Add and clarify Attribute#getDefaultValue (#13345)

Author: Warriorrrr

paper-api/src/main/java/org/bukkit/attribute/Attribute.java

@@ -10,6 +10,7 @@
 import org.bukkit.NamespacedKey;
 import org.bukkit.Registry;
 import org.bukkit.Translatable;
+import org.bukkit.entity.EntityType;
 import org.bukkit.util.OldEnum;
 import org.jetbrains.annotations.NotNull;
 
@@ -170,6 +171,13 @@ private static Attribute getAttribute(@NotNull @KeyPattern.Value String key) {
     @NotNull
     Sentiment getSentiment();
 
+    /**
+     * {@return the default value of this attribute}
+     * <p>
+     * Default attribute values may differ between entity types, use {@link EntityType#getDefaultAttributes()} to get default attribute values for a specific entity type.
+     */
+    double getDefaultValue();
+
     /**
      * @param name of the attribute.
      * @return the attribute with the given name.

paper-api/src/main/java/org/bukkit/attribute/AttributeInstance.java

@@ -111,6 +111,11 @@ public interface AttributeInstance {
      * Gets the default value of the Attribute attached to this instance.
      *
      * @return server default value
+     * @deprecated this method is placed misleadingly as it does not return the default value in the current entity's context, but in the server's context.
+     *  Use {@link Attribute#getDefaultValue()} as a replacement and see the note there about default values for specific entity types
+     * @see Attribute#getDefaultValue()
+     * @see org.bukkit.entity.EntityType#getDefaultAttributes()
      */
+    @Deprecated(since = "26.1")
     double getDefaultValue();
 }

paper-server/patches/sources/net/minecraft/world/entity/animal/equine/AbstractChestedHorse.java.patch

@@ -1,6 +1,6 @@
 --- a/net/minecraft/world/entity/animal/equine/AbstractChestedHorse.java
 +++ b/net/minecraft/world/entity/animal/equine/AbstractChestedHorse.java
-@@ -75,6 +_,16 @@
+@@ -74,6 +_,14 @@
          super.dropEquipment(level);
          if (this.hasChest()) {
              this.spawnAtLocation(level, Blocks.CHEST);

paper-server/src/main/java/org/bukkit/craftbukkit/attribute/CraftAttribute.java

@@ -53,6 +53,11 @@ public Sentiment getSentiment() {
         return Sentiment.valueOf(this.getHandle().sentiment.name());
     }
 
+    @Override
+    public double getDefaultValue() {
+        return this.getHandle().getDefaultValue();
+    }
+
     @Override
     public String getTranslationKey() {
         return this.getHandle().getDescriptionId();