* Fixed provisional game freezing bugs of the show playable cards feature #457 (caused by DelverAbility, OfferingAbility, Rooftop Storm, Omniscience, Aluren).

Mage.Sets/src/mage/sets/bornofthegods/Tromokratis.java

@@ -114,7 +114,7 @@ class CantBeBlockedUnlessAllEffect extends RestrictionEffect {
         // check if all creatures of defender are able to block this permanent
         // permanent.canBlock() can't be used because causing recursive call
         for (Permanent permanent: game.getBattlefield().getAllActivePermanents(filter, blocker.getControllerId(), game)) {
-            if (permanent.isTapped() && !game.getState().getContinuousEffects().asThough(this.getId(), AsThoughEffectType.BLOCK_TAPPED, blocker.getControllerId(), game)) {
+            if (permanent.isTapped() && !game.getState().getContinuousEffects().asThough(this.getId(), AsThoughEffectType.BLOCK_TAPPED, source, blocker.getControllerId(), game)) {
                 return false;
             }
             // check blocker restrictions

Mage.Sets/src/mage/sets/innistrad/RooftopStorm.java

@@ -42,6 +42,7 @@ import mage.players.Player;
 import mage.util.CardUtil;
 
 import java.util.UUID;
+import mage.abilities.ActivatedAbility;
 
 /**
  *
@@ -100,9 +101,10 @@ class RooftopStormCostReductionEffect extends CostModificationEffectImpl {
                 Card sourceCard = game.getCard(spell.getSourceId());
                 if (sourceCard != null && sourceCard.hasSubtype("Zombie")) {
                     Player player = game.getPlayer(spell.getControllerId());
-                    if (player != null && player.chooseUse(Outcome.Benefit, "Pay {0} rather than pay the mana cost for Zombie creature", game)) {
+                    if (player != null && 
+                            (CardUtil.isCheckPlayableMode(spell) || player.chooseUse(Outcome.Benefit, "Pay {0} rather than pay the mana cost for Zombie creature", game))) {
                         spell.getManaCostsToPay().clear();
-                        spell.getManaCostsToPay().addAll(new ManaCostsImpl("{0}"));
+                        spell.getManaCostsToPay().addAll(new ManaCostsImpl<>("{0}"));
                         return true;
                     }
                 }

Mage.Sets/src/mage/sets/magic2013/Omniscience.java

@@ -42,6 +42,7 @@ import mage.game.stack.StackObject;
 import mage.players.Player;
 
 import java.util.UUID;
+import mage.util.CardUtil;
 
 /**
  *
@@ -99,7 +100,8 @@ class OmniscienceEffect extends CostModificationEffectImpl {
                             && !sourceCard.getCardType().contains(CardType.LAND)) {
                         Player player = game.getPlayer(source.getControllerId());
                         String message = "Cast " + sourceCard.getName() + " without paying its mana costs?";
-                        if (player != null && player.chooseUse(outcome, message, game)) {
+                        if (player != null && 
+                                (CardUtil.isCheckPlayableMode(abilityToModify) || player.chooseUse(outcome, message, game))) {
                             return true;
                         }
                     }

Mage.Sets/src/mage/sets/tempest/Aluren.java

@@ -49,6 +49,7 @@ import mage.game.Game;
 import mage.game.stack.Spell;
 import mage.game.stack.StackObject;
 import mage.players.Player;
+import mage.util.CardUtil;
 
 /**
  *
@@ -113,7 +114,8 @@ class AlurenEffect extends CostModificationEffectImpl {
                 if (sourceCard != null && sourceCard.getCardType().contains(CardType.CREATURE) && sourceCard.getManaCost().convertedManaCost() <= 3) {
                     Player player = game.getPlayer(stackObject.getControllerId());
                     String message = "Cast " + sourceCard.getName() + " without paying its mana costs?";
-                    if (player != null && player.chooseUse(outcome, message, game)) {
+                    if (player != null && 
+                            (CardUtil.isCheckPlayableMode(abilityToModify) || player.chooseUse(outcome, message, game))) {
                         return true;
                     }
                 }

Mage/src/mage/abilities/ActivatedAbility.java

@@ -38,4 +38,20 @@ import mage.game.Game;
 public interface ActivatedAbility extends Ability {
 
     boolean canActivate(UUID playerId, Game game);
+    
+    /**
+     * Creates a fresh copy of this activated ability.
+     * 
+     * @return A new copy of this ability.
+     */
+    @Override
+    ActivatedAbility copy();   
+    
+    /**
+     * Set a flag to know, that the ability is only created adn used to check 
+     * what's playbable for the player.
+     */
+    void setCheckPlayableMode();
+    
+    boolean isCheckPlayableMode();
 }

Mage/src/mage/abilities/ActivatedAbilityImpl.java

@@ -53,9 +53,11 @@ public abstract class ActivatedAbilityImpl extends AbilityImpl implements Activa
     protected TimingRule timing = TimingRule.INSTANT;
     protected TargetController mayActivate = TargetController.YOU;
     protected UUID activatorId;
+    protected boolean checkPlayableMode;
 
     protected ActivatedAbilityImpl(AbilityType abilityType, Zone zone) {
         super(abilityType, zone);
+        this.checkPlayableMode = false;
     }
 
     public ActivatedAbilityImpl(ActivatedAbilityImpl ability) {
@@ -63,6 +65,7 @@ public abstract class ActivatedAbilityImpl extends AbilityImpl implements Activa
         timing = ability.timing;
         mayActivate = ability.mayActivate;
         activatorId = ability.activatorId;
+        checkPlayableMode = ability.checkPlayableMode;
     }
 
     public ActivatedAbilityImpl(Zone zone) {
@@ -217,4 +220,14 @@ public abstract class ActivatedAbilityImpl extends AbilityImpl implements Activa
         this.timing = timing;
     }
 
+    @Override
+    public void setCheckPlayableMode() {
+        checkPlayableMode = true;
+    }
+
+    @Override
+    public boolean isCheckPlayableMode() {
+        return checkPlayableMode;
+    }
+    
 }

Mage/src/mage/abilities/SpellAbility.java

@@ -84,8 +84,8 @@ public class SpellAbility extends ActivatedAbilityImpl {
 
     @Override
     public boolean canActivate(UUID playerId, Game game) {
-        if (this.spellCanBeActivatedRegularlyNow(playerId, game) ||
+        if (game.getContinuousEffects().asThough(sourceId, AsThoughEffectType.CAST, this, playerId, game) // check this first to allow Offering in main phase
-                game.getContinuousEffects().asThough(sourceId, AsThoughEffectType.CAST, playerId, game)) {
+                || this.spellCanBeActivatedRegularlyNow(playerId, game)) {
             if (spellAbilityType.equals(SpellAbilityType.SPLIT)) {
                 return false;
             }

Mage/src/mage/abilities/costs/AlternativeCost2Impl.java

@@ -57,7 +57,7 @@ public class AlternativeCost2Impl <T extends AlternativeCost2Impl<T>> extends Co
         if (reminderText != null) {
             this.reminderText = new StringBuilder("<i>").append(reminderText).append("</i>").toString();
         }
-        this.add((Cost) cost);
+        this.add(cost);
     }
 
     public AlternativeCost2Impl(final AlternativeCost2Impl cost) {

Mage/src/mage/abilities/costs/AlternativeCostSourceAbility.java

@@ -28,8 +28,6 @@
 package mage.abilities.costs;
 
 import java.util.Iterator;
-import java.util.LinkedList;
-import java.util.List;
 import mage.abilities.Ability;
 import mage.abilities.SpellAbility;
 import mage.abilities.StaticAbility;

Mage/src/mage/abilities/effects/AsThoughEffect.java

@@ -39,6 +39,7 @@ import mage.game.Game;
  */
 public interface AsThoughEffect extends ContinuousEffect {
 
+    boolean applies(UUID sourceId, Ability affectedAbility, Ability source, Game game);
     boolean applies(UUID sourceId, Ability source, Game game);
     AsThoughEffectType getAsThoughEffectType();
 

Mage/src/mage/abilities/effects/AsThoughEffectImpl.java

@@ -28,10 +28,13 @@
 
 package mage.abilities.effects;
 
+import java.util.UUID;
+import mage.abilities.Ability;
 import mage.constants.AsThoughEffectType;
 import mage.constants.Duration;
 import mage.constants.EffectType;
 import mage.constants.Outcome;
+import mage.game.Game;
 
 /**
  *
@@ -52,6 +55,11 @@ public abstract class AsThoughEffectImpl extends ContinuousEffectImpl implements
         this.type = effect.type;
     }
    
+    @Override
+    public boolean applies(UUID sourceId, Ability affectedAbility, Ability source, Game game) {
+        return applies(sourceId, source, game);
+    }
+
     @Override
     public AsThoughEffectType getAsThoughEffectType() {
         return type;

Mage/src/mage/abilities/effects/ContinuousEffects.java

@@ -420,20 +420,32 @@ public class ContinuousEffects implements Serializable {
     }
 
     public boolean asThough(UUID objectId, AsThoughEffectType type, UUID controllerId, Game game) {
+        return asThough(objectId, type, null, controllerId, game);
+    }
+
+    public boolean asThough(UUID objectId, AsThoughEffectType type, Ability affectedAbility, UUID controllerId, Game game) {
         List<AsThoughEffect> asThoughEffectsList = getApplicableAsThoughEffects(type, game);
         for (AsThoughEffect effect: asThoughEffectsList) {
             HashSet<Ability> abilities = asThoughEffectsMap.get(type).getAbility(effect.getId());
             for (Ability ability : abilities) {
                 if (controllerId.equals(ability.getControllerId())) {
-                    if (effect.applies(objectId, ability, game)) {
+                    if (affectedAbility == null) {
-                        return true;
+                        if (effect.applies(objectId, ability, game)) {
+                            return true;
+                        }                        
+                    } else {
+                        if (effect.applies(objectId, affectedAbility, ability, game)) {
+                            return true;
+                        }
                     }
                 }
             }
         }
         return false;
+        
     }
     
+
     /**
      * Filters out asThough effects that are not active.
      *

Mage/src/mage/abilities/effects/common/cost/CostModificationEffectImpl.java

@@ -32,13 +32,10 @@ import mage.constants.Duration;
 import mage.constants.EffectType;
 import mage.constants.Outcome;
 import mage.abilities.Ability;
-import mage.abilities.SpellAbility;
 import mage.abilities.effects.ContinuousEffectImpl;
 import mage.abilities.effects.CostModificationEffect;
-import mage.cards.Card;
 import mage.constants.CostModificationType;
 import mage.game.Game;
-import mage.game.stack.Spell;
 
 /**
  * Simple implementation of a {@link CostModificationEffect} offering simplified

Mage/src/mage/abilities/keyword/DelveAbility.java

@@ -85,7 +85,7 @@ import mage.util.CardUtil;
         if (!target.canChoose(sourceId, controllerId, game)) {
             return;
         }
-        if (player.chooseUse(Outcome.Detriment, "Delve cards from your graveyard?", game)) {
+        if (!CardUtil.isCheckPlayableMode(ability) && player.chooseUse(Outcome.Detriment, "Delve cards from your graveyard?", game)) {
             player.chooseTarget(Outcome.Detriment, target, ability, game);
             if (target.getTargets().size() > 0) {
                 int adjCost = 0;
@@ -94,11 +94,11 @@ import mage.util.CardUtil;
                     if (card == null) {
                         continue;
                     }
-                    card.moveToExile(null, null, this.getSourceId(), game);
+                    player.moveCardToExileWithInfo(card, null, "", getSourceId(), game, Zone.GRAVEYARD);
                     ++adjCost;
                 }
-                game.informPlayers(new StringBuilder(player.getName()).append(" delved ")
+                game.informPlayers(new StringBuilder("Delve: ").append(player.getName()).append(" exiled ")
-                        .append(adjCost).append(" creature").append(adjCost != 1?"s":"").append(" from his or her graveyard").toString());
+                        .append(adjCost).append(" card").append(adjCost != 1?"s":"").append(" from his or her graveyard").toString());
                 CardUtil.adjustCost((SpellAbility)ability, adjCost);
             }
         }

Mage/src/mage/abilities/keyword/OfferingAbility.java

@@ -128,6 +128,11 @@ class OfferingAsThoughEffect extends AsThoughEffectImpl {
 
     @Override
     public boolean applies(UUID sourceId, Ability source, Game game) {
+        return false;
+    }
+
+    @Override
+    public boolean applies(UUID sourceId, Ability affectedAbility, Ability source, Game game) {
         if (sourceId.equals(source.getSourceId())) {
             Card card = game.getCard(sourceId);
             if (!card.getOwnerId().equals(source.getControllerId())) {
@@ -139,10 +144,7 @@ class OfferingAsThoughEffect extends AsThoughEffectImpl {
                 Object alreadyConfirmed = game.getState().getValue("offering_ok_" + card.getId());
                 game.getState().setValue("offering_" + card.getId(), null);
                 game.getState().setValue("offering_ok_" + card.getId(), null);
-                if (alreadyConfirmed != null) {
+                return alreadyConfirmed != null;
-                    return true;
-                }
-                return false;
             } else {
                 // first call -> remove previous Ids
                 game.getState().setValue("offering_Id_" + card.getId(), null);
@@ -153,7 +155,8 @@ class OfferingAsThoughEffect extends AsThoughEffectImpl {
                 FilterControlledCreaturePermanent filter = ((OfferingAbility) source).getFilter();
                 Card spellToCast = game.getCard(source.getSourceId());
                 Player player = game.getPlayer(source.getControllerId());
-                if (player != null && player.chooseUse(Outcome.Benefit, "Offer a " + filter.getMessage() + " to cast " + spellToCast.getName() + "?", game)) {
+                if (player != null &&  !CardUtil.isCheckPlayableMode(affectedAbility) && 
+                        player.chooseUse(Outcome.Benefit, "Offer a " + filter.getMessage() + " to cast " + spellToCast.getName() + "?", game)) {
                     Target target = new TargetControlledCreaturePermanent(1,1,filter,true);
                     player.chooseTarget(Outcome.Sacrifice, target, source, game);
                     if (!target.isChosen()) {
@@ -185,9 +188,9 @@ class OfferingAsThoughEffect extends AsThoughEffectImpl {
 
 class OfferingCostReductionEffect extends CostModificationEffectImpl {
 
-    private UUID spellAbilityId;
+    private final UUID spellAbilityId;
-    private UUID activationId;
+    private final UUID activationId;
-    private ManaCosts<ManaCost> manaCostsToReduce;
+    private final ManaCosts<ManaCost> manaCostsToReduce;
 
     OfferingCostReductionEffect (UUID spellAbilityId, ManaCosts<ManaCost> manaCostsToReduce, UUID activationId) {
         super(Duration.OneUse, Outcome.Benefit, CostModificationType.REDUCE_COST);

Mage/src/mage/abilities/keyword/ShadowAbility.java

@@ -62,7 +62,7 @@ class ShadowEffect extends RestrictionEffect implements MageSingleton {
     @Override
     public boolean canBeBlocked(Permanent attacker, Permanent blocker, Ability source, Game game) {
         if (blocker.getAbilities().containsKey(ShadowAbility.getInstance().getId())
-                || game.getContinuousEffects().asThough(blocker.getId(), AsThoughEffectType.BLOCK_SHADOW, blocker.getControllerId(), game)) {
+                || game.getContinuousEffects().asThough(blocker.getId(), AsThoughEffectType.BLOCK_SHADOW, source, blocker.getControllerId(), game)) {
             return true;
         }
         return false;

Mage/src/mage/abilities/keyword/SuspendAbility.java

@@ -193,7 +193,7 @@ public class SuspendAbility extends ActivatedAbilityImpl {
         MageObject object = game.getObject(sourceId);
         return (object.getCardType().contains(CardType.INSTANT) ||
                 object.hasAbility(FlashAbility.getInstance().getId(), game) ||
-                game.getContinuousEffects().asThough(sourceId, AsThoughEffectType.CAST, playerId,  game) ||
+                game.getContinuousEffects().asThough(sourceId, AsThoughEffectType.CAST, this, playerId,  game) ||
                 game.canPlaySorcery(playerId));
     }
 

Mage/src/mage/players/ManaPool.java

@@ -118,7 +118,7 @@ public class ManaPool implements Serializable {
 
     // check if any mana can be spend to cast the mana cost of an ability
     private boolean spendAnyMana(Ability ability, Game game) {
-        return game.getContinuousEffects().asThough(ability.getSourceId(), AsThoughEffectType.SPEND_ANY_MANA, ability.getControllerId(), game);
+        return game.getContinuousEffects().asThough(ability.getSourceId(), AsThoughEffectType.SPEND_ANY_MANA, ability, ability.getControllerId(), game);
     }
 
     public int get(ManaType manaType) {

Mage/src/mage/players/PlayerImpl.java

@@ -1834,8 +1834,12 @@ public abstract class PlayerImpl implements Player, Serializable {
     }
 
     protected boolean canPlay(ActivatedAbility ability, ManaOptions available, Game game) {
-        if (!(ability instanceof ManaAbility) && ability.canActivate(playerId, game)) {
+        if (!(ability instanceof ManaAbility)) {
-            Ability copy = ability.copy();
+            ActivatedAbility copy = ability.copy();     
+            copy.setCheckPlayableMode(); // prevents from endless loops for asking player to use effects by checking this mode
+            if (!copy.canActivate(playerId, game)) {
+                return false;
+            }
             game.getContinuousEffects().costModification(copy, game);
 
             Card card = game.getCard(ability.getSourceId());

Mage/src/mage/util/CardUtil.java

@@ -33,6 +33,7 @@ import java.util.UUID;
 
 import mage.Mana;
 import mage.abilities.Ability;
+import mage.abilities.ActivatedAbility;
 import mage.abilities.SpellAbility;
 import mage.abilities.costs.AlternativeCost;
 import mage.abilities.costs.AlternativeCostImpl;
@@ -490,4 +491,17 @@ public class CardUtil {
         }
         return uniqueString.toString();
     }
+    
+    /**
+     * Returns if the ability is used to check which cards
+     * are playable on hand. (Issue #457)
+     * @param ability - ability to check
+     * @return 
+     */
+    public static boolean isCheckPlayableMode(Ability ability) {
+        if (ability instanceof ActivatedAbility) {
+            return ((ActivatedAbility) ability).isCheckPlayableMode();
+        }
+        return false;
+    }
 }