Fallback ToLanguage with BlockList Regression

[warrenbuckley]

Which Umbraco version are you using?

16.2.0

Bug summary

When rendering content in a view, the contents of a BlockList are unable to fallback to a Default Language

Specifics

We have checked away from our implementation and compared against latest 16 (16.2.0) and latest 13 (13.10.1) to ensure it was nothing specific with our content or code.

Steps to reproduce

Video

This is a video explaining the content/datatype structure setup along with it working in V13 but not in V16 with the same code.

Blocklist-Language-Fallback-Bug_ENCODED_720.mp4

Code to override Fallback Value used with ModelsBuilder

using Umbraco.Cms.Core.Models.PublishedContent;

namespace Umbraco.Cms.Web.Common.PublishedModels;

public static class PublishedContentExtensions
{
    private static IPublishedValueFallback PublishedValueFallback { get; } =
        StaticServiceProvider.Instance.GetRequiredService<IPublishedValueFallback>();

    public static T? Value<T>(
        this IPublishedElement content,
        IPublishedValueFallback publishedValueFallback,
        string alias,
        string? culture = null,
        string? segment = null,
        Fallback fallback = default)
    {
        return content.Value<T>(publishedValueFallback, alias, culture, segment, Fallback.ToLanguage, default);
    }

    public static T? Value<T>(
        this IPublishedContent content,
        string alias,
        string? culture = null,
        string? segment = null,
        Fallback fallback = default)
    {
        return content.Value<T>(PublishedValueFallback, alias, culture, segment, Fallback.ToLanguage, default);
    }

    public static T? Value<T>(
        this IPublishedContent content,
        string alias)
    {
        return content.Value<T>(PublishedValueFallback, alias, null, null, Fallback.ToLanguage, default);
    }
}

testpage.cshtml - Template

@using Umbraco.Cms.Web.Common.PublishedModels;
@inherits Umbraco.Cms.Web.Common.Views.UmbracoViewPage<TestPage>
@{
	Layout = null;
}

<h1>Static Content</h1>

<h2>Title .Value("alias") = @Model.Value("title", fallback: Fallback.ToLanguage)</h2>
<h2>Title Models Builder = @Model.Title</h2>
<h2>Title .ValueFor() = @Model.ValueFor(x => x.Title, fallback: Fallback.ToDefaultLanguage)</h2>

<hr/>

<h2>Block Grid</h2>
@Html.GetBlockListHtml(Model.BlockList)

Blocklist/Components/HeaderBlock - Block View Partial

@inherits Umbraco.Cms.Web.Common.Views.UmbracoViewPage<Umbraco.Cms.Core.Models.Blocks.BlockListItem>;
@using ContentModels = Umbraco.Cms.Web.Common.PublishedModels;
@{
    var content = (ContentModels.HeaderBlock)Model.Content;
}

<div style="border: solid red;margin-bottom: 10px;">

    <h2>I AM HeaderBlock Static</h2>

    <h3>Models = @content.HeaderTitle</h3>
    <h3>Value() @content.Value("headerTitle", fallback: Fallback.ToDefaultLanguage)</h3>
    <h3>ValueFor() @content.ValueFor(x=> x.HeaderTitle, fallback: Fallback.ToDefaultLanguage)</h3>

</div>

Expected result / actual result

That the BlockList and/or BlockGrid will fallback to the default language as before.

[AndyButland]

Can you share a bit more details of the setup and how you are rendering it your template please @warrenbuckley? You mention a video, but I don't see it linked.

[warrenbuckley]

@AndyButland looks like I hit the upload limit - trying to compress video or put it elsewhere....

I will update the original issue details above with the code used in template

[warrenbuckley]

Video & code from views/partials updated on the issue for you now Andy 😄

[AndyButland]

I still don't see the video but maybe there's enough to replicate. Could you just confirm how your block list various by culture? I.e. does the list itself vary, or is that shared and uses elements that have properties that vary by culture?

[warrenbuckley]

Any luck now?
https://github.com/user-attachments/assets/45ab81d1-0b58-464d-a87e-3e049e15eb53

[simonech]

I still don't see the video but maybe there's enough to replicate. Could you just confirm how your block list various by culture? I.e. does the list itself vary, or is that shared and uses elements that have properties that vary by culture?

Both setup have the same issue. With block level variants and with the full property as variant.

[simonech]

@AndyButland just to add a bit of context: that PublishedContentExtensions is because we wanted all generated models to have automatic fallback to the main language, and didn't want to update manually 100s of properties. But the behavior is also if we call the Model.Value() method directly.

[AndyButland]

I'm getting ambiguous method compilation errors when I try to add your extensions, but if you say you see the problem without that, perhaps let's not consider those for now to isolate a possible complication.

I've prepared a similar setup:

• Two languages
• One variant document type with a text string a blocks property that are both variant
• One element type with a text string
• Populated only the content on the English language but published both

Am rendering with:

@using Umbraco.Cms.Core.Models.Blocks
@using ContentModels = Umbraco.Cms.Web.Common.PublishedModels
@inherits Umbraco.Cms.Web.Common.Views.UmbracoViewPage<ContentModels.VariantBlockListTest>
@{
	Layout = null;
}

<h1>Variant Block List Test</h1>

<div>Text (default): @Model.Value("text")</div>
<div>Text (default with fallback): @Model.Value("text", fallback: Fallback.ToLanguage)</div>
<div>Text (models builder): @Model.Text</div>
<div>Text (English): @Model.Value("text", culture: "en-US")</div>
<div>Text (Italian): @Model.Value("text", culture: "it")</div>
<div>Text (Italian with fallback): @Model.Value("text", culture: "it", fallback: Fallback.ToLanguage)</div>

<h2>Blocks (default)</h2>

@Html.GetBlockListHtml(Model.Value<BlockListModel>("blocks"))

<h2>Blocks (default with fallback)</h2>

@Html.GetBlockListHtml(Model.Value<BlockListModel>("blocks", fallback: Fallback.ToLanguage))

<h2>Blocks (with models builder)</h2>

@Html.GetBlockListHtml(Model.Blocks)

<h2>Blocks (with models builder with fallback)</h2>

@Html.GetBlockListHtml(Model.Blocks)

<h2>Blocks (English)</h2>

@Html.GetBlockListHtml(Model.Value<BlockListModel>("blocks", culture: "en-US"))

<h2>Blocks (Italian)</h2>

@Html.GetBlockListHtml(Model.Value<BlockListModel>("blocks", culture: "it"))

<h2>Blocks (Italian with fallback)</h2>

@Html.GetBlockListHtml(Model.Value<BlockListModel>("blocks", culture: "it", fallback: Fallback.ToLanguage))

And I see what I expect.

For English:

For Italian:

Can you see there anything that looks wrong, or if there's another syntax I've missed that shows the problem you are seeing please?

[warrenbuckley]

Update

Hi @AndyButland it seems that the problem is when you use cultures mapped to a domain that this then becomes a problem.

Video Repro

FallbackToLanguageBugUpdate.mp4

[AndyButland]

Hmm... I didn't make it clear, but I was using domains above. But I must be missing something - will look further.

[warrenbuckley]

I can ZIP up the project and put it somewhere if that is of any help to you, if needed.

[AndyButland]

Why not, might be a good idea so I can spot the difference - thanks.

[warrenbuckley]

Dropped you a DM with it - lets see if you can see what's going on?!

[AndyButland]

Thanks - I can replicate with your project, and have at least found where the problem occurs.

It's going wrong here:

Umbraco-CMS/src/Umbraco.Infrastructure/PropertyEditors/ValueConverters/BlockPropertyValueCreatorBase.cs

Lines 146 to 160 in e5c942b

	// if case changes have been made to the content or element type variation since the content was published,
	// we need to align those changes for the exposed blocks.
	IEnumerable<BlockItemVariation> expose = _blockEditorVarianceHandler.AlignedExposeVarianceAsync(converted.BlockValue, owner, element).GetAwaiter().GetResult();
	var expectedBlockVariationCulture = owner.ContentType.VariesByCulture() && element.ContentType.VariesByCulture()
	? variationContext.Culture.NullOrWhiteSpaceAsNull()
	: null;
	var expectedBlockVariationSegment = owner.ContentType.VariesBySegment() && element.ContentType.VariesBySegment()
	? variationContext.Segment.NullOrWhiteSpaceAsNull()
	: null;
	if (expose.Any(v =>
	v.ContentKey == element.Key && v.Culture == expectedBlockVariationCulture &&
	v.Segment == expectedBlockVariationSegment) is false)
	{
	continue;
	}

The VariationContext being retrieved here isn't populated with the culture we want in the fallback scenario - i.e. en - it's still set to fr from the initialization from the domain. So it doesn't find anything and exits.

So it seems we shouldn't be relying on the VariationContext to determine what culture we are getting a value for.

This will be set based on the domain for the request, using the language that maps to the domain - so in this case fr.

But if we are looking for a fallback language, or - less likely in practice but more explicit, if we have requested a given culture by calling @Html.GetBlockListHtml(Model.Value<BlockListModel>("blockList", culture: "en")) - on a request with a variation context set to fr, we'll get the wrong culture here and hit the continue statement.