The item tag is stored before executing the interaction and restored before handling the
resulting events. If the event was not canceled and the ItemStack is not modified in the
event, the new tag is set back to the new one afterwards. This is similar to the handling
of the item amount.
This fixes a bug where tools lose durability when the interaction is canceled and another bug
where tools become completely repaired when they should break but the interaction was canceled.
getDimensionId() returns the dimension id - 1. So without this patch
we would reuse an existing dimension id, if some other dimension was
unloaded before.
In Spigot this is nearly invisible because DimensionManager has no equals(),
so dimension id collisions just create 2 worlds with the same dimension.
The PaperWorldMap (Added in
https://github.com/PaperMC/Paper/blob/master/Spigot-Server-Patches/0376-Optimize-Server-World-Map.patch ) changes this - Now the dimension is overwritten if there is some collision,
what causes players to teleport to incorrect worlds, World checks will no longer work
and many more evil things.
This is the best way to get an entity when the world and its UUID are known.
It is faster than Server.getEntity(UUID) because it does not have to iterate all worlds
This event is called when an entity receives knockback by another entity. The knockback can be modified in the event. If the event is cancelled the entity is not knocked back.
HashSet sometimes uses compareTo() instead of equals() and this breaks the comparison of net.minecraft.server.NextTickListEntry (the only place where HashTreeSet is used).
In this cases duplicate entries could be added to the HashSet of HashTreeSet, because NextTickListEntry.compareTo() does not return 0, even if NextTickListEntry.equals() returns true.
ObjectOpenHashSet never uses compareTo(), so the inconsistencies of NextTickListEntry cause no problems.
Fixes https://github.com/PaperMC/Paper/issues/588
Fixes falling dragon eggs in lazy chunks fall to the block below the last empty block and replacing that block with them.
See also https://bugs.mojang.com/browse/MC-94186
Brokkonaut