In general, worldstate read/write is unacceptable during
data deserialization and is racey even in Vanilla. But in Folia,
some accesses may throw and as such we need to fix this directly.
Fixes https://github.com/PaperMC/Folia/issues/57
The returned TE may be in the world, in which case it is unsafe
for the current thread to modify or access its contents.
Fixes https://github.com/PaperMC/Folia/issues/52
This is to prevent block physics from tripping thread checks by
far exceeding the bounds of the current region. While this does
add explicit block update suppression techniques, it's better
than the server crashing.
Perform thread checks on the chunk send and warn when the
world is mismatched. I suspect that the world mismatches for
an unknown reason, but need to confirm it to chase it down.
Change overview:
- Rework limiting
- Remove mid tick updates
- Introduce consistency checks
The old limiting logic used an intervalled counter, but
did not account for possible slight changes in mid tick
invoke rate as it relied heavily on mid-tick logic. Due to
the removal of mid tick updates, it is now important that
the logic functions correctly no matter what rate it is invoked
at. The new logic directly tracks the last update time and
allocates an amount based proportional on the rate targetted,
which makes the logic call rate independent.
The removal of mid tick updates is done to eliminate recursive
call risk, and to additionally reduce the lock pressure on the
chunk system by grouping chunk loads onto one part of the tick
rather than spreading it out. The limiting rework should ensure
that this does not negatively affect rates, but it will decrease
the perceived smoothness of chunk generation/loading at low rates.
Introduce more consistency checks such as correct tick thread
and ticking-after-removal checks. Also, perform checks during the player
chunk loader tick to avoid updating potentially removed
players during the tick.
The checks are primarily made to try to hunt down a bug that
is causing the player chunk loader to double send a chunk
to a player.
Due to TPS catchup being removed, a lost tick will always
affect block breaking.
Additionally, constant low TPS would affect block breaking
in an intrusive manner to the user when there is no need
for that to occur.
The expected behavior is that the entity is only dismounted
_if_ the teleport takes place, not regardless of whether
the teleport takes place.
To adhere to the expected behavior, we need to create a new teleport
flag so that the NMS teleportAsync can perform the dismount.
Required to add some basic hacks to expose a regionstats object
in the TickRegions data class, but this ensures that the retrieval
is thread-safe and could possibly support other data exposure
for async reads.
Additionally, since DecimalFormat is not thread-safe we need
to use ThreadLocals to instantiate them. Change the format
as well to use commas to separate groups of digits when
formatting large numbers so they are easier to read.
For example, 1000 becomes 1,000.
Vanilla inserted the alive check so that dead players
could see the chunks around them, but in Folia we do not
remove dead players so chunks will still load for them.
This prevents the client from having chunks in memory it
should not.
The inventory was being cleared by removing the entity
from the world, but Folia changed the remove to be
before the entity copy which caused the new entity
to have a cleared inventory. Fix this by creating
a post-dimension copy callback that will clear
the inventory of the old entity.
Fixes https://github.com/PaperMC/Folia/issues/29
If the player moves out of range by the time the block is destroyed,
then the exception would throw and remove the player from the world
Additionally, when players fail to tick instead of removing
the player from the world, kick them to prevent a limbo state
The MinecraftServer executor will throw, and thanks
to CompletableFuture's awful exception handling
the exception was not logged or handled. Add
exception handling as well.
Fixes https://github.com/PaperMC/Folia/issues/27
The code to stop all brain tasks is required to pass the current
game time to the tasks it stops. But, when a villager is being
portalled, the copied entity does not have any running tasks. So,
we can simply return early before invoking getGameTime if there
are no running tasks.
Fixes https://github.com/PaperMC/Folia/issues/23
Now that there is no on-main task, the completion logic
for the status task is completed with the results passed
by the off-main task. Thus, the chunk system saw a non-null
throwable and assumed a fatal crash. The old on-main task
did not pass the throwable through in this case, which allowed
the chunk to re-generate.
Fixes https://github.com/PaperMC/Folia/issues/7
Before, it returned the center chunk section. Also, now instead
of approximating the center chunk from the allocated sections,
actually retrieve all chunks inside the region directly.
Now, entity/global/location schedulers implement a generic run,
runDelayed, and runAtFixedRate methods that provide a ScheduledTask
value that can be used to interact with the scheduled task.
Add also an async task scheduler that implements the same methods,
except the delays/periods are in time and not ticks, as the scheduler
is independent of the server tick process.
Additionally, throw on some unimplemented APIs now.
Mid-tick task execution acquires the ticket lock at least,
which can possibly be a significant performance bottleneck
at a high tick thread + region count. This change should reduce
the impact from scaling the region threads, but is not a fix
to the underlying issue.
The concurrent access occurred in the region merge/split logic,
as it did not own the ticket lock. To resolve this, we simply
make the ticket add/remove acquire the read lock of
the region lock.
Sometimes a region is empty, but only when the threaded regioniser
crashes. So, it should not prevent shutdown.
Additionally, only remove pending teleports after setting the
current region.
This will prevent a race condition where the region is cancelled
and immediately re-scheduled, and where this all happens while
the tick thread is blocking on tryMarkTicking.
Everyone had access to /tps for the private tests, but we cannot
trust everyone to use it responsibly for the public test
(i.e revealing coordinates of all logged in players).
In the case that the entity has a null callback, it means the
entity has not been added to the world - so, we should treat
it the same as entity#isRemoved.
This may be useful for plugins which want to perform operations
over large areas outside of the buffer zone provided by the
regionaliser, as it is not guaranteed that anything outside
of the buffer zone is owned. Then, the plugins may use
the schedulers depending on the result of the ownership
check.
This event allows plugins to perform synchronous operations before
any region will tick. Plugins will not have to worry about the
possibility of a region ticking in parallel while listening
to the event.
