Reinstate l1cost function for alfajores (#271)

This commit reinstates a custom l1 cost function for Alfajores which always
returns zero.

We thought we could get rid of this by simply setting the l1 fee scalars to
zero, but we missed the l1 blob fee scalars on alfajores so removing our custom
l1 cost function causes a hardfork while syncing alfajores.

In order to remove our l1 cost function without introducing an unintentional
hardfork, we'll need to have a hardfork so that we can switch off the use of
the cost function at a certain point. But for now reinstating our custom cost
function means that we can use this branch for our alfajores deployment. This
saves us having to manage two separate branches (one for local development
and one to be deployed on alfajores).

compat_test/compat_test.go

@@ -19,6 +19,7 @@ import (
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/ethclient"
+	"github.com/ethereum/go-ethereum/params"
 	"github.com/ethereum/go-ethereum/rlp"
 	"github.com/ethereum/go-ethereum/rpc"
 	"github.com/stretchr/testify/require"
@@ -40,7 +41,7 @@ var (
 	celoRpcURL        string
 	opGethRpcURL      string
 	startBlock        uint64
-	gingerbreadBlocks = map[uint64]uint64{42220: 21616000, 62320: 18785000, 44787: 19814000}
+	gingerbreadBlocks = map[uint64]uint64{params.CeloMainnetChainID: 21616000, params.CeloBaklavaChainID: 18785000, params.CeloAlfajoresChainID: 19814000}
 )
 
 func init() {

contracts/addresses/addresses.go

@@ -12,7 +12,4 @@ var (
 
 	CeloTokenBaklavaAddress  = common.HexToAddress("0xdDc9bE57f553fe75752D61606B94CBD7e0264eF8")
 	FeeHandlerBaklavaAddress = common.HexToAddress("0xeed0A69c51079114C280f7b936C79e24bD94013e")
-
-	AlfajoresChainID uint64 = 44787
-	BaklavaChainID   uint64 = 62320
 )

core/state_transition.go

@@ -766,10 +766,10 @@ func (st *StateTransition) distributeTxFees() error {
 
 	feeCurrency := st.msg.FeeCurrency
 	feeHandlerAddress := addresses.FeeHandlerAddress
-	if st.evm.ChainConfig().ChainID != nil && st.evm.ChainConfig().ChainID.Uint64() == addresses.AlfajoresChainID {
+	if st.evm.ChainConfig().ChainID != nil && st.evm.ChainConfig().ChainID.Uint64() == params.CeloAlfajoresChainID {
 		feeHandlerAddress = addresses.FeeHandlerAlfajoresAddress
 	}
-	if st.evm.ChainConfig().ChainID != nil && st.evm.ChainConfig().ChainID.Uint64() == addresses.BaklavaChainID {
+	if st.evm.ChainConfig().ChainID != nil && st.evm.ChainConfig().ChainID.Uint64() == params.CeloBaklavaChainID {
 		feeHandlerAddress = addresses.FeeHandlerBaklavaAddress
 	}
 

core/types/rollup_cost.go

@@ -124,6 +124,11 @@ func NewL1CostFunc(config *params.ChainConfig, statedb StateGetter) L1CostFunc {
 	forBlock := ^uint64(0)
 	var cachedFunc l1CostFunc
 	selectFunc := func(blockTime uint64) l1CostFunc {
+		// Alfajores requires a custom cost function see link for a detailed explanation
+		// https://github.com/celo-org/op-geth/pull/271
+		if config.IsCel2(blockTime) && config.ChainID.Uint64() == params.CeloAlfajoresChainID {
+			return func(rcd RollupCostData) (fee, gasUsed *big.Int) { return new(big.Int), new(big.Int) }
+		}
 		if !config.IsOptimismEcotone(blockTime) {
 			return newL1CostFuncBedrock(config, statedb, blockTime)
 		}

core/vm/celo_contracts.go

@@ -48,10 +48,10 @@ func celoPrecompileAddress(index byte) common.Address {
 
 func (ctx *celoPrecompileContext) IsCallerCeloToken() (bool, error) {
 	tokenAddress := addresses.CeloTokenAddress
-	if ctx.evm.ChainConfig().ChainID != nil && ctx.evm.ChainConfig().ChainID.Uint64() == addresses.AlfajoresChainID {
+	if ctx.evm.ChainConfig().ChainID != nil && ctx.evm.ChainConfig().ChainID.Uint64() == params.CeloAlfajoresChainID {
 		tokenAddress = addresses.CeloTokenAlfajoresAddress
 	}
-	if ctx.evm.ChainConfig().ChainID != nil && ctx.evm.ChainConfig().ChainID.Uint64() == addresses.BaklavaChainID {
+	if ctx.evm.ChainConfig().ChainID != nil && ctx.evm.ChainConfig().ChainID.Uint64() == params.CeloBaklavaChainID {
 		tokenAddress = addresses.CeloTokenBaklavaAddress
 	}
 

internal/ethapi/celo_api_test.go

@@ -405,7 +405,7 @@ func TestNewRPCTransactionDynamicFee(t *testing.T) {
 func allEnabledChainConfig() *params.ChainConfig {
 	zeroTime := uint64(0)
 	return &params.ChainConfig{
-		ChainID:             big.NewInt(44787),
+		ChainID:             big.NewInt(params.CeloAlfajoresChainID),
 		HomesteadBlock:      big.NewInt(0),
 		EIP150Block:         big.NewInt(0),
 		EIP155Block:         big.NewInt(0),

params/config.go

@@ -36,6 +36,8 @@ const (
 	OPMainnetChainID        = 10
 	OPGoerliChainID         = 420
 	CeloMainnetChainID      = 42220
+	CeloBaklavaChainID      = 62320
+	CeloAlfajoresChainID    = 44787
 	BaseMainnetChainID      = 8453
 	BaseGoerliChainID       = 84531
 	baseSepoliaChainID      = 84532