Clone mutable types in events when changes are discarded (#10333)

patches/api/0034-EntityPathfindEvent.patch

@@ -7,7 +7,7 @@ Fires when an Entity decides to start moving to a location.
 
 diff --git a/src/main/java/com/destroystokyo/paper/event/entity/EntityPathfindEvent.java b/src/main/java/com/destroystokyo/paper/event/entity/EntityPathfindEvent.java
 new file mode 100644
-index 0000000000000000000000000000000000000000..5804497f34bac9a9b6b16c6e5decb0119467df7b
+index 0000000000000000000000000000000000000000..8267e8f1f0ade29a284831069e1268ee4b29e109
 --- /dev/null
 +++ b/src/main/java/com/destroystokyo/paper/event/entity/EntityPathfindEvent.java
 @@ -0,0 +1,87 @@
@@ -74,7 +74,7 @@ index 0000000000000000000000000000000000000000..5804497f34bac9a9b6b16c6e5decb011
 +     */
 +    @NotNull
 +    public Location getLoc() {
-+        return this.location;
++        return this.location.clone();
 +    }
 +
 +    @Override

patches/api/0076-AsyncTabCompleteEvent.patch

@@ -15,7 +15,7 @@ Co-authored-by: Aikar <aikar@aikar.co>
 
 diff --git a/src/main/java/com/destroystokyo/paper/event/server/AsyncTabCompleteEvent.java b/src/main/java/com/destroystokyo/paper/event/server/AsyncTabCompleteEvent.java
 new file mode 100644
-index 0000000000000000000000000000000000000000..e0847b6f0202bd8267c537f72a5e8c8cb7c6b1db
+index 0000000000000000000000000000000000000000..8965974988ad20fbe1d45885f20a3a98d2e9595f
 --- /dev/null
 +++ b/src/main/java/com/destroystokyo/paper/event/server/AsyncTabCompleteEvent.java
 @@ -0,0 +1,339 @@
@@ -208,7 +208,7 @@ index 0000000000000000000000000000000000000000..e0847b6f0202bd8267c537f72a5e8c8c
 +     */
 +    @Nullable
 +    public Location getLocation() {
-+        return this.location;
++        return this.location != null ? this.location.clone() : null;
 +    }
 +
 +    /**
@@ -534,7 +534,7 @@ index 0000000000000000000000000000000000000000..6f560a51277ccbd46a9142cfa057d276
 +    }
 +}
 diff --git a/src/main/java/org/bukkit/event/server/TabCompleteEvent.java b/src/main/java/org/bukkit/event/server/TabCompleteEvent.java
-index 270e6d8ad4358baa256cee5f16cff281f063ce3b..4a3451af454295ac3e1b688e6665cad9fc594c82 100644
+index 270e6d8ad4358baa256cee5f16cff281f063ce3b..b43c3cb5c88eada186d6f81712c244aaa18fb53e 100644
 --- a/src/main/java/org/bukkit/event/server/TabCompleteEvent.java
 +++ b/src/main/java/org/bukkit/event/server/TabCompleteEvent.java
 @@ -29,6 +29,13 @@ public class TabCompleteEvent extends Event implements Cancellable {
@@ -570,7 +570,7 @@ index 270e6d8ad4358baa256cee5f16cff281f063ce3b..4a3451af454295ac3e1b688e6665cad9
 +     */
 +    @org.jetbrains.annotations.Nullable
 +    public org.bukkit.Location getLocation() {
-+        return loc;
++        return this.loc != null ? this.loc.clone() : null;
 +    }
 +    // Paper end
 +

patches/api/0082-PreCreatureSpawnEvent.patch

@@ -16,7 +16,7 @@ See: https://github.com/PaperMC/Paper/issues/917
 
 diff --git a/src/main/java/com/destroystokyo/paper/event/entity/PreCreatureSpawnEvent.java b/src/main/java/com/destroystokyo/paper/event/entity/PreCreatureSpawnEvent.java
 new file mode 100644
-index 0000000000000000000000000000000000000000..1d582118f19a41b499ee73b5e27ddb66ed34f06b
+index 0000000000000000000000000000000000000000..633ef4dcc701916f2dbfefbbebd5994f93ffc2a4
 --- /dev/null
 +++ b/src/main/java/com/destroystokyo/paper/event/entity/PreCreatureSpawnEvent.java
 @@ -0,0 +1,109 @@
@@ -64,7 +64,7 @@ index 0000000000000000000000000000000000000000..1d582118f19a41b499ee73b5e27ddb66
 +     */
 +    @NotNull
 +    public Location getSpawnLocation() {
-+        return this.location;
++        return this.location.clone();
 +    }
 +
 +    /**

patches/api/0142-Add-source-block-constructor-and-getChangedBlockData.patch

@@ -6,7 +6,7 @@ Subject: [PATCH] Add source block constructor and getChangedBlockData() to
 
 
 diff --git a/src/main/java/org/bukkit/event/block/BlockPhysicsEvent.java b/src/main/java/org/bukkit/event/block/BlockPhysicsEvent.java
-index e3a5f5824ed882058f5bac5003f66ce79733a868..1d496e5a3d1541bf0a257a4358b3943fd6415204 100644
+index e3a5f5824ed882058f5bac5003f66ce79733a868..b23686d2e452dc0b8bde453b4a375f424cb7504a 100644
 --- a/src/main/java/org/bukkit/event/block/BlockPhysicsEvent.java
 +++ b/src/main/java/org/bukkit/event/block/BlockPhysicsEvent.java
 @@ -32,6 +32,13 @@ public class BlockPhysicsEvent extends BlockEvent implements Cancellable {
@@ -46,7 +46,7 @@ index e3a5f5824ed882058f5bac5003f66ce79733a868..1d496e5a3d1541bf0a257a4358b3943f
 +     */
 +    @NotNull
 +    public BlockData getChangedBlockData() {
-+        return changed;
++        return changed.clone();
 +    }
 +    // Paper end
 +

patches/api/0155-PreSpawnerSpawnEvent.patch

@@ -12,7 +12,7 @@ Dropped as it does not apply due to the earlier PreCreatureSpawnEvent patch not
 
 diff --git a/src/main/java/com/destroystokyo/paper/event/entity/PreSpawnerSpawnEvent.java b/src/main/java/com/destroystokyo/paper/event/entity/PreSpawnerSpawnEvent.java
 new file mode 100644
-index 0000000000000000000000000000000000000000..9a450a0095ed0aa9c92655c2f4e5732bccdd59c9
+index 0000000000000000000000000000000000000000..2910f0bf929d918c86510f29d9361bbc19411256
 --- /dev/null
 +++ b/src/main/java/com/destroystokyo/paper/event/entity/PreSpawnerSpawnEvent.java
 @@ -0,0 +1,29 @@
@@ -42,6 +42,6 @@ index 0000000000000000000000000000000000000000..9a450a0095ed0aa9c92655c2f4e5732b
 +
 +    @NotNull
 +    public Location getSpawnerLocation() {
-+        return this.spawnerLocation;
++        return this.spawnerLocation.clone();
 +    }
 +}

patches/api/0158-Turtle-API.patch

@@ -65,7 +65,7 @@ index 0000000000000000000000000000000000000000..cfbc8aaf862ac90e794ee38bf8a6cb9e
 +}
 diff --git a/src/main/java/com/destroystokyo/paper/event/entity/TurtleLayEggEvent.java b/src/main/java/com/destroystokyo/paper/event/entity/TurtleLayEggEvent.java
 new file mode 100644
-index 0000000000000000000000000000000000000000..e917e64e8ea266a3fc7387c42aad95927f0f0501
+index 0000000000000000000000000000000000000000..3029e406cd684efb5645e38711dff9c0bb7b01e4
 --- /dev/null
 +++ b/src/main/java/com/destroystokyo/paper/event/entity/TurtleLayEggEvent.java
 @@ -0,0 +1,92 @@
@@ -116,7 +116,7 @@ index 0000000000000000000000000000000000000000..e917e64e8ea266a3fc7387c42aad9592
 +     */
 +    @NotNull
 +    public Location getLocation() {
-+        return this.location;
++        return this.location.clone();
 +    }
 +
 +    /**
@@ -163,7 +163,7 @@ index 0000000000000000000000000000000000000000..e917e64e8ea266a3fc7387c42aad9592
 +}
 diff --git a/src/main/java/com/destroystokyo/paper/event/entity/TurtleStartDiggingEvent.java b/src/main/java/com/destroystokyo/paper/event/entity/TurtleStartDiggingEvent.java
 new file mode 100644
-index 0000000000000000000000000000000000000000..5cdc6b0c3db43279e2bb8043922b31f750ddb3f5
+index 0000000000000000000000000000000000000000..7a2fa4a11b47e4982d1644830d7e28f12b4378ec
 --- /dev/null
 +++ b/src/main/java/com/destroystokyo/paper/event/entity/TurtleStartDiggingEvent.java
 @@ -0,0 +1,66 @@
@@ -210,7 +210,7 @@ index 0000000000000000000000000000000000000000..5cdc6b0c3db43279e2bb8043922b31f7
 +     */
 +    @NotNull
 +    public Location getLocation() {
-+        return this.location;
++        return this.location.clone();
 +    }
 +
 +    @Override

patches/api/0168-BlockDestroyEvent.patch

@@ -12,10 +12,10 @@ This can replace many uses of BlockPhysicsEvent
 
 diff --git a/src/main/java/com/destroystokyo/paper/event/block/BlockDestroyEvent.java b/src/main/java/com/destroystokyo/paper/event/block/BlockDestroyEvent.java
 new file mode 100644
-index 0000000000000000000000000000000000000000..d0421a4cbcb672cc06b40ad41fc06a67f6d2dbbb
+index 0000000000000000000000000000000000000000..c0742b58ca2c098c27394915b624889ece1a9168
 --- /dev/null
 +++ b/src/main/java/com/destroystokyo/paper/event/block/BlockDestroyEvent.java
-@@ -0,0 +1,123 @@
+@@ -0,0 +1,122 @@
 +package com.destroystokyo.paper.event.block;
 +
 +import org.bukkit.block.Block;
@@ -79,9 +79,8 @@ index 0000000000000000000000000000000000000000..d0421a4cbcb672cc06b40ad41fc06a67
 +    /**
 +     * @return The new state of this block (Air, or a Fluid type)
 +     */
-+    @NotNull
++    public @NotNull BlockData getNewState() {
-+    public BlockData getNewState() {
++        return this.newState.clone();
-+        return this.newState;
 +    }
 +
 +    /**

patches/api/0247-Add-StructuresLocateEvent.patch

@@ -176,7 +176,7 @@ index 0000000000000000000000000000000000000000..1ac3369455972aeb1ade5dc023d1f818
 +}
 diff --git a/src/main/java/io/papermc/paper/event/world/StructuresLocateEvent.java b/src/main/java/io/papermc/paper/event/world/StructuresLocateEvent.java
 new file mode 100644
-index 0000000000000000000000000000000000000000..be86894561ff808d911e123b09bda72c9ed09185
+index 0000000000000000000000000000000000000000..582af444b058708638683e7d6f9b79685c04c061
 --- /dev/null
 +++ b/src/main/java/io/papermc/paper/event/world/StructuresLocateEvent.java
 @@ -0,0 +1,213 @@
@@ -241,7 +241,7 @@ index 0000000000000000000000000000000000000000..be86894561ff808d911e123b09bda72c
 +     * @return {@link Location} where search begins
 +     */
 +    public @NotNull Location getOrigin() {
-+        return this.origin;
++        return this.origin.clone();
 +    }
 +
 +    /**

patches/api/0260-Add-worldborder-events.patch

@@ -202,7 +202,7 @@ index 0000000000000000000000000000000000000000..a44964593b7f78c5086dc4928e75ad89
 +}
 diff --git a/src/main/java/io/papermc/paper/event/world/border/WorldBorderCenterChangeEvent.java b/src/main/java/io/papermc/paper/event/world/border/WorldBorderCenterChangeEvent.java
 new file mode 100644
-index 0000000000000000000000000000000000000000..a90f67e902c6ae35b2399e6f72a3ff8a5c15d05a
+index 0000000000000000000000000000000000000000..dd96dcc0dd68d71bf27c758ed496153d434fb386
 --- /dev/null
 +++ b/src/main/java/io/papermc/paper/event/world/border/WorldBorderCenterChangeEvent.java
 @@ -0,0 +1,79 @@
@@ -242,7 +242,7 @@ index 0000000000000000000000000000000000000000..a90f67e902c6ae35b2399e6f72a3ff8a
 +     */
 +    @NotNull
 +    public Location getOldCenter() {
-+        return this.oldCenter;
++        return this.oldCenter.clone();
 +    }
 +
 +    /**

patches/api/0468-Clone-mutables-to-prevent-unexpected-issues.patch

@@ -0,0 +1,151 @@
+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 08d09c2a92d8aa6adf6610cc05905d58a76fce1f..c74ac0cb004aa219ce2f761969a4bb46cb7c9160 100644
+--- a/src/main/java/org/bukkit/event/block/BlockCanBuildEvent.java
++++ b/src/main/java/org/bukkit/event/block/BlockCanBuildEvent.java
+@@ -102,7 +102,7 @@ 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 1a9575ad4c81aefa5ef0b927f6ac8f7064b55c49..24e1a49e48dd8f9eb2515b2ffe472a0c4d2bc09b 100644
+--- a/src/main/java/org/bukkit/event/entity/EntityChangeBlockEvent.java
++++ b/src/main/java/org/bukkit/event/entity/EntityChangeBlockEvent.java
+@@ -61,7 +61,7 @@ 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 099efafa14c10910e4ed04abb1823f0c1a96b6a6..8506fa03293c575c35b55b052224807470fdbd98 100644
+--- a/src/main/java/org/bukkit/event/entity/EntityExplodeEvent.java
++++ b/src/main/java/org/bukkit/event/entity/EntityExplodeEvent.java
+@@ -59,7 +59,7 @@ 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 6818e9f0ba32ca1a1e612703f7526b29f5a6438f..e4e3d2e22c28ef251d76c48ade267b4eb3749e7d 100644
+--- a/src/main/java/org/bukkit/event/entity/EntityPortalEnterEvent.java
++++ b/src/main/java/org/bukkit/event/entity/EntityPortalEnterEvent.java
+@@ -24,7 +24,7 @@ public class EntityPortalEnterEvent extends EntityEvent {
+      */
+     @NotNull
+     public Location getLocation() {
+-        return location;
++        return location.clone(); // Paper - clone to avoid changes
+     }
+ 
+     @NotNull
+diff --git a/src/main/java/org/bukkit/event/entity/ItemDespawnEvent.java b/src/main/java/org/bukkit/event/entity/ItemDespawnEvent.java
+index 6fc66197eb2c5d59c70d8d028b7963748371edbe..2bb29fa449cd6c90b52d2786ed15b6154d591607 100644
+--- a/src/main/java/org/bukkit/event/entity/ItemDespawnEvent.java
++++ b/src/main/java/org/bukkit/event/entity/ItemDespawnEvent.java
+@@ -46,7 +46,7 @@ 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 d0a437bd8aeec18f800893f51ece06deb0c8972c..50fad23cf4d9f591b12a9eaebeb4e26f18e8528d 100644
+--- a/src/main/java/org/bukkit/event/vehicle/VehicleBlockCollisionEvent.java
++++ b/src/main/java/org/bukkit/event/vehicle/VehicleBlockCollisionEvent.java
+@@ -31,7 +31,7 @@ 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 7bfb84d3948c773e943374316ea25a19288ec7d0..fc4cf7b21b24fe38617fa150f697bc29da76754e 100644
+--- a/src/main/java/org/bukkit/event/vehicle/VehicleMoveEvent.java
++++ b/src/main/java/org/bukkit/event/vehicle/VehicleMoveEvent.java
+@@ -27,7 +27,7 @@ public class VehicleMoveEvent extends VehicleEvent {
+      */
+     @NotNull
+     public Location getFrom() {
+-        return from;
++        return from.clone(); // Paper - clone to avoid changes
+     }
+ 
+     /**
+@@ -37,7 +37,7 @@ 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 2a2a329877d8da45c2d6afecf78ce88d52635cad..fb975fefc74d8c9746cab4c02860f55654cf92f7 100644
+--- a/src/main/java/org/bukkit/event/world/GenericGameEvent.java
++++ b/src/main/java/org/bukkit/event/world/GenericGameEvent.java
+@@ -49,7 +49,7 @@ 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 9ce93d00935446589cb2bb970cb540d109616e85..73997ae04ff39ac3984c59de32aaced9eb72ce16 100644
+--- a/src/main/java/org/bukkit/event/world/SpawnChangeEvent.java
++++ b/src/main/java/org/bukkit/event/world/SpawnChangeEvent.java
+@@ -25,7 +25,7 @@ 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 7af8d6e51c824cf0592b722b834f1d4986e3cc08..783e74bc382f0f6d24203fde7b811f588a674731 100644
+--- a/src/main/java/org/bukkit/event/world/StructureGrowEvent.java
++++ b/src/main/java/org/bukkit/event/world/StructureGrowEvent.java
+@@ -39,7 +39,7 @@ public class StructureGrowEvent extends WorldEvent implements Cancellable {
+      */
+     @NotNull
+     public Location getLocation() {
+-        return location;
++        return location.clone(); // Paper - clone to avoid changes
+     }
+ 
+     /**