Add automatic fallback config migration

Author: ZsoltMolnarrr

src/main/java/net/bettercombat/BetterCombat.java

@@ -17,8 +17,9 @@
 public class BetterCombat implements ModInitializer {
     public static final String MODID = "bettercombat";
     public static ServerConfig config;
+    private static FallbackConfig fallbackDefault = FallbackConfig.createDefault();
     public static ConfigManager<FallbackConfig> fallbackConfig = new ConfigManager<FallbackConfig>
-            ("fallback_compatibility", FallbackConfig.createDefault())
+            ("fallback_compatibility", fallbackDefault)
             .builder()
             .setDirectory(MODID)
             .sanitize(true)
@@ -29,8 +30,8 @@ public void onInitialize() {
         AutoConfig.register(ServerConfigWrapper.class, PartitioningSerializer.wrap(JanksonConfigSerializer::new));
         // Intuitive way to load a config :)
         config = AutoConfig.getConfigHolder(ServerConfigWrapper.class).getConfig().server;
+        loadFallbackConfig();
 
-        fallbackConfig.refresh();
         ServerNetwork.initializeHandlers();
         ServerLifecycleEvents.SERVER_STARTED.register((minecraftServer) -> {
             WeaponRegistry.loadAttributes(minecraftServer.getResourceManager());
@@ -41,4 +42,12 @@ public void onInitialize() {
         });
         SoundHelper.registerSounds();
     }
+
+    private void loadFallbackConfig() {
+        fallbackConfig.load();
+        if (fallbackConfig.currentConfig.schema_version < fallbackDefault.schema_version) {
+            fallbackConfig.currentConfig = FallbackConfig.migrate(fallbackConfig.currentConfig, FallbackConfig.createDefault());
+        }
+        fallbackConfig.save();
+    }
 }

src/main/java/net/bettercombat/config/FallbackConfig.java

@@ -1,6 +1,7 @@
 package net.bettercombat.config;
 
 public class FallbackConfig {
+    public int schema_version;
     public String blacklist_item_id_regex;
     public CompatibilitySpecifier[] fallback_compatibility;
 
@@ -18,6 +19,7 @@ public CompatibilitySpecifier(String item_id_regex, String weapon_attributes) {
 
     public static FallbackConfig createDefault() {
         var object = new FallbackConfig();
+        object.schema_version = 1;
         object.blacklist_item_id_regex = "pickaxe";
         object.fallback_compatibility = new CompatibilitySpecifier[] {
                 new CompatibilitySpecifier(
@@ -80,4 +82,9 @@ public static FallbackConfig createDefault() {
         };
         return object;
     }
+
+    public static FallbackConfig migrate(FallbackConfig oldConfig, FallbackConfig newConfig) {
+        newConfig.fallback_compatibility = oldConfig.fallback_compatibility;
+        return newConfig;
+    }
 }