this reduces the risk of OOM during conversion of large worlds
we probably ought to limit the size of region caches for regionized worlds, but that's a problem for another time.
This has been a long-standing issue since at least 2016, and probably longer.
Heavy use of getBlock(At) could cause the cache to blow up and use all available memory.
Recently, it's become clear that unmanaged cache size is also a problem for GC, because
the large number of objects blows up the GC root buffer. At first, this causes more frequent
GC runs; later, the frequency of GC runs drops, but the performance cost of them goes up
substantially because of the sheer number of objects. We can avoid this by trimming the
cache when we detect that it's exceeded limits.
I've implemented this in such a way that failing to update blockCacheSize in new code
won't have lasting impacts, since the cache count will be recalculated during scheduled
cache cleaning anyway.
Closes#152.
This allows, for example, banning the usage of spawn eggs, without preventing opening of doors, without the need for item ID whitelists.
It also allows customizing the behaviour of item and block interactions when sneaking - it's now possible to force spawn eggs to work when sneaking, or force containers to open.
Finally, this also allows preventing any interaction at all without preventing block placement (by setting both to false). Since cancelling the event will typically prevent placement too (which might not be desired).
Side note: Blocks are now always synced when right-clicking on a block.
This differs from the previous behaviour, where the blocks were only synced when the action "failed".
However, since this change introduces a situation where the action may succeed but have different results than the client expects, it's best to just always sync blocks in this situation.
Fixes#3267
we can safely assume this for blocks (though the type info doesn't reflect it) but this is not safe to assume for random APIs that might be used by plugins.
