57057f8d39
Current code is using u8 which does not have any type-safety and can contain invalid values: https://github.com/solana-labs/solana/blob/66fa062f1/ledger/src/shred.rs#L167 Checks for invalid shred-types are scattered through the code: https://github.com/solana-labs/solana/blob/66fa062f1/ledger/src/blockstore.rs#L849-L851 https://github.com/solana-labs/solana/blob/66fa062f1/ledger/src/shred.rs#L346-L348 The commit uses enum for shred type with #[repr(u8)]. Backward compatibility is maintained by implementing Serialize and Deserialize compatible with u8, and adding a test to assert that.