I am writing a mod which should work on multiple versions. Some things already work as intended, but there's been one issue I couldn't resolve for over 4 hours now!

Scenario:

• I create a mod with 1.20.4 mappings
• I want to use that mod on 1.20.1 as well
• The mod uses Lnet/minecraft/client/network/ClientCommonNetworkHandler;sendPacket(Lnet/minecraft/network/packet/Packet;)V in 1.20.4 which is Lnet/minecraft/client/network/ClientPlayNetworkHandler;sendPacket(Lnet/minecraft/network/packet/Packet;)V in 1.20.1

Intermediary names:

• 1.20.1 - Lnet/minecraft/class_634;method_2883(Lnet/minecraft/class_2596;)V
• 1.20.4 - Lnet/minecraft/class_8673;method_52787(Lnet/minecraft/class_2596;)V

I tried in my code (my current goal is only to bring the mod compiled in 1.20.4 to work on 1.20.1):

        try {
            MappingResolver resolver = FabricLoader.getInstance().getMappingResolver();

            Class<?> cls = Class.forName(resolver.mapClassName("intermediary", "net.minecraft.class_634"));
            Class<?> pack = Class.forName(resolver.mapClassName("intermediary", "net.minecraft.class_2596"));

            MethodHandles.Lookup lookup = MethodHandles.publicLookup();
            MethodHandle methodHandle = lookup.findVirtual(cls,
                    resolver.mapMethodName(
                            "intermediary",
                            resolver.unmapClassName("intermediary", cls.getName()),
                            "method_2883",
                            "(Lnet/minecraft/class_2596;)V"
                    ),
                    MethodType.methodType(void.class, pack)
            );

            methodHandle.invokeExact(handler, packet);

        } catch (Throwable e) {
            throw new RuntimeException(e);
        }

I also tried usual reflection, but this also didn't work.

The issue:
No matter how I try to reference Lnet/minecraft/class_634;method_2883(Lnet/minecraft/class_2596;)V, even if the method and class resolve correctly, in the end Lnet/minecraft/class_634;method_52787(Lnet/minecraft/class_2596;)V is being called which produces NoSuchMethodError (⚠️ this, and not NoSuchMethodException which would come from reflection).

If there is any way to achieve this, or if I am doing anything wrong - in any way, I need help! 🙏

Issue resolved - there was another place in my mod calling the same method which I did not link to my MultiVersion remapper