Fix empty response body deser in case of error response

aws/protocol/ec2query/error_utils.go

@@ -17,7 +17,7 @@ type ErrorComponents struct {
 // GetErrorResponseComponents returns the error components from a ec2query error response body
 func GetErrorResponseComponents(r io.Reader) (ErrorComponents, error) {
 	var er ErrorComponents
-	if err := xml.NewDecoder(r).Decode(&er); err != nil {
+	if err := xml.NewDecoder(r).Decode(&er); err != nil && err != io.EOF {
 		return ErrorComponents{}, fmt.Errorf("error while fetching xml error response code: %w", err)
 	}
 	return er, nil

aws/protocol/ec2query/error_utils_test.go

@@ -52,6 +52,9 @@ func TestGetResponseErrorCode(t *testing.T) {
 			expectedErrorMessage:   "Hi",
 			expectedErrorRequestID: "foo-id",
 		},
+		"no response body": {
+			errorResponse: bytes.NewReader([]byte(``)),
+		},
 	}
 
 	for name, c := range cases {

aws/protocol/xml/error_utils.go

@@ -18,8 +18,8 @@ type ErrorComponents struct {
 func GetErrorResponseComponents(r io.Reader, noErrorWrapping bool) (ErrorComponents, error) {
 	if noErrorWrapping {
 		var errResponse noWrappedErrorResponse
-		if err := xml.NewDecoder(r).Decode(&errResponse); err != nil {
-			return ErrorComponents{}, fmt.Errorf("error while deserializingg xml error response: %w", err)
+		if err := xml.NewDecoder(r).Decode(&errResponse); err != nil && err != io.EOF {
+			return ErrorComponents{}, fmt.Errorf("error while deserializing xml error response: %w", err)
 		}
 		return ErrorComponents{
 			Code:      errResponse.Code,
@@ -29,8 +29,8 @@ func GetErrorResponseComponents(r io.Reader, noErrorWrapping bool) (ErrorCompone
 	}
 
 	var errResponse wrappedErrorResponse
-	if err := xml.NewDecoder(r).Decode(&errResponse); err != nil {
-		return ErrorComponents{}, fmt.Errorf("error while deserializingg xml error response: %w", err)
+	if err := xml.NewDecoder(r).Decode(&errResponse); err != nil && err != io.EOF {
+		return ErrorComponents{}, fmt.Errorf("error while deserializing xml error response: %w", err)
 	}
 	return ErrorComponents{
 		Code:      errResponse.Code,

aws/protocol/xml/error_utils_test.go

@@ -42,6 +42,9 @@ func TestGetResponseErrorCode(t *testing.T) {
 			expectedErrorMessage:   "Hi",
 			expectedErrorRequestID: "foo-id",
 		},
+		"no response body": {
+			errorResponse: bytes.NewReader([]byte(``)),
+		},
 	}
 
 	for name, c := range cases {

service/internal/s3shared/xml_utils.go

@@ -4,7 +4,6 @@ import (
 	"encoding/xml"
 	"fmt"
 	"io"
-	"io/ioutil"
 )
 
 // ErrorComponents represents the error response fields
@@ -18,14 +17,9 @@ type ErrorComponents struct {
 
 // GetErrorResponseComponents returns the error fields from an xml error response body
 func GetErrorResponseComponents(r io.Reader) (ErrorComponents, error) {
-	rb, err := ioutil.ReadAll(r)
-	if err != nil {
-		return ErrorComponents{}, err
-	}
-
 	var errComponents ErrorComponents
-	if err := xml.Unmarshal(rb, &errComponents); err != nil {
-		return ErrorComponents{}, fmt.Errorf("error while deserializingg xml error response : %w", err)
+	if err := xml.NewDecoder(r).Decode(&errComponents); err != nil && err != io.EOF {
+		return ErrorComponents{}, fmt.Errorf("error while deserializing xml error response : %w", err)
 	}
-	return errComponents, err
+	return errComponents, nil
 }

service/s3/internal/customizations/unit_test.go

@@ -0,0 +1,57 @@
+package customizations_test
+
+import (
+	"context"
+	"errors"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	"github.com/aws/aws-sdk-go-v2/aws"
+	"github.com/aws/aws-sdk-go-v2/service/s3"
+
+	"github.com/awslabs/smithy-go"
+)
+
+func Test_HeadBucket(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(
+		func(w http.ResponseWriter, r *http.Request) {
+			w.WriteHeader(400)
+		}))
+	defer server.Close()
+
+	ctx, cancelFn := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancelFn()
+
+	cfg := aws.Config{
+		Region: "us-east-1",
+		EndpointResolver: aws.EndpointResolverFunc(func(service, region string) (aws.Endpoint, error) {
+			return aws.Endpoint{
+				URL:         server.URL,
+				SigningName: "s3",
+			}, nil
+		}),
+		Retryer: aws.NoOpRetryer{},
+	}
+
+	client := s3.NewFromConfig(cfg, func(options *s3.Options) {
+		options.UsePathStyle = true
+	})
+	params := &s3.HeadBucketInput{Bucket: aws.String("aws-sdk-go-data")}
+	_, err := client.HeadBucket(ctx, params)
+	if err == nil {
+		t.Error("expected error, got none")
+	}
+
+	var apiErr smithy.APIError
+	if !errors.As(err, &apiErr) {
+		t.Fatalf("expect error to be API error, was not, %v", err)
+	}
+	if len(apiErr.ErrorCode()) == 0 {
+		t.Errorf("expect non-empty error code")
+	}
+	if len(apiErr.ErrorMessage()) == 0 {
+		t.Errorf("expect non-empty error message")
+	}
+}