estimateGas fix for simple value transactions and contract creations (

#1998)

e2e-polybft/e2e/jsonrpc_test.go

@@ -13,6 +13,7 @@ import (
 	"github.com/0xPolygon/polygon-edge/consensus/polybft/contractsapi"
 	"github.com/0xPolygon/polygon-edge/e2e-polybft/framework"
 	"github.com/0xPolygon/polygon-edge/helper/hex"
+	"github.com/0xPolygon/polygon-edge/state"
 	"github.com/0xPolygon/polygon-edge/types"
 )
 
@@ -126,6 +127,40 @@ func TestE2E_JsonRPC(t *testing.T) {
 		require.Equal(t, uint64(0x56a3), resp)
 	})
 
+	t.Run("eth_estimateGas by zero-balance account - simple value transfer", func(t *testing.T) {
+		acctZeroBalance, err := wallet.GenerateKey()
+		require.NoError(t, err)
+
+		fundedAccountAddress := acct.Address()
+		nonFundedAccountAddress := acctZeroBalance.Address()
+
+		estimateGasFn := func(value *big.Int) {
+			resp, err := client.EstimateGas(&ethgo.CallMsg{
+				From:  nonFundedAccountAddress,
+				To:    &fundedAccountAddress,
+				Value: value,
+			})
+
+			require.NoError(t, err)
+			require.Equal(t, state.TxGas, resp)
+		}
+
+		estimateGasFn(ethgo.Gwei(1))
+
+		// transfer some funds to zero balance account
+		valueTransferTxn := cluster.SendTxn(t, acct, &ethgo.Transaction{
+			From:  fundedAccountAddress,
+			To:    &nonFundedAccountAddress,
+			Value: ethgo.Gwei(10),
+		})
+
+		require.NoError(t, valueTransferTxn.Wait())
+		require.True(t, valueTransferTxn.Succeed())
+
+		// now call estimate gas again for the now funded account
+		estimateGasFn(ethgo.Gwei(1))
+	})
+
 	t.Run("eth_getBalance", func(t *testing.T) {
 		key1, err := wallet.GenerateKey()
 		require.NoError(t, err)

jsonrpc/eth_endpoint.go

@@ -551,13 +551,24 @@ func (e *Eth) EstimateGas(arg *txnArgs, rawNum *BlockNumber) (interface{}, error
 		return nil, err
 	}
 
+	forksInTime := e.store.GetForksInTime(header.Number)
+
+	if transaction.IsValueTransfer() {
+		// if it is a simple value transfer or a contract creation,
+		// we already know what is the transaction gas cost, no need to apply transaction
+		gasCost, err := state.TransactionGasCost(transaction, forksInTime.Homestead, forksInTime.Istanbul)
+		if err != nil {
+			return nil, err
+		}
+
+		return argUint64(gasCost), nil
+	}
+
 	// Force transaction gas price if empty
 	if err = e.fillTransactionGasPrice(transaction); err != nil {
 		return nil, err
 	}
 
-	forksInTime := e.store.GetForksInTime(header.Number)
-
 	var standardGas uint64
 	if transaction.IsContractCreation() && forksInTime.Homestead {
 		standardGas = state.TxGasContractCreation
@@ -579,7 +590,6 @@ func (e *Eth) EstimateGas(arg *txnArgs, rawNum *BlockNumber) (interface{}, error
 	}
 
 	gasPriceInt := new(big.Int).Set(transaction.GasPrice)
-	valueInt := new(big.Int).Set(transaction.Value)
 
 	var availableBalance *big.Int
 
@@ -602,14 +612,6 @@ func (e *Eth) EstimateGas(arg *txnArgs, rawNum *BlockNumber) (interface{}, error
 		}
 
 		availableBalance = new(big.Int).Set(accountBalance)
-
-		if transaction.Value != nil {
-			if valueInt.Cmp(availableBalance) > 0 {
-				return 0, ErrInsufficientFunds
-			}
-
-			availableBalance.Sub(availableBalance, valueInt)
-		}
 	}
 
 	// Recalculate the gas ceiling based on the available funds (if any)
@@ -663,7 +665,7 @@ func (e *Eth) EstimateGas(arg *txnArgs, rawNum *BlockNumber) (interface{}, error
 
 		transaction.Gas = gas
 
-		result, applyErr := e.store.ApplyTxn(header, transaction, nil, false)
+		result, applyErr := e.store.ApplyTxn(header, transaction, nil, true)
 
 		if result != nil {
 			data = []byte(hex.EncodeToString(result.ReturnValue))

jsonrpc/eth_state_test.go

@@ -772,27 +772,59 @@ func TestEth_EstimateGas_Reverts(t *testing.T) {
 	}
 }
 
-func TestEth_EstimateGas_Errors(t *testing.T) {
+func TestEth_EstimateGas_ValueTransfer(t *testing.T) {
 	store := getExampleStore()
 	ethEndpoint := newTestEthEndpoint(store)
 
 	// Account doesn't have any balance
 	store.account.account.Balance = big.NewInt(0)
 
 	// The transaction has a value > 0
+	from := types.StringToAddress("0xSenderAddress")
+	to := types.StringToAddress("0xReceiverAddress")
 	mockTx := constructMockTx(nil, nil)
 	mockTx.Value = argBytesPtr([]byte{0x1})
+	mockTx.From = &from
+	mockTx.To = &to
 
 	// Run the estimation
-	estimate, estimateErr := ethEndpoint.EstimateGas(
+	estimate, err := ethEndpoint.EstimateGas(
 		mockTx,
 		nil,
 	)
 
-	assert.Equal(t, 0, estimate)
+	assert.NotNil(t, estimate)
+	estimateUint64, ok := estimate.(argUint64)
+	assert.True(t, ok)
+	assert.NoError(t, err)
+	assert.Equal(t, state.TxGas, uint64(estimateUint64)) // simple value transfers are 21000wei always
+}
+
+func TestEth_EstimateGas_ContractCreation(t *testing.T) {
+	store := getExampleStore()
+	ethEndpoint := newTestEthEndpoint(store)
+
+	// Account doesn't have any balance
+	store.account.account.Balance = big.NewInt(0)
+
+	// The transaction has a value > 0
+	from := types.StringToAddress("0xSenderAddress")
+	mockTx := constructMockTx(nil, nil)
+	mockTx.From = &from
+	mockTx.Input = argBytesPtr([]byte{})
+	mockTx.To = nil
+
+	// Run the estimation
+	estimate, err := ethEndpoint.EstimateGas(
+		mockTx,
+		nil,
+	)
 
-	// Make sure the insufficient funds error message is contained
-	assert.ErrorIs(t, estimateErr, ErrInsufficientFunds)
+	assert.NotNil(t, estimate)
+	estimateUint64, ok := estimate.(argUint64)
+	assert.True(t, ok)
+	assert.NoError(t, err)
+	assert.Equal(t, state.TxGasContractCreation, uint64(estimateUint64))
 }
 
 type mockSpecialStore struct {
@@ -867,7 +899,7 @@ func (m *mockSpecialStore) GetCode(root types.Hash, addr types.Address) ([]byte,
 }
 
 func (m *mockSpecialStore) GetForksInTime(blockNumber uint64) chain.ForksInTime {
-	return chain.ForksInTime{}
+	return chain.AllForksEnabled.At(0)
 }
 
 func (m *mockSpecialStore) ApplyTxn(header *types.Header, txn *types.Transaction, _ types.StateOverride, _ bool) (*runtime.ExecutionResult, error) {

types/transaction.go

@@ -74,6 +74,14 @@ func (t *Transaction) IsContractCreation() bool {
 	return t.To == nil
 }
 
+// IsValueTransfer checks if tx is a value transfer
+func (t *Transaction) IsValueTransfer() bool {
+	return t.Value != nil &&
+		t.Value.Sign() > 0 &&
+		len(t.Input) == 0 &&
+		!t.IsContractCreation()
+}
+
 // ComputeHash computes the hash of the transaction
 func (t *Transaction) ComputeHash(blockNumber uint64) *Transaction {
 	GetTransactionHashHandler(blockNumber).ComputeHash(t)