Fix PostEvictionCallbacks bug

src/libraries/Microsoft.Extensions.Caching.Memory/src/CacheEntry.CacheEntryTokens.cs

@@ -23,7 +23,7 @@ private sealed class CacheEntryTokens
  internal List<IChangeToken> ExpirationTokens => _expirationTokens ??= new List<IChangeToken>();
  internal List<PostEvictionCallbackRegistration> PostEvictionCallbacks => _postEvictionCallbacks ??= new List<PostEvictionCallbackRegistration>();
 
- internal void AttachTokens()
+ internal void AttachTokens(CacheEntry cacheEntry)
  {
  if (_expirationTokens != null)
  {
@@ -35,7 +35,7 @@ internal void AttachTokens()
  if (expirationToken.ActiveChangeCallbacks)
  {
  _expirationTokenRegistrations ??= new List<IDisposable>(1);
- IDisposable registration = expirationToken.RegisterChangeCallback(ExpirationCallback, this);
+ IDisposable registration = expirationToken.RegisterChangeCallback(ExpirationCallback, cacheEntry);
  _expirationTokenRegistrations.Add(registration);
  }
  }

src/libraries/Microsoft.Extensions.Caching.Memory/src/CacheEntry.cs

@@ -199,7 +199,7 @@ bool FullCheck(in DateTimeOffset offset)
  }
  }
 
- internal void AttachTokens() => _tokens?.AttachTokens();
+ internal void AttachTokens() => _tokens?.AttachTokens(this);
 
  private static void ExpirationTokensExpired(object obj)
  {

src/libraries/Microsoft.Extensions.Caching.Memory/tests/Microsoft.Extensions.Caching.Memory.Tests.csproj

@@ -5,6 +5,11 @@
  <EnableDefaultItems>true</EnableDefaultItems>
  </PropertyGroup>
 
+ <ItemGroup>
+ <Compile Include="$(CommonTestPath)System\Threading\Tasks\TaskTimeoutExtensions.cs"
+ Link="Common\System\Threading\Tasks\TaskTimeoutExtensions.cs" />
+ </ItemGroup>
+
  <ItemGroup>
  <ProjectReference Include="..\src\Microsoft.Extensions.Caching.Memory.csproj" SkipUseReferenceAssembly="true" />
  <ProjectReference Include="$(LibrariesProjectRoot)Microsoft.Extensions.DependencyInjection\src\Microsoft.Extensions.DependencyInjection.csproj" />

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

@@ -207,6 +207,33 @@ public void TokenExpiresOnRegister()
  Assert.Null(result);
  }
 
+ [Fact]
+ public async Task PostEvictionCallbacksGetInvokedWhenMemoryCacheEntriesExpireWithAnActiveChangeToken()
+ {
+ var cache = new MemoryCache(new MemoryCacheOptions());
+ var key = new object();
+
+ var cts = new CancellationTokenSource(TimeSpan.FromSeconds(1));
+ var tcs = new TaskCompletionSource<object>();
+
+ cache.Set(key, new object(), new MemoryCacheEntryOptions
+ {
+ ExpirationTokens = { new Microsoft.Extensions.Primitives.CancellationChangeToken(cts.Token) },
+ PostEvictionCallbacks = { new PostEvictionCallbackRegistration { EvictionCallback = OnEntryEvicted } },
+ });
+
+ Assert.True(cache.TryGetValue(key, out _));
+
+ await Task.Run(() => tcs.Task.TimeoutAfter(TimeSpan.FromSeconds(10)));
+
+ Assert.False(cache.TryGetValue(key, out _));
+
+ void OnEntryEvicted(object key, object value, EvictionReason reason, object state)
+ {
+ tcs.TrySetResult(new object());
+ }
+ }
+
  internal class TestToken : IChangeToken
  {
  private bool _hasChanged;