Fix EntityUnleashEvent not respecting cancellation

Author: Harry Bridgen

paper-server/patches/sources/net/minecraft/world/entity/Leashable.java.patch

@@ -32,24 +32,33 @@
                  }
 
                  if (broadcastPacket) {
-@@ -142,7 +_,15 @@
+@@ -142,19 +_,28 @@
 
          if (leashData != null && leashData.leashHolder != null) {
              if (!entity.canInteractWithLevel() || !leashData.leashHolder.canInteractWithLevel()) {
 -                if (level.getGameRules().get(GameRules.ENTITY_DROPS)) {
+-                    entity.dropLeash();
+-                } else {
+-                    entity.removeLeash();
+-                }
 +                // Paper start - Expand EntityUnleashEvent
 +                final org.bukkit.event.entity.EntityUnleashEvent event = new org.bukkit.event.entity.EntityUnleashEvent(
 +                    entity.getBukkitEntity(),
 +                    !entity.isAlive() ? org.bukkit.event.entity.EntityUnleashEvent.UnleashReason.PLAYER_UNLEASH : org.bukkit.event.entity.EntityUnleashEvent.UnleashReason.HOLDER_GONE,
 +                    level.getGameRules().get(GameRules.ENTITY_DROPS) && !entity.pluginRemoved
 +                );
-+                event.callEvent();
-+                if (event.isDropLeash()) { // CraftBukkit - SPIGOT-7487: Don't drop leash, when the holder was removed by a plugin
-+                    // Paper end - Expand EntityUnleashEvent
-                     entity.dropLeash();
-                 } else {
-                     entity.removeLeash();
-@@ -153,8 +_,7 @@
++                // Paper start - Fix leash event; respect cancellation
++                if (event.callEvent()) {
++                    if (event.isDropLeash()) { // CraftBukkit - SPIGOT-7487: Don't drop leash, when the holder was removed by a plugin
++                        // Paper end - Expand EntityUnleashEvent
++                        entity.dropLeash();
++                    } else {
++                        entity.removeLeash();
++                    }
++                } // Paper end - Fix leash event; respect cancellation
+             }
+ 
+             Entity leashHolder = entity.getLeashHolder();
              if (leashHolder != null && leashHolder.level() == entity.level()) {
                  double d = entity.leashDistanceTo(leashHolder);
                  entity.whenLeashedTo(leashHolder);