V8: Allow localization of the backoffice using parent cultures to the editor culture

src/Umbraco.Core/Persistence/Repositories/Implement/LanguageRepository.cs

@@ -250,7 +250,6 @@ public ILanguage GetByIsoCode(string isoCode)
             lock (_codeIdMap)
             {
                 if (_codeIdMap.TryGetValue(isoCode, out var id)) return id;
-                if (isoCode.Contains('-') && _codeIdMap.TryGetValue(isoCode.Split('-').First(), out var invariantId)) return invariantId;
             }
             if (throwOnNotFound)
                 throw new ArgumentException($"Code {isoCode} does not correspond to an existing language.", nameof(isoCode));

src/Umbraco.Tests/Persistence/Repositories/LanguageRepositoryTest.cs

@@ -79,39 +79,6 @@ public void Can_Perform_Get_By_Iso_Code_On_LanguageRepository()
             }
         }
 
-        [Test]
-        public void Can_Perform_Get_By_Invariant_Code_On_LanguageRepository()
-        {
-            var provider = TestObjects.GetScopeProvider(Logger);
-            using (var scope = provider.CreateScope())
-            {
-                var repository = CreateRepository(provider);
-
-                var es = new CultureInfo("es");
-                var esSpecific = new CultureInfo("es-ES");
-
-                var language = (ILanguage)new Language(es.Name)
-                {
-                    CultureName = es.DisplayName,
-                    FallbackLanguageId = 1
-                };
-                repository.Save(language);
-
-                language = repository.GetByIsoCode(es.Name);
-                var languageSpecific = repository.GetByIsoCode(esSpecific.Name);
-
-                // Assert
-                Assert.That(language, Is.Not.Null);
-                Assert.That(language.HasIdentity, Is.True);
-                Assert.That(language.IsoCode, Is.EqualTo(es.Name));
-
-                Assert.That(languageSpecific, Is.Not.Null);
-                Assert.That(languageSpecific.HasIdentity, Is.True);
-                Assert.That(languageSpecific.Id, Is.EqualTo(language.Id));
-                Assert.That(language.IsoCode, Is.EqualTo(language.IsoCode));
-            }
-        }
-
         [Test]
         public void Get_When_Id_Doesnt_Exist_Returns_Null()
         {

src/Umbraco.Web/Dictionary/UmbracoCultureDictionary.cs

@@ -122,7 +122,20 @@ private ILanguage Language
                 //ensure it's stored/retrieved from request cache
                 //NOTE: This is no longer necessary since these are cached at the runtime level, but we can leave it here for now.
                 return _requestCache.GetCacheItem<ILanguage>(typeof (DefaultCultureDictionary).Name + "Culture" + Culture.Name,
-                    () => _localizationService.GetLanguageByIsoCode(Culture.Name));
+                    () => {
+                        // find a language that matches the current culture or any of its parent cultures
+                        var culture = Culture;
+                        while(culture != CultureInfo.InvariantCulture)
+                        {
+                            var language = _localizationService.GetLanguageByIsoCode(culture.Name);
+                            if(language != null)
+                            {
+                                return language;
+                            }
+                            culture = culture.Parent;
+                        }
+                        return null;
+                    });
             }
         }
     }