if the worker selected previously had a generator registered, but has since been shutdown, the workerStartHook that cleans up generatorRegisteredWorkers won't yet have been called.
This results in the worker being started by the submission of PopulationTask, and the generator doesn't get preemptively registered.
if this happened, the index would stay set in activeChunkPopulationTasks, eventually causing the generation queue to jam up completely and non-forced generation to come to a standstill.
When profiling this, I noticed that we spend a stupidly large amount of time creating useless Position objects in the case of update=true, because Vector3->sides() calls Position->getSide(), which calls Position::fromObject(parent::getSide()). This is stupid because the update logic doesn't require Positions anywhere (as evidenced by this change needing no other alterations.
A rough profile shows that this improves setBlock() performance by about 25% in the update=true case, which is a pretty big margin.
As an added bonus, it gets rid of some unrealized cyclic dependencies in World->changedBlocks.
if the request/cancel/re-request happens all in the time before the queue gets drained, chunk hashes may appear multiple times in the queue. We don't want to process them twice if this happens (although it's mostly harmless anyway).
this could happen if a plugin calls setPopulated(true) on a chunk after a request for its population landed in the queue, but before it actually got processed. In that case, the promise would never get fulfilled.
this does not indicate a failure; it indicates that the chunk has already been successfully populated.
In this case, we shouldn't be putting the task back on the queue.
This is skirting around the real bug, which is that requestChunkPopulation() doesn't check if the target chunk is already populated before it creates a new promise that it will be.
this allows chunks locked for population to be modified. If the PopulationTask detects that the chunk was modified during the onCompletion(), the result of the population will be discarded and rescheduled, so that it includes user modifications.
tiles may be deleted in the following circumstances:
1) the target block in the new chunk doesn't expect a tile
2) the target block in the new chunk expects a different type of tile (responsibility of the plugin developer to create the new tile)
3) there's already a tile in the target chunk which conflicts with the old one
In all other cases, the tile will be transferred.
This resolves a large number of unintentional bugs caused by world editors replacing chunks without setting the deleteTilesAndEntities parameter to false (even the core itself does it).
closes#4520
entities exist completely independently from chunks now, so there is no need to interact with them whatsoever.
As I wrote in #4520, there's no sense in deleting entities here, since a chunk replacement is essentially just a mass block update.
On that theme, it might be a good idea to call Entity->onNearbyBlockChange() for all entities in the target and adjacent chunks when replacing a chunk, to ensure that they get the proper movement updates.
isChunkGenerated() merely checks if the chunk can be loaded from disk, if it's not in the runtime cache already.
This is pointless in all of these cases, because the check is prefaced by an isChunkLoaded() check, which already limits the possibility anyway. If the chunk is not generated, it'll also be considered not loaded.
this raises false-positives during shutdown if players were online.
The fact that the player entity leans on the World to clean up after it is slightly problematic, but I'm not sure what else to do about it for now.
this allows entities to exist outside of generated chunks, with one caveat: they won't be saved in such cases.
Obviously, for player entities, this doesn't matter.
fixes#3947
this fixes 2 problems:
1) Blocks which set themselves to something else during onNearbyBlockChange() would not receive any block update
2) A memory leak when blocks in unloaded chunks were scheduled for an update.
I'm a little uneasy about this change, because there must have been some reason why I put this at the end of the block and not at the start, but whatever it is, I can't reason about it, and there's reasons not to put it at the end too.
the only reason to use getCollidingEntities() instead of getNearbyEntities() is if you have an entity that may or may not be collidable depending on certain conditions.
Really, I don't think this logic belongs in World at all, but for now it has to stay, because some other stuff depends on it.
