diff --git a/src/script/lua_api/l_util.cpp b/src/script/lua_api/l_util.cpp
index 26e2b985c..c26791646 100644
--- a/src/script/lua_api/l_util.cpp
+++ b/src/script/lua_api/l_util.cpp
@@ -398,7 +398,8 @@ int ModApiUtil::l_get_dir_list(lua_State *L)
 {
 	NO_MAP_LOCK_REQUIRED;
 	const char *path = luaL_checkstring(L, 1);
-	short is_dir = lua_isboolean(L, 2) ? lua_toboolean(L, 2) : -1;
+	bool list_all = !lua_isboolean(L, 2); // if its not a boolean list all
+	bool list_dirs = lua_toboolean(L, 2); // true: list dirs, false: list files
 
 	CHECK_SECURE_PATH(L, path, false);
 
@@ -408,7 +409,7 @@ int ModApiUtil::l_get_dir_list(lua_State *L)
 	lua_newtable(L);
 
 	for (size_t i = 0; i < list.size(); i++) {
-		if (is_dir == -1 || is_dir == list[i].dir) {
+		if (list_all || list_dirs == list[i].dir) {
 			lua_pushstring(L, list[i].name.c_str());
 			lua_rawseti(L, -2, ++index);
 		}