fix(primitives): set cancun header fields if active at genesis (#4500)

crates/primitives/src/chain/spec.rs

@@ -1,13 +1,13 @@
 use crate::{
     constants::{
         EIP1559_DEFAULT_BASE_FEE_MAX_CHANGE_DENOMINATOR, EIP1559_DEFAULT_ELASTICITY_MULTIPLIER,
-        EIP1559_INITIAL_BASE_FEE, EMPTY_WITHDRAWALS,
+        EIP1559_INITIAL_BASE_FEE, EMPTY_RECEIPTS, EMPTY_TRANSACTIONS, EMPTY_WITHDRAWALS,
     },
     forkid::ForkFilterKey,
     header::Head,
     proofs::genesis_state_root,
     Address, BlockNumber, Chain, ForkFilter, ForkHash, ForkId, Genesis, Hardfork, Header,
-    PruneBatchSizes, SealedHeader, H160, H256, U256,
+    PruneBatchSizes, SealedHeader, EMPTY_OMMER_ROOT, H160, H256, U256,
 };
 use hex_literal::hex;
 use once_cell::sync::Lazy;
@@ -304,7 +304,24 @@ impl ChainSpec {
             (self.fork(Hardfork::Shanghai).active_at_timestamp(self.genesis.timestamp))
                 .then_some(EMPTY_WITHDRAWALS);
 
+        // If Cancun is activated at genesis, we set:
+        // * parent beacon block root to 0x0
+        // * blob gas used to 0x0
+        // * excess blob gas to 0x0
+        let (parent_beacon_block_root, blob_gas_used, excess_blob_gas) =
+            if self.fork(Hardfork::Cancun).active_at_timestamp(self.genesis.timestamp) {
+                (Some(H256::zero()), Some(0), Some(0))
+            } else {
+                (None, None, None)
+            };
+
         Header {
+            parent_hash: H256::zero(),
+            number: 0,
+            transactions_root: EMPTY_TRANSACTIONS,
+            ommers_hash: EMPTY_OMMER_ROOT,
+            receipts_root: EMPTY_RECEIPTS,
+            logs_bloom: Default::default(),
             gas_limit: self.genesis.gas_limit,
             difficulty: self.genesis.difficulty,
             nonce: self.genesis.nonce,
@@ -313,9 +330,12 @@ impl ChainSpec {
             timestamp: self.genesis.timestamp,
             mix_hash: self.genesis.mix_hash,
             beneficiary: self.genesis.coinbase,
+            gas_used: Default::default(),
             base_fee_per_gas,
             withdrawals_root,
-            ..Default::default()
+            parent_beacon_block_root,
+            blob_gas_used,
+            excess_blob_gas,
         }
     }
 
@@ -728,7 +748,7 @@ impl ChainSpecBuilder {
 
     /// Enable Cancun at genesis.
     pub fn cancun_activated(mut self) -> Self {
-        self = self.paris_activated();
+        self = self.shanghai_activated();
         self.hardforks.insert(Hardfork::Cancun, ForkCondition::Timestamp(0));
         self
     }
@@ -1061,13 +1081,15 @@ impl DepositContract {
 #[cfg(test)]
 mod tests {
     use crate::{
-        Address, AllGenesisFormats, Chain, ChainSpec, ChainSpecBuilder, DisplayHardforks,
-        ForkCondition, ForkHash, ForkId, Genesis, Hardfork, Head, DEV, GOERLI, H256, MAINNET,
-        SEPOLIA, U256,
+        constants::EMPTY_WITHDRAWALS, Address, AllGenesisFormats, Chain, ChainSpec,
+        ChainSpecBuilder, DisplayHardforks, ForkCondition, ForkHash, ForkId, Genesis, Hardfork,
+        Head, DEV, GOERLI, H256, MAINNET, SEPOLIA, U256,
     };
     use bytes::BytesMut;
     use ethers_core::types as EtherType;
     use reth_rlp::Encodable;
+    use std::str::FromStr;
+
     fn test_fork_ids(spec: &ChainSpec, cases: &[(Head, ForkId)]) {
         for (block, expected_id) in cases {
             let computed_id = spec.fork_id(block);
@@ -1832,4 +1854,42 @@ Post-merge hard forks (timestamp based):
         // assert that the cancun time was picked up
         assert_eq!(genesis.config.cancun_time, Some(4661));
     }
+
+    #[test]
+    fn test_default_cancun_header_forkhash() {
+        // set the gas limit from the hive test genesis according to the hash
+        let genesis = Genesis { gas_limit: 0x2fefd8u64, ..Default::default() };
+        let default_chainspec = ChainSpecBuilder::default()
+            .chain(Chain::Id(1337))
+            .genesis(genesis)
+            .cancun_activated()
+            .build();
+        let mut header = default_chainspec.genesis_header();
+
+        // set the state root to the same as in the hive test the hash was pulled from
+        header.state_root =
+            H256::from_str("0x62e2595e017f0ca23e08d17221010721a71c3ae932f4ea3cb12117786bb392d4")
+                .unwrap();
+
+        // shanghai is activated so we should have a withdrawals root
+        assert_eq!(header.withdrawals_root, Some(EMPTY_WITHDRAWALS));
+
+        // cancun is activated so we should have a zero parent beacon block root, zero blob gas
+        // used, and zero excess blob gas
+        assert_eq!(header.parent_beacon_block_root, Some(H256::zero()));
+        assert_eq!(header.blob_gas_used, Some(0));
+        assert_eq!(header.excess_blob_gas, Some(0));
+        println!("header: {:?}", header);
+
+        // check the genesis hash
+        let genesis_hash = header.hash_slow();
+        let expected_hash = H256::from(hex_literal::hex!(
+            "16bb7c59613a5bad3f7c04a852fd056545ade2483968d9a25a1abb05af0c4d37"
+        ));
+        assert_eq!(genesis_hash, expected_hash);
+
+        // check that the forkhash is correct
+        let expected_forkhash = ForkHash(hex_literal::hex!("8062457a"));
+        assert_eq!(ForkHash::from(genesis_hash), expected_forkhash);
+    }
 }