Another minor fix.

backend/src/Squidex.Domain.Apps.Entities/Assets/State/AssetFolderState.cs

@@ -42,7 +42,7 @@ namespace Squidex.Domain.Apps.Entities.Assets.State
                         return true;
                     }
 
-                case AssetFolderRenamed e when Is.ChangeWhenDefined(FolderName, e.FolderName):
+                case AssetFolderRenamed e when Is.OptionalChange(FolderName, e.FolderName):
                     {
                         FolderName = e.FolderName;
 

backend/src/Squidex.Domain.Apps.Entities/Assets/State/AssetState.cs

@@ -86,6 +86,8 @@ namespace Squidex.Domain.Apps.Entities.Assets.State
 
                         TotalSize += e.FileSize;
 
+                        EnsureProperties();
+
                         return true;
                     }
 
@@ -95,6 +97,8 @@ namespace Squidex.Domain.Apps.Entities.Assets.State
 
                         TotalSize += e.FileSize;
 
+                        EnsureProperties();
+
                         return true;
                     }
 
@@ -102,34 +106,36 @@ namespace Squidex.Domain.Apps.Entities.Assets.State
                     {
                         var hasChanged = false;
 
-                        if (Is.ChangeWhenDefined(FileName, e.FileName))
+                        if (Is.OptionalChange(FileName, e.FileName))
                         {
                             FileName = e.FileName;
 
                             hasChanged = true;
                         }
 
-                        if (Is.ChangeWhenDefined(Slug, e.Slug))
+                        if (Is.OptionalChange(Slug, e.Slug))
                         {
                             Slug = e.Slug;
 
                             hasChanged = true;
                         }
 
-                        if (Is.Change(Tags, e.Tags))
+                        if (Is.OptionalChange(Tags, e.Tags))
                         {
                             Tags = e.Tags;
 
                             hasChanged = true;
                         }
 
-                        if (Is.Change(Metadata, e.Metadata))
+                        if (Is.OptionalChange(Metadata, e.Metadata))
                         {
                             Metadata = e.Metadata;
 
                             hasChanged = true;
                         }
 
+                        EnsureProperties();
+
                         return hasChanged;
                     }
 
@@ -150,5 +156,18 @@ namespace Squidex.Domain.Apps.Entities.Assets.State
 
             return false;
         }
+
+        private void EnsureProperties()
+        {
+            if (Tags == null)
+            {
+                Tags = new HashSet<string>();
+            }
+
+            if (Metadata == null)
+            {
+                Metadata = new AssetMetadata();
+            }
+        }
     }
 }

backend/src/Squidex.Infrastructure/Commands/Is.cs

@@ -18,24 +18,24 @@ namespace Squidex.Infrastructure.Commands
             return !Equals(oldValue, newValue);
         }
 
-        public static bool Change(string? oldValue, string newValue)
+        public static bool Change(string oldValue, string newValue)
         {
             return !Equals(oldValue, newValue);
         }
 
-        public static bool ChangeWhenDefined(string? oldValue, string? newValue)
+        public static bool OptionalChange(string oldValue, string? newValue)
         {
             return !string.IsNullOrWhiteSpace(newValue) && !string.Equals(oldValue, newValue);
         }
 
-        public static bool Change<T>(ISet<T>? oldValue, [NotNullWhen(true)] ISet<T>? newValue)
+        public static bool OptionalChange<T>(ISet<T> oldValue, [NotNullWhen(true)] ISet<T>? newValue)
         {
-            return newValue != null && (oldValue == null || !newValue.SetEquals(oldValue));
+            return newValue != null && !newValue.SetEquals(oldValue);
         }
 
-        public static bool Change<TKey, TValue>(IReadOnlyDictionary<TKey, TValue>? oldValue, [NotNullWhen(true)] IReadOnlyDictionary<TKey, TValue>? newValue) where TKey : notnull
+        public static bool OptionalChange<TKey, TValue>(IReadOnlyDictionary<TKey, TValue> oldValue, [NotNullWhen(true)] IReadOnlyDictionary<TKey, TValue>? newValue) where TKey : notnull
         {
-            return newValue != null && (oldValue == null || !newValue.EqualsDictionary(oldValue));
+            return newValue != null && !newValue.EqualsDictionary(oldValue);
         }
     }
 }