fix: include base fee per gas for next block (#7188)

crates/anvil/src/eth/api.rs

@@ -1304,8 +1304,6 @@ impl EthApi {
  return Err(FeeHistoryError::InvalidBlockRange.into());
  }
 
- let fee_history = self.fee_history_cache.lock();
-
  let mut response = FeeHistory {
  oldest_block: U256::from(lowest),
  base_fee_per_gas: Vec::new(),
@@ -1314,37 +1312,44 @@ impl EthApi {
  base_fee_per_blob_gas: Default::default(),
  blob_gas_used_ratio: Default::default(),
  };
-
  let mut rewards = Vec::new();
- // iter over the requested block range
- for n in lowest..=highest {
- // <https://eips.ethereum.org/EIPS/eip-1559>
- if let Some(block) = fee_history.get(&n) {
- response.base_fee_per_gas.push(U256::from(block.base_fee));
- response.gas_used_ratio.push(block.gas_used_ratio);
-
- // requested percentiles
- if !reward_percentiles.is_empty() {
- let mut block_rewards = Vec::new();
- let resolution_per_percentile: f64 = 2.0;
- for p in &reward_percentiles {
- let p = p.clamp(0.0, 100.0);
- let index = ((p.round() / 2f64) * 2f64) * resolution_per_percentile;
- let reward = if let Some(r) = block.rewards.get(index as usize) {
- U256::from(*r)
- } else {
- U256::ZERO
- };
- block_rewards.push(reward);
+
+ {
+ let fee_history = self.fee_history_cache.lock();
+
+ // iter over the requested block range
+ for n in lowest..=highest {
+ // <https://eips.ethereum.org/EIPS/eip-1559>
+ if let Some(block) = fee_history.get(&n) {
+ response.base_fee_per_gas.push(U256::from(block.base_fee));
+ response.gas_used_ratio.push(block.gas_used_ratio);
+
+ // requested percentiles
+ if !reward_percentiles.is_empty() {
+ let mut block_rewards = Vec::new();
+ let resolution_per_percentile: f64 = 2.0;
+ for p in &reward_percentiles {
+ let p = p.clamp(0.0, 100.0);
+ let index = ((p.round() / 2f64) * 2f64) * resolution_per_percentile;
+ let reward = if let Some(r) = block.rewards.get(index as usize) {
+ U256::from(*r)
+ } else {
+ U256::ZERO
+ };
+ block_rewards.push(reward);
+ }
+ rewards.push(block_rewards);
  }
- rewards.push(block_rewards);
  }
  }
  }
 
  response.reward = Some(rewards);
 
  // calculate next base fee
+ // The spec states that `base_fee_per_gas` "[..] includes the next block after the
+ // newest of the returned range, because this value can be derived from the
+ // newest block"
  if let (Some(last_gas_used), Some(last_fee_per_gas)) =
  (response.gas_used_ratio.last(), response.base_fee_per_gas.last())
  {

crates/anvil/src/eth/fees.rs

@@ -198,12 +198,15 @@ impl FeeHistoryService {
  self.fee_history_limit
  }
 
+ /// Inserts a new cache entry for the given block
+ pub(crate) fn insert_cache_entry_for_block(&self, hash: B256) {
+ let (result, block_number) = self.create_cache_entry(hash);
+ self.insert_cache_entry(result, block_number);
+ }
+
  /// Create a new history entry for the block
- fn create_cache_entry(
- &self,
- hash: B256,
- elasticity: f64,
- ) -> (FeeHistoryCacheItem, Option<u64>) {
+ fn create_cache_entry(&self, hash: B256) -> (FeeHistoryCacheItem, Option<u64>) {
+ let elasticity = self.fees.elasticity();
  // percentile list from 0.0 to 100.0 with a 0.5 resolution.
  // this will create 200 percentile points
  let reward_percentiles: Vec<f64> = {
@@ -315,11 +318,9 @@ impl Future for FeeHistoryService {
 
  while let Poll::Ready(Some(notification)) = pin.new_blocks.poll_next_unpin(cx) {
  let hash = notification.hash;
- let elasticity = default_elasticity();
 
  // add the imported block.
- let (result, block_number) = pin.create_cache_entry(hash, elasticity);
- pin.insert_cache_entry(result, block_number)
+ pin.insert_cache_entry_for_block(hash);
  }
 
  Poll::Pending

crates/anvil/src/lib.rs

@@ -145,6 +145,12 @@ pub async fn spawn(mut config: NodeConfig) -> (EthApi, NodeHandle) {
  fees,
  StorageInfo::new(Arc::clone(&backend)),
  );
+ // create an entry for the best block
+ if let Some(best_block) =
+ backend.get_block(backend.best_number()).map(|block| block.header.hash_slow())
+ {
+ fee_history_service.insert_cache_entry_for_block(best_block);
+ }
 
  let filters = Filters::default();