Improve fake player detection.

src/main/java/com/sk89q/worldguard/bukkit/listener/RegionProtectionListener.java

@@ -38,6 +38,7 @@
 import com.sk89q.worldguard.bukkit.util.Entities;
 import com.sk89q.worldguard.bukkit.util.Events;
 import com.sk89q.worldguard.bukkit.util.Materials;
+import com.sk89q.worldguard.bukkit.util.InteropUtil;
 import com.sk89q.worldguard.domains.Association;
 import com.sk89q.worldguard.protection.association.Associables;
 import com.sk89q.worldguard.protection.association.RegionAssociable;
@@ -122,7 +123,7 @@ private boolean isWhitelisted(Cause cause, World world, boolean pvp) {
             Player player = (Player) rootCause;
             WorldConfiguration config = getWorldConfig(world);
 
-            if (config.fakePlayerBuildOverride && Entities.isFakePlayer(player)) {
+            if (config.fakePlayerBuildOverride && InteropUtil.isFakePlayer(player)) {
                 return true;
             }
 

src/main/java/com/sk89q/worldguard/bukkit/util/Entities.java

@@ -119,18 +119,6 @@ public static Entity getShooter(Entity entity) {
         return entity;
     }
 
-    /**
-     * Return whether the given player is a fake player using the typical
-     * fake player convention of [Mod].
-     *
-     * @param player the player
-     * @return true if a fake player
-     */
-    public static boolean isFakePlayer(Player player) {
-        String name = player.getName();
-        return name.length() >= 3 && name.charAt(0) == '[' && name.charAt(name.length() - 1) == ']';
-    }
-
     /**
      * Test whether an entity is hostile.
      *

src/main/java/com/sk89q/worldguard/bukkit/util/InteropUtil.java

@@ -0,0 +1,116 @@
+/*
+ * WorldGuard, a suite of tools for Minecraft
+ * Copyright (C) sk89q <http://www.sk89q.com>
+ * Copyright (C) WorldGuard team and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published by the
+ * Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.sk89q.worldguard.bukkit.util;
+
+import com.google.common.base.Function;
+import org.bukkit.Bukkit;
+import org.bukkit.entity.Player;
+
+import javax.annotation.Nullable;
+import java.lang.reflect.Method;
+import java.util.UUID;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+public final class InteropUtil {
+
+    @Nullable
+    private static final Class<?> forgeFakePlayerClass;
+    // This UUID is from Minecraft Forge (see FakePlayerFactory)
+    private static final UUID forgeFakePlayerUuid = UUID.fromString("41c82c87-7afb-4024-ba57-13d2c99cae77");
+    private static final PlayerHandleFunction playerHandleFunction;
+
+    static {
+        forgeFakePlayerClass = findClass("net.minecraftforge.common.util.FakePlayer");
+
+        PlayerHandleFunction function;
+        try {
+            function = new PlayerHandleFunction();
+        } catch (Exception e) {
+            function = null;
+        }
+        playerHandleFunction = function;
+    }
+
+    @Nullable
+    private static Class<?> findClass(String name) {
+        try {
+            return Class.forName(name);
+        } catch (Throwable ignored) {
+            return null;
+        }
+    }
+
+    private InteropUtil() {
+    }
+
+    /**
+     * Return whether the given player is a fake player.
+     *
+     * @param player the player
+     * @return true if a fake player
+     */
+    public static boolean isFakePlayer(Player player) {
+        UUID uuid = player.getUniqueId();
+        String name = player.getName();
+
+        if (uuid.equals(forgeFakePlayerUuid)) {
+            return true;
+        }
+
+        if (forgeFakePlayerClass != null && playerHandleFunction != null) {
+            Object handle = playerHandleFunction.apply(player);
+            if (handle != null) {
+                if (forgeFakePlayerClass.isAssignableFrom(handle.getClass())) {
+                    return true;
+                }
+            }
+        }
+
+        if (name.length() >= 3 && name.charAt(0) == '[' && name.charAt(name.length() - 1) == ']') {
+            return true;
+        }
+
+        return false;
+    }
+
+    private static final class PlayerHandleFunction implements Function<Object, Object> {
+        private final Class<?> craftPlayerClass;
+        private final Method getHandleMethod;
+
+        private PlayerHandleFunction() throws NoSuchMethodException, ClassNotFoundException {
+            craftPlayerClass = Class.forName(Bukkit.getServer().getClass().getCanonicalName().replaceAll("CraftServer$", "entity.CraftPlayer"));
+            getHandleMethod = craftPlayerClass.getMethod("getHandle");
+        }
+
+        @Nullable
+        @Override
+        public Object apply(Object o) {
+            if (craftPlayerClass.isAssignableFrom(o.getClass())) {
+                try {
+                    return getHandleMethod.invoke(o);
+                } catch (Throwable ignored) {
+                }
+            }
+
+            return null;
+        }
+    }
+}