estimator: fix access list decoding

Author: attente

lib/estimator/estimator.go

@@ -208,16 +208,12 @@ func accessList(
 	provider *ethrpc.Provider,
 ) (types.AccessList, error) {
 	into := func(raw json.RawMessage, ret *types.AccessList, strictness ethrpc.StrictnessLevel) error {
-		var response struct {
-			AccessList types.AccessList `json:"accessList,omitempty"`
-		}
-
-		err := json.Unmarshal(raw, &response)
+		decoded, err := decodeAccessListResponse(raw)
 		if err != nil {
-			return fmt.Errorf("unable to decode eth_createAccessList response: %w", err)
+			return err
 		}
 
-		*ret = response.AccessList
+		*ret = decoded
 		return nil
 	}
 
@@ -243,3 +239,34 @@ func accessList(
 
 	return list, nil
 }
+
+func decodeAccessListResponse(raw json.RawMessage) (types.AccessList, error) {
+	type accessTuple struct {
+		Address     *common.Address `json:"address"`
+		StorageKeys []common.Hash   `json:"storageKeys"`
+	}
+
+	var response struct {
+		AccessList []accessTuple `json:"accessList,omitempty"`
+	}
+
+	err := json.Unmarshal(raw, &response)
+	if err != nil {
+		return nil, fmt.Errorf("unable to decode eth_createAccessList response: %w", err)
+	}
+
+	list := make(types.AccessList, 0, len(response.AccessList))
+
+	for _, tuple := range response.AccessList {
+		if tuple.Address == nil {
+			return nil, fmt.Errorf("unable to decode eth_createAccessList response: missing required field 'address' for AccessTuple")
+		}
+
+		list = append(list, types.AccessTuple{
+			Address:     *tuple.Address,
+			StorageKeys: tuple.StorageKeys,
+		})
+	}
+
+	return list, nil
+}

lib/estimator/estimator_internal_test.go

@@ -0,0 +1,37 @@
+package estimator
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/0xsequence/ethkit/go-ethereum/common"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestDecodeAccessListResponseAllowsMissingStorageKeys(t *testing.T) {
+	address := common.HexToAddress("0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48")
+
+	list, err := decodeAccessListResponse(json.RawMessage(`{
+		"accessList": [
+			{
+				"address": "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48"
+			}
+		]
+	}`))
+	require.NoError(t, err)
+	require.Len(t, list, 1)
+	assert.Equal(t, address, list[0].Address)
+	assert.Nil(t, list[0].StorageKeys)
+}
+
+func TestDecodeAccessListResponseRequiresAddress(t *testing.T) {
+	_, err := decodeAccessListResponse(json.RawMessage(`{
+		"accessList": [
+			{
+				"storageKeys": []
+			}
+		]
+	}`))
+	require.EqualError(t, err, "unable to decode eth_createAccessList response: missing required field 'address' for AccessTuple")
+}