Skip to content

Commit

Permalink
accounts/abi: add basic support for error types (ethereum#23161)
Browse files Browse the repository at this point in the history
This is the initial step for support of Solidity errors in contract bindings.
As of this change, errors can be decoded, but are not supported in
bindings yet.

Closes ethereum#23157
  • Loading branch information
MariusVanDerWijden authored and jagdeep sidhu committed Oct 14, 2021
1 parent 62a5c24 commit f6b792e
Show file tree
Hide file tree
Showing 5 changed files with 230 additions and 79 deletions.
55 changes: 23 additions & 32 deletions accounts/abi/abi.go
Expand Up @@ -34,6 +34,7 @@ type ABI struct {
Constructor Method
Methods map[string]Method
Events map[string]Event
Errors map[string]Error

// Additional "special" functions introduced in solidity v0.6.0.
// It's separated from the original default fallback. Each contract
Expand Down Expand Up @@ -157,12 +158,13 @@ func (abi *ABI) UnmarshalJSON(data []byte) error {
}
abi.Methods = make(map[string]Method)
abi.Events = make(map[string]Event)
abi.Errors = make(map[string]Error)
for _, field := range fields {
switch field.Type {
case "constructor":
abi.Constructor = NewMethod("", "", Constructor, field.StateMutability, field.Constant, field.Payable, field.Inputs, nil)
case "function":
name := abi.overloadedMethodName(field.Name)
name := overloadedName(field.Name, func(s string) bool { _, ok := abi.Methods[s]; return ok })
abi.Methods[name] = NewMethod(name, field.Name, Function, field.StateMutability, field.Constant, field.Payable, field.Inputs, field.Outputs)
case "fallback":
// New introduced function type in v0.6.0, check more detail
Expand All @@ -182,45 +184,17 @@ func (abi *ABI) UnmarshalJSON(data []byte) error {
}
abi.Receive = NewMethod("", "", Receive, field.StateMutability, field.Constant, field.Payable, nil, nil)
case "event":
name := abi.overloadedEventName(field.Name)
name := overloadedName(field.Name, func(s string) bool { _, ok := abi.Events[s]; return ok })
abi.Events[name] = NewEvent(name, field.Name, field.Anonymous, field.Inputs)
case "error":
abi.Errors[field.Name] = NewError(field.Name, field.Inputs)
default:
return fmt.Errorf("abi: could not recognize type %v of field %v", field.Type, field.Name)
}
}
return nil
}

// overloadedMethodName returns the next available name for a given function.
// Needed since solidity allows for function overload.
//
// e.g. if the abi contains Methods send, send1
// overloadedMethodName would return send2 for input send.
func (abi *ABI) overloadedMethodName(rawName string) string {
name := rawName
_, ok := abi.Methods[name]
for idx := 0; ok; idx++ {
name = fmt.Sprintf("%s%d", rawName, idx)
_, ok = abi.Methods[name]
}
return name
}

// overloadedEventName returns the next available name for a given event.
// Needed since solidity allows for event overload.
//
// e.g. if the abi contains events received, received1
// overloadedEventName would return received2 for input received.
func (abi *ABI) overloadedEventName(rawName string) string {
name := rawName
_, ok := abi.Events[name]
for idx := 0; ok; idx++ {
name = fmt.Sprintf("%s%d", rawName, idx)
_, ok = abi.Events[name]
}
return name
}

// MethodById looks up a method by the 4-byte id,
// returns nil if none found.
func (abi *ABI) MethodById(sigdata []byte) (*Method, error) {
Expand Down Expand Up @@ -277,3 +251,20 @@ func UnpackRevert(data []byte) (string, error) {
}
return unpacked[0].(string), nil
}

// overloadedName returns the next available name for a given thing.
// Needed since solidity allows for overloading.
//
// e.g. if the abi contains Methods send, send1
// overloadedName would return send2 for input send.
//
// overloadedName works for methods, events and errors.
func overloadedName(rawName string, isAvail func(string) bool) string {
name := rawName
ok := isAvail(name)
for idx := 0; ok; idx++ {
name = fmt.Sprintf("%s%d", rawName, idx)
ok = isAvail(name)
}
return name
}
14 changes: 14 additions & 0 deletions accounts/abi/abi_test.go
Expand Up @@ -295,6 +295,20 @@ func TestOverloadedMethodSignature(t *testing.T) {
check("bar0", "bar(uint256,uint256)", false)
}

func TestCustomErrors(t *testing.T) {
json := `[{ "inputs": [ { "internalType": "uint256", "name": "", "type": "uint256" } ],"name": "MyError", "type": "error"} ]`
abi, err := JSON(strings.NewReader(json))
if err != nil {
t.Fatal(err)
}
check := func(name string, expect string) {
if abi.Errors[name].Sig != expect {
t.Fatalf("The signature of overloaded method mismatch, want %s, have %s", expect, abi.Methods[name].Sig)
}
}
check("MyError", "MyError(uint256)")
}

func TestMultiPack(t *testing.T) {
abi, err := JSON(strings.NewReader(jsondata))
if err != nil {
Expand Down
55 changes: 55 additions & 0 deletions accounts/abi/bind/bind_test.go
Expand Up @@ -1850,6 +1850,61 @@ var bindTests = []struct {
if count != 1 {
t.Fatal("Unexpected contract event number")
}
`,
nil,
nil,
nil,
nil,
},
// Test errors introduced in v0.8.4
{
`NewErrors`,
`
pragma solidity >0.8.4;
contract NewErrors {
error MyError(uint256);
error MyError1(uint256);
error MyError2(uint256, uint256);
error MyError3(uint256 a, uint256 b, uint256 c);
function Error() public pure {
revert MyError3(1,2,3);
}
}
`,
[]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"}]`},
`
"math/big"
"github.com/ethereum/go-ethereum/accounts/abi/bind"
"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
"github.com/ethereum/go-ethereum/core"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/eth/ethconfig"
`,
`
var (
key, _ = crypto.GenerateKey()
user, _ = bind.NewKeyedTransactorWithChainID(key, big.NewInt(1337))
sim = backends.NewSimulatedBackend(core.GenesisAlloc{user.From: {Balance: big.NewInt(1000000000000000000)}}, ethconfig.Defaults.Miner.GasCeil)
)
defer sim.Close()
_, tx, contract, err := DeployNewErrors(user, sim)
if err != nil {
t.Fatal(err)
}
sim.Commit()
_, err = bind.WaitDeployed(nil, sim, tx)
if err != nil {
t.Error(err)
}
if err := contract.Error(new(bind.CallOpts)); err == nil {
t.Fatalf("expected contract to throw error")
}
// TODO (MariusVanDerWijden unpack error using abigen
// once that is implemented
`,
nil,
nil,
Expand Down
103 changes: 56 additions & 47 deletions accounts/abi/error.go
@@ -1,4 +1,4 @@
// Copyright 2016 The go-ethereum Authors
// Copyright 2021 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
Expand All @@ -17,66 +17,75 @@
package abi

import (
"bytes"
"errors"
"fmt"
"reflect"
)
"strings"

var (
errBadBool = errors.New("abi: improperly encoded boolean value")
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/crypto"
)

// formatSliceString formats the reflection kind with the given slice size
// and returns a formatted string representation.
func formatSliceString(kind reflect.Kind, sliceSize int) string {
if sliceSize == -1 {
return fmt.Sprintf("[]%v", kind)
}
return fmt.Sprintf("[%d]%v", sliceSize, kind)
type Error struct {
Name string
Inputs Arguments
str string
// Sig contains the string signature according to the ABI spec.
// e.g. event foo(uint32 a, int b) = "foo(uint32,int256)"
// Please note that "int" is substitute for its canonical representation "int256"
Sig string
// ID returns the canonical representation of the event's signature used by the
// abi definition to identify event names and types.
ID common.Hash
}

// sliceTypeCheck checks that the given slice can by assigned to the reflection
// type in t.
func sliceTypeCheck(t Type, val reflect.Value) error {
if val.Kind() != reflect.Slice && val.Kind() != reflect.Array {
return typeErr(formatSliceString(t.GetType().Kind(), t.Size), val.Type())
func NewError(name string, inputs Arguments) Error {
// sanitize inputs to remove inputs without names
// and precompute string and sig representation.
names := make([]string, len(inputs))
types := make([]string, len(inputs))
for i, input := range inputs {
if input.Name == "" {
inputs[i] = Argument{
Name: fmt.Sprintf("arg%d", i),
Indexed: input.Indexed,
Type: input.Type,
}
} else {
inputs[i] = input
}
// string representation
names[i] = fmt.Sprintf("%v %v", input.Type, inputs[i].Name)
if input.Indexed {
names[i] = fmt.Sprintf("%v indexed %v", input.Type, inputs[i].Name)
}
// sig representation
types[i] = input.Type.String()
}

if t.T == ArrayTy && val.Len() != t.Size {
return typeErr(formatSliceString(t.Elem.GetType().Kind(), t.Size), formatSliceString(val.Type().Elem().Kind(), val.Len()))
}
str := fmt.Sprintf("error %v(%v)", name, strings.Join(names, ", "))
sig := fmt.Sprintf("%v(%v)", name, strings.Join(types, ","))
id := common.BytesToHash(crypto.Keccak256([]byte(sig)))

if t.Elem.T == SliceTy || t.Elem.T == ArrayTy {
if val.Len() > 0 {
return sliceTypeCheck(*t.Elem, val.Index(0))
}
return Error{
Name: name,
Inputs: inputs,
str: str,
Sig: sig,
ID: id,
}
}

if val.Type().Elem().Kind() != t.Elem.GetType().Kind() {
return typeErr(formatSliceString(t.Elem.GetType().Kind(), t.Size), val.Type())
}
return nil
func (e *Error) String() string {
return e.str
}

// typeCheck checks that the given reflection value can be assigned to the reflection
// type in t.
func typeCheck(t Type, value reflect.Value) error {
if t.T == SliceTy || t.T == ArrayTy {
return sliceTypeCheck(t, value)
func (e *Error) Unpack(data []byte) (interface{}, error) {
if len(data) < 4 {
return "", errors.New("invalid data for unpacking")
}

// Check base type validity. Element types will be checked later on.
if t.GetType().Kind() != value.Kind() {
return typeErr(t.GetType().Kind(), value.Kind())
} else if t.T == FixedBytesTy && t.Size != value.Len() {
return typeErr(t.GetType(), value.Type())
} else {
return nil
if !bytes.Equal(data[:4], e.ID[:4]) {
return "", errors.New("invalid data for unpacking")
}

}

// typeErr returns a formatted type casting error.
func typeErr(expected, got interface{}) error {
return fmt.Errorf("abi: cannot use %v as type %v as argument", got, expected)
return e.Inputs.Unpack(data[4:])
}
82 changes: 82 additions & 0 deletions accounts/abi/error_handling.go
@@ -0,0 +1,82 @@
// Copyright 2016 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package abi

import (
"errors"
"fmt"
"reflect"
)

var (
errBadBool = errors.New("abi: improperly encoded boolean value")
)

// formatSliceString formats the reflection kind with the given slice size
// and returns a formatted string representation.
func formatSliceString(kind reflect.Kind, sliceSize int) string {
if sliceSize == -1 {
return fmt.Sprintf("[]%v", kind)
}
return fmt.Sprintf("[%d]%v", sliceSize, kind)
}

// sliceTypeCheck checks that the given slice can by assigned to the reflection
// type in t.
func sliceTypeCheck(t Type, val reflect.Value) error {
if val.Kind() != reflect.Slice && val.Kind() != reflect.Array {
return typeErr(formatSliceString(t.GetType().Kind(), t.Size), val.Type())
}

if t.T == ArrayTy && val.Len() != t.Size {
return typeErr(formatSliceString(t.Elem.GetType().Kind(), t.Size), formatSliceString(val.Type().Elem().Kind(), val.Len()))
}

if t.Elem.T == SliceTy || t.Elem.T == ArrayTy {
if val.Len() > 0 {
return sliceTypeCheck(*t.Elem, val.Index(0))
}
}

if val.Type().Elem().Kind() != t.Elem.GetType().Kind() {
return typeErr(formatSliceString(t.Elem.GetType().Kind(), t.Size), val.Type())
}
return nil
}

// typeCheck checks that the given reflection value can be assigned to the reflection
// type in t.
func typeCheck(t Type, value reflect.Value) error {
if t.T == SliceTy || t.T == ArrayTy {
return sliceTypeCheck(t, value)
}

// Check base type validity. Element types will be checked later on.
if t.GetType().Kind() != value.Kind() {
return typeErr(t.GetType().Kind(), value.Kind())
} else if t.T == FixedBytesTy && t.Size != value.Len() {
return typeErr(t.GetType(), value.Type())
} else {
return nil
}

}

// typeErr returns a formatted type casting error.
func typeErr(expected, got interface{}) error {
return fmt.Errorf("abi: cannot use %v as type %v as argument", got, expected)
}

0 comments on commit f6b792e

Please sign in to comment.