The previous layout and class hierarchy of the skeleton API defined
variances of the skeleton, such as the wither skeleton or the stray, as
child types of the normal skeleton variance, which is technically
incorrect, yet did not produce any specific issue as the normal skeleton
variance did not have any unique logic.
With the introduction of powdered snow in the 1.17 update, the normal
skeleton variance now has unique logic, specifically the conversion to
a stay when stuck inside powdered snow, which cannot be represented in
the current API layout due to the prior mentioned hierarchy.
This commit implements the hierarchy changes made in the bukkit
repository by representing the new hierarchy on the craftbukkit side
through the CraftAbstractSkeleton and the respective additions to the
skeleton implementation in regards to the stray conversion.
This commit does not break ABI yet breaks backwards compatibility due to
the mentioned hierarchy changes. Plugins that previously used the
Skelton interface to compute whether or not an entity is skeleton-like
through instanceOf checks will now only match the normal skeleton variance
instead of any skeleton-like entity.
This was the behaviour before the 1.16 update and made it so that any
message sent by a plugin was treated as a system message allowing the
player to disable chat messages while keeping access to commands.
After 1.16 disabling the chat also disabled any plugin output, this
restores the original behaviour.
Previously spigots chunk pdc loading logic would read the entire chunk
nbt compound into the persistent data container of the chunk instead of
just reading the "BukkitValues".
Furthermore this commit also now correctly checks if the nbt compounds
of entities, tile entities and chunks actually have a value for the
"BukkitValues" key, as the previous 'getCompound' call would always
return an instance, the null check was useless. This commit now uses
'get', which returns null if no key exists and then runs an instanceof
check to both validate a non-null instance and an NBTTagCompound
instance.
