ethapi, eth: implement eth_baseFee RPC method

.golangci.yml

@@ -1,7 +1,7 @@
 # This file configures github.com/golangci/golangci-lint.
 version: '2'
 run:
-  go: '1.26.3'
+  go: '1.26.4'
   tests: true
 linters:
   default: none

Dockerfile

@@ -1,5 +1,5 @@
 # ─── BUILDER STAGE ───────────────────────────────────────────────────────────────
-FROM golang:1.26.3-alpine AS builder
+FROM golang:1.26.4-alpine AS builder
 
 ARG BOR_DIR=/var/lib/bor/
 ENV BOR_DIR=$BOR_DIR

Dockerfile.alltools

@@ -1,5 +1,5 @@
 # Build Geth in a stock Go builder container
-FROM golang:1.26.3-alpine AS builder
+FROM golang:1.26.4-alpine AS builder
 
 RUN apk add --no-cache make gcc musl-dev linux-headers git
 

cmd/keeper/go.mod

@@ -1,6 +1,6 @@
 module github.com/ethereum/go-ethereum/cmd/keeper
 
-go 1.26.3
+go 1.26.4
 
 require (
 	github.com/ProjectZKM/Ziren/crates/go-runtime/zkvm_runtime v0.0.0-20260104020744-7268a54d0358

eth/api_backend.go

@@ -28,6 +28,7 @@ import (
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/ethereum/go-ethereum/consensus"
+	"github.com/ethereum/go-ethereum/consensus/misc/eip1559"
 	"github.com/ethereum/go-ethereum/consensus/misc/eip4844"
 	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/core/filtermaps"
@@ -527,9 +528,18 @@ func (b *EthAPIBackend) FeeHistory(ctx context.Context, blockCount uint64, lastB
 	return b.gpo.FeeHistory(ctx, blockCount, lastBlock, rewardPercentiles)
 }
 
+func (b *EthAPIBackend) BaseFee(ctx context.Context) *big.Int {
+	header := b.CurrentHeader()
+	if b.ChainConfig().IsLondon(new(big.Int).Add(header.Number, common.Big1)) {
+		return eip1559.CalcBaseFee(b.ChainConfig(), header)
+	}
+	return nil
+}
+
 func (b *EthAPIBackend) BlobBaseFee(ctx context.Context) *big.Int {
-	if excess := b.CurrentHeader().ExcessBlobGas; excess != nil && b.ChainConfig().BlobScheduleConfig != nil {
-		return eip4844.CalcBlobFee(b.ChainConfig(), b.CurrentHeader())
+	header := b.CurrentHeader()
+	if header.ExcessBlobGas != nil && b.ChainConfig().BlobScheduleConfig != nil {
+		return eip4844.CalcBlobFee(b.ChainConfig(), header)
 	}
 	return nil
 }

eth/api_backend_test.go

@@ -349,6 +349,116 @@ func TestRelayMethodWiring(t *testing.T) {
 	})
 }
 
+func TestBaseFee(t *testing.T) {
+	t.Run("LondonActive", func(t *testing.T) {
+		b := initBackend(false)
+		defer b.eth.blockchain.Stop()
+		if b.BaseFee(t.Context()) == nil {
+			t.Fatal("expected non-nil BaseFee when London is active")
+		}
+	})
+
+	t.Run("LondonTransitionBlock", func(t *testing.T) {
+		// LondonBlock = 1 so the genesis block (number 0) is the pre-London
+		// parent of the first London block. IsLondon(0) is false, but
+		// IsLondon(0+1) is true, so BaseFee must return InitialBaseFee.
+		config := *params.NonActivatedConfig
+		config.HomesteadBlock = big.NewInt(0)
+		config.EIP150Block = big.NewInt(0)
+		config.EIP155Block = big.NewInt(0)
+		config.EIP158Block = big.NewInt(0)
+		config.ByzantiumBlock = big.NewInt(0)
+		config.ConstantinopleBlock = big.NewInt(0)
+		config.PetersburgBlock = big.NewInt(0)
+		config.IstanbulBlock = big.NewInt(0)
+		config.BerlinBlock = big.NewInt(0)
+		config.LondonBlock = big.NewInt(1)
+		db := rawdb.NewMemoryDatabase()
+		genesis := &core.Genesis{
+			Config:     &config,
+			Difficulty: big.NewInt(1),
+		}
+		chain, err := core.NewBlockChain(db, genesis, ethash.NewFaker(), nil)
+		require.NoError(t, err)
+		defer chain.Stop()
+		b := &EthAPIBackend{eth: &Ethereum{blockchain: chain}}
+		got := b.BaseFee(t.Context())
+		if got == nil {
+			t.Fatal("expected InitialBaseFee at London transition block, got nil")
+		}
+		expected := new(big.Int).SetUint64(params.InitialBaseFee)
+		if got.Cmp(expected) != 0 {
+			t.Fatalf("expected BaseFee %v, got %v", expected, got)
+		}
+	})
+
+	t.Run("PreLondon", func(t *testing.T) {
+		// NonActivatedConfig has no LondonBlock — IsLondon always returns false.
+		db := rawdb.NewMemoryDatabase()
+		genesis := &core.Genesis{
+			Config:     params.NonActivatedConfig,
+			Difficulty: big.NewInt(1),
+		}
+		chain, err := core.NewBlockChain(db, genesis, ethash.NewFaker(), nil)
+		require.NoError(t, err)
+		defer chain.Stop()
+		b := &EthAPIBackend{eth: &Ethereum{blockchain: chain}}
+		if b.BaseFee(t.Context()) != nil {
+			t.Fatal("expected nil BaseFee when London is inactive")
+		}
+	})
+}
+
+func TestBlobBaseFee(t *testing.T) {
+	t.Run("CancunActive", func(t *testing.T) {
+		// MergedTestChainConfig has Cancun at block 0 with a BlobScheduleConfig.
+		// Genesis sets ExcessBlobGas = new(uint64) so the guard passes.
+		b := initBackend(false)
+		defer b.eth.blockchain.Stop()
+		if b.BlobBaseFee(t.Context()) == nil {
+			t.Fatal("expected non-nil BlobBaseFee when Cancun is active")
+		}
+	})
+
+	t.Run("NoExcessBlobGas", func(t *testing.T) {
+		// AllEthashProtocolChanges has London at block 0 but no CancunBlock.
+		// Genesis therefore leaves ExcessBlobGas nil, so BlobBaseFee must return nil.
+		db := rawdb.NewMemoryDatabase()
+		genesis := &core.Genesis{
+			Config:     params.AllEthashProtocolChanges,
+			BaseFee:    big.NewInt(params.InitialBaseFee),
+			Difficulty: big.NewInt(1),
+		}
+		chain, err := core.NewBlockChain(db, genesis, ethash.NewFaker(), nil)
+		require.NoError(t, err)
+		defer chain.Stop()
+		b := &EthAPIBackend{eth: &Ethereum{blockchain: chain}}
+		if b.BlobBaseFee(t.Context()) != nil {
+			t.Fatal("expected nil BlobBaseFee when ExcessBlobGas is nil")
+		}
+	})
+
+	t.Run("NoBlobScheduleConfig", func(t *testing.T) {
+		// Cancun active but BlobScheduleConfig nil: ExcessBlobGas is set by genesis
+		// (not nil), but the guard short-circuits before calling CalcBlobFee.
+		db := rawdb.NewMemoryDatabase()
+		config := *params.MergedTestChainConfig
+		config.BlobScheduleConfig = nil
+		genesis := &core.Genesis{
+			Config:     &config,
+			Difficulty: common.Big0,
+			BaseFee:    big.NewInt(params.InitialBaseFee),
+		}
+		chain, err := core.NewBlockChain(db, genesis, beacon.New(ethash.NewFaker()), nil)
+		require.NoError(t, err)
+		defer chain.Stop()
+		b := &EthAPIBackend{eth: &Ethereum{blockchain: chain}}
+		if b.BlobBaseFee(t.Context()) != nil {
+			t.Fatal("expected nil BlobBaseFee when BlobScheduleConfig is nil")
+		}
+	})
+}
+
 // TestRelayGracefulShutdownOnStop verifies that the relay shutdown path in
 // Ethereum.Stop() completes promptly and doesn't hang or panic.
 func TestRelayGracefulShutdownOnStop(t *testing.T) {

go.mod

@@ -1,7 +1,7 @@
 module github.com/ethereum/go-ethereum
 
 // Note: Change the go image version in Dockerfile if you change this.
-go 1.26.3
+go 1.26.4
 
 require (
 	github.com/0xPolygon/crand v1.0.3

internal/ethapi/api.go

@@ -213,6 +213,11 @@ func (api *EthereumAPI) BlobBaseFee(ctx context.Context) *hexutil.Big {
 	return (*hexutil.Big)(api.b.BlobBaseFee(ctx))
 }
 
+// BaseFee returns the base fee of the next block.
+func (api *EthereumAPI) BaseFee(ctx context.Context) *hexutil.Big {
+	return (*hexutil.Big)(api.b.BaseFee(ctx))
+}
+
 // Syncing returns false in case the node is currently not syncing with the network. It can be up-to-date or has not
 // yet received the latest block headers from its peers. In case it is synchronizing:
 // - startingBlock: block number this node started to synchronize from

internal/ethapi/api_test.go

@@ -546,6 +546,7 @@ func (b testBackend) FeeHistory(ctx context.Context, blockCount uint64, lastBloc
 	return nil, nil, nil, nil, nil, nil, nil
 }
 func (b testBackend) BlobBaseFee(ctx context.Context) *big.Int { return new(big.Int) }
+func (b testBackend) BaseFee(ctx context.Context) *big.Int     { return new(big.Int) }
 func (b testBackend) ChainDb() ethdb.Database                  { return b.db }
 func (b testBackend) AccountManager() *accounts.Manager        { return b.accman }
 func (b testBackend) ExtRPCEnabled() bool                      { return false }

internal/ethapi/backend.go

@@ -52,6 +52,7 @@ type Backend interface {
 	SuggestGasTipCap(ctx context.Context) (*big.Int, error)
 	FeeHistory(ctx context.Context, blockCount uint64, lastBlock rpc.BlockNumber, rewardPercentiles []float64) (*big.Int, [][]*big.Int, []*big.Int, []float64, []*big.Int, []float64, error)
 	BlobBaseFee(ctx context.Context) *big.Int
+	BaseFee(ctx context.Context) *big.Int
 	ChainDb() ethdb.Database
 	AccountManager() *accounts.Manager
 	ExtRPCEnabled() bool

internal/ethapi/transaction_args_test.go

@@ -333,6 +333,7 @@ func (b *backendMock) SuggestGasTipCap(ctx context.Context) (*big.Int, error) {
 	return big.NewInt(42), nil
 }
 func (b *backendMock) BlobBaseFee(ctx context.Context) *big.Int { return big.NewInt(42) }
+func (b *backendMock) BaseFee(ctx context.Context) *big.Int     { return big.NewInt(0) }
 
 func (b *backendMock) CurrentHeader() *types.Header     { return b.current }
 func (b *backendMock) ChainConfig() *params.ChainConfig { return b.config }