Fix unloaded postbox voiding packages

src/main/java/com/simibubi/create/content/logistics/packagePort/postbox/PostboxBlockEntity.java

@@ -5,8 +5,8 @@
 import com.simibubi.create.AllSoundEvents;
 import com.simibubi.create.Create;
 import com.simibubi.create.content.logistics.packagePort.PackagePortBlockEntity;
+import com.simibubi.create.content.trains.station.GlobalPackagePort;
 import com.simibubi.create.content.trains.station.GlobalStation;
-import com.simibubi.create.content.trains.station.GlobalStation.GlobalPackagePort;
 
 import net.createmod.catnip.animation.LerpedFloat;
 import net.createmod.catnip.animation.LerpedFloat.Chaser;
@@ -91,23 +91,23 @@ protected void read(CompoundTag tag, boolean clientPacket) {
 	}
 
 	@Override
-	public void onChunkUnloaded() {
+	public void setChanged() {
+		saveOfflineBuffer();
+		super.setChanged();
+	}
+
+	private void saveOfflineBuffer() {
 		if (level == null || level.isClientSide)
 			return;
+
 		GlobalStation station = trackedGlobalStation.get();
 		if (station == null)
 			return;
-		if (!station.connectedPorts.containsKey(worldPosition))
-			return;
+
 		GlobalPackagePort globalPackagePort = station.connectedPorts.get(worldPosition);
-		for (int i = 0; i < inventory.getSlots(); i++) {
-			globalPackagePort.offlineBuffer.setStackInSlot(i, inventory.getStackInSlot(i));
-			inventory.setStackInSlot(i, ItemStack.EMPTY);
-		}
+		if (globalPackagePort == null)
+			return;
 
-		globalPackagePort.primed = true;
-		Create.RAILWAYS.markTracksDirty();
-		super.onChunkUnloaded();
+		globalPackagePort.saveOfflineBuffer(inventory);
 	}
-
 }

src/main/java/com/simibubi/create/content/trains/schedule/destination/DeliverPackagesInstruction.java

@@ -16,8 +16,8 @@
 import com.simibubi.create.content.trains.graph.EdgePointType;
 import com.simibubi.create.content.trains.schedule.ScheduleRuntime;
 import com.simibubi.create.content.trains.schedule.ScheduleRuntime.State;
+import com.simibubi.create.content.trains.station.GlobalPackagePort;
 import com.simibubi.create.content.trains.station.GlobalStation;
-import com.simibubi.create.content.trains.station.GlobalStation.GlobalPackagePort;
 import com.simibubi.create.foundation.utility.CreateLang;
 
 import net.createmod.catnip.data.Pair;

src/main/java/com/simibubi/create/content/trains/schedule/destination/FetchPackagesInstruction.java

@@ -17,8 +17,8 @@
 import com.simibubi.create.content.trains.graph.EdgePointType;
 import com.simibubi.create.content.trains.schedule.ScheduleRuntime;
 import com.simibubi.create.content.trains.schedule.ScheduleRuntime.State;
+import com.simibubi.create.content.trains.station.GlobalPackagePort;
 import com.simibubi.create.content.trains.station.GlobalStation;
-import com.simibubi.create.content.trains.station.GlobalStation.GlobalPackagePort;
 import com.simibubi.create.foundation.utility.CreateLang;
 
 import net.createmod.catnip.data.Glob;

src/main/java/com/simibubi/create/content/trains/station/GlobalPackagePort.java

@@ -0,0 +1,43 @@
+package com.simibubi.create.content.trains.station;
+
+import com.simibubi.create.Create;
+
+import net.minecraftforge.items.IItemHandlerModifiable;
+import net.minecraftforge.items.ItemStackHandler;
+
+public class GlobalPackagePort {
+    public String address = "";
+    public ItemStackHandler offlineBuffer = new ItemStackHandler(18);
+    public boolean primed = false;
+    private boolean restoring = false;
+
+    public void restoreOfflineBuffer(IItemHandlerModifiable inventory) {
+        if (!primed) return;
+
+        restoring = true;
+
+        for (int slot = 0; slot < offlineBuffer.getSlots(); slot++) {
+            inventory.setStackInSlot(slot, offlineBuffer.getStackInSlot(slot));
+        }
+
+        restoring = false;
+        primed = false;
+    }
+
+    public void saveOfflineBuffer(IItemHandlerModifiable inventory) {
+        /*
+            * Each time restoreOfflineBuffer changes a slot, the inventory
+            * calls this method. We must filter out those calls to prevent
+            * overwriting later slots which haven't been restored yet, and
+            * to avoid unnecessary work.
+            */
+        if (restoring) return;
+
+        // TODO: Call save method on individual slots rather than iterating
+        for (int slot = 0; slot < inventory.getSlots(); slot++) {
+            offlineBuffer.setStackInSlot(slot, inventory.getStackInSlot(slot));
+        }
+
+        Create.RAILWAYS.markTracksDirty();
+    }
+}

src/main/java/com/simibubi/create/content/trains/station/GlobalStation.java

@@ -11,7 +11,6 @@
 import com.simibubi.create.content.logistics.box.PackageItem;
 import com.simibubi.create.content.logistics.packagePort.postbox.PostboxBlockEntity;
 import com.simibubi.create.content.trains.entity.Carriage;
-import com.simibubi.create.content.trains.entity.CarriageContraptionEntity;
 import com.simibubi.create.content.trains.entity.Train;
 import com.simibubi.create.content.trains.graph.DimensionPalette;
 import com.simibubi.create.content.trains.graph.TrackNode;
@@ -24,7 +23,7 @@
 import net.minecraft.nbt.NbtUtils;
 import net.minecraft.nbt.Tag;
 import net.minecraft.network.FriendlyByteBuf;
-import net.minecraft.server.level.ServerLevel;
+import net.minecraft.server.MinecraftServer;
 import net.minecraft.world.item.ItemStack;
 import net.minecraft.world.level.Level;
 import net.minecraft.world.level.block.entity.BlockEntity;
@@ -33,7 +32,7 @@
 import net.minecraftforge.items.IItemHandler;
 import net.minecraftforge.items.IItemHandlerModifiable;
 import net.minecraftforge.items.ItemHandlerHelper;
-import net.minecraftforge.items.ItemStackHandler;
+import net.minecraftforge.server.ServerLifecycleHooks;
 
 public class GlobalStation extends SingleBlockEntityEdgePoint {
 
@@ -162,27 +161,15 @@ public Train getNearestTrain() {
 		return this.nearestTrain.get();
 	}
 
-	// Package Port integration
-	public static class GlobalPackagePort {
-		public String address = "";
-		public ItemStackHandler offlineBuffer = new ItemStackHandler(18);
-		public boolean primed = false;
-	}
-
 	public void runMailTransfer() {
 		Train train = getPresentTrain();
 		if (train == null || connectedPorts.isEmpty())
 			return;
-		Level level = null;
 
-		for (Carriage carriage : train.carriages) {
-			if (level == null) {
-				CarriageContraptionEntity entity = carriage.anyAvailableEntity();
-				if (entity != null && entity.level() instanceof ServerLevel sl)
-					level = sl.getServer()
-						.getLevel(getBlockEntityDimension());
-			}
+		MinecraftServer server = ServerLifecycleHooks.getCurrentServer();
+		Level level = server.getLevel(getBlockEntityDimension());
 
+		for (Carriage carriage : train.carriages) {
 			IItemHandlerModifiable carriageInventory = carriage.storage.getAllItems();
 			if (carriageInventory == null)
 				continue;
@@ -212,9 +199,14 @@ public void runMailTransfer() {
 						continue;
 
 					postboxInventory.setStackInSlot(slot, ItemStack.EMPTY);
-					Create.RAILWAYS.markTracksDirty();
-					if (box != null)
+
+					if (box == null) {
+						port.primed = true;
+					} else {
 						box.spawnParticles();
+					}
+
+					Create.RAILWAYS.markTracksDirty();
 				}
 			}
 
@@ -243,10 +235,15 @@ public void runMailTransfer() {
 					if (!result.isEmpty())
 						continue;
 
-					Create.RAILWAYS.markTracksDirty();
 					carriageInventory.setStackInSlot(slot, ItemStack.EMPTY);
-					if (box != null)
+
+					if (box == null) {
+						port.primed = true;
+					} else {
 						box.spawnParticles();
+					}
+
+					Create.RAILWAYS.markTracksDirty();
 
 					break;
 				}

src/main/java/com/simibubi/create/content/trains/station/StationBlockEntity.java

@@ -50,7 +50,7 @@
 import com.simibubi.create.content.trains.graph.TrackNodeLocation.DiscoveredLocation;
 import com.simibubi.create.content.trains.schedule.Schedule;
 import com.simibubi.create.content.trains.schedule.ScheduleItem;
-import com.simibubi.create.content.trains.station.GlobalStation.GlobalPackagePort;
+import com.simibubi.create.content.trains.station.GlobalPackagePort;
 import com.simibubi.create.content.trains.track.ITrackBlock;
 import com.simibubi.create.content.trains.track.TrackTargetingBehaviour;
 import com.simibubi.create.foundation.advancement.AllAdvancements;
@@ -985,22 +985,15 @@ public void attachPackagePort(PackagePortBlockEntity ppbe) {
 		if (ppbe instanceof PostboxBlockEntity pbe)
 			pbe.trackedGlobalStation = new WeakReference<>(station);
 
-		if (station.connectedPorts.containsKey(ppbe.getBlockPos()))
-			restoreOfflineBuffer(ppbe, station.connectedPorts.get(ppbe.getBlockPos()));
+		GlobalPackagePort globalPackagePort = station.connectedPorts.get(ppbe.getBlockPos());
 
-		GlobalPackagePort globalPackagePort = new GlobalPackagePort();
-		globalPackagePort.address = ppbe.addressFilter;
-		station.connectedPorts.put(ppbe.getBlockPos(), globalPackagePort);
-	}
-
-	private void restoreOfflineBuffer(PackagePortBlockEntity ppbe, GlobalPackagePort globalPackagePort) {
-		if (!globalPackagePort.primed)
-			return;
-		for (int i = 0; i < globalPackagePort.offlineBuffer.getSlots(); i++) {
-			ppbe.inventory.setStackInSlot(i, globalPackagePort.offlineBuffer.getStackInSlot(i));
-			globalPackagePort.offlineBuffer.setStackInSlot(i, ItemStack.EMPTY);
+		if (globalPackagePort == null) {
+			globalPackagePort = new GlobalPackagePort();
+			globalPackagePort.address = ppbe.addressFilter;
+			station.connectedPorts.put(ppbe.getBlockPos(), globalPackagePort);
+		} else {
+			globalPackagePort.restoreOfflineBuffer(ppbe.inventory);
 		}
-		globalPackagePort.primed = false;
 	}
 
 	public void removePackagePort(PackagePortBlockEntity ppbe) {