Add cancellability to PlayerTrackEntityEvent (#8605)

patches/api/0395-Player-Entity-Tracking-Events.patch

@@ -6,25 +6,29 @@ Subject: [PATCH] Player Entity Tracking Events
 
 diff --git a/src/main/java/io/papermc/paper/event/player/PlayerTrackEntityEvent.java b/src/main/java/io/papermc/paper/event/player/PlayerTrackEntityEvent.java
 new file mode 100644
-index 0000000000000000000000000000000000000000..167be75dc616578db2df1a88f1a54b17707b3a88
+index 0000000000000000000000000000000000000000..db0a011815daf2690deb4ad2aff08227664fc6b8
 --- /dev/null
 +++ b/src/main/java/io/papermc/paper/event/player/PlayerTrackEntityEvent.java
-@@ -0,0 +1,42 @@
+@@ -0,0 +1,56 @@
 +package io.papermc.paper.event.player;
 +
 +import org.bukkit.entity.Entity;
 +import org.bukkit.entity.Player;
++import org.bukkit.event.Cancellable;
 +import org.bukkit.event.HandlerList;
 +import org.bukkit.event.player.PlayerEvent;
 +import org.jetbrains.annotations.NotNull;
 +
 +/**
 + * Is called when a {@link Player} tracks an {@link Entity}.
++ * <p>
++ * If cancelled entity is not shown to the player and interaction in both directions is not possible.
 + */
-+public class PlayerTrackEntityEvent extends PlayerEvent {
++public class PlayerTrackEntityEvent extends PlayerEvent implements Cancellable {
 +
 +    private static final HandlerList handlers = new HandlerList();
 +    private final Entity entity;
++    private boolean cancelled;
 +
 +    public PlayerTrackEntityEvent(@NotNull Player player, @NotNull Entity entity) {
 +        super(player);
@@ -51,6 +55,16 @@ index 0000000000000000000000000000000000000000..167be75dc616578db2df1a88f1a54b17
 +    public Entity getEntity() {
 +        return entity;
 +    }
++
++    @Override
++    public boolean isCancelled() {
++        return cancelled;
++    }
++
++    @Override
++    public void setCancelled(boolean cancel) {
++        this.cancelled = cancel;
++    }
 +}
 diff --git a/src/main/java/io/papermc/paper/event/player/PlayerUntrackEntityEvent.java b/src/main/java/io/papermc/paper/event/player/PlayerUntrackEntityEvent.java
 new file mode 100644

patches/server/0905-Player-Entity-Tracking-Events.patch

@@ -4,31 +4,26 @@ Date: Wed, 30 Mar 2022 18:16:52 +0200
 Subject: [PATCH] Player Entity Tracking Events
 
 
-diff --git a/src/main/java/net/minecraft/world/entity/Entity.java b/src/main/java/net/minecraft/world/entity/Entity.java
+diff --git a/src/main/java/net/minecraft/server/level/ChunkMap.java b/src/main/java/net/minecraft/server/level/ChunkMap.java
-index 32093c96a22221f17411aaf260db071f27350966..58eb0a7be2e5b4dd2aba8aebc0f7a57ff1348135 100644
+index 469083208110d5735e1bbda7a15c55a032d0e8cc..a98c134ce2ea51ae6d6f92959e57a4f0e03b0f6c 100644
---- a/src/main/java/net/minecraft/world/entity/Entity.java
+--- a/src/main/java/net/minecraft/server/level/ChunkMap.java
-+++ b/src/main/java/net/minecraft/world/entity/Entity.java
++++ b/src/main/java/net/minecraft/server/level/ChunkMap.java
-@@ -4018,9 +4018,21 @@ public abstract class Entity implements Nameable, EntityAccess, CommandSource {
+@@ -1543,9 +1543,18 @@ public class ChunkMap extends ChunkStorage implements ChunkHolder.PlayerProvider
-         EnchantmentHelper.doPostDamageEffects(attacker, target);
+                 // CraftBukkit end
+                 if (flag) {
+                     if (this.seenBy.add(player.connection)) {
++                        // Paper start - entity tracking events
++                        if (io.papermc.paper.event.player.PlayerTrackEntityEvent.getHandlerList().getRegisteredListeners().length == 0 || new io.papermc.paper.event.player.PlayerTrackEntityEvent(player.getBukkitEntity(), this.entity.getBukkitEntity()).callEvent()) {
+                         this.serverEntity.addPairing(player);
++                        }
++                        // Paper end
+                     }
+                 } else if (this.seenBy.remove(player.connection)) {
++                    // Paper start - entity tracking events
++                    if (io.papermc.paper.event.player.PlayerUntrackEntityEvent.getHandlerList().getRegisteredListeners().length > 0) {
++                        new io.papermc.paper.event.player.PlayerUntrackEntityEvent(player.getBukkitEntity(), this.entity.getBukkitEntity()).callEvent();
++                    }
++                    // Paper end
+                     this.serverEntity.removePairing(player);
                  }
  
--    public void startSeenByPlayer(ServerPlayer player) {}
-+    // Paper start
-+    public void startSeenByPlayer(ServerPlayer player) {
-+        if (io.papermc.paper.event.player.PlayerTrackEntityEvent.getHandlerList().getRegisteredListeners().length > 0) {
-+            new io.papermc.paper.event.player.PlayerTrackEntityEvent(player.getBukkitEntity(), this.getBukkitEntity()).callEvent();
-+        }
-+    }
-+    // Paper end
- 
--    public void stopSeenByPlayer(ServerPlayer player) {}
-+    // Paper start
-+    public void stopSeenByPlayer(ServerPlayer player) {
-+        if(io.papermc.paper.event.player.PlayerUntrackEntityEvent.getHandlerList().getRegisteredListeners().length > 0) {
-+            new io.papermc.paper.event.player.PlayerUntrackEntityEvent(player.getBukkitEntity(), this.getBukkitEntity()).callEvent();
-+        }
-+    }
-+    // Paper end
- 
-     public float rotate(Rotation rotation) {
-         float f = Mth.wrapDegrees(this.getYRot());

patches/server/0971-Folia-scheduler-and-owned-region-API.patch

@@ -1158,7 +1158,7 @@ index 8547e7ff2f1f5b7701fb0f3c3010c14601a5f83e..fff7ad7a45f310783ac96b44575ad3db
          this.players.remove(entityplayer);
          this.playersByName.remove(entityplayer.getScoreboardName().toLowerCase(java.util.Locale.ROOT)); // Spigot
 diff --git a/src/main/java/net/minecraft/world/entity/Entity.java b/src/main/java/net/minecraft/world/entity/Entity.java
-index c014fe8808f19195d8c26925227ff28bd6738039..ccc674a3da006fc3f6edd3b479eaa86c1cc67e90 100644
+index cf9393dd02565134a1ce428e84a9f26ac2d39a0d..e19010627a030753b08aa8451363c6bc4631bf72 100644
 --- a/src/main/java/net/minecraft/world/entity/Entity.java
 +++ b/src/main/java/net/minecraft/world/entity/Entity.java
 @@ -246,11 +246,23 @@ public abstract class Entity implements Nameable, EntityAccess, CommandSource {
@@ -1186,7 +1186,7 @@ index c014fe8808f19195d8c26925227ff28bd6738039..ccc674a3da006fc3f6edd3b479eaa86c
      @Override
      public CommandSender getBukkitSender(CommandSourceStack wrapper) {
          return this.getBukkitEntity();
-@@ -4656,6 +4668,7 @@ public abstract class Entity implements Nameable, EntityAccess, CommandSource {
+@@ -4644,6 +4656,7 @@ public abstract class Entity implements Nameable, EntityAccess, CommandSource {
              return;
          }
          // Paper end - rewrite chunk system
@@ -1194,7 +1194,7 @@ index c014fe8808f19195d8c26925227ff28bd6738039..ccc674a3da006fc3f6edd3b479eaa86c
          if (this.removalReason == null) {
              this.removalReason = reason;
          }
-@@ -4666,12 +4679,28 @@ public abstract class Entity implements Nameable, EntityAccess, CommandSource {
+@@ -4654,12 +4667,28 @@ public abstract class Entity implements Nameable, EntityAccess, CommandSource {
  
          if (reason != RemovalReason.UNLOADED_TO_CHUNK) this.getPassengers().forEach(Entity::stopRiding); // Paper - chunk system - don't adjust passenger state when unloading, it's just not safe (and messes with our logic in entity chunk unload)
          this.levelCallback.onRemove(reason);