Add missing clearing of pooled arrays

src/Components/Components/src/Microsoft.AspNetCore.Components.csproj

@@ -26,6 +26,7 @@
     <Compile Include="$(SharedSourceRoot)UrlDecoder\UrlDecoder.cs" LinkBase="Shared" />
     <Compile Include="$(SharedSourceRoot)Metrics\MetricsConstants.cs" LinkBase="Shared" />
     <Compile Include="$(SharedSourceRoot)Components\ComponentsActivityLinkStore.cs" LinkBase="Shared" />
+    <Compile Include="$(SharedSourceRoot)Buffers\ArrayPoolExtensions.cs" LinkBase="Shared" />
   </ItemGroup>
 
   <Import Project="Microsoft.AspNetCore.Components.Routing.targets" />

src/Components/Components/src/NavigationManager.cs

@@ -447,7 +447,7 @@ protected async ValueTask<bool> NotifyLocationChangingAsync(string uri, string?
                 }
                 finally
                 {
-                    ArrayPool<Func<LocationChangingContext, ValueTask>>.Shared.Return(locationChangingHandlersCopy);
+                    ArrayPool<Func<LocationChangingContext, ValueTask>>.Shared.Return(locationChangingHandlersCopy, handlerCount);
                 }
             }
 

src/Components/Endpoints/src/FormMapping/Converters/CollectionAdapters/ArrayPoolBufferAdapter.cs

@@ -17,7 +17,7 @@ public static PooledBuffer Add(ref PooledBuffer buffer, TElement element)
         {
             var newBuffer = ArrayPool<TElement>.Shared.Rent(buffer.Data.Length * 2);
             Array.Copy(buffer.Data, newBuffer, buffer.Data.Length);
-            ArrayPool<TElement>.Shared.Return(buffer.Data);
+            ArrayPool<TElement>.Shared.ReturnAndClearReferences(buffer.Data, buffer.Count);
             buffer.Data = newBuffer;
         }
 
@@ -28,7 +28,7 @@ public static PooledBuffer Add(ref PooledBuffer buffer, TElement element)
     public static TCollection ToResult(PooledBuffer buffer)
     {
         var result = TCollectionFactory.ToResultCore(buffer.Data, buffer.Count);
-        ArrayPool<TElement>.Shared.Return(buffer.Data);
+        ArrayPool<TElement>.Shared.ReturnAndClearReferences(buffer.Data, buffer.Count);
         return result;
     }
 

src/Components/Endpoints/src/FormMapping/PrefixResolver.cs

@@ -38,7 +38,7 @@ public void Dispose()
     {
         if (_sortedKeys != null)
         {
-            ArrayPool<FormKey>.Shared.Return(_sortedKeys);
+            ArrayPool<FormKey>.Shared.Return(_sortedKeys, _length);
         }
     }
 

src/Components/Endpoints/src/Microsoft.AspNetCore.Components.Endpoints.csproj

@@ -35,9 +35,8 @@
     <Compile Include="$(SharedSourceRoot)LinkerFlags.cs" LinkBase="Shared" />
     <Compile Include="$(SharedSourceRoot)Components\ComponentsActivityLinkStore.cs" LinkBase="Shared" />
     <Compile Include="$(ComponentsSharedSourceRoot)src\HotReloadManager.cs" LinkBase="HotReload" />
-
     <Compile Include="$(SharedSourceRoot)PropertyHelper\**\*.cs" />
-
+    <Compile Include="$(SharedSourceRoot)Buffers\ArrayPoolExtensions.cs" LinkBase="Shared" />
   </ItemGroup>
 
   <ItemGroup>

src/Http/Http.Abstractions/src/Microsoft.AspNetCore.Http.Abstractions.csproj

@@ -32,6 +32,7 @@ Microsoft.AspNetCore.Http.HttpResponse</Description>
     <Compile Include="$(SharedSourceRoot)Debugger\DictionaryItemDebugView.cs" LinkBase="Shared" />
     <Compile Include="$(SharedSourceRoot)Debugger\DictionaryDebugView.cs" LinkBase="Shared" />
     <Compile Include="$(SharedSourceRoot)ValueStringBuilder\ValueListBuilder.cs" LinkBase="Shared" />
+    <Compile Include="$(SharedSourceRoot)Buffers\ArrayPoolExtensions.cs" LinkBase="Shared" />
   </ItemGroup>
 
   <ItemGroup>

src/Middleware/OutputCaching/src/Microsoft.AspNetCore.OutputCaching.csproj

@@ -23,6 +23,7 @@
 
   <ItemGroup>
     <Compile Include="$(RepoRoot)src\Shared\TaskToApm.cs" Link="Streams\TaskToApm.cs" />
+    <Compile Include="$(SharedSourceRoot)Buffers\ArrayPoolExtensions.cs" LinkBase="Shared" />
   </ItemGroup>
 
 </Project>

src/Middleware/OutputCaching/src/OutputCacheEntryFormatter.cs

@@ -46,10 +46,11 @@ public static async ValueTask StoreAsync(string key, OutputCacheEntry value, Has
         {
             if (store is IOutputCacheBufferStore bufferStore)
             {
-                await bufferStore.SetAsync(key, new(buffer.GetCommittedMemory()), CopyToLeasedMemory(tags, out var lease), duration, cancellationToken);
+                ReadOnlyMemory<string> leasedTags = CopyToLeasedMemory(tags, out var lease);
+                await bufferStore.SetAsync(key, new(buffer.GetCommittedMemory()), leasedTags, duration, cancellationToken);
                 if (lease is not null)
                 {
-                    ArrayPool<string>.Shared.Return(lease);
+                    ArrayPool<string>.Shared.Return(lease, leasedTags.Length);
                 }
             }
             else

src/Middleware/OutputCaching/src/RecyclableArrayBufferWriter.cs

@@ -32,11 +32,12 @@ public RecyclableArrayBufferWriter()
     public void Dispose()
     {
         var tmp = _buffer;
+        var count = _index;
         _index = 0;
         _buffer = Array.Empty<T>();
         if (tmp.Length != 0)
         {
-            ArrayPool<T>.Shared.Return(tmp);
+            ArrayPool<T>.Shared.ReturnAndClearReferences(tmp, count);
         }
     }
 
@@ -120,7 +121,7 @@ private void CheckAndResizeBuffer(int sizeHint)
             oldArray.AsSpan(0, _index).CopyTo(_buffer);
             if (oldArray.Length != 0)
             {
-                ArrayPool<T>.Shared.Return(oldArray);
+                ArrayPool<T>.Shared.ReturnAndClearReferences(oldArray, _index);
             }
         }
 

src/Middleware/WebSockets/src/Microsoft.AspNetCore.WebSockets.csproj

@@ -19,6 +19,7 @@
 
   <ItemGroup>
     <Compile Include="$(SharedSourceRoot)ValueStringBuilder\**\*.cs" />
+    <Compile Include="$(SharedSourceRoot)Buffers\ArrayPoolExtensions.cs" LinkBase="Shared" />
   </ItemGroup>
 
   <ItemGroup>

src/Mvc/Mvc.NewtonsoftJson/src/JsonArrayPool.cs

@@ -26,6 +26,6 @@ public void Return(T[]? array)
     {
         ArgumentNullException.ThrowIfNull(array);
 
-        _inner.Return(array);
+        _inner.ReturnAndClearReferences(array, array.Length);
     }
 }

src/Mvc/Mvc.NewtonsoftJson/src/Microsoft.AspNetCore.Mvc.NewtonsoftJson.csproj

@@ -26,6 +26,7 @@
     <Compile Include="..\..\Mvc.Core\src\Infrastructure\AsyncEnumerableReader.cs" />
     <Compile Include="$(SharedSourceRoot)ThrowHelpers\ArgumentNullThrowHelper.cs" LinkBase="Shared" />
     <Compile Include="$(SharedSourceRoot)CallerArgument\CallerArgumentExpressionAttribute.cs" LinkBase="Shared" />
+    <Compile Include="$(SharedSourceRoot)Buffers\ArrayPoolExtensions.cs" LinkBase="Shared" />
   </ItemGroup>
 
   <ItemGroup>

src/Shared/Buffers/ArrayPoolExtensions.cs

@@ -0,0 +1,40 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Runtime.CompilerServices;
+
+namespace System.Buffers;
+
+internal static class ArrayPoolExtensions
+{
+    /// <summary>
+    /// Clears the specified range and returns the array to the pool.
+    /// </summary>
+    public static void Return<T>(this ArrayPool<T> pool, T[] array, int lengthToClear)
+    {
+        array.AsSpan(0, lengthToClear).Clear();
+        pool.Return(array);
+    }
+
+    /// <summary>
+    /// Clears the specified range if <typeparamref name="T"/> is a reference type or
+    /// contains references and returns the array to the pool.
+    /// </summary>
+    /// <remarks>
+    /// For .NET Framework, falls back to checking if <typeparamref name="T"/> is not a primitive type
+    /// where <c>RuntimeHelpers.IsReferenceOrContainsReferences&lt;T&gt;()</c> is not available.
+    /// </remarks>
+    public static void ReturnAndClearReferences<T>(this ArrayPool<T> pool, T[] array, int lengthToClear)
+    {
+#if NET
+        if (RuntimeHelpers.IsReferenceOrContainsReferences<T>())
+#else
+        if (!typeof(T).IsPrimitive)
+#endif
+        {
+            array.AsSpan(0, lengthToClear).Clear();
+        }
+
+        pool.Return(array);
+    }
+}

src/Shared/ValueStringBuilder/ValueListBuilder.cs

@@ -60,7 +60,7 @@ public void Dispose()
         if (toReturn != null)
         {
             _arrayFromPool = null;
-            ArrayPool<T>.Shared.Return(toReturn);
+            ArrayPool<T>.Shared.ReturnAndClearReferences(toReturn, _pos);
         }
     }
 
@@ -95,7 +95,7 @@ private void Grow(int additionalCapacityRequired = 1)
         _span = _arrayFromPool = array;
         if (toReturn != null)
         {
-            ArrayPool<T>.Shared.Return(toReturn);
+            ArrayPool<T>.Shared.ReturnAndClearReferences(toReturn, _pos);
         }
     }
 }