In general, the client now has an acknowledgment system that will cause block changes made by the client to be reverted correctly.
Essentially:
The client enters a "prediction" stage, where any block changes made will have its old blockstate captured (this is referred to as "server state").
If you update blocks during this stage, the client will update this captured server state as long as they're still currently predicting.
After prediction is done (via an ack packet) all captured blockstates are reverted to their captured server state.
This means that if the server actually updated a block and send a block update packet, it's correctly set, while if a block wasn't updated on the server but WAS updated on the client (server state wasn't updated), that change will be reverted.
It should be noted that this system does not yet support block entities, so those still need to be resynced when needed.
I discovered this when noticing that blocks broken outside of the player's valid interaction distance are still properly reverted, even though the server doesn't send any block updates, only an ack packet.
Upstream has released updates that appear 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:
fde5602a PR-927: Add PlayerRecipeBookSettingsChangeEvent
949ff217 PR-930: Add methods to get/set evoker fang attack delay
f6f7c79d SPIGOT-7514, PR-929: Add "Enchantment Roll" API to enchant items according to Minecraft mechanics
d40e22da PR-712: Add API to get full result of crafting items
CraftBukkit Changes:
c8feb0629 PR-1291: Improve precondition message in Entity#playEffect
482c56a00 PR-1285: Add PlayerRecipeBookSettingsChangeEvent
cdf798800 PR-1290: Add methods to get/set evoker fang attack delay
2c1b5f78f SPIGOT-7514, PR-1289: Add "Enchantment Roll" API to enchant items according to Minecraft mechanics
6aa644ae9 PR-992: Add API to get full result of crafting items
ffb1319bc PR-1287: Fix scoreboards not updating in Player#setStatistic
Upstream has released updates that appear 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:
01aa02eb PR-858: Add LivingEntity#playHurtAnimation()
9421320f PR-884: Refinements to new ban API for improved compatibility and correctness
37a60b45 SPIGOT-6455, SPIGOT-7030, PR-750: Improve ban API
4eeb174b All smithing inventories are now the new smithing inventory
f2bb168e PR-880: Add methods to get/set FallingBlock CancelDrop
e7a807fa PR-879: Add Player#sendHealthUpdate()
692b8e96 SPIGOT-7370: Remove float value conversion in plugin.yml
2d033390 SPIGOT-7403: Add direct API for waxed signs
16a08373 PR-876: Add missing Raider API and 'no action ticks'
CraftBukkit Changes:
b60a95c8c PR-1189: Add LivingEntity#playHurtAnimation()
95c335c63 PR-1226: Fix VehicleEnterEvent not being called for certain entities
0a0fc3bee PR-1227: Refinements to new ban API for improved compatibility and correctness
0d0b1e5dc Revert bad change to PathfinderGoalSit causing all cats to sit
648196070 SPIGOT-6455, SPIGOT-7030, PR-1054: Improve ban API
31fe848d6 All smithing inventories are now the new smithing inventory
9a919a143 SPIGOT-7416: SmithItemEvent not firing in Smithing Table
9f64f0d22 PR-1221: Add methods to get/set FallingBlock CancelDrop
3be9ac171 PR-1220: Add Player#sendHealthUpdate()
c1279f775 PR-1209: Clean up various patches
c432e4397 Fix Raider#setCelebrating() implementation
504d96665 SPIGOT-7403: Add direct API for waxed signs
c68c1f1b3 PR-1216: Add missing Raider API and 'no action ticks'
85b89c3dd Increase outdated build delay
Spigot Changes:
9ebce8af Rebuild patches
64b565e6 Rebuild patches
