Fix crashes due to null uuids and fix entity references not serializing

src/main/java/com/minelittlepony/unicopia/ability/magic/spell/PlacementControlSpell.java

@@ -20,12 +20,11 @@ import net.minecraft.registry.RegistryKey;
 import net.minecraft.registry.RegistryKeys;
 import net.minecraft.registry.RegistryWrapper.WrapperLookup;
 import net.minecraft.util.Identifier;
-import net.minecraft.util.Util;
 import net.minecraft.util.math.Vec3d;
 import net.minecraft.world.World;
 
 public class PlacementControlSpell extends AbstractSpell implements OrientedSpell {
-    private final DataTracker.Entry<UUID> placedEntityId = dataTracker.startTracking(TrackableDataType.UUID, Util.NIL_UUID);
+    private final DataTracker.Entry<Optional<UUID>> placedEntityId = dataTracker.startTracking(TrackableDataType.UUID, Optional.empty());
     private final DataTracker.Entry<Optional<RegistryKey<World>>> dimension = dataTracker.startTracking(TrackableDataType.ofRegistryKey(), Optional.empty());
     private final DataTracker.Entry<Optional<Vec3d>> position = dataTracker.startTracking(TrackableDataType.OPTIONAL_VECTOR, Optional.empty());
     private final DataTracker.Entry<Optional<Vec3d>> orientation = dataTracker.startTracking(TrackableDataType.OPTIONAL_VECTOR, Optional.empty());
@@ -83,7 +82,7 @@ public class PlacementControlSpell extends AbstractSpell implements OrientedSpel
     public boolean tick(Caster<?> source, Situation situation) {
         if (!source.isClient()) {
 
-            if (Util.NIL_UUID.equals(placedEntityId.getOrDefault(Util.NIL_UUID))) {
+            if (placedEntityId.get().isEmpty()) {
                 if (dimension.get().isEmpty()) {
                     setDimension(source.asWorld().getRegistryKey());
                 }
@@ -99,7 +98,7 @@ public class PlacementControlSpell extends AbstractSpell implements OrientedSpel
                 entity.updatePositionAndAngles(pos.x, pos.y, pos.z, (float)rot.y, (float)rot.x);
                 entity.getWorld().spawnEntity(entity);
 
-                placedEntityId.set(entity.getUuid());
+                placedEntityId.set(Optional.of(entity.getUuid()));
             } else {
                 if (getConnection(source) == null) {
                     setDead();
@@ -112,8 +111,8 @@ public class PlacementControlSpell extends AbstractSpell implements OrientedSpel
 
     @Nullable
     private Ether.Entry<?> getConnection(Caster<?> source) {
-        return delegate == null || Util.NIL_UUID.equals(placedEntityId.getOrDefault(Util.NIL_UUID)) ? null : getWorld(source)
+        return delegate == null || placedEntityId.get().isEmpty() ? null : getWorld(source)
-                .map(world -> Ether.get(world).get(getDelegate().getTypeAndTraits().type(), placedEntityId.get(), delegate.getUuid()))
+                .map(world -> Ether.get(world).get(getDelegate().getTypeAndTraits().type(), placedEntityId.get().get(), delegate.getUuid()))
                 .orElse(null);
     }
 
@@ -128,17 +127,14 @@ public class PlacementControlSpell extends AbstractSpell implements OrientedSpel
         position.get().ifPresent(pos -> compound.put("position", NbtSerialisable.writeVector(pos)));
         orientation.get().ifPresent(o -> compound.put("orientation", NbtSerialisable.writeVector(o)));
         dimension.get().ifPresent(d -> compound.putString("dimension", d.getValue().toString()));
-        @Nullable UUID placeEntityUuid = placedEntityId.getOrDefault(Util.NIL_UUID);
+        placedEntityId.get().ifPresent(i -> compound.putUuid("placedEntityId", i));
-        if (!Util.NIL_UUID.equals(placeEntityUuid)) {
-            compound.putUuid("placedEntityId", placeEntityUuid);
-        }
     }
 
     @Override
     public void fromNBT(NbtCompound compound, WrapperLookup lookup) {
         super.fromNBT(compound, lookup);
         delegate = Spell.readNbt(compound.getCompound("spell"), lookup);
-        placedEntityId.set(compound.containsUuid("placedEntityId") ? compound.getUuid("placedEntityId") : Util.NIL_UUID);
+        placedEntityId.set(compound.containsUuid("placedEntityId") ? Optional.of(compound.getUuid("placedEntityId")) : Optional.empty());
         position.set(compound.contains("position") ? Optional.of(NbtSerialisable.readVector(compound.getList("position", NbtElement.DOUBLE_TYPE))) : Optional.empty());
         orientation.set(compound.contains("orientation") ? Optional.of(NbtSerialisable.readVector(compound.getList("orientation", NbtElement.DOUBLE_TYPE))) : Optional.empty());
         dimension.set(compound.contains("dimension", NbtElement.STRING_TYPE) ? Optional.ofNullable(Identifier.tryParse(compound.getString("dimension"))).map(id -> RegistryKey.of(RegistryKeys.WORLD, id)) : Optional.empty());

src/main/java/com/minelittlepony/unicopia/ability/magic/spell/effect/PortalSpell.java

@@ -1,5 +1,6 @@
 package com.minelittlepony.unicopia.ability.magic.spell.effect;
 
+import java.util.Optional;
 import java.util.UUID;
 
 import org.jetbrains.annotations.Nullable;
@@ -29,7 +30,6 @@ import net.minecraft.particle.ParticleTypes;
 import net.minecraft.registry.RegistryWrapper.WrapperLookup;
 import net.minecraft.server.network.ServerPlayerEntity;
 import net.minecraft.server.world.ServerWorld;
-import net.minecraft.util.Util;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.math.MathHelper;
 import net.minecraft.util.math.Vec3d;
@@ -43,8 +43,7 @@ public class PortalSpell extends AbstractSpell implements PlacementControlSpell.
             .build();
     private static final Shape PARTICLE_AREA = new Sphere(true, 2, 1, 1, 0);
 
-    @Nullable
+    private final DataTracker.Entry<Optional<UUID>> targetPortalId = dataTracker.startTracking(TrackableDataType.UUID, Optional.empty());
-    private final DataTracker.Entry<UUID> targetPortalId = dataTracker.startTracking(TrackableDataType.UUID, Util.NIL_UUID);
     private final DataTracker.Entry<Float> targetPortalPitch = dataTracker.startTracking(TrackableDataType.FLOAT, 0F);
     private final DataTracker.Entry<Float> targetPortalYaw = dataTracker.startTracking(TrackableDataType.FLOAT, 0F);
     private final EntityReference<Entity> teleportationTarget = dataTracker.startTracking(new EntityReference<>());
@@ -84,11 +83,11 @@ public class PortalSpell extends AbstractSpell implements PlacementControlSpell.
 
     @SuppressWarnings("unchecked")
     private Ether.Entry<PortalSpell> getDestination(Caster<?> source) {
-        return Util.NIL_UUID.equals(targetPortalId.getOrDefault(Util.NIL_UUID)) ? null : getDestinationReference()
+        return targetPortalId.get().flatMap(id -> getDestinationReference()
                 .getTarget()
-                .map(target -> Ether.get(source.asWorld()).get((SpellType<PortalSpell>)getType(), target.uuid(), targetPortalId.get()))
+                .map(target -> Ether.get(source.asWorld()).get((SpellType<PortalSpell>)getType(), target.uuid(), id))
                 .filter(destination -> destination.isClaimedBy(getUuid()))
-                .orElse(null);
+        ).orElse(null);
     }
 
     @Override
@@ -99,10 +98,10 @@ public class PortalSpell extends AbstractSpell implements PlacementControlSpell.
     protected void setDestination(@Nullable Ether.Entry<?> destination) {
         if (destination == null) {
             teleportationTarget.set(null);
-            targetPortalId.set(Util.NIL_UUID);
+            targetPortalId.set(Optional.empty());
         } else {
             teleportationTarget.copyFrom(destination.entity);
-            targetPortalId.set(destination.getSpellId());
+            targetPortalId.set(Optional.of(destination.getSpellId()));
             targetPortalPitch.set(destination.getPitch());
             targetPortalYaw.set(destination.getYaw());
         }
@@ -229,10 +228,7 @@ public class PortalSpell extends AbstractSpell implements PlacementControlSpell.
     @Override
     public void toNBT(NbtCompound compound, WrapperLookup lookup) {
         super.toNBT(compound, lookup);
-        @Nullable UUID otherPortalUuid = targetPortalId.getOrDefault(Util.NIL_UUID);
+        targetPortalId.get().ifPresent(i -> compound.putUuid("targetPortalId", i));
-        if (!Util.NIL_UUID.equals(otherPortalUuid)) {
-            compound.putUuid("targetPortalId", otherPortalUuid);
-        }
         compound.put("teleportationTarget", teleportationTarget.toNBT(lookup));
         compound.putFloat("pitch", getPitch());
         compound.putFloat("yaw", getYaw());
@@ -243,7 +239,7 @@ public class PortalSpell extends AbstractSpell implements PlacementControlSpell.
     @Override
     public void fromNBT(NbtCompound compound, WrapperLookup lookup) {
         super.fromNBT(compound, lookup);
-        targetPortalId.set(compound.containsUuid("targetPortalId") ? compound.getUuid("targetPortalId") : Util.NIL_UUID);
+        targetPortalId.set(compound.containsUuid("targetPortalId") ? Optional.of(compound.getUuid("targetPortalId")) : Optional.empty());
         teleportationTarget.fromNBT(compound.getCompound("teleportationTarget"), lookup);
         pitch.set(compound.getFloat("pitch"));
         yaw.set(compound.getFloat("yaw"));

src/main/java/com/minelittlepony/unicopia/client/render/spell/PortalSpellRenderer.java

@@ -42,10 +42,6 @@ public class PortalSpellRenderer extends SpellRenderer<PortalSpell> {
             return;
         }
 
-        // Fancy portal rendering is disabled for now
-        // Need to fix:
-        // 1. Transparent parts of the sky (because the game sets the clear to (0,0,0,0)
-
         if (caster.asEntity().distanceTo(client.cameraEntity) > 50) {
             return; // don't bother rendering if too far away
         }

src/main/java/com/minelittlepony/unicopia/entity/EntityReference.java

@@ -74,6 +74,7 @@ public class EntityReference<T extends Entity> implements NbtSerialisable, Track
     public void copyFrom(EntityReference<? extends T> other) {
         this.reference = ((EntityReference<T>)other).reference;
         this.directReference = new WeakReference<>(other.directReference.get());
+        dirty = true;
     }
 
     public boolean set(@Nullable T entity) {
@@ -128,7 +129,9 @@ public class EntityReference<T extends Entity> implements NbtSerialisable, Track
 
     @Override
     public void toNBT(NbtCompound tag, WrapperLookup lookup) {
-        getTarget().ifPresent(ref -> EntityValues.CODEC.encode(ref, lookup.getOps(NbtOps.INSTANCE), tag));
+        getTarget().ifPresent(ref -> {
+            EntityValues.CODEC.encodeStart(lookup.getOps(NbtOps.INSTANCE), ref).result().ifPresent(nbt -> tag.copyFrom((NbtCompound)nbt));
+        });
     }
 
     @SuppressWarnings("unchecked")
@@ -160,7 +163,10 @@ public class EntityReference<T extends Entity> implements NbtSerialisable, Track
 
     @Override
     public NbtCompound writeTrackedNbt(WrapperLookup lookup) {
-        return toNBT(lookup);
+        return getTarget()
+                .flatMap(ref -> EntityValues.CODEC.encodeStart(lookup.getOps(NbtOps.INSTANCE), ref).result())
+                .map(NbtCompound.class::cast)
+                .orElseGet(NbtCompound::new);
     }
 
     @Override

src/main/java/com/minelittlepony/unicopia/entity/Living.java

@@ -73,7 +73,6 @@ import net.minecraft.sound.BlockSoundGroup;
 import net.minecraft.sound.SoundCategory;
 import net.minecraft.util.Hand;
 import net.minecraft.util.Identifier;
-import net.minecraft.util.Util;
 import net.minecraft.util.hit.BlockHitResult;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.math.Direction;
@@ -110,7 +109,7 @@ public abstract class Living<T extends LivingEntity> implements Equine<T>, Caste
     protected final DataTrackerManager trackers;
     protected final DataTracker tracker;
 
-    protected final DataTracker.Entry<UUID> carrierId;
+    protected final DataTracker.Entry<Optional<UUID>> carrierId;
 
     protected Living(T entity) {
         this.entity = entity;
@@ -121,7 +120,7 @@ public abstract class Living<T extends LivingEntity> implements Equine<T>, Caste
         this.landedHeuristic = addTicker(new Interactable(entity::isOnGround));
         this.jumpingHeuristic = addTicker(new Interactable(((LivingEntityDuck)entity)::isJumping));
 
-        carrierId = tracker.startTracking(TrackableDataType.UUID, Util.NIL_UUID);
+        carrierId = tracker.startTracking(TrackableDataType.UUID, Optional.empty());
     }
 
     public <Q extends Tickable> Q addTicker(Q tickable) {
@@ -176,16 +175,15 @@ public abstract class Living<T extends LivingEntity> implements Equine<T>, Caste
     }
 
     public Optional<UUID> getCarrierId() {
-        UUID carrierId = this.carrierId.get();
+        return carrierId.get();
-        return carrierId == Util.NIL_UUID ? Optional.empty() : Optional.of(carrierId);
     }
 
     public void setCarrier(UUID carrier) {
-        carrierId.set(carrier == null ? Util.NIL_UUID : carrier);
+        carrierId.set(Optional.ofNullable(carrier));
     }
 
     public void setCarrier(Entity carrier) {
-        setCarrier(carrier == null ? Util.NIL_UUID : carrier.getUuid());
+        setCarrier(carrier == null ? null : carrier.getUuid());
     }
 
     @Nullable

src/main/java/com/minelittlepony/unicopia/network/track/TrackableDataType.java

@@ -32,7 +32,7 @@ public record TrackableDataType<T>(int id, PacketCodec<RegistryByteBuf, TypedVal
     public static final TrackableDataType<Integer> INT = of(Identifier.of("integer"), PacketCodecs.INTEGER);
     public static final TrackableDataType<Float> FLOAT = of(Identifier.of("float"), PacketCodecs.FLOAT);
     public static final TrackableDataType<Boolean> BOOLEAN = of(Identifier.of("boolean"), PacketCodecs.BOOL);
-    public static final TrackableDataType<UUID> UUID = of(Identifier.of("uuid"), Uuids.PACKET_CODEC);
+    public static final TrackableDataType<Optional<UUID>> UUID = of(Identifier.of("uuid"), PacketCodecs.optional(Uuids.PACKET_CODEC));
     public static final TrackableDataType<NbtCompound> NBT = of(Identifier.of("nbt"), PacketCodecs.NBT_COMPOUND);
     public static final TrackableDataType<NbtCompound> COMPRESSED_NBT = of(Identifier.of("compressed_nbt"), PacketCodecs.NBT_COMPOUND);