Fix WorldData initialization

src/main/java/appeng/client/AppEngClient.java

@@ -13,6 +13,7 @@ import appeng.core.AppEng;
 import appeng.core.AppEngBase;
 import appeng.core.features.registries.PartModels;
 import appeng.core.sync.network.ClientNetworkHandler;
+import appeng.core.worlddata.WorldData;
 import appeng.entity.*;
 import appeng.hooks.ClientTickHandler;
 import appeng.util.Platform;
@@ -22,6 +23,7 @@ import net.fabricmc.fabric.api.client.model.ModelLoadingRegistry;
 import net.fabricmc.fabric.api.client.particle.v1.ParticleFactoryRegistry;
 import net.fabricmc.fabric.api.client.rendereregistry.v1.EntityRendererRegistry;
 import net.fabricmc.fabric.api.event.client.ClientSpriteRegistryCallback;
+import net.fabricmc.fabric.api.event.lifecycle.v1.ServerLifecycleEvents;
 import net.minecraft.client.MinecraftClient;
 import net.minecraft.client.render.entity.ItemEntityRenderer;
 import net.minecraft.client.render.model.BakedModel;
@@ -69,6 +71,12 @@ public final class AppEngClient extends AppEngBase {
         registerEntityRenderers();
         registerItemColors();
         registerTextures();
+
+        // On the client, we'll register for server startup/shutdown to properly setup WorldData
+        // each time the integrated server starts&stops
+        ServerLifecycleEvents.SERVER_STARTED.register(WorldData::onServerStarting);
+        ServerLifecycleEvents.SERVER_STOPPING.register(server -> WorldData.instance().onServerStopping());
+        ServerLifecycleEvents.SERVER_STOPPED.register(server -> WorldData.instance().onServerStoppped());
     }
 
     @Override

src/main/java/appeng/core/api/ApiGrid.java

@@ -18,6 +18,9 @@
 
 package appeng.core.api;
 
+import appeng.api.util.AEPartLocation;
+import appeng.me.GridConnection;
+import appeng.me.GridNode;
 import com.google.common.base.Preconditions;
 
 import appeng.api.exceptions.FailedConnectionException;
@@ -42,8 +45,7 @@ public class ApiGrid implements IGridHelper {
             throw new IllegalStateException("Grid features for " + blk + " are server side only.");
         }
 
-        // FIXME FABRIC return new GridNode(blk);
-        throw new IllegalStateException();
+        return new GridNode(blk);
     }
 
     @Override
@@ -51,8 +53,7 @@ public class ApiGrid implements IGridHelper {
         Preconditions.checkNotNull(a);
         Preconditions.checkNotNull(b);
 
-        // FIXME FABRIC return GridConnection.create(a, b, AEPartLocation.INTERNAL);
-        throw new IllegalStateException();
+        return GridConnection.create(a, b, AEPartLocation.INTERNAL);
     }
 
 }

src/main/java/appeng/server/AppEngServer.java

@@ -6,7 +6,9 @@ import appeng.client.ActionKey;
 import appeng.client.EffectType;
 import appeng.core.AppEngBase;
 import appeng.core.sync.network.ServerNetworkHandler;
+import appeng.core.worlddata.WorldData;
 import appeng.hooks.TickHandler;
+import net.fabricmc.fabric.api.event.lifecycle.v1.ServerLifecycleEvents;
 import net.fabricmc.fabric.api.server.PlayerStream;
 import net.minecraft.block.entity.BlockEntity;
 import net.minecraft.client.util.InputUtil;
@@ -32,6 +34,19 @@ public final class AppEngServer extends AppEngBase {
         this.server = server;
         this.networkHandler = new ServerNetworkHandler();
         this.tickHandler = new TickHandler();
+
+        // For a dedicated server, the lifecycle of WorldData is much simpler
+        WorldData.onServerStarting(server);
+        ServerLifecycleEvents.SERVER_STOPPING.register(s -> onServerStopping());
+        ServerLifecycleEvents.SERVER_STOPPED.register(s -> onServerStopped());
+    }
+
+    private void onServerStopping() {
+        WorldData.instance().onServerStopping();
+    }
+
+    private void onServerStopped() {
+        WorldData.instance().onServerStoppped();
     }
 
     @Override