mb_strlen() is O(n), whereas strlen() is O(1). If we receive very large chat messages (e.g. 2 MB), mb_strlen() will take a very long time to return a result (around 8ms on my machine).
Since the max size of a UTF-8 character is 4 bytes (according to standard), we can use strlen() with 4x the char limit to gate it and prevent this from happening.
Due to the way positions are updated over the network, we only see the end result of a movement and not its preceding actions. In addition, we don't know for sure whether the MCPE collision checks work the same exact way as PM.
TL;DR: It's possible for the client to capture and send a movement frame after they collided with a step and then already moved forward from it some distance, resulting in a weird arc pattern.
This PR checks the range between the old and new positions for collision boxes to ensure that all possible areas are checked for detecting fall damage.
This has been tested and successfully resolves various issues involving running down stairs:
- missing sounds
- random fall damage
avoid the overhead incurred by clear() and setItem(), because in internalSetContents(), we already have no listeners or viewers to talk to anyway, so this is just spamming shit into /dev/null.
occasionally Windows will randomly decide to deny us access to rename the file for no reason whatsoever. If this happens, we attempt an old-style copy and delete.
If the rename failed for a legit reason, the copy and delete should also fail and generate an error message. If it was Windows being a spaz, it should work normally without errors.
this->size refers to the scaled height, but the client wants the base (unscaled) size in these properties.
This caused immense lag when, for example, setting the scale of a player to 10, because their collision box would become 180 by 60, instead of the expected 18 by 6.
this was caused by 083a1e1ff6b6ff5c0c1ba14250d2b026af103b90.
This was discovered by a new PHPStan rule I'm working on, which disallows overwriting the values of parameter variables. During the refactor of this function to correct the error, another error appeared: Variable might not be defined.
This is yet another excellent example of why mutability is bad.
WE FINALLY FUCKING FOUND IT
This took several years to identify because PHP's exception stack traces don't show the actual values of parameters, but rather the values of the variables they were assigned to.
This means that if the parameter variable is mutated, the exception trace will show the value of the variable inside the function, not the value that was actually passed.
