Terralith adds nearly 100 brand-new biomes, as well as updating almost every vanilla biome with new and improved features. This mod is the successor to the original Terralith, but it has been rewritten from the ground up to provide a completely new experience. Terralith 2.0 takes that overhaul and turns it up to eleven. Minecraft 1.18 brought a massive overhaul to world generation.

It accomplishes this without adding any new blocks, making it fully compatible with vanilla clients. Terralith is a datapack (packaged as a mod for both Fabric and Forge) designed to fundamentally overhaul the overworld with new biomes and caves. The only mods required to reproduce this issue are Dynamic Trees and ModernFix.There's a Discord for Terralith if you'd like to join! You probably need to set the dynamicShape flag when initializing your block properties. I believe it is actually an oversight on your end that the cache is even used for your blocks at all, as it seems that you're intending to provide a shape based on nearby branches. This means that your block's getShape handler can get invoked with a real world rather than the fake empty world vanilla uses. The reason these issues are not visible when ModernFix isn't installed is because vanilla caches block shapes immediately upon launch, while ModernFix defers the building of this cache and runs it in the background.

on seed -8079293905500261883 with no other mods except Dynamic Trees and ModernFix installed) in other cases it seems to lead to an endless recursive loop of calling shape methods on blocks until the game crashes (see the log given in the linked issue). On some seeds this leads to the game entirely deadlocking when it tries to generate chunks (e.g. Upon further investigation, it seems that Dynamic Trees has a buggy getShape implementation for its blocks. when Dynamic Trees is installed alongside my performance mod ModernFix.

Minecraft mod 1.18