1 files changed, 33 insertions, 13 deletions

diff --git a/builtin/merge.c b/builtin/merge.c
index 0f03dff116..5a2a1eb797 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -550,6 +550,15 @@ static int git_merge_config(const char *k, const char *v, void *cb)
 		if (is_bool && shortlog_len)
 			shortlog_len = DEFAULT_MERGE_LOG_LEN;
 		return 0;
+	} 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;
@@ -599,6 +608,14 @@ static void write_tree_trivial(unsigned char *sha1)
 		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,
 		      const char **xopts, struct commit_list *common,
 		      const char *head_arg, struct commit_list *remotes)
@@ -619,11 +636,11 @@ 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);
@@ -831,7 +848,7 @@ static void read_merge_msg(void)
 {
 	strbuf_reset(&merge_msg);
 	if (strbuf_read_file(&merge_msg, git_path("MERGE_MSG"), 0) < 0)
-		die_errno("Could not read from '%s'", git_path("MERGE_MSG"));
+		die_errno(_("Could not read from '%s'"), git_path("MERGE_MSG"));
 }
 
 static void run_prepare_commit_msg(void)
@@ -971,16 +988,16 @@ static int setup_with_upstream(const char ***argv)
 	const char **args;
 
 	if (!branch)
-		die("No current branch.");
+		die(_("No current branch."));
 	if (!branch->remote)
-		die("No remote for the current branch.");
+		die(_("No remote for the current branch."));
 	if (!branch->merge_nr)
-		die("No default upstream defined for the current branch.");
+		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",
+			die(_("No remote tracking branch for %s from %s"),
 			    branch->merge[i]->src, branch->remote_name);
 		args[i] = branch->merge[i]->dst;
 	}
@@ -1054,10 +1071,10 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 	}
 	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.");
+			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).");
+			die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists)."));
 	}
 	resolve_undo_clear();
 
@@ -1073,9 +1090,12 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 	if (!allow_fast_forward && fast_forward_only)
 		die(_("You cannot combine --no-ff with --ff-only."));
 
-	if (!argc && !abort_current_merge && default_to_upstream)
-		argc = setup_with_upstream(&argv);
-
+	if (!abort_current_merge) {
+		if (!argc && default_to_upstream)
+			argc = setup_with_upstream(&argv);
+		else if (argc == 1 && !strcmp(argv[0], "-"))
+			argv[0] = "@{-1}";
+	}
 	if (!argc)
 		usage_with_options(builtin_merge_usage,
 			builtin_merge_options);