IaC Error Queue not respected with Topic

[jjnrmason]

Describe the bug
Error Queue is created when DLQ is already configured on the queue.

Steps To reproduce
Create my infrastructure using CDK before I run my apps. I create

• A single queue with an error queue associated
• A single topic
• A single subscription to the topic and link the queue
  This all links correctly and deploys nothing amis.

Via JustSayings configuration I do the following:

busBuilder.Subscriptions(subscriptionsBuilder => {
    subscriptionsBuilder.ForQueueUri<OrderCreatedEvent>(new Uri(builder.Configuration.GetSection("QueueConfig:OrderQueueUrl").Get<string>()!));
    subscriptionsBuilder.ForTopic<OrderCreatedEvent>(cfg => cfg
        .WithTopicName(builder.Configuration.GetSection("QueueConfig:OrderTopicName").Get<string>()!)
        .WithQueueName(builder.Configuration.GetSection("QueueConfig:OrderQueueName").Get<string>()!)); // Doesn't respect error queue
});

Setup the subscription to the topic for the message OrderCreatedEvent and add the topic name and queue name. Additionally configure the queue URI.

Expected behaviour
I would expect the library to know when providing the QueueName and topic name to load the existing queue and know it has a DLQ already.

Actual behaviour
Instead the library cretes a new DLQ and updated the queues DLQ.

System information:

• OS: Windows 11/AWS
• Library Version: 7.1.2
• .NET version: 8.0.303

Additional context
N/A

[jjnrmason]

I can see that there is 2 different paths. WithQueueUri uses the QueueAddressSubscriptionBuilder and won't check for anything existing and ForTopic uses the TopicSubscriptionBuilder which does check.

TopicSubscriptionBuilder will always try to create the error queue because it'll check for sourceQueueName + "_error" (ErrorQueue).

I wonder if it'd be sensible to add WithQueueUri to the TopicSubscriptionBuilder