api: ListMultipartUploads and ListParts responded more entries.

Issue is empty entries were added since allocating an array was
followed by an append. Keep the index and copy the right entries
precisely.

Fixes an issue reported at - https://github.com/minio/mc/issues/1642

api-response.go

@@ -359,13 +359,13 @@ func generateListPartsResponse(objectMetadata fs.ObjectResourcesMetadata) ListPa
 	listPartsResponse.NextPartNumberMarker = objectMetadata.NextPartNumberMarker
 
 	listPartsResponse.Parts = make([]Part, len(objectMetadata.Part))
-	for _, part := range objectMetadata.Part {
+	for index, part := range objectMetadata.Part {
 		newPart := Part{}
 		newPart.PartNumber = part.PartNumber
 		newPart.ETag = "\"" + part.ETag + "\""
 		newPart.Size = part.Size
 		newPart.LastModified = part.LastModified.UTC().Format(timeFormatAMZ)
-		listPartsResponse.Parts = append(listPartsResponse.Parts, newPart)
+		listPartsResponse.Parts[index] = newPart
 	}
 	return listPartsResponse
 }
@@ -385,12 +385,12 @@ func generateListMultipartUploadsResponse(bucket string, metadata fs.BucketMulti
 	listMultipartUploadsResponse.UploadIDMarker = metadata.UploadIDMarker
 
 	listMultipartUploadsResponse.Uploads = make([]Upload, len(metadata.Upload))
-	for _, upload := range metadata.Upload {
+	for index, upload := range metadata.Upload {
 		newUpload := Upload{}
 		newUpload.UploadID = upload.UploadID
 		newUpload.Key = upload.Object
-		newUpload.Initiated = upload.Initiated.Format(timeFormatAMZ)
-		listMultipartUploadsResponse.Uploads = append(listMultipartUploadsResponse.Uploads, newUpload)
+		newUpload.Initiated = upload.Initiated.UTC().Format(timeFormatAMZ)
+		listMultipartUploadsResponse.Uploads[index] = newUpload
 	}
 	return listMultipartUploadsResponse
 }

server_fs_test.go

@@ -1103,8 +1103,34 @@ func (s *MyAPIFSCacheSuite) TestBucketMultipartList(c *C) {
 	c.Assert(err, IsNil)
 	c.Assert(response3.StatusCode, Equals, http.StatusOK)
 
+	// listMultipartUploadsResponse - format for list multipart uploads response.
+	type listMultipartUploadsResponse struct {
+		XMLName xml.Name `xml:"http://s3.amazonaws.com/doc/2006-03-01/ ListMultipartUploadsResult" json:"-"`
+
+		Bucket             string
+		KeyMarker          string
+		UploadIDMarker     string `xml:"UploadIdMarker"`
+		NextKeyMarker      string
+		NextUploadIDMarker string `xml:"NextUploadIdMarker"`
+		EncodingType       string
+		MaxUploads         int
+		IsTruncated        bool
+		// All the in progress multipart uploads.
+		Uploads []struct {
+			Key          string
+			UploadID     string `xml:"UploadId"`
+			Initiator    Initiator
+			Owner        Owner
+			StorageClass string
+			Initiated    time.Time // Keep this native to be able to parse properly.
+		}
+		Prefix         string
+		Delimiter      string
+		CommonPrefixes []CommonPrefix
+	}
+
 	decoder = xml.NewDecoder(response3.Body)
-	newResponse3 := &ListMultipartUploadsResponse{}
+	newResponse3 := &listMultipartUploadsResponse{}
 	err = decoder.Decode(newResponse3)
 	c.Assert(err, IsNil)
 	c.Assert(newResponse3.Bucket, Equals, "bucketmultipartlist")