In Forge 1.21.4, runClient gets a NoSuchMethodError. This error comes from a couple of classes that have a function with return type int and the name pSize(). The functions return a List object defined in the class's pSize() return value, pSize() being an inexistent function on List objects.

The classes in question are the following:

• net.minecraft.core.NonNullList
• net.minecraft.client.gui.components.AbstractSelectionList.Trackedlist

However, the rest of the classes that have a pSize() method implement it correctly, returning List.length, List.size(), 0L or an Exception.