Remove last ! from Caching.Abstractions

src/libraries/Microsoft.Extensions.Caching.Abstractions/src/CacheEntryExtensions.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System;
+using System.Diagnostics.CodeAnalysis;
 using Microsoft.Extensions.Primitives;
 
 namespace Microsoft.Extensions.Caching.Memory
@@ -93,7 +94,7 @@ public static ICacheEntry RegisterPostEvictionCallback(
  {
  ThrowHelper.ThrowIfNull(callback);
 
- return entry.RegisterPostEvictionCallback(callback, state: null);
+ return entry.RegisterPostEvictionCallbackNoValidation(callback, state: null);
  }
 
  /// <summary>
@@ -110,6 +111,14 @@ public static ICacheEntry RegisterPostEvictionCallback(
  {
  ThrowHelper.ThrowIfNull(callback);
 
+ return entry.RegisterPostEvictionCallbackNoValidation(callback, state);
+ }
+
+ private static ICacheEntry RegisterPostEvictionCallbackNoValidation(
+ this ICacheEntry entry,
+ PostEvictionDelegate callback,
+ object? state)
+ {
  entry.PostEvictionCallbacks.Add(new PostEvictionCallbackRegistration()
  {
  EvictionCallback = callback,
@@ -172,12 +181,24 @@ public static ICacheEntry SetOptions(this ICacheEntry entry, MemoryCacheEntryOpt
  entry.AddExpirationToken(expirationToken);
  }
 
- foreach (PostEvictionCallbackRegistration postEvictionCallback in options.PostEvictionCallbacks)
+ for (int i = 0; i < options.PostEvictionCallbacks.Count; i++)
  {
- entry.RegisterPostEvictionCallback(postEvictionCallback.EvictionCallback!, postEvictionCallback.State);
+ PostEvictionCallbackRegistration postEvictionCallback = options.PostEvictionCallbacks[i];
+ if (postEvictionCallback.EvictionCallback is null)
+ ThrowNullCallback(i, nameof(options));
+
+ entry.RegisterPostEvictionCallbackNoValidation(postEvictionCallback.EvictionCallback, postEvictionCallback.State);
  }
 
  return entry;
  }
+
+ [DoesNotReturn]
+ private static void ThrowNullCallback(int index, string paramName)
+ {
+ string message =
+ $"MemoryCacheEntryOptions.PostEvictionCallbacks contains a PostEvictionCallbackRegistration with a null EvictionCallback at index {index}.";
+ throw new ArgumentException(message, paramName);
+ }
  }
 }

src/libraries/Microsoft.Extensions.Caching.Memory/tests/MemoryCacheSetAndRemoveTests.cs

@@ -406,6 +406,29 @@ public void ClearClears()
  }
  }
 
+ [Fact]
+ public void SetNullCallback_NotAllowed_ArgumentException()
+ {
+ var cache = CreateCache();
+ const string someKey = "test";
+ var entry = cache.CreateEntry(someKey);
+
+ var options = new MemoryCacheEntryOptions();
+
+ var notNullCallback = new PostEvictionCallbackRegistration()
+ {
+ EvictionCallback = (_, _, _, _) => {}
+ };
+
+ options.PostEvictionCallbacks.Add(notNullCallback);
+
+ var nullCallback = new PostEvictionCallbackRegistration();
+
+ options.PostEvictionCallbacks.Add(nullCallback);
+
+ Assert.Throws<ArgumentException>(() => entry.SetOptions(options));
+ }
+
  [Fact]
  public void RemoveRemovesAndInvokesCallback()
  {