Implement data trackers for spells

src/main/java/com/minelittlepony/unicopia/ability/magic/MultiSpellSlot.java

@@ -1,18 +1,25 @@
 package com.minelittlepony.unicopia.ability.magic;
 
+import java.util.Optional;
 import java.util.UUID;
 import java.util.stream.Stream;
 
 import org.jetbrains.annotations.Nullable;
 
+import com.minelittlepony.unicopia.Unicopia;
 import com.minelittlepony.unicopia.ability.magic.spell.Spell;
 import com.minelittlepony.unicopia.ability.magic.spell.SpellReference;
 import com.minelittlepony.unicopia.ability.magic.spell.effect.SpellType;
+import com.minelittlepony.unicopia.network.track.MsgTrackedValues;
 import com.minelittlepony.unicopia.network.track.ObjectTracker;
 import com.minelittlepony.unicopia.network.track.Trackable;
 import com.minelittlepony.unicopia.network.track.TrackableObject;
 import com.minelittlepony.unicopia.util.NbtSerialisable;
+import com.minelittlepony.unicopia.util.serialization.PacketCodec;
+
+import io.netty.buffer.Unpooled;
 import net.minecraft.nbt.NbtCompound;
+import net.minecraft.network.PacketByteBuf;
 
 /**
  * Container for multiple spells
@@ -21,7 +28,7 @@ import net.minecraft.nbt.NbtCompound;
  */
 class MultiSpellSlot implements SpellSlots, NbtSerialisable {
     private final Caster<?> owner;
-    private final ObjectTracker<Entry<?>> tracker;
+    private final ObjectTracker<Entry<Spell>> tracker;
 
     public MultiSpellSlot(Caster<?> owner) {
         this.owner = owner;
@@ -41,7 +48,7 @@ class MultiSpellSlot implements SpellSlots, NbtSerialisable {
     @Override
     public void put(@Nullable Spell effect) {
         if (effect != null) {
-            tracker.add(new Entry<>(owner, effect));
+            tracker.add(effect.getUuid(), new Entry<>(owner, effect));
         }
     }
 
@@ -62,18 +69,32 @@ class MultiSpellSlot implements SpellSlots, NbtSerialisable {
 
     @Override
     public void toNBT(NbtCompound compound) {
-        compound.put("spells", tracker.toNBT());
+        compound.put("spells", NbtSerialisable.writeMap(tracker.entries(), UUID::toString, entry -> entry.spell.toNBT()));
     }
 
     @Override
     public void fromNBT(NbtCompound compound) {
-        tracker.fromNBT(compound.getCompound("spells"));
+        tracker.load(NbtSerialisable.readMap(compound.getCompound("spells"), key -> {
+            try {
+                return UUID.fromString(key);
+            } catch (Throwable ignore) {}
+            return null;
+        }, (key, nbt) -> {
+            try {
+                Entry<Spell> entry = new Entry<>(owner);
+                entry.spell.fromNBT((NbtCompound)nbt);
+                return entry;
+            } catch (Throwable t) {
+                Unicopia.LOGGER.warn("Exception loading tracked object: {}", t.getMessage());
+            }
+            return null;
+        }));
     }
 
-    static final class Entry<T extends Spell> implements TrackableObject {
+    static final class Entry<T extends Spell> implements TrackableObject<Entry<T>> {
         private final Caster<?> owner;
         final SpellReference<T> spell = new SpellReference<>();
-        private Status status = Status.NEW;
+        private boolean hasValue;
 
         public Entry(Caster<?> owner) {
             this.owner = owner;
@@ -99,34 +120,63 @@ class MultiSpellSlot implements SpellSlots, NbtSerialisable {
             }
         }
 
-        @Override
-        public UUID getUuid() {
-            return spell.get().getUuid();
-        }
-
         @Override
         public Status getStatus() {
-            try {
+            boolean hasValue = spell.get() != null;
-                if (spell.get() == null) {
+            if (hasValue != this.hasValue) {
-                    return Status.REMOVED;
+                this.hasValue = hasValue;
-                }
+                return hasValue ? Status.NEW : Status.REMOVED;
-                if (spell.hasDirtySpell()) {
-                    return Status.UPDATED;
-                }
-                return status;
-            } finally {
-                status = Status.DEFAULT;
             }
+
+            return spell.hasDirtySpell() ? Status.UPDATED : Status.DEFAULT;
         }
 
         @Override
-        public NbtCompound toTrackedNbt() {
+        public void readTrackedNbt(NbtCompound nbt) {
+            spell.fromNBT(nbt);
+        }
+
+        @Override
+        public NbtCompound writeTrackedNbt() {
             return spell.toNBT();
         }
 
         @Override
-        public void readTrackedNbt(NbtCompound compound) {
+        public void read(PacketByteBuf buffer) {
-            spell.fromNBT(compound);
+            byte contentType = buffer.readByte();
+            if (contentType == 1) {
+                readTrackedNbt(PacketCodec.COMPRESSED_NBT.read(buffer));
+            } else {
+                T spell = this.spell.get();
+                if (spell != null) {
+                    spell.getDataTracker().load(new MsgTrackedValues.TrackerEntries(buffer));
+                }
+            }
+        }
+
+        @Override
+        public Optional<PacketByteBuf> write(Status status) {
+            if (status != Status.DEFAULT) {
+                PacketByteBuf buffer = new PacketByteBuf(Unpooled.buffer());
+                buffer.writeByte(1);
+                PacketCodec.COMPRESSED_NBT.write(buffer, spell.toNBT());
+                return Optional.of(buffer);
+            }
+            @Nullable T spell = this.spell.get();
+            if (spell == null) {
+                return Optional.empty();
+            }
+            return spell.getDataTracker().getDirtyPairs().map(entries -> {
+                PacketByteBuf buffer = new PacketByteBuf(Unpooled.buffer());
+                buffer.writeByte(0);
+                entries.write(buffer);
+                return buffer;
+            });
+        }
+
+        @Override
+        public void copyTo(Entry<T> destination) {
+            destination.spell.set(spell.get());
         }
     }
 

src/main/java/com/minelittlepony/unicopia/ability/magic/SingleSpellSlot.java

@@ -58,12 +58,12 @@ class SingleSpellSlot implements SpellSlots, NbtSerialisable {
 
     @Override
     public void toNBT(NbtCompound compound) {
-        compound.put("effect", entry.toTrackedNbt());
+        compound.put("effect", entry.spell.toNBT());
     }
 
     @Override
     public void fromNBT(NbtCompound compound) {
-        entry.readTrackedNbt(compound.getCompound("effect"));
+        entry.spell.fromNBT(compound.getCompound("effect"));
     }
 
     @Override

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

@@ -7,15 +7,12 @@ import com.google.common.base.MoreObjects;
 import com.minelittlepony.unicopia.ability.magic.Caster;
 import com.minelittlepony.unicopia.ability.magic.SpellPredicate;
 import com.minelittlepony.unicopia.ability.magic.spell.effect.CustomisedSpellType;
+import com.minelittlepony.unicopia.network.track.DataTracker;
 import com.minelittlepony.unicopia.server.world.Ether;
 
 import net.minecraft.nbt.NbtCompound;
 
 public abstract class AbstractDelegatingSpell implements Spell {
-    private boolean dirty;
-    private boolean hidden;
-    private boolean destroyed;
-
     private UUID uuid = UUID.randomUUID();
 
     private final CustomisedSpellType<?> type;
@@ -25,10 +22,20 @@ public abstract class AbstractDelegatingSpell implements Spell {
         this.type = type;
     }
 
+    public AbstractDelegatingSpell(CustomisedSpellType<?> type, Spell delegate) {
+        this.type = type;
+        this.delegate.set(delegate);
+    }
+
     public final Spell getDelegate() {
         return delegate.get();
     }
 
+    @Override
+    public final DataTracker getDataTracker() {
+        return getOrEmpty().getDataTracker();
+    }
+
     private Spell getOrEmpty() {
         return MoreObjects.firstNonNull(delegate.get(), EmptySpell.INSTANCE);
     }
@@ -73,19 +80,21 @@ public abstract class AbstractDelegatingSpell implements Spell {
         return getOrEmpty().isDying();
     }
 
+    @Deprecated
     @Override
     public boolean isDirty() {
-        return dirty || delegate.hasDirtySpell();
+        return delegate.hasDirtySpell();
     }
 
+    @Deprecated
     @Override
     public void setDirty() {
-        dirty = true;
+        getOrEmpty().setDirty();
     }
 
     @Override
     public boolean isHidden() {
-        return hidden || getOrEmpty().isHidden();
+        return getOrEmpty().isHidden();
     }
 
     @Override
@@ -95,15 +104,6 @@ public abstract class AbstractDelegatingSpell implements Spell {
 
     @Override
     public final void destroy(Caster<?> caster) {
-        if (destroyed) {
-            return;
-        }
-        destroyed = true;
-        setDead();
-        onDestroyed(caster);
-    }
-
-    protected void onDestroyed(Caster<?> caster) {
         if (!caster.isClient()) {
             Ether.get(caster.asWorld()).remove(this, caster);
         }
@@ -123,14 +123,11 @@ public abstract class AbstractDelegatingSpell implements Spell {
     @Override
     public void toNBT(NbtCompound compound) {
         compound.putUuid("uuid", uuid);
-        compound.putBoolean("hidden", hidden);
         compound.put("spell", delegate.toNBT());
     }
 
     @Override
     public void fromNBT(NbtCompound compound) {
-        dirty = false;
-        hidden = compound.getBoolean("hidden");
         if (compound.contains("uuid")) {
             uuid = compound.getUuid("uuid");
         }
@@ -139,6 +136,6 @@ public abstract class AbstractDelegatingSpell implements Spell {
 
     @Override
     public final String toString() {
-        return "Delegate{" + getTypeAndTraits() + "}[uuid=" + uuid + ", destroyed=" + destroyed + ", hidden=" + hidden + "][spell=" + delegate.get() + "]";
+        return "Delegate{" + getTypeAndTraits() + "}[uuid=" + uuid + "][spell=" + delegate.get() + "]";
     }
 }

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

@@ -9,6 +9,8 @@ import com.minelittlepony.unicopia.ability.magic.spell.effect.CustomisedSpellTyp
 import com.minelittlepony.unicopia.ability.magic.spell.trait.Trait;
 import com.minelittlepony.unicopia.entity.behaviour.EntityAppearance;
 import com.minelittlepony.unicopia.entity.player.Pony;
+import com.minelittlepony.unicopia.network.track.DataTracker;
+import com.minelittlepony.unicopia.network.track.TrackableDataType;
 import com.minelittlepony.unicopia.particle.MagicParticleEffect;
 import com.minelittlepony.unicopia.particle.UParticles;
 import net.minecraft.entity.Entity;
@@ -21,6 +23,7 @@ import net.minecraft.nbt.NbtCompound;
  */
 public class DispersableDisguiseSpell extends AbstractDisguiseSpell implements IllusionarySpell {
 
+    private final DataTracker.Entry<Boolean> suppressed = dataTracker.startTracking(TrackableDataType.BOOLEAN, false);
     private int suppressionCounter;
 
     public DispersableDisguiseSpell(CustomisedSpellType<?> type) {
@@ -37,7 +40,7 @@ public class DispersableDisguiseSpell extends AbstractDisguiseSpell implements I
     public void onSuppressed(Caster<?> otherSource, float time) {
         time /= getTraits().getOrDefault(Trait.STRENGTH, 1);
         suppressionCounter = (int)time;
-        setDirty();
+        suppressed.set(true);
     }
 
     @Override
@@ -64,7 +67,9 @@ public class DispersableDisguiseSpell extends AbstractDisguiseSpell implements I
         Entity appearance = getDisguise().getAppearance();
 
         if (isSuppressed()) {
-            suppressionCounter--;
+            if (--suppressionCounter <= 0) {
+                suppressed.set(false);
+            }
 
             owner.setInvisible(false);
             if (source instanceof Pony) {
@@ -92,6 +97,9 @@ public class DispersableDisguiseSpell extends AbstractDisguiseSpell implements I
     public void fromNBT(NbtCompound compound) {
         super.fromNBT(compound);
         suppressionCounter = compound.getInt("suppressionCounter");
+        if (suppressionCounter > 0) {
+            suppressed.set(true);
+        }
     }
 
     @Override

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

@@ -5,6 +5,7 @@ import java.util.UUID;
 import com.minelittlepony.unicopia.ability.magic.Caster;
 import com.minelittlepony.unicopia.ability.magic.spell.effect.CustomisedSpellType;
 import com.minelittlepony.unicopia.ability.magic.spell.effect.SpellType;
+import com.minelittlepony.unicopia.network.track.DataTracker;
 
 import net.minecraft.nbt.NbtCompound;
 import net.minecraft.util.Util;
@@ -74,4 +75,9 @@ public final class EmptySpell implements Spell {
     public String toString() {
         return "EmptySpell{}";
     }
+
+    @Override
+    public DataTracker getDataTracker() {
+        return null;
+    }
 }

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

@@ -7,6 +7,7 @@ import org.jetbrains.annotations.Nullable;
 import com.minelittlepony.unicopia.ability.magic.Caster;
 import com.minelittlepony.unicopia.ability.magic.spell.effect.AbstractSpell;
 import com.minelittlepony.unicopia.ability.magic.spell.effect.CustomisedSpellType;
+import com.minelittlepony.unicopia.ability.magic.spell.effect.SpellType;
 import com.minelittlepony.unicopia.entity.mob.CastSpellEntity;
 import com.minelittlepony.unicopia.server.world.Ether;
 import com.minelittlepony.unicopia.util.NbtSerialisable;
@@ -34,8 +35,8 @@ public class PlacementControlSpell extends AbstractSpell implements OrientedSpel
         super(type);
     }
 
-    PlacementControlSpell(CustomisedSpellType<?> type, Spell delegate) {
+    PlacementControlSpell(Spell delegate) {
-        this(type);
+        this(SpellType.PLACE_CONTROL_SPELL.withTraits(delegate.getTypeAndTraits().traits()));
         this.delegate = delegate;
     }
 
@@ -50,10 +51,12 @@ public class PlacementControlSpell extends AbstractSpell implements OrientedSpel
 
     public void setDimension(RegistryKey<World> dimension) {
         this.dimension = Optional.of(dimension);
+        setDirty();
     }
 
     public void setPosition(Vec3d position) {
         this.position = Optional.of(position);
+        setDirty();
     }
 
     @Override
@@ -98,7 +101,6 @@ public class PlacementControlSpell extends AbstractSpell implements OrientedSpel
             entity.getWorld().spawnEntity(entity);
 
             placedEntityId = entity.getUuid();
-            setDirty();
         }
         return result;
     }

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

@@ -54,7 +54,6 @@ public class RageAbilitySpell extends AbstractSpell {
             ticksExtenguishing++;
             source.playSound(USounds.Vanilla.ENTITY_GENERIC_EXTINGUISH_FIRE, 1);
             source.spawnParticles(ParticleTypes.CLOUD, 12);
-            setDirty();
         } else {
             ticksExtenguishing = 0;
         }
@@ -127,9 +126,6 @@ public class RageAbilitySpell extends AbstractSpell {
 
         age++;
         source.asEntity().setInvulnerable(age < 25);
-
-
-        setDirty();
         return true;
     }
 

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

@@ -13,6 +13,7 @@ import com.minelittlepony.unicopia.ability.magic.Caster;
 import com.minelittlepony.unicopia.ability.magic.SpellPredicate;
 import com.minelittlepony.unicopia.ability.magic.spell.effect.CustomisedSpellType;
 import com.minelittlepony.unicopia.ability.magic.spell.effect.SpellType;
+import com.minelittlepony.unicopia.network.track.DataTracker;
 import com.minelittlepony.unicopia.server.world.Ether;
 import com.minelittlepony.unicopia.util.NbtSerialisable;
 
@@ -30,6 +31,8 @@ public interface Spell extends NbtSerialisable, Affine {
      */
     CustomisedSpellType<?> getTypeAndTraits();
 
+    DataTracker getDataTracker();
+
     default boolean isOf(SpellType<?> type) {
         return getTypeAndTraits().type() == type;
     }
@@ -74,8 +77,15 @@ public interface Spell extends NbtSerialisable, Affine {
     /**
      * Returns true if this effect has changes that need to be sent to the client.
      */
+    @Deprecated
     boolean isDirty();
 
+    /**
+     * Marks this effect as dirty.
+     */
+    @Deprecated
+    void setDirty();
+
     /**
      * Applies this spell to the supplied caster.
      * @param caster    The caster to apply the spell to
@@ -110,11 +120,6 @@ public interface Spell extends NbtSerialisable, Affine {
      */
     void tickDying(Caster<?> caster);
 
-    /**
-     * Marks this effect as dirty.
-     */
-    void setDirty();
-
     boolean isHidden();
 
     void setHidden(boolean hidden);
@@ -128,7 +133,7 @@ public interface Spell extends NbtSerialisable, Affine {
      * Converts this spell into a placeable spell.
      */
     default PlacementControlSpell toPlaceable() {
-        return new PlacementControlSpell(SpellType.PLACE_CONTROL_SPELL.withTraits(), this);
+        return new PlacementControlSpell(this);
     }
 
     /**
@@ -136,7 +141,7 @@ public interface Spell extends NbtSerialisable, Affine {
      * @return
      */
     default ThrowableSpell toThrowable() {
-        return SpellType.THROWN_SPELL.withTraits().create().setSpell(this);
+        return new ThrowableSpell(this);
     }
 
     @Nullable

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

@@ -15,7 +15,6 @@ import net.minecraft.nbt.NbtCompound;
 public final class SpellReference<T extends Spell> implements NbtSerialisable {
     @Nullable
     private transient T spell;
-    private int nbtHash;
 
     @Nullable
     public T get() {
@@ -26,6 +25,7 @@ public final class SpellReference<T extends Spell> implements NbtSerialisable {
         set(spell, null);
     }
 
+    @Deprecated
     public boolean hasDirtySpell() {
         return spell != null && spell.isDirty();
     }
@@ -37,7 +37,6 @@ public final class SpellReference<T extends Spell> implements NbtSerialisable {
         }
         T oldValue = this.spell;
         this.spell = spell;
-        nbtHash = 0;
         if (owner != null && oldValue != null && (spell == null || !oldValue.getUuid().equals(spell.getUuid()))) {
             oldValue.destroy(owner);
         }
@@ -65,19 +64,9 @@ public final class SpellReference<T extends Spell> implements NbtSerialisable {
 
     @Override
     public void fromNBT(NbtCompound compound) {
-        fromNBT(compound, true);
-    }
-
-    public void fromNBT(NbtCompound compound, boolean force) {
-        final int hash = compound.hashCode();
-        if (nbtHash == hash) {
-            return;
-        }
-        nbtHash = hash;
-
         if (spell == null || !Objects.equals(Spell.getUuid(compound), spell.getUuid())) {
             spell = Spell.readNbt(compound);
-        } else if (force || !spell.isDirty()) {
+        } else  {
             spell.fromNBT(compound);
         }
     }

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

@@ -5,6 +5,7 @@ import java.util.Optional;
 import com.minelittlepony.unicopia.USounds;
 import com.minelittlepony.unicopia.ability.magic.Caster;
 import com.minelittlepony.unicopia.ability.magic.spell.effect.CustomisedSpellType;
+import com.minelittlepony.unicopia.ability.magic.spell.effect.SpellType;
 import com.minelittlepony.unicopia.projectile.MagicBeamEntity;
 import com.minelittlepony.unicopia.projectile.MagicProjectileEntity;
 import com.minelittlepony.unicopia.projectile.ProjectileDelegate;
@@ -20,9 +21,8 @@ public final class ThrowableSpell extends AbstractDelegatingSpell implements
         super(type);
     }
 
-    public ThrowableSpell setSpell(Spell spell) {
+    public ThrowableSpell(Spell delegate) {
-        delegate.set(spell);
+        super(SpellType.THROWN_SPELL.withTraits(delegate.getTypeAndTraits().traits()), delegate);
-        return this;
     }
 
     @Override

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

@@ -5,26 +5,34 @@ import java.util.UUID;
 import com.minelittlepony.unicopia.ability.magic.Caster;
 import com.minelittlepony.unicopia.ability.magic.spell.Spell;
 import com.minelittlepony.unicopia.ability.magic.spell.trait.SpellTraits;
+import com.minelittlepony.unicopia.network.track.DataTracker;
+import com.minelittlepony.unicopia.network.track.TrackableDataType;
 import com.minelittlepony.unicopia.server.world.Ether;
 
 import net.minecraft.nbt.NbtCompound;
 
 public abstract class AbstractSpell implements Spell {
 
-    private boolean dead;
+    private UUID uuid = UUID.randomUUID();
-    private boolean dying;
-    private boolean dirty;
-    private boolean hidden;
-    private boolean destroyed;
-
     private final CustomisedSpellType<?> type;
 
-    private UUID uuid = UUID.randomUUID();
+    protected final DataTracker dataTracker = new DataTracker(0);
+
+    private final DataTracker.Entry<Boolean> dead = dataTracker.startTracking(TrackableDataType.BOOLEAN, false);
+    private final DataTracker.Entry<Boolean> dying = dataTracker.startTracking(TrackableDataType.BOOLEAN, false);
+    private boolean dirty;
+    private final DataTracker.Entry<Boolean> hidden = dataTracker.startTracking(TrackableDataType.BOOLEAN, false);
+    private boolean destroyed;
 
     protected AbstractSpell(CustomisedSpellType<?> type) {
         this.type = type;
     }
 
+    @Override
+    public final DataTracker getDataTracker() {
+        return dataTracker;
+    }
+
     @Override
     public final UUID getUuid() {
         return uuid;
@@ -45,25 +53,26 @@ public abstract class AbstractSpell implements Spell {
 
     @Override
     public final void setDead() {
-        dying = true;
+        dying.set(true);
-        setDirty();
     }
 
     @Override
     public final boolean isDead() {
-        return dead;
+        return dead.get();
     }
 
     @Override
     public final boolean isDying() {
-        return dying;
+        return dying.get();
     }
 
+    @Deprecated
     @Override
     public final boolean isDirty() {
         return dirty;
     }
 
+    @Deprecated
     @Override
     public final void setDirty() {
         dirty = true;
@@ -71,17 +80,17 @@ public abstract class AbstractSpell implements Spell {
 
     @Override
     public final boolean isHidden() {
-        return hidden;
+        return hidden.get();
     }
 
     @Override
     public final void setHidden(boolean hidden) {
-        this.hidden = hidden;
+        this.hidden.set(hidden);
     }
 
     @Override
     public void tickDying(Caster<?> caster) {
-        dead = true;
+        dead.set(true);
     }
 
     @Override
@@ -102,9 +111,9 @@ public abstract class AbstractSpell implements Spell {
 
     @Override
     public void toNBT(NbtCompound compound) {
-        compound.putBoolean("dying", dying);
+        compound.putBoolean("dying", dying.get());
-        compound.putBoolean("dead", dead);
+        compound.putBoolean("dead", dead.get());
-        compound.putBoolean("hidden", hidden);
+        compound.putBoolean("hidden", hidden.get());
         compound.putUuid("uuid", uuid);
         compound.put("traits", getTraits().toNbt());
     }
@@ -115,9 +124,9 @@ public abstract class AbstractSpell implements Spell {
         if (compound.containsUuid("uuid")) {
             uuid = compound.getUuid("uuid");
         }
-        dying = compound.getBoolean("dying");
+        dying.set(compound.getBoolean("dying"));
-        dead = compound.getBoolean("dead");
+        dead.set(compound.getBoolean("dead"));
-        hidden = compound.getBoolean("hidden");
+        hidden.set(compound.getBoolean("hidden"));
     }
 
     @Override

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

@@ -42,6 +42,7 @@ public class AttractiveSpell extends ShieldSpell implements HomingSpell, TimedSp
     protected AttractiveSpell(CustomisedSpellType<?> type) {
         super(type);
         timer = new Timer(BASE_DURATION + TimedSpell.getExtraDuration(getTraits()));
+        dataTracker.startTracking(target);
     }
 
     @Override
@@ -57,8 +58,6 @@ public class AttractiveSpell extends ShieldSpell implements HomingSpell, TimedSp
             if (timer.getTicksRemaining() <= 0) {
                 return false;
             }
-
-            setDirty();
         }
 
         target.getOrEmpty(caster.asWorld())

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

@@ -40,8 +40,6 @@ public class AwkwardSpell extends AbstractSpell implements TimedSpell {
             if (timer.getTicksRemaining() <= 0) {
                 return false;
             }
-
-            setDirty();
         }
 
         if (source.isClient()) {

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

@@ -12,6 +12,8 @@ import com.minelittlepony.unicopia.ability.magic.spell.trait.Trait;
 import com.minelittlepony.unicopia.entity.*;
 import com.minelittlepony.unicopia.entity.mob.UEntityAttributes;
 import com.minelittlepony.unicopia.entity.player.Pony;
+import com.minelittlepony.unicopia.network.track.DataTracker;
+import com.minelittlepony.unicopia.network.track.TrackableDataType;
 import com.minelittlepony.unicopia.particle.UParticles;
 import com.minelittlepony.unicopia.projectile.MagicProjectileEntity;
 import com.minelittlepony.unicopia.projectile.ProjectileDelegate;
@@ -55,15 +57,15 @@ public class BubbleSpell extends AbstractSpell implements TimedSpell,
 
     private final Timer timer;
 
-    private int struggles;
-
     private float prevRadius;
-    private float radius;
+    private DataTracker.Entry<Float> radius;
+    private DataTracker.Entry<Integer> struggles;
 
     protected BubbleSpell(CustomisedSpellType<?> type) {
         super(type);
         timer = new Timer(BASE_DURATION + TimedSpell.getExtraDuration(getTraits()));
-        struggles = (int)(getTraits().get(Trait.POWER) * 2);
+        radius = dataTracker.startTracking(TrackableDataType.FLOAT, 0F);
+        struggles = dataTracker.startTracking(TrackableDataType.INT, (int)(getTraits().get(Trait.POWER) * 2));
     }
 
     @Override
@@ -72,7 +74,7 @@ public class BubbleSpell extends AbstractSpell implements TimedSpell,
     }
 
     public float getRadius(float tickDelta) {
-        return MathHelper.lerp(tickDelta, prevRadius, radius);
+        return MathHelper.lerp(tickDelta, prevRadius, radius.get());
     }
 
     @Override
@@ -91,7 +93,7 @@ public class BubbleSpell extends AbstractSpell implements TimedSpell,
                 }
             });
         }
-        radius = Math.max(entity.getHeight(), entity.getWidth()) * 1.2F;
+        radius.set(Math.max(entity.getHeight(), entity.getWidth()) * 1.2F);
         source.playSound(USounds.ENTITY_PLAYER_UNICORN_TELEPORT, 1);
         entity.addVelocity(0, 0.2F * source.getPhysics().getGravitySignum(), 0);
         Living.updateVelocity(entity);
@@ -111,7 +113,7 @@ public class BubbleSpell extends AbstractSpell implements TimedSpell,
 
         boolean done = timer.getTicksRemaining() <= 0;
 
-        source.spawnParticles(source.getOriginVector().add(0, 1, 0), new Sphere(true, radius * (done ? 0.25F : 0.5F)), done ? 13 : 1, pos -> {
+        source.spawnParticles(source.getOriginVector().add(0, 1, 0), new Sphere(true, radius.get() * (done ? 0.25F : 0.5F)), done ? 13 : 1, pos -> {
             source.addParticle(done ? ParticleTypes.BUBBLE_POP : UParticles.BUBBLE, pos, Vec3d.ZERO);
         });
 
@@ -119,8 +121,6 @@ public class BubbleSpell extends AbstractSpell implements TimedSpell,
             return false;
         }
 
-        setDirty();
-
         source.asEntity().addVelocity(
                 MathHelper.sin(source.asEntity().age / 6F) / 50F,
                 MathHelper.sin(source.asEntity().age / 6F) / 50F,
@@ -129,13 +129,14 @@ public class BubbleSpell extends AbstractSpell implements TimedSpell,
 
         source.asEntity().fallDistance = 0;
 
-        prevRadius = radius;
+        prevRadius = radius.get();
 
         if (source instanceof Pony pony && pony.sneakingChanged() && pony.asEntity().isSneaking()) {
-            setDirty();
+            radius.set(radius.get() + 0.5F);
-            radius += 0.5F;
             source.playSound(USounds.SPELL_BUBBLE_DISTURB, 1);
-            if (struggles-- <= 0) {
+            int s = struggles.get() - 1;
+            struggles.set(s);
+            if (s <= 0) {
                 setDead();
                 return false;
             }
@@ -168,16 +169,16 @@ public class BubbleSpell extends AbstractSpell implements TimedSpell,
     @Override
     public void toNBT(NbtCompound compound) {
         super.toNBT(compound);
-        compound.putInt("struggles", struggles);
+        compound.putInt("struggles", struggles.get());
-        compound.putFloat("radius", radius);
+        compound.putFloat("radius", radius.get());
         timer.toNBT(compound);
     }
 
     @Override
     public void fromNBT(NbtCompound compound) {
         super.fromNBT(compound);
-        struggles = compound.getInt("struggles");
+        struggles.set(compound.getInt("struggles"));
-        radius = compound.getFloat("radius");
+        radius.set(compound.getFloat("radius"));
         timer.fromNBT(compound);
     }
 }

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

@@ -17,6 +17,8 @@ import com.minelittlepony.unicopia.ability.magic.spell.trait.Trait;
 import com.minelittlepony.unicopia.entity.Living;
 import com.minelittlepony.unicopia.entity.damage.UDamageTypes;
 import com.minelittlepony.unicopia.entity.mob.CastSpellEntity;
+import com.minelittlepony.unicopia.network.track.DataTracker;
+import com.minelittlepony.unicopia.network.track.TrackableDataType;
 import com.minelittlepony.unicopia.particle.FollowingParticleEffect;
 import com.minelittlepony.unicopia.particle.LightningBoltParticleEffect;
 import com.minelittlepony.unicopia.particle.ParticleUtils;
@@ -56,7 +58,7 @@ public class DarkVortexSpell extends AbstractSpell implements ProjectileDelegate
             .with(Trait.DARKNESS, 100)
             .build();
 
-    private float accumulatedMass = 0;
+    private final DataTracker.Entry<Float> accumulatedMass = this.dataTracker.startTracking(TrackableDataType.FLOAT, 0F);
 
     private final TargetSelecter targetSelecter = new TargetSelecter(this).setFilter(this::isValidTarget).setTargetowner(true).setTargetAllies(true);
 
@@ -70,7 +72,7 @@ public class DarkVortexSpell extends AbstractSpell implements ProjectileDelegate
     // 3. force reaches 0 at distance of drawDropOffRange
 
     private double getMass() {
-        return 0.1F + accumulatedMass / 10F;
+        return 0.1F + accumulatedMass.get() / 10F;
     }
 
     public double getEventHorizonRadius() {
@@ -174,11 +176,12 @@ public class DarkVortexSpell extends AbstractSpell implements ProjectileDelegate
 
     @Override
     public void tickDying(Caster<?> source) {
-        accumulatedMass -= 0.8F;
+        float m = accumulatedMass.get() - 0.8F;
+        accumulatedMass.set(m);
         double mass = getMass() * 0.1;
         double logarithm = 1 - (1D / (1 + (mass * mass)));
         radius.update((float)Math.max(0.1, logarithm * source.asWorld().getGameRules().getInt(UGameRules.MAX_DARK_VORTEX_SIZE)), 200L);
-        if (accumulatedMass < 1) {
+        if (m < 1) {
             super.tickDying(source);
         }
 
@@ -202,7 +205,7 @@ public class DarkVortexSpell extends AbstractSpell implements ProjectileDelegate
 
     @Override
     public boolean isFriendlyTogether(Affine other) {
-        return accumulatedMass < 4;
+        return accumulatedMass.get() < 4;
     }
 
     private boolean isValidTarget(Caster<?> source, Entity entity) {
@@ -274,8 +277,7 @@ public class DarkVortexSpell extends AbstractSpell implements ProjectileDelegate
             double massOfTarget = AttractionUtils.getMass(target);
 
             if (!source.isClient() && massOfTarget != 0) {
-                accumulatedMass += massOfTarget;
+                accumulatedMass.set((float)(accumulatedMass.get() + massOfTarget));
-                setDirty();
             }
 
             target.damage(source.damageOf(UDamageTypes.GAVITY_WELL_RECOIL, source), Integer.MAX_VALUE);
@@ -303,12 +305,12 @@ public class DarkVortexSpell extends AbstractSpell implements ProjectileDelegate
     @Override
     public void toNBT(NbtCompound compound) {
         super.toNBT(compound);
-        compound.putFloat("accumulatedMass", accumulatedMass);
+        compound.putFloat("accumulatedMass", accumulatedMass.get());
     }
 
     @Override
     public void fromNBT(NbtCompound compound) {
         super.fromNBT(compound);
-        accumulatedMass = compound.getFloat("accumulatedMass");
+        accumulatedMass.set(compound.getFloat("accumulatedMass"));
     }
 }

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

@@ -69,8 +69,6 @@ public class FeatherFallSpell extends AbstractSpell implements TimedSpell {
             return false;
         }
 
-        setDirty();
-
         List<Entity> targets = getTargets(caster).toList();
 
         if (targets.isEmpty()) {

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

@@ -63,8 +63,6 @@ public class LightSpell extends AbstractSpell implements TimedSpell, ProjectileD
             return false;
         }
 
-        setDirty();
-
         if (!caster.isClient()) {
             if (lights.isEmpty()) {
                 int size = 2 + caster.asWorld().random.nextInt(2) + (int)(getTraits().get(Trait.LIFE, 10, 20) - 10)/10;
@@ -83,7 +81,6 @@ public class LightSpell extends AbstractSpell implements TimedSpell, ProjectileD
                     entity.getWorld().spawnEntity(entity);
 
                     ref.set(entity);
-                    setDirty();
                 }
             });
         }

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

@@ -35,8 +35,6 @@ public class MimicSpell extends AbstractDisguiseSpell implements HomingSpell, Ti
             return false;
         }
 
-        setDirty();
-
         return super.tick(caster, situation);
     }
 

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

@@ -135,7 +135,6 @@ public class MindSwapSpell extends MimicSpell implements ProjectileDelegate.Enti
                     caster.playSound(USounds.SPELL_MINDSWAP_SWAP, 1);
                 });
                 initialized = true;
-                setDirty();
             }
 
             if (counterpart.isSet()) {
@@ -143,13 +142,12 @@ public class MindSwapSpell extends MimicSpell implements ProjectileDelegate.Enti
 
                 if (other == null) {
                     caster.getOriginatingCaster().asEntity().damage(caster.asWorld().getDamageSources().magic(), Float.MAX_VALUE);
-                    setDead();
+                    destroy(caster);
                     return false;
                 }
 
                 if (!Caster.of(other).get().getSpellSlot().contains(SpellType.MIMIC)) {
-                    onDestroyed(caster);
+                    destroy(caster);
-                    setDead();
                     return false;
                 }
             }
@@ -158,8 +156,7 @@ public class MindSwapSpell extends MimicSpell implements ProjectileDelegate.Enti
                 counterpart.ifPresent(caster.asWorld(), e -> {
                     e.damage(e.getDamageSources().magic(), Float.MAX_VALUE);
                 });
-                onDestroyed(caster);
+                destroy(caster);
-                setDead();
                 return false;
             }
         }

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

@@ -131,7 +131,6 @@ public class NecromancySpell extends AbstractAreaEffectSpell implements Projecti
 
         float additional = source.asWorld().getLocalDifficulty(source.getOrigin()).getLocalDifficulty() + getTraits().get(Trait.CHAOS, 0, 10);
 
-        setDirty();
         if (--spawnCountdown > 0 && !summonedEntities.isEmpty()) {
             return true;
         }
@@ -213,7 +212,6 @@ public class NecromancySpell extends AbstractAreaEffectSpell implements Projecti
 
         source.asWorld().spawnEntity(minion);
         summonedEntities.add(new EntityReference<>(minion));
-        setDirty();
     }
 
     @Override

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

@@ -14,6 +14,8 @@ import com.minelittlepony.unicopia.entity.Living;
 import com.minelittlepony.unicopia.entity.player.Pony;
 import com.minelittlepony.unicopia.network.Channel;
 import com.minelittlepony.unicopia.network.MsgCasterLookRequest;
+import com.minelittlepony.unicopia.network.track.DataTracker;
+import com.minelittlepony.unicopia.network.track.TrackableDataType;
 import com.minelittlepony.unicopia.particle.*;
 import com.minelittlepony.unicopia.server.world.Ether;
 import com.minelittlepony.unicopia.util.shape.*;
@@ -26,6 +28,7 @@ import net.minecraft.network.packet.s2c.play.PositionFlag;
 import net.minecraft.particle.ParticleTypes;
 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;
@@ -40,15 +43,13 @@ public class PortalSpell extends AbstractSpell implements PlacementControlSpell.
     private static final Shape PARTICLE_AREA = new Sphere(true, 2, 1, 1, 0);
 
     @Nullable
-    private UUID targetPortalId;
+    private final DataTracker.Entry<UUID> targetPortalId = dataTracker.startTracking(TrackableDataType.UUID, Util.NIL_UUID);
-    private float targetPortalPitch;
+    private final DataTracker.Entry<Float> targetPortalPitch = dataTracker.startTracking(TrackableDataType.FLOAT, 0F);
-    private float targetPortalYaw;
+    private final DataTracker.Entry<Float> targetPortalYaw = dataTracker.startTracking(TrackableDataType.FLOAT, 0F);
     private final EntityReference<Entity> teleportationTarget = new EntityReference<>();
 
-    private boolean publishedPosition;
+    private final DataTracker.Entry<Float> pitch = dataTracker.startTracking(TrackableDataType.FLOAT, 0F);
-
+    private final DataTracker.Entry<Float> yaw = dataTracker.startTracking(TrackableDataType.FLOAT, 0F);
-    private float pitch;
-    private float yaw;
 
     private Shape particleArea = PARTICLE_AREA;
 
@@ -61,30 +62,30 @@ public class PortalSpell extends AbstractSpell implements PlacementControlSpell.
     }
 
     public float getPitch() {
-        return pitch;
+        return pitch.get();
     }
 
     public float getYaw() {
-        return yaw;
+        return yaw.get();
     }
 
     public float getTargetPitch() {
-        return targetPortalPitch;
+        return targetPortalPitch.get();
     }
 
     public float getTargetYaw() {
-        return targetPortalYaw;
+        return targetPortalYaw.get();
     }
 
     public float getYawDifference() {
-        return MathHelper.wrapDegrees(180 + targetPortalYaw - yaw);
+        return MathHelper.wrapDegrees(180 + getTargetYaw() - getYaw());
     }
 
     @SuppressWarnings("unchecked")
     private Ether.Entry<PortalSpell> getDestination(Caster<?> source) {
-        return targetPortalId == null ? null : getDestinationReference()
+        return Util.NIL_UUID.equals(targetPortalId.get()) ? null : getDestinationReference()
                 .getTarget()
-                .map(target -> Ether.get(source.asWorld()).get((SpellType<PortalSpell>)getType(), target.uuid(), targetPortalId))
+                .map(target -> Ether.get(source.asWorld()).get((SpellType<PortalSpell>)getType(), target.uuid(), targetPortalId.get()))
                 .filter(destination -> destination.isClaimedBy(getUuid()))
                 .orElse(null);
     }
@@ -94,6 +95,18 @@ public class PortalSpell extends AbstractSpell implements PlacementControlSpell.
         return toPlaceable().apply(caster);
     }
 
+    protected void setDestination(@Nullable Ether.Entry<?> destination) {
+        if (destination == null) {
+            teleportationTarget.set(null);
+            targetPortalId.set(Util.NIL_UUID);
+        } else {
+            teleportationTarget.copyFrom(destination.entity);
+            targetPortalId.set(destination.getSpellId());
+            targetPortalPitch.set(destination.getPitch());
+            targetPortalYaw.set(destination.getYaw());
+        }
+    }
+
     @Override
     public boolean tick(Caster<?> source, Situation situation) {
         if (situation == Situation.GROUND) {
@@ -108,9 +121,7 @@ public class PortalSpell extends AbstractSpell implements PlacementControlSpell.
 
                     if (targetEntry == null) {
                         if (teleportationTarget.isSet()) {
-                            teleportationTarget.set(null);
+                            setDestination(null);
-                            targetPortalId = null;
-                            setDirty();
                             source.asWorld().syncWorldEvent(WorldEvents.BLOCK_BROKEN, source.getOrigin(), Block.getRawIdFromState(Blocks.GLASS.getDefaultState()));
                         } else {
                             Ether.get(source.asWorld()).anyMatch(getType(), entry -> {
@@ -119,18 +130,10 @@ public class PortalSpell extends AbstractSpell implements PlacementControlSpell.
                                     ownEntry.claim(entry.getSpellId());
                                     synchronized (entry) {
                                         if (entry.getSpell() instanceof PortalSpell portal) {
-                                            portal.teleportationTarget.copyFrom(ownEntry.entity);
+                                            portal.setDestination(ownEntry);
-                                            portal.targetPortalId = getUuid();
-                                            portal.targetPortalPitch = pitch;
-                                            portal.targetPortalYaw = yaw;
-                                            portal.setDirty();
                                         }
                                     }
-                                    teleportationTarget.copyFrom(entry.entity);
+                                    setDestination(entry);
-                                    targetPortalId = entry.getSpellId();
-                                    targetPortalPitch = entry.getPitch();
-                                    targetPortalYaw = entry.getYaw();
-                                    setDirty();
                                 }
                                 return false;
                             });
@@ -142,8 +145,8 @@ public class PortalSpell extends AbstractSpell implements PlacementControlSpell.
             }
 
             var entry = Ether.get(source.asWorld()).getOrCreate(this, source);
-            entry.setPitch(pitch);
+            entry.setPitch(pitch.get());
-            entry.setYaw(yaw);
+            entry.setYaw(yaw.get());
         }
 
         return !isDead();
@@ -154,7 +157,7 @@ public class PortalSpell extends AbstractSpell implements PlacementControlSpell.
             source.findAllEntitiesInRange(1).forEach(entity -> {
                 if (!entity.hasPortalCooldown()) {
 
-                    float approachYaw = Math.abs(MathHelper.wrapDegrees(entity.getYaw() - this.yaw));
+                    float approachYaw = Math.abs(MathHelper.wrapDegrees(entity.getYaw() - this.yaw.get()));
                     if (approachYaw > 80) {
                         return;
                     }
@@ -177,7 +180,6 @@ public class PortalSpell extends AbstractSpell implements PlacementControlSpell.
                     entity.getWorld().playSoundFromEntity(null, entity, USounds.ENTITY_PLAYER_UNICORN_TELEPORT, entity.getSoundCategory(), 1, 1);
                     entity.teleport((ServerWorld)entity.getWorld(), dest.x, dest.y, dest.z, PositionFlag.VALUES, yaw, entity.getPitch());
                     entity.getWorld().playSoundFromEntity(null, entity, USounds.ENTITY_PLAYER_UNICORN_TELEPORT, entity.getSoundCategory(), 1, 1);
-                    setDirty();
 
                     Living.updateVelocity(entity);
 
@@ -193,13 +195,12 @@ public class PortalSpell extends AbstractSpell implements PlacementControlSpell.
 
     @Override
     public void setOrientation(Caster<?> caster, float pitch, float yaw) {
-        this.pitch = 90 - pitch;
+        this.pitch.set(90 - pitch);
-        this.yaw = -yaw;
+        this.yaw.set(-yaw);
         particleArea = PARTICLE_AREA.rotate(
-            this.pitch * MathHelper.RADIANS_PER_DEGREE,
+            this.pitch.get() * MathHelper.RADIANS_PER_DEGREE,
-            this.yaw * MathHelper.RADIANS_PER_DEGREE
+            (180 - this.yaw.get()) * MathHelper.RADIANS_PER_DEGREE
         );
-        setDirty();
     }
 
     @Override
@@ -227,30 +228,26 @@ public class PortalSpell extends AbstractSpell implements PlacementControlSpell.
     @Override
     public void toNBT(NbtCompound compound) {
         super.toNBT(compound);
-        if (targetPortalId != null) {
+        compound.putUuid("targetPortalId", targetPortalId.get());
-            compound.putUuid("targetPortalId", targetPortalId);
-        }
-        compound.putBoolean("publishedPosition", publishedPosition);
         compound.put("teleportationTarget", teleportationTarget.toNBT());
-        compound.putFloat("pitch", pitch);
+        compound.putFloat("pitch", getPitch());
-        compound.putFloat("yaw", yaw);
+        compound.putFloat("yaw", getYaw());
-        compound.putFloat("targetPortalPitch", targetPortalPitch);
+        compound.putFloat("targetPortalPitch", getTargetPitch());
-        compound.putFloat("targetPortalYaw", targetPortalYaw);
+        compound.putFloat("targetPortalYaw", getTargetYaw());
     }
 
     @Override
     public void fromNBT(NbtCompound compound) {
         super.fromNBT(compound);
-        targetPortalId = compound.containsUuid("targetPortalId") ? compound.getUuid("targetPortalId") : null;
+        targetPortalId.set(compound.containsUuid("targetPortalId") ? compound.getUuid("targetPortalId") : Util.NIL_UUID);
-        publishedPosition = compound.getBoolean("publishedPosition");
         teleportationTarget.fromNBT(compound.getCompound("teleportationTarget"));
-        pitch = compound.getFloat("pitch");
+        pitch.set(compound.getFloat("pitch"));
-        yaw = compound.getFloat("yaw");
+        yaw.set(compound.getFloat("yaw"));
-        targetPortalPitch = compound.getFloat("targetPortalPitch");
+        targetPortalPitch.set(compound.getFloat("targetPortalPitch"));
-        targetPortalYaw = compound.getFloat("targetPortalYaw");
+        targetPortalYaw.set(compound.getFloat("targetPortalYaw"));
         particleArea = PARTICLE_AREA.rotate(
-            pitch * MathHelper.RADIANS_PER_DEGREE,
+            pitch.get() * MathHelper.RADIANS_PER_DEGREE,
-            (180 - yaw) * MathHelper.RADIANS_PER_DEGREE
+            (180 - yaw.get()) * MathHelper.RADIANS_PER_DEGREE
         );
     }
 }

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

@@ -16,6 +16,8 @@ import com.minelittlepony.unicopia.ability.magic.spell.SpellAttributes;
 import com.minelittlepony.unicopia.ability.magic.spell.trait.Trait;
 import com.minelittlepony.unicopia.entity.damage.UDamageTypes;
 import com.minelittlepony.unicopia.entity.player.Pony;
+import com.minelittlepony.unicopia.network.track.DataTracker;
+import com.minelittlepony.unicopia.network.track.TrackableDataType;
 import com.minelittlepony.unicopia.particle.FollowingParticleEffect;
 import com.minelittlepony.unicopia.particle.ParticleUtils;
 import com.minelittlepony.unicopia.particle.UParticles;
@@ -43,6 +45,7 @@ public class SiphoningSpell extends AbstractAreaEffectSpell {
         tooltip.add(SpellAttributes.of(SpellAttributes.RANGE, 4));
     }
 
+    private final DataTracker.Entry<Boolean> upset = dataTracker.startTracking(TrackableDataType.BOOLEAN, false);
     private int ticksUpset;
 
     protected SiphoningSpell(CustomisedSpellType<?> type) {
@@ -57,8 +60,8 @@ public class SiphoningSpell extends AbstractAreaEffectSpell {
     @Override
     public boolean tick(Caster<?> source, Situation situation) {
 
-        if (ticksUpset > 0) {
+        if (ticksUpset > 0 && --ticksUpset <= 0) {
-            ticksUpset--;
+            upset.set(false);
         }
 
         if (source.isClient()) {
@@ -108,7 +111,7 @@ public class SiphoningSpell extends AbstractAreaEffectSpell {
                 } else {
                     e.damage(damage, e.getHealth() / 4);
                     ticksUpset = 100;
-                    setDirty();
+                    upset.set(true);
                 }
             } else {
                 e.heal((float)Math.min(source.getLevel().getScaled(e.getHealth()) / 2F, maxHealthGain * 0.6));
@@ -174,5 +177,8 @@ public class SiphoningSpell extends AbstractAreaEffectSpell {
     public void fromNBT(NbtCompound compound) {
         super.fromNBT(compound);
         ticksUpset = compound.getInt("upset");
+        if (ticksUpset > 0) {
+            upset.set(true);
+        }
     }
 }

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

@@ -45,7 +45,7 @@ public final class SpellType<T extends Spell> implements Affine, SpellPredicate<
     private static final DynamicCommandExceptionType UNKNOWN_SPELL_TYPE_EXCEPTION = new DynamicCommandExceptionType(id -> Text.translatable("spell_type.unknown", id));
 
     public static final SpellType<PlacementControlSpell> PLACE_CONTROL_SPELL = register("place_controller", SpellType.<PlacementControlSpell>builder(PlacementControlSpell::new).affinity(Affinity.NEUTRAL).unobtainable().stackable().shape(GemstoneItem.Shape.DONUT));
-    public static final SpellType<ThrowableSpell> THROWN_SPELL = register("thrown", builder(ThrowableSpell::new).affinity(Affinity.NEUTRAL).unobtainable().shape(GemstoneItem.Shape.DONUT));
+    public static final SpellType<ThrowableSpell> THROWN_SPELL = register("thrown", SpellType.<ThrowableSpell>builder(ThrowableSpell::new).affinity(Affinity.NEUTRAL).unobtainable().shape(GemstoneItem.Shape.DONUT));
 
     public static final SpellType<DispersableDisguiseSpell> CHANGELING_DISGUISE = register("disguise", builder(DispersableDisguiseSpell::new).affinity(Affinity.BAD).color(0x19E48E).unobtainable().shape(GemstoneItem.Shape.ARROW));
     public static final SpellType<ChangelingFeedingSpell> FEED = register("feed", SpellType.<ChangelingFeedingSpell>builder(ChangelingFeedingSpell::new).affinity(Affinity.BAD).color(0xBDBDF9).unobtainable().shape(GemstoneItem.Shape.ARROW));

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

@@ -30,7 +30,7 @@ import net.minecraft.world.World;
  *
  * @param <T> The type of the entity this reference points to.
  */
-public class EntityReference<T extends Entity> implements NbtSerialisable, TrackableObject {
+public class EntityReference<T extends Entity> implements NbtSerialisable, TrackableObject<EntityReference<T>> {
     private static final Serializer<?> SERIALIZER = Serializer.of(EntityReference::new);
 
     @SuppressWarnings("unchecked")
@@ -122,12 +122,7 @@ public class EntityReference<T extends Entity> implements NbtSerialisable, Track
 
     @Override
     public int hashCode() {
-        return getUuid().hashCode();
+        return getTarget().map(EntityValues::uuid).orElse(Util.NIL_UUID).hashCode();
-    }
-
-    @Override
-    public UUID getUuid() {
-        return getTarget().map(EntityValues::uuid).orElse(Util.NIL_UUID);
     }
 
     @Override
@@ -140,7 +135,7 @@ public class EntityReference<T extends Entity> implements NbtSerialisable, Track
     }
 
     @Override
-    public NbtCompound toTrackedNbt() {
+    public NbtCompound writeTrackedNbt() {
         return toNBT();
     }
 
@@ -149,6 +144,12 @@ public class EntityReference<T extends Entity> implements NbtSerialisable, Track
         fromNBT(compound);
     }
 
+    @Override
+    public void copyTo(EntityReference<T> destination) {
+        destination.reference = reference;
+        destination.directReference = directReference;
+    }
+
     @Override
     public void discard(boolean immediate) {
         set(null);

src/main/java/com/minelittlepony/unicopia/entity/player/CorruptionHandler.java

@@ -38,12 +38,10 @@ public class CorruptionHandler implements Tickable {
             if (entity.age % (10 * ItemTracker.SECONDS) == 0) {
                 if (random.nextInt(100) == 0) {
                     pony.getCorruption().add(-1);
-                    pony.setDirty();
                 }
 
                 if (entity.getHealth() >= entity.getMaxHealth() - 1 && !entity.getHungerManager().isNotFull()) {
                     pony.getCorruption().add(-random.nextInt(4));
-                    pony.setDirty();
                 }
             }
         }
@@ -79,6 +77,5 @@ public class CorruptionHandler implements Tickable {
         MagicReserves reserves = pony.getMagicalReserves();
         reserves.getExertion().addPercent(10);
         reserves.getEnergy().add(10);
-        pony.setDirty();
     }
 }

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

@@ -1,37 +1,33 @@
 package com.minelittlepony.unicopia.network.track;
 
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
 
-import it.unimi.dsi.fastutil.ints.Int2ObjectMap;
-import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
 import it.unimi.dsi.fastutil.ints.IntOpenHashSet;
 import it.unimi.dsi.fastutil.ints.IntSet;
 import it.unimi.dsi.fastutil.objects.ObjectArrayList;
-import net.minecraft.nbt.NbtCompound;
 import net.minecraft.network.PacketByteBuf;
 
 public class DataTracker {
     private final List<Pair<?>> codecs = new ObjectArrayList<>();
     private IntSet dirtyIndices = new IntOpenHashSet();
-    private Int2ObjectMap<TrackableObject> persistentObjects = new Int2ObjectOpenHashMap<>();
+    private List<TrackableObject<?>> persistentObjects = new ObjectArrayList<>();
 
-    private final DataTrackerManager manager;
     private boolean initial = true;
 
     final int id;
 
-    public DataTracker(DataTrackerManager manager, int id) {
+    public DataTracker(int id) {
-        this.manager = manager;
         this.id = id;
     }
 
-    public <T extends TrackableObject> Entry<NbtCompound> startTracking(T value) {
+    public <T extends TrackableObject<T>> T startTracking(T value) {
-        Entry<NbtCompound> entry = startTracking(TrackableDataType.COMPRESSED_NBT, value.toTrackedNbt());
+        persistentObjects.add(value);
-        persistentObjects.put(entry.id(), value);
+        return value;
-        return entry;
     }
 
     public <T> Entry<T> startTracking(TrackableDataType<T> type, T initialValue) {
@@ -50,10 +46,6 @@ public class DataTracker {
     }
 
     private <T> void set(Entry<T> entry, T value) {
-        if (manager.isClient) {
-            return;
-        }
-
         Pair<T> pair = getPair(entry);
         if (!Objects.equals(pair.value, value)) {
             synchronized (this) {
@@ -63,25 +55,14 @@ public class DataTracker {
         }
     }
 
-    @SuppressWarnings("unchecked")
+    @SuppressWarnings({ "unchecked", "rawtypes" })
-    private void updateTrackables() {
-        for (var entry : persistentObjects.int2ObjectEntrySet()) {
-            int key = entry.getIntKey();
-            TrackableObject.Status status = entry.getValue().getStatus();
-            if (status == TrackableObject.Status.NEW || status == TrackableObject.Status.UPDATED) {
-                ((Pair<Object>)codecs.get(key)).value = entry.getValue().toTrackedNbt();
-                dirtyIndices.add(key);
-            }
-        }
-    }
-
-    @SuppressWarnings("unchecked")
     synchronized void copyTo(DataTracker destination) {
         for (int i = 0; i < codecs.size(); i++) {
             ((Pair<Object>)destination.codecs.get(i)).value = codecs.get(i).value;
-            TrackableObject o = destination.persistentObjects.get(i);
+            TrackableObject<?> a = persistentObjects.get(i);
-            if (o != null) {
+            TrackableObject<?> b = destination.persistentObjects.get(i);
-                o.readTrackedNbt((NbtCompound)codecs.get(i).value);
+            if (a != null && b != null) {
+                ((TrackableObject)a).copyTo(b);
             }
         }
     }
@@ -89,18 +70,17 @@ public class DataTracker {
     synchronized Optional<MsgTrackedValues.TrackerEntries> getInitialPairs() {
         initial = false;
         dirtyIndices = new IntOpenHashSet();
-        updateTrackables();
+        return Optional.of(new MsgTrackedValues.TrackerEntries(id, true, codecs, writePersistentObjects(true)));
-        return Optional.of(new MsgTrackedValues.TrackerEntries(id, true, codecs));
     }
 
-    synchronized Optional<MsgTrackedValues.TrackerEntries> getDirtyPairs() {
+    public synchronized Optional<MsgTrackedValues.TrackerEntries> getDirtyPairs() {
         if (initial) {
             return getInitialPairs();
         }
 
-        updateTrackables();
+        Map<Integer, PacketByteBuf> updates = writePersistentObjects(false);
 
-        if (dirtyIndices.isEmpty()) {
+        if (dirtyIndices.isEmpty() && updates.isEmpty()) {
             return Optional.empty();
         }
 
@@ -110,32 +90,40 @@ public class DataTracker {
         for (int i : toSend) {
             pairs.add(codecs.get(i));
         }
-        return Optional.of(new MsgTrackedValues.TrackerEntries(id, false, pairs));
+        return Optional.of(new MsgTrackedValues.TrackerEntries(id, false, pairs, updates));
     }
 
-    synchronized void load(MsgTrackedValues.TrackerEntries values) {
+    private Map<Integer, PacketByteBuf> writePersistentObjects(boolean initial) {
+        Map<Integer, PacketByteBuf> updates = new HashMap<>();
+        for (int i = 0; i < persistentObjects.size(); i++) {
+            TrackableObject<?> o = persistentObjects.get(i);
+            TrackableObject.Status status = initial ? TrackableObject.Status.NEW : o.getStatus();
+            int id = i;
+            o.write(status).ifPresent(data -> updates.put(id, data));
+        }
+        return updates;
+    }
+
+    public synchronized void load(MsgTrackedValues.TrackerEntries values) {
         if (values.wipe()) {
             codecs.clear();
             codecs.addAll(values.values());
-            for (var entry : persistentObjects.int2ObjectEntrySet()) {
-                Pair<?> pair = codecs.get(entry.getIntKey());
-                if (pair != null) {
-                    entry.getValue().readTrackedNbt((NbtCompound)pair.value);
-                }
-            }
         } else {
             for (var value : values.values()) {
                 if (value.id >= 0 && value.id < codecs.size()) {
                     if (codecs.get(value.id).type == value.type) {
                         codecs.set(value.id, value);
-                        TrackableObject o = persistentObjects.get(value.id);
-                        if (o != null) {
-                            o.readTrackedNbt((NbtCompound)value.value);
-                        }
                     }
                 }
             }
         }
+
+        for (var entry : values.objects().entrySet()) {
+            TrackableObject<?> o = persistentObjects.get(entry.getKey());
+            if (o != null) {
+                o.read(entry.getValue());
+            }
+        }
     }
 
     public record Entry<T>(DataTracker tracker, int id) {

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

@@ -41,7 +41,7 @@ public class DataTrackerManager {
     }
 
     public synchronized DataTracker checkoutTracker() {
-        DataTracker tracker = new DataTracker(this, trackers.size());
+        DataTracker tracker = new DataTracker(trackers.size());
         trackers.add(tracker);
         packetEmitters.add((sender, initial) -> {
             var update = initial ? tracker.getInitialPairs() : tracker.getDirtyPairs();
@@ -56,7 +56,7 @@ public class DataTrackerManager {
         return tracker;
     }
 
-    public synchronized <T extends TrackableObject> ObjectTracker<T> checkoutTracker(Supplier<T> objFunction) {
+    public synchronized <T extends TrackableObject<T>> ObjectTracker<T> checkoutTracker(Supplier<T> objFunction) {
         ObjectTracker<T> tracker = new ObjectTracker<>(objectTrackers.size(), objFunction);
         objectTrackers.add(tracker);
         packetEmitters.add((sender, initial) -> {

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

@@ -14,7 +14,6 @@ import com.sollace.fabwork.api.packets.HandledPacket;
 
 import net.minecraft.entity.Entity;
 import net.minecraft.entity.player.PlayerEntity;
-import net.minecraft.nbt.NbtCompound;
 import net.minecraft.network.PacketByteBuf;
 
 public record MsgTrackedValues(
@@ -45,12 +44,12 @@ public record MsgTrackedValues(
         }
     }
 
-    public record TrackerObjects(int id, Set<UUID> removedValues, Map<UUID, NbtCompound> values) {
+    public record TrackerObjects(int id, Set<UUID> removedValues, Map<UUID, PacketByteBuf> values) {
         public TrackerObjects(PacketByteBuf buffer) {
             this(
                 buffer.readInt(),
                 buffer.readCollection(HashSet::new, PacketByteBuf::readUuid),
-                buffer.readMap(HashMap::new, PacketByteBuf::readUuid, PacketCodec.COMPRESSED_NBT::read)
+                buffer.readMap(HashMap::new, PacketByteBuf::readUuid, PacketCodec.RAW_BYTES::read)
             );
 
         }
@@ -58,19 +57,25 @@ public record MsgTrackedValues(
         public void write(PacketByteBuf buffer) {
             buffer.writeInt(id);
             buffer.writeCollection(removedValues, PacketByteBuf::writeUuid);
-            buffer.writeMap(values, PacketByteBuf::writeUuid, PacketCodec.COMPRESSED_NBT::write);
+            buffer.writeMap(values, PacketByteBuf::writeUuid, PacketCodec.RAW_BYTES::write);
         }
     }
 
-    public record TrackerEntries(int id, boolean wipe, List<DataTracker.Pair<?>> values) {
+    public record TrackerEntries(int id, boolean wipe, List<DataTracker.Pair<?>> values, Map<Integer, PacketByteBuf> objects) {
         public TrackerEntries(PacketByteBuf buffer) {
-            this(buffer.readInt(), buffer.readBoolean(), buffer.readCollection(ArrayList::new, DataTracker.Pair::new));
+            this(
+                buffer.readInt(),
+                buffer.readBoolean(),
+                buffer.readCollection(ArrayList::new, DataTracker.Pair::new),
+                buffer.readMap(PacketByteBuf::readInt, PacketCodec.RAW_BYTES::read)
+            );
         }
 
         public void write(PacketByteBuf buffer) {
             buffer.writeInt(id);
             buffer.writeBoolean(wipe);
             buffer.writeCollection(values, (buf, pair) -> pair.write(buf));
+            buffer.writeMap(objects, PacketByteBuf::writeInt, PacketCodec.RAW_BYTES::write);
         }
     }
 }

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

@@ -11,14 +11,11 @@ import java.util.function.Supplier;
 
 import org.jetbrains.annotations.Nullable;
 
-import com.minelittlepony.unicopia.Unicopia;
+import com.minelittlepony.unicopia.network.track.TrackableObject.Status;
-import com.minelittlepony.unicopia.util.NbtSerialisable;
-
 import it.unimi.dsi.fastutil.objects.Object2ObjectOpenHashMap;
-import net.minecraft.nbt.NbtCompound;
+import net.minecraft.network.PacketByteBuf;
-import net.minecraft.util.Util;
 
-public class ObjectTracker<T extends TrackableObject> implements NbtSerialisable {
+public class ObjectTracker<T extends TrackableObject<T>> {
     private final Map<UUID, T> trackedObjects = new Object2ObjectOpenHashMap<>();
     private volatile Map<UUID, T> quickAccess = Map.of();
 
@@ -30,6 +27,10 @@ public class ObjectTracker<T extends TrackableObject> implements NbtSerialisable
         this.constructor = constructor;
     }
 
+    public Map<UUID, T> entries() {
+        return quickAccess;
+    }
+
     public Set<UUID> keySet() {
         return quickAccess.keySet();
     }
@@ -68,15 +69,15 @@ public class ObjectTracker<T extends TrackableObject> implements NbtSerialisable
         return true;
     }
 
-    public synchronized void add(T obj) {
+    public synchronized void add(UUID id, T obj) {
-        trackedObjects.put(obj.getUuid(), obj);
+        trackedObjects.put(id, obj);
         quickAccess = Map.copyOf(trackedObjects);
     }
 
     synchronized void copyTo(ObjectTracker<T> destination) {
         for (var entry : trackedObjects.entrySet()) {
             T copy = destination.constructor.get();
-            copy.readTrackedNbt(entry.getValue().toTrackedNbt());
+            entry.getValue().copyTo(copy);
             destination.trackedObjects.put(entry.getKey(), copy);
         }
         destination.quickAccess = Map.copyOf(destination.trackedObjects);
@@ -87,31 +88,35 @@ public class ObjectTracker<T extends TrackableObject> implements NbtSerialisable
             return Optional.empty();
         }
 
-        Map<UUID, NbtCompound> trackableCompounds = new HashMap<>();
+        Map<UUID, PacketByteBuf> updates = new HashMap<>();
         quickAccess.entrySet().forEach(object -> {
-            trackableCompounds.put(object.getKey(), object.getValue().toTrackedNbt());
+            object.getValue().write(Status.NEW).ifPresent(data -> {
+                updates.put(object.getKey(), data);
+            });
         });
 
-        return Optional.of(new MsgTrackedValues.TrackerObjects(id, Set.of(), trackableCompounds));
+        return Optional.of(new MsgTrackedValues.TrackerObjects(id, Set.of(), updates));
     }
 
     synchronized Optional<MsgTrackedValues.TrackerObjects> getDirtyPairs() {
         if (!trackedObjects.isEmpty()) {
-            Map<UUID, NbtCompound> trackableCompounds = new HashMap<>();
+            Map<UUID, PacketByteBuf> updates = new HashMap<>();
             Set<UUID> removedTrackableObjects = new HashSet<>();
             trackedObjects.entrySet().removeIf(object -> {
                 TrackableObject.Status status = object.getValue().getStatus();
                 if (status == TrackableObject.Status.REMOVED) {
                     removedTrackableObjects.add(object.getKey());
-                } else if (status != TrackableObject.Status.DEFAULT) {
+                    return true;
-                    trackableCompounds.put(object.getKey(), object.getValue().toTrackedNbt());
                 }
-                return status == TrackableObject.Status.REMOVED;
+                object.getValue().write(status).ifPresent(data -> {
+                    updates.put(object.getKey(), data);
+                });
+                return false;
             });
             quickAccess = Map.copyOf(trackedObjects);
 
-            if (!trackableCompounds.isEmpty() || !removedTrackableObjects.isEmpty()) {
+            if (!updates.isEmpty() || !removedTrackableObjects.isEmpty()) {
-                return Optional.of(new MsgTrackedValues.TrackerObjects(id, removedTrackableObjects, trackableCompounds));
+                return Optional.of(new MsgTrackedValues.TrackerObjects(id, removedTrackableObjects, updates));
             }
         }
 
@@ -125,44 +130,18 @@ public class ObjectTracker<T extends TrackableObject> implements NbtSerialisable
                 o.discard(true);
             }
         });
-        objects.values().forEach((id, nbt) -> {
+        objects.values().forEach((id, data) -> {
             T o = trackedObjects.get(id);
             if (o == null) {
                 o = constructor.get();
                 trackedObjects.put(id, o);
             }
-            o.readTrackedNbt(nbt);
+            o.read(data);
         });
         quickAccess = Map.copyOf(trackedObjects);
     }
 
-    @Override
+    public void load(Map<UUID, T> values) {
-    public synchronized void toNBT(NbtCompound compound) {
-        quickAccess.forEach((id, value) -> {
-            compound.put(id.toString(), value.toTrackedNbt());
-        });
-    }
-
-    @Override
-    public void fromNBT(NbtCompound compound) {
-        Map<UUID, T> values = new Object2ObjectOpenHashMap<>();
-        compound.getKeys().forEach(key -> {
-            try {
-                UUID id = Util.NIL_UUID;
-                try {
-                    id = UUID.fromString(key);
-                } catch (Throwable ignore) {}
-
-                if (id != null && !Util.NIL_UUID.equals(id)) {
-                    NbtCompound nbt = compound.getCompound(key);
-                    T entry = constructor.get();
-                    entry.readTrackedNbt(nbt);
-                    values.put(id, entry);
-                }
-            } catch (Throwable t) {
-                Unicopia.LOGGER.warn("Exception loading tracked object: {}", t.getMessage());
-            }
-        });
         synchronized (this) {
             trackedObjects.clear();
             trackedObjects.putAll(values);

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

@@ -23,6 +23,7 @@ public record TrackableDataType<T>(int id, PacketCodec<T> codec) {
     public static final TrackableDataType<UUID> UUID = of(new Identifier("uuid"), PacketCodec.UUID);
     public static final TrackableDataType<NbtCompound> NBT = of(new Identifier("nbt"), PacketCodec.NBT);
     public static final TrackableDataType<NbtCompound> COMPRESSED_NBT = of(new Identifier("compressed_nbt"), PacketCodec.COMPRESSED_NBT);
+    public static final TrackableDataType<Optional<PacketByteBuf>> RAW_BYTES = of(new Identifier("raw_bytes"), PacketCodec.RAW_BYTES.asOptional());
 
     public static final TrackableDataType<Optional<BlockPos>> OPTIONAL_POS = of(new Identifier("optional_pos"), PacketCodec.OPTIONAL_POS);
     public static final TrackableDataType<Race> RACE = TrackableDataType.of(Unicopia.id("race"), PacketCodec.ofRegistry(Race.REGISTRY));

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

@@ -1,20 +1,37 @@
 package com.minelittlepony.unicopia.network.track;
 
-import java.util.UUID;
+import java.util.Optional;
 
+import com.minelittlepony.unicopia.util.serialization.PacketCodec;
+
+import io.netty.buffer.Unpooled;
 import net.minecraft.nbt.NbtCompound;
+import net.minecraft.network.PacketByteBuf;
 
-public interface TrackableObject {
+public interface TrackableObject<T extends TrackableObject<T>> {
-    UUID getUuid();
-
     Status getStatus();
 
-    NbtCompound toTrackedNbt();
+    default void read(PacketByteBuf buffer) {
+        readTrackedNbt(PacketCodec.COMPRESSED_NBT.read(buffer));
+    }
 
-    void readTrackedNbt(NbtCompound compound);
+    default Optional<PacketByteBuf> write(Status status) {
+        if (status == Status.NEW || status == Status.UPDATED) {
+            PacketByteBuf buffer = new PacketByteBuf(Unpooled.buffer());
+            PacketCodec.COMPRESSED_NBT.write(buffer, writeTrackedNbt());
+            return Optional.of(buffer);
+        }
+        return Optional.empty();
+    }
+
+    void readTrackedNbt(NbtCompound nbt);
+
+    NbtCompound writeTrackedNbt();
 
     void discard(boolean immediate);
 
+    void copyTo(T destination);
+
     public enum Status {
         DEFAULT,
         NEW,

src/main/java/com/minelittlepony/unicopia/server/world/Ether.java

@@ -37,7 +37,7 @@ public class Ether extends PersistentState {
         this.world = world;
         this.endpoints = NbtSerialisable.readMap(compound.getCompound("endpoints"), Identifier::tryParse, typeNbt -> {
             return NbtSerialisable.readMap((NbtCompound)typeNbt, UUID::fromString, entityNbt -> {
-                return NbtSerialisable.readMap((NbtCompound)entityNbt, UUID::fromString, Entry::new);
+                return NbtSerialisable.readMap((NbtCompound)entityNbt, UUID::fromString, nbt -> new Entry<>(nbt));
             });
         });
     }

src/main/java/com/minelittlepony/unicopia/util/NbtSerialisable.java

@@ -69,14 +69,31 @@ public interface NbtSerialisable {
     }
 
     static <K, V> Map<K, V> readMap(NbtCompound nbt, Function<String, K> keyFunction, Function<NbtElement, V> valueFunction) {
-        return nbt.getKeys().stream().collect(Collectors.toMap(keyFunction, k -> valueFunction.apply(nbt.get(k))));
+        return readMap(nbt, keyFunction, (k, v) -> valueFunction.apply(v));
+    }
+
+    static <K, V> Map<K, V> readMap(NbtCompound nbt, Function<String, K> keyFunction, BiFunction<K, NbtElement, V> valueFunction) {
+        return nbt.getKeys().stream().map(k -> {
+            K key = keyFunction.apply(k);
+            if (key == null) {
+                return null;
+            }
+            V value = valueFunction.apply(key, nbt.get(k));
+            if (value == null) {
+                return null;
+            }
+            return Map.entry(key, value);
+        })
+        .filter(Objects::nonNull)
+        .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
     }
 
     static <K, V> NbtCompound writeMap(Map<K, V> map, Function<K, String> keyFunction, Function<V, ? extends NbtElement> valueFunction) {
-        NbtCompound nbt = new NbtCompound();
+        return writeMap(new NbtCompound(), map, keyFunction, valueFunction);
-        map.forEach((k, v) -> {
+    }
-            nbt.put(keyFunction.apply(k), valueFunction.apply(v));
+
-        });
+    static <K, V> NbtCompound writeMap(NbtCompound nbt, Map<K, V> map, Function<K, String> keyFunction, Function<V, ? extends NbtElement> valueFunction) {
+        map.forEach((k, v) -> nbt.put(keyFunction.apply(k), valueFunction.apply(v)));
         return nbt;
     }