com.comphenix.protocol.reflect.FieldAccessException: No field with type net.minecraft.server.v1_16_R2.ItemStack exists in class PacketPlayOutEntityEquipment.

[alexandrage]

com.comphenix.protocol.reflect.FieldAccessException: No field with type net.minecraft.server.v1_16_R2.ItemStack exists in class PacketPlayOutEntityEquipment.
at com.comphenix.protocol.reflect.StructureModifier.writeInternal(StructureModifier.java:363) ~[?:?]
at com.comphenix.protocol.reflect.StructureModifier.write(StructureModifier.java:343) ~[?:?]
at com.comphenix.packetwrapper.WrapperPlayServerEntityEquipment.setItem(WrapperPlayServerEntityEquipment.java:109) ~[?:?]

[MeFisto94]

Actually, I get a different error: No field with type net.minecraft.server.v1_16_R2.EnumItemSlot exists in class PacketPlayOutEntityEquipment.

And indeed, the protocl has changed:

private int a;
private final List<Pair<EnumItemSlot, ItemStack>> b;

Not sure if ProtocolLib supports Pair at all, I'll check that

Edit: okay, we need to wait that dmulloy2/ProtocolLib@f19bfc6 is deployed as a Snapshot.
The other question is, whether the regeneration script should be ran or whether this code change should be done manually?

[alexandrage]

This works for block setting yes getSlotStackPairLists

[JarvisCraft]

The other question is, whether the regeneration script should be ran or whether this code change should be done manually?

As I am aware, the work on new format support is done manually.

This exact fix is partly available here: #78 (although the PR seems to be incorrect as write operations seem to be missing).

Also it should be available as part of this changeset: #60 (lazily, but I am working on it as I now have some sponsoring for it).

As a temporary workaround you can either do these operations directly by modifying the underlying PacketContainer manually or either add the Draft-PR branch as a git submodule and use it for building.