Introduction
This PR is a second attempt at improving movement processing to fix#1215 , #2730 and more.
This is significantly less complex than the previous attempt #2646 -- it gets rid of the movement buffering system entirely and instead relies on a simple rate limit counter to restrict on-the-fly movement processing.
Movement is rate limited to a max average of 2 per tick. It allows up to 5 seconds' backlog to accommodate network lag. The rate limit counter is increased by 2 per tick and decreased once for every movement processed. This prevents movement processing being abused for denial of service attacks.
Changes
API changes
This PR, while obviously highly beneficial for most current users, poses some BC-breaking issues because of changes to the internal Player API.
Player->processMovement() (protected) has been removed. This is a BC concern for custom player classes which overrode it and called it as a parent. In addition, child implementations won't be called every tick any more, which could break some custom movement processing systems.
Player->newPosition (protected) has been removed. This internal field may have been accessed by custom movement implementations.
Player->isTeleporting (protected) has been removed. BC concern is same as previous point.
Player->getNextPosition() (public) has been @deprecated.
Added the following protected Player class members:
int $moveRateLimit
?Vector3 $forceMoveSync
handleMovement()
processMostRecentMovements()
revertMovement()
Behavioural changes
Player movement is now subject to less rubberbanding and has more reliable behaviour.
this reduces the temptation to use it in high-level code, as well as making syncNetworkData() more useful (now it can export to many data collections, which means we can start to think about having a property cache per network session, which is more flexible)
Now, blocks do not respond to silk touch unless specifically opted into. Since this always involves custom drops in one way or another, it's easy enough to figure out which blocks need to be marked for silk touch - anything that overrides getDrops, getDropsForCompatibleTool or getSilkTouchDrops is a block which _might_ need to be flagged. Using these criteria to reduce the number of blocks needing to be checked, I was able to manually invert the behaviour as needed.
This fixes reoccurring bugs with blocks erroneously dropping themselves whenever new blocks are added and someone forgot to set that flag, granting players access to internal blocks with strange behaviour.
