fix: eth_feeHistory

crates/anvil/src/eth/api.rs

@@ -1313,30 +1313,11 @@ impl EthApi {
 
         response.reward = Some(rewards);
 
-        // calculate next base fee
+        // add the next block's base fee to the response
         // 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())
-        {
-            let elasticity = self.backend.elasticity();
-            let last_fee_per_gas = *last_fee_per_gas as f64;
-            if last_gas_used > &0.5 {
-                // increase base gas
-                let increase = ((last_gas_used - 0.5) * 2f64) * elasticity;
-                let new_base_fee = (last_fee_per_gas + (last_fee_per_gas * increase)) as u128;
-                response.base_fee_per_gas.push(new_base_fee);
-            } else if last_gas_used < &0.5 {
-                // decrease gas
-                let increase = ((0.5 - last_gas_used) * 2f64) * elasticity;
-                let new_base_fee = (last_fee_per_gas - (last_fee_per_gas * increase)) as u128;
-                response.base_fee_per_gas.push(new_base_fee);
-            } else {
-                // same base gas
-                response.base_fee_per_gas.push(last_fee_per_gas as u128);
-            }
-        }
+        response.base_fee_per_gas.push(self.backend.fees().base_fee());
 
         Ok(response)
     }

crates/anvil/src/eth/backend/mem/mod.rs

@@ -1055,12 +1055,12 @@ impl Backend {
             header.base_fee_per_gas.unwrap_or_default(),
         );
 
-        // notify all listeners
-        self.notify_on_new_block(header, block_hash);
-
         // update next base fee
         self.fees.set_base_fee(next_block_base_fee);
 
+        // notify all listeners
+        self.notify_on_new_block(header, block_hash);
+
         outcome
     }
 

crates/anvil/src/eth/fees.rs

@@ -174,7 +174,6 @@ impl FeeHistoryService {
 
     /// Create a new history entry for the block
     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> = {
@@ -199,10 +198,7 @@ impl FeeHistoryService {
             block_number = Some(block.header.number);
 
             let gas_used = block.header.gas_used as f64;
-            let gas_limit = block.header.gas_limit as f64;
-
-            let gas_target = gas_limit / elasticity;
-            item.gas_used_ratio = gas_used / (gas_target * elasticity);
+            item.gas_used_ratio = gas_used / block.header.gas_limit as f64;
 
             // extract useful tx info (gas_used, effective_reward)
             let mut transactions: Vec<(u128, u128)> = receipts

crates/anvil/tests/it/gas.rs

@@ -170,3 +170,25 @@ async fn test_tip_above_fee_cap() {
         .to_string()
         .contains("max priority fee per gas higher than max fee per gas"));
 }
+
+#[tokio::test(flavor = "multi_thread")]
+async fn test_can_use_fee_history() {
+    let base_fee = 50u128;
+    let (_api, handle) = spawn(NodeConfig::test().with_base_fee(Some(base_fee))).await;
+    let provider = handle.http_provider();
+
+    for _ in 0..10 {
+        let fee_history = provider.get_fee_history(1, Default::default(), &[]).await.unwrap();
+        let next_base_fee = fee_history.base_fee_per_gas.last().unwrap();
+
+        let tx = TransactionRequest::default()
+            .with_to(Address::random())
+            .with_value(U256::from(100))
+            .with_gas_price(*next_base_fee);
+        let tx = WithOtherFields::new(tx);
+
+        let receipt =
+            provider.send_transaction(tx.clone()).await.unwrap().get_receipt().await.unwrap();
+        assert!(receipt.inner.inner.is_success());
+    }
+}