Fix execution order of workflow content handler to prevent incomplete data (#18173)

Author: gvkries

src/OrchardCore.Modules/OrchardCore.Contents/Workflows/Startup.cs

@@ -28,7 +28,22 @@ public override void ConfigureServices(IServiceCollection services)
         services.AddActivity<RetrieveContentTask, RetrieveContentTaskDisplayDriver>();
         services.AddActivity<UpdateContentTask, UpdateContentTaskDisplayDriver>();
 
-        services.AddScoped<IContentHandler, ContentsHandler>();
         services.AddScoped<IWorkflowValueSerializer, ContentItemSerializer>();
     }
 }
+
+[RequireFeatures("OrchardCore.Workflows")]
+public sealed class ContentHandlerStartup : StartupBase
+{
+    // The order is set to OrchardCoreConstants.ConfigureOrder.WorkflowsContentHandlers to ensure the workflows content
+    // handler is registered first in the DI container. This causes the workflows content handler to be invoked last
+    // when content events are triggered, allowing it to access the final state of the content item after all other
+    // content handlers have executed. Note: handlers are resolved in reverse order, so setting this constant ensures
+    // this handler runs last during content item created, updated, etc. events.
+    public override int Order => OrchardCoreConstants.ConfigureOrder.WorkflowsContentHandlers;
+
+    public override void ConfigureServices(IServiceCollection services)
+    {
+        services.AddScoped<IContentHandler, ContentsHandler>();
+    }
+}

src/OrchardCore/OrchardCore.Abstractions/OrchardCoreConstants.cs

@@ -76,6 +76,10 @@ public static class ConfigureOrder
 
         // The UrlRewriting module should be registered before any other module that deals with URLs.
         public const int UrlRewriting = InfrastructureService + 100;
+
+        // The Workflows content handler should be registered before other content handlers to ensure it
+        // processes content events last.
+        public const int WorkflowsContentHandlers = InfrastructureService + 100;
     }
 
     public static class DisplayType