Relations: Allow Element and ElementContainer as allowed object types for relation creation

[ronaldbarendse]

Prerequisites

• I have added steps to test this contribution in the description below

If there's an existing issue for this PR then this fixes #23216

Description

v18 seeds three built-in element relation types (parent/child object types Element / ElementContainer) directly into the database via DatabaseDataCreator (install) and the V_18_0_0.AddElements migration (upgrade), bypassing IRelationService. But RelationService.SaveAsync validates object types against GetAllowedObjectTypes(), which never had Element/ElementContainer added. As a result the service rejects any CreateAsync/UpdateAsync of these relation types with InvalidParentObjectType/InvalidChildObjectType — breaking the backoffice Relations list and Umbraco Deploy import/transfer (which re-saves built-in relation types through the service).

This adds Element and ElementContainer to GetAllowedObjectTypes().

How to test:

1. On a clean 18.0.0 install, resolve IRelationService, load relateParentElementContainerOnElementDelete via GetRelationTypeByAlias, and call UpdateAsync — it now returns RelationTypeOperationStatus.Success (previously InvalidParentObjectType).
2. Or run the added integration tests: Can_Create_Relation_Types_With_Allowed_Object_Types now covers ElementContainer→Element and ElementContainer→ElementContainer.

Changes:

• src/Umbraco.Core/Services/RelationService.cs — add UmbracoObjectTypes.Element and UmbracoObjectTypes.ElementContainer to the allowed set.
• tests/Umbraco.Tests.Integration/.../RelationServiceTests.cs — two new test cases.

[claude]

Claude finished @ronaldbarendse's task in 2m 45s —— View job

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PR Review

Target: origin/main · Based on commit: 1d4d3842

Adds UmbracoObjectTypes.Element and UmbracoObjectTypes.ElementContainer to RelationService.GetAllowedObjectTypes(), allowing v18's seeded element relation types (relateParentElementContainerOnElementDelete, relateParentElementContainerOnContainerDelete) to be saved through IRelationService without returning InvalidParentObjectType/InvalidChildObjectType.

• Other changes: The ObjectTypePresentationFactory consumer of GetAllowedObjectTypes() will now also include Element and ElementContainer in the object-type picker response returned to the backoffice — this is the intended behavior and correctly aligns with what the migration seeds directly into the database.

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No Critical or Important issues found. No breaking changes — the change is purely additive.

Suggestions

• tests/.../RelationServiceTests.cs:52-53: Both new test cases cover the child–parent direction used by the two seeded relation types. Adding a case with Element as parent (e.g. Element → Element) would widen coverage slightly, but it is not required for correctness and the existing cases are sufficient to validate the fix.

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Approved

The fix is minimal, targeted, and correct. The two new integration test cases directly mirror the seeded relation types introduced in V_18_0_0/AddElements.cs, which is exactly the right regression harness. Good to merge.

[Copilot]

Pull request overview

This PR fixes a validation gap in IRelationService by allowing the new v18 element object types (Element, ElementContainer) to be used when creating/updating relation types via RelationService, aligning service validation with the relation types seeded by install/migrations.

Changes:

• Extend RelationService.GetAllowedObjectTypes() to include UmbracoObjectTypes.Element and UmbracoObjectTypes.ElementContainer.
• Expand integration test coverage to assert relation types can be created with ElementContainer → Element and ElementContainer → ElementContainer object type combinations.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
src/Umbraco.Core/Services/RelationService.cs	Adds Element/ElementContainer to the allowed object type set used by relation type validation.
tests/Umbraco.Tests.Integration/Umbraco.Core/Services/RelationServiceTests.cs	Adds two integration test cases covering the newly-allowed element relation type combinations.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[AndyButland]

Thanks @ronaldbarendse, looks good and a clear oversight/fix.

I'll label this for 18.1 for now, as it'll definitely be in that, but likely bring forward to 18.0.1 if and when we arrange a patch release.