Fix GetBatchResponseById error deserialization (#249)

CHANGELOG.md

@@ -11,6 +11,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+## [1.0.2] - 2023-12-01
+
+### Changed
+
+- Fixed a bug where GetBatchResponseById failed to deserialize error response bodies.
+
 ## [1.0.1] - 2023-11-24
 
 ### Changed

batch_request_test.go

@@ -308,6 +308,56 @@ func TestGetResponseByIdFailedRequest(t *testing.T) {
 	assert.Equal(t, "The server returned an unexpected status code and no error factory is registered for this code: 401", err.Error())
 }
 
+func TestGetErrorResponseBodyById(t *testing.T) {
+	var jsonBlob = `{
+		"responses": [{
+			"id": "3",
+			"status": 400,
+			"headers": {
+				"Content-Type": "application/json"
+			},
+			"body": {
+				"error": {
+					"code": "ExtensionError",
+					"message": "Exception: [Status Code: BadRequest; Reason: Boom]",
+					"innerError": {
+						"request-id": "123"
+					}
+				}
+			}
+		}]
+	}`
+
+	errorMapping := abstractions.ErrorMappings{
+		"4XX": internal.CreateSampleErrorFromDiscriminatorValue,
+		"5XX": internal.CreateSampleErrorFromDiscriminatorValue,
+	}
+	err := RegisterError("Userable", errorMapping)
+	assert.NoError(t, err)
+
+	mockServer := makeMockRequest(200, jsonBlob)
+	defer mockServer.Close()
+
+	mockPath := mockServer.URL + "/$batch"
+	reqAdapter.SetBaseUrl(mockPath)
+
+	reqInfo := getRequestInfo()
+	batch := NewBatchRequest(reqAdapter)
+	_, err = batch.AddBatchRequestStep(*reqInfo)
+	require.NoError(t, err)
+
+	resp, err := batch.Send(context.Background(), reqAdapter)
+	require.NoError(t, err)
+
+	_, err = GetBatchResponseById[Userable](resp, "3", CreateUser)
+	serr := &internal.SampleError{}
+	assert.ErrorAs(t, err, &serr)
+	assert.Equal(t, "Exception: [Status Code: BadRequest; Reason: Boom]", serr.Message)
+
+	err = DeRegisterError("Userable")
+	require.NoError(t, err)
+}
+
 func TestGetResponseByIdFailedRequestWithFactory(t *testing.T) {
 	mockServer := makeMockRequest(200, getDummyJSON())
 	defer mockServer.Close()

batch_requests.go

@@ -6,7 +6,6 @@ import (
 	"encoding/gob"
 	"encoding/json"
 	"errors"
-	nethttplibrary "github.com/microsoft/kiota-http-go"
 	"net/url"
 	"reflect"
 	"strconv"
@@ -17,6 +16,7 @@ import (
 	abstractions "github.com/microsoft/kiota-abstractions-go"
 	"github.com/microsoft/kiota-abstractions-go/serialization"
 	absser "github.com/microsoft/kiota-abstractions-go/serialization"
+	nethttplibrary "github.com/microsoft/kiota-http-go"
 )
 
 const BatchRequestErrorRegistryKey = "BATCH_REQUEST_ERROR_REGISTRY_KEY"
@@ -210,13 +210,24 @@ func getRootParseNode(responseItem BatchItem) (absser.ParseNode, error) {
 	if contentType == "" {
 		return nil, nil
 	}
-	var buf bytes.Buffer
-	enc := gob.NewEncoder(&buf)
-	err := enc.Encode(responseItem.GetBody())
-	if err != nil {
-		return nil, err
+
+	var (
+		content []byte
+		err     error
+	)
+	if contentType == jsonContentType {
+		if content, err = json.Marshal(responseItem.GetBody()); err != nil {
+			return nil, err
+		}
+	} else {
+		var buf bytes.Buffer
+		if err = gob.NewEncoder(&buf).Encode(responseItem.GetBody()); err != nil {
+			return nil, err
+		}
+		content = buf.Bytes()
 	}
-	return serialization.DefaultParseNodeFactoryInstance.GetRootParseNode(contentType, buf.Bytes())
+
+	return serialization.DefaultParseNodeFactoryInstance.GetRootParseNode(contentType, content)
 }
 
 func throwErrors(responseItem BatchItem, typeName string) error {
@@ -266,7 +277,7 @@ func GetBatchResponseById[T serialization.Parsable](resp BatchResponse, itemId s
 	item := resp.GetResponseById(itemId)
 
 	if *item.GetStatus() >= 400 {
-		return res, throwErrors(item, reflect.TypeOf(new(T)).Name())
+		return res, throwErrors(item, reflect.TypeOf(new(T)).Elem().Name())
 	}
 
 	jsonStr, err := json.Marshal(item.GetBody())
@@ -282,7 +293,7 @@ func GetBatchResponseById[T serialization.Parsable](resp BatchResponse, itemId s
 	}
 
 	result, err := parseNode.GetObjectValue(constructor)
-	return result.(T), nil
+	return result.(T), err
 }
 
 func getErrorMapper(key string) abstractions.ErrorMappings {

internal/errors.go

@@ -15,8 +15,21 @@ func (s SampleError) Serialize(writer serialization.SerializationWriter) error {
 	return nil
 }
 
-func (s SampleError) GetFieldDeserializers() map[string]func(serialization.ParseNode) error {
-	return make(map[string]func(serialization.ParseNode) error)
+func (s *SampleError) GetFieldDeserializers() map[string]func(serialization.ParseNode) error {
+	res := make(map[string]func(serialization.ParseNode) error)
+	res["error"] = func(n serialization.ParseNode) error {
+		v, err := n.GetRawValue()
+		if err != nil {
+			return err
+		}
+		if vm, ok := v.(map[string]interface{}); ok {
+			if msg, ok := vm["message"]; ok && msg != nil {
+				s.Message = *msg.(*string)
+			}
+		}
+		return nil
+	}
+	return res
 }
 
 func CreateSampleErrorFromDiscriminatorValue(parseNode serialization.ParseNode) (serialization.Parsable, error) {