From 273f017adc0c655cde38f7ffbacba027b4831f68 Mon Sep 17 00:00:00 2001
From: Stuart Turner <stuart@turner-isageek.com>
Date: Mon, 20 Jul 2026 10:51:10 -0500
Subject: [PATCH 1/2] Add support for nullable request/response

---
 .../ApplicationCache.cs                       |  4 ++--
 .../NullableTypesCache.cs                     | 23 +++++++++++++++++++
 2 files changed, 25 insertions(+), 2 deletions(-)
 create mode 100644 tests/Immediate.Cache.FunctionalTests/NullableTypesCache.cs

diff --git a/src/Immediate.Cache.Shared/ApplicationCache.cs b/src/Immediate.Cache.Shared/ApplicationCache.cs
index 18ba9e8..ce13529 100644
--- a/src/Immediate.Cache.Shared/ApplicationCache.cs
+++ b/src/Immediate.Cache.Shared/ApplicationCache.cs
@@ -23,8 +23,8 @@ public abstract class ApplicationCache<TRequest, TResponse>(
 	IMemoryCache memoryCache,
 	Owned<IHandler<TRequest, TResponse>> handler
 )
-	where TRequest : class
-	where TResponse : class
+	where TRequest : class?
+	where TResponse : class?
 {
 	private readonly Lock _lock = new();
 
diff --git a/tests/Immediate.Cache.FunctionalTests/NullableTypesCache.cs b/tests/Immediate.Cache.FunctionalTests/NullableTypesCache.cs
new file mode 100644
index 0000000..0473d6b
--- /dev/null
+++ b/tests/Immediate.Cache.FunctionalTests/NullableTypesCache.cs
@@ -0,0 +1,23 @@
+using Immediate.Cache.Shared;
+using Immediate.Handlers.Shared;
+
+namespace Immediate.Cache.FunctionalTests;
+
+[CacheFor<NullableTypesHandler>]
+public sealed partial class NullableTypesCache
+{
+	protected override string TransformKey(NullableTypesHandler.Query? request) =>
+		$"NullableTypesHandler(query: {request})";
+}
+
+[Handler]
+public sealed partial class NullableTypesHandler
+{
+	public sealed record Query;
+	public sealed record Response;
+
+	private async ValueTask<Response?> HandleAsync(Query? _, CancellationToken __)
+	{
+		return null;
+	}
+}

From 86e7e69f44113deb1174ff4a17a05e76c231ebda Mon Sep 17 00:00:00 2001
From: Stuart Turner <stuart@turner-isageek.com>
Date: Mon, 20 Jul 2026 11:03:26 -0500
Subject: [PATCH 2/2] Update expectations to match constraints

---
 src/Immediate.Cache.Shared/ApplicationCache.cs | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/Immediate.Cache.Shared/ApplicationCache.cs b/src/Immediate.Cache.Shared/ApplicationCache.cs
index ce13529..319e218 100644
--- a/src/Immediate.Cache.Shared/ApplicationCache.cs
+++ b/src/Immediate.Cache.Shared/ApplicationCache.cs
@@ -57,8 +57,6 @@ protected virtual MemoryCacheEntryOptions GetCacheEntryOptions() =>
 
 	private CacheValue GetCacheValue(TRequest request)
 	{
-		ArgumentNullException.ThrowIfNull(request);
-
 		var key = TransformKey(request);
 
 		if (!memoryCache.TryGetValue(key, out var result))
@@ -76,7 +74,10 @@ private CacheValue GetCacheValue(TRequest request)
 			}
 		}
 
-		return (CacheValue)result!;
+		if (result is not CacheValue cacheValue)
+			throw new InvalidOperationException($"An unknown type has been stored as the cache value for key `{key}`; Immediate.Cache is unable to operate.");
+
+		return cacheValue;
 	}
 
 	/// <summary>