Gale/patches/server/0143-Forget-radius-aware-dependency-node-parents.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Martijn Muijsers <martijnmuijsers@live.nl>
Date: Thu, 10 Aug 2023 21:04:04 +0200
Subject: [PATCH] Forget radius-aware dependency node parents

License: GPL-3.0 (https://www.gnu.org/licenses/gpl-3.0.html)
Gale - https://galemc.org

diff --git a/src/main/java/io/papermc/paper/chunk/system/scheduling/queue/RadiusAwarePrioritisedExecutor.java b/src/main/java/io/papermc/paper/chunk/system/scheduling/queue/RadiusAwarePrioritisedExecutor.java
index 3272f73013ea7d4efdd0ae2903925cc543be7075..7600f98cbfdefbaadf6bef8009b47cb19122a917 100644
--- a/src/main/java/io/papermc/paper/chunk/system/scheduling/queue/RadiusAwarePrioritisedExecutor.java
+++ b/src/main/java/io/papermc/paper/chunk/system/scheduling/queue/RadiusAwarePrioritisedExecutor.java
@@ -223,7 +223,7 @@ public class RadiusAwarePrioritisedExecutor {
                 // no dependencies, add straight to awaiting
                 this.awaiting.add(node);
             } else {
-                node.parents = parents;
+                node.parents = parents.size(); // Gale - forget radius-aware dependency node parents
                 // we will be added to awaiting once we have no parents
             }
         }
@@ -296,14 +296,17 @@ public class RadiusAwarePrioritisedExecutor {
             if (children != null) {
                 for (int i = 0, len = children.size(); i < len; ++i) {
                     final DependencyNode child = children.get(i);
-                    if (!child.parents.remove(node)) {
-                        throw new IllegalStateException();
-                    }
-                    if (child.parents.isEmpty()) {
+                    // Gale start - forget radius-aware dependency node parents
+                    int newParents = --child.parents;
+                    if (newParents == 0) {
+                        // Gale end - forget radius-aware dependency node parents
                         // no more dependents, we can push to awaiting
-                        child.parents = null;
                         // even if the child is purged, we need to push it so that its children will be pushed
                         this.awaiting.add(child);
+                        // Gale start - forget radius-aware dependency node parents
+                    } else if (newParents < 0) {
+                        throw new IllegalStateException();
+                        // Gale end - forget radius-aware dependency node parents
                     }
                 }
             }
@@ -315,7 +318,7 @@ public class RadiusAwarePrioritisedExecutor {
                 return ret;
             }
 
-            if (ret.parents != null) {
+            if (ret.parents != 0) { // Gale - forget radius-aware dependency node parents
                 throw new IllegalStateException();
             }
 
@@ -390,8 +393,10 @@ public class RadiusAwarePrioritisedExecutor {
         // (must hold lock on the scheduler to use)
         // null is the same as empty, we just use it so that we don't allocate the set unless we need to
         private List<DependencyNode> children;
-        // null is the same as empty, indicating that this task is considered "awaiting"
-        private ReferenceOpenHashSet<DependencyNode> parents;
+        // Gale start - forget radius-aware dependency node parents
+        // 0 indicates that this task is considered "awaiting"
+        private int parents;
+        // Gale end - forget radius-aware dependency node parents
         // false -> scheduled and not cancelled
         // true -> scheduled but cancelled
         private boolean purged;