title: Terraform Topic resource already exists in across projects? How to handle this?
body: <p>How to deal with resources existing in multiple projects. In this case I have 2 TF projects and have a shared topic in google pubsub. Following the <a href="https://www.terraform.io/docs/providers/google/r/pubsub_subscription.html" rel="nofollow noreferrer">google provider docs</a> I created this configuration in the subscriber project. But it gives me a resource already exists error.</p>
  
  <pre><code>resource "google_pubsub_topic" "item_edited" {
    project = "listing-dev"
    name    = "item_edited"
  }
  </code></pre>
  
  <p>So this resource already exits in some other project but following the guides I created it our own project as well.</p>
  
  <pre><code>resource "google_pubsub_subscription" "item_edited" {
    name    = "item_edited_subscription"
    topic   = "${google_pubsub_topic.item_edited.id}"
    project = "${module.offer-dev.gcp_project_id}"
  }
  </code></pre>
  
  <p>Error:</p>
  
  <pre><code>Error: Error applying plan:
  
  1 error(s) occurred:
  
  * google_pubsub_topic.item_edited: 1 error(s) occurred:
  
  * google_pubsub_topic.item_edited: googleapi: Error 409: Resource already exists in the project (resource=item_edited)., alreadyExists
  </code></pre>