Paper/patches/unapplied/server/0340-MC-145656-Fix-Follow-Range-Initial-Target.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: William Blake Galbreath <Blake.Galbreath@GMail.com>
Date: Wed, 18 Dec 2019 22:21:35 -0600
Subject: [PATCH] MC-145656 Fix Follow Range Initial Target


diff --git a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
index 68448d9ae6650beabcc62128772c6a18754788c4..297adb65c486abccd42cdb3b042e651a767c69cf 100644
--- a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
+++ b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
@@ -488,5 +488,10 @@ public class PaperWorldConfig {
     private void generatorSettings() {
         generateFlatBedrock = getBoolean("generator-settings.flat-bedrock", this.generateFlatBedrock);
     }
+
+    public boolean entitiesTargetWithFollowRange = false;
+    private void entitiesTargetWithFollowRange() {
+        entitiesTargetWithFollowRange = getBoolean("entities-target-with-follow-range", entitiesTargetWithFollowRange);
+    }
 }
 
diff --git a/src/main/java/net/minecraft/world/entity/ai/goal/target/NearestAttackableTargetGoal.java b/src/main/java/net/minecraft/world/entity/ai/goal/target/NearestAttackableTargetGoal.java
index 638942d54c6ea2d305350a330ac9fb8b82294f53..c6fc08d13b4cf3141ff31bed99294bdbace1c5e2 100644
--- a/src/main/java/net/minecraft/world/entity/ai/goal/target/NearestAttackableTargetGoal.java
+++ b/src/main/java/net/minecraft/world/entity/ai/goal/target/NearestAttackableTargetGoal.java
@@ -38,6 +38,7 @@ public class NearestAttackableTargetGoal<T extends LivingEntity> extends TargetG
         this.randomInterval = reducedTickDelay(reciprocalChance);
         this.setFlags(EnumSet.of(Goal.Flag.TARGET));
         this.targetConditions = TargetingConditions.forCombat().range(this.getFollowDistance()).selector(targetPredicate);
+        if (mob.level.paperConfig.entitiesTargetWithFollowRange) this.targetConditions.useFollowRange(); // Paper
     }
 
     @Override
diff --git a/src/main/java/net/minecraft/world/entity/ai/targeting/TargetingConditions.java b/src/main/java/net/minecraft/world/entity/ai/targeting/TargetingConditions.java
index 9f65f6cdbcc054bde03c42d7d3b16f65b93e5deb..a7575b5ef56af6f53448d391abb4956e130148ca 100644
--- a/src/main/java/net/minecraft/world/entity/ai/targeting/TargetingConditions.java
+++ b/src/main/java/net/minecraft/world/entity/ai/targeting/TargetingConditions.java
@@ -76,7 +76,7 @@ public class TargetingConditions {
 
                 if (this.range > 0.0D) {
                     double d = this.testInvisible ? targetEntity.getVisibilityPercent(baseEntity) : 1.0D;
-                    double e = Math.max(this.range * d, 2.0D);
+                    double e = Math.max((this.useFollowRange ? this.getFollowRange(baseEntity) : this.range) * d, 2.0D); // Paper
                     double f = baseEntity.distanceToSqr(targetEntity.getX(), targetEntity.getY(), targetEntity.getZ());
                     if (f > e * e) {
                         return false;
@@ -94,4 +94,18 @@ public class TargetingConditions {
             return true;
         }
     }
+
+    // Paper start
+    private boolean useFollowRange = false;
+
+    public TargetingConditions useFollowRange() {
+        this.useFollowRange = true;
+        return this;
+    }
+
+    private double getFollowRange(LivingEntity entityliving) {
+        net.minecraft.world.entity.ai.attributes.AttributeInstance attributeinstance = entityliving.getAttribute(net.minecraft.world.entity.ai.attributes.Attributes.FOLLOW_RANGE);
+        return attributeinstance == null ? 16.0D : attributeinstance.getValue();
+    }
+    // Paper end
 }