Fix availability and names

src/Umbraco.Core/Models/Content.cs

@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Reflection;
 using System.Runtime.Serialization;
+using Umbraco.Core.Exceptions;
 
 namespace Umbraco.Core.Models
 {
@@ -213,7 +214,10 @@ namespace Umbraco.Core.Models
         // sets a publish name
         // internal for repositories
         internal void SetPublishName(int? languageId, string name)
-        {
+        {
+            if (string.IsNullOrWhiteSpace(name))
+                throw new ArgumentNullOrEmptyException(nameof(name));
+
             if (languageId == null)
             {
                 PublishName = name;
@@ -412,8 +416,9 @@ namespace Umbraco.Core.Models
 
             // copy names
             ClearNames();
-            foreach (var (languageId, name) in other.Names)
+            foreach (var (languageId, name) in other.Names)
                 SetName(languageId, name);
+            Name = other.Name;
         }
 
         /// <inheritdoc />

src/Umbraco.Core/Models/ContentBase.cs

@@ -136,6 +136,12 @@ namespace Umbraco.Core.Models
         /// <inheritdoc />
         public virtual void SetName(int? languageId, string name)
         {
+            if (string.IsNullOrWhiteSpace(name))
+            {
+                ClearName(languageId);
+                return;
+            }
+
             if (languageId == null)
             {
                 Name = name;
@@ -152,6 +158,20 @@ namespace Umbraco.Core.Models
             OnPropertyChanged(Ps.Value.NamesSelector);
         }
 
+        private void ClearName(int? languageId)
+        {
+            if (languageId == null)
+            {
+                Name = null;
+                return;
+            }
+
+            if (_names == null) return;
+            _names.Remove(languageId.Value);
+            if (_names.Count == 0)
+                _names = null;
+        }
+
         protected virtual void ClearNames()
         {
             _names = null;