Skip debit/credit during gas estimation (#2258)

* Zero out fee tip and fee cap during gas estimation

* Skip debit/credit for estimateGas

core/state_transition.go

@@ -347,6 +347,9 @@ func (st *StateTransition) canPayFee(accountOwner common.Address, feeCurrency *c
 }
 
 func (st *StateTransition) debitFee(from common.Address, feeCurrency *common.Address) (err error) {
+	if st.evm.Config.SkipDebitCredit {
+		return nil
+	}
 	effectiveFee := new(big.Int).Mul(new(big.Int).SetUint64(st.msg.Gas()), st.gasPrice)
 	// If GatewayFeeRecipient is unspecified, the gateway fee value is ignore and the sender is not charged.
 	if st.msg.GatewayFeeRecipient() != nil {
@@ -527,6 +530,10 @@ func (st *StateTransition) TransitionDb() (*ExecutionResult, error) {
 
 // creditTxFees calculates the amounts and recipients of transaction fees and credits the accounts.
 func (st *StateTransition) creditTxFees() error {
+	if st.evm.Config.SkipDebitCredit {
+		return nil
+	}
+
 	// Run only primary evm.Call() with tracer
 	if st.evm.GetDebug() {
 		st.evm.SetDebug(false)

core/vm/interpreter.go

@@ -36,6 +36,9 @@ type Config struct {
 	JumpTable [256]*operation // EVM instruction table, automatically populated if unset
 
 	ExtraEips []int // Additional EIPS that are to be enabled
+
+	// Celo
+	SkipDebitCredit bool
 }
 
 // ScopeContext contains the things that are per-call, such as stack and memory,

internal/ethapi/api.go

@@ -909,7 +909,7 @@ func DoCall(ctx context.Context, b Backend, args TransactionArgs, blockNrOrHash
 	if err != nil {
 		return nil, err
 	}
-	evm, vmError, err := b.GetEVM(ctx, msg, state, header, &vm.Config{NoBaseFee: true})
+	evm, vmError, err := b.GetEVM(ctx, msg, state, header, &vm.Config{NoBaseFee: true, SkipDebitCredit: true})
 	if err != nil {
 		return nil, err
 	}
@@ -1014,6 +1014,9 @@ func DoEstimateGas(ctx context.Context, b Backend, args TransactionArgs, blockNr
 	// also fail with gas limit B, which may not be the case if the gas price is non-zero,
 	// depending on the account's balance.
 	args.GasPrice = nil
+	// If a fee tip or fee cap are passed, those will override the gas price, so zero them out as well.
+	args.MaxFeePerGas = nil
+	args.MaxPriorityFeePerGas = nil
 	// Create a helper to check if a gas allowance results in an executable transaction
 	executable := func(gas uint64) (bool, *core.ExecutionResult, error) {
 		args.Gas = (*hexutil.Uint64)(&gas)