accounts/abi/bind, eth: rely on getCode for sanity checks, not estimate and call

eth/api.go

@@ -52,15 +52,6 @@ import (
 	"golang.org/x/net/context"
 )
 
-// errNoCode is returned by call and transact operations for which the requested
-// recipient contract to operate on does not exist in the state db or does not
-// have any code associated with it (i.e. suicided).
-//
-// Please note, this error string is part of the RPC API and is expected by the
-// native contract bindings to signal this particular error. Do not change this
-// as it will break all dependent code!
-var errNoCode = errors.New("no contract code at given address")
-
 const defaultGas = uint64(90000)
 
 // blockByNumber is a commonly used helper function which retrieves and returns
@@ -717,12 +708,6 @@ func (s *PublicBlockChainAPI) doCall(args CallArgs, blockNr rpc.BlockNumber) (st
 	}
 	stateDb = stateDb.Copy()
 
-	// If there's no code to interact with, respond with an appropriate error
-	if args.To != nil {
-		if code := stateDb.GetCode(*args.To); len(code) == 0 {
-			return "0x", nil, errNoCode
-		}
-	}
 	// Retrieve the account state object to interact with
 	var from *state.StateObject
 	if args.From == (common.Address{}) {

eth/bind.go

@@ -19,7 +19,6 @@ package eth
 import (
 	"math/big"
 
-	"github.com/ethereum/go-ethereum/accounts/abi/bind"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/rlp"
@@ -49,6 +48,17 @@ func NewContractBackend(eth *Ethereum) *ContractBackend {
 	}
 }
 
+// HasCode implements bind.ContractVerifier.HasCode by retrieving any code associated
+// with the contract from the local API, and checking its size.
+func (b *ContractBackend) HasCode(contract common.Address, pending bool) (bool, error) {
+	block := rpc.LatestBlockNumber
+	if pending {
+		block = rpc.PendingBlockNumber
+	}
+	out, err := b.bcapi.GetCode(contract, block)
+	return len(common.FromHex(out)) > 0, err
+}
+
 // ContractCall implements bind.ContractCaller executing an Ethereum contract
 // call with the specified data as the input. The pending flag requests execution
 // against the pending block, not the stable head of the chain.
@@ -64,9 +74,6 @@ func (b *ContractBackend) ContractCall(contract common.Address, data []byte, pen
 	}
 	// Execute the call and convert the output back to Go types
 	out, err := b.bcapi.Call(args, block)
-	if err == errNoCode {
-		err = bind.ErrNoCode
-	}
 	return common.FromHex(out), err
 }
 
@@ -95,9 +102,6 @@ func (b *ContractBackend) EstimateGasLimit(sender common.Address, contract *comm
 		Value: *rpc.NewHexNumber(value),
 		Data:  common.ToHex(data),
 	})
-	if err == errNoCode {
-		err = bind.ErrNoCode
-	}
 	return out.BigInt(), err
 }