Method undo

forge-game/src/main/java/forge/game/zone/MagicStack.java:195–209

()

        return undoStackOwner == player;
    }
    public final boolean undo() {
        if (undoStack.isEmpty()) { return false; }

        SpellAbility sa = undoStack.peek();
        if (sa.undo()) {
            clearUndoStack(sa);
            new ManaRefundService(sa).refundManaPaid();
        } else {
            clearUndoStack(sa);
            for (Mana pay : sa.getPayingMana()) {
                clearUndoStack(pay.getManaAbility().getSourceSA());
            }
        }
        return true;
    }
    public final void clearUndoStack(SpellAbility sa) {
        if (sa == null) {
            return;