fix Union Driver (#1973)

c99249638.lua

@@ -75,13 +75,17 @@ function c99249638.recost(e,tp,eg,ep,ev,re,r,rp,chk)
 	if chk==0 then return e:GetHandler():IsAbleToRemoveAsCost() end
 	Duel.Remove(e:GetHandler(),POS_FACEUP,REASON_COST)
 end
-function c99249638.refilter(c,tc,tp)
-	return aux.CheckUnionEquip(c,tc) and c:CheckUnionTarget(tc) and c:IsType(TYPE_UNION)
+function c99249638.refilter(c,tc,tp,exclude_modern_count)
+	return aux.CheckUnionEquip(c,tc,exclude_modern_count) and c:CheckUnionTarget(tc) and c:IsType(TYPE_UNION)
 		and c:IsLevelBelow(4) and c:CheckUniqueOnField(tp) and not c:IsForbidden()
 end
 function c99249638.retg(e,tp,eg,ep,ev,re,r,rp,chk)
+	if chk==0 then
 		local c=e:GetHandler()
-	if chk==0 then return c:GetEquipTarget() and Duel.IsExistingMatchingCard(c99249638.refilter,tp,LOCATION_DECK,0,1,nil,c:GetEquipTarget(),tp) end
+		local exct=aux.IsUnionState(e) and 1 or 0
+		return c:GetEquipTarget()
+			and Duel.IsExistingMatchingCard(c99249638.refilter,tp,LOCATION_DECK,0,1,nil,c:GetEquipTarget(),tp,exct)
+	end
 	local tc=e:GetLabelObject()
 	Duel.SetTargetCard(tc)
 	Duel.SetOperationInfo(0,CATEGORY_EQUIP,tc,1,0,0)
@@ -90,9 +94,9 @@ function c99249638.reop(e,tp,eg,ep,ev,re,r,rp)
 	local tc=Duel.GetFirstTarget()
 	if tc:IsFaceup() and tc:IsRelateToEffect(e) and Duel.GetLocationCount(tp,LOCATION_SZONE)>0 then
 		Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_EQUIP)
-		local g=Duel.SelectMatchingCard(tp,c99249638.refilter,tp,LOCATION_DECK,0,1,1,nil,tc,tp)
+		local g=Duel.SelectMatchingCard(tp,c99249638.refilter,tp,LOCATION_DECK,0,1,1,nil,tc,tp,nil)
 		local ec=g:GetFirst()
-		if ec and aux.CheckUnionEquip(ec,tc) and Duel.Equip(tp,ec,tc) then
+		if ec and Duel.Equip(tp,ec,tc) then
 			aux.SetUnionState(ec)
 		end
 	end

utility.lua

@@ -278,10 +278,12 @@ function Auxiliary.SetUnionState(c)
 		c:RegisterEffect(e2)
 	end
 end
-function Auxiliary.CheckUnionEquip(uc,tc)
-	ct1,ct2=tc:GetUnionCount()
-	if uc.old_union then return ct1==0
-	else return ct2==0 end
+--uc: the union monster to be equipped, tc: the target monster
+function Auxiliary.CheckUnionEquip(uc,tc,exclude_modern_count)
+	local modern_count,old_count=tc:GetUnionCount()
+	if exclude_modern_count then modern_count=modern_count-exclude_modern_count end
+	if uc.old_union then return modern_count==0
+	else return old_count==0 end
 end
 --EFFECT_DESTROY_SUBSTITUTE filter for modern union monsters
 function Auxiliary.UnionReplaceFilter(e,re,r,rp)