util.filters: Ignore filters being added twice (fixes issues on removal)

diff --git a/util/filters.lua b/util/filters.lua
index d24bd33e06b0c74bba0462360757bb49733ce88c..6290e53b1744bf82c7c24a0cdeb6b759aaf12a3c 100644 (file)
--- a/util/filters.lua
+++ b/util/filters.lua
@@ -45,6 +45,8 @@ function add_filter(session, type, callback, priority)
        if not filter_list then
                filter_list = {};
                session.filters[type] = filter_list;
+       elseif filter_list[callback] then
+               return; -- Filter already added
        end
        
        priority = priority or 0;