From 03b74657bdbd2340d70c8a1dbc4576014cbc6921 Mon Sep 17 00:00:00 2001
From: nicolas <48695862+merklefruit@users.noreply.github.com>
Date: Thu, 18 Jul 2024 11:23:27 +0200
Subject: [PATCH] fix: max tx cost calculation for blobs

---
 bolt-sidecar/src/common.rs          | 13 +++++++++++--
 bolt-sidecar/src/state/execution.rs |  2 +-
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/bolt-sidecar/src/common.rs b/bolt-sidecar/src/common.rs
index e73c8dbd..29476f51 100644
--- a/bolt-sidecar/src/common.rs
+++ b/bolt-sidecar/src/common.rs
@@ -29,11 +29,20 @@ pub fn calculate_max_basefee(current: u128, block_diff: u64) -> Option<u128> {
 }
 
 /// Calculates the max transaction cost (gas + value) in wei.
+///
+/// - For EIP-1559 transactions: `max_fee_per_gas * gas_limit + tx_value`.
+/// - For legacy transactions: `gas_price * gas_limit + tx_value`.
+/// - For EIP-4844 blob transactions: `max_fee_per_gas * gas_limit + tx_value +
+///   max_blob_fee_per_gas * blob_gas_used`.
 pub fn max_transaction_cost(transaction: &PooledTransactionsElement) -> U256 {
     let gas_limit = transaction.gas_limit() as u128;
 
-    let fee_cap = transaction.max_fee_per_gas();
-    let fee_cap = fee_cap + transaction.max_priority_fee_per_gas().unwrap_or(0);
+    let mut fee_cap = transaction.max_fee_per_gas();
+    fee_cap += transaction.max_priority_fee_per_gas().unwrap_or(0);
+
+    if let Some(eip4844) = transaction.as_eip4844() {
+        fee_cap += eip4844.max_fee_per_blob_gas + eip4844.blob_gas() as u128;
+    }
 
     U256::from(gas_limit * fee_cap) + transaction.value()
 }
diff --git a/bolt-sidecar/src/state/execution.rs b/bolt-sidecar/src/state/execution.rs
index 6ba0b28b..60510457 100644
--- a/bolt-sidecar/src/state/execution.rs
+++ b/bolt-sidecar/src/state/execution.rs
@@ -245,7 +245,7 @@ impl<C: StateFetcher> ExecutionState<C> {
         let max_basefee = calculate_max_basefee(self.basefee, slot_diff)
             .ok_or(ValidationError::MaxBaseFeeCalcOverflow)?;
 
-        tracing::debug!(%slot_diff, %max_basefee, "Validating basefee");
+        tracing::debug!(%slot_diff, basefee = self.basefee, %max_basefee, "Validating basefee");
 
         // Validate the base fee
         if !req.validate_basefee(max_basefee) {