Rendering: Explicitly contextualize variation context for language fallback (closes #20350)

src/Umbraco.Core/Models/PublishedContent/PublishedValueFallback.cs

@@ -1,4 +1,4 @@
 using Microsoft.Extensions.DependencyInjection;
 using Umbraco.Cms.Core.DependencyInjection;
 using Umbraco.Cms.Core.Services;
 using Umbraco.Cms.Core.Services.Navigation;
@@ -317,7 +317,7 @@
             }
 
             var culture2 = language2.IsoCode;
-            T? culture2Value = getValue(culture2, segment);
+            T? culture2Value = TryGetExplicitlyContextualizedValue(getValue, culture2, segment);
             if (culture2Value != null)
             {
                 value = culture2Value;
@@ -329,6 +329,26 @@
     }
 
     private bool TryGetValueWithDefaultLanguageFallback<T>(IPublishedProperty property, string? culture, string? segment, out T? value)
+        => TryGetValueWithDefaultLanguageFallback(
+            (actualCulture, actualSegment)
+                => property.HasValue(actualCulture, actualSegment)
+                    ? property.Value<T>(this, actualCulture, actualSegment)
+                    : default,
+            culture,
+            segment,
+            out value);
+
+    private bool TryGetValueWithDefaultLanguageFallback<T>(IPublishedElement element, string alias, string? culture, string? segment, out T? value)
+        => TryGetValueWithDefaultLanguageFallback(
+            (actualCulture, actualSegment)
+                => element.HasValue(alias, actualCulture, actualSegment)
+                    ? element.Value<T>(this, alias, actualCulture, actualSegment)
+                    : default,
+            culture,
+            segment,
+            out value);
+
+    private bool TryGetValueWithDefaultLanguageFallback<T>(TryGetValueForCultureAndSegment<T> getValue, string? culture, string? segment, out T? value)
     {
         value = default;
 
@@ -337,33 +357,39 @@
             return false;
         }
 
-        string? defaultCulture = _localizationService?.GetDefaultLanguageIsoCode();
-        if (culture.InvariantEquals(defaultCulture) == false && property.HasValue(defaultCulture, segment))
+        var defaultCulture = _localizationService?.GetDefaultLanguageIsoCode();
+        if (defaultCulture.IsNullOrWhiteSpace())
         {
-            value = property.Value<T>(this, defaultCulture, segment);
-            return true;
+            return false;
         }
 
-        return false;
-    }
-
-    private bool TryGetValueWithDefaultLanguageFallback<T>(IPublishedElement element, string alias, string? culture, string? segment, out T? value)
-    {
-        value = default;
-
-        if (culture.IsNullOrWhiteSpace())
+        if (culture.InvariantEquals(defaultCulture))
         {
             return false;
         }
 
-        string? defaultCulture = _localizationService?.GetDefaultLanguageIsoCode();
-        if (culture.InvariantEquals(defaultCulture) == false && element.HasValue(alias, defaultCulture, segment))
+        T? fallbackValue = TryGetExplicitlyContextualizedValue(getValue, defaultCulture, segment);
+        if (fallbackValue == null)
         {
-            value = element.Value<T>(this, alias, defaultCulture, segment);
-            return true;
+            return false;
         }
 
-        return false;
+        value = fallbackValue;
+        return true;
+    }
+
+    private T? TryGetExplicitlyContextualizedValue<T>(TryGetValueForCultureAndSegment<T> getValue, string culture, string? segment)
+    {
+        VariationContext? current = _variationContextAccessor.VariationContext;
+        try
+        {
+            _variationContextAccessor.VariationContext = new VariationContext(culture, segment);
+            return getValue(culture, segment);
+        }
+        finally
+        {
+            _variationContextAccessor.VariationContext = current;
+        }
     }
 
     private delegate T? TryGetValueForCultureAndSegment<out T>(string actualCulture, string? actualSegment);

tests/Umbraco.Tests.Integration/Umbraco.Core/PublishedContent/PublishedContentFallbackTests.cs

@@ -1,4 +1,4 @@
 using Microsoft.AspNetCore.Http;
 using NUnit.Framework;
 using Umbraco.Cms.Core;
 using Umbraco.Cms.Core.Cache;
@@ -35,6 +35,8 @@
 
     private IApiContentBuilder ApiContentBuilder => GetRequiredService<IApiContentBuilder>();
 
+    private ILanguageService LanguageService => GetRequiredService<ILanguageService>();
+
     protected override void CustomTestSetup(IUmbracoBuilder builder)
         => builder
             .AddUmbracoHybridCache()
@@ -98,6 +100,36 @@
         Assert.AreEqual(invariantTitle, invariantValue);
     }
 
+    [TestCase("Danish title", true)]
+    [TestCase("Danish title", false)]
+    [TestCase(null, true)]
+    [TestCase(null, false)]
+    public async Task Property_Value_Can_Perform_Explicit_Language_Fallback(string? danishTitle, bool performFallbackToDefaultLanguage)
+    {
+        var danishLanguage = new Language("da-DK", "Danish")
+        {
+            FallbackIsoCode = "en-US"
+        };
+        await LanguageService.CreateAsync(danishLanguage, Constants.Security.SuperUserKey);
+
+        UmbracoContextFactory.EnsureUmbracoContext();
+
+        const string englishTitle = "English title";
+        var publishedContent = await SetupCultureVariantContentAsync(englishTitle, danishTitle);
+
+        VariationContextAccessor.VariationContext = new VariationContext(culture: "da-DK", segment: null);
+        var danishValue = publishedContent.Value<string>(PublishedValueFallback, "title");
+        Assert.AreEqual(danishTitle ?? string.Empty, danishValue);
+
+        var fallback = performFallbackToDefaultLanguage ? Fallback.ToDefaultLanguage : Fallback.ToLanguage;
+        var fallbackValue = publishedContent.Value<string>(PublishedValueFallback, "title", fallback: fallback);
+        Assert.AreEqual(danishTitle ?? englishTitle, fallbackValue);
+
+        VariationContextAccessor.VariationContext = new VariationContext(culture: "en-US", segment: null);
+        var englishValue = publishedContent.Value<string>(PublishedValueFallback, "title");
+        Assert.AreEqual(englishTitle, englishValue);
+    }
+
     private async Task<IPublishedContent> SetupSegmentedContentAsync(string? invariantTitle, string? segmentedTitle)
     {
         var contentType = new ContentTypeBuilder()
@@ -124,11 +156,47 @@
         ContentService.Save(content);
         ContentService.Publish(content, ["*"]);
 
+        return GetPublishedContent(content.Key);
+    }
+
+    private async Task<IPublishedContent> SetupCultureVariantContentAsync(string englishTitle, string? danishTitle)
+    {
+        var contentType = new ContentTypeBuilder()
+            .WithAlias("theContentType")
+            .WithContentVariation(ContentVariation.Culture)
+            .AddPropertyType()
+            .WithAlias("title")
+            .WithName("Title")
+            .WithDataTypeId(Constants.DataTypes.Textbox)
+            .WithPropertyEditorAlias(Constants.PropertyEditors.Aliases.TextBox)
+            .WithValueStorageType(ValueStorageType.Nvarchar)
+            .WithVariations(ContentVariation.Culture)
+            .Done()
+            .WithAllowAsRoot(true)
+            .Build();
+        await ContentTypeService.CreateAsync(contentType, Constants.Security.SuperUserKey);
+
+        var content = new ContentBuilder()
+            .WithContentType(contentType)
+            .WithCultureName("en-US", "EN")
+            .WithCultureName("da-DK", "DA")
+            .WithName("Content")
+            .Build();
+        content.SetValue("title", englishTitle, culture: "en-US");
+        content.SetValue("title", danishTitle, culture: "da-DK");
+        ContentService.Save(content);
+        ContentService.Publish(content, ["en-US", "da-DK"]);
+
+        return GetPublishedContent(content.Key);
+    }
+
+    private IPublishedContent GetPublishedContent(Guid key)
+    {
         ContentCacheRefresher.Refresh([new ContentCacheRefresher.JsonPayload { ChangeTypes = TreeChangeTypes.RefreshAll }]);
 
         UmbracoContextAccessor.Clear();
         var umbracoContext = UmbracoContextFactory.EnsureUmbracoContext().UmbracoContext;
-        var publishedContent = umbracoContext.Content.GetById(content.Key);
+        var publishedContent = umbracoContext.Content.GetById(key);
         Assert.IsNotNull(publishedContent);
 
         return publishedContent;

tests/Umbraco.Tests.Integration/Umbraco.Infrastructure/PropertyEditors/BlockListElementLevelVariationTests.Publishing.cs

@@ -1932,4 +1932,95 @@ void AssertPropertyValues(string culture, IContent expectedPickedContent)
             Assert.AreEqual(expectedPickedContent.Key, actualPickedPublishedContent.Key);
         }
     }
+
+    [TestCase(ContentVariation.Culture, false)]
+    [TestCase(ContentVariation.Culture, true)]
+    [TestCase(ContentVariation.Nothing, false)]
+    [TestCase(ContentVariation.Nothing, true)]
+    public async Task Can_Perform_Language_Fallback(ContentVariation elementTypeVariation, bool performFallbackToDefaultLanguage)
+    {
+        var daDkLanguage = await LanguageService.GetAsync("da-DK");
+        Assert.IsNotNull(daDkLanguage);
+        daDkLanguage.FallbackIsoCode = "en-US";
+        var saveLanguageResult = await LanguageService.UpdateAsync(daDkLanguage, Constants.Security.SuperUserKey);
+        Assert.IsTrue(saveLanguageResult.Success);
+
+        daDkLanguage = await LanguageService.GetAsync("da-DK");
+        Assert.AreEqual("en-US", daDkLanguage?.FallbackIsoCode);
+
+        var elementType = CreateElementType(elementTypeVariation);
+        var blockListDataType = await CreateBlockListDataType(elementType);
+        var contentType = CreateContentType(ContentVariation.Culture, blockListDataType, ContentVariation.Culture);
+
+        var content = CreateContent(
+            contentType,
+            elementType,
+            new []
+            {
+                new BlockProperty(
+                    new List<BlockPropertyValue>
+                    {
+                        new() { Alias = "invariantText", Value = "English invariantText content value" },
+                        new() { Alias = "variantText", Value = "English variantText content value" }
+                    },
+                    new List<BlockPropertyValue>
+                    {
+                        new() { Alias = "invariantText", Value = "English invariantText settings value" },
+                        new() { Alias = "variantText", Value = "English variantText settings value" }
+                    },
+                    "en-US",
+                    null)
+            },
+            true);
+
+        AssertPropertyValuesWithFallback("en-US",
+            "English invariantText content value", "English variantText content value",
+            "English invariantText settings value", "English variantText settings value");
+
+        AssetEmptyPropertyValues("da-DK");
+
+        AssertPropertyValuesWithFallback("da-DK",
+            "English invariantText content value", "English variantText content value",
+            "English invariantText settings value", "English variantText settings value");
+
+        void AssertPropertyValuesWithFallback(string culture,
+            string expectedInvariantContentValue, string expectedVariantContentValue,
+            string expectedInvariantSettingsValue, string expectedVariantSettingsValue)
+        {
+            SetVariationContext(culture, null);
+            var publishedContent = GetPublishedContent(content.Key);
+
+            var fallback = performFallbackToDefaultLanguage ? Fallback.ToDefaultLanguage : Fallback.ToLanguage;
+
+            var publishedValueFallback = GetRequiredService<IPublishedValueFallback>();
+            var value = publishedContent.Value<BlockListModel>(publishedValueFallback, "blocks", fallback: fallback);
+            Assert.IsNotNull(value);
+            Assert.AreEqual(1, value.Count);
+
+            var blockListItem = value.First();
+            Assert.AreEqual(2, blockListItem.Content.Properties.Count());
+            Assert.Multiple(() =>
+            {
+                Assert.AreEqual(expectedInvariantContentValue, blockListItem.Content.Value<string>("invariantText"));
+                Assert.AreEqual(expectedVariantContentValue, blockListItem.Content.Value<string>("variantText"));
+            });
+
+            Assert.AreEqual(2, blockListItem.Settings.Properties.Count());
+            Assert.Multiple(() =>
+            {
+                Assert.AreEqual(expectedInvariantSettingsValue, blockListItem.Settings.Value<string>("invariantText"));
+                Assert.AreEqual(expectedVariantSettingsValue, blockListItem.Settings.Value<string>("variantText"));
+            });
+        }
+
+        void AssetEmptyPropertyValues(string culture)
+        {
+            SetVariationContext(culture, null);
+            var publishedContent = GetPublishedContent(content.Key);
+
+            var value = publishedContent.Value<BlockListModel>("blocks");
+            Assert.NotNull(value);
+            Assert.IsEmpty(value);
+        }
+    }
 }