Fix #547 and and #548

The first bug in #548 (and the only issue in #547) was a typo. The second bug was fixed by tracking "friends" of the event types, so we can invalidate everything as needed.

proxy/src/main/java/com/velocitypowered/proxy/event/EventTypeTracker.java

@@ -0,0 +1,41 @@
+package com.velocitypowered.proxy.event;
+
+import com.google.common.collect.ArrayListMultimap;
+import com.google.common.collect.HashMultimap;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ListMultimap;
+import com.google.common.collect.Multimap;
+import com.google.common.reflect.TypeToken;
+import java.util.List;
+import java.util.stream.Collectors;
+
+class EventTypeTracker {
+
+  private final ListMultimap<Class<?>, Class<?>> friends;
+
+  public EventTypeTracker() {
+    this.friends = ArrayListMultimap.create();
+  }
+
+  public List<Class<?>> getFriendsOf(final Class<?> eventType) {
+    if (friends.containsKey(eventType)) {
+      return ImmutableList.copyOf(friends.get(eventType));
+    }
+
+    final List<Class<?>> types = getEventTypes(eventType);
+    for (Class<?> type : types) {
+      if (type == eventType) {
+        continue;
+      }
+
+      friends.put(type, eventType);
+    }
+    return types;
+  }
+
+  private static List<Class<?>> getEventTypes(final Class<?> eventType) {
+    return TypeToken.of(eventType).getTypes().rawTypes().stream()
+        .filter(type -> type != Object.class)
+        .collect(Collectors.toList());
+  }
+}

proxy/src/main/java/com/velocitypowered/proxy/event/VelocityEventManager.java

@@ -99,6 +99,7 @@ public class VelocityEventManager implements EventManager {
   private final ReadWriteLock lock = new ReentrantReadWriteLock();
 
   private final List<CustomHandlerAdapter<?>> handlerAdapters = new ArrayList<>();
+  private final EventTypeTracker eventTypeTracker = new EventTypeTracker();
 
   /**
    * Initializes the Velocity event manager.
@@ -172,15 +173,9 @@ public class VelocityEventManager implements EventManager {
     }
   }
 
-  private static List<Class<?>> getEventTypes(final Class<?> eventType) {
-    return TypeToken.of(eventType).getTypes().rawTypes().stream()
-        .filter(type -> type != Object.class)
-        .collect(Collectors.toList());
-  }
-
   private @Nullable HandlersCache bakeHandlers(final Class<?> eventType) {
     final List<HandlerRegistration> baked = new ArrayList<>();
-    final List<Class<?>> types = getEventTypes(eventType);
+    final List<Class<?>> types = eventTypeTracker.getFriendsOf(eventType);
 
     lock.readLock().lock();
     try {
@@ -336,7 +331,7 @@ public class VelocityEventManager implements EventManager {
     }
     // Invalidate all the affected event subtypes
     handlersCache.invalidateAll(registrations.stream()
-        .flatMap(registration -> getEventTypes(registration.eventType).stream())
+        .flatMap(registration -> eventTypeTracker.getFriendsOf(registration.eventType).stream())
         .distinct()
         .collect(Collectors.toList()));
   }
@@ -407,7 +402,7 @@ public class VelocityEventManager implements EventManager {
     final PluginContainer pluginContainer = pluginManager.ensurePluginContainer(plugin);
     requireNonNull(handler, "handler");
     unregisterIf(registration ->
-        registration.plugin == pluginContainer && registration.handler == handler);
+        registration.plugin == pluginContainer && registration.instance == handler);
   }
 
   @Override
@@ -433,7 +428,7 @@ public class VelocityEventManager implements EventManager {
 
     // Invalidate all the affected event subtypes
     handlersCache.invalidateAll(removed.stream()
-        .flatMap(registration -> getEventTypes(registration.eventType).stream())
+        .flatMap(registration -> eventTypeTracker.getFriendsOf(registration.eventType).stream())
         .distinct()
         .collect(Collectors.toList()));
   }