bundle: allow the same ref to be given more than once

"git bundle create x master master" used to create a bundle that lists
the same branch (master) twice.  Cloning from such a bundle resulted in
a needless warning "warning: Duplicated ref: refs/remotes/origin/master".

Signed-off-by: Junio C Hamano <gitster@pobox.com>

bundle.c

@@ -240,6 +240,8 @@ int create_bundle(struct bundle_header *header, const char *path,
 		return error("unrecognized argument: %s'", argv[i]);
 	}
 
+	object_array_remove_duplicates(&revs.pending);
+
 	for (i = 0; i < revs.pending.nr; i++) {
 		struct object_array_entry *e = revs.pending.objects + i;
 		unsigned char sha1[20];

object.c

@@ -268,3 +268,22 @@ void add_object_array_with_mode(struct object *obj, const char *name, struct obj
 	objects[nr].mode = mode;
 	array->nr = ++nr;
 }
+
+void object_array_remove_duplicates(struct object_array *array)
+{
+	int ref, src, dst;
+	struct object_array_entry *objects = array->objects;
+
+	for (ref = 0; ref < array->nr - 1; ref++) {
+		for (src = ref + 1, dst = src;
+		     src < array->nr;
+		     src++) {
+			if (!strcmp(objects[ref].name, objects[src].name))
+				continue;
+			if (src != dst)
+				objects[dst] = objects[src];
+			dst++;
+		}
+		array->nr = dst;
+	}
+}

object.h

@@ -71,5 +71,6 @@ int object_list_contains(struct object_list *list, struct object *obj);
 /* Object array handling .. */
 void add_object_array(struct object *obj, const char *name, struct object_array *array);
 void add_object_array_with_mode(struct object *obj, const char *name, struct object_array *array, unsigned mode);
+void object_array_remove_duplicates(struct object_array *);
 
 #endif /* OBJECT_H */

t/t5701-clone-local.sh

@@ -11,7 +11,7 @@ test_expect_success 'preparing origin repository' '
 	git clone --bare . x &&
 	test "$(GIT_CONFIG=a.git/config git config --bool core.bare)" = true &&
 	test "$(GIT_CONFIG=x/config git config --bool core.bare)" = true
-	git bundle create b1.bundle master HEAD &&
+	git bundle create b1.bundle --all &&
 	git bundle create b2.bundle master &&
 	mkdir dir &&
 	cp b1.bundle dir/b3