Run the same cleanup with scaffolding content as when copying. (#15541)

* Run the same cleanup with scaffolding content as when copying.

- Added a new ContentScaffoldedNotification
- Published the notification when a new scaffold has been created from a blueprint (content template)
- Linked up the ComplextPEContent handler to do the same cleanup for the new notification as when copying.
- registered handlers to the event for blocklist, blockgrid and nested content

* PR pattern matching suggestion

Co-authored-by: Nikolaj Geisle <70372949+Zeegaan@users.noreply.github.com>

---------

Co-authored-by: Sven Geusens <sge@umbraco.dk>
Co-authored-by: Nikolaj Geisle <70372949+Zeegaan@users.noreply.github.com>

src/Umbraco.Core/Notifications/ContentScaffoldedNotification.cs

@@ -0,0 +1,18 @@
+// Copyright (c) Umbraco.
+// See LICENSE for more details.
+
+using Umbraco.Cms.Core.Events;
+using Umbraco.Cms.Core.Models;
+
+namespace Umbraco.Cms.Core.Notifications;
+
+/// <summary>
+/// Notification that is send out when a Content item has been scaffolded from an original item and basic cleaning has been performed
+/// </summary>
+public sealed class ContentScaffoldedNotification : ScaffoldedNotification<IContent>
+{
+    public ContentScaffoldedNotification(IContent original, IContent scaffold, int parentId, EventMessages messages)
+        : base(original, scaffold, parentId, messages)
+    {
+    }
+}

src/Umbraco.Core/Notifications/ScaffoldedNotification.cs

@@ -0,0 +1,23 @@
+// Copyright (c) Umbraco.
+// See LICENSE for more details.
+
+using Umbraco.Cms.Core.Events;
+
+namespace Umbraco.Cms.Core.Notifications;
+
+public abstract class ScaffoldedNotification<T> : CancelableObjectNotification<T>
+    where T : class
+{
+    protected ScaffoldedNotification(T original, T scaffold, int parentId, EventMessages messages)
+        : base(original, messages)
+    {
+        Scaffold = scaffold;
+        ParentId = parentId;
+    }
+
+    public T Original => Target;
+
+    public T Scaffold { get; }
+
+    public int ParentId { get; }
+}

src/Umbraco.Infrastructure/DependencyInjection/UmbracoBuilder.CoreServices.cs

@@ -358,10 +358,13 @@ public static partial class UmbracoBuilderExtensions
         builder
             .AddNotificationHandler<ContentSavingNotification, BlockListPropertyNotificationHandler>()
             .AddNotificationHandler<ContentCopyingNotification, BlockListPropertyNotificationHandler>()
+            .AddNotificationHandler<ContentScaffoldedNotification, BlockListPropertyNotificationHandler>()
             .AddNotificationHandler<ContentSavingNotification, BlockGridPropertyNotificationHandler>()
             .AddNotificationHandler<ContentCopyingNotification, BlockGridPropertyNotificationHandler>()
+            .AddNotificationHandler<ContentScaffoldedNotification, BlockGridPropertyNotificationHandler>()
             .AddNotificationHandler<ContentSavingNotification, NestedContentPropertyHandler>()
             .AddNotificationHandler<ContentCopyingNotification, NestedContentPropertyHandler>()
+            .AddNotificationHandler<ContentScaffoldedNotification, NestedContentPropertyHandler>()
             .AddNotificationHandler<ContentCopiedNotification, FileUploadPropertyEditor>()
             .AddNotificationHandler<ContentDeletedNotification, FileUploadPropertyEditor>()
             .AddNotificationHandler<MediaDeletedNotification, FileUploadPropertyEditor>()

src/Umbraco.Infrastructure/PropertyEditors/ComplexPropertyEditorContentNotificationHandler.cs

@@ -10,9 +10,16 @@ using Umbraco.Extensions;
 
 namespace Umbraco.Cms.Core.PropertyEditors;
 
+/// <summary>
+/// Handles nested Udi keys when
+/// - saving: Empty keys get generated
+/// - copy: keys get replaced by new ones while keeping references intact
+/// - scaffolding: keys get replaced by new ones while keeping references intact
+/// </summary>
 public abstract class ComplexPropertyEditorContentNotificationHandler :
     INotificationHandler<ContentSavingNotification>,
-    INotificationHandler<ContentCopyingNotification>
+    INotificationHandler<ContentCopyingNotification>,
+    INotificationHandler<ContentScaffoldedNotification>
 {
     protected abstract string EditorAlias { get; }
 
@@ -31,6 +38,12 @@ public abstract class ComplexPropertyEditorContentNotificationHandler :
         }
     }
 
+    public void Handle(ContentScaffoldedNotification notification)
+    {
+        IEnumerable<IProperty> props = notification.Scaffold.GetPropertiesByEditor(EditorAlias);
+        UpdatePropertyValues(props, false);
+    }
+
     protected abstract string FormatPropertyValue(string rawJson, bool onlyMissingKeys);
 
     private void UpdatePropertyValues(IEnumerable<IProperty> props, bool onlyMissingKeys)

src/Umbraco.Web.BackOffice/Controllers/ContentController.cs

@@ -16,6 +16,7 @@ using Umbraco.Cms.Core.Models.ContentEditing;
 using Umbraco.Cms.Core.Models.Editors;
 using Umbraco.Cms.Core.Models.Membership;
 using Umbraco.Cms.Core.Models.Validation;
+using Umbraco.Cms.Core.Notifications;
 using Umbraco.Cms.Core.Persistence.Querying;
 using Umbraco.Cms.Core.PropertyEditors;
 using Umbraco.Cms.Core.Routing;
@@ -623,17 +624,33 @@ public class ContentController : ContentControllerBase
     [OutgoingEditorModelEvent]
     public ActionResult<ContentItemDisplay?> GetEmptyBlueprint(int blueprintId, int parentId)
     {
-        IContent? blueprint = _contentService.GetBlueprintById(blueprintId);
-        if (blueprint == null)
+        IContent? scaffold;
+        using (ICoreScope scope = _scopeProvider.CreateCoreScope())
         {
-            return NotFound();
+            IContent? blueprint = _contentService.GetBlueprintById(blueprintId);
+            if (blueprint is null)
+            {
+                return NotFound();
+            }
+            scaffold = (IContent)blueprint.DeepClone();
+
+            scaffold.Id = 0;
+            scaffold.Name = string.Empty;
+            scaffold.ParentId = parentId;
+
+            var scaffoldedNotification = new ContentScaffoldedNotification(blueprint, scaffold, parentId, new EventMessages());
+            if (scope.Notifications.PublishCancelable(scaffoldedNotification))
+            {
+                scope.Complete();
+                return Problem("Scaffolding was cancelled");
+            }
+
+            scope.Complete();
         }
 
-        blueprint.Id = 0;
-        blueprint.Name = string.Empty;
-        blueprint.ParentId = parentId;
 
-        ContentItemDisplay? mapped = _umbracoMapper.Map<ContentItemDisplay>(blueprint);
+
+        ContentItemDisplay? mapped = _umbracoMapper.Map<ContentItemDisplay>(scaffold);
 
         if (mapped is not null)
         {