able to sacrifice a creature to Desecration Demon even when there are no creatures you control

[melvinzhang]

originally from http://www.slightlymagic.net/forum/viewtopic.php?f=82&t=3735&p=167490#p167489

jerichopumpkin wrote:
if you have got no creatures on the battlefield, when you are prompted to choose if sacrifice a creature for Desecration Demon, you can answer "yes", and Desecration Demon still becomes tapped and gets a +1/+1 counter

[ShawnieBoy]

Was checking if the sacrifice option was vaild after already asking the player.

[melvinzhang]

I think that's the wrong fix. The bug is in MagicConditionFactory.HasOptions(targetChoice). Note that the yes/no is asked when the trigger goes on the stack, the sacrifice happens when the effect resolves, between two events, you may have lost all the creatures you control. Thus, it is necessary to check isSatisfied in executeEvent. We should also not retrict the trigger to occur only if the opponent has a creature because you can gain a creature after the trigger goes on the stack and before the trigger resolves.

The bug in MagicConditionFactory.HasOptions(targetChoice) is checking where source.getController has a creature, not if event.getPlayer has a creature. This affects all uses of HasOptions and is rather serious.