From b3801355002707feb7bae617ca8dd20d2720c151 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A1ra=20El-Saig?= <sara.el-saig@lombiq.com>
Date: Thu, 9 Nov 2023 16:35:12 +0100
Subject: [PATCH 1/3] Fix bug in SetItems extension method.

---
 .../Extensions/CollectionExtensions.cs                        | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Lombiq.HelpfulLibraries.Common/Extensions/CollectionExtensions.cs b/Lombiq.HelpfulLibraries.Common/Extensions/CollectionExtensions.cs
index 0217ae31..03c8e336 100644
--- a/Lombiq.HelpfulLibraries.Common/Extensions/CollectionExtensions.cs
+++ b/Lombiq.HelpfulLibraries.Common/Extensions/CollectionExtensions.cs
@@ -42,6 +42,10 @@ public static void RemoveAll<T>(this ICollection<T> collection, Func<T, bool> pr
     /// </summary>
     public static void SetItems<T>(this ICollection<T> collection, IEnumerable<T> newValues)
     {
+        // If the two variables point to the same object, nothing should be done. Otherwise this would clear the
+        // collection and then add nothing to it.
+        if (Equals(collection, newValues)) return;
+
         collection.Clear();
         collection.AddRange(newValues);
     }

From d651eb45716f6d1de8131bc57b734bc716c679d1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A1ra=20El-Saig?= <sara.el-saig@lombiq.com>
Date: Thu, 9 Nov 2023 16:35:39 +0100
Subject: [PATCH 2/3] Copy UpdateModelExtensions from OCC.

---
 .../Mvc/UpdateModelExtensions.cs               | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)
 create mode 100644 Lombiq.HelpfulLibraries.OrchardCore/Mvc/UpdateModelExtensions.cs

diff --git a/Lombiq.HelpfulLibraries.OrchardCore/Mvc/UpdateModelExtensions.cs b/Lombiq.HelpfulLibraries.OrchardCore/Mvc/UpdateModelExtensions.cs
new file mode 100644
index 00000000..7a9cfe6a
--- /dev/null
+++ b/Lombiq.HelpfulLibraries.OrchardCore/Mvc/UpdateModelExtensions.cs
@@ -0,0 +1,18 @@
+using Microsoft.AspNetCore.Mvc.ModelBinding;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace OrchardCore.DisplayManagement.ModelBinding;
+
+public static class UpdateModelExtensions
+{
+    public static IEnumerable<ModelError> GetModelErrors(this IUpdateModel updateModel) =>
+        updateModel
+            .ModelState
+            .Values
+            .SelectMany(entry => entry.Errors)
+            .Where(error => !string.IsNullOrWhiteSpace(error.ErrorMessage));
+
+    public static IEnumerable<string> GetModelErrorMessages(this IUpdateModel updateModel) =>
+        updateModel.GetModelErrors().Select(error => error.ErrorMessage);
+}

From f9571f85f25befebaba4226e08ed9cee35005e62 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A1ra=20El-Saig?= <sara.el-saig@lombiq.com>
Date: Thu, 9 Nov 2023 16:48:25 +0100
Subject: [PATCH 3/3] Add docs.

---
 Lombiq.HelpfulLibraries.OrchardCore/Docs/Mvc.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Lombiq.HelpfulLibraries.OrchardCore/Docs/Mvc.md b/Lombiq.HelpfulLibraries.OrchardCore/Docs/Mvc.md
index 9faa4ac3..8070ee90 100644
--- a/Lombiq.HelpfulLibraries.OrchardCore/Docs/Mvc.md
+++ b/Lombiq.HelpfulLibraries.OrchardCore/Docs/Mvc.md
@@ -5,6 +5,7 @@
 - `OrchardControllerExtensions`: Adds extension methods like `RedirectToContentDisplay(content)` to `Controller` objects.
 - `ResultExecutingContextExtensions`: contains shortcuts for common context operations in `IAsyncResultFilter`s.
 - `ShapeResultExtensions`: Adds extensions methods generating placement strings on your shape description, such as `UseTab()`.
+- `UpdateModelExtensions`: Adds extension methods for working with the `IUpdateModel` such as `GetModelErrors()`.
 - `UrlHelperExtensions`: Adds extension methods to the `@Url` helper, such as `EditContentItemWithTab()`.
 
 ## `TypedRoute`