_status *s)
+ {
+       int f = 0;
+       argc = parse_options(argc, argv, prefix, builtin_commit_options, usage,
+                            0);
+       if (force_author && !strchr(force_author, '>'))
+               force_author = find_author_by_nickname(force_author);
+       if (force_author && renew_authorship)
+               die("Using both --reset-author and --author does not make sense");
+       if (logfile || message.len || use_message)
+               use_editor = 0;
+       if (edit_flag)
+               use_editor = 1;
+       if (!use_editor)
+               setenv("GIT_EDITOR", ":", 1);
+       if (get_sha1("HEAD", head_sha1))
+               initial_commit = 1;
+       /* Sanity check options */
+       if (amend && initial_commit)
+               die("You have nothing to amend.");
+       if (amend && in_merge)
+               die("You are in the middle of a merge -- cannot amend.");
+       if (use_message)
+               f++;
+       if (edit_message)
+               f++;
+       if (logfile)
+               f++;
+       if (f > 1)
+               die("Only one of -c/-C/-F can be used.");
+       if (message.len && f > 0)
+               die("Option -m cannot be combined with -c/-C/-F.");
+       if (edit_message)
+               use_message = edit_message;
+       if (amend && !use_message)
+               use_message = "HEAD";
+       if (!use_message && renew_authorship)
+               die("--reset-author can be used only with -C, -c or --amend.");
+       if (use_message) {
+               unsigned char sha1[20];
+               static char utf8[] = "UTF-8";
+               const char *out_enc;
+               char *enc, *end;
+               struct commit *commit;
+               if (get_sha1(use_message, sha1))
+                       die("could not lookup commit %s", use_message);
+               commit = lookup_commit_reference(sha1);
+               if (!commit || parse_commit(commit))
+                       die("could not parse commit %s", use_message);
+               enc = strstr(commit->buffer, "\nencoding");
+               if (enc) {
+                       end = strchr(enc + 10, '\n');
+                       enc = xstrndup(enc + 10, end - (enc + 10));
+               } else {
+                       enc = utf8;
+               }
+               out_enc = git_commit_encoding ? git_commit_encoding : utf8;
+               if (strcmp(out_enc, enc))
+                       use_message_buffer =
+                               reencode_string(commit->buffer, out_enc, enc);
+               /*
+                * If we failed to reencode the buffer, just copy it
+                * byte for byte so the user can try to fix it up.
+                * This also handles the case where input and output
+                * encodings are identical.
+                */
+               if (use_message_buffer == NULL)
+                       use_message_buffer = xstrdup(commit->buffer);
+               if (enc != utf8)
+                       free(enc);
+       }
+       if (!!also + !!only + !!all + !!interactive > 1)
+               die("Only one of --include/--only/--all/--interactive can be used.");
+       if (argc == 0 && (also || (only && !amend)))
+               die("No paths with --include/--only does not make sense.");
+       if (argc == 0 && only && amend)
+               only_include_assumed = "Clever... amending the last one with dirty index.";
+       if (argc > 0 && !also && !only)
+               only_include_assumed = "Explicit paths specified without -i nor -o; assuming --only paths...";
+       if (!cleanup_arg || !strcmp(cleanup_arg, "default"))
+               cleanup_mode = use_editor ? CLEANUP_ALL : CLEANUP_SPACE;
+       else if (!strcmp(cleanup_arg, "verbatim"))
+               cleanup_mode = CLEANUP_NONE;
+       else if (!strcmp(cleanup_arg, "whitespace"))
+               cleanup_mode = CLEANUP_SPACE;
+       else if (!strcmp(cleanup_arg, "strip"))
+               cleanup_mode = CLEANUP_ALL;
+       else
+               die("Invalid cleanup mode %s", cleanup_arg);
+       handle_untracked_files_arg(s);
+       if (all && argc > 0)
+               die("Paths with -a does not make sense.");
+       else if (interactive && argc > 0)
+               die("Paths with --interactive does not make sense.");
+       if (null_termination && status_format == STATUS_FORMAT_LONG)
+               status_format = STATUS_FORMAT_PORCELAIN;
+       if (status_format != STATUS_FORMAT_LONG)
+               dry_run = 1;
+       return argc;
+ }
+ static int dry_run_commit(int argc, const char **argv, const char *prefix,
+                         struct wt_status *s)
+ {
+       int commitable;
+       const char *index_file;
+       index_file = prepare_index(argc, argv, prefix, 1);
+       commitable = run_status(stdout, index_file, prefix, 0, s);
+       rollback_index_files();
+       return commitable ? 0 : 1;
+ }
+ static int parse_status_slot(const char *var, int offset)
+ {
+       if (!strcasecmp(var+offset, "header"))
+               return WT_STATUS_HEADER;
+       if (!strcasecmp(var+offset, "updated")
+               || !strcasecmp(var+offset, "added"))
+               return WT_STATUS_UPDATED;
+       if (!strcasecmp(var+offset, "changed"))
+               return WT_STATUS_CHANGED;
+       if (!strcasecmp(var+offset, "untracked"))
+               return WT_STATUS_UNTRACKED;
+       if (!strcasecmp(var+offset, "nobranch"))
+               return WT_STATUS_NOBRANCH;
+       if (!strcasecmp(var+offset, "unmerged"))
+               return WT_STATUS_UNMERGED;
+       return -1;
+ }
+ static int git_status_config(const char *k, const char *v, void *cb)
+ {
+       struct wt_status *s = cb;
+       if (!strcmp(k, "status.submodulesummary")) {
+               int is_bool;
+               s->submodule_summary = git_config_bool_or_int(k, v, &is_bool);
+               if (is_bool && s->submodule_summary)
+                       s->submodule_summary = -1;
+               return 0;
+       }
+       if (!strcmp(k, "status.color") || !strcmp(k, "color.status")) {
+               s->use_color = git_config_colorbool(k, v, -1);
+               return 0;
+       }
+       if (!prefixcmp(k, "status.color.") || !prefixcmp(k, "color.status.")) {
+               int slot = parse_status_slot(k, 13);
+               if (slot < 0)
+                       return 0;
+               if (!v)
+                       return config_error_nonbool(k);
+               color_parse(v, k, s->color_palette[slot]);
+               return 0;
+       }
+       if (!strcmp(k, "status.relativepaths")) {
+               s->relative_paths = git_config_bool(k, v);
+               return 0;
+       }
+       if (!strcmp(k, "status.showuntrackedfiles")) {
+               if (!v)
+                       return config_error_nonbool(k);
+               else if (!strcmp(v, "no"))
+                       s->show_untracked_files = SHOW_NO_UNTRACKED_FILES;
+               else if (!strcmp(v, "normal"))
+                       s->show_untracked_files = SHOW_NORMAL_UNTRACKED_FILES;
+               else if (!strcmp(v, "all"))
+                       s->show_untracked_files = SHOW_ALL_UNTRACKED_FILES;
+               else
+                       return error("Invalid untracked files mode '%s'", v);
+               return 0;
+       }
+       return git_diff_ui_config(k, v, NULL);
+ }
+ int cmd_status(int argc, const char **argv, const char *prefix)
+ {
+       struct wt_status s;
+       unsigned char sha1[20];
+       static struct option builtin_status_options[] = {
+               OPT__VERBOSE(&verbose),
+               OPT_SET_INT('s', "short", &status_format,
+                           "show status concisely", STATUS_FORMAT_SHORT),
+               OPT_SET_INT(0, "porcelain", &status_format,
+                           "show porcelain output format",
+                           STATUS_FORMAT_PORCELAIN),
+               OPT_BOOLEAN('z', "null", &null_termination,
+                           "terminate entries with NUL"),
+               { 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" },
+               OPT_END(),
+       };
+       if (null_termination && status_format == STATUS_FORMAT_LONG)
+               status_format = STATUS_FORMAT_PORCELAIN;
+       wt_status_prepare(&s);
+       git_config(git_status_config, &s);
+       in_merge = file_exists(git_path("MERGE_HEAD"));
+       argc = parse_options(argc, argv, prefix,
+                            builtin_status_options,
+                            builtin_status_usage, 0);
+       handle_untracked_files_arg(&s);
+       if (*argv)
+               s.pathspec = get_pathspec(prefix, argv);
+       read_cache();
+       refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, s.pathspec, NULL, NULL);
+       s.is_initial = get_sha1(s.reference, sha1) ? 1 : 0;
+       s.in_merge = in_merge;
+       wt_status_collect(&s);
+       if (s.relative_paths)
+               s.prefix = prefix;
+       if (s.use_color == -1)
+               s.use_color = git_use_color_default;
+       if (diff_use_color_default == -1)
+               diff_use_color_default = git_use_color_default;
+       switch (status_format) {
+       case STATUS_FORMAT_SHORT:
+               wt_shortstatus_print(&s, null_termination);
+               break;
+       case STATUS_FORMAT_PORCELAIN:
+               wt_porcelain_print(&s, null_termination);
+               break;
+       case STATUS_FORMAT_LONG:
+               s.verbose = verbose;
+               wt_status_print(&s);
+               break;
+       }
+       return 0;
+ }
+ static void print_summary(const char *prefix, const unsigned char *sha1)
+ {
+       struct rev_info rev;
+       struct commit *commit;
+       struct strbuf format = STRBUF_INIT;
+       unsigned char junk_sha1[20];
+       const char *head = resolve_ref("HEAD", junk_sha1, 0, NULL);
+       struct pretty_print_context pctx = {0};
+       struct strbuf author_ident = STRBUF_INIT;
+       struct strbuf committer_ident = STRBUF_INIT;
+       commit = lookup_commit(sha1);
+       if (!commit)
+               die("couldn't look up newly created commit");
+       if (!commit || parse_commit(commit))
+               die("could not parse newly created commit");
+       strbuf_addstr(&format, "format:%h] %s");
+       format_commit_message(commit, "%an <%ae>", &author_ident, &pctx);
+       format_commit_message(commit, "%cn <%ce>", &committer_ident, &pctx);
+       if (strbuf_cmp(&author_ident, &committer_ident)) {
+               strbuf_addstr(&format, "\n Author: ");
+               strbuf_addbuf_percentquote(&format, &author_ident);
+       }
+       if (!user_ident_sufficiently_given()) {
+               strbuf_addstr(&format, "\n Committer: ");
+               strbuf_addbuf_percentquote(&format, &committer_ident);
+               if (advice_implicit_identity) {
+                       strbuf_addch(&format, '\n');
+                       strbuf_addstr(&format, implicit_ident_advice);
+               }
+       }
+       strbuf_release(&author_ident);
+       strbuf_release(&committer_ident);
+       init_revisions(&rev, prefix);
+       setup_revisions(0, NULL, &rev, NULL);
+       rev.abbrev = 0;
+       rev.diff = 1;
+       rev.diffopt.output_format =
+               DIFF_FORMAT_SHORTSTAT | DIFF_FORMAT_SUMMARY;
+       rev.verbose_header = 1;
+       rev.show_root_diff = 1;
+       get_commit_format(format.buf, &rev);
+       rev.always_show_header = 0;
+       rev.diffopt.detect_rename = 1;
+       rev.diffopt.rename_limit = 100;
+       rev.diffopt.break_opt = 0;
+       diff_setup_done(&rev.diffopt);
+       printf("[%s%s ",
+               !prefixcmp(head, "refs/heads/") ?
+                       head + 11 :
+                       !strcmp(head, "HEAD") ?
+                               "detached HEAD" :
+                               head,
+               initial_commit ? " (root-commit)" : "");
+       if (!log_tree_commit(&rev, commit)) {
+               struct pretty_print_context ctx = {0};
+               struct strbuf buf = STRBUF_INIT;
+               ctx.date_mode = DATE_NORMAL;
+               format_commit_message(commit, format.buf + 7, &buf, &ctx);
+               printf("%s\n", buf.buf);
+               strbuf_release(&buf);
+       }
+       strbuf_release(&format);
+ }
+ static int git_commit_config(const char *k, const char *v, void *cb)
+ {
+       struct wt_status *s = cb;
+       if (!strcmp(k, "commit.template"))
+               return git_config_pathname(&template_file, k, v);
+       if (!strcmp(k, "commit.status")) {
+               include_status = git_config_bool(k, v);
+               return 0;
+       }
+       return git_status_config(k, v, s);
+ }
+ int cmd_commit(int argc, const char **argv, const char *prefix)
+ {
+       struct strbuf sb = STRBUF_INIT;
+       const char *index_file, *reflog_msg;
+       char *nl, *p;
+       unsigned char commit_sha1[20];
+       struct ref_lock *ref_lock;
+       struct commit_list *parents = NULL, **pptr = &parents;
+       struct stat statbuf;
+       int allow_fast_forward = 1;
+       struct wt_status s;
+       wt_status_prepare(&s);
+       git_config(git_commit_config, &s);
+       in_merge = file_exists(git_path("MERGE_HEAD"));
+       s.in_merge = in_merge;
+       if (s.use_color == -1)
+               s.use_color = git_use_color_default;
+       argc = parse_and_validate_options(argc, argv, builtin_commit_usage,
+                                         prefix, &s);
+       if (dry_run) {
+               if (diff_use_color_default == -1)
+                       diff_use_color_default = git_use_color_default;
+               return dry_run_commit(argc, argv, prefix, &s);
+       }
+       index_file = prepare_index(argc, argv, prefix, 0);
+       /* Set up everything for writing the commit object.  This includes
+          running hooks, writing the trees, and interacting with the user.  */
+       if (!prepare_to_commit(index_file, prefix, &s)) {
+               rollback_index_files();
+               return 1;
+       }
+       /* Determine parents */
+       if (initial_commit) {
+               reflog_msg = "commit (initial)";
+       } else if (amend) {
+               struct commit_list *c;
+               struct commit *commit;
+               reflog_msg = "commit (amend)";
+               commit = lookup_commit(head_sha1);
+               if (!commit || parse_commit(commit))
+                       die("could not parse HEAD commit");
+               for (c = commit->parents; c; c = c->next)
+                       pptr = &commit_list_insert(c->item, pptr)->next;
+       } else if (in_merge) {
+               struct strbuf m = STRBUF_INIT;
+               FILE *fp;
+               reflog_msg = "commit (merge)";
+               pptr = &commit_list_insert(lookup_commit(head_sha1), pptr)->next;
+               fp = fopen(git_path("MERGE_HEAD"), "r");
+               if (fp == NULL)
+                       die_errno("could not open '%s' for reading",
+                                 git_path("MERGE_HEAD"));
+               while (strbuf_getline(&m, fp, '\n') != EOF) {
+                       unsigned char sha1[20];
+                       if (get_sha1_hex(m.buf, sha1) < 0)
+                               die("Corrupt MERGE_HEAD file (%s)", m.buf);
+                       pptr = &commit_list_insert(lookup_commit(sha1), pptr)->next;
+               }
+               fclose(fp);
+               strbuf_release(&m);
+               if (!stat(git_path("MERGE_MODE"), &statbuf)) {
+                       if (strbuf_read_file(&sb, git_path("MERGE_MODE"), 0) < 0)
+                               die_errno("could not read MERGE_MODE");
+                       if (!strcmp(sb.buf, "no-ff"))
+                               allow_fast_forward = 0;
+               }
+               if (allow_fast_forward)
+                       parents = reduce_heads(parents);
+       } else {
+               reflog_msg = "commit";
+               pptr = &commit_list_insert(lookup_commit(head_sha1), pptr)->next;
+       }
+       /* Finally, get the commit message */
+       strbuf_reset(&sb);
+       if (strbuf_read_file(&sb, git_path(commit_editmsg), 0) < 0) {
+               int saved_errno = errno;
+               rollback_index_files();
+               die("could not read commit message: %s", strerror(saved_errno));
+       }
+       /* Truncate the message just before the diff, if any. */
+       if (verbose) {
+               p = strstr(sb.buf, "\ndiff --git ");
+               if (p != NULL)
+                       strbuf_setlen(&sb, p - sb.buf + 1);
+       }
+       if (cleanup_mode != CLEANUP_NONE)
+               stripspace(&sb, cleanup_mode == CLEANUP_ALL);
+       if (message_is_empty(&sb)) {
+               rollback_index_files();
+               fprintf(stderr, "Aborting commit due to empty commit message.\n");
+               exit(1);
+       }
+       if (commit_tree(sb.buf, active_cache_tree->sha1, parents, commit_sha1,
+                       fmt_ident(author_name, author_email, author_date,
+                               IDENT_ERROR_ON_NO_NAME))) {
+               rollback_index_files();
+               die("failed to write commit object");
+       }
+       ref_lock = lock_any_ref_for_update("HEAD",
+                                          initial_commit ? NULL : head_sha1,
+                                          0);
+       nl = strchr(sb.buf, '\n');
+       if (nl)
+               strbuf_setlen(&sb, nl + 1 - sb.buf);
+       else
+               strbuf_addch(&sb, '\n');
+       strbuf_insert(&sb, 0, reflog_msg, strlen(reflog_msg));
+       strbuf_insert(&sb, strlen(reflog_msg), ": ", 2);
+       if (!ref_lock) {
+               rollback_index_files();
+               die("cannot lock HEAD ref");
+       }
+       if (write_ref_sha1(ref_lock, commit_sha1, sb.buf) < 0) {
+               rollback_index_files();
+               die("cannot update HEAD ref");
+       }
+       unlink(git_path("MERGE_HEAD"));
+       unlink(git_path("MERGE_MSG"));
+       unlink(git_path("MERGE_MODE"));
+       unlink(git_path("SQUASH_MSG"));
+       if (commit_index_files())
+               die ("Repository has been updated, but unable to write\n"
+                    "new_index file. Check that disk is not full or quota is\n"
+                    "not exceeded, and then \"git reset HEAD\" to recover.");
+       rerere(0);
+       run_hook(get_index_file(), "post-commit", NULL);
+       if (!quiet)
+               print_summary(prefix, commit_sha1);
+       return 0;
+ }
diff --cc builtin/merge.c
index 0000000000000000000000000000000000000000,3aaec7bed76af9efdfe5647be0da64373db2011e..c6e3e7fdaf92dc94925283ee5470588625c7df48
mode 000000,100644..100644
--- /dev/null
@@@ -1,0 -1,1292 +1,1292 @@@
 -static struct strbuf merge_msg;
+ /*
+  * Builtin "git merge"
+  *
+  * Copyright (c) 2008 Miklos Vajna <vmiklos@frugalware.org>
+  *
+  * Based on git-merge.sh by Junio C Hamano.
+  */
+ #include "cache.h"
+ #include "parse-options.h"
+ #include "builtin.h"
+ #include "run-command.h"
+ #include "diff.h"
+ #include "refs.h"
+ #include "commit.h"
+ #include "diffcore.h"
+ #include "revision.h"
+ #include "unpack-trees.h"
+ #include "cache-tree.h"
+ #include "dir.h"
+ #include "utf8.h"
+ #include "log-tree.h"
+ #include "color.h"
+ #include "rerere.h"
+ #include "help.h"
+ #include "merge-recursive.h"
+ #include "resolve-undo.h"
+ #define DEFAULT_TWOHEAD (1<<0)
+ #define DEFAULT_OCTOPUS (1<<1)
+ #define NO_FAST_FORWARD (1<<2)
+ #define NO_TRIVIAL      (1<<3)
+ struct strategy {
+       const char *name;
+       unsigned attr;
+ };
+ static const char * const builtin_merge_usage[] = {
+       "git merge [options] <remote>...",
+       "git merge [options] <msg> HEAD <remote>",
+       NULL
+ };
+ static int show_diffstat = 1, option_log, squash;
+ static int option_commit = 1, allow_fast_forward = 1;
+ static int fast_forward_only;
+ static int allow_trivial = 1, have_message;
++static struct strbuf merge_msg = STRBUF_INIT;
+ static struct commit_list *remoteheads;
+ static unsigned char head[20], stash[20];
+ static struct strategy **use_strategies;
+ static size_t use_strategies_nr, use_strategies_alloc;
+ static const char **xopts;
+ static size_t xopts_nr, xopts_alloc;
+ static const char *branch;
+ static int verbosity;
+ static int allow_rerere_auto;
+ static struct strategy all_strategy[] = {
+       { "recursive",  DEFAULT_TWOHEAD | NO_TRIVIAL },
+       { "octopus",    DEFAULT_OCTOPUS },
+       { "resolve",    0 },
+       { "ours",       NO_FAST_FORWARD | NO_TRIVIAL },
+       { "subtree",    NO_FAST_FORWARD | NO_TRIVIAL },
+ };
+ static const char *pull_twohead, *pull_octopus;
+ static int option_parse_message(const struct option *opt,
+                               const char *arg, int unset)
+ {
+       struct strbuf *buf = opt->value;
+       if (unset)
+               strbuf_setlen(buf, 0);
+       else if (arg) {
+               strbuf_addf(buf, "%s%s", buf->len ? "\n\n" : "", arg);
+               have_message = 1;
+       } else
+               return error("switch `m' requires a value");
+       return 0;
+ }
+ static struct strategy *get_strategy(const char *name)
+ {
+       int i;
+       struct strategy *ret;
+       static struct cmdnames main_cmds, other_cmds;
+       static int loaded;
+       if (!name)
+               return NULL;
+       for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
+               if (!strcmp(name, all_strategy[i].name))
+                       return &all_strategy[i];
+       if (!loaded) {
+               struct cmdnames not_strategies;
+               loaded = 1;
+               memset(&not_strategies, 0, sizeof(struct cmdnames));
+               load_command_list("git-merge-", &main_cmds, &other_cmds);
+               for (i = 0; i < main_cmds.cnt; i++) {
+                       int j, found = 0;
+                       struct cmdname *ent = main_cmds.names[i];
+                       for (j = 0; j < ARRAY_SIZE(all_strategy); j++)
+                               if (!strncmp(ent->name, all_strategy[j].name, ent->len)
+                                               && !all_strategy[j].name[ent->len])
+                                       found = 1;
+                       if (!found)
+                               add_cmdname(&not_strategies, ent->name, ent->len);
+               }
+               exclude_cmds(&main_cmds, &not_strategies);
+       }
+       if (!is_in_cmdlist(&main_cmds, name) && !is_in_cmdlist(&other_cmds, name)) {
+               fprintf(stderr, "Could not find merge strategy '%s'.\n", name);
+               fprintf(stderr, "Available strategies are:");
+               for (i = 0; i < main_cmds.cnt; i++)
+                       fprintf(stderr, " %s", main_cmds.names[i]->name);
+               fprintf(stderr, ".\n");
+               if (other_cmds.cnt) {
+                       fprintf(stderr, "Available custom strategies are:");
+                       for (i = 0; i < other_cmds.cnt; i++)
+                               fprintf(stderr, " %s", other_cmds.names[i]->name);
+                       fprintf(stderr, ".\n");
+               }
+               exit(1);
+       }
+       ret = xcalloc(1, sizeof(struct strategy));
+       ret->name = xstrdup(name);
+       return ret;
+ }
+ static void append_strategy(struct strategy *s)
+ {
+       ALLOC_GROW(use_strategies, use_strategies_nr + 1, use_strategies_alloc);
+       use_strategies[use_strategies_nr++] = s;
+ }
+ static int option_parse_strategy(const struct option *opt,
+                                const char *name, int unset)
+ {
+       if (unset)
+               return 0;
+       append_strategy(get_strategy(name));
+       return 0;
+ }
+ static int option_parse_x(const struct option *opt,
+                         const char *arg, int unset)
+ {
+       if (unset)
+               return 0;
+       ALLOC_GROW(xopts, xopts_nr + 1, xopts_alloc);
+       xopts[xopts_nr++] = xstrdup(arg);
+       return 0;
+ }
+ static int option_parse_n(const struct option *opt,
+                         const char *arg, int unset)
+ {
+       show_diffstat = unset;
+       return 0;
+ }
+ static struct option builtin_merge_options[] = {
+       { OPTION_CALLBACK, 'n', NULL, NULL, NULL,
+               "do not show a diffstat at the end of the merge",
+               PARSE_OPT_NOARG, option_parse_n },
+       OPT_BOOLEAN(0, "stat", &show_diffstat,
+               "show a diffstat at the end of the merge"),
+       OPT_BOOLEAN(0, "summary", &show_diffstat, "(synonym to --stat)"),
+       OPT_BOOLEAN(0, "log", &option_log,
+               "add list of one-line log to merge commit message"),
+       OPT_BOOLEAN(0, "squash", &squash,
+               "create a single commit instead of doing a merge"),
+       OPT_BOOLEAN(0, "commit", &option_commit,
+               "perform a commit if the merge succeeds (default)"),
+       OPT_BOOLEAN(0, "ff", &allow_fast_forward,
+               "allow fast-forward (default)"),
+       OPT_BOOLEAN(0, "ff-only", &fast_forward_only,
+               "abort if fast-forward is not possible"),
+       OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
+       OPT_CALLBACK('s', "strategy", &use_strategies, "strategy",
+               "merge strategy to use", option_parse_strategy),
+       OPT_CALLBACK('X', "strategy-option", &xopts, "option=value",
+               "option for selected merge strategy", option_parse_x),
+       OPT_CALLBACK('m', "message", &merge_msg, "message",
+               "message to be used for the merge commit (if any)",
+               option_parse_message),
+       OPT__VERBOSITY(&verbosity),
+       OPT_END()
+ };
+ /* Cleans up metadata that is uninteresting after a succeeded merge. */
+ static void drop_save(void)
+ {
+       unlink(git_path("MERGE_HEAD"));
+       unlink(git_path("MERGE_MSG"));
+       unlink(git_path("MERGE_MODE"));
+ }
+ static void save_state(void)
+ {
+       int len;
+       struct child_process cp;
+       struct strbuf buffer = STRBUF_INIT;
+       const char *argv[] = {"stash", "create", NULL};
+       memset(&cp, 0, sizeof(cp));
+       cp.argv = argv;
+       cp.out = -1;
+       cp.git_cmd = 1;
+       if (start_command(&cp))
+               die("could not run stash.");
+       len = strbuf_read(&buffer, cp.out, 1024);
+       close(cp.out);
+       if (finish_command(&cp) || len < 0)
+               die("stash failed");
+       else if (!len)
+               return;
+       strbuf_setlen(&buffer, buffer.len-1);
+       if (get_sha1(buffer.buf, stash))
+               die("not a valid object: %s", buffer.buf);
+ }
+ static void reset_hard(unsigned const char *sha1, int verbose)
+ {
+       int i = 0;
+       const char *args[6];
+       args[i++] = "read-tree";
+       if (verbose)
+               args[i++] = "-v";
+       args[i++] = "--reset";
+       args[i++] = "-u";
+       args[i++] = sha1_to_hex(sha1);
+       args[i] = NULL;
+       if (run_command_v_opt(args, RUN_GIT_CMD))
+               die("read-tree failed");
+ }
+ static void restore_state(void)
+ {
+       struct strbuf sb = STRBUF_INIT;
+       const char *args[] = { "stash", "apply", NULL, NULL };
+       if (is_null_sha1(stash))
+               return;
+       reset_hard(head, 1);
+       args[2] = sha1_to_hex(stash);
+       /*
+        * It is OK to ignore error here, for example when there was
+        * nothing to restore.
+        */
+       run_command_v_opt(args, RUN_GIT_CMD);
+       strbuf_release(&sb);
+       refresh_cache(REFRESH_QUIET);
+ }
+ /* This is called when no merge was necessary. */
+ static void finish_up_to_date(const char *msg)
+ {
+       if (verbosity >= 0)
+               printf("%s%s\n", squash ? " (nothing to squash)" : "", msg);
+       drop_save();
+ }
+ static void squash_message(void)
+ {
+       struct rev_info rev;
+       struct commit *commit;
+       struct strbuf out = STRBUF_INIT;
+       struct commit_list *j;
+       int fd;
+       struct pretty_print_context ctx = {0};
+       printf("Squash commit -- not updating HEAD\n");
+       fd = open(git_path("SQUASH_MSG"), O_WRONLY | O_CREAT, 0666);
+       if (fd < 0)
+               die_errno("Could not write to '%s'", git_path("SQUASH_MSG"));
+       init_revisions(&rev, NULL);
+       rev.ignore_merges = 1;
+       rev.commit_format = CMIT_FMT_MEDIUM;
+       commit = lookup_commit(head);
+       commit->object.flags |= UNINTERESTING;
+       add_pending_object(&rev, &commit->object, NULL);
+       for (j = remoteheads; j; j = j->next)
+               add_pending_object(&rev, &j->item->object, NULL);
+       setup_revisions(0, NULL, &rev, NULL);
+       if (prepare_revision_walk(&rev))
+               die("revision walk setup failed");
+       ctx.abbrev = rev.abbrev;
+       ctx.date_mode = rev.date_mode;
+       strbuf_addstr(&out, "Squashed commit of the following:\n");
+       while ((commit = get_revision(&rev)) != NULL) {
+               strbuf_addch(&out, '\n');
+               strbuf_addf(&out, "commit %s\n",
+                       sha1_to_hex(commit->object.sha1));
+               pretty_print_commit(rev.commit_format, commit, &out, &ctx);
+       }
+       if (write(fd, out.buf, out.len) < 0)
+               die_errno("Writing SQUASH_MSG");
+       if (close(fd))
+               die_errno("Finishing SQUASH_MSG");
+       strbuf_release(&out);
+ }
+ static void finish(const unsigned char *new_head, const char *msg)
+ {
+       struct strbuf reflog_message = STRBUF_INIT;
+       if (!msg)
+               strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
+       else {
+               if (verbosity >= 0)
+                       printf("%s\n", msg);
+               strbuf_addf(&reflog_message, "%s: %s",
+                       getenv("GIT_REFLOG_ACTION"), msg);
+       }
+       if (squash) {
+               squash_message();
+       } else {
+               if (verbosity >= 0 && !merge_msg.len)
+                       printf("No merge message -- not updating HEAD\n");
+               else {
+                       const char *argv_gc_auto[] = { "gc", "--auto", NULL };
+                       update_ref(reflog_message.buf, "HEAD",
+                               new_head, head, 0,
+                               DIE_ON_ERR);
+                       /*
+                        * We ignore errors in 'gc --auto', since the
+                        * user should see them.
+                        */
+                       run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
+               }
+       }
+       if (new_head && show_diffstat) {
+               struct diff_options opts;
+               diff_setup(&opts);
+               opts.output_format |=
+                       DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
+               opts.detect_rename = DIFF_DETECT_RENAME;
+               if (diff_use_color_default > 0)
+                       DIFF_OPT_SET(&opts, COLOR_DIFF);
+               if (diff_setup_done(&opts) < 0)
+                       die("diff_setup_done failed");
+               diff_tree_sha1(head, new_head, "", &opts);
+               diffcore_std(&opts);
+               diff_flush(&opts);
+       }
+       /* Run a post-merge hook */
+       run_hook(NULL, "post-merge", squash ? "1" : "0", NULL);
+       strbuf_release(&reflog_message);
+ }
+ /* Get the name for the merge commit's message. */
+ static void merge_name(const char *remote, struct strbuf *msg)
+ {
+       struct object *remote_head;
+       unsigned char branch_head[20], buf_sha[20];
+       struct strbuf buf = STRBUF_INIT;
+       struct strbuf bname = STRBUF_INIT;
+       const char *ptr;
+       char *found_ref;
+       int len, early;
+       strbuf_branchname(&bname, remote);
+       remote = bname.buf;
+       memset(branch_head, 0, sizeof(branch_head));
+       remote_head = peel_to_type(remote, 0, NULL, OBJ_COMMIT);
+       if (!remote_head)
+               die("'%s' does not point to a commit", remote);
+       if (dwim_ref(remote, strlen(remote), branch_head, &found_ref) > 0) {
+               if (!prefixcmp(found_ref, "refs/heads/")) {
+                       strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
+                                   sha1_to_hex(branch_head), remote);
+                       goto cleanup;
+               }
+               if (!prefixcmp(found_ref, "refs/remotes/")) {
+                       strbuf_addf(msg, "%s\t\tremote branch '%s' of .\n",
+                                   sha1_to_hex(branch_head), remote);
+                       goto cleanup;
+               }
+       }
+       /* See if remote matches <name>^^^.. or <name>~<number> */
+       for (len = 0, ptr = remote + strlen(remote);
+            remote < ptr && ptr[-1] == '^';
+            ptr--)
+               len++;
+       if (len)
+               early = 1;
+       else {
+               early = 0;
+               ptr = strrchr(remote, '~');
+               if (ptr) {
+                       int seen_nonzero = 0;
+                       len++; /* count ~ */
+                       while (*++ptr && isdigit(*ptr)) {
+                               seen_nonzero |= (*ptr != '0');
+                               len++;
+                       }
+                       if (*ptr)
+                               len = 0; /* not ...~<number> */
+                       else if (seen_nonzero)
+                               early = 1;
+                       else if (len == 1)
+                               early = 1; /* "name~" is "name~1"! */
+               }
+       }
+       if (len) {
+               struct strbuf truname = STRBUF_INIT;
+               strbuf_addstr(&truname, "refs/heads/");
+               strbuf_addstr(&truname, remote);
+               strbuf_setlen(&truname, truname.len - len);
+               if (resolve_ref(truname.buf, buf_sha, 0, NULL)) {
+                       strbuf_addf(msg,
+                                   "%s\t\tbranch '%s'%s of .\n",
+                                   sha1_to_hex(remote_head->sha1),
+                                   truname.buf + 11,
+                                   (early ? " (early part)" : ""));
+                       strbuf_release(&truname);
+                       goto cleanup;
+               }
+       }
+       if (!strcmp(remote, "FETCH_HEAD") &&
+                       !access(git_path("FETCH_HEAD"), R_OK)) {
+               FILE *fp;
+               struct strbuf line = STRBUF_INIT;
+               char *ptr;
+               fp = fopen(git_path("FETCH_HEAD"), "r");
+               if (!fp)
+                       die_errno("could not open '%s' for reading",
+                                 git_path("FETCH_HEAD"));
+               strbuf_getline(&line, fp, '\n');
+               fclose(fp);
+               ptr = strstr(line.buf, "\tnot-for-merge\t");
+               if (ptr)
+                       strbuf_remove(&line, ptr-line.buf+1, 13);
+               strbuf_addbuf(msg, &line);
+               strbuf_release(&line);
+               goto cleanup;
+       }
+       strbuf_addf(msg, "%s\t\tcommit '%s'\n",
+               sha1_to_hex(remote_head->sha1), remote);
+ cleanup:
+       strbuf_release(&buf);
+       strbuf_release(&bname);
+ }
+ static int git_merge_config(const char *k, const char *v, void *cb)
+ {
+       if (branch && !prefixcmp(k, "branch.") &&
+               !prefixcmp(k + 7, branch) &&
+               !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
+               const char **argv;
+               int argc;
+               char *buf;
+               buf = xstrdup(v);
+               argc = split_cmdline(buf, &argv);
+               if (argc < 0)
+                       die("Bad branch.%s.mergeoptions string", branch);
+               argv = xrealloc(argv, sizeof(*argv) * (argc + 2));
+               memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
+               argc++;
+               parse_options(argc, argv, NULL, builtin_merge_options,
+                             builtin_merge_usage, 0);
+               free(buf);
+       }
+       if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
+               show_diffstat = git_config_bool(k, v);
+       else if (!strcmp(k, "pull.twohead"))
+               return git_config_string(&pull_twohead, k, v);
+       else if (!strcmp(k, "pull.octopus"))
+               return git_config_string(&pull_octopus, k, v);
+       else if (!strcmp(k, "merge.log") || !strcmp(k, "merge.summary"))
+               option_log = git_config_bool(k, v);
+       return git_diff_ui_config(k, v, cb);
+ }
+ static int read_tree_trivial(unsigned char *common, unsigned char *head,
+                            unsigned char *one)
+ {
+       int i, nr_trees = 0;
+       struct tree *trees[MAX_UNPACK_TREES];
+       struct tree_desc t[MAX_UNPACK_TREES];
+       struct unpack_trees_options opts;
+       memset(&opts, 0, sizeof(opts));
+       opts.head_idx = 2;
+       opts.src_index = &the_index;
+       opts.dst_index = &the_index;
+       opts.update = 1;
+       opts.verbose_update = 1;
+       opts.trivial_merges_only = 1;
+       opts.merge = 1;
+       trees[nr_trees] = parse_tree_indirect(common);
+       if (!trees[nr_trees++])
+               return -1;
+       trees[nr_trees] = parse_tree_indirect(head);
+       if (!trees[nr_trees++])
+               return -1;
+       trees[nr_trees] = parse_tree_indirect(one);
+       if (!trees[nr_trees++])
+               return -1;
+       opts.fn = threeway_merge;
+       cache_tree_free(&active_cache_tree);
+       for (i = 0; i < nr_trees; i++) {
+               parse_tree(trees[i]);
+               init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
+       }
+       if (unpack_trees(nr_trees, t, &opts))
+               return -1;
+       return 0;
+ }
+ static void write_tree_trivial(unsigned char *sha1)
+ {
+       if (write_cache_as_tree(sha1, 0, NULL))
+               die("git write-tree failed to write a tree");
+ }
+ static int try_merge_strategy(const char *strategy, struct commit_list *common,
+                             const char *head_arg)
+ {
+       const char **args;
+       int i = 0, x = 0, ret;
+       struct commit_list *j;
+       struct strbuf buf = STRBUF_INIT;
+       int index_fd;
+       struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
+       index_fd = hold_locked_index(lock, 1);
+       refresh_cache(REFRESH_QUIET);
+       if (active_cache_changed &&
+                       (write_cache(index_fd, active_cache, active_nr) ||
+                        commit_locked_index(lock)))
+               return error("Unable to write index.");
+       rollback_lock_file(lock);
+       if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
+               int clean;
+               struct commit *result;
+               struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
+               int index_fd;
+               struct commit_list *reversed = NULL;
+               struct merge_options o;
+               if (remoteheads->next) {
+                       error("Not handling anything other than two heads merge.");
+                       return 2;
+               }
+               init_merge_options(&o);
+               if (!strcmp(strategy, "subtree"))
+                       o.subtree_shift = "";
+               for (x = 0; x < xopts_nr; x++) {
+                       if (!strcmp(xopts[x], "ours"))
+                               o.recursive_variant = MERGE_RECURSIVE_OURS;
+                       else if (!strcmp(xopts[x], "theirs"))
+                               o.recursive_variant = MERGE_RECURSIVE_THEIRS;
+                       else if (!strcmp(xopts[x], "subtree"))
+                               o.subtree_shift = "";
+                       else if (!prefixcmp(xopts[x], "subtree="))
+                               o.subtree_shift = xopts[x]+8;
+                       else
+                               die("Unknown option for merge-recursive: -X%s", xopts[x]);
+               }
+               o.branch1 = head_arg;
+               o.branch2 = remoteheads->item->util;
+               for (j = common; j; j = j->next)
+                       commit_list_insert(j->item, &reversed);
+               index_fd = hold_locked_index(lock, 1);
+               clean = merge_recursive(&o, lookup_commit(head),
+                               remoteheads->item, reversed, &result);
+               if (active_cache_changed &&
+                               (write_cache(index_fd, active_cache, active_nr) ||
+                                commit_locked_index(lock)))
+                       die ("unable to write %s", get_index_file());
+               rollback_lock_file(lock);
+               return clean ? 0 : 1;
+       } else {
+               args = xmalloc((4 + xopts_nr + commit_list_count(common) +
+                                       commit_list_count(remoteheads)) * sizeof(char *));
+               strbuf_addf(&buf, "merge-%s", strategy);
+               args[i++] = buf.buf;
+               for (x = 0; x < xopts_nr; x++) {
+                       char *s = xmalloc(strlen(xopts[x])+2+1);
+                       strcpy(s, "--");
+                       strcpy(s+2, xopts[x]);
+                       args[i++] = s;
+               }
+               for (j = common; j; j = j->next)
+                       args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
+               args[i++] = "--";
+               args[i++] = head_arg;
+               for (j = remoteheads; j; j = j->next)
+                       args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
+               args[i] = NULL;
+               ret = run_command_v_opt(args, RUN_GIT_CMD);
+               strbuf_release(&buf);
+               i = 1;
+               for (x = 0; x < xopts_nr; x++)
+                       free((void *)args[i++]);
+               for (j = common; j; j = j->next)
+                       free((void *)args[i++]);
+               i += 2;
+               for (j = remoteheads; j; j = j->next)
+                       free((void *)args[i++]);
+               free(args);
+               discard_cache();
+               if (read_cache() < 0)
+                       die("failed to read the cache");
+               resolve_undo_clear();
+               return ret;
+       }
+ }
+ static void count_diff_files(struct diff_queue_struct *q,
+                            struct diff_options *opt, void *data)
+ {
+       int *count = data;
+       (*count) += q->nr;
+ }
+ static int count_unmerged_entries(void)
+ {
+       int i, ret = 0;
+       for (i = 0; i < active_nr; i++)
+               if (ce_stage(active_cache[i]))
+                       ret++;
+       return ret;
+ }
+ static int checkout_fast_forward(unsigned char *head, unsigned char *remote)
+ {
+       struct tree *trees[MAX_UNPACK_TREES];
+       struct unpack_trees_options opts;
+       struct tree_desc t[MAX_UNPACK_TREES];
+       int i, fd, nr_trees = 0;
+       struct dir_struct dir;
+       struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
+       refresh_cache(REFRESH_QUIET);
+       fd = hold_locked_index(lock_file, 1);
+       memset(&trees, 0, sizeof(trees));
+       memset(&opts, 0, sizeof(opts));
+       memset(&t, 0, sizeof(t));
+       memset(&dir, 0, sizeof(dir));
+       dir.flags |= DIR_SHOW_IGNORED;
+       dir.exclude_per_dir = ".gitignore";
+       opts.dir = &dir;
+       opts.head_idx = 1;
+       opts.src_index = &the_index;
+       opts.dst_index = &the_index;
+       opts.update = 1;
+       opts.verbose_update = 1;
+       opts.merge = 1;
+       opts.fn = twoway_merge;
+       opts.msgs = get_porcelain_error_msgs();
+       trees[nr_trees] = parse_tree_indirect(head);
+       if (!trees[nr_trees++])
+               return -1;
+       trees[nr_trees] = parse_tree_indirect(remote);
+       if (!trees[nr_trees++])
+               return -1;
+       for (i = 0; i < nr_trees; i++) {
+               parse_tree(trees[i]);
+               init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
+       }
+       if (unpack_trees(nr_trees, t, &opts))
+               return -1;
+       if (write_cache(fd, active_cache, active_nr) ||
+               commit_locked_index(lock_file))
+               die("unable to write new index file");
+       return 0;
+ }
+ static void split_merge_strategies(const char *string, struct strategy **list,
+                                  int *nr, int *alloc)
+ {
+       char *p, *q, *buf;
+       if (!string)
+               return;
+       buf = xstrdup(string);
+       q = buf;
+       for (;;) {
+               p = strchr(q, ' ');
+               if (!p) {
+                       ALLOC_GROW(*list, *nr + 1, *alloc);
+                       (*list)[(*nr)++].name = xstrdup(q);
+                       free(buf);
+                       return;
+               } else {
+                       *p = '\0';
+                       ALLOC_GROW(*list, *nr + 1, *alloc);
+                       (*list)[(*nr)++].name = xstrdup(q);
+                       q = ++p;
+               }
+       }
+ }
+ static void add_strategies(const char *string, unsigned attr)
+ {
+       struct strategy *list = NULL;
+       int list_alloc = 0, list_nr = 0, i;
+       memset(&list, 0, sizeof(list));
+       split_merge_strategies(string, &list, &list_nr, &list_alloc);
+       if (list) {
+               for (i = 0; i < list_nr; i++)
+                       append_strategy(get_strategy(list[i].name));
+               return;
+       }
+       for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
+               if (all_strategy[i].attr & attr)
+                       append_strategy(&all_strategy[i]);
+ }
+ static int merge_trivial(void)
+ {
+       unsigned char result_tree[20], result_commit[20];
+       struct commit_list *parent = xmalloc(sizeof(*parent));
+       write_tree_trivial(result_tree);
+       printf("Wonderful.\n");
+       parent->item = lookup_commit(head);
+       parent->next = xmalloc(sizeof(*parent->next));
+       parent->next->item = remoteheads->item;
+       parent->next->next = NULL;
+       commit_tree(merge_msg.buf, result_tree, parent, result_commit, NULL);
+       finish(result_commit, "In-index merge");
+       drop_save();
+       return 0;
+ }
+ static int finish_automerge(struct commit_list *common,
+                           unsigned char *result_tree,
+                           const char *wt_strategy)
+ {
+       struct commit_list *parents = NULL, *j;
+       struct strbuf buf = STRBUF_INIT;
+       unsigned char result_commit[20];
+       free_commit_list(common);
+       if (allow_fast_forward) {
+               parents = remoteheads;
+               commit_list_insert(lookup_commit(head), &parents);
+               parents = reduce_heads(parents);
+       } else {
+               struct commit_list **pptr = &parents;
+               pptr = &commit_list_insert(lookup_commit(head),
+                               pptr)->next;
+               for (j = remoteheads; j; j = j->next)
+                       pptr = &commit_list_insert(j->item, pptr)->next;
+       }
+       free_commit_list(remoteheads);
+       strbuf_addch(&merge_msg, '\n');
+       commit_tree(merge_msg.buf, result_tree, parents, result_commit, NULL);
+       strbuf_addf(&buf, "Merge made by %s.", wt_strategy);
+       finish(result_commit, buf.buf);
+       strbuf_release(&buf);
+       drop_save();
+       return 0;
+ }
+ static int suggest_conflicts(void)
+ {
+       FILE *fp;
+       int pos;
+       fp = fopen(git_path("MERGE_MSG"), "a");
+       if (!fp)
+               die_errno("Could not open '%s' for writing",
+                         git_path("MERGE_MSG"));
+       fprintf(fp, "\nConflicts:\n");
+       for (pos = 0; pos < active_nr; pos++) {
+               struct cache_entry *ce = active_cache[pos];
+               if (ce_stage(ce)) {
+                       fprintf(fp, "\t%s\n", ce->name);
+                       while (pos + 1 < active_nr &&
+                                       !strcmp(ce->name,
+                                               active_cache[pos + 1]->name))
+                               pos++;
+               }
+       }
+       fclose(fp);
+       rerere(allow_rerere_auto);
+       printf("Automatic merge failed; "
+                       "fix conflicts and then commit the result.\n");
+       return 1;
+ }
+ static struct commit *is_old_style_invocation(int argc, const char **argv)
+ {
+       struct commit *second_token = NULL;
+       if (argc > 2) {
+               unsigned char second_sha1[20];
+               if (get_sha1(argv[1], second_sha1))
+                       return NULL;
+               second_token = lookup_commit_reference_gently(second_sha1, 0);
+               if (!second_token)
+                       die("'%s' is not a commit", argv[1]);
+               if (hashcmp(second_token->object.sha1, head))
+                       return NULL;
+       }
+       return second_token;
+ }
+ static int evaluate_result(void)
+ {
+       int cnt = 0;
+       struct rev_info rev;
+       /* Check how many files differ. */
+       init_revisions(&rev, "");
+       setup_revisions(0, NULL, &rev, NULL);
+       rev.diffopt.output_format |=
+               DIFF_FORMAT_CALLBACK;
+       rev.diffopt.format_callback = count_diff_files;
+       rev.diffopt.format_callback_data = &cnt;
+       run_diff_files(&rev, 0);
+       /*
+        * Check how many unmerged entries are
+        * there.
+        */
+       cnt += count_unmerged_entries();
+       return cnt;
+ }
+ int cmd_merge(int argc, const char **argv, const char *prefix)
+ {
+       unsigned char result_tree[20];
+       struct strbuf buf = STRBUF_INIT;
+       const char *head_arg;
+       int flag, head_invalid = 0, i;
+       int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
+       struct commit_list *common = NULL;
+       const char *best_strategy = NULL, *wt_strategy = NULL;
+       struct commit_list **remotes = &remoteheads;
+       if (read_cache_unmerged()) {
+               die_resolve_conflict("merge");
+       }
+       if (file_exists(git_path("MERGE_HEAD"))) {
+               /*
+                * There is no unmerged entry, don't advise 'git
+                * add/rm <file>', just 'git commit'.
+                */
+               if (advice_resolve_conflict)
+                       die("You have not concluded your merge (MERGE_HEAD exists).\n"
+                           "Please, commit your changes before you can merge.");
+               else
+                       die("You have not concluded your merge (MERGE_HEAD exists).");
+       }
+       resolve_undo_clear();
+       /*
+        * Check if we are _not_ on a detached HEAD, i.e. if there is a
+        * current branch.
+        */
+       branch = resolve_ref("HEAD", head, 0, &flag);
+       if (branch && !prefixcmp(branch, "refs/heads/"))
+               branch += 11;
+       if (is_null_sha1(head))
+               head_invalid = 1;
+       git_config(git_merge_config, NULL);
+       /* for color.ui */
+       if (diff_use_color_default == -1)
+               diff_use_color_default = git_use_color_default;
+       argc = parse_options(argc, argv, prefix, builtin_merge_options,
+                       builtin_merge_usage, 0);
+       if (verbosity < 0)
+               show_diffstat = 0;
+       if (squash) {
+               if (!allow_fast_forward)
+                       die("You cannot combine --squash with --no-ff.");
+               option_commit = 0;
+       }
+       if (!allow_fast_forward && fast_forward_only)
+               die("You cannot combine --no-ff with --ff-only.");
+       if (!argc)
+               usage_with_options(builtin_merge_usage,
+                       builtin_merge_options);
+       /*
+        * This could be traditional "merge <msg> HEAD <commit>..."  and
+        * the way we can tell it is to see if the second token is HEAD,
+        * but some people might have misused the interface and used a
+        * committish that is the same as HEAD there instead.
+        * Traditional format never would have "-m" so it is an
+        * additional safety measure to check for it.
+        */
+       if (!have_message && is_old_style_invocation(argc, argv)) {
+               strbuf_addstr(&merge_msg, argv[0]);
+               head_arg = argv[1];
+               argv += 2;
+               argc -= 2;
+       } else if (head_invalid) {
+               struct object *remote_head;
+               /*
+                * If the merged head is a valid one there is no reason
+                * to forbid "git merge" into a branch yet to be born.
+                * We do the same for "git pull".
+                */
+               if (argc != 1)
+                       die("Can merge only exactly one commit into "
+                               "empty head");
+               if (squash)
+                       die("Squash commit into empty head not supported yet");
+               if (!allow_fast_forward)
+                       die("Non-fast-forward commit does not make sense into "
+                           "an empty head");
+               remote_head = peel_to_type(argv[0], 0, NULL, OBJ_COMMIT);
+               if (!remote_head)
+                       die("%s - not something we can merge", argv[0]);
+               update_ref("initial pull", "HEAD", remote_head->sha1, NULL, 0,
+                               DIE_ON_ERR);
+               reset_hard(remote_head->sha1, 0);
+               return 0;
+       } else {
+               struct strbuf msg = STRBUF_INIT;
+               /* We are invoked directly as the first-class UI. */
+               head_arg = "HEAD";
+               /*
+                * All the rest are the commits being merged;
+                * prepare the standard merge summary message to
+                * be appended to the given message.  If remote
+                * is invalid we will die later in the common
+                * codepath so we discard the error in this
+                * loop.
+                */
+               if (!have_message) {
+                       for (i = 0; i < argc; i++)
+                               merge_name(argv[i], &msg);
+                       fmt_merge_msg(option_log, &msg, &merge_msg);
+                       if (merge_msg.len)
+                               strbuf_setlen(&merge_msg, merge_msg.len-1);
+               }
+       }
+       if (head_invalid || !argc)
+               usage_with_options(builtin_merge_usage,
+                       builtin_merge_options);
+       strbuf_addstr(&buf, "merge");
+       for (i = 0; i < argc; i++)
+               strbuf_addf(&buf, " %s", argv[i]);
+       setenv("GIT_REFLOG_ACTION", buf.buf, 0);
+       strbuf_reset(&buf);
+       for (i = 0; i < argc; i++) {
+               struct object *o;
+               struct commit *commit;
+               o = peel_to_type(argv[i], 0, NULL, OBJ_COMMIT);
+               if (!o)
+                       die("%s - not something we can merge", argv[i]);
+               commit = lookup_commit(o->sha1);
+               commit->util = (void *)argv[i];
+               remotes = &commit_list_insert(commit, remotes)->next;
+               strbuf_addf(&buf, "GITHEAD_%s", sha1_to_hex(o->sha1));
+               setenv(buf.buf, argv[i], 1);
+               strbuf_reset(&buf);
+       }
+       if (!use_strategies) {
+               if (!remoteheads->next)
+                       add_strategies(pull_twohead, DEFAULT_TWOHEAD);
+               else
+                       add_strategies(pull_octopus, DEFAULT_OCTOPUS);
+       }
+       for (i = 0; i < use_strategies_nr; i++) {
+               if (use_strategies[i]->attr & NO_FAST_FORWARD)
+                       allow_fast_forward = 0;
+               if (use_strategies[i]->attr & NO_TRIVIAL)
+                       allow_trivial = 0;
+       }
+       if (!remoteheads->next)
+               common = get_merge_bases(lookup_commit(head),
+                               remoteheads->item, 1);
+       else {
+               struct commit_list *list = remoteheads;
+               commit_list_insert(lookup_commit(head), &list);
+               common = get_octopus_merge_bases(list);
+               free(list);
+       }
+       update_ref("updating ORIG_HEAD", "ORIG_HEAD", head, NULL, 0,
+               DIE_ON_ERR);
+       if (!common)
+               ; /* No common ancestors found. We need a real merge. */
+       else if (!remoteheads->next && !common->next &&
+                       common->item == remoteheads->item) {
+               /*
+                * If head can reach all the merge then we are up to date.
+                * but first the most common case of merging one remote.
+                */
+               finish_up_to_date("Already up-to-date.");
+               return 0;
+       } else if (allow_fast_forward && !remoteheads->next &&
+                       !common->next &&
+                       !hashcmp(common->item->object.sha1, head)) {
+               /* Again the most common case of merging one remote. */
+               struct strbuf msg = STRBUF_INIT;
+               struct object *o;
+               char hex[41];
+               strcpy(hex, find_unique_abbrev(head, DEFAULT_ABBREV));
+               if (verbosity >= 0)
+                       printf("Updating %s..%s\n",
+                               hex,
+                               find_unique_abbrev(remoteheads->item->object.sha1,
+                               DEFAULT_ABBREV));
+               strbuf_addstr(&msg, "Fast-forward");
+               if (have_message)
+                       strbuf_addstr(&msg,
+                               " (no commit created; -m option ignored)");
+               o = peel_to_type(sha1_to_hex(remoteheads->item->object.sha1),
+                       0, NULL, OBJ_COMMIT);
+               if (!o)
+                       return 1;
+               if (checkout_fast_forward(head, remoteheads->item->object.sha1))
+                       return 1;
+               finish(o->sha1, msg.buf);
+               drop_save();
+               return 0;
+       } else if (!remoteheads->next && common->next)
+               ;
+               /*
+                * We are not doing octopus and not fast-forward.  Need
+                * a real merge.
+                */
+       else if (!remoteheads->next && !common->next && option_commit) {
+               /*
+                * We are not doing octopus, not fast-forward, and have
+                * only one common.
+                */
+               refresh_cache(REFRESH_QUIET);
+               if (allow_trivial && !fast_forward_only) {
+                       /* See if it is really trivial. */
+                       git_committer_info(IDENT_ERROR_ON_NO_NAME);
+                       printf("Trying really trivial in-index merge...\n");
+                       if (!read_tree_trivial(common->item->object.sha1,
+                                       head, remoteheads->item->object.sha1))
+                               return merge_trivial();
+                       printf("Nope.\n");
+               }
+       } else {
+               /*
+                * An octopus.  If we can reach all the remote we are up
+                * to date.
+                */
+               int up_to_date = 1;
+               struct commit_list *j;
+               for (j = remoteheads; j; j = j->next) {
+                       struct commit_list *common_one;
+                       /*
+                        * Here we *have* to calculate the individual
+                        * merge_bases again, otherwise "git merge HEAD^
+                        * HEAD^^" would be missed.
+                        */
+                       common_one = get_merge_bases(lookup_commit(head),
+                               j->item, 1);
+                       if (hashcmp(common_one->item->object.sha1,
+                               j->item->object.sha1)) {
+                               up_to_date = 0;
+                               break;
+                       }
+               }
+               if (up_to_date) {
+                       finish_up_to_date("Already up-to-date. Yeeah!");
+                       return 0;
+               }
+       }
+       if (fast_forward_only)
+               die("Not possible to fast-forward, aborting.");
+       /* We are going to make a new commit. */
+       git_committer_info(IDENT_ERROR_ON_NO_NAME);
+       /*
+        * At this point, we need a real merge.  No matter what strategy
+        * we use, it would operate on the index, possibly affecting the
+        * working tree, and when resolved cleanly, have the desired
+        * tree in the index -- this means that the index must be in
+        * sync with the head commit.  The strategies are responsible
+        * to ensure this.
+        */
+       if (use_strategies_nr != 1) {
+               /*
+                * Stash away the local changes so that we can try more
+                * than one.
+                */
+               save_state();
+       } else {
+               memcpy(stash, null_sha1, 20);
+       }
+       for (i = 0; i < use_strategies_nr; i++) {
+               int ret;
+               if (i) {
+                       printf("Rewinding the tree to pristine...\n");
+                       restore_state();
+               }
+               if (use_strategies_nr != 1)
+                       printf("Trying merge strategy %s...\n",
+                               use_strategies[i]->name);
+               /*
+                * Remember which strategy left the state in the working
+                * tree.
+                */
+               wt_strategy = use_strategies[i]->name;
+               ret = try_merge_strategy(use_strategies[i]->name,
+                       common, head_arg);
+               if (!option_commit && !ret) {
+                       merge_was_ok = 1;
+                       /*
+                        * This is necessary here just to avoid writing
+                        * the tree, but later we will *not* exit with
+                        * status code 1 because merge_was_ok is set.
+                        */
+                       ret = 1;
+               }
+               if (ret) {
+                       /*
+                        * The backend exits with 1 when conflicts are
+                        * left to be resolved, with 2 when it does not
+                        * handle the given merge at all.
+                        */
+                       if (ret == 1) {
+                               int cnt = evaluate_result();
+                               if (best_cnt <= 0 || cnt <= best_cnt) {
+                                       best_strategy = use_strategies[i]->name;
+                                       best_cnt = cnt;
+                               }
+                       }
+                       if (merge_was_ok)
+                               break;
+                       else
+                               continue;
+               }
+               /* Automerge succeeded. */
+               write_tree_trivial(result_tree);
+               automerge_was_ok = 1;
+               break;
+       }
+       /*
+        * If we have a resulting tree, that means the strategy module
+        * auto resolved the merge cleanly.
+        */
+       if (automerge_was_ok)
+               return finish_automerge(common, result_tree, wt_strategy);
+       /*
+        * Pick the result from the best strategy and have the user fix
+        * it up.
+        */
+       if (!best_strategy) {
+               restore_state();
+               if (use_strategies_nr > 1)
+                       fprintf(stderr,
+                               "No merge strategy handled the merge.\n");
+               else
+                       fprintf(stderr, "Merge with strategy %s failed.\n",
+                               use_strategies[0]->name);
+               return 2;
+       } else if (best_strategy == wt_strategy)
+               ; /* We already have its result in the working tree. */
+       else {
+               printf("Rewinding the tree to pristine...\n");
+               restore_state();
+               printf("Using the %s to prepare resolving by hand.\n",
+                       best_strategy);
+               try_merge_strategy(best_strategy, common, head_arg);
+       }
+       if (squash)
+               finish(NULL, NULL);
+       else {
+               int fd;
+               struct commit_list *j;
+               for (j = remoteheads; j; j = j->next)
+                       strbuf_addf(&buf, "%s\n",
+                               sha1_to_hex(j->item->object.sha1));
+               fd = open(git_path("MERGE_HEAD"), O_WRONLY | O_CREAT, 0666);
+               if (fd < 0)
+                       die_errno("Could not open '%s' for writing",
+                                 git_path("MERGE_HEAD"));
+               if (write_in_full(fd, buf.buf, buf.len) != buf.len)
+                       die_errno("Could not write to '%s'", git_path("MERGE_HEAD"));
+               close(fd);
+               strbuf_addch(&merge_msg, '\n');
+               fd = open(git_path("MERGE_MSG"), O_WRONLY | O_CREAT, 0666);
+               if (fd < 0)
+                       die_errno("Could not open '%s' for writing",
+                                 git_path("MERGE_MSG"));
+               if (write_in_full(fd, merge_msg.buf, merge_msg.len) !=
+                       merge_msg.len)
+                       die_errno("Could not write to '%s'", git_path("MERGE_MSG"));
+               close(fd);
+               fd = open(git_path("MERGE_MODE"), O_WRONLY | O_CREAT | O_TRUNC, 0666);
+               if (fd < 0)
+                       die_errno("Could not open '%s' for writing",
+                                 git_path("MERGE_MODE"));
+               strbuf_reset(&buf);
+               if (!allow_fast_forward)
+                       strbuf_addf(&buf, "no-ff");
+               if (write_in_full(fd, buf.buf, buf.len) != buf.len)
+                       die_errno("Could not write to '%s'", git_path("MERGE_MODE"));
+               close(fd);
+       }
+       if (merge_was_ok) {
+               fprintf(stderr, "Automatic merge went well; "
+                       "stopped before committing as requested\n");
+               return 0;
+       } else
+               return suggest_conflicts();
+ }