* Added a test for #4659 - it's not reproducable (closes #4659).

Mage.Tests/src/test/java/org/mage/test/rollback/DemonicPactTest.java

@@ -1,8 +1,8 @@
-
 package org.mage.test.rollback;
 
 import mage.constants.PhaseStep;
 import mage.constants.Zone;
+import org.junit.Assert;
 import org.junit.Test;
 import org.mage.test.serverside.base.CardTestPlayerBase;
 
@@ -74,4 +74,54 @@ public class DemonicPactTest extends CardTestPlayerBase {
         assertLife(playerB, 16);
 
     }
+
+    /**
+     * Rollback problem with Pact of Negation etc [cards] #4659
+     *
+     * Potential bug here for [Pact of Negation] and similar cards with 0 cost
+     * and demand to pay or lose the next turn.
+     *
+     * So can you check the following scenario where I think the game is buggy:
+     * an opponent casts pact of negation on my turn, his next turn he requests
+     * a rollback to beginning of his turn -- bingo I'm a winner and he loses
+     * the game. The log says I'm the winner and the opponent lost and that is
+     * immediately after rollback request.
+     */
+    
+    @Test
+    public void testPactOfNegationRollback() {
+        addCard(Zone.HAND, playerA, "Silvercoat Lion", 1);
+        addCard(Zone.BATTLEFIELD, playerA, "Plains", 2);
+
+
+        addCard(Zone.BATTLEFIELD, playerB, "Island", 5);
+        // Counter target spell.
+        // At the beginning of your next upkeep, pay {3}{U}{U}. If you don't, you lose the game.
+        addCard(Zone.HAND, playerB, "Pact of Negation"); // Instant {0}
+
+        castSpell(1, PhaseStep.PRECOMBAT_MAIN, playerA, "Silvercoat Lion");
+        castSpell(1, PhaseStep.PRECOMBAT_MAIN, playerB, "Pact of Negation", "Silvercoat Lion", "Silvercoat Lion");
+
+        setChoice(playerB, "Yes");
+
+        rollbackTurns(2, PhaseStep.PRECOMBAT_MAIN, playerB, 0);
+
+        setStrictChooseMode(true);
+        setStopAt(2, PhaseStep.BEGIN_COMBAT);
+        execute();
+        
+        assertAllCommandsUsed();
+
+
+        assertGraveyardCount(playerA, "Silvercoat Lion", 1);
+        assertGraveyardCount(playerB, "Pact of Negation", 1);
+        
+        Assert.assertTrue("Player A is still in game", playerA.isInGame());
+        Assert.assertTrue("Player B is still in game", playerB.isInGame());
+        
+        assertTappedCount("Island", true,  5); 
+
+
+    }
+    
 }

Mage/src/main/java/mage/abilities/common/delayed/PactDelayedTriggeredAbility.java

@@ -1,4 +1,3 @@
-
 package mage.abilities.common.delayed;
 
 import mage.constants.Outcome;
@@ -19,7 +18,6 @@ public class PactDelayedTriggeredAbility extends DelayedTriggeredAbility {
         super(new PactEffect(cost));
     }
 
-
     public PactDelayedTriggeredAbility(PactDelayedTriggeredAbility ability) {
         super(ability);
     }
@@ -39,8 +37,6 @@ public class PactDelayedTriggeredAbility extends DelayedTriggeredAbility {
         return game.isActivePlayer(this.getControllerId());
     }
 
-    
-
     @Override
     public String getRule() {
         return "At the beginning of your next upkeep " + modes.getText();
@@ -49,8 +45,7 @@ public class PactDelayedTriggeredAbility extends DelayedTriggeredAbility {
 
 class PactEffect extends OneShotEffect {
 
-    private ManaCosts cost;
+    private final ManaCosts cost;
-
 
     public PactEffect(ManaCosts cost) {
         super(Outcome.Neutral);
@@ -60,7 +55,7 @@ class PactEffect extends OneShotEffect {
 
     public PactEffect(final PactEffect effect) {
         super(effect);
-        this.cost = effect.cost;
+        this.cost = effect.cost.copy();
     }
 
     @Override
@@ -71,10 +66,10 @@ class PactEffect extends OneShotEffect {
     @Override
     public boolean apply(Game game, Ability source) {
         Player player = game.getPlayer(source.getControllerId());
-        if (player != null) { 
+        if (player != null) {
-            if (player.chooseUse(Outcome.Benefit, "Pay " + cost.getText()  + '?', source, game)) {
+            if (player.chooseUse(Outcome.Benefit, "Pay " + cost.getText() + '?', source, game)) {
                 cost.clearPaid();
-                if (cost.pay(source, game, source.getSourceId(), source.getControllerId(), false, null)){
+                if (cost.pay(source, game, source.getSourceId(), source.getControllerId(), false, null)) {
                     return true;
                 }
             }
@@ -83,7 +78,4 @@ class PactEffect extends OneShotEffect {
         }
         return false;
     }
-
-    
-
 }