Using a blueprint with blocks already in them to create content duplicates the ID's of the blocks.

[MatsLimetta]

Which Umbraco version are you using?

13.8.1

Bug summary

When creating a new page from a blueprint (content template), where the blueprint already has pre-added blocks, the blocks in question seems to be getting the same contentUdi's stored in the database, while the actual content is different.

Specifics

First off, we have a blueprint that has predefined blocks in a blocklist property.
When creating a new page from said blueprint (I do it programmatically), everything seems to be working alright. I can update the new pages blocks without issue, and when looking at the page and getting the pages blocks from it's template, it is getting the correct information.

However, when I try to access a list of pages from the cache(Like GetDecendants() for example), and trying to show content from the blocks, I get the content from another block.
They are 2 different pages, but the GUID of the first blocklist element is the same & the content/text is the same in the new page.
When pulling the data from the DB, I can see that the content is different, but the contentUdi is the same:

Steps to reproduce

• Create a blueprint(content template) with a blocklist property and add a couple of blocks to the blueprint.
• Create a couple of pages from this blueprint programmatically.
• Update the blocks on the new pages with different data.
• Get a list of the new pages and watch how you're getting some seemingly random content when trying to get the blocklist content.

Expected result / actual result

Desired outcome: Get the blocks from the actual page when getting a list of pages from the cache.
What actually happens: We get seemingly random content shown when listing the pages and trying to display their blockcontent.

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This item has been added to our backlog AB#53350

[github-actions]

Hi there @MatsLimetta!

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

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[AndyButland]

Possibly related to #18618 (though this was a 14+ issue).

[AndyButland]

As noted, the above was a 14+ issue and having looked a bit further, I can see this should have been resolved for 13 in #15541.

I'm thinking you must be seeing the problem due to one point where you said about creating a new page from said blueprint:

I do it programmatically

So that might be why you aren't getting the behaviour that ensures these IDs are recreated uniquely when a new content item is created from a blueprint.

If you look how in Umbraco itself we publish a notification having created an IContent from a blueprint:

Umbraco-CMS/src/Umbraco.Web.BackOffice/Controllers/ContentController.cs

Line 686 in 8433b2b

public ActionResult<ContentItemDisplay?> GetEmptyBlueprint(int blueprintId, int parentId)

You likely want to be doing similar. By publishing that notification, the same logic as runs in Umbraco to ensure unique IDs will run on the content item you have created yourself.

I'll close this as I believe following this through I've identified what's causing your issue and how you can resolve it, but please feel free to re-open if you feel I've missed something.

[MatsLimetta]

@AndyButland I'm trying to figure this out. Please bear with me :)

Is it the DeepClone() I'm missing?

When I'm doing this, I'm doing this:
var courseBlueprint = _contentService.GetBlueprintById(_syncConfig.CourseBlueprintId);
newCoursePage = _contentService.CreateContentFromBlueprint(courseBlueprint, course.CourseName);
(Removed some logging and nullchecks)

But what I would need to do, is create a DeepClone() of the blueprint, and then cast that back to an IContent?
Shouldn't that be done in the CreateContentFromBlueprint() if it's needed?

Edit: Oh, I thought this was just fixed in 15.4... But it seems if I dig deeper there is a fix for V13 too?

[AndyButland]

The main thing I wanted to get across was that in core, after scaffolding a new content item from a blueprint we publish a ContentScaffoldedNotification (line 702 if you follow the link above). That has a notification handler that will ensure the IDs for each block are unique and avoid the cache issues you've experienced.

My guess was that you weren't doing that when you are creating the content programatically from a blueprint - and you would need to do so. If you do that, or something similar to ensure the element IDs are all unique, then that should resolve the issue.

But I see what you mean - CreateContentFromBlueprint should arguably be doing this already. As such I'll re-open.

[MatsLimetta]

Ah ok, so it's the actual notification that ensures the unique ID's of the element. So if I were to do this:

var courseBlueprint = _contentService.GetBlueprintById(_syncConfig.CourseBlueprintId);
var deepCloneBp = (IContent)courseBlueprint.DeepClone();
deepCloneBp.Id = 0;
deepCloneBp.ParentId = parentId;
var scaffoldedNotification = new ContentScaffoldedNotification(courseBlueprint, deepCloneBp, parentId, new EventMessages());

newCoursePage = _contentService.CreateContentFromBlueprint(deepCloneBp, course.CourseName);

That would make sure the blocks are all getting new unique ID's, correct?

And thanks for reopening <3
It would be great if this could just be handled in CreateContentFromBlueprint without all the extra lines of code :)

[AndyButland]

Yes, I believe that should do it.

To be honest CreateContentFromBlueprint is confusing me. As far as I can tell we only call this in core when creating a "blueprint from content", so at the very least it's naming seems a little off.

[AndyButland]

Adding a bit of further context and summarising for further investigation.

The core issue here is that when a content item containing block elements is copied, it's important that the GUIDs for the element keys are regenerated so that they are unique. Without that we get cached data errors, as the elements are cached by ID and we can then get the wrong one returned for a given content item.

This is an example: #18618

We have a solution for this in BlockEditorPropertyNotificationHandlerBase and it's base class ComplexPropertyEditorContentNotificationHandler, which is run on copying and scaffolding content from a blueprint.

The problem is that this isn't called when using IContentService.CreateContentFromBlueprint.

We only call that in core when we are creating a blueprint from an existing content item. So that's actually OK. We don't particularly care that a given blueprint has the same element keys as an existing content item. Only that when we create a new content item from the blueprint, we get new IDs generated there.

But nothing is to stop someone programatically calling this method, as per this issue. And if they do that, they'll get duplicate element keys.

I'd suggest we tackle a fix for this on 16 first and, depending on how extensive that is, consider backporting to 13 after that. It could be we leave it for 13 as there has been quite a bit of change at the service level, and there is a workaround for this issue noted above.

Suggested approach:

• Verify the issue by creating content from a blueprint that contains a block list with at least one populated block programatically (you can look in umbracoPropertyData to see the saved JSON and check the keys are the same).
• See if its feasible to write a failing integration test for the issue.
• Consider if IContentService.CreateContentFromBlueprint should publish a ContentScaffoldedNotification? That seems semantically valid - i.e. we are "scaffolding" a new content item here.
• Verify if that resolves the issue (and the integration test passes).
• Maybe look at the naming of this method. It's a little confusing as it's called CreateContentFromBlueprint but we only call this in core when creating a "blueprint from content". Perhaps we should have an explicit CreateBlueprintFromContent (even if the implementation is in fact shared), with appropriate XML comments.