add version byte prefix to group id

Author: dknopik

beacon_node/lighthouse_network/src/types/partial.rs

@@ -6,9 +6,9 @@ use ssz_types::VariableList;
 use std::collections::HashSet;
 use std::fmt::Debug;
 use std::sync::Arc;
-use types::EthSpec;
 use types::data::partial_data_column_sidecar::{CellBitmap, PartialDataColumn};
 use types::partial_data_column_sidecar::PartialDataColumnSidecar;
+use types::{EthSpec, Hash256};
 
 pub type HeaderSentSet = Arc<Mutex<HashSet<PeerId>>>;
 
@@ -102,7 +102,10 @@ impl<E: EthSpec> From<CellBitmap<E>> for CellBitmapMetadata<E> {
 
 impl<E: EthSpec> Partial for OutgoingPartialColumn<E> {
     fn group_id(&self) -> Vec<u8> {
-        self.partial_column.block_root.as_slice().to_vec()
+        let mut group_id = Vec::with_capacity(Hash256::len_bytes() + 1);
+        group_id.push(0);
+        group_id.extend_from_slice(self.partial_column.block_root.as_slice());
+        group_id
     }
 
     fn metadata(&self) -> Vec<u8> {

beacon_node/lighthouse_network/src/types/pubsub.rs

@@ -427,7 +427,10 @@ pub fn decode_partial<E: EthSpec>(
 ) -> Result<PartialDataColumn<E>, String> {
     match topic.kind() {
         GossipKind::DataColumnSidecar(id) => {
-            let block_root = Hash256::from_ssz_bytes(group)
+            if group.first() != Some(&0) {
+                return Err(format!("Unknown data column format: {:?}", group.first()));
+            }
+            let block_root = Hash256::from_ssz_bytes(&group[1..])
                 .map_err(|e| format!("Error decoding group: {:?}", e))?;
             let sidecar = PartialDataColumnSidecar::from_ssz_bytes(data)
                 .map_err(|e| format!("Error decoding sidecar: {:?}", e))?;