[Minor] Deal with non-nil REDIS_NIL in multimap

diff --git a/src/plugins/lua/multimap.lua b/src/plugins/lua/multimap.lua
index b36fe9f794c65a32c778210f2c2c9f55c7bcf1ea..99576a511cb0bd35a636c98b8e0427da7b0c4ec6 100644 (file)
--- a/src/plugins/lua/multimap.lua
+++ b/src/plugins/lua/multimap.lua
@@ -276,7 +276,7 @@ local function multimap_callback(task, rule)
     end
 
     local function redis_map_cb(task, err, data)
-      if not err and data then
+      if not err and type(data) ~= 'userdata' then
         callback(data)
       end
     end