refactor(ethclient): implement new sim backend #28202 (#2062)

Introduce a new simulated backend implementation under ethclient/simulated and migrate bind-facing wrappers/tests to use it.

Key changes:

- Add the new backend entry points and behavior in ethclient/simulated, including chain control helpers used by tests (commit/rollback/fork/time adjustment).

- Update legacy bind wrappers in accounts/abi/bind/backends to delegate to the new simulated backend while preserving old APIs.

- Align bind v2/backend and utility tests to the new simulated backend client surface and transaction flow.

- Refresh abigen/bind tests and shared interfaces impacted by the backend migration.

Compatibility notes:

- Keep backward-compatible wrapper constructors for existing contract test code.

- Preserve legacy transaction paths in tests while supporting EIP-1559-aware flows where applicable.

Validation:

- Verified affected packages compile and pass tests.

- Verified repository-wide go test ./... passes after follow-up compatibility fixes.

accounts/abi/abigen/bind_test.go

@@ -306,6 +306,7 @@ var bindTests = []struct {
 			if err != nil {
 				t.Fatalf("Failed to deploy interactor contract: %v", err)
 			}
+			sim.Commit()
 			if _, err := interactor.Transact(auth, "Transact string"); err != nil {
 				t.Fatalf("Failed to transact with interactor contract: %v", err)
 			}
@@ -519,6 +520,7 @@ var bindTests = []struct {
 			if err != nil {
 				t.Fatalf("Failed to deploy defaulter contract: %v", err)
 			}
+			sim.Commit()
 			if _, err := (&DefaulterRaw{defaulter}).Transfer(auth); err != nil {
 				t.Fatalf("Failed to invoke default method: %v", err)
 			}
@@ -1842,6 +1844,7 @@ var bindTests = []struct {
 		[]string{"0x6080604052348015600f57600080fd5b5060998061001e6000396000f3fe6080604052348015600f57600080fd5b506004361060285760003560e01c8063726c638214602d575b600080fd5b60336035565b005b60405163024876cd60e61b815260016004820152600260248201526003604482015260640160405180910390fdfea264697066735822122093f786a1bc60216540cd999fbb4a6109e0fef20abcff6e9107fb2817ca968f3c64736f6c63430008070033"},
 		[]string{`[{"inputs":[{"internalType":"uint256","name":"","type":"uint256"}],"name":"MyError","type":"error"},{"inputs":[{"internalType":"uint256","name":"","type":"uint256"}],"name":"MyError1","type":"error"},{"inputs":[{"internalType":"uint256","name":"","type":"uint256"},{"internalType":"uint256","name":"","type":"uint256"}],"name":"MyError2","type":"error"},{"inputs":[{"internalType":"uint256","name":"a","type":"uint256"},{"internalType":"uint256","name":"b","type":"uint256"},{"internalType":"uint256","name":"c","type":"uint256"}],"name":"MyError3","type":"error"},{"inputs":[],"name":"Error","outputs":[],"stateMutability":"pure","type":"function"}]`},
 		`
+			"context"
 			"math/big"
 
 			"github.com/XinFinOrg/XDPoSChain/accounts/abi/bind"
@@ -1863,7 +1866,7 @@ var bindTests = []struct {
 				t.Fatal(err)
 			}
 			sim.Commit()
-			_, err = bind.WaitDeployed(nil, sim, tx)
+			_, err = bind.WaitDeployed(context.Background(), sim, tx)
 			if err != nil {
 				t.Error(err)
 			}
@@ -1894,6 +1897,7 @@ var bindTests = []struct {
 		bytecode: []string{`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`},
 		abi:      []string{`[{"inputs":[{"components":[{"internalType":"uint256","name":"field","type":"uint256"}],"internalType":"struct ConstructorWithStructParam.StructType","name":"st","type":"tuple"}],"stateMutability":"nonpayable","type":"constructor"}]`},
 		imports: `
+			"context"
 			"math/big"
 
 			"github.com/XinFinOrg/XDPoSChain/accounts/abi/bind"
@@ -1916,7 +1920,7 @@ var bindTests = []struct {
 			}
 			sim.Commit()
 
-			if _, err = bind.WaitDeployed(nil, sim, tx); err != nil {
+			if _, err = bind.WaitDeployed(context.Background(), sim, tx); err != nil {
 				t.Logf("Deployment tx: %+v", tx)
 				t.Errorf("bind.WaitDeployed(nil, %T, <deployment tx>) got err %v; want nil err", sim, err)
 			}
@@ -1983,6 +1987,7 @@ var bindTests = []struct {
 		bytecode: []string{"0x608060405234801561001057600080fd5b5060dc8061001f6000396000f3fe6080604052348015600f57600080fd5b506004361060285760003560e01c8063527a119f14602d575b600080fd5b60436004803603810190603f9190605b565b6045565b005b50565b6000813590506055816092565b92915050565b600060208284031215606e57606d608d565b5b6000607a848285016048565b91505092915050565b6000819050919050565b600080fd5b6099816083565b811460a357600080fd5b5056fea2646970667358221220d4f4525e2615516394055d369fb17df41c359e5e962734f27fd683ea81fd9db164736f6c63430008070033"},
 		abi:      []string{`[{"inputs":[{"internalType":"uint256","name":"range","type":"uint256"}],"name":"functionWithKeywordParameter","outputs":[],"stateMutability":"pure","type":"function"}]`},
 		imports: `
+			"context"
 			"math/big"
 
 			"github.com/XinFinOrg/XDPoSChain/accounts/abi/bind"
@@ -2003,7 +2008,7 @@ var bindTests = []struct {
 			}
 			sim.Commit()
 
-			if _, err = bind.WaitDeployed(nil, sim, tx); err != nil {
+			if _, err = bind.WaitDeployed(context.Background(), sim, tx); err != nil {
 				t.Errorf("error deploying the contract: %v", err)
 			}
 		`,

accounts/abi/bind/v2/backend.go

@@ -89,6 +89,11 @@ type BlockHashContractCaller interface {
 // used when the user does not provide some needed values, but rather leaves it up
 // to the transactor to decide.
 type ContractTransactor interface {
+	ethereum.GasEstimator
+	ethereum.GasPricer
+	ethereum.GasPricer1559
+	ethereum.TransactionSender
+
 	// HeaderByNumber returns a block header from the current canonical chain. If
 	// number is nil, the latest known header is returned.
 	HeaderByNumber(ctx context.Context, number *big.Int) (*types.Header, error)
@@ -98,38 +103,6 @@ type ContractTransactor interface {
 
 	// PendingNonceAt retrieves the current pending nonce associated with an account.
 	PendingNonceAt(ctx context.Context, account common.Address) (uint64, error)
-
-	// SuggestGasPrice retrieves the currently suggested gas price to allow a timely
-	// execution of a transaction.
-	SuggestGasPrice(ctx context.Context) (*big.Int, error)
-
-	// SuggestGasTipCap retrieves the currently suggested 1559 priority fee to allow
-	// a timely execution of a transaction.
-	SuggestGasTipCap(ctx context.Context) (*big.Int, error)
-
-	// EstimateGas tries to estimate the gas needed to execute a specific
-	// transaction based on the current pending state of the backend blockchain.
-	// There is no guarantee that this is the true gas limit requirement as other
-	// transactions may be added or removed by miners, but it should provide a basis
-	// for setting a reasonable default.
-	EstimateGas(ctx context.Context, call ethereum.CallMsg) (gas uint64, err error)
-
-	// SendTransaction injects the transaction into the pending pool for execution.
-	SendTransaction(ctx context.Context, tx *types.Transaction) error
-}
-
-// ContractFilterer defines the methods needed to access log events using one-off
-// queries or continuous event subscriptions.
-type ContractFilterer interface {
-	// FilterLogs executes a log filter operation, blocking during execution and
-	// returning all the results in one batch.
-	//
-	// TODO(karalabe): Deprecate when the subscription one can return past data too.
-	FilterLogs(ctx context.Context, query ethereum.FilterQuery) ([]types.Log, error)
-
-	// SubscribeFilterLogs creates a background log filtering operation, returning
-	// a subscription immediately, which can be used to stream the found events.
-	SubscribeFilterLogs(ctx context.Context, query ethereum.FilterQuery, ch chan<- types.Log) (ethereum.Subscription, error)
 }
 
 // DeployBackend wraps the operations needed by WaitMined and WaitDeployed.
@@ -138,6 +111,12 @@ type DeployBackend interface {
 	CodeAt(ctx context.Context, account common.Address, blockNumber *big.Int) ([]byte, error)
 }
 
+// ContractFilterer defines the methods needed to access log events using one-off
+// queries or continuous event subscriptions.
+type ContractFilterer interface {
+	ethereum.LogFilterer
+}
+
 // ContractBackend defines the methods needed to work with contracts on a read-write basis.
 type ContractBackend interface {
 	ContractCaller

accounts/abi/bind/v2/util_test.go

@@ -28,6 +28,7 @@ import (
 	"github.com/XinFinOrg/XDPoSChain/common"
 	"github.com/XinFinOrg/XDPoSChain/core/types"
 	"github.com/XinFinOrg/XDPoSChain/crypto"
+	"github.com/XinFinOrg/XDPoSChain/ethclient/simulated"
 	"github.com/XinFinOrg/XDPoSChain/params"
 )
 
@@ -57,7 +58,7 @@ func TestWaitDeployed(t *testing.T) {
 	config := *params.TestXDPoSMockChainConfig
 	config.Eip1559Block = big.NewInt(0)
 	for name, test := range waitDeployedTests {
-		backend := backends.NewXDCSimulatedBackend(
+		backend := simulated.New(
 			types.GenesisAlloc{
 				crypto.PubkeyToAddress(testKey.PublicKey): {Balance: big.NewInt(100000000000000000)},
 			},
@@ -67,7 +68,7 @@ func TestWaitDeployed(t *testing.T) {
 		defer backend.Close()
 
 		// Create the transaction
-		head, _ := backend.HeaderByNumber(context.Background(), nil) // Should be child's, good enough
+		head, _ := backend.Client().HeaderByNumber(context.Background(), nil) // Should be child's, good enough
 		gasPrice := new(big.Int).Add(head.BaseFee, big.NewInt(1))
 
 		tx := types.NewContractCreation(0, big.NewInt(0), test.gas, gasPrice, common.FromHex(test.code))
@@ -81,12 +82,12 @@ func TestWaitDeployed(t *testing.T) {
 			ctx     = context.Background()
 		)
 		go func() {
-			address, err = bind.WaitDeployed(ctx, backend, tx.Hash())
+			address, err = bind.WaitDeployed(ctx, backend.Client(), tx.Hash())
 			close(mined)
 		}()
 
 		// Send and mine the transaction.
-		if err := backend.SendTransaction(ctx, tx); err != nil {
+		if err := backend.Client().SendTransaction(ctx, tx); err != nil {
 			t.Errorf("test %q: failed to send transaction: %v", name, err)
 		}
 		backend.Commit()
@@ -116,7 +117,7 @@ func TestWaitDeployedCornerCases(t *testing.T) {
 			10000000,
 			&config,
 		)
-		head, _     = backend.HeaderByNumber(context.Background(), nil) // Should be child's, good enough
+		head, _     = backend.Client().HeaderByNumber(context.Background(), nil) // Should be child's, good enough
 		gasPrice    = new(big.Int).Add(head.BaseFee, big.NewInt(1))
 		signer      = types.LatestSigner(&config)
 		code        = common.FromHex("6060604052600a8060106000396000f360606040526008565b00")
@@ -133,11 +134,11 @@ func TestWaitDeployedCornerCases(t *testing.T) {
 		GasPrice: gasPrice,
 		Data:     code,
 	})
-	if err := backend.SendTransaction(ctx, tx); err != nil {
+	if err := backend.Client().SendTransaction(ctx, tx); err != nil {
 		t.Errorf("failed to send transaction: %q", err)
 	}
 	backend.Commit()
-	if _, err := bind.WaitDeployed(ctx, backend, tx.Hash()); err != bind.ErrNoAddressInReceipt {
+	if _, err := bind.WaitDeployed(ctx, backend.Client(), tx.Hash()); err != bind.ErrNoAddressInReceipt {
 		t.Errorf("error mismatch: want %q, got %q, ", bind.ErrNoAddressInReceipt, err)
 	}
 
@@ -154,13 +155,13 @@ func TestWaitDeployedCornerCases(t *testing.T) {
 	done := make(chan struct{})
 	go func() {
 		defer close(done)
-		_, err := bind.WaitDeployed(ctx, backend, tx.Hash())
+		_, err := bind.WaitDeployed(ctx, backend.Client(), tx.Hash())
 		if !errors.Is(err, context.Canceled) {
 			t.Errorf("error mismatch: want %v, got %v", context.Canceled, err)
 		}
 	}()
 
-	if err := backend.SendTransaction(ctx, tx); err != nil {
+	if err := backend.Client().SendTransaction(ctx, tx); err != nil {
 		t.Errorf("failed to send transaction: %q", err)
 	}
 	cancel()

interfaces.go

@@ -186,6 +186,16 @@ type GasPricer interface {
 	SuggestGasPrice(ctx context.Context) (*big.Int, error)
 }
 
+// GasPricer1559 provides access to the EIP-1559 gas price oracle.
+type GasPricer1559 interface {
+	SuggestGasTipCap(ctx context.Context) (*big.Int, error)
+}
+
+// FeeHistoryReader provides access to the fee history oracle.
+type FeeHistoryReader interface {
+	FeeHistory(ctx context.Context, blockCount uint64, lastBlock *big.Int, rewardPercentiles []float64) (*FeeHistory, error)
+}
+
 // FeeHistory provides recent fee market data that consumers can use to determine
 // a reasonable maxPriorityFeePerGas value.
 type FeeHistory struct {
@@ -227,6 +237,16 @@ type PendingStateEventer interface {
 	SubscribePendingTransactions(ctx context.Context, ch chan<- *types.Transaction) (Subscription, error)
 }
 
+// BlockNumberReader provides access to the current block number.
+type BlockNumberReader interface {
+	BlockNumber(ctx context.Context) (uint64, error)
+}
+
+// ChainIDReader provides access to the chain ID.
+type ChainIDReader interface {
+	ChainID(ctx context.Context) (*big.Int, error)
+}
+
 // OverrideAccount specifies the state of an account to be overridden.
 type OverrideAccount struct {
 	// Nonce sets nonce of the account. Note: the nonce override will only