internal/ethapi: return revert reason for eth_call (ethereum#21083)

* internal/ethapi: return revert reason for eth_call

* internal/ethapi: moved revert reason logic to doCall

* accounts/abi/bind/backends: added revert reason logic to simulated backend

* internal/ethapi: fixed linting error

* internal/ethapi: check if require reason can be unpacked

* internal/ethapi: better error logic

* internal/ethapi: simplify logic

* internal/ethapi: return vmError()

* internal/ethapi: move handling of revert out of docall

* graphql: removed revert logic until spec change

* rpc: internal/ethapi: added custom error types

* graphql: use returndata instead of return

Return() checks if there is an error. If an error is found, we return nil.
For most use cases it can be beneficial to return the output even if there
was an error. This code should be changed anyway once the spec supports
error reasons in graphql responses

* accounts/abi/bind/backends: added tests for revert reason

* internal/ethapi: add errorCode to revert error

* internal/ethapi: add errorCode of 3 to revertError

* internal/ethapi: unified estimateGasErrors, simplified logic

* internal/ethapi: unified handling of errors in DoEstimateGas

* rpc: print error data field

* accounts/abi/bind/backends: unify simulatedBackend and RPC

* internal/ethapi: added binary data to revertError data

* internal/ethapi: refactored unpacking logic into newRevertError

* accounts/abi/bind/backends: fix EstimateGas

* accounts, console, internal, rpc: minor error interface cleanups

* Revert "accounts, console, internal, rpc: minor error interface cleanups"

This reverts commit 2d3ef53.

* re-apply the good parts of 2d3ef53

* rpc: add test for returning server error data from client

Co-authored-by: rjl493456442 <[email protected]>
Co-authored-by: Péter Szilágyi <[email protected]>
Co-authored-by: Felix Lange <[email protected]>

accounts/abi/bind/backends/simulated.go

@@ -28,6 +28,7 @@ import (
 	"github.com/ethereum/go-ethereum/accounts/abi"
 	"github.com/ethereum/go-ethereum/accounts/abi/bind"
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/ethereum/go-ethereum/common/math"
 	"github.com/ethereum/go-ethereum/consensus/ethash"
 	"github.com/ethereum/go-ethereum/core"
@@ -344,6 +345,36 @@ func (b *SimulatedBackend) PendingCodeAt(ctx context.Context, contract common.Ad
 	return b.pendingState.GetCode(contract), nil
 }
 
+func newRevertError(result *core.ExecutionResult) *revertError {
+	reason, errUnpack := abi.UnpackRevert(result.Revert())
+	err := errors.New("execution reverted")
+	if errUnpack == nil {
+		err = fmt.Errorf("execution reverted: %v", reason)
+	}
+	return &revertError{
+		error:  err,
+		reason: hexutil.Encode(result.Revert()),
+	}
+}
+
+// revertError is an API error that encompassas an EVM revertal with JSON error
+// code and a binary data blob.
+type revertError struct {
+	error
+	reason string // revert reason hex encoded
+}
+
+// ErrorCode returns the JSON error code for a revertal.
+// See: https://github.com/ethereum/wiki/wiki/JSON-RPC-Error-Codes-Improvement-Proposal
+func (e *revertError) ErrorCode() int {
+	return 3
+}
+
+// ErrorData returns the hex encoded revert reason.
+func (e *revertError) ErrorData() interface{} {
+	return e.reason
+}
+
 // CallContract executes a contract call.
 func (b *SimulatedBackend) CallContract(ctx context.Context, call ethereum.CallMsg, blockNumber *big.Int) ([]byte, error) {
 	b.mu.Lock()
@@ -360,7 +391,11 @@ func (b *SimulatedBackend) CallContract(ctx context.Context, call ethereum.CallM
 	if err != nil {
 		return nil, err
 	}
-	return res.Return(), nil
+	// If the result contains a revert reason, try to unpack and return it.
+	if len(res.Revert()) > 0 {
+		return nil, newRevertError(res)
+	}
+	return res.Return(), res.Err
 }
 
 // PendingCallContract executes a contract call on the pending state.
@@ -373,7 +408,11 @@ func (b *SimulatedBackend) PendingCallContract(ctx context.Context, call ethereu
 	if err != nil {
 		return nil, err
 	}
-	return res.Return(), nil
+	// If the result contains a revert reason, try to unpack and return it.
+	if len(res.Revert()) > 0 {
+		return nil, newRevertError(res)
+	}
+	return res.Return(), res.Err
 }
 
 // PendingNonceAt implements PendingStateReader.PendingNonceAt, retrieving
@@ -472,16 +511,10 @@ func (b *SimulatedBackend) EstimateGas(ctx context.Context, call ethereum.CallMs
 		}
 		if failed {
 			if result != nil && result.Err != vm.ErrOutOfGas {
-				errMsg := fmt.Sprintf("always failing transaction (%v)", result.Err)
 				if len(result.Revert()) > 0 {
-					ret, err := abi.UnpackRevert(result.Revert())
-					if err != nil {
-						errMsg += fmt.Sprintf(" (%#x)", result.Revert())
-					} else {
-						errMsg += fmt.Sprintf(" (%s)", ret)
-					}
+					return 0, newRevertError(result)
 				}
-				return 0, errors.New(errMsg)
+				return 0, result.Err
 			}
 			// Otherwise, the specified gas cap is too low
 			return 0, fmt.Errorf("gas required exceeds allowance (%d)", cap)