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Fix Concurrency issue in WeightedList

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if multiple threads from worldgen sort at same time, it will crash.
So make a copy of the list for sorting purposes.

Fixes #3732
Fixes #3824
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Aikar 2020-07-06 18:38:10 -04:00
parent 409b47742f
commit e588fd94a8
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Spigot-Server-Patches/0540-Fix-Concurrency-issue-in-WeightedList.patch Normal file
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@ -0,0 +1,95 @@
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Mon, 6 Jul 2020 18:36:41 -0400
Subject: [PATCH] Fix Concurrency issue in WeightedList
if multiple threads from worldgen sort at same time, it will crash.
So make a copy of the list for sorting purposes.
diff --git a/src/main/java/net/minecraft/server/WeightedList.java b/src/main/java/net/minecraft/server/WeightedList.java
index 73e5969b2a15f1639b6285286820e9f7871c7db8..b4e871140e7a0ab5e402e415ea4ff04605157d54 100644
--- a/src/main/java/net/minecraft/server/WeightedList.java
+++ b/src/main/java/net/minecraft/server/WeightedList.java
@@ -14,7 +14,7 @@ import java.util.stream.Stream;
public class WeightedList<U> {
- protected final List<WeightedList.a<U>> a;
+ protected final List<WeightedList.a<U>> list; // Paper - decompile conflict
private final Random b;
public WeightedList() {
@@ -23,17 +23,17 @@ public class WeightedList<U> {
private WeightedList(List<WeightedList.a<U>> list) {
this.b = new Random();
- this.a = Lists.newArrayList(list);
+ this.list = Lists.newArrayList(list); // Paper - decompile conflict
}
public static <U> Codec<WeightedList<U>> a(Codec<U> codec) {
- return WeightedList.a.a(codec).listOf().xmap(WeightedList::new, (weightedlist) -> {
- return weightedlist.a;
+ return WeightedList.a.a(codec).listOf().xmap(WeightedList::new, (weightedlist) -> { // Paper - decompile conflict
+ return weightedlist.list; // Paper - decompile conflict
});
}
public WeightedList<U> a(U u0, int i) {
- this.a.add(new WeightedList.a<>(u0, i));
+ this.list.add(new WeightedList.a<>(u0, i)); // Paper - decompile conflict
return this;
}
@@ -42,21 +42,20 @@ public class WeightedList<U> {
}
public WeightedList<U> a(Random random) {
- this.a.forEach((weightedlist_a) -> {
- weightedlist_a.a(random.nextFloat());
- });
- this.a.sort(Comparator.comparingDouble((object) -> {
- return ((WeightedList.a) object).c();
- }));
- return this;
+ // Paper start - make concurrent safe, work off a clone of the list
+ java.util.ArrayList<WeightedList.a<U>> list = new java.util.ArrayList<WeightedList.a<U>>(this.list);
+ list.forEach((weightedlist_a) -> weightedlist_a.a(random.nextFloat()));
+ list.sort(Comparator.comparingDouble(a::c));
+ return new WeightedList<>(list);
+ // Paper end
}
public boolean b() {
- return this.a.isEmpty();
+ return this.list.isEmpty(); // Paper - decompile conflict
}
public Stream<U> c() {
- return this.a.stream().map(WeightedList.a::a);
+ return this.list.stream().map(WeightedList.a::a); // Paper - decompile conflict
}
public U b(Random random) {
@@ -64,7 +63,7 @@ public class WeightedList<U> {
}
public String toString() {
- return "WeightedList[" + this.a + "]";
+ return "WeightedList[" + this.list + "]"; // Paper - decompile conflict
}
public static class a<T> {
@@ -98,11 +97,7 @@ public class WeightedList<U> {
return new Codec<WeightedList.a<E>>() {
public <T> DataResult<Pair<WeightedList.a<E>, T>> decode(DynamicOps<T> dynamicops, T t0) {
Dynamic<T> dynamic = new Dynamic(dynamicops, t0);
- OptionalDynamic optionaldynamic = dynamic.get("data");
- Codec codec1 = codec;
-
- codec.getClass();
- return optionaldynamic.flatMap(codec1::parse).map((object) -> {
+ return dynamic.get("data").flatMap(codec::parse).map((object) -> { // Paper - decompile error
return new WeightedList.a<>(object, dynamic.get("weight").asInt(1));
}).map((weightedlist_a) -> {
return Pair.of(weightedlist_a, dynamicops.empty());