Use a proper teleport for teleporting to entities in different
worlds.
Validate that the target entity is valid and deny spectate
requests from frozen players.
Also, make sure the entity is spawned to the client before
sending the camera packet. If the entity isn't spawned clientside
when it receives the camera packet, then the client will not
spectate the target entity.
Upstream has released updates that appears to apply and compile correctly.
This update has not been tested by PaperMC and as with ANY update, please do your own testing
Bukkit Changes:
da9ef3c5 #496: Add methods to get/set ItemStacks in EquipmentSlots
3abebc9f #492: Let Tameable extend Animals rather than Entity
941111a0 #495: Expose ItemStack and hand used in PlayerShearEntityEvent
4fe19cae #494: InventoryView - Add missing Brewing FUEL_TIME
CraftBukkit Changes:
933e9094#664: Add methods to get/set ItemStacks in EquipmentSlots
18722312#662: Expose ItemStack and hand used in PlayerShearEntityEvent