From f90fb582c70cbfbb8e844914809f1e982d4e72ef Mon Sep 17 00:00:00 2001
From: William Forney <william@williamforney.com>
Date: Wed, 19 Aug 2026 09:08:44 -0700
Subject: [PATCH 1/2] fix(core): [B] cache XML serializers

Avoid repeated XmlSerializer construction in XDocument deserialization.

Assisted-by: OpenAI:GPT-5.6 Luna
---
 SharedCode.Core/Xml/XDocumentExtensions.cs | 36 +++++++++++++++++++++-
 1 file changed, 35 insertions(+), 1 deletion(-)

diff --git a/SharedCode.Core/Xml/XDocumentExtensions.cs b/SharedCode.Core/Xml/XDocumentExtensions.cs
index 27700ad..6dffbe3 100644
--- a/SharedCode.Core/Xml/XDocumentExtensions.cs
+++ b/SharedCode.Core/Xml/XDocumentExtensions.cs
@@ -8,6 +8,11 @@ namespace SharedCode.Xml;
 /// </summary>
 public static class XDocumentExtensions
 {
+	/// <summary>
+	/// Cached XML serializers by runtime type.
+	/// </summary>
+	private static readonly Dictionary<RuntimeTypeHandle, XmlSerializer> XmlSerializers = [];
+
 	/// <summary>
 	/// Deserializes the specified XML document.
 	/// </summary>
@@ -19,8 +24,37 @@ public static class XDocumentExtensions
 	{
 		_ = xmlDocument ?? throw new ArgumentNullException(nameof(xmlDocument));
 
-		var xmlSerializer = new XmlSerializer(typeof(T));
+		var xmlSerializer = GetXmlSerializer(typeof(T));
 		using var reader = xmlDocument.CreateReader();
 		return (T?)xmlSerializer.Deserialize(reader);
 	}
+
+	/// <summary>
+	/// Gets the XML serializer for the specified <paramref name="type" />.
+	/// </summary>
+	/// <param name="type">The type handled by the serializer.</param>
+	/// <returns>The <see cref="XmlSerializer" /> for the <paramref name="type" />.</returns>
+	/// <exception cref="ArgumentNullException">type</exception>
+	private static XmlSerializer GetXmlSerializer(Type type)
+	{
+		_ = type ?? throw new ArgumentNullException(nameof(type));
+
+		if (XmlSerializers.TryGetValue(type.TypeHandle, out var serializer))
+		{
+			return serializer;
+		}
+
+		lock (XmlSerializers)
+		{
+			if (XmlSerializers.TryGetValue(type.TypeHandle, out serializer))
+			{
+				return serializer;
+			}
+
+			serializer = new XmlSerializer(type);
+			XmlSerializers.Add(type.TypeHandle, serializer);
+		}
+
+		return serializer;
+	}
 }

From 9b74898b3fb793450ba7c65be8e549f6b3d705e4 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 20 Aug 2026 03:02:03 +0000
Subject: [PATCH 2/2] fix(core): address XML serializer review feedback

Co-authored-by: wforney <79032+wforney@users.noreply.github.com>
---
 SharedCode.Core/Xml/XDocumentExtensions.cs | 59 ++++++++++------------
 1 file changed, 27 insertions(+), 32 deletions(-)

diff --git a/SharedCode.Core/Xml/XDocumentExtensions.cs b/SharedCode.Core/Xml/XDocumentExtensions.cs
index 6dffbe3..b63b235 100644
--- a/SharedCode.Core/Xml/XDocumentExtensions.cs
+++ b/SharedCode.Core/Xml/XDocumentExtensions.cs
@@ -8,10 +8,10 @@ namespace SharedCode.Xml;
 /// </summary>
 public static class XDocumentExtensions
 {
-	/// <summary>
-	/// Cached XML serializers by runtime type.
-	/// </summary>
-	private static readonly Dictionary<RuntimeTypeHandle, XmlSerializer> XmlSerializers = [];
+    /// <summary>
+    /// Cached XML serializers by runtime type.
+    /// </summary>
+    private static readonly Dictionary<RuntimeTypeHandle, XmlSerializer> XmlSerializers = [];
 
 	/// <summary>
 	/// Deserializes the specified XML document.
@@ -29,32 +29,27 @@ public static class XDocumentExtensions
 		return (T?)xmlSerializer.Deserialize(reader);
 	}
 
-	/// <summary>
-	/// Gets the XML serializer for the specified <paramref name="type" />.
-	/// </summary>
-	/// <param name="type">The type handled by the serializer.</param>
-	/// <returns>The <see cref="XmlSerializer" /> for the <paramref name="type" />.</returns>
-	/// <exception cref="ArgumentNullException">type</exception>
-	private static XmlSerializer GetXmlSerializer(Type type)
-	{
-		_ = type ?? throw new ArgumentNullException(nameof(type));
-
-		if (XmlSerializers.TryGetValue(type.TypeHandle, out var serializer))
-		{
-			return serializer;
-		}
-
-		lock (XmlSerializers)
-		{
-			if (XmlSerializers.TryGetValue(type.TypeHandle, out serializer))
-			{
-				return serializer;
-			}
-
-			serializer = new XmlSerializer(type);
-			XmlSerializers.Add(type.TypeHandle, serializer);
-		}
-
-		return serializer;
-	}
+    /// <summary>
+    /// Gets the XML serializer for the specified <paramref name="type" />.
+    /// </summary>
+    /// <param name="type">The type handled by the serializer.</param>
+    /// <returns>The <see cref="XmlSerializer" /> for the <paramref name="type" />.</returns>
+    /// <exception cref="ArgumentNullException">type</exception>
+    private static XmlSerializer GetXmlSerializer(Type type)
+    {
+        _ = type ?? throw new ArgumentNullException(nameof(type));
+
+        lock (XmlSerializers)
+        {
+            if (XmlSerializers.TryGetValue(type.TypeHandle, out var serializer))
+            {
+                return serializer;
+            }
+
+            serializer = new XmlSerializer(type);
+            XmlSerializers.Add(type.TypeHandle, serializer);
+
+            return serializer;
+        }
+    }
 }