Modal Double Faces cards fixes:

* Fixed that mdf card can duplicate triggers (example: Skyclave Cleric, see #7187);
 * Fixed that mdf card can raise triggers from another side (example: Kazandu Mammoth, see #7180);

Mage.Tests/src/test/java/org/mage/test/cards/cost/modaldoublefaces/ModalDoubleFacesCardsTest.java

@@ -549,4 +549,48 @@ public class ModalDoubleFacesCardsTest extends CardTestPlayerBase {
 
         assertPermanentCount(playerA, "Balduvian Bears", 2);
     }
+
+    @Test
+    public void test_ETB_OnlySideCardsCanAddAbilitiesToGame() {
+        // possible bug: double triggers (loadCard adds abilities from main + side cards instead side card only)
+        // https://github.com/magefree/mage/issues/7187
+
+        // Skyclave Cleric
+        // creature 1/3
+        // When Skyclave Cleric enters the battlefield, you gain 2 life.
+        addCard(Zone.HAND, playerA, "Skyclave Cleric"); // {1}{W}
+        addCard(Zone.BATTLEFIELD, playerA, "Plains", 2);
+
+        castSpell(1, PhaseStep.PRECOMBAT_MAIN, playerA, "Skyclave Cleric");
+
+        setStrictChooseMode(true);
+        setStopAt(1, PhaseStep.END_TURN);
+        execute();
+        assertAllCommandsUsed();
+
+        assertLife(playerA, 20 + 2); // +2 from 1 etb trigger
+    }
+
+    @Test
+    public void test_ETB_OnlyActualSideCardCanRaiseTriggers() {
+        // possible bug: you play one card but game raise triggers from another side too
+        // https://github.com/magefree/mage/issues/7180
+
+        // Kazandu Mammoth
+        // creature 3/3
+        // Landfall — Whenever a land enters the battlefield under your control, Kazandu Mammoth gets +2/+2 until end of turn.
+        //
+        // Kazandu Valley
+        // land
+        addCard(Zone.HAND, playerA, "Kazandu Mammoth"); // {1}{G}{G}
+
+        // play land, but no landfall triggers from other side
+        playLand(1, PhaseStep.PRECOMBAT_MAIN, playerA, "Kazandu Valley");
+        checkStackSize("no triggers", 1, PhaseStep.PRECOMBAT_MAIN, playerA, 0);
+
+        setStrictChooseMode(true);
+        setStopAt(1, PhaseStep.END_TURN);
+        execute();
+        assertAllCommandsUsed();
+    }
 }

Mage.Tests/src/test/java/org/mage/test/player/TestPlayer.java

@@ -1149,7 +1149,11 @@ public class TestPlayer implements Player {
     }
 
     private void printAbilities(Game game, List<? extends Ability> abilities) {
-        System.out.println("Total abilities: " + (abilities != null ? abilities.size() : 0));
+        printAbilities("Total abilities", game, abilities);
+    }
+
+    private void printAbilities(String info, Game game, List<? extends Ability> abilities) {
+        System.out.println(info + ": " + (abilities != null ? abilities.size() : 0));
         if (abilities == null) {
             return;
         }
@@ -1484,6 +1488,9 @@ public class TestPlayer implements Player {
     }
 
     private void assertStackSize(PlayerAction action, Game game, int needStackSize) {
+        if (game.getStack().size() != needStackSize) {
+            printAbilities("Current stack", game, game.getStack().stream().map(StackObject::getStackAbility).collect(Collectors.toList()));
+        }
         Assert.assertEquals(action.getActionName() + " - stack size must be " + needStackSize + " but is " + game.getStack().size(), needStackSize, game.getStack().size());
     }
 

Mage/src/main/java/mage/game/GameImpl.java

@@ -241,40 +241,43 @@ public abstract class GameImpl implements Game, Serializable {
             if (card instanceof PermanentCard) {
                 card = ((PermanentCard) card).getCard();
             }
+
+            // main card
             card.setOwnerId(ownerId);
-            gameCards.put(card.getId(), card);
+            addCardToState(card);
-            state.addCard(card);
+
+            // parts
             if (card instanceof SplitCard) {
                 // left
                 Card leftCard = ((SplitCard) card).getLeftHalfCard();
                 leftCard.setOwnerId(ownerId);
-                gameCards.put(leftCard.getId(), leftCard);
+                addCardToState(leftCard);
-                state.addCard(leftCard);
                 // right
                 Card rightCard = ((SplitCard) card).getRightHalfCard();
                 rightCard.setOwnerId(ownerId);
-                gameCards.put(rightCard.getId(), rightCard);
+                addCardToState(rightCard);
-                state.addCard(rightCard);
             } else if (card instanceof ModalDoubleFacesCard) {
                 // left
                 Card leftCard = ((ModalDoubleFacesCard) card).getLeftHalfCard();
                 leftCard.setOwnerId(ownerId);
-                gameCards.put(leftCard.getId(), leftCard);
+                addCardToState(leftCard);
-                state.addCard(leftCard);
                 // right
                 Card rightCard = ((ModalDoubleFacesCard) card).getRightHalfCard();
                 rightCard.setOwnerId(ownerId);
-                gameCards.put(rightCard.getId(), rightCard);
+                addCardToState(rightCard);
-                state.addCard(rightCard);
             } else if (card instanceof AdventureCard) {
                 Card spellCard = ((AdventureCard) card).getSpellCard();
                 spellCard.setOwnerId(ownerId);
-                gameCards.put(spellCard.getId(), spellCard);
+                addCardToState(spellCard);
-                state.addCard(spellCard);
             }
         }
     }
 
+    private void addCardToState(Card card) {
+        gameCards.put(card.getId(), card);
+        state.addCard(card);
+    }
+
     @Override
     public Collection<Card> getCards() {
         return gameCards.values();

Mage/src/main/java/mage/game/GameState.java

@@ -614,7 +614,7 @@ public class GameState implements Serializable, Copyable<GameState> {
     }
 
     public void addEffect(ContinuousEffect effect, Ability source) {
-        effects.addEffect(effect, source);
+        addEffect(effect, null, source);
     }
 
     public void addEffect(ContinuousEffect effect, UUID sourceId, Ability source) {
@@ -625,9 +625,17 @@ public class GameState implements Serializable, Copyable<GameState> {
         }
     }
 
-//    public void addMessage(String message) {
+    private void addTrigger(TriggeredAbility ability, MageObject attachedTo) {
-//        this.messages.add(message);
+        addTrigger(ability, null, attachedTo);
-//    }
+    }
+
+    private void addTrigger(TriggeredAbility ability, UUID sourceId, MageObject attachedTo) {
+        if (sourceId == null) {
+            triggers.add(ability, attachedTo);
+        } else {
+            triggers.add(ability, sourceId, attachedTo);
+        }
+    }
 
     /**
      * Returns a list of all players of the game ignoring range or if a player
@@ -839,6 +847,14 @@ public class GameState implements Serializable, Copyable<GameState> {
 
     public void addCard(Card card) {
         setZone(card.getId(), Zone.OUTSIDE);
+
+        // dirty hack to fix double triggers, see https://github.com/magefree/mage/issues/7187
+        // main mdf card don't have attached abilities, only parts contains it
+        if (card instanceof ModalDoubleFacesCard) {
+            return;
+        }
+
+        // add card's abilities to game
         for (Ability ability : card.getAbilities()) {
             addAbility(ability, null, card);
         }
@@ -888,7 +904,7 @@ public class GameState implements Serializable, Copyable<GameState> {
                 }
             }
         } else if (ability instanceof TriggeredAbility) {
-            this.triggers.add((TriggeredAbility) ability, attachedTo);
+            addTrigger((TriggeredAbility) ability, null, attachedTo);
         }
     }
 
@@ -911,8 +927,7 @@ public class GameState implements Serializable, Copyable<GameState> {
                 }
             }
         } else if (ability instanceof TriggeredAbility) {
-            // TODO: add sources for triggers - the same way as in addEffect: sources
+            addTrigger((TriggeredAbility) ability, sourceId, attachedTo);
-            this.triggers.add((TriggeredAbility) ability, sourceId, attachedTo);
         }
 
         List<Watcher> watcherList = new ArrayList<>(ability.getWatchers()); // Workaround to prevent ConcurrentModificationException, not clear to me why this is happening now

Mage/src/main/java/mage/game/ZonesHandler.java

@@ -117,25 +117,57 @@ public final class ZonesHandler {
         Card targetCard = getTargetCard(game, event.getTargetId());
 
         Cards cardsToMove = null; // moving real cards
-        Cards cardsToUpdate = null; // updating all card's parts
+        Map<Zone, Cards> cardsToUpdate = new LinkedHashMap<>(); // updating all card's parts (must be ordered LinkedHashMap)
+        cardsToUpdate.put(toZone, new CardsImpl());
+        cardsToUpdate.put(Zone.OUTSIDE, new CardsImpl());
         // if we're moving a token it shouldn't be put into any zone as an object.
         if (!(targetCard instanceof Permanent) && targetCard != null) {
             if (targetCard instanceof MeldCard) {
                 // meld/group cards must be independent (use can choose order)
                 cardsToMove = ((MeldCard) targetCard).getHalves();
-                cardsToUpdate = cardsToMove;
+                cardsToUpdate.get(toZone).addAll(cardsToMove);
             } else if (targetCard instanceof ModalDoubleFacesCard
                     || targetCard instanceof ModalDoubleFacesCardHalf) {
-                // mdf cards must be moved as single object, but each half must be updated separetly
+                // mdf cards must be moved as single object, but each half must be updated separately
                 ModalDoubleFacesCard mdfCard = (ModalDoubleFacesCard) targetCard.getMainCard();
                 cardsToMove = new CardsImpl(mdfCard);
-                cardsToUpdate = new CardsImpl(mdfCard);
+                cardsToUpdate.get(toZone).add(mdfCard);
-                cardsToUpdate.add(mdfCard.getLeftHalfCard());
+                // example: cast left side
-                cardsToUpdate.add(mdfCard.getRightHalfCard());
+                // result:
+                // * main to battlefield
+                // * left to battlefield
+                // * right to outside (it helps to ignore all triggers and other effects from that card)
+                switch (toZone) {
+                    case STACK:
+                    case BATTLEFIELD:
+                        if (targetCard.getId().equals(mdfCard.getLeftHalfCard().getId())) {
+                            // play left
+                            cardsToUpdate.get(toZone).add(mdfCard.getLeftHalfCard());
+                            cardsToUpdate.get(Zone.OUTSIDE).add(mdfCard.getRightHalfCard());
+                        } else if (targetCard.getId().equals(mdfCard.getRightHalfCard().getId())) {
+                            // play right
+                            cardsToUpdate.get(toZone).add(mdfCard.getRightHalfCard());
+                            cardsToUpdate.get(Zone.OUTSIDE).add(mdfCard.getLeftHalfCard());
+                        } else {
+                            // cast mdf (only on stack)
+                            if (!toZone.equals(Zone.STACK)) {
+                                throw new IllegalStateException("Wrong mdf card move to " + toZone + " in placeInDestinationZone");
+                            }
+                            cardsToUpdate.get(toZone).add(mdfCard.getLeftHalfCard());
+                            cardsToUpdate.get(toZone).add(mdfCard.getRightHalfCard());
+                        }
+                        break;
+                    default:
+                        // move all parts
+                        cardsToUpdate.get(toZone).add(mdfCard.getLeftHalfCard());
+                        cardsToUpdate.get(toZone).add(mdfCard.getRightHalfCard());
+                        break;
+                }
             } else {
                 cardsToMove = new CardsImpl(targetCard);
-                cardsToUpdate = cardsToMove;
+                cardsToUpdate.get(toZone).addAll(cardsToMove);
             }
+
             Player owner = game.getPlayer(targetCard.getOwnerId());
             switch (toZone) {
                 case HAND:
@@ -208,13 +240,13 @@ public final class ZonesHandler {
         game.setZone(event.getTargetId(), event.getToZone());
 
         // update zone in other parts (meld cards, mdf half cards)
-        if (cardsToUpdate != null) {
+        cardsToUpdate.entrySet().forEach(entry -> {
-            for (Card card : cardsToUpdate.getCards(game)) {
+            for (Card card : entry.getValue().getCards(game)) {
                 if (!card.getId().equals(event.getTargetId())) {
-                    game.setZone(card.getId(), event.getToZone());
+                    game.setZone(card.getId(), entry.getKey());
                 }
             }
-        }
+        });
 
         // reset meld status
         if (targetCard instanceof MeldCard) {