PaperMC/nms-patches/ItemDye.patch

--- a/net/minecraft/server/ItemDye.java
+++ b/net/minecraft/server/ItemDye.java
@@ -3,6 +3,8 @@
 import com.google.common.collect.Maps;
 import java.util.Map;
 
+import org.bukkit.event.entity.SheepDyeWoolEvent; // CraftBukkit
+
 public class ItemDye extends Item {
 
     private static final Map<EnumColor, ItemDye> a = Maps.newEnumMap(EnumColor.class);
@@ -21,7 +23,17 @@
 
             if (entitysheep.isAlive() && !entitysheep.isSheared() && entitysheep.getColor() != this.b) {
                 if (!entityhuman.world.isClientSide) {
-                    entitysheep.setColor(this.b);
+                    // CraftBukkit start
+                    byte bColor = (byte) this.b.getColorIndex();
+                    SheepDyeWoolEvent event = new SheepDyeWoolEvent((org.bukkit.entity.Sheep) entitysheep.getBukkitEntity(), org.bukkit.DyeColor.getByWoolData(bColor));
+                    entitysheep.world.getServer().getPluginManager().callEvent(event);
+
+                    if (event.isCancelled()) {
+                        return EnumInteractionResult.PASS;
+                    }
+
+                    entitysheep.setColor(EnumColor.fromColorIndex((byte) event.getColor().getWoolData()));
+                    // CraftBukkit end
                     itemstack.subtract(1);
                 }