abi: fix checks when all fields are indexed (#24792)

This PR fixes abi checks in the edge case where all arguments are indexed

Author: rachel-bousfield

accounts/abi/argument.go

@@ -78,7 +78,7 @@ func (arguments Arguments) isTuple() bool {
 // Unpack performs the operation hexdata -> Go format.
 func (arguments Arguments) Unpack(data []byte) ([]interface{}, error) {
 	if len(data) == 0 {
-		if len(arguments) != 0 {
+		if len(arguments.NonIndexed()) != 0 {
 			return nil, fmt.Errorf("abi: attempting to unmarshall an empty string while arguments are expected")
 		}
 		return make([]interface{}, 0), nil
@@ -93,7 +93,7 @@ func (arguments Arguments) UnpackIntoMap(v map[string]interface{}, data []byte)
 		return fmt.Errorf("abi: cannot unpack into a nil map")
 	}
 	if len(data) == 0 {
-		if len(arguments) != 0 {
+		if len(arguments.NonIndexed()) != 0 {
 			return fmt.Errorf("abi: attempting to unmarshall an empty string while arguments are expected")
 		}
 		return nil // Nothing to unmarshal, return
@@ -115,8 +115,8 @@ func (arguments Arguments) Copy(v interface{}, values []interface{}) error {
 		return fmt.Errorf("abi: Unpack(non-pointer %T)", v)
 	}
 	if len(values) == 0 {
-		if len(arguments) != 0 {
-			return fmt.Errorf("abi: attempting to copy no values while %d arguments are expected", len(arguments))
+		if len(arguments.NonIndexed()) != 0 {
+			return fmt.Errorf("abi: attempting to copy no values while arguments are expected")
 		}
 		return nil // Nothing to copy, return
 	}

accounts/abi/unpack_test.go

@@ -201,6 +201,23 @@ var unpackTests = []unpackTest{
 			IntOne *big.Int
 		}{big.NewInt(1)},
 	},
+	{
+		def:  `[{"type":"bool"}]`,
+		enc:  "",
+		want: false,
+		err:  "abi: attempting to unmarshall an empty string while arguments are expected",
+	},
+	{
+		def:  `[{"type":"bytes32","indexed":true},{"type":"uint256","indexed":false}]`,
+		enc:  "",
+		want: false,
+		err:  "abi: attempting to unmarshall an empty string while arguments are expected",
+	},
+	{
+		def:  `[{"type":"bool","indexed":true},{"type":"uint64","indexed":true}]`,
+		enc:  "",
+		want: false,
+	},
 }
 
 // TestLocalUnpackTests runs test specially designed only for unpacking.