From 8b1d992b259869f5ca95618f32be3b75ae95cf9f Mon Sep 17 00:00:00 2001
From: Rachit Sonthalia <rachitsonthalia02@gmail.com>
Date: Mon, 4 Sep 2023 02:11:07 +0530
Subject: [PATCH] added hard fork logic for PR #1849

---
 state/executor.go       |  9 ++++-----
 state/londonFix_fork.go | 45 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+), 5 deletions(-)

diff --git a/state/executor.go b/state/executor.go
index aa2c97af0b..539ee64443 100644
--- a/state/executor.go
+++ b/state/executor.go
@@ -453,7 +453,7 @@ func (t *Transition) ContextPtr() *runtime.TxContext {
 }
 
 func (t *Transition) subGasLimitPrice(msg *types.Transaction) error {
-	upfrontGasCost := new(big.Int).Mul(new(big.Int).SetUint64(msg.Gas), msg.GetGasPrice(t.ctx.BaseFee.Uint64()))
+	upfrontGasCost := GetLondonFixHandler(uint64(t.ctx.Number)).getUpfrontGasCost(msg, t.ctx.BaseFee)
 
 	if err := t.state.SubBalance(msg.From, upfrontGasCost); err != nil {
 		if errors.Is(err, runtime.ErrNotEnoughFunds) {
@@ -600,10 +600,9 @@ func (t *Transition) apply(msg *types.Transaction) (*runtime.ExecutionResult, er
 	// Define effective tip based on tx type.
 	// We use EIP-1559 fields of the tx if the london hardfork is enabled.
 	// Effective tip became to be either gas tip cap or (gas fee cap - current base fee)
-	effectiveTip := new(big.Int).Set(gasPrice)
-	if t.config.London {
-		effectiveTip = msg.EffectiveGasTip(t.ctx.BaseFee)
-	}
+	effectiveTip := GetLondonFixHandler(uint64(t.ctx.Number)).getEffectiveTip(
+		msg, gasPrice, t.ctx.BaseFee, t.config.London,
+	)
 
 	// Pay the coinbase fee as a miner reward using the calculated effective tip.
 	coinbaseFee := new(big.Int).Mul(new(big.Int).SetUint64(result.GasUsed), effectiveTip)
diff --git a/state/londonFix_fork.go b/state/londonFix_fork.go
index 1f6772d3d3..e896a2fe39 100644
--- a/state/londonFix_fork.go
+++ b/state/londonFix_fork.go
@@ -2,8 +2,10 @@ package state
 
 import (
 	"fmt"
+	"math/big"
 
 	"github.com/0xPolygon/polygon-edge/forkmanager"
+	"github.com/0xPolygon/polygon-edge/helper/common"
 	"github.com/0xPolygon/polygon-edge/types"
 )
 
@@ -11,6 +13,9 @@ const LondonFixHandler forkmanager.HandlerDesc = "LondonFixHandler"
 
 type LondonFixFork interface {
 	checkDynamicFees(*types.Transaction, *Transition) error
+	getUpfrontGasCost(msg *types.Transaction, baseFee *big.Int) *big.Int
+	getEffectiveTip(msg *types.Transaction, gasPrice *big.Int,
+		baseFee *big.Int, isLondonForkEnabled bool) *big.Int
 }
 
 type LondonFixForkV1 struct{}
@@ -52,6 +57,33 @@ func (l *LondonFixForkV1) checkDynamicFees(msg *types.Transaction, t *Transition
 	return nil
 }
 
+func (l *LondonFixForkV1) getUpfrontGasCost(msg *types.Transaction, baseFee *big.Int) *big.Int {
+	upfrontGasCost := new(big.Int).SetUint64(msg.Gas)
+
+	factor := new(big.Int)
+	if msg.GasFeeCap != nil && msg.GasFeeCap.BitLen() > 0 {
+		// Apply EIP-1559 tx cost calculation factor
+		factor = factor.Set(msg.GasFeeCap)
+	} else {
+		// Apply legacy tx cost calculation factor
+		factor = factor.Set(msg.GasPrice)
+	}
+
+	return upfrontGasCost.Mul(upfrontGasCost, factor)
+}
+
+func (l *LondonFixForkV1) getEffectiveTip(msg *types.Transaction, gasPrice *big.Int,
+	baseFee *big.Int, isLondonForkEnabled bool) *big.Int {
+	if isLondonForkEnabled && msg.Type == types.DynamicFeeTx {
+		return common.BigMin(
+			new(big.Int).Sub(msg.GasFeeCap, baseFee),
+			new(big.Int).Set(msg.GasTipCap),
+		)
+	}
+
+	return new(big.Int).Set(gasPrice)
+}
+
 type LondonFixForkV2 struct{}
 
 func (l *LondonFixForkV2) checkDynamicFees(msg *types.Transaction, t *Transition) error {
@@ -90,6 +122,19 @@ func (l *LondonFixForkV2) checkDynamicFees(msg *types.Transaction, t *Transition
 	return nil
 }
 
+func (l *LondonFixForkV2) getUpfrontGasCost(msg *types.Transaction, baseFee *big.Int) *big.Int {
+	return new(big.Int).Mul(new(big.Int).SetUint64(msg.Gas), msg.GetGasPrice(baseFee.Uint64()))
+}
+
+func (l *LondonFixForkV2) getEffectiveTip(msg *types.Transaction, gasPrice *big.Int,
+	baseFee *big.Int, isLondonForkEnabled bool) *big.Int {
+	if isLondonForkEnabled {
+		return msg.EffectiveGasTip(baseFee)
+	}
+
+	return new(big.Int).Set(gasPrice)
+}
+
 func RegisterLondonFixFork(londonFixFork string) error {
 	fh := forkmanager.GetInstance()