Added safety checking to config.yml

If there is an enum setting, e.g. FLATFILE instead of YAML in a config,
the config will not load and the resulting object will be null. This
adds a check to the main config.yml load and disables the plugin if
there is a problem.

src/main/java/world/bentobox/bentobox/BentoBox.java

@@ -1,5 +1,7 @@
 package world.bentobox.bentobox;
 
+import java.util.Optional;
+
 import org.bukkit.Bukkit;
 import org.bukkit.World;
 import org.bukkit.plugin.PluginManager;
@@ -30,8 +32,6 @@ import world.bentobox.bentobox.managers.RanksManager;
 import world.bentobox.bentobox.managers.SchemsManager;
 import world.bentobox.bentobox.util.heads.HeadGetter;
 
-import java.util.Optional;
-
 /**
  * Main BentoBox class
  * @author tastybento, Poslovitch
@@ -78,6 +78,12 @@ public class BentoBox extends JavaPlugin {
 
         // Load settings from config.yml. This will check if there are any issues with it too.
         settings = new Config<>(this, Settings.class).loadConfigObject("");
+        if (settings == null) {
+            // Settings did no load correctly. Disable plugin.
+            logError("Settings did not load correctly - disabling plugin - please check config.yml");
+            getPluginLoader().disablePlugin(this);
+            return;
+        }
         // Start Database managers
         playersManager = new PlayersManager(this);
         // Check if this plugin is now disabled (due to bad database handling)

src/main/java/world/bentobox/bentobox/Settings.java

@@ -89,7 +89,7 @@ public class Settings implements DataObject {
     @ConfigComment("island unnecessarily.")
     @ConfigEntry(path = "general.allow-obsidian-scooping")
     private boolean allowObsidianScooping = true;
-    
+
     @ConfigComment("Rank required to use a command. e.g., use the invite command. Default is owner rank is required.")
     @ConfigEntry(path = "general.rank-command")
     private Map<String, Integer> rankCommand = new HashMap<>();

src/main/java/world/bentobox/bentobox/database/DatabaseSetup.java

@@ -1,10 +1,10 @@
 package world.bentobox.bentobox.database;
 
 import world.bentobox.bentobox.BentoBox;
-import world.bentobox.bentobox.database.yaml.YamlDatabase;
 import world.bentobox.bentobox.database.json.JSONDatabase;
 import world.bentobox.bentobox.database.mongodb.MongoDBDatabase;
 import world.bentobox.bentobox.database.mysql.MySQLDatabase;
+import world.bentobox.bentobox.database.yaml.YamlDatabase;
 
 public interface DatabaseSetup {
 
@@ -15,8 +15,9 @@ public interface DatabaseSetup {
      * @return Database type
      */
     static DatabaseSetup getDatabase() {
+        BentoBox plugin = BentoBox.getInstance();
         for(DatabaseType type : DatabaseType.values()){
-            if(type == BentoBox.getInstance().getSettings().getDatabaseType()) {
+            if(type == plugin.getSettings().getDatabaseType()) {
                 return type.database;
             }
         }