From da4bd50e2c94e6f2ddb9d5c4f88bf6173b161d74 Mon Sep 17 00:00:00 2001
From: Dan Cline <6798349+Rjected@users.noreply.github.com>
Date: Wed, 20 Sep 2023 19:25:39 -0400
Subject: [PATCH 1/2] fix: add excess_blob_gas for first cancun block

---
 crates/payload/builder/src/payload.rs | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/crates/payload/builder/src/payload.rs b/crates/payload/builder/src/payload.rs
index d63d694e54ff..4ce460d5e1a1 100644
--- a/crates/payload/builder/src/payload.rs
+++ b/crates/payload/builder/src/payload.rs
@@ -177,9 +177,24 @@ impl PayloadBuilderAttributes {
         // configure evm env based on parent block
         let mut cfg = CfgEnv::default();
         cfg.chain_id = chain_spec.chain().id();
+
         // ensure we're not missing any timestamp based hardforks
         cfg.spec_id = revm_spec_by_timestamp_after_merge(chain_spec, self.timestamp);
 
+        // if the parent block did not have excess blob gas (i.e. it was pre-cancun), but it is
+        // cancun now, we need to set the excess blob gas to the default value
+        let excess_blob_gas = parent.next_block_blob_fee().map_or_else(
+            || {
+                if chain_spec.is_cancun_activated_at_timestamp(self.timestamp) {
+                    // default excess blob gas is zero
+                    Some(0)
+                } else {
+                    None
+                }
+            },
+            Some,
+        );
+
         let block_env = BlockEnv {
             number: U256::from(parent.number + 1),
             coinbase: self.suggested_fee_recipient,
@@ -192,7 +207,7 @@ impl PayloadBuilderAttributes {
                 parent.next_block_base_fee(chain_spec.base_fee_params).unwrap_or_default(),
             ),
             // calculate excess gas based on parent block's blob gas usage
-            excess_blob_gas: parent.next_block_blob_fee(),
+            excess_blob_gas,
         };
 
         (cfg, block_env)

From c0944c8b9113a506b30ab14c803e9196ca0c3f73 Mon Sep 17 00:00:00 2001
From: Dan Cline <6798349+Rjected@users.noreply.github.com>
Date: Wed, 20 Sep 2023 20:29:32 -0400
Subject: [PATCH 2/2] use SpecId to select excess_blob_gas

---
 crates/payload/builder/src/payload.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/crates/payload/builder/src/payload.rs b/crates/payload/builder/src/payload.rs
index 4ce460d5e1a1..222af177b97a 100644
--- a/crates/payload/builder/src/payload.rs
+++ b/crates/payload/builder/src/payload.rs
@@ -13,7 +13,7 @@ use reth_rpc_types_compat::engine::payload::{
     convert_block_to_payload_field_v2, convert_standalonewithdraw_to_withdrawal,
     try_block_to_payload_v1, try_block_to_payload_v3,
 };
-use revm_primitives::{BlockEnv, CfgEnv};
+use revm_primitives::{BlockEnv, CfgEnv, SpecId};
 /// Contains the built payload.
 ///
 /// According to the [engine API specification](https://github.com/ethereum/execution-apis/blob/main/src/engine/README.md) the execution layer should build the initial version of the payload with an empty transaction set and then keep update it in order to maximize the revenue.
@@ -185,7 +185,7 @@ impl PayloadBuilderAttributes {
         // cancun now, we need to set the excess blob gas to the default value
         let excess_blob_gas = parent.next_block_blob_fee().map_or_else(
             || {
-                if chain_spec.is_cancun_activated_at_timestamp(self.timestamp) {
+                if cfg.spec_id == SpecId::CANCUN {
                     // default excess blob gas is zero
                     Some(0)
                 } else {