accounts/abi: improve unpack performance (#31387)

Slightly improves performance of abi.Unpack

```
Before
BenchmarkUnpack/0-14   5965714       210.9 ns/op     280 B/op       5 allocs/op
BenchmarkUnpack/1-14   2148283       569.7 ns/op     688 B/op      16 allocs/op

After:
BenchmarkUnpack/0-14  	 7693365	       151.2 ns/op	     136 B/op	       4 allocs/op
BenchmarkUnpack/1-14  	 2261294	       508.9 ns/op	     544 B/op	      15 allocs/op
```

replaces https://github.com/ethereum/go-ethereum/pull/31292 since I was
unable to push to your branch @Exca-DK

---------

Co-authored-by: Exca-DK <dawidk.info@gmail.com>

accounts/abi/argument.go

@@ -77,18 +77,18 @@ func (arguments Arguments) isTuple() bool {
 }
 
 // Unpack performs the operation hexdata -> Go format.
-func (arguments Arguments) Unpack(data []byte) ([]interface{}, error) {
+func (arguments Arguments) Unpack(data []byte) ([]any, error) {
 	if len(data) == 0 {
 		if len(arguments.NonIndexed()) != 0 {
 			return nil, errors.New("abi: attempting to unmarshal an empty string while arguments are expected")
 		}
-		return make([]interface{}, 0), nil
+		return make([]any, 0), nil
 	}
 	return arguments.UnpackValues(data)
 }
 
 // UnpackIntoMap performs the operation hexdata -> mapping of argument name to argument value.
-func (arguments Arguments) UnpackIntoMap(v map[string]interface{}, data []byte) error {
+func (arguments Arguments) UnpackIntoMap(v map[string]any, data []byte) error {
 	// Make sure map is not nil
 	if v == nil {
 		return errors.New("abi: cannot unpack into a nil map")
@@ -110,7 +110,7 @@ func (arguments Arguments) UnpackIntoMap(v map[string]interface{}, data []byte)
 }
 
 // Copy performs the operation go format -> provided struct.
-func (arguments Arguments) Copy(v interface{}, values []interface{}) error {
+func (arguments Arguments) Copy(v any, values []any) error {
 	// make sure the passed value is arguments pointer
 	if reflect.Ptr != reflect.ValueOf(v).Kind() {
 		return fmt.Errorf("abi: Unpack(non-pointer %T)", v)
@@ -128,7 +128,7 @@ func (arguments Arguments) Copy(v interface{}, values []interface{}) error {
 }
 
 // copyAtomic copies ( hexdata -> go ) a single value
-func (arguments Arguments) copyAtomic(v interface{}, marshalledValues interface{}) error {
+func (arguments Arguments) copyAtomic(v any, marshalledValues any) error {
 	dst := reflect.ValueOf(v).Elem()
 	src := reflect.ValueOf(marshalledValues)
 
@@ -139,7 +139,7 @@ func (arguments Arguments) copyAtomic(v interface{}, marshalledValues interface{
 }
 
 // copyTuple copies a batch of values from marshalledValues to v.
-func (arguments Arguments) copyTuple(v interface{}, marshalledValues []interface{}) error {
+func (arguments Arguments) copyTuple(v any, marshalledValues []any) error {
 	value := reflect.ValueOf(v).Elem()
 	nonIndexedArgs := arguments.NonIndexed()
 
@@ -181,11 +181,17 @@ func (arguments Arguments) copyTuple(v interface{}, marshalledValues []interface
 // UnpackValues can be used to unpack ABI-encoded hexdata according to the ABI-specification,
 // without supplying a struct to unpack into. Instead, this method returns a list containing the
 // values. An atomic argument will be a list with one element.
-func (arguments Arguments) UnpackValues(data []byte) ([]interface{}, error) {
-	nonIndexedArgs := arguments.NonIndexed()
-	retval := make([]interface{}, 0, len(nonIndexedArgs))
-	virtualArgs := 0
-	for index, arg := range nonIndexedArgs {
+func (arguments Arguments) UnpackValues(data []byte) ([]any, error) {
+	var (
+		retval      = make([]any, 0)
+		virtualArgs = 0
+		index       = 0
+	)
+
+	for _, arg := range arguments {
+		if arg.Indexed {
+			continue
+		}
 		marshalledValue, err := toGoType((index+virtualArgs)*32, arg.Type, data)
 		if err != nil {
 			return nil, err
@@ -208,18 +214,19 @@ func (arguments Arguments) UnpackValues(data []byte) ([]interface{}, error) {
 			virtualArgs += getTypeSize(arg.Type)/32 - 1
 		}
 		retval = append(retval, marshalledValue)
+		index++
 	}
 	return retval, nil
 }
 
 // PackValues performs the operation Go format -> Hexdata.
 // It is the semantic opposite of UnpackValues.
-func (arguments Arguments) PackValues(args []interface{}) ([]byte, error) {
+func (arguments Arguments) PackValues(args []any) ([]byte, error) {
 	return arguments.Pack(args...)
 }
 
 // Pack performs the operation Go format -> Hexdata.
-func (arguments Arguments) Pack(args ...interface{}) ([]byte, error) {
+func (arguments Arguments) Pack(args ...any) ([]byte, error) {
 	// Make sure arguments match up and pack them
 	abiArgs := arguments
 	if len(args) != len(abiArgs) {

accounts/abi/unpack_test.go

@@ -31,6 +31,46 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
+func BenchmarkUnpack(b *testing.B) {
+	testCases := []struct {
+		def    string
+		packed string
+	}{
+		{
+			def:    `[{"type": "uint32"}]`,
+			packed: "0000000000000000000000000000000000000000000000000000000000000001",
+		},
+		{
+			def: `[{"type": "uint32[]"}]`,
+			packed: "0000000000000000000000000000000000000000000000000000000000000020" +
+				"0000000000000000000000000000000000000000000000000000000000000002" +
+				"0000000000000000000000000000000000000000000000000000000000000001" +
+				"0000000000000000000000000000000000000000000000000000000000000002",
+		},
+	}
+	for i, test := range testCases {
+		b.Run(strconv.Itoa(i), func(b *testing.B) {
+			def := fmt.Sprintf(`[{ "name" : "method", "type": "function", "outputs": %s}]`, test.def)
+			abi, err := JSON(strings.NewReader(def))
+			if err != nil {
+				b.Fatalf("invalid ABI definition %s: %v", def, err)
+			}
+			encb, err := hex.DecodeString(test.packed)
+			if err != nil {
+				b.Fatalf("invalid hex %s: %v", test.packed, err)
+			}
+
+			b.ResetTimer()
+
+			var result any
+			for range b.N {
+				result, _ = abi.Unpack("method", encb)
+			}
+			_ = result
+		})
+	}
+}
+
 // TestUnpack tests the general pack/unpack tests in packing_test.go
 func TestUnpack(t *testing.T) {
 	t.Parallel()