Fix attributes not being fully sent for the first player login

src/main/java/net/minestom/server/attribute/Attribute.java

@@ -13,6 +13,10 @@ public class Attribute {
 
     private static final Map<String, Attribute> ATTRIBUTES = new HashMap<>();
 
+    static {
+        Attributes.init();
+    }
+
     private final String key;
     private final float defaultValue;
     private final float maxValue;

src/main/java/net/minestom/server/attribute/AttributeInstance.java

@@ -24,6 +24,7 @@ public class AttributeInstance {
         this.attribute = attribute;
         this.propertyChangeListener = listener;
         this.baseValue = attribute.getDefaultValue();
+        refreshCachedValue();
     }
 
     /**
@@ -90,6 +91,7 @@ public class AttributeInstance {
      *
      * @return the modifiers.
      */
+    @NotNull
     public Collection<AttributeModifier> getModifiers() {
         return modifiers.values();
     }
@@ -107,18 +109,19 @@ public class AttributeInstance {
      * Recalculate the value of this attribute instance using the modifiers.
      */
     protected void refreshCachedValue() {
+        final Collection<AttributeModifier> modifiers = getModifiers();
         float base = getBaseValue();
 
-        for (var modifier : modifiers.values().stream().filter(mod -> mod.getOperation() == AttributeOperation.ADDITION).toArray(AttributeModifier[]::new)) {
+        for (var modifier : modifiers.stream().filter(mod -> mod.getOperation() == AttributeOperation.ADDITION).toArray(AttributeModifier[]::new)) {
             base += modifier.getAmount();
         }
 
         float result = base;
 
-        for (var modifier : modifiers.values().stream().filter(mod -> mod.getOperation() == AttributeOperation.MULTIPLY_BASE).toArray(AttributeModifier[]::new)) {
+        for (var modifier : modifiers.stream().filter(mod -> mod.getOperation() == AttributeOperation.MULTIPLY_BASE).toArray(AttributeModifier[]::new)) {
             result += (base * modifier.getAmount());
         }
-        for (var modifier : modifiers.values().stream().filter(mod -> mod.getOperation() == AttributeOperation.MULTIPLY_TOTAL).toArray(AttributeModifier[]::new)) {
+        for (var modifier : modifiers.stream().filter(mod -> mod.getOperation() == AttributeOperation.MULTIPLY_TOTAL).toArray(AttributeModifier[]::new)) {
             result *= (1.0f + modifier.getAmount());
         }
 

src/main/java/net/minestom/server/attribute/Attributes.java

@@ -4,6 +4,7 @@ package net.minestom.server.attribute;
  * The Minecraft, vanilla, standards attributes.
  */
 public final class Attributes {
+
     public static final Attribute MAX_HEALTH = (new Attribute("generic.max_health", true, 20, 1024)).register();
     public static final Attribute FOLLOW_RANGE = (new Attribute("generic.follow_range", true, 32, 2048)).register();
     public static final Attribute KNOCKBACK_RESISTANCE = (new Attribute("generic.knockback_resistance", true, 0, 1)).register();
@@ -21,4 +22,8 @@ public final class Attributes {
     private Attributes() throws IllegalAccessException {
         throw new IllegalAccessException("Cannot instantiate a static class");
     }
+
+    protected static void init() {
+        // Empty, here to register all the vanilla attributes
+    }
 }

src/main/java/net/minestom/server/entity/LivingEntity.java

@@ -31,11 +31,7 @@ import net.minestom.server.utils.validate.Check;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
-import java.util.ArrayList;
+import java.util.*;
-import java.util.Iterator;
-import java.util.List;
-import java.util.Map;
-import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.function.Consumer;
 
@@ -507,12 +503,15 @@ public abstract class LivingEntity extends Entity implements EquipmentHandler {
      */
     @NotNull
     protected EntityPropertiesPacket getPropertiesPacket() {
+        // Get all the attributes which should be sent to the client
+        final AttributeInstance[] instances = attributeModifiers.values().stream()
+                .filter(i -> i.getAttribute().isShared())
+                .toArray(AttributeInstance[]::new);
+
+
         EntityPropertiesPacket propertiesPacket = new EntityPropertiesPacket();
         propertiesPacket.entityId = getEntityId();
 
-        AttributeInstance[] instances = attributeModifiers.values().stream()
-                .filter(i -> i.getAttribute().isShared())
-                .toArray(AttributeInstance[]::new);
         EntityPropertiesPacket.Property[] properties = new EntityPropertiesPacket.Property[instances.length];
         for (int i = 0; i < properties.length; ++i) {
             EntityPropertiesPacket.Property property = new EntityPropertiesPacket.Property();
@@ -535,7 +534,8 @@ public abstract class LivingEntity extends Entity implements EquipmentHandler {
      */
     private void setupAttributes() {
         for (Attribute attribute : Attribute.values()) {
-            attributeModifiers.put(attribute.getKey(), new AttributeInstance(attribute, this::onAttributeChanged));
+            final AttributeInstance attributeInstance = new AttributeInstance(attribute, this::onAttributeChanged);
+            this.attributeModifiers.put(attribute.getKey(), attributeInstance);
         }
     }