[Minor] Maillist: Fix checks logic

diff --git a/src/plugins/lua/maillist.lua b/src/plugins/lua/maillist.lua
index 81e046928cc52be21fae7c336a781c38a8de3fa5..c639dc2dc17e5b9738fbbb92f99de15520b01d98 100644 (file)
--- a/src/plugins/lua/maillist.lua
+++ b/src/plugins/lua/maillist.lua
@@ -221,7 +221,7 @@ local function check_generic_list_headers(task)
         lua_util.debugm(N, task, 'has %s header, score = %s', hname, score)
       else
         local score_change = hscore()
-        if score then
+        if score and score_change then
           score = score + score_change
           lua_util.debugm(N, task, 'has %s header, score = %s', hname, score)
         end