From b09d57285ebcc9097e96470279cd02c6939dd1f4 Mon Sep 17 00:00:00 2001
From: Cal Bera <calbera@berachain.com>
Date: Wed, 18 Jun 2025 20:12:18 -0700
Subject: [PATCH] feat(BRIP-2): Gas Fee Modifications (#2)

* impl with fork-awareness

* Update protocol_params.go

* remove the change comments

* hak

* Update eip1559.go

* Update config.go

* Update protocol_params.go

* renove forkstuff

* Update genesis.go

* Update eip1559.go

* Update eip1559.go

* Update config.go

* Check for isBerachain

* feat(BRIP-2): Gas Fee Modifications

* make fork aware

* more fork aware

* more prague1 stuff

* Move all changes except EIP-1559 to prepare-fork branch

* Reset all files except EIP-1559 to match master

* fix build

* resolve conflict

* nit

* empty bera configs

* defaults

* undo unneeded changes

* undo

* Changelog

---------

Co-authored-by: Rez <rez@berachain.com>
---
 CHANGELOG.md                      |  2 ++
 consensus/misc/eip1559/eip1559.go | 19 +++++++++++++++++--
 params/config.go                  |  7 ++++++-
 3 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index dc6b4f1aa8..dba19c2d93 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,5 +16,7 @@ and this project adheres to
 
 ### Changed
 
+- BRIP-2: Allowed configuration of the `MinimumBaseFeeWei`. For Berachain, this will be set as 1 gwei. (https://github.com/berachain/bera-geth/pull/2)
+- BRIP-2: Allowed configuration of the `BaseFeeChangeDenominator`. For Berachain, this will be set as 48 (a 6x increase corresponding to 6x faster block times). (https://github.com/berachain/bera-geth/pull/2)
 - [WIP] Updated release GH workflow to publish tarballs and push built images to GHCR.
 - Removed support for appveyor, gitea, travis, circleci.
diff --git a/consensus/misc/eip1559/eip1559.go b/consensus/misc/eip1559/eip1559.go
index a90bd744b2..f6b5af915f 100644
--- a/consensus/misc/eip1559/eip1559.go
+++ b/consensus/misc/eip1559/eip1559.go
@@ -54,6 +54,21 @@ func VerifyEIP1559Header(config *params.ChainConfig, parent, header *types.Heade
 
 // CalcBaseFee calculates the basefee of the header.
 func CalcBaseFee(config *params.ChainConfig, parent *types.Header) *big.Int {
+	calculatedBaseFee := calcBaseFee(config, parent)
+
+	// Starting at the Prague1 fork, the base fee must be at least the minimum base fee.
+	if config.IsPrague1(parent.Number, parent.Time) {
+		minBaseFee := new(big.Int).SetUint64(config.Berachain.Prague1.MinimumBaseFeeWei)
+		if calculatedBaseFee.Cmp(minBaseFee) < 0 {
+			calculatedBaseFee = minBaseFee
+		}
+	}
+
+	return calculatedBaseFee
+}
+
+// calcBaseFee calculates the basefee of the header in wei.
+func calcBaseFee(config *params.ChainConfig, parent *types.Header) *big.Int {
 	// If the current block is the first EIP-1559 block, return the InitialBaseFee.
 	if !config.IsLondon(parent.Number) {
 		return new(big.Int).SetUint64(params.InitialBaseFee)
@@ -76,7 +91,7 @@ func CalcBaseFee(config *params.ChainConfig, parent *types.Header) *big.Int {
 		num.SetUint64(parent.GasUsed - parentGasTarget)
 		num.Mul(num, parent.BaseFee)
 		num.Div(num, denom.SetUint64(parentGasTarget))
-		num.Div(num, denom.SetUint64(config.BaseFeeChangeDenominator()))
+		num.Div(num, denom.SetUint64(config.BaseFeeChangeDenominator(parent.Number, parent.Time)))
 		if num.Cmp(common.Big1) < 0 {
 			return num.Add(parent.BaseFee, common.Big1)
 		}
@@ -87,7 +102,7 @@ func CalcBaseFee(config *params.ChainConfig, parent *types.Header) *big.Int {
 		num.SetUint64(parentGasTarget - parent.GasUsed)
 		num.Mul(num, parent.BaseFee)
 		num.Div(num, denom.SetUint64(parentGasTarget))
-		num.Div(num, denom.SetUint64(config.BaseFeeChangeDenominator()))
+		num.Div(num, denom.SetUint64(config.BaseFeeChangeDenominator(parent.Number, parent.Time)))
 
 		baseFee := num.Sub(parent.BaseFee, num)
 		if baseFee.Cmp(common.Big0) < 0 {
diff --git a/params/config.go b/params/config.go
index 4abf45f3de..9f80fabae3 100644
--- a/params/config.go
+++ b/params/config.go
@@ -1020,7 +1020,12 @@ func (c *ChainConfig) checkCompatible(newcfg *ChainConfig, headNumber *big.Int,
 }
 
 // BaseFeeChangeDenominator bounds the amount the base fee can change between blocks.
-func (c *ChainConfig) BaseFeeChangeDenominator() uint64 {
+func (c *ChainConfig) BaseFeeChangeDenominator(num *big.Int, time uint64) uint64 {
+	// Starting at the Prague1 fork, we use the Berachain base fee change denominator.
+	if c.IsPrague1(num, time) {
+		return c.Berachain.Prague1.BaseFeeChangeDenominator
+	}
+
 	return DefaultBaseFeeChangeDenominator
 }