fix: base fee (#288)

* feat: set dev genesis header base fee

Signed-off-by: Gregory Edison <[email protected]>

* feat: return early for Curie

Signed-off-by: Gregory Edison <[email protected]>

* feat: answer comments

Signed-off-by: Gregory Edison <[email protected]>

---------

Signed-off-by: Gregory Edison <[email protected]>

Author: greged93

crates/scroll/chainspec/res/genesis/dev.json

@@ -3,6 +3,7 @@
     "timestamp": "0x6490fdd2",
     "extraData": "0x",
     "gasLimit": "0x1c9c380",
+    "baseFeePerGas": "0x0",
     "difficulty": "0x0",
     "mixHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
     "coinbase": "0x0000000000000000000000000000000000000000",
@@ -83,4 +84,4 @@
     "number": "0x0",
     "gasUsed": "0x0",
     "parentHash": "0x0000000000000000000000000000000000000000000000000000000000000000"
-}
+}

crates/scroll/chainspec/src/dev.rs

@@ -18,8 +18,11 @@ use scroll_alloy_hardforks::ScrollHardfork;
 /// Includes 20 prefunded accounts with `10_000` ETH each derived from mnemonic "test test test test
 /// test test test test test test test junk".
 pub static SCROLL_DEV: LazyLock<Arc<ScrollChainSpec>> = LazyLock::new(|| {
+    // In order to have Feynman activated at block 0, we set the `baseFeePerGas` field of the devnet
+    // genesis to 0.
     let genesis = serde_json::from_str(include_str!("../res/genesis/dev.json"))
         .expect("Can't deserialize Dev testnet genesis json");
+
     ScrollChainSpec {
         inner: ChainSpec {
             chain: Chain::dev(),

crates/scroll/chainspec/src/lib.rs

@@ -281,7 +281,9 @@ fn make_genesis_header(genesis: &Genesis) -> Header {
         timestamp: genesis.timestamp,
         mix_hash: genesis.mix_hash,
         beneficiary: genesis.coinbase,
-        base_fee_per_gas: None,
+        base_fee_per_gas: genesis
+            .base_fee_per_gas
+            .map(|b| b.try_into().expect("base fee should fit in u64")),
         withdrawals_root: None,
         parent_beacon_block_root: None,
         blob_gas_used: None,

crates/scroll/evm/src/base_fee.rs

@@ -57,6 +57,13 @@ where
     ) -> Result<u64, P::Error> {
         let chain_spec = &self.0;
 
+        // Return early if Curie isn't active. This branch will be taken by the
+        // `ScrollPayloadBuilder` when executing `PayloadAttributes` that were derived from the L1
+        // (during the L1 consolidation phase of the Rollup Node).
+        if !chain_spec.is_curie_active_at_block(parent_header.number() + 1) {
+            return Ok(0);
+        }
+
         // load l2 system config contract into cache.
         let system_config_contract_address =
             chain_spec.chain_config().l1_config.l2_system_config_address;
@@ -162,6 +169,7 @@ mod tests {
     ];
 
     const CURIE_TIMESTAMP: u64 = 1719994280;
+    const CURIE_BLOCK: u64 = 7096836;
 
     #[test]
     fn test_should_return_correct_base_fee() -> Result<(), Box<dyn core::error::Error>> {
@@ -172,8 +180,11 @@ mod tests {
 
         // init the provider and parent header.
         let base_fee_provider = ScrollBaseFeeProvider::new(SCROLL_MAINNET.clone());
-        let parent_header =
-            alloy_consensus::Header { timestamp: CURIE_TIMESTAMP, ..Default::default() };
+        let parent_header = alloy_consensus::Header {
+            timestamp: CURIE_TIMESTAMP,
+            number: CURIE_BLOCK,
+            ..Default::default()
+        };
         let parent_header_ts = parent_header.timestamp();
 
         // helper closure to insert the l1 base fee in state.
@@ -231,8 +242,11 @@ mod tests {
             .unwrap()
             .as_timestamp()
             .expect("Feynman is timestamp based forked.");
-        let mut parent_header =
-            alloy_consensus::Header { timestamp: feynman_fork_ts + 1, ..Default::default() };
+        let mut parent_header = alloy_consensus::Header {
+            timestamp: feynman_fork_ts + 1,
+            number: CURIE_BLOCK + 1,
+            ..Default::default()
+        };
         let parent_header_ts = parent_header.timestamp();
 
         // for each test case, update the parent header fields and check the expected value matches.