Fix issues disguising as crystal shards and prevent disguises from dropping items

src/main/java/com/minelittlepony/unicopia/entity/behaviour/Guest.java

@@ -2,8 +2,14 @@ package com.minelittlepony.unicopia.entity.behaviour;
 
 import com.minelittlepony.unicopia.ability.magic.Caster;
 
+import net.minecraft.entity.Entity;
+
 public interface Guest {
     void setHost(Caster<?> host);
 
     Caster<?> getHost();
+
+    static boolean hasHost(Entity entity) {
+        return ((Guest)entity).getHost() != null;
+    }
 }

src/main/java/com/minelittlepony/unicopia/entity/duck/EntityDuck.java

@@ -3,13 +3,14 @@ package com.minelittlepony.unicopia.entity.duck;
 import java.util.Set;
 
 import com.minelittlepony.unicopia.compat.pehkui.PehkuiEntityExtensions;
+import com.minelittlepony.unicopia.entity.behaviour.Guest;
 
 import net.minecraft.entity.Entity;
 import net.minecraft.entity.Entity.RemovalReason;
 import net.minecraft.fluid.Fluid;
 import net.minecraft.registry.tag.TagKey;
 
-public interface EntityDuck extends LavaAffine, PehkuiEntityExtensions {
+public interface EntityDuck extends LavaAffine, PehkuiEntityExtensions, Guest {
 
     Set<TagKey<Fluid>> getSubmergedFluidTags();
 

src/main/java/com/minelittlepony/unicopia/entity/duck/LivingEntityDuck.java

@@ -1,13 +1,11 @@
 package com.minelittlepony.unicopia.entity.duck;
 
-import com.minelittlepony.unicopia.entity.behaviour.Guest;
-
 import net.minecraft.entity.LivingEntity;
 import net.minecraft.item.ItemStack;
 import net.minecraft.util.Hand;
 import net.minecraft.util.math.Vec3d;
 
-public interface LivingEntityDuck extends Guest {
+public interface LivingEntityDuck extends EntityDuck {
     void updateItemUsage(Hand hand, ItemStack stack, int time);
 
     boolean isJumping();

src/main/java/com/minelittlepony/unicopia/entity/mob/CrystalShardsEntity.java

@@ -8,6 +8,7 @@ import java.util.stream.Collectors;
 import org.jetbrains.annotations.Nullable;
 
 import com.minelittlepony.unicopia.USounds;
+import com.minelittlepony.unicopia.entity.behaviour.Guest;
 import com.minelittlepony.unicopia.item.UItems;
 import com.minelittlepony.unicopia.particle.ParticleUtils;
 
@@ -172,9 +173,11 @@ public class CrystalShardsEntity extends StationaryObjectEntity {
             }
         }
 
-        if (isDead() || isInvalid(getWorld(), getBlockPos(), getAttachmentFace())) {
-            kill();
-            ParticleUtils.spawnParticles(ParticleTypes.CLOUD, this, 10);
+        if (!Guest.hasHost(this)) {
+            if (isDead() || isInvalid(getWorld(), getBlockPos(), getAttachmentFace())) {
+                kill();
+                ParticleUtils.spawnParticles(ParticleTypes.CLOUD, this, 10);
+            }
         }
     }
 

src/main/java/com/minelittlepony/unicopia/entity/mob/StationaryObjectEntity.java

@@ -59,7 +59,6 @@ public abstract class StationaryObjectEntity extends Entity implements UDamageSo
     }
 
     protected void onHurt() {
-
     }
 
     @Override

src/main/java/com/minelittlepony/unicopia/mixin/MixinEntity.java

@@ -2,6 +2,7 @@ package com.minelittlepony.unicopia.mixin;
 
 import java.util.Set;
 
+import org.jetbrains.annotations.Nullable;
 import org.spongepowered.asm.mixin.Mixin;
 import org.spongepowered.asm.mixin.gen.Accessor;
 import org.spongepowered.asm.mixin.injection.At;
@@ -12,18 +13,35 @@ import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
 import com.minelittlepony.unicopia.entity.duck.LavaAffine;
 import com.minelittlepony.unicopia.EquinePredicates;
 import com.minelittlepony.unicopia.Race;
+import com.minelittlepony.unicopia.ability.magic.Caster;
 import com.minelittlepony.unicopia.entity.Equine;
 import com.minelittlepony.unicopia.entity.Living;
 import com.minelittlepony.unicopia.entity.duck.EntityDuck;
 
 import net.minecraft.entity.Entity;
+import net.minecraft.entity.ItemEntity;
 import net.minecraft.entity.Entity.PositionUpdater;
 import net.minecraft.entity.Entity.RemovalReason;
 import net.minecraft.fluid.Fluid;
+import net.minecraft.item.ItemStack;
 import net.minecraft.registry.tag.TagKey;
 
 @Mixin(Entity.class)
 abstract class MixinEntity implements EntityDuck {
+    @Nullable
+    private transient Caster<?> host;
+
+    @Override
+    @Nullable
+    public Caster<?> getHost() {
+        return host;
+    }
+
+    @Override
+    public void setHost(Caster<?> host) {
+        this.host = host;
+    }
+
     @Override
     @Accessor("submergedFluidTag")
     public abstract Set<TagKey<Fluid>> getSubmergedFluidTags();
@@ -83,4 +101,11 @@ abstract class MixinEntity implements EntityDuck {
             info.cancel();
         }
     }
+
+    @Inject(method = "dropStack(Lnet/minecraft/item/ItemStack;F)Lnet/minecraft/entity/ItemEntity;", at = @At("HEAD"), cancellable = true)
+    private void onDropStack(ItemStack stack, float yOffset, CallbackInfoReturnable<ItemEntity> info) {
+        if (getHost() != null) {
+            info.setReturnValue(null);
+        }
+    }
 }

src/main/java/com/minelittlepony/unicopia/mixin/MixinLivingEntity.java

@@ -2,7 +2,6 @@ package com.minelittlepony.unicopia.mixin;
 
 import java.util.Optional;
 
-import org.jetbrains.annotations.Nullable;
 import org.spongepowered.asm.mixin.*;
 import org.spongepowered.asm.mixin.gen.Accessor;
 import org.spongepowered.asm.mixin.injection.At;
@@ -41,8 +40,6 @@ abstract class MixinLivingEntity extends Entity implements LivingEntityDuck, Equ
     private Optional<BlockPos> climbingPos;
 
     private Equine<?> caster;
-    @Nullable
-    private transient Caster<?> host;
 
     private MixinLivingEntity() { super(null, null); }
 
@@ -62,17 +59,6 @@ abstract class MixinLivingEntity extends Entity implements LivingEntityDuck, Equ
         return (Living<?>)caster;
     }
 
-    @Override
-    @Nullable
-    public Caster<?> getHost() {
-        return host;
-    }
-
-    @Override
-    public void setHost(Caster<?> host) {
-        this.host = host;
-    }
-
     @Override
     @Accessor("jumping")
     public abstract boolean isJumping();