Remove subjects from cache when they leave the server

sponge/src/main/java/me/lucko/luckperms/LPSpongePlugin.java

@@ -93,6 +93,7 @@ public class LPSpongePlugin implements LuckPermsPlugin {
     private me.lucko.luckperms.api.Logger log;
     private Importer importer;
     private ConsecutiveExecutor consecutiveExecutor;
+    private LuckPermsService service;
 
     @Listener
     public void onEnable(GamePreInitializationEvent event) {
@@ -121,7 +122,7 @@ public class LPSpongePlugin implements LuckPermsPlugin {
         consecutiveExecutor = new ConsecutiveExecutor(commandManager);
 
         getLog().info("Registering PermissionService...");
-        Sponge.getServiceManager().setProvider(this, PermissionService.class, new LuckPermsService(this));
+        Sponge.getServiceManager().setProvider(this, PermissionService.class, (service = new LuckPermsService(this)));
 
         getLog().info("Registering API...");
         apiProvider = new ApiProvider(this);

sponge/src/main/java/me/lucko/luckperms/SpongeListener.java

@@ -22,6 +22,7 @@
 
 package me.lucko.luckperms;
 
+import me.lucko.luckperms.api.sponge.LuckPermsSubject;
 import me.lucko.luckperms.constants.Message;
 import me.lucko.luckperms.users.User;
 import me.lucko.luckperms.utils.AbstractListener;
@@ -30,6 +31,8 @@ import org.spongepowered.api.event.network.ClientConnectionEvent;
 import org.spongepowered.api.profile.GameProfile;
 import org.spongepowered.api.text.serializer.TextSerializers;
 
+import java.util.Iterator;
+
 @SuppressWarnings("WeakerAccess")
 public class SpongeListener extends AbstractListener {
     private final LPSpongePlugin plugin;
@@ -75,5 +78,12 @@ public class SpongeListener extends AbstractListener {
     @Listener
     public void onClientLeave(ClientConnectionEvent.Disconnect e) {
         onLeave(e.getTargetEntity().getUniqueId());
+        Iterator<LuckPermsSubject> iterator = plugin.getService().getUserSubjects().getCache().iterator();
+        while (iterator.hasNext()) {
+            LuckPermsSubject subject = iterator.next();
+            if (subject.getIdentifier().equalsIgnoreCase(e.getTargetEntity().getUniqueId().toString())) {
+                iterator.remove();
+            }
+        }
     }
 }

sponge/src/main/java/me/lucko/luckperms/api/sponge/collections/UserCollection.java

@@ -23,6 +23,7 @@
 package me.lucko.luckperms.api.sponge.collections;
 
 import lombok.AllArgsConstructor;
+import lombok.Getter;
 import lombok.NonNull;
 import me.lucko.luckperms.api.sponge.LuckPermsService;
 import me.lucko.luckperms.api.sponge.LuckPermsSubject;
@@ -47,6 +48,8 @@ import java.util.stream.Collectors;
 public class UserCollection implements SubjectCollection {
     private final LuckPermsService service;
     private final UserManager manager;
+
+    @Getter
     private final Set<LuckPermsSubject> cache = ConcurrentHashMap.newKeySet();
 
     @Override
@@ -82,6 +85,8 @@ public class UserCollection implements SubjectCollection {
             return subject;
         }
 
+        service.getPlugin().getLog().warn("Couldn't get subject for: " + id);
+
         // What am I meant to do here? What if no user is loaded? Load it? Create it?
         // If I do load/create it, this method should always be called async??.... errr.
         return new SimpleSubject(id, service, this);