hackfest : library widget fix fatal error

library/Class/FilterSettings.php

@@ -72,8 +72,14 @@ class Class_FilterSettings extends Class_Entity {
 
 
   public function getActiveFilters() {
-    return array_merge($this->getDefaultFilters(),
-                       $this->getSelectedFilters());
+    if(!$default_filters = $this->getDefaultFilters())
+      return $this->getSelectedFilters();
+
+    if(!$selected_filters = $this->getSelectedFilters())
+      return $default_filters;
+
+    return array_merge($default_filters,
+                       $selected_filters);
   }
 }
 ?>
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