Swap some nullable annotations (#9696)

patches/api/Add-EntityLoadCrossbowEvent.patch

@@ -13,26 +13,27 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +package io.papermc.paper.event.entity;
 +
 +import org.bukkit.entity.LivingEntity;
-+import org.bukkit.entity.Player;
 +import org.bukkit.event.Cancellable;
 +import org.bukkit.event.HandlerList;
 +import org.bukkit.event.entity.EntityEvent;
 +import org.bukkit.inventory.EquipmentSlot;
 +import org.bukkit.inventory.ItemStack;
++import org.jetbrains.annotations.ApiStatus;
 +import org.jetbrains.annotations.NotNull;
-+import org.jetbrains.annotations.Nullable;
 +
 +/**
 + * Called when a LivingEntity loads a crossbow with a projectile.
 + */
 +public class EntityLoadCrossbowEvent extends EntityEvent implements Cancellable {
-+    private static final HandlerList handlers = new HandlerList();
++    private static final HandlerList HANDLER_LIST = new HandlerList();
++
 +    private final ItemStack crossbow;
 +    private final EquipmentSlot hand;
 +    private boolean cancelled;
 +    private boolean consumeItem = true;
 +
-+    public EntityLoadCrossbowEvent(@NotNull LivingEntity entity, @Nullable ItemStack crossbow, @NotNull EquipmentSlot hand) {
++    @ApiStatus.Internal
++    public EntityLoadCrossbowEvent(@NotNull LivingEntity entity, @NotNull ItemStack crossbow, @NotNull EquipmentSlot hand) {
 +        super(entity);
 +        this.crossbow = crossbow;
 +        this.hand = hand;
@@ -49,7 +50,7 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +     *
 +     * @return the crossbow involved in this event
 +     */
-+    @Nullable
++    @NotNull
 +    public ItemStack getCrossbow() {
 +        return crossbow;
 +    }
@@ -99,11 +100,11 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +    @NotNull
 +    @Override
 +    public HandlerList getHandlers() {
-+        return handlers;
++        return HANDLER_LIST;
 +    }
 +
 +    @NotNull
 +    public static HandlerList getHandlerList() {
-+        return handlers;
++        return HANDLER_LIST;
 +    }
 +}

patches/api/Add-PhantomPreSpawnEvent.patch

@@ -16,6 +16,7 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +import org.bukkit.entity.Entity;
 +import org.bukkit.entity.EntityType;
 +import org.bukkit.event.entity.CreatureSpawnEvent;
++import org.jetbrains.annotations.ApiStatus;
 +import org.jetbrains.annotations.NotNull;
 +import org.jetbrains.annotations.Nullable;
 +
@@ -26,6 +27,7 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +public class PhantomPreSpawnEvent extends PreCreatureSpawnEvent {
 +    @NotNull private final Entity entity;
 +
++    @ApiStatus.Internal
 +    public PhantomPreSpawnEvent(@NotNull Location location, @NotNull Entity entity, @NotNull CreatureSpawnEvent.SpawnReason reason) {
 +        super(location, EntityType.PHANTOM, reason);
 +        this.entity = entity;
@@ -36,7 +38,7 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +     *
 +     * @return Entity
 +     */
-+    @Nullable
++    @NotNull
 +    public Entity getSpawningEntity() {
 +        return entity;
 +    }

patches/api/Add-PlayerArmorChangeEvent.patch

@@ -22,6 +22,7 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +import java.util.Collections;
 +import java.util.HashSet;
 +import java.util.Set;
++import org.jetbrains.annotations.ApiStatus;
 +import org.jetbrains.annotations.NotNull;
 +import org.jetbrains.annotations.Nullable;
 +
@@ -36,10 +37,11 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +    private static final HandlerList HANDLERS = new HandlerList();
 +
 +    @NotNull private final SlotType slotType;
-+    @Nullable private final ItemStack oldItem;
-+    @Nullable private final ItemStack newItem;
++    @NotNull private final ItemStack oldItem;
++    @NotNull private final ItemStack newItem;
 +
-+    public PlayerArmorChangeEvent(@NotNull Player player, @NotNull SlotType slotType, @Nullable ItemStack oldItem, @Nullable ItemStack newItem) {
++    @ApiStatus.Internal
++    public PlayerArmorChangeEvent(@NotNull Player player, @NotNull SlotType slotType, @NotNull ItemStack oldItem, @NotNull ItemStack newItem) {
 +        super(player);
 +        this.slotType = slotType;
 +        this.oldItem = oldItem;
@@ -61,7 +63,7 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +     *
 +     * @return old item
 +     */
-+    @Nullable
++    @NotNull
 +    public ItemStack getOldItem() {
 +        return this.oldItem;
 +    }
@@ -71,7 +73,7 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +     *
 +     * @return new item
 +     */
-+    @Nullable
++    @NotNull
 +    public ItemStack getNewItem() {
 +        return this.newItem;
 +    }
@@ -137,10 +139,10 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +        }
 +
 +        /**
-+         * Gets whether or not this material can be equipped to a slot
++         * Gets whether this material can be equipped to a slot
 +         *
 +         * @param material material to check
-+         * @return whether or not this material can be equipped
++         * @return whether this material can be equipped
 +         */
 +        public static boolean isEquipable(@NotNull Material material) {
 +            return getByMaterial(material) != null;

patches/api/Add-PlayerSignCommandPreprocessEvent.patch

@@ -33,7 +33,7 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +    private final Side side;
 +
 +    @ApiStatus.Internal
-+    public PlayerSignCommandPreprocessEvent(@NotNull Player player, @NotNull String message, @NotNull Set<Player> recipients, @NotNull Sign sign, final Side side) {
++    public PlayerSignCommandPreprocessEvent(@NotNull Player player, @NotNull String message, @NotNull Set<Player> recipients, @NotNull Sign sign, @NotNull Side side) {
 +        super(player, message, recipients);
 +        this.sign = sign;
 +        this.side = side;

patches/api/Add-WardenAngerChangeEvent.patch

@@ -19,8 +19,8 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +import org.bukkit.event.Cancellable;
 +import org.bukkit.event.HandlerList;
 +import org.bukkit.event.entity.EntityEvent;
++import org.jetbrains.annotations.ApiStatus;
 +import org.jetbrains.annotations.NotNull;
-+import org.jetbrains.annotations.Nullable;
 +
 +/**
 + * Called when a Warden's anger level has changed due to another entity.
@@ -29,13 +29,15 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 + */
 +public class WardenAngerChangeEvent extends EntityEvent implements Cancellable {
 +
-+    private static final HandlerList handlers = new HandlerList();
++    private static final HandlerList HANDLER_LIST = new HandlerList();
++
 +    private boolean cancelled;
 +    private final Entity target;
 +    private final int oldAnger;
 +    private int newAnger;
 +
-+    public WardenAngerChangeEvent(@NotNull final Warden warden, @Nullable final Entity target, final int oldAnger, final int newAnger) {
++    @ApiStatus.Internal
++    public WardenAngerChangeEvent(@NotNull final Warden warden, @NotNull final Entity target, final int oldAnger, final int newAnger) {
 +        super(warden);
 +        this.target = target;
 +        this.oldAnger = oldAnger;
@@ -43,11 +45,11 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +    }
 +
 +    /**
-+     * Gets the entity (if any) which triggered this anger update.
++     * Gets the entity which triggered this anger update.
 +     *
-+     * @return triggering entity, or null
++     * @return triggering entity
 +     */
-+    @Nullable
++    @NotNull
 +    public Entity getTarget() {
 +        return target;
 +    }
@@ -107,11 +109,11 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +    @NotNull
 +    @Override
 +    public HandlerList getHandlers() {
-+        return handlers;
++        return HANDLER_LIST;
 +    }
 +
 +    @NotNull
 +    public static HandlerList getHandlerList() {
-+        return handlers;
++        return HANDLER_LIST;
 +    }
 +}

patches/api/Added-PlayerChangeBeaconEffectEvent.patch

@@ -18,6 +18,7 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +import org.bukkit.event.HandlerList;
 +import org.bukkit.event.player.PlayerEvent;
 +import org.bukkit.potion.PotionEffectType;
++import org.jetbrains.annotations.ApiStatus;
 +import org.jetbrains.annotations.NotNull;
 +import org.jetbrains.annotations.Nullable;
 +
@@ -25,7 +26,7 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 + * Called when a player sets the effect for a beacon
 + */
 +public class PlayerChangeBeaconEffectEvent extends PlayerEvent implements Cancellable {
-+    private static final HandlerList handlers = new HandlerList();
++    private static final HandlerList HANDLER_LIST = new HandlerList();
 +
 +    private PotionEffectType primary;
 +    private PotionEffectType secondary;
@@ -34,7 +35,8 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +
 +    private boolean isCancelled;
 +
-+    public PlayerChangeBeaconEffectEvent(@NotNull Player player, @Nullable PotionEffectType primary, @Nullable PotionEffectType secondary, @Nullable Block beacon) {
++    @ApiStatus.Internal
++    public PlayerChangeBeaconEffectEvent(@NotNull Player player, @Nullable PotionEffectType primary, @Nullable PotionEffectType secondary, @NotNull Block beacon) {
 +        super(player);
 +        this.primary = primary;
 +        this.secondary = secondary;
@@ -80,9 +82,9 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +    }
 +
 +    /**
-+     * @return the beacon block associated with this event, or null if not found
++     * @return the beacon block associated with this event
 +     */
-+    @Nullable
++    @NotNull
 +    public Block getBeacon() {
 +        return beacon;
 +    }
@@ -143,11 +145,11 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +
 +    @Override
 +    public @NotNull HandlerList getHandlers() {
-+        return handlers;
++        return HANDLER_LIST;
 +    }
 +
 +    @NotNull
 +    public static HandlerList getHandlerList() {
-+        return handlers;
++        return HANDLER_LIST;
 +    }
 +}

patches/api/AnvilDamageEvent.patch

@@ -19,6 +19,7 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +import org.bukkit.event.inventory.InventoryEvent;
 +import org.bukkit.inventory.AnvilInventory;
 +import org.bukkit.inventory.InventoryView;
++import org.jetbrains.annotations.ApiStatus;
 +import org.jetbrains.annotations.NotNull;
 +import org.jetbrains.annotations.Nullable;
 +
@@ -26,11 +27,13 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 + * Called when an anvil is damaged from being used
 + */
 +public class AnvilDamagedEvent extends InventoryEvent implements Cancellable {
-+    private static final HandlerList handlers = new HandlerList();
++    private static final HandlerList HANDLER_LIST = new HandlerList();
++
 +    private boolean cancel;
 +    private DamageState damageState;
 +
-+    public AnvilDamagedEvent(@NotNull InventoryView inventory, @NotNull BlockData blockData) {
++    @ApiStatus.Internal
++    public AnvilDamagedEvent(@NotNull InventoryView inventory, @Nullable BlockData blockData) {
 +        super(inventory);
 +        this.damageState = DamageState.getState(blockData);
 +    }
@@ -92,12 +95,12 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +
 +    @NotNull
 +    public HandlerList getHandlers() {
-+        return handlers;
++        return HANDLER_LIST;
 +    }
 +
 +    @NotNull
 +    public static HandlerList getHandlerList() {
-+        return handlers;
++        return HANDLER_LIST;
 +    }
 +
 +    /**
@@ -109,7 +112,7 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +        DAMAGED(Material.DAMAGED_ANVIL),
 +        BROKEN(Material.AIR);
 +
-+        private Material material;
++        private final Material material;
 +
 +        DamageState(@NotNull Material material) {
 +            this.material = material;
@@ -154,7 +157,7 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +                    return state;
 +                }
 +            }
-+            throw new IllegalArgumentException("Material not an anvil");
++            throw new IllegalArgumentException("Material is not an anvil state");
 +        }
 +    }
 +}

patches/api/EnderDragon-Events.patch

@@ -20,17 +20,21 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +import org.bukkit.event.entity.EntityEvent;
 +
 +import java.util.Collection;
++import org.jetbrains.annotations.ApiStatus;
 +import org.jetbrains.annotations.NotNull;
-+import org.jetbrains.annotations.Nullable;
 +
 +/**
 + * Fired when a DragonFireball collides with a block/entity and spawns an AreaEffectCloud
 + */
 +public class EnderDragonFireballHitEvent extends EntityEvent implements Cancellable {
-+    @Nullable private final Collection<LivingEntity> targets;
-+    @NotNull private final AreaEffectCloud areaEffectCloud;
++    private static final HandlerList HANDLER_LIST = new HandlerList();
 +
-+    public EnderDragonFireballHitEvent(@NotNull DragonFireball fireball, @Nullable Collection<LivingEntity> targets, @NotNull AreaEffectCloud areaEffectCloud) {
++    @NotNull private final Collection<LivingEntity> targets;
++    @NotNull private final AreaEffectCloud areaEffectCloud;
++    private boolean cancelled = false;
++
++    @ApiStatus.Internal
++    public EnderDragonFireballHitEvent(@NotNull DragonFireball fireball, @NotNull Collection<LivingEntity> targets, @NotNull AreaEffectCloud areaEffectCloud) {
 +        super(fireball);
 +        this.targets = targets;
 +        this.areaEffectCloud = areaEffectCloud;
@@ -48,11 +52,9 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +    /**
 +     * The living entities hit by fireball
 +     *
-+     * May be null if no entities were hit
-+     *
 +     * @return the targets
 +     */
-+    @Nullable
++    @NotNull
 +    public Collection<LivingEntity> getTargets() {
 +        return targets;
 +    }
@@ -65,20 +67,6 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +        return areaEffectCloud;
 +    }
 +
-+    private static final HandlerList handlers = new HandlerList();
-+
-+    @NotNull
-+    public HandlerList getHandlers() {
-+        return handlers;
-+    }
-+
-+    @NotNull
-+    public static HandlerList getHandlerList() {
-+        return handlers;
-+    }
-+
-+    private boolean cancelled = false;
-+
 +    @Override
 +    public boolean isCancelled() {
 +        return cancelled;
@@ -88,6 +76,16 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +    public void setCancelled(boolean cancel) {
 +        cancelled = cancel;
 +    }
++
++    @NotNull
++    public HandlerList getHandlers() {
++        return HANDLER_LIST;
++    }
++
++    @NotNull
++    public static HandlerList getHandlerList() {
++        return HANDLER_LIST;
++    }
 +}
 diff --git a/src/main/java/com/destroystokyo/paper/event/entity/EnderDragonFlameEvent.java b/src/main/java/com/destroystokyo/paper/event/entity/EnderDragonFlameEvent.java
 new file mode 100644

patches/api/Fix-Spigot-annotation-mistakes.patch

@@ -491,6 +491,19 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
          return offers;
      }
  
+diff --git a/src/main/java/org/bukkit/event/entity/EntityTargetLivingEntityEvent.java b/src/main/java/org/bukkit/event/entity/EntityTargetLivingEntityEvent.java
+index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
+--- a/src/main/java/org/bukkit/event/entity/EntityTargetLivingEntityEvent.java
++++ b/src/main/java/org/bukkit/event/entity/EntityTargetLivingEntityEvent.java
+@@ -0,0 +0,0 @@ import org.jetbrains.annotations.Nullable;
+  * LivingEntity's.
+  */
+ public class EntityTargetLivingEntityEvent extends EntityTargetEvent {
+-    public EntityTargetLivingEntityEvent(@NotNull final Entity entity, @Nullable final LivingEntity target, @Nullable final TargetReason reason) {
++    public EntityTargetLivingEntityEvent(@NotNull final Entity entity, @Nullable final LivingEntity target, @NotNull final TargetReason reason) { // Paper
+         super(entity, target, reason);
+     }
+ 
 diff --git a/src/main/java/org/bukkit/event/entity/EntityToggleSwimEvent.java b/src/main/java/org/bukkit/event/entity/EntityToggleSwimEvent.java
 index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
 --- a/src/main/java/org/bukkit/event/entity/EntityToggleSwimEvent.java
@@ -510,6 +523,75 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
      @Override
      public void setCancelled(boolean cancel) {
          this.cancel = cancel;
+diff --git a/src/main/java/org/bukkit/event/entity/SpawnerSpawnEvent.java b/src/main/java/org/bukkit/event/entity/SpawnerSpawnEvent.java
+index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
+--- a/src/main/java/org/bukkit/event/entity/SpawnerSpawnEvent.java
++++ b/src/main/java/org/bukkit/event/entity/SpawnerSpawnEvent.java
+@@ -0,0 +0,0 @@ import org.jetbrains.annotations.NotNull;
+ public class SpawnerSpawnEvent extends EntitySpawnEvent {
+     private final CreatureSpawner spawner;
+ 
+-    public SpawnerSpawnEvent(@NotNull final Entity spawnee, @NotNull final CreatureSpawner spawner) {
++    public SpawnerSpawnEvent(@NotNull final Entity spawnee, @org.jetbrains.annotations.Nullable final CreatureSpawner spawner) { // Paper
+         super(spawnee);
+         this.spawner = spawner;
+     }
+ 
+-    @NotNull
++    /**
++     * Gets the spawner tile state, or null
++     * when the entity is spawned from a minecart
++     * spawner.
++     *
++     * @return the spawner tile state
++     */
++    @org.jetbrains.annotations.Nullable // Paper
+     public CreatureSpawner getSpawner() {
+         return spawner;
+     }
+diff --git a/src/main/java/org/bukkit/event/hanging/HangingBreakByEntityEvent.java b/src/main/java/org/bukkit/event/hanging/HangingBreakByEntityEvent.java
+index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
+--- a/src/main/java/org/bukkit/event/hanging/HangingBreakByEntityEvent.java
++++ b/src/main/java/org/bukkit/event/hanging/HangingBreakByEntityEvent.java
+@@ -0,0 +0,0 @@ import org.jetbrains.annotations.Nullable;
+ public class HangingBreakByEntityEvent extends HangingBreakEvent {
+     private final Entity remover;
+ 
+-    public HangingBreakByEntityEvent(@NotNull final Hanging hanging, @Nullable final Entity remover) {
++    public HangingBreakByEntityEvent(@NotNull final Hanging hanging, @NotNull final Entity remover) { // Paper
+         this(hanging, remover, HangingBreakEvent.RemoveCause.ENTITY);
+     }
+ 
+-    public HangingBreakByEntityEvent(@NotNull final Hanging hanging, @Nullable final Entity remover, @NotNull final HangingBreakEvent.RemoveCause cause) {
++    public HangingBreakByEntityEvent(@NotNull final Hanging hanging, @NotNull final Entity remover, @NotNull final HangingBreakEvent.RemoveCause cause) { // Paper
+         super(hanging, cause);
+         this.remover = remover;
+     }
+ 
+     /**
+      * Gets the entity that removed the hanging entity.
+-     * May be null, for example when broken by an explosion.
+      *
+      * @return the entity that removed the hanging entity
+      */
+-    @Nullable
++    @NotNull // Paper
+     public Entity getRemover() {
+         return remover;
+     }
+diff --git a/src/main/java/org/bukkit/event/inventory/HopperInventorySearchEvent.java b/src/main/java/org/bukkit/event/inventory/HopperInventorySearchEvent.java
+index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
+--- a/src/main/java/org/bukkit/event/inventory/HopperInventorySearchEvent.java
++++ b/src/main/java/org/bukkit/event/inventory/HopperInventorySearchEvent.java
+@@ -0,0 +0,0 @@ public class HopperInventorySearchEvent extends BlockEvent {
+         DESTINATION;
+     }
+ 
+-    public HopperInventorySearchEvent(@NotNull Inventory inventory, @NotNull ContainerType containerType, @NotNull Block hopper, @NotNull Block searchBlock) {
++    public HopperInventorySearchEvent(@Nullable Inventory inventory, @NotNull ContainerType containerType, @NotNull Block hopper, @NotNull Block searchBlock) { // Paper
+         super(hopper);
+         this.inventory = inventory;
+         this.containerType = containerType;
 diff --git a/src/main/java/org/bukkit/event/player/PlayerMoveEvent.java b/src/main/java/org/bukkit/event/player/PlayerMoveEvent.java
 index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
 --- a/src/main/java/org/bukkit/event/player/PlayerMoveEvent.java
@@ -523,6 +605,28 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
      public Location getTo() {
          return to;
      }
+diff --git a/src/main/java/org/bukkit/event/raid/RaidSpawnWaveEvent.java b/src/main/java/org/bukkit/event/raid/RaidSpawnWaveEvent.java
+index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
+--- a/src/main/java/org/bukkit/event/raid/RaidSpawnWaveEvent.java
++++ b/src/main/java/org/bukkit/event/raid/RaidSpawnWaveEvent.java
+@@ -0,0 +0,0 @@ public class RaidSpawnWaveEvent extends RaidEvent {
+     private final List<Raider> raiders;
+     private final Raider leader;
+ 
+-    public RaidSpawnWaveEvent(@NotNull Raid raid, @NotNull World world, @Nullable Raider leader, @NotNull List<Raider> raiders) {
++    public RaidSpawnWaveEvent(@NotNull Raid raid, @NotNull World world, @NotNull Raider leader, @NotNull List<Raider> raiders) { // Paper
+         super(raid, world);
+         this.raiders = raiders;
+         this.leader = leader;
+@@ -0,0 +0,0 @@ public class RaidSpawnWaveEvent extends RaidEvent {
+      *
+      * @return {@link Raider}
+      */
+-    @Nullable
++    @NotNull // Paper
+     public Raider getPatrolLeader() {
+         return leader;
+     }
 diff --git a/src/main/java/org/bukkit/event/vehicle/VehicleEntityCollisionEvent.java b/src/main/java/org/bukkit/event/vehicle/VehicleEntityCollisionEvent.java
 index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
 --- a/src/main/java/org/bukkit/event/vehicle/VehicleEntityCollisionEvent.java