Bugfix exception during install, live models collision

src/Umbraco.Core/PublishedModelFactoryExtensions.cs

@@ -0,0 +1,33 @@
+using System;
+using Umbraco.Core.Models.PublishedContent;
+
+namespace Umbraco.Core
+{
+    /// <summary>
+    /// Provides extension methods for <see cref="IPublishedModelFactory"/>.
+    /// </summary>
+    public static class PublishedModelFactoryExtensions
+    {
+        /// <summary>
+        /// Executes an action with a safe live factory/
+        /// </summary>
+        /// <remarks>
+        /// <para>If the factory is a live factory, ensures it is refreshed and locked while executing the action.</para>
+        /// </remarks>
+        public static void WithSafeLiveFactory(this IPublishedModelFactory factory, Action action)
+        {
+            if (factory is ILivePublishedModelFactory liveFactory)
+            {
+                lock (liveFactory.SyncRoot)
+                {
+                    liveFactory.Refresh();
+                    action();
+                }
+            }
+            else
+            {
+                action();
+            }
+        }
+    }
+}