deprecate chain_status field of network handshake

client/network/src/protocol.rs

@@ -74,7 +74,7 @@ const MAX_KNOWN_BLOCKS: usize = 1024; // ~32kb per peer + LruHashSet overhead
 const MAX_KNOWN_EXTRINSICS: usize = 4096; // ~128kb per peer + overhead
 
 /// Current protocol version.
-pub(crate) const CURRENT_VERSION: u32 = 5;
+pub(crate) const CURRENT_VERSION: u32 = 6;
 /// Lowest version we support
 pub(crate) const MIN_VERSION: u32 = 3;
 

client/network/src/protocol/message.rs

@@ -252,7 +252,29 @@ pub mod generic {
  }
 
  /// Status sent on connection.
+ // TODO https:/paritytech/substrate/issues/4674: replace the `Status`
+ // struct with this one, after waiting a few releases beyond `NetworkSpecialization`'s
+ // removal (https:/paritytech/substrate/pull/4665)
+ //
+ // and set MIN_VERSION to 6.
  #[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
+ pub struct CompactStatus<Hash, Number> {
+ /// Protocol version.
+ pub version: u32,
+ /// Minimum supported version.
+ pub min_supported_version: u32,
+ /// Supported roles.
+ pub roles: Roles,
+ /// Best block number.
+ pub best_number: Number,
+ /// Best block hash.
+ pub best_hash: Hash,
+ /// Genesis block hash.
+ pub genesis_hash: Hash,
+ }
+
+ /// Status sent on connection.
+ #[derive(Debug, PartialEq, Eq, Clone, Encode)]
  pub struct Status<Hash, Number> {
  /// Protocol version.
  pub version: u32,
@@ -266,10 +288,44 @@ pub mod generic {
  pub best_hash: Hash,
  /// Genesis block hash.
  pub genesis_hash: Hash,
- /// Chain-specific status.
+ /// DEPRECATED. Chain-specific status.
  pub chain_status: Vec<u8>,
  }
 
+ impl<Hash: Decode, Number: Decode> Decode for Status<Hash, Number> {
+ fn decode<I: Input>(value: &mut I) -> Result<Self, codec::Error> {
+ const LAST_CHAIN_STATUS_VERSION: u32 = 5;
+ let compact = CompactStatus::decode(value)?;
+ let chain_status = match <Vec<u8>>::decode(value) {
+ Ok(v) => v,
+ Err(e) => if compact.version <= LAST_CHAIN_STATUS_VERSION {
+ return Err(e)
+ } else {
+ Vec::new()
+ }
+ };
+
+ let CompactStatus {
+ version,
+ min_supported_version,
+ roles,
+ best_number,
+ best_hash,
+ genesis_hash,
+ } = compact;
+
+ Ok(Status {
+ version,
+ min_supported_version,
+ roles,
+ best_number,
+ best_hash,
+ genesis_hash,
+ chain_status,
+ })
+ }
+ }
+
  /// Request block data from a peer.
  #[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
  pub struct BlockRequest<Hash, Number> {