Fix so each players opponents are cached in view

forge-game/src/main/java/forge/game/player/Player.java

@@ -274,6 +274,10 @@ public class Player extends GameEntity implements Comparable<Player> {
         return result;
     }
 
+    public void updateOpponentsForView() {
+        view.updateOpponents(this);
+    }
+
     //get single opponent for player if only one, otherwise returns null
     //meant to be used after game ends for the sake of achievements
     public Player getSingleOpponent() {

forge-game/src/main/java/forge/game/player/PlayerView.java

@@ -18,6 +18,7 @@ import forge.game.zone.PlayerZone;
 import forge.game.zone.ZoneType;
 import forge.trackable.TrackableCollection;
 import forge.trackable.TrackableProperty;
+import forge.util.FCollectionView;
 
 
 public class PlayerView extends GameEntityView {
@@ -49,15 +50,15 @@ public class PlayerView extends GameEntityView {
         set(TrackableProperty.AvatarIndex, p.getLobbyPlayer().getAvatarIndex());
     }
 
-    public Iterable<PlayerView> getOpponents() {
+    public FCollectionView<PlayerView> getOpponents() {
         return get(TrackableProperty.Opponents);
     }
-    private TrackableCollection<PlayerView> getOpponentCollection() {
-        return get(TrackableProperty.Opponents);
+    void updateOpponents(Player p) {
+        set(TrackableProperty.Opponents, PlayerView.getCollection(p.getOpponents()));
     }
 
     public boolean isOpponentOf(final PlayerView other) {
-        return getOpponentCollection().contains(other);
+        return getOpponents().contains(other);
     }
 
     @Override

forge-gui/src/main/java/forge/match/MatchUtil.java

@@ -190,6 +190,11 @@ public class MatchUtil {
             game.subscribeToEvents(playbackControl);
         }
 
+        //ensure opponents set properly
+        for (Player p : sortedPlayers) {
+            p.updateOpponentsForView();
+        }
+
         // It's important to run match in a different thread to allow GUI inputs to be invoked from inside game. 
         // Game is set on pause while gui player takes decisions
         game.getAction().invoke(new Runnable() {