Fix index misalignment in MultiLingualObjectManager bulk fallback

framework/src/Volo.Abp.MultiLingualObjects/Volo/Abp/MultiLingualObjects/MultiLingualObjectManager.cs

@@ -152,26 +152,11 @@ public class MultiLingualObjectManager : IMultiLingualObjectManager, ITransientD
             var index = 0;
             foreach (var translations in translationsCombined)
             {
-                if (!translations.Any())
+                //if the src has no translations, don't try to find a translation
-                {
+                if (translations.Any() && res[index] == null)
-                    //don't try to find a translation
-                }
-                else
                 {
-                    var translation = res[index];
+                    res[index] = translations.FirstOrDefault(pt => pt.Language == defaultLanguage) ??
-                    if (translation != null)
+                                 translations.FirstOrDefault();
-                    {
-                        continue;
-                    }
-                    translation = translations.FirstOrDefault(pt => pt.Language == defaultLanguage);
-                    if (translation != null)
-                    {
-                        res[index] = translation;
-                    }
-                    else
-                    {
-                        res[index] = translations.FirstOrDefault();
-                    }
                 }
                 index++;
             }

framework/test/Volo.Abp.LuckyPenny.AutoMapper.Tests/Volo/Abp/MultiLingualObjects/MultiLingualObjectManager_Tests.cs

@@ -107,14 +107,20 @@ public class MultiLingualObjectManager_Tests : AbpIntegratedTest<AbpLuckyPennyMu
             var translations = await _multiLingualObjectManager.GetBulkTranslationsAsync<MultiLingualBook, MultiLingualBookTranslation>(_books);
             foreach (var (entity, translation) in translations)
             {
-                if (entity.Translations.Any(x => x.Language == "en"))
+                if (!entity.Translations.Any())
+                {
+                    translation.ShouldBeNull();
+                }
+                else if (entity.Translations.Any(x => x.Language == "en"))
                 {
                     translation.ShouldNotBeNull();
                     translation.Name.ShouldBe(_testTranslations["en"]);
                 }
                 else
                 {
-                    translation.ShouldBeNull();
+                    //Falls back to the default language or the first available translation
+                    translation.ShouldNotBeNull();
+                    entity.Translations.ShouldContain(translation);
                 }
             }
         }
@@ -126,10 +132,12 @@ public class MultiLingualObjectManager_Tests : AbpIntegratedTest<AbpLuckyPennyMu
         using (CultureHelper.Use("en-us"))
         {
             var translations = await _multiLingualObjectManager.GetBulkTranslationsAsync(_books.Select(x => x.Translations));
-            foreach (var translation in translations)
+            translations.Count.ShouldBe(_books.Count);
-            {
+            translations[0].ShouldBeNull();
-                translation?.Name.ShouldBe(_testTranslations["en"]);
+            translations[1]!.Name.ShouldBe(_testTranslations["en"]);
-            }
+            translations[2]!.Name.ShouldBe(_testTranslations["ar"]);
+            translations[3]!.Name.ShouldBe(_testTranslations["en"]);
+            translations[4]!.Name.ShouldBe(_testTranslations["en"]);
         }
     }
 
@@ -149,7 +157,9 @@ public class MultiLingualObjectManager_Tests : AbpIntegratedTest<AbpLuckyPennyMu
             {
                 var og = _books[i];
                 var m = mapped[i];
-                Assert.Equal(og.Translations.FirstOrDefault(x => x.Language == "en")?.Name, m.Name);
+                var expectedName = og.Translations.FirstOrDefault(x => x.Language == "en")?.Name ??
+                                   og.Translations.FirstOrDefault()?.Name;
+                Assert.Equal(expectedName, m.Name);
             }
         }
     }

framework/test/Volo.Abp.MultiLingualObjects.Tests/Volo/Abp/MultiLingualObjects/MultiLingualObjectManager_Tests.cs

@@ -108,14 +108,20 @@ public class MultiLingualObjectManager_Tests : AbpIntegratedTest<AbpMultiLingual
             var translations = await _multiLingualObjectManager.GetBulkTranslationsAsync<MultiLingualBook, MultiLingualBookTranslation>(_books);
             foreach (var (entity, translation) in translations)
             {
-                if (entity.Translations.Any(x => x.Language == "en"))
+                if (!entity.Translations.Any())
+                {
+                    translation.ShouldBeNull();
+                }
+                else if (entity.Translations.Any(x => x.Language == "en"))
                 {
                     translation.ShouldNotBeNull();
                     translation.Name.ShouldBe(_testTranslations["en"]);
                 }
                 else
                 {
-                    translation.ShouldBeNull();
+                    //Falls back to the default language or the first available translation
+                    translation.ShouldNotBeNull();
+                    entity.Translations.ShouldContain(translation);
                 }
             }
         }
@@ -127,10 +133,58 @@ public class MultiLingualObjectManager_Tests : AbpIntegratedTest<AbpMultiLingual
         using (CultureHelper.Use("en-us"))
         {
             var translations = await _multiLingualObjectManager.GetBulkTranslationsAsync(_books.Select(x => x.Translations));
-            foreach (var translation in translations)
+            translations.Count.ShouldBe(_books.Count);
+            translations[0].ShouldBeNull();
+            translations[1]!.Name.ShouldBe(_testTranslations["en"]);
+            translations[2]!.Name.ShouldBe(_testTranslations["ar"]);
+            translations[3]!.Name.ShouldBe(_testTranslations["en"]);
+            translations[4]!.Name.ShouldBe(_testTranslations["en"]);
+        }
+    }
+
+    [Fact]
+    public async Task GetBulkTranslationsAsync_Should_Keep_Translations_Aligned_With_Entities()
+    {
+        using (CultureHelper.Use("en-us"))
+        {
+            var books = new List<MultiLingualBook>
             {
-                translation?.Name.ShouldBe(_testTranslations["en"]);
+                //resolved in the first pass
-            }
+                GetTestBook("en"),
+                //has no translations
+                GetTestBook(),
+                //resolved by the fallback pass
+                GetTestBook("ar")
+            };
+
+            var translations = await _multiLingualObjectManager.GetBulkTranslationsAsync<MultiLingualBook, MultiLingualBookTranslation>(books);
+
+            translations.Count.ShouldBe(3);
+            translations[0].entity.ShouldBe(books[0]);
+            translations[0].translation.ShouldNotBeNull();
+            translations[0].translation!.Name.ShouldBe(_testTranslations["en"]);
+            translations[1].entity.ShouldBe(books[1]);
+            translations[1].translation.ShouldBeNull();
+            translations[2].entity.ShouldBe(books[2]);
+            translations[2].translation.ShouldNotBeNull();
+            translations[2].translation!.Name.ShouldBe(_testTranslations["ar"]);
+        }
+    }
+
+    [Fact]
+    public async Task GetBulkTranslationsAsync_Should_Prefer_Default_Language_Over_First_Translation()
+    {
+        using (CultureHelper.Use("fr-FR"))
+        {
+            var books = new List<MultiLingualBook>
+            {
+                GetTestBook("ar", "en")
+            };
+
+            var translations = await _multiLingualObjectManager.GetBulkTranslationsAsync<MultiLingualBook, MultiLingualBookTranslation>(books);
+
+            translations[0].translation.ShouldNotBeNull();
+            translations[0].translation!.Name.ShouldBe(_testTranslations["en"]);
         }
     }
 
@@ -150,7 +204,9 @@ public class MultiLingualObjectManager_Tests : AbpIntegratedTest<AbpMultiLingual
             {
                 var og = _books[i];
                 var m = mapped[i];
-                Assert.Equal(og.Translations.FirstOrDefault(x => x.Language == "en")?.Name, m.Name);
+                var expectedName = og.Translations.FirstOrDefault(x => x.Language == "en")?.Name ??
+                                   og.Translations.FirstOrDefault()?.Name;
+                Assert.Equal(expectedName, m.Name);
             }
         }
     }