Use default value to set missing value via depends
fields.depends set None for missing values. But when we instantiate a record and call a method decorated with depends, some field may be set to None which will be used when saved.
This happens for example with ShipmentOut._sync_outgoing_move a Move is instantiated and on_change_with_unit_price_required is called. But if the stock_consignment is activated, it adds a depend to the field state. So the state is set to None which makes the save failing because the state value must be draft or staging on creation (and it is required).
So for me the depends decorator should use the default value of the field if there is one (which mimic the ModelSQL.create behavior).