app/models/punch.rb in punching_bag-0.3.6 vs app/models/punch.rb in punching_bag-0.3.7

@@ -57,10 +57,10 @@
     punches = punchable.punches.by_timeframe(timeframe, average_time).except_for(self)
     punches.combos.first || punches.first
   end
 
   def combine_with(combo)
-    if combo != self
+    if combo && combo != self
       combo.starts_at = starts_at if starts_at < combo.starts_at
       combo.ends_at = ends_at if ends_at > combo.ends_at
       combo.average_time = PunchingBag.average_time(combo, self)
       combo.hits += hits
       self.destroy if combo.save