Replacing reflection to use a mixin for accessing the GoalSelector.

src/main/java/com/owlmaddie/goals/GoalUtils.java

 package com.owlmaddie.goals;
 
+import com.owlmaddie.mixin.MixinMobEntity;
 import net.minecraft.entity.ai.goal.GoalSelector;
 import net.minecraft.entity.mob.MobEntity;
 
-import java.lang.reflect.Field;
 
 /**
  * The {@code GoalUtils} class uses reflection to extend the MobEntity class
@@ -11,23 +11,8 @@ import java.lang.reflect.Field;
  */
 public class GoalUtils {
 
-    private static Field goalSelectorField;
-
-    static {
-        try {
-            goalSelectorField = MobEntity.class.getDeclaredField("goalSelector");
-            goalSelectorField.setAccessible(true);
-        } catch (NoSuchFieldException e) {
-            // Handle the exception, perhaps the field name has changed
-        }
-    }
-
     public static GoalSelector getGoalSelector(MobEntity mobEntity) {
-        try {
-            return (GoalSelector) goalSelectorField.get(mobEntity);
-        } catch (IllegalAccessException e) {
-            // Handle the exception
-            return null;
-        }
+        MixinMobEntity mixingEntity = (MixinMobEntity)mobEntity;
+        return mixingEntity.getGoalSelector();
     }
 }

src/main/java/com/owlmaddie/mixin/MixinMobEntity.java

+package com.owlmaddie.mixin;
+
+import org.spongepowered.asm.mixin.Mixin;
+import net.minecraft.entity.mob.MobEntity;
+import org.spongepowered.asm.mixin.gen.Accessor;
+import net.minecraft.entity.ai.goal.GoalSelector;
+
+/**
+ * The {@code MixinMobEntity} mixin class exposes the goalSelector field from the MobEntity class.
+ */
+@Mixin(MobEntity.class)
+public interface MixinMobEntity {
+    @Accessor("goalSelector") public GoalSelector getGoalSelector();
+}
\ No newline at end of file

src/main/resources/mobgpt.mixins.json

@@ -3,7 +3,8 @@
 	"package": "com.owlmaddie.mixin",
 	"compatibilityLevel": "JAVA_17",
 	"mixins": [
-		"ExampleMixin"
+		"ExampleMixin",
+		"MixinMobEntity"
 	],
 	"injectors": {
 		"defaultRequire": 1