Cannot assign domain to new content item after deleting ancestor of old content with same domain

[D-Inventor]

Which Umbraco version are you using?

16.3.3

Bug summary

When I delete an ancestor of content with a domain assigned to it, I cannot add that same domain to a different content item. I receive an error that says that the domain is used by another content item, even though that content item is deleted, along with its ancestors.

Specifics

This error happens in the backoffice, but also when using the Management API from an external integration. In my specific case, I create content scenario's for acceptance testing, in which I delete all content in the content tree and recreate it to ensure consistent state. I get an HTTP 409 response with a message that the domain is used, even though the content was just deleted. I can recreate this error in the backoffice with simple content editing:

After restarting the website, I am able to assign the domain, so it seems that this issue is related to a stale in-memory cache somewhere.

Steps to reproduce

1. Create one or more content types in the backoffice. Ensure that you can create a content tree with at least one root node and one child node
2. Create a content tree with one root node and one child node
3. Assign a domain to the child node, for example "localhost:44376"
4. Throw the root node (the one that DOES NOT have the domain assigned) into the trashcan
5. Empty the trashcan
6. Recreate the content tree
7. Attempt to assign the same domain to the new child node
8. Observe the error message

Expected result / actual result

I expect, when a node with an assigned domain is deleted, I can assign the domain to a new content item. Instead, I receive an error message that I cannot assign the domain, even though I should.

[github-actions]

Hi there @D-Inventor!

Firstly, a big thank you for raising this issue. Every piece of feedback we receive helps us to make Umbraco better.

We really appreciate your patience while we wait for our team to have a look at this but we wanted to let you know that we see this and share with you the plan for what comes next.

• We'll assess whether this issue relates to something that has already been fixed in a later version of the release that it has been raised for.
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• We'll replicate the issue to ensure that the problem is as described.
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We wish we could work with everyone directly and assess your issue immediately but we're in the fortunate position of having lots of contributions to work with and only a few humans who are able to do it. We are making progress though and in the meantime, we will keep you in the loop and let you know when we have any questions.

Thanks, from your friendly Umbraco GitHub bot 🤖 🙂

[AndyButland]

I can reproduce, but unfortunately having investigated for a while this morning I can't come up with a good solution to fix.

Will share some debugging notes.

The problem lies in ContentCacheRefresher.Refresh, where we get the ID of the deleted node, look up any domains that we previously had based on that node, and, if found, clear the domain cache.

For this situation though we have the ID of the root item being deleted, not the child item that has the domain associated. Hence nothing is found, and the cache isn't cleared.

The solution sounds clear enough - find the descendant IDs of the deleted node and use those to check for domains as well.

But the problem is that at this point, in a cache refresher, we don't seem to be able to still query for the descendants (have tried with IEntityService, IDocumentNavigationService and also by implementing a GetOfType on IAppCache that we call before the request to ClearOfType), as they are already deleted from the database and the relevant caches are already updated.