Fix session assignment for WooCommerce

src/ZGoBackend.hs

@@ -714,7 +714,9 @@ routes pipe config = do
                               ZGoOrder
                                 Nothing
                                 (oaddress o)
-                                ("WC-" <> (T.pack . show $ o_id o))
+                                (case o_id o of
+                                   Just o' -> "WC-" <> (T.pack . show $ o')
+                                   Nothing -> "")
                                 (parseTimeOrError
                                    True
                                    defaultTimeLocale