From a1b6b2229ad2205ed565c6f651606536f2a6985f Mon Sep 17 00:00:00 2001
From: Moon Shiesty <moonshiesty@protonmail.com>
Date: Thu, 30 Nov 2023 14:12:45 -0600
Subject: [PATCH] Support base fee vault (#13)

---
 core/state_transition.go | 6 ++++++
 params/config.go         | 4 +++-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/core/state_transition.go b/core/state_transition.go
index d31a2975b0..1dc0fb8e55 100644
--- a/core/state_transition.go
+++ b/core/state_transition.go
@@ -506,6 +506,12 @@ func (st *StateTransition) TransitionDb() (*ExecutionResult, error) {
 		st.state.AddBalance(st.evm.Context.Coinbase, fee)
 	}
 
+	// <specular modification>
+	if (st.evm.ChainConfig().L2BaseFeeRecipient != common.Address{}) {
+		st.state.AddBalance(st.evm.ChainConfig().L2BaseFeeRecipient, new(big.Int).Mul(new(big.Int).SetUint64(st.gasUsed()), st.evm.Context.BaseFee))
+	}
+	// </specular modification>
+
 	return &ExecutionResult{
 		UsedGas:    st.gasUsed(),
 		Err:        vmerr,
diff --git a/params/config.go b/params/config.go
index 55df8579d6..2cc45eae3e 100644
--- a/params/config.go
+++ b/params/config.go
@@ -335,7 +335,8 @@ type ChainConfig struct {
 	IsDevMode bool          `json:"isDev,omitempty"`
 
 	// <specular modification>
-	EnableL2EngineApi bool `json:"enableL2EngineApi,omitempty"`
+	EnableL2EngineApi  bool           `json:"enableL2EngineApi,omitempty"`
+	L2BaseFeeRecipient common.Address `json:"l2BaseFeeRecipient,omitempty"`
 	// <specular modification/>
 }
 
@@ -372,6 +373,7 @@ func (c *ChainConfig) Description() string {
 	// <specular modification>
 	case c.EnableL2EngineApi:
 		banner += "Consensus: L2 gas limit API enabled\n"
+		banner += fmt.Sprintf(" - L2 Base fee recipient: %s\n", c.L2BaseFeeRecipient)
 	// <specular modification/>
 	case c.Ethash != nil:
 		if c.TerminalTotalDifficulty == nil {