Handle user id 0 (Unknown/System) when building content version response

[lauraneto]

Prerequisites

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

This relates to issue #17149, as it was also being caused by having entries with user id 0.

Description

Details regarding the initial issue and how to test can be found in PR #19263.
In this case, instead of just opening the info tab, you will need to open the Rollback section.

The following code can be used to perform a publish with user id 0.

[Route("api/test")]
public class TestController : ControllerBase
{
    private readonly IContentService _contentService;

    public TestController(IContentService contentService)
    {
        _contentService = contentService;
    }

    [HttpGet("")]
    public IActionResult Get()
    {
        // Replace the GUID with the id of the content you created to test
        IContent content = _contentService.GetById(Guid.Parse("efd8a078-14d8-47f7-b22c-52d34944b6b0")) ?? throw new InvalidOperationException();
        _contentService.Save(content, 0);
        _contentService.Publish(content, ["*"], 0);

        return Ok();
    }
}

Before the fix

After the fix

[Copilot]

Pull Request Overview

This PR updates the document version response factory to correctly handle system/unknown users (ID 0) when building the API model.

• Refactors CreateAsync from an expression-bodied method to a block body
• Adds a switch to return an empty ReferenceByIdModel for Constants.Security.UnknownUserId
• Cleans up formatting around entity key resolution calls

Comments suppressed due to low confidence (2)

src/Umbraco.Cms.Api.Management/Factories/DocumentVersionPresentationFactory.cs:33

• Avoid using .Result inside an async method as it can block threads; consider awaiting the asynchronous GetKey call directly, e.g. await _entityService.GetKey(...).

new ReferenceByIdModel(_entityService.GetKey(contentVersion.ContentId, UmbracoObjectTypes.Document).Result),

src/Umbraco.Cms.Api.Management/Factories/DocumentVersionPresentationFactory.cs:27

• Add a unit test to cover the UnknownUserId branch in CreateAsync to verify that an empty ReferenceByIdModel is returned when contentVersion.UserId is 0.

Constants.Security.UnknownUserId => new ReferenceByIdModel(),

[Zeegaan]

Looks good, tests good ✔️