1 files changed, 535 insertions, 268 deletions

diff --git a/builtin/merge.c b/builtin/merge.c
index 9403747b6a..470fc57c5d 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -25,6 +25,9 @@
 #include "help.h"
 #include "merge-recursive.h"
 #include "resolve-undo.h"
+#include "remote.h"
+#include "fmt-merge-msg.h"
+#include "gpg-interface.h"
 
 #define DEFAULT_TWOHEAD (1<<0)
 #define DEFAULT_OCTOPUS (1<<1)
@@ -37,27 +40,31 @@ struct strategy {
 };
 
 static const char * const builtin_merge_usage[] = {
-	"git merge [options] <remote>...",
-	"git merge [options] <msg> HEAD <remote>",
+	"git merge [options] [<commit>...]",
+	"git merge [options] <msg> HEAD <commit>",
+	"git merge --abort",
 	NULL
 };
 
-static int show_diffstat = 1, shortlog_len, squash;
+static int show_diffstat = 1, shortlog_len = -1, squash;
 static int option_commit = 1, allow_fast_forward = 1;
-static int fast_forward_only;
+static int fast_forward_only, option_edit = -1;
 static int allow_trivial = 1, have_message;
-static struct strbuf merge_msg;
-static struct commit_list *remoteheads;
-static unsigned char head[20], stash[20];
+static int overwrite_ignore = 1;
+static struct strbuf merge_msg = STRBUF_INIT;
 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 char *branch_mergeoptions;
 static int option_renormalize;
 static int verbosity;
 static int allow_rerere_auto;
 static int abort_current_merge;
+static int show_progress = -1;
+static int default_to_upstream;
+static const char *sign_commit;
 
 static struct strategy all_strategy[] = {
 	{ "recursive",  DEFAULT_TWOHEAD | NO_TRIVIAL },
@@ -80,7 +87,7 @@ static int option_parse_message(const struct option *opt,
 		strbuf_addf(buf, "%s%s", buf->len ? "\n\n" : "", arg);
 		have_message = 1;
 	} else
-		return error("switch `m' requires a value");
+		return error(_("switch `m' requires a value"));
 	return 0;
 }
 
@@ -117,13 +124,13 @@ static struct strategy *get_strategy(const char *name)
 		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:");
+		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:");
+			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");
@@ -185,6 +192,8 @@ static struct option builtin_merge_options[] = {
 		"create a single commit instead of doing a merge"),
 	OPT_BOOLEAN(0, "commit", &option_commit,
 		"perform a commit if the merge succeeds (default)"),
+	OPT_BOOL('e', "edit", &option_edit,
+		"edit message before committing"),
 	OPT_BOOLEAN(0, "ff", &allow_fast_forward,
 		"allow fast-forward (default)"),
 	OPT_BOOLEAN(0, "ff-only", &fast_forward_only,
@@ -195,11 +204,15 @@ static struct option builtin_merge_options[] = {
 	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)",
+		"merge commit message (for a non-fast-forward merge)",
 		option_parse_message),
 	OPT__VERBOSITY(&verbosity),
 	OPT_BOOLEAN(0, "abort", &abort_current_merge,
 		"abort the current in-progress merge"),
+	OPT_SET_INT(0, "progress", &show_progress, "force progress reporting", 1),
+	{ OPTION_STRING, 'S', "gpg-sign", &sign_commit, "key id",
+	  "GPG sign commit", PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
+	OPT_BOOLEAN(0, "overwrite-ignore", &overwrite_ignore, "update ignored files (default)"),
 	OPT_END()
 };
 
@@ -211,7 +224,7 @@ static void drop_save(void)
 	unlink(git_path("MERGE_MODE"));
 }
 
-static void save_state(void)
+static int save_state(unsigned char *stash)
 {
 	int len;
 	struct child_process cp;
@@ -224,17 +237,18 @@ static void save_state(void)
 	cp.git_cmd = 1;
 
 	if (start_command(&cp))
-		die("could not run stash.");
+		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;
+		die(_("stash failed"));
+	else if (!len)		/* no changes */
+		return -1;
 	strbuf_setlen(&buffer, buffer.len-1);
 	if (get_sha1(buffer.buf, stash))
-		die("not a valid object: %s", buffer.buf);
+		die(_("not a valid object: %s"), buffer.buf);
+	return 0;
 }
 
 static void read_empty(unsigned const char *sha1, int verbose)
@@ -252,7 +266,7 @@ static void read_empty(unsigned const char *sha1, int verbose)
 	args[i] = NULL;
 
 	if (run_command_v_opt(args, RUN_GIT_CMD))
-		die("read-tree failed");
+		die(_("read-tree failed"));
 }
 
 static void reset_hard(unsigned const char *sha1, int verbose)
@@ -269,10 +283,11 @@ static void reset_hard(unsigned const char *sha1, int verbose)
 	args[i] = NULL;
 
 	if (run_command_v_opt(args, RUN_GIT_CMD))
-		die("read-tree failed");
+		die(_("read-tree failed"));
 }
 
-static void restore_state(void)
+static void restore_state(const unsigned char *head,
+			  const unsigned char *stash)
 {
 	struct strbuf sb = STRBUF_INIT;
 	const char *args[] = { "stash", "apply", NULL, NULL };
@@ -298,29 +313,29 @@ static void restore_state(void)
 static void finish_up_to_date(const char *msg)
 {
 	if (verbosity >= 0)
-		printf("%s%s\n", squash ? " (nothing to squash)" : "", msg);
+		printf("%s%s\n", squash ? _(" (nothing to squash)") : "", msg);
 	drop_save();
 }
 
-static void squash_message(void)
+static void squash_message(struct commit *commit, struct commit_list *remoteheads)
 {
 	struct rev_info rev;
-	struct commit *commit;
 	struct strbuf out = STRBUF_INIT;
 	struct commit_list *j;
+	const char *filename;
 	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);
+	printf(_("Squash commit -- not updating HEAD\n"));
+	filename = git_path("SQUASH_MSG");
+	fd = open(filename, O_WRONLY | O_CREAT, 0666);
 	if (fd < 0)
-		die_errno("Could not write to '%s'", git_path("SQUASH_MSG"));
+		die_errno(_("Could not write to '%s'"), filename);
 
 	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);
 
@@ -329,28 +344,32 @@ static void squash_message(void)
 
 	setup_revisions(0, NULL, &rev, NULL);
 	if (prepare_revision_walk(&rev))
-		die("revision walk setup failed");
+		die(_("revision walk setup failed"));
 
 	ctx.abbrev = rev.abbrev;
 	ctx.date_mode = rev.date_mode;
+	ctx.fmt = rev.commit_format;
 
 	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);
+		pretty_print_commit(&ctx, commit, &out);
 	}
 	if (write(fd, out.buf, out.len) < 0)
-		die_errno("Writing SQUASH_MSG");
+		die_errno(_("Writing SQUASH_MSG"));
 	if (close(fd))
-		die_errno("Finishing SQUASH_MSG");
+		die_errno(_("Finishing SQUASH_MSG"));
 	strbuf_release(&out);
 }
 
-static void finish(const unsigned char *new_head, const char *msg)
+static void finish(struct commit *head_commit,
+		   struct commit_list *remoteheads,
+		   const unsigned char *new_head, const char *msg)
 {
 	struct strbuf reflog_message = STRBUF_INIT;
+	const unsigned char *head = head_commit->object.sha1;
 
 	if (!msg)
 		strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
@@ -361,10 +380,10 @@ static void finish(const unsigned char *new_head, const char *msg)
 			getenv("GIT_REFLOG_ACTION"), msg);
 	}
 	if (squash) {
-		squash_message();
+		squash_message(head_commit, remoteheads);
 	} else {
 		if (verbosity >= 0 && !merge_msg.len)
-			printf("No merge message -- not updating HEAD\n");
+			printf(_("No merge message -- not updating HEAD\n"));
 		else {
 			const char *argv_gc_auto[] = { "gc", "--auto", NULL };
 			update_ref(reflog_message.buf, "HEAD",
@@ -380,13 +399,13 @@ static void finish(const unsigned char *new_head, const char *msg)
 	if (new_head && show_diffstat) {
 		struct diff_options opts;
 		diff_setup(&opts);
+		opts.stat_width = -1; /* use full terminal width */
+		opts.stat_graph_width = -1; /* respect statGraphWidth config */
 		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");
+			die(_("diff_setup_done failed"));
 		diff_tree_sha1(head, new_head, "", &opts);
 		diffcore_std(&opts);
 		diff_flush(&opts);
@@ -401,8 +420,8 @@ static void finish(const unsigned char *new_head, const char *msg)
 /* 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 commit *remote_head;
+	unsigned char branch_head[20];
 	struct strbuf buf = STRBUF_INIT;
 	struct strbuf bname = STRBUF_INIT;
 	const char *ptr;
@@ -413,9 +432,9 @@ static void merge_name(const char *remote, struct strbuf *msg)
 	remote = bname.buf;
 
 	memset(branch_head, 0, sizeof(branch_head));
-	remote_head = peel_to_type(remote, 0, NULL, OBJ_COMMIT);
+	remote_head = get_merge_parent(remote);
 	if (!remote_head)
-		die("'%s' does not point to a commit", remote);
+		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/")) {
@@ -423,6 +442,11 @@ static void merge_name(const char *remote, struct strbuf *msg)
 				    sha1_to_hex(branch_head), remote);
 			goto cleanup;
 		}
+		if (!prefixcmp(found_ref, "refs/tags/")) {
+			strbuf_addf(msg, "%s\t\ttag '%s' of .\n",
+				    sha1_to_hex(branch_head), remote);
+			goto cleanup;
+		}
 		if (!prefixcmp(found_ref, "refs/remotes/")) {
 			strbuf_addf(msg, "%s\t\tremote-tracking branch '%s' of .\n",
 				    sha1_to_hex(branch_head), remote);
@@ -461,10 +485,10 @@ static void merge_name(const char *remote, struct strbuf *msg)
 		strbuf_addstr(&truname, "refs/heads/");
 		strbuf_addstr(&truname, remote);
 		strbuf_setlen(&truname, truname.len - len);
-		if (resolve_ref(truname.buf, buf_sha, 1, NULL)) {
+		if (ref_exists(truname.buf)) {
 			strbuf_addf(msg,
 				    "%s\t\tbranch '%s'%s of .\n",
-				    sha1_to_hex(remote_head->sha1),
+				    sha1_to_hex(remote_head->object.sha1),
 				    truname.buf + 11,
 				    (early ? " (early part)" : ""));
 			strbuf_release(&truname);
@@ -474,14 +498,16 @@ static void merge_name(const char *remote, struct strbuf *msg)
 
 	if (!strcmp(remote, "FETCH_HEAD") &&
 			!access(git_path("FETCH_HEAD"), R_OK)) {
+		const char *filename;
 		FILE *fp;
 		struct strbuf line = STRBUF_INIT;
 		char *ptr;
 
-		fp = fopen(git_path("FETCH_HEAD"), "r");
+		filename = git_path("FETCH_HEAD");
+		fp = fopen(filename, "r");
 		if (!fp)
-			die_errno("could not open '%s' for reading",
-				  git_path("FETCH_HEAD"));
+			die_errno(_("could not open '%s' for reading"),
+				  filename);
 		strbuf_getline(&line, fp, '\n');
 		fclose(fp);
 		ptr = strstr(line.buf, "\tnot-for-merge\t");
@@ -492,32 +518,42 @@ static void merge_name(const char *remote, struct strbuf *msg)
 		goto cleanup;
 	}
 	strbuf_addf(msg, "%s\t\tcommit '%s'\n",
-		sha1_to_hex(remote_head->sha1), remote);
+		sha1_to_hex(remote_head->object.sha1), remote);
 cleanup:
 	strbuf_release(&buf);
 	strbuf_release(&bname);
 }
 
+static void parse_branch_merge_options(char *bmo)
+{
+	const char **argv;
+	int argc;
+
+	if (!bmo)
+		return;
+	argc = split_cmdline(bmo, &argv);
+	if (argc < 0)
+		die(_("Bad branch.%s.mergeoptions string: %s"), branch,
+		    split_cmdline_strerror(argc));
+	argv = xrealloc(argv, sizeof(*argv) * (argc + 2));
+	memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
+	argc++;
+	argv[0] = "branch.*.mergeoptions";
+	parse_options(argc, argv, NULL, builtin_merge_options,
+		      builtin_merge_usage, 0);
+	free(argv);
+}
+
 static int git_merge_config(const char *k, const char *v, void *cb)
 {
+	int status;
+
 	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: %s", branch,
-			    split_cmdline_strerror(argc));
-		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);
+		free(branch_mergeoptions);
+		branch_mergeoptions = xstrdup(v);
+		return 0;
 	}
 
 	if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
@@ -528,15 +564,26 @@ static int git_merge_config(const char *k, const char *v, void *cb)
 		return git_config_string(&pull_octopus, k, v);
 	else if (!strcmp(k, "merge.renormalize"))
 		option_renormalize = git_config_bool(k, v);
-	else if (!strcmp(k, "merge.log") || !strcmp(k, "merge.summary")) {
-		int is_bool;
-		shortlog_len = git_config_bool_or_int(k, v, &is_bool);
-		if (!is_bool && shortlog_len < 0)
-			return error("%s: negative length %s", k, v);
-		if (is_bool && shortlog_len)
-			shortlog_len = DEFAULT_MERGE_LOG_LEN;
+	else if (!strcmp(k, "merge.ff")) {
+		int boolval = git_config_maybe_bool(k, v);
+		if (0 <= boolval) {
+			allow_fast_forward = boolval;
+		} else if (v && !strcmp(v, "only")) {
+			allow_fast_forward = 1;
+			fast_forward_only = 1;
+		} /* do not barf on values from future versions of git */
+		return 0;
+	} else if (!strcmp(k, "merge.defaulttoupstream")) {
+		default_to_upstream = git_config_bool(k, v);
 		return 0;
 	}
+
+	status = fmt_merge_msg_config(k, v, cb);
+	if (status)
+		return status;
+	status = git_gpg_config(k, v, NULL);
+	if (status)
+		return status;
 	return git_diff_ui_config(k, v, cb);
 }
 
@@ -579,7 +626,15 @@ static int read_tree_trivial(unsigned char *common, unsigned char *head,
 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");
+		die(_("git write-tree failed to write a tree"));
+}
+
+static const char *merge_argument(struct commit *commit)
+{
+	if (commit)
+		return sha1_to_hex(commit->object.sha1);
+	else
+		return EMPTY_TREE_SHA1_HEX;
 }
 
 int try_merge_command(const char *strategy, size_t xopts_nr,
@@ -602,11 +657,11 @@ int try_merge_command(const char *strategy, size_t xopts_nr,
 		args[i++] = s;
 	}
 	for (j = common; j; j = j->next)
-		args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
+		args[i++] = xstrdup(merge_argument(j->item));
 	args[i++] = "--";
 	args[i++] = head_arg;
 	for (j = remotes; j; j = j->next)
-		args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
+		args[i++] = xstrdup(merge_argument(j->item));
 	args[i] = NULL;
 	ret = run_command_v_opt(args, RUN_GIT_CMD);
 	strbuf_release(&buf);
@@ -621,14 +676,15 @@ int try_merge_command(const char *strategy, size_t xopts_nr,
 	free(args);
 	discard_cache();
 	if (read_cache() < 0)
-		die("failed to read the cache");
+		die(_("failed to read the cache"));
 	resolve_undo_clear();
 
 	return ret;
 }
 
 static int try_merge_strategy(const char *strategy, struct commit_list *common,
-			      const char *head_arg)
+			      struct commit_list *remoteheads,
+			      struct commit *head, const char *head_arg)
 {
 	int index_fd;
 	struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
@@ -638,7 +694,7 @@ static int try_merge_strategy(const char *strategy, struct commit_list *common,
 	if (active_cache_changed &&
 			(write_cache(index_fd, active_cache, active_nr) ||
 			 commit_locked_index(lock)))
-		return error("Unable to write index.");
+		return error(_("Unable to write index."));
 	rollback_lock_file(lock);
 
 	if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
@@ -651,7 +707,7 @@ static int try_merge_strategy(const char *strategy, struct commit_list *common,
 		struct commit_list *j;
 
 		if (remoteheads->next) {
-			error("Not handling anything other than two heads merge.");
+			error(_("Not handling anything other than two heads merge."));
 			return 2;
 		}
 
@@ -660,24 +716,26 @@ static int try_merge_strategy(const char *strategy, struct commit_list *common,
 			o.subtree_shift = "";
 
 		o.renormalize = option_renormalize;
+		o.show_rename_progress =
+			show_progress == -1 ? isatty(2) : show_progress;
 
 		for (x = 0; x < xopts_nr; x++)
 			if (parse_merge_opt(&o, xopts[x]))
-				die("Unknown option for merge-recursive: -X%s", xopts[x]);
+				die(_("Unknown option for merge-recursive: -X%s"), xopts[x]);
 
 		o.branch1 = head_arg;
-		o.branch2 = remoteheads->item->util;
+		o.branch2 = merge_remote_util(remoteheads->item)->name;
 
 		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),
+		clean = merge_recursive(&o, 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());
+			die (_("unable to write %s"), get_index_file());
 		rollback_lock_file(lock);
 		return clean ? 0 : 1;
 	} else {
@@ -721,10 +779,12 @@ int checkout_fast_forward(const unsigned char *head, const unsigned char *remote
 	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;
+	if (overwrite_ignore) {
+		memset(&dir, 0, sizeof(dir));
+		dir.flags |= DIR_SHOW_IGNORED;
+		setup_standard_excludes(&dir);
+		opts.dir = &dir;
+	}
 
 	opts.head_idx = 1;
 	opts.src_index = &the_index;
@@ -749,7 +809,7 @@ int checkout_fast_forward(const unsigned char *head, const unsigned char *remote
 		return -1;
 	if (write_cache(fd, active_cache, active_nr) ||
 		commit_locked_index(lock_file))
-		die("unable to write new index file");
+		die(_("unable to write new index file"));
 	return 0;
 }
 
@@ -797,49 +857,110 @@ static void add_strategies(const char *string, unsigned attr)
 
 }
 
-static int merge_trivial(void)
+static void write_merge_msg(struct strbuf *msg)
+{
+	const char *filename = git_path("MERGE_MSG");
+	int fd = open(filename, O_WRONLY | O_CREAT, 0666);
+	if (fd < 0)
+		die_errno(_("Could not open '%s' for writing"),
+			  filename);
+	if (write_in_full(fd, msg->buf, msg->len) != msg->len)
+		die_errno(_("Could not write to '%s'"), filename);
+	close(fd);
+}
+
+static void read_merge_msg(struct strbuf *msg)
+{
+	const char *filename = git_path("MERGE_MSG");
+	strbuf_reset(msg);
+	if (strbuf_read_file(msg, filename, 0) < 0)
+		die_errno(_("Could not read from '%s'"), filename);
+}
+
+static void write_merge_state(struct commit_list *);
+static void abort_commit(struct commit_list *remoteheads, const char *err_msg)
+{
+	if (err_msg)
+		error("%s", err_msg);
+	fprintf(stderr,
+		_("Not committing merge; use 'git commit' to complete the merge.\n"));
+	write_merge_state(remoteheads);
+	exit(1);
+}
+
+static const char merge_editor_comment[] =
+N_("Please enter a commit message to explain why this merge is necessary,\n"
+   "especially if it merges an updated upstream into a topic branch.\n"
+   "\n"
+   "Lines starting with '#' will be ignored, and an empty message aborts\n"
+   "the commit.\n");
+
+static void prepare_to_commit(struct commit_list *remoteheads)
+{
+	struct strbuf msg = STRBUF_INIT;
+	const char *comment = _(merge_editor_comment);
+	strbuf_addbuf(&msg, &merge_msg);
+	strbuf_addch(&msg, '\n');
+	if (0 < option_edit)
+		strbuf_add_lines(&msg, "# ", comment, strlen(comment));
+	write_merge_msg(&msg);
+	run_hook(get_index_file(), "prepare-commit-msg",
+		 git_path("MERGE_MSG"), "merge", NULL, NULL);
+	if (0 < option_edit) {
+		if (launch_editor(git_path("MERGE_MSG"), NULL, NULL))
+			abort_commit(remoteheads, NULL);
+	}
+	read_merge_msg(&msg);
+	stripspace(&msg, 0 < option_edit);
+	if (!msg.len)
+		abort_commit(remoteheads, _("Empty commit message."));
+	strbuf_release(&merge_msg);
+	strbuf_addbuf(&merge_msg, &msg);
+	strbuf_release(&msg);
+}
+
+static int merge_trivial(struct commit *head, struct commit_list *remoteheads)
 {
 	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);
+	printf(_("Wonderful.\n"));
+	parent->item = 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");
+	prepare_to_commit(remoteheads);
+	if (commit_tree(&merge_msg, result_tree, parent, result_commit, NULL,
+			sign_commit))
+		die(_("failed to write commit object"));
+	finish(head, remoteheads, result_commit, "In-index merge");
 	drop_save();
 	return 0;
 }
 
-static int finish_automerge(struct commit_list *common,
+static int finish_automerge(struct commit *head,
+			    int head_subsumed,
+			    struct commit_list *common,
+			    struct commit_list *remoteheads,
 			    unsigned char *result_tree,
 			    const char *wt_strategy)
 {
-	struct commit_list *parents = NULL, *j;
+	struct commit_list *parents = NULL;
 	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);
+	parents = remoteheads;
+	if (!head_subsumed || !allow_fast_forward)
+		commit_list_insert(head, &parents);
 	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);
+	prepare_to_commit(remoteheads);
+	if (commit_tree(&merge_msg, result_tree, parents, result_commit,
+			NULL, sign_commit))
+		die(_("failed to write commit object"));
+	strbuf_addf(&buf, "Merge made by the '%s' strategy.", wt_strategy);
+	finish(head, remoteheads, result_commit, buf.buf);
 	strbuf_release(&buf);
 	drop_save();
 	return 0;
@@ -847,13 +968,14 @@ static int finish_automerge(struct commit_list *common,
 
 static int suggest_conflicts(int renormalizing)
 {
+	const char *filename;
 	FILE *fp;
 	int pos;
 
-	fp = fopen(git_path("MERGE_MSG"), "a");
+	filename = git_path("MERGE_MSG");
+	fp = fopen(filename, "a");
 	if (!fp)
-		die_errno("Could not open '%s' for writing",
-			  git_path("MERGE_MSG"));
+		die_errno(_("Could not open '%s' for writing"), filename);
 	fprintf(fp, "\nConflicts:\n");
 	for (pos = 0; pos < active_nr; pos++) {
 		struct cache_entry *ce = active_cache[pos];
@@ -868,12 +990,13 @@ static int suggest_conflicts(int renormalizing)
 	}
 	fclose(fp);
 	rerere(allow_rerere_auto);
-	printf("Automatic merge failed; "
-			"fix conflicts and then commit the result.\n");
+	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)
+static struct commit *is_old_style_invocation(int argc, const char **argv,
+					      const unsigned char *head)
 {
 	struct commit *second_token = NULL;
 	if (argc > 2) {
@@ -883,7 +1006,7 @@ static struct commit *is_old_style_invocation(int argc, const char **argv)
 			return NULL;
 		second_token = lookup_commit_reference_gently(second_sha1, 0);
 		if (!second_token)
-			die("'%s' is not a commit", argv[1]);
+			die(_("'%s' is not a commit"), argv[1]);
 		if (hashcmp(second_token->object.sha1, head))
 			return NULL;
 	}
@@ -913,16 +1036,148 @@ static int evaluate_result(void)
 	return cnt;
 }
 
+/*
+ * Pretend as if the user told us to merge with the tracking
+ * branch we have for the upstream of the current branch
+ */
+static int setup_with_upstream(const char ***argv)
+{
+	struct branch *branch = branch_get(NULL);
+	int i;
+	const char **args;
+
+	if (!branch)
+		die(_("No current branch."));
+	if (!branch->remote)
+		die(_("No remote for the current branch."));
+	if (!branch->merge_nr)
+		die(_("No default upstream defined for the current branch."));
+
+	args = xcalloc(branch->merge_nr + 1, sizeof(char *));
+	for (i = 0; i < branch->merge_nr; i++) {
+		if (!branch->merge[i]->dst)
+			die(_("No remote tracking branch for %s from %s"),
+			    branch->merge[i]->src, branch->remote_name);
+		args[i] = branch->merge[i]->dst;
+	}
+	args[i] = NULL;
+	*argv = args;
+	return i;
+}
+
+static void write_merge_state(struct commit_list *remoteheads)
+{
+	const char *filename;
+	int fd;
+	struct commit_list *j;
+	struct strbuf buf = STRBUF_INIT;
+
+	for (j = remoteheads; j; j = j->next) {
+		unsigned const char *sha1;
+		struct commit *c = j->item;
+		if (c->util && merge_remote_util(c)->obj) {
+			sha1 = merge_remote_util(c)->obj->sha1;
+		} else {
+			sha1 = c->object.sha1;
+		}
+		strbuf_addf(&buf, "%s\n", sha1_to_hex(sha1));
+	}
+	filename = git_path("MERGE_HEAD");
+	fd = open(filename, O_WRONLY | O_CREAT, 0666);
+	if (fd < 0)
+		die_errno(_("Could not open '%s' for writing"), filename);
+	if (write_in_full(fd, buf.buf, buf.len) != buf.len)
+		die_errno(_("Could not write to '%s'"), filename);
+	close(fd);
+	strbuf_addch(&merge_msg, '\n');
+	write_merge_msg(&merge_msg);
+
+	filename = git_path("MERGE_MODE");
+	fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
+	if (fd < 0)
+		die_errno(_("Could not open '%s' for writing"), filename);
+	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'"), filename);
+	close(fd);
+}
+
+static int default_edit_option(void)
+{
+	static const char name[] = "GIT_MERGE_AUTOEDIT";
+	const char *e = getenv(name);
+	struct stat st_stdin, st_stdout;
+
+	if (have_message)
+		/* an explicit -m msg without --[no-]edit */
+		return 0;
+
+	if (e) {
+		int v = git_config_maybe_bool(name, e);
+		if (v < 0)
+			die("Bad value '%s' in environment '%s'", e, name);
+		return v;
+	}
+
+	/* Use editor if stdin and stdout are the same and is a tty */
+	return (!fstat(0, &st_stdin) &&
+		!fstat(1, &st_stdout) &&
+		isatty(0) && isatty(1) &&
+		st_stdin.st_dev == st_stdout.st_dev &&
+		st_stdin.st_ino == st_stdout.st_ino &&
+		st_stdin.st_mode == st_stdout.st_mode);
+}
+
+static struct commit_list *collect_parents(struct commit *head_commit,
+					   int *head_subsumed,
+					   int argc, const char **argv)
+{
+	int i;
+	struct commit_list *remoteheads = NULL, *parents, *next;
+	struct commit_list **remotes = &remoteheads;
+
+	if (head_commit)
+		remotes = &commit_list_insert(head_commit, remotes)->next;
+	for (i = 0; i < argc; i++) {
+		struct commit *commit = get_merge_parent(argv[i]);
+		if (!commit)
+			die(_("%s - not something we can merge"), argv[i]);
+		remotes = &commit_list_insert(commit, remotes)->next;
+	}
+	*remotes = NULL;
+
+	parents = reduce_heads(remoteheads);
+
+	*head_subsumed = 1; /* we will flip this to 0 when we find it */
+	for (remoteheads = NULL, remotes = &remoteheads;
+	     parents;
+	     parents = next) {
+		struct commit *commit = parents->item;
+		next = parents->next;
+		if (commit == head_commit)
+			*head_subsumed = 0;
+		else
+			remotes = &commit_list_insert(commit, remotes)->next;
+	}
+	return remoteheads;
+}
+
 int cmd_merge(int argc, const char **argv, const char *prefix)
 {
 	unsigned char result_tree[20];
+	unsigned char stash[20];
+	unsigned char head_sha1[20];
+	struct commit *head_commit;
 	struct strbuf buf = STRBUF_INIT;
 	const char *head_arg;
-	int flag, head_invalid = 0, i;
+	int flag, i, ret = 0, head_subsumed;
 	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;
+	struct commit_list *remoteheads, *p;
+	void *branch_to_free;
 
 	if (argc == 2 && !strcmp(argv[1], "-h"))
 		usage_with_options(builtin_merge_usage, builtin_merge_options);
@@ -931,30 +1186,36 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 	 * Check if we are _not_ on a detached HEAD, i.e. if there is a
 	 * current branch.
 	 */
-	branch = resolve_ref("HEAD", head, 0, &flag);
+	branch = branch_to_free = resolve_refdup("HEAD", head_sha1, 0, &flag);
 	if (branch && !prefixcmp(branch, "refs/heads/"))
 		branch += 11;
-	if (is_null_sha1(head))
-		head_invalid = 1;
+	if (!branch || is_null_sha1(head_sha1))
+		head_commit = NULL;
+	else
+		head_commit = lookup_commit_or_die(head_sha1, "HEAD");
 
 	git_config(git_merge_config, NULL);
 
-	/* for color.ui */
-	if (diff_use_color_default == -1)
-		diff_use_color_default = git_use_color_default;
-
+	if (branch_mergeoptions)
+		parse_branch_merge_options(branch_mergeoptions);
 	argc = parse_options(argc, argv, prefix, builtin_merge_options,
 			builtin_merge_usage, 0);
+	if (shortlog_len < 0)
+		shortlog_len = (merge_log_config > 0) ? merge_log_config : 0;
+
+	if (verbosity < 0 && show_progress == -1)
+		show_progress = 0;
 
 	if (abort_current_merge) {
 		int nargc = 2;
 		const char *nargv[] = {"reset", "--merge", NULL};
 
 		if (!file_exists(git_path("MERGE_HEAD")))
-			die("There is no merge to abort (MERGE_HEAD missing).");
+			die(_("There is no merge to abort (MERGE_HEAD missing)."));
 
 		/* Invoke 'git reset --merge' */
-		return cmd_reset(nargc, nargv, prefix);
+		ret = cmd_reset(nargc, nargv, prefix);
+		goto done;
 	}
 
 	if (read_cache_unmerged())
@@ -966,10 +1227,17 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 		 * 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.");
+			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).");
+			die(_("You have not concluded your merge (MERGE_HEAD exists)."));
+	}
+	if (file_exists(git_path("CHERRY_PICK_HEAD"))) {
+		if (advice_resolve_conflict)
+			die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists).\n"
+			    "Please, commit your changes before you can merge."));
+		else
+			die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists)."));
 	}
 	resolve_undo_clear();
 
@@ -978,13 +1246,22 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 
 	if (squash) {
 		if (!allow_fast_forward)
-			die("You cannot combine --squash with --no-ff.");
+			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.");
+		die(_("You cannot combine --no-ff with --ff-only."));
 
+	if (!abort_current_merge) {
+		if (!argc) {
+			if (default_to_upstream)
+				argc = setup_with_upstream(&argv);
+			else
+				die(_("No commit specified and merge.defaultToUpstream not set."));
+		} else if (argc == 1 && !strcmp(argv[0], "-"))
+			argv[0] = "@{-1}";
+	}
 	if (!argc)
 		usage_with_options(builtin_merge_usage,
 			builtin_merge_options);
@@ -998,33 +1275,36 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 	 * additional safety measure to check for it.
 	 */
 
-	if (!have_message && is_old_style_invocation(argc, argv)) {
+	if (!have_message && head_commit &&
+	    is_old_style_invocation(argc, argv, head_commit->object.sha1)) {
 		strbuf_addstr(&merge_msg, argv[0]);
 		head_arg = argv[1];
 		argv += 2;
 		argc -= 2;
-	} else if (head_invalid) {
-		struct object *remote_head;
+		remoteheads = collect_parents(head_commit, &head_subsumed, argc, argv);
+	} else if (!head_commit) {
+		struct commit *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");
+			die(_("Can merge only exactly one commit into "
+				"empty head"));
 		if (squash)
-			die("Squash commit into empty head not supported yet");
+			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);
+			die(_("Non-fast-forward commit does not make sense into "
+			    "an empty head"));
+		remoteheads = collect_parents(head_commit, &head_subsumed, argc, argv);
+		remote_head = remoteheads->item;
 		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);
-		read_empty(remote_head->sha1, 0);
-		return 0;
+			die(_("%s - not something we can merge"), argv[0]);
+		read_empty(remote_head->object.sha1, 0);
+		update_ref("initial pull", "HEAD", remote_head->object.sha1,
+			   NULL, 0, DIE_ON_ERR);
+		goto done;
 	} else {
 		struct strbuf merge_names = STRBUF_INIT;
 
@@ -1032,52 +1312,56 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 		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.
+		 * All the rest are the commits being merged; prepare
+		 * the standard merge summary message to be appended
+		 * to the given message.
 		 */
-		for (i = 0; i < argc; i++)
-			merge_name(argv[i], &merge_names);
+		remoteheads = collect_parents(head_commit, &head_subsumed, argc, argv);
+		for (p = remoteheads; p; p = p->next)
+			merge_name(merge_remote_util(p->item)->name, &merge_names);
 
 		if (!have_message || shortlog_len) {
-			fmt_merge_msg(&merge_names, &merge_msg, !have_message,
-				      shortlog_len);
+			struct fmt_merge_msg_opts opts;
+			memset(&opts, 0, sizeof(opts));
+			opts.add_title = !have_message;
+			opts.shortlog_len = shortlog_len;
+
+			fmt_merge_msg(&merge_names, &merge_msg, &opts);
 			if (merge_msg.len)
 				strbuf_setlen(&merge_msg, merge_msg.len - 1);
 		}
 	}
 
-	if (head_invalid || !argc)
+	if (!head_commit || !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]);
+	for (p = remoteheads; p; p = p->next)
+		strbuf_addf(&buf, " %s", merge_remote_util(p->item)->name);
 	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);
+	for (p = remoteheads; p; p = p->next) {
+		struct commit *commit = p->item;
+		strbuf_addf(&buf, "GITHEAD_%s",
+			    sha1_to_hex(commit->object.sha1));
+		setenv(buf.buf, merge_remote_util(commit)->name, 1);
 		strbuf_reset(&buf);
+		if (!fast_forward_only &&
+		    merge_remote_util(commit) &&
+		    merge_remote_util(commit)->obj &&
+		    merge_remote_util(commit)->obj->type == OBJ_TAG)
+			allow_fast_forward = 0;
 	}
 
+	if (option_edit < 0)
+		option_edit = default_edit_option();
+
 	if (!use_strategies) {
-		if (!remoteheads->next)
+		if (!remoteheads)
+			; /* already up-to-date */
+		else if (!remoteheads->next)
 			add_strategies(pull_twohead, DEFAULT_TWOHEAD);
 		else
 			add_strategies(pull_octopus, DEFAULT_OCTOPUS);
@@ -1090,41 +1374,43 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 			allow_trivial = 0;
 	}
 
-	if (!remoteheads->next)
-		common = get_merge_bases(lookup_commit(head),
-				remoteheads->item, 1);
+	if (!remoteheads)
+		; /* already up-to-date */
+	else if (!remoteheads->next)
+		common = get_merge_bases(head_commit, remoteheads->item, 1);
 	else {
 		struct commit_list *list = remoteheads;
-		commit_list_insert(lookup_commit(head), &list);
+		commit_list_insert(head_commit, &list);
 		common = get_octopus_merge_bases(list);
 		free(list);
 	}
 
-	update_ref("updating ORIG_HEAD", "ORIG_HEAD", head, NULL, 0,
-		DIE_ON_ERR);
+	update_ref("updating ORIG_HEAD", "ORIG_HEAD", head_commit->object.sha1,
+		   NULL, 0, DIE_ON_ERR);
 
-	if (!common)
+	if (remoteheads && !common)
 		; /* No common ancestors found. We need a real merge. */
-	else if (!remoteheads->next && !common->next &&
-			common->item == remoteheads->item) {
+	else if (!remoteheads ||
+		 (!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;
+		goto done;
 	} else if (allow_fast_forward && !remoteheads->next &&
 			!common->next &&
-			!hashcmp(common->item->object.sha1, head)) {
+			!hashcmp(common->item->object.sha1, head_commit->object.sha1)) {
 		/* Again the most common case of merging one remote. */
 		struct strbuf msg = STRBUF_INIT;
-		struct object *o;
+		struct commit *commit;
 		char hex[41];
 
-		strcpy(hex, find_unique_abbrev(head, DEFAULT_ABBREV));
+		strcpy(hex, find_unique_abbrev(head_commit->object.sha1, DEFAULT_ABBREV));
 
 		if (verbosity >= 0)
-			printf("Updating %s..%s\n",
+			printf(_("Updating %s..%s\n"),
 				hex,
 				find_unique_abbrev(remoteheads->item->object.sha1,
 				DEFAULT_ABBREV));
@@ -1132,17 +1418,21 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 		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;
+		commit = remoteheads->item;
+		if (!commit) {
+			ret = 1;
+			goto done;
+		}
 
-		if (checkout_fast_forward(head, remoteheads->item->object.sha1))
-			return 1;
+		if (checkout_fast_forward(head_commit->object.sha1,
+					  commit->object.sha1)) {
+			ret = 1;
+			goto done;
+		}
 
-		finish(o->sha1, msg.buf);
+		finish(head_commit, remoteheads, commit->object.sha1, msg.buf);
 		drop_save();
-		return 0;
+		goto done;
 	} else if (!remoteheads->next && common->next)
 		;
 		/*
@@ -1158,11 +1448,14 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 		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");
+			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");
+					       head_commit->object.sha1,
+					       remoteheads->item->object.sha1)) {
+				ret = merge_trivial(head_commit, remoteheads);
+				goto done;
+			}
+			printf(_("Nope.\n"));
 		}
 	} else {
 		/*
@@ -1180,8 +1473,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 			 * merge_bases again, otherwise "git merge HEAD^
 			 * HEAD^^" would be missed.
 			 */
-			common_one = get_merge_bases(lookup_commit(head),
-				j->item, 1);
+			common_one = get_merge_bases(head_commit, j->item, 1);
 			if (hashcmp(common_one->item->object.sha1,
 				j->item->object.sha1)) {
 				up_to_date = 0;
@@ -1190,12 +1482,12 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 		}
 		if (up_to_date) {
 			finish_up_to_date("Already up-to-date. Yeeah!");
-			return 0;
+			goto done;
 		}
 	}
 
 	if (fast_forward_only)
-		die("Not possible to fast-forward, aborting.");
+		die(_("Not possible to fast-forward, aborting."));
 
 	/* We are going to make a new commit. */
 	git_committer_info(IDENT_ERROR_ON_NO_NAME);
@@ -1208,24 +1500,21 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 	 * 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);
-	}
+	if (use_strategies_nr == 1 ||
+	    /*
+	     * Stash away the local changes so that we can try more than one.
+	     */
+	    save_state(stash))
+		hashcpy(stash, null_sha1);
 
 	for (i = 0; i < use_strategies_nr; i++) {
 		int ret;
 		if (i) {
-			printf("Rewinding the tree to pristine...\n");
-			restore_state();
+			printf(_("Rewinding the tree to pristine...\n"));
+			restore_state(head_commit->object.sha1, stash);
 		}
 		if (use_strategies_nr != 1)
-			printf("Trying merge strategy %s...\n",
+			printf(_("Trying merge strategy %s...\n"),
 				use_strategies[i]->name);
 		/*
 		 * Remember which strategy left the state in the working
@@ -1234,7 +1523,8 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 		wt_strategy = use_strategies[i]->name;
 
 		ret = try_merge_strategy(use_strategies[i]->name,
-			common, head_arg);
+					 common, remoteheads,
+					 head_commit, head_arg);
 		if (!option_commit && !ret) {
 			merge_was_ok = 1;
 			/*
@@ -1275,73 +1565,50 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 	 * 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);
+	if (automerge_was_ok) {
+		ret = finish_automerge(head_commit, head_subsumed,
+				       common, remoteheads,
+				       result_tree, wt_strategy);
+		goto done;
+	}
 
 	/*
 	 * Pick the result from the best strategy and have the user fix
 	 * it up.
 	 */
 	if (!best_strategy) {
-		restore_state();
+		restore_state(head_commit->object.sha1, stash);
 		if (use_strategies_nr > 1)
 			fprintf(stderr,
-				"No merge strategy handled the merge.\n");
+				_("No merge strategy handled the merge.\n"));
 		else
-			fprintf(stderr, "Merge with strategy %s failed.\n",
+			fprintf(stderr, _("Merge with strategy %s failed.\n"),
 				use_strategies[0]->name);
-		return 2;
+		ret = 2;
+		goto done;
 	} 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",
+		printf(_("Rewinding the tree to pristine...\n"));
+		restore_state(head_commit->object.sha1, stash);
+		printf(_("Using the %s to prepare resolving by hand.\n"),
 			best_strategy);
-		try_merge_strategy(best_strategy, common, head_arg);
+		try_merge_strategy(best_strategy, common, remoteheads,
+				   head_commit, 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(option_renormalize);
+		finish(head_commit, remoteheads, NULL, NULL);
+	else
+		write_merge_state(remoteheads);
+
+	if (merge_was_ok)
+		fprintf(stderr, _("Automatic merge went well; "
+			"stopped before committing as requested\n"));
+	else
+		ret = suggest_conflicts(option_renormalize);
+
+done:
+	free(branch_to_free);
+	return ret;
 }