player entity value may become invalid due to respawns. This not only fixes #633, but also other cases where player reference is used over time while player respawns and its instance is recycled.

src/main/java/carpet/fakes/ServerPlayerEntityInterface.java

@@ -5,4 +5,7 @@ import carpet.helpers.EntityPlayerActionPack;
 public interface ServerPlayerEntityInterface
 {
     EntityPlayerActionPack getActionPack();
+    void invalidateEntityObjectReference();
+    boolean isInvalidEntityObject();
+
 }