accounts/abi: add basic support for error types (#23161)

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 #23157

Author: MariusVanDerWijden

accounts/abi/abi.go

@@ -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
@@ -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
@@ -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) {
@@ -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
+}

accounts/abi/abi_test.go

@@ -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 {

accounts/abi/bind/bind_test.go

@@ -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,

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
@@ -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:])
 }

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)
+}