Azure function throws "Message processing error(Action=Complete)" after calling deadletterasync with autocomplete not setting as False

Question

Azure function throws "Message processing error(Action=Complete)" after calling deadletterasync with autocomplete not setting as False. But when I set "Autocomplete=false" even after processing successful messages it keeps retrying. What is the best way to receive message ,and deadletter when exception occurs?

public async Task Test(
        [ServiceBusTrigger(
            topicName: "testTopic",
            subscriptionName: "testSubsription",
            Connection = "testConnectionString",Autocomplete = false)]
        Message message,
        MessageReceiver messageReceiver,
        [ServiceBus("SendTopic", EntityType.Topic, Connection = "SendConnection")]
        IAsyncCollector<Message> output,
        CancellationToken cancellationToken)
     {
        try
        { 

            var result = JsonConvert.DeserializeObject<TestObject>(Encoding.UTF8.GetString(message.Body));
            foreach (var data in result.Data)
            {
               var convertedData= JsonConvert.SerializeObject(data);
               var byteArray = Encoding.UTF8.GetBytes(convertedData);
               Message outputMessages = new(byteArray);
               await output.AddAsync(outputMessages, cancellationToken);
               await messageReceiver.CompleteAsync(lockToken);
            }
        }
        catch (Exception ex)
        {
          await messageReceiver.DeadLetterAsync(lockToken);
        }
    }

Answer 1

In your code, you're using the message receiver to settle (dead-letter) the message. Instead, you should inject SerivceBusMessageActions and use it to settle the message manually.