Copper golems cause huge lag spikes when checking chests

Hey!

Could you please record a video of this issue?
Could you please also write do fps drop on specific place or specific action?

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Here is the requested video, this website refuses to let me upload it, so I had to use a google drive link.

https://drive.google.com/file/d/1LQjTUJCYCVx-fkt50uY-ZyNGb2SmCNV6/view?usp=sharing&t=5

As you can see, once the copper golems are all killed, the lag completely vanishes instantly.

here’s another video. the bug appears to happen when copper chests open near copper golems.

As of 1.21.9 Pre-Release 2, the issue still happens when the copper golems are checking chests. Copper golems will no longer cause lag when queuing for a chest other copper golems are checking, so my previous example will not cause much lag, but they still cause just as much lag when they are checking chests themselves. I’ll attach a new video with an example

I wrote a patch that seems to help with the remaining issue while the chests are open

Index: net/minecraft/world/entity/ai/behavior/TransportItemsBetweenContainers.java
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/net/minecraft/world/entity/ai/behavior/TransportItemsBetweenContainers.java b/net/minecraft/world/entity/ai/behavior/TransportItemsBetweenContainers.java
--- a/net/minecraft/world/entity/ai/behavior/TransportItemsBetweenContainers.java	(revision 9ceed0392b1bed23ac562ba56adc889d3d60315a)
+++ b/net/minecraft/world/entity/ai/behavior/TransportItemsBetweenContainers.java	(date 1758315147845)
@@ -62,6 +62,7 @@
     @Nullable
     private TransportItemsBetweenContainers.ContainerInteractionState interactionState;
     private int ticksSinceReachingTarget;
+    @Nullable private net.minecraft.world.level.pathfinder.Path interactionPath;
 
     public TransportItemsBetweenContainers(
         float speedModifier,
@@ -213,6 +214,7 @@
     }
 
     private void startOnReachedTargetInteraction(TransportItemsBetweenContainers.TransportItemTarget target, PathfinderMob mob) {
+        this.interactionPath = mob.getNavigation().getPath();
         this.doReachedTargetInteraction(
             mob,
             target.container,
@@ -225,6 +227,7 @@
     }
 
     private void onStartTravelling(PathfinderMob mob) {
+        this.interactionPath = null;
         this.onStartTravelling.accept(mob);
         this.setTransportingState(TransportItemsBetweenContainers.TransportItemState.TRAVELLING);
         this.interactionState = null;
@@ -333,7 +336,9 @@
                 return true;
             }
 
-            Path path = mob.getNavigation().getPath() == null ? mob.getNavigation().createPath(this.target.pos, 0) : mob.getNavigation().getPath();
+            Path path = mob.getNavigation().getPath();
+            if (path == null && this.state.equals(net.minecraft.world.entity.ai.behavior.TransportItemsBetweenContainers.TransportItemState.INTERACTING)) path = this.interactionPath;
+            if (path == null) path = mob.getNavigation().createPath(this.target.pos, 0);
             Vec3 positionToReachTargetFrom = this.getPositionToReachTargetFrom(path, mob);
             boolean isWithinTargetDistance = this.isWithinTargetDistance(getInteractionRange(mob), this.target, level, mob, positionToReachTargetFrom);
             boolean flag1 = path == null && !isWithinTargetDistance;