PaperMC/patches/api/Clone-mutables-to-prevent-unexpected-issues.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Jake Potrebic <jake.m.potrebic@gmail.com>
Date: Sat, 16 Mar 2024 11:10:48 -0700
Subject: [PATCH] Clone mutables to prevent unexpected issues

There are lots of locations in the API where mutable
types are not cloned, either on return or when passed
as a parameter and assigned to a field, which can cause
unexpected behaviors. Let this be a lesson to use
immutable types for simple things Location, Vector, and
others.

diff --git a/src/main/java/org/bukkit/event/block/BlockCanBuildEvent.java b/src/main/java/org/bukkit/event/block/BlockCanBuildEvent.java
index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
--- a/src/main/java/org/bukkit/event/block/BlockCanBuildEvent.java
+++ b/src/main/java/org/bukkit/event/block/BlockCanBuildEvent.java
@@ -0,0 +0,0 @@ public class BlockCanBuildEvent extends BlockEvent {
      */
     @NotNull
     public BlockData getBlockData() {
-        return blockData;
+        return blockData.clone(); // Paper - clone because mutation isn't used
     }
 
     /**
diff --git a/src/main/java/org/bukkit/event/entity/EntityChangeBlockEvent.java b/src/main/java/org/bukkit/event/entity/EntityChangeBlockEvent.java
index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
--- a/src/main/java/org/bukkit/event/entity/EntityChangeBlockEvent.java
+++ b/src/main/java/org/bukkit/event/entity/EntityChangeBlockEvent.java
@@ -0,0 +0,0 @@ public class EntityChangeBlockEvent extends EntityEvent implements Cancellable {
      */
     @NotNull
     public BlockData getBlockData() {
-        return to;
+        return to.clone(); // Paper - clone because mutation isn't used
     }
 
     @NotNull
diff --git a/src/main/java/org/bukkit/event/entity/EntityExplodeEvent.java b/src/main/java/org/bukkit/event/entity/EntityExplodeEvent.java
index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
--- a/src/main/java/org/bukkit/event/entity/EntityExplodeEvent.java
+++ b/src/main/java/org/bukkit/event/entity/EntityExplodeEvent.java
@@ -0,0 +0,0 @@ public class EntityExplodeEvent extends EntityEvent implements Cancellable {
      */
     @NotNull
     public Location getLocation() {
-        return location;
+        return location.clone(); // Paper - clone to avoid changes
     }
 
     /**
diff --git a/src/main/java/org/bukkit/event/entity/EntityPortalEnterEvent.java b/src/main/java/org/bukkit/event/entity/EntityPortalEnterEvent.java
index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
--- a/src/main/java/org/bukkit/event/entity/EntityPortalEnterEvent.java
+++ b/src/main/java/org/bukkit/event/entity/EntityPortalEnterEvent.java
@@ -0,0 +0,0 @@ public class EntityPortalEnterEvent extends EntityEvent implements org.bukkit.ev
      */
     @NotNull
     public Location getLocation() {
-        return location;
+        return location.clone(); // Paper - clone to avoid changes
     }
 
     // Paper start
diff --git a/src/main/java/org/bukkit/event/entity/ItemDespawnEvent.java b/src/main/java/org/bukkit/event/entity/ItemDespawnEvent.java
index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
--- a/src/main/java/org/bukkit/event/entity/ItemDespawnEvent.java
+++ b/src/main/java/org/bukkit/event/entity/ItemDespawnEvent.java
@@ -0,0 +0,0 @@ public class ItemDespawnEvent extends EntityEvent implements Cancellable {
      */
     @NotNull
     public Location getLocation() {
-        return location;
+        return location.clone(); // Paper - clone to avoid changes
     }
 
     @NotNull
diff --git a/src/main/java/org/bukkit/event/vehicle/VehicleBlockCollisionEvent.java b/src/main/java/org/bukkit/event/vehicle/VehicleBlockCollisionEvent.java
index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
--- a/src/main/java/org/bukkit/event/vehicle/VehicleBlockCollisionEvent.java
+++ b/src/main/java/org/bukkit/event/vehicle/VehicleBlockCollisionEvent.java
@@ -0,0 +0,0 @@ public class VehicleBlockCollisionEvent extends VehicleCollisionEvent {
      */
     @NotNull
     public org.bukkit.util.Vector getVelocity() {
-        return velocity;
+        return velocity.clone();
     }
     // Paper end
 
diff --git a/src/main/java/org/bukkit/event/vehicle/VehicleMoveEvent.java b/src/main/java/org/bukkit/event/vehicle/VehicleMoveEvent.java
index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
--- a/src/main/java/org/bukkit/event/vehicle/VehicleMoveEvent.java
+++ b/src/main/java/org/bukkit/event/vehicle/VehicleMoveEvent.java
@@ -0,0 +0,0 @@ public class VehicleMoveEvent extends VehicleEvent {
      */
     @NotNull
     public Location getFrom() {
-        return from;
+        return from.clone(); // Paper - clone to avoid changes
     }
 
     /**
@@ -0,0 +0,0 @@ public class VehicleMoveEvent extends VehicleEvent {
      */
     @NotNull
     public Location getTo() {
-        return to;
+        return to.clone(); // Paper - clone to avoid changes
     }
 
 
diff --git a/src/main/java/org/bukkit/event/world/GenericGameEvent.java b/src/main/java/org/bukkit/event/world/GenericGameEvent.java
index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
--- a/src/main/java/org/bukkit/event/world/GenericGameEvent.java
+++ b/src/main/java/org/bukkit/event/world/GenericGameEvent.java
@@ -0,0 +0,0 @@ public class GenericGameEvent extends WorldEvent implements Cancellable {
      */
     @NotNull
     public Location getLocation() {
-        return location;
+        return location.clone(); // Paper - clone to avoid changes
     }
 
     /**
diff --git a/src/main/java/org/bukkit/event/world/SpawnChangeEvent.java b/src/main/java/org/bukkit/event/world/SpawnChangeEvent.java
index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
--- a/src/main/java/org/bukkit/event/world/SpawnChangeEvent.java
+++ b/src/main/java/org/bukkit/event/world/SpawnChangeEvent.java
@@ -0,0 +0,0 @@ public class SpawnChangeEvent extends WorldEvent {
      */
     @NotNull
     public Location getPreviousLocation() {
-        return previousLocation;
+        return previousLocation.clone(); // Paper - clone to avoid changes
     }
 
     @NotNull
diff --git a/src/main/java/org/bukkit/event/world/StructureGrowEvent.java b/src/main/java/org/bukkit/event/world/StructureGrowEvent.java
index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
--- a/src/main/java/org/bukkit/event/world/StructureGrowEvent.java
+++ b/src/main/java/org/bukkit/event/world/StructureGrowEvent.java
@@ -0,0 +0,0 @@ public class StructureGrowEvent extends WorldEvent implements Cancellable {
      */
     @NotNull
     public Location getLocation() {
-        return location;
+        return location.clone(); // Paper - clone to avoid changes
     }
 
     /**