Add AdvancedShulkerFix and optimize LoginLocationFix

src/main/java/fr/xephi/authme/AuthMe.java

@@ -11,6 +11,7 @@ import fr.xephi.authme.initialization.OnShutdownPlayerSaver;
 import fr.xephi.authme.initialization.OnStartupTasks;
 import fr.xephi.authme.initialization.SettingsProvider;
 import fr.xephi.authme.initialization.TaskCloser;
+import fr.xephi.authme.listener.AdvancedShulkerFixListener;
 import fr.xephi.authme.listener.BedrockAutoLoginListener;
 import fr.xephi.authme.listener.BlockListener;
 import fr.xephi.authme.listener.DoubleLoginFixListener;
@@ -359,6 +360,9 @@ public class AuthMe extends JavaPlugin {
         if (settings.getProperty(SecuritySettings.ANTI_GHOST_PLAYERS)) {
             pluginManager.registerEvents(injector.getSingleton(DoubleLoginFixListener.class), this);
         }
+        if (settings.getProperty(SecuritySettings.ADVANCED_SHULKER_FIX)) {
+            pluginManager.registerEvents(injector.getSingleton(AdvancedShulkerFixListener.class), this);
+        }
     }
 
     /**

src/main/java/fr/xephi/authme/listener/AdvancedShulkerFixListener.java

@@ -0,0 +1,43 @@
+package fr.xephi.authme.listener;
+
+import org.bukkit.block.Block;
+import org.bukkit.block.BlockFace;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.EventPriority;
+import org.bukkit.event.Listener;
+import org.bukkit.event.block.BlockDispenseEvent;
+
+//This fix is only for Minecraft 1.13-
+public class AdvancedShulkerFixListener implements Listener {
+
+    @EventHandler(priority = EventPriority.HIGHEST, ignoreCancelled = true)
+    public void onDispenserActivate(BlockDispenseEvent event) {
+        Block block = event.getBlock();
+        if (block.getFace(block) == BlockFace.DOWN) {
+            //If the block is in y = 0
+            if (block.getY() == 0) {
+                event.setCancelled(true);
+            }
+        }
+        if (block.getFace(block) == BlockFace.UP) {
+            //If the block is in y = 255
+            if (block.getY() == 255) {
+                event.setCancelled(true);
+            }
+        }
+    }
+
+    //This implementation method will be available in my another plugin
+//    @EventHandler(priority = EventPriority.HIGHEST, ignoreCancelled = true)
+//    public void onDispenserBePlaced(BlockPlaceEvent event){
+//        Block block = event.getBlock();
+//        if (block.getType().equals(Material.DISPENSER)){
+//            if (block.getFace(block) == BlockFace.DOWN && block.getY() == 0){
+//                event.setCancelled(true);
+//            }
+//            if (block.getFace(block) == BlockFace.UP && block.getY() == 255){
+//                event.setCancelled(true);
+//            }
+//        }
+//    }
+}

src/main/java/fr/xephi/authme/listener/LoginLocationFixListener.java

@@ -35,7 +35,7 @@ public class LoginLocationFixListener implements Listener {
 
     private static Material materialPortal = Material.matchMaterial("PORTAL");
 
-    private static boolean isChecked = false; // false: unchecked/method not available   true: method is available
+    private static boolean isAvailable; // false: unchecked/method not available   true: method is available
     private final boolean isSmartAsyncTeleport = AuthMe.settings.getProperty(SecuritySettings.SMART_ASYNC_TELEPORT);
     private final boolean isFixPortalStuck = AuthMe.settings.getProperty(SecuritySettings.LOGIN_LOC_FIX_SUB_PORTAL);
     private final boolean isFixGroundStuck = AuthMe.settings.getProperty(SecuritySettings.LOGIN_LOC_FIX_SUB_UNDERGROUND);
@@ -50,15 +50,15 @@ public class LoginLocationFixListener implements Listener {
         }
         try {
             Method getMinHeightMethod = World.class.getMethod("getMinHeight");
-            isChecked = true;
+            isAvailable = true;
         } catch (NoSuchMethodException e) {
-            isChecked = false;
+            isAvailable = false;
         }
     }
 
     private int getMinHeight(World world) {
         //This keeps compatibility of 1.16.x and lower
-        if (isChecked) {
+        if (isAvailable) {
             return world.getMinHeight();
         } else {
             return 0;
@@ -97,10 +97,11 @@ public class LoginLocationFixListener implements Listener {
             Material UpType = JoinLocation.getBlock().getRelative(BlockFace.UP).getType();
             World world = player.getWorld();
             int MaxHeight = world.getMaxHeight();
+            int MinHeight = getMinHeight(world);
             if (!UpType.isOccluding() && !UpType.equals(Material.LAVA)) {
                 return;
             }
-            for (int i = getMinHeight(world); i <= MaxHeight; i++) {
+            for (int i = MinHeight; i <= MaxHeight; i++) {
                 JoinLocation.setY(i);
                 Block JoinBlock = JoinLocation.getBlock();
                 if ((JoinBlock.getRelative(BlockFace.DOWN).getType().isBlock())

src/main/java/fr/xephi/authme/settings/properties/SecuritySettings.java

@@ -35,6 +35,11 @@ public final class SecuritySettings implements SettingsHolder {
     public static final Property<Boolean> ANTI_GHOST_PLAYERS =
         newProperty("3rdPartyFeature.fixes.antiGhostPlayer", false);
 
+    @Comment({"(MC1.13- only)",
+        "Should we fix the shulker crash bug with advanced method?"})
+    public static final Property<Boolean> ADVANCED_SHULKER_FIX =
+        newProperty("3rdPartyFeature.fixes.advancedShulkerFix", true);
+
     @Comment({"Choose the best teleport method by server brand?",
         "(Enable this if you are using Paper)"})
     public static final Property<Boolean> SMART_ASYNC_TELEPORT =