What is the ruling when a husband says, 'You are divorced, you shall enter the house if God wills'?

Primary text

Divorce does not occur whether the wife enters the house or not when the husband states, 'You are divorced, you shall enter the house if God wills' (Anta taliqun litadkhulina ad-dara in sha'a Allah). If she enters, she has fulfilled what was conditioned upon. If she does not enter, it is known that God did not will it, because if He had willed it, it would have occurred, as whatever God wills comes to pass.