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Adds Disposal Logic for IJSStreamReference in PullFromJSDataStream #64426

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Adds Disposal Logic for IJSStreamReference in PullFromJSDataStream #64426

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b1817f2
Refactor PullFromJSDataStream disposal logic and add unit test for Di…
Nov 18, 2025
64a0116
Nov 18, 2025
750c9b3
Nov 18, 2025
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51 changes: 48 additions & 3 deletions src/Components/Shared/src/PullFromJSDataStream.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -14,8 +14,9 @@ internal sealed class PullFromJSDataStream : Stream
private readonly IJSRuntime _runtime;
private readonly IJSStreamReference _jsStreamReference;
private readonly long _totalLength;
private readonly CancellationToken _streamCancellationToken;
private readonly CancellationTokenSource _streamCts;
private long _offset;
private bool _isDisposed;

public static PullFromJSDataStream CreateJSDataStream(
IJSRuntime runtime,
Expand All @@ -36,8 +37,9 @@ private PullFromJSDataStream(
_runtime = runtime;
_jsStreamReference = jsStreamReference;
_totalLength = totalLength;
_streamCancellationToken = cancellationToken;
_streamCts = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
_offset = 0;

}

public override bool CanRead => true;
Expand Down Expand Up @@ -88,7 +90,7 @@ public override async ValueTask<int> ReadAsync(Memory<byte> buffer, Cancellation
private void ThrowIfCancellationRequested(CancellationToken cancellationToken)
{
if (cancellationToken.IsCancellationRequested ||
_streamCancellationToken.IsCancellationRequested)
_streamCts.IsCancellationRequested)
{
throw new TaskCanceledException();
}
Expand All @@ -110,4 +112,47 @@ private async ValueTask<byte[]> RequestDataFromJSAsync(int numBytesToRead)
}
return bytesRead;
}

protected override void Dispose(bool disposing)
{
if (_isDisposed)
{
return;
}
_streamCts?.Cancel();
try
{
_ = _jsStreamReference?.DisposeAsync().Preserve();
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Copilot AI Nov 18, 2025

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The Preserve() extension method does not exist in the codebase. This will cause a compilation error.

To properly handle the fire-and-forget disposal in a synchronous context, you should use .AsTask() or simply discard the ValueTask without calling any method on it. Consider one of these alternatives:

// Option 1: Just discard the ValueTask (allows it to be collected)
_ = _jsStreamReference?.DisposeAsync();

or if you need to ensure the task runs:

// Option 2: Convert to Task (ensures the task runs)
_ = _jsStreamReference?.DisposeAsync().AsTask();
Suggested change
_ = _jsStreamReference?.DisposeAsync().Preserve();
_ = _jsStreamReference?.DisposeAsync();

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}
catch
{
}

_isDisposed = true;

base.Dispose(disposing);
}
public override async ValueTask DisposeAsync()
{
if (_isDisposed)
{
return;
}

_streamCts?.Cancel();
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The _streamCts CancellationTokenSource is never disposed, which can lead to resource leaks. You should dispose it in both Dispose and DisposeAsync methods.

Add disposal after cancellation:

_streamCts?.Cancel();
_streamCts?.Dispose();

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try
{
if (_jsStreamReference is not null)
{
await _jsStreamReference.DisposeAsync();
}
}
catch
{
}

_isDisposed = true;

await base.DisposeAsync();
}
}
23 changes: 22 additions & 1 deletion src/Components/WebAssembly/WebAssembly/test/PullFromJSDataStreamTest.cs
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Original file line number Diff line number Diff line change
@@ -1,7 +1,6 @@
// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System.Diagnostics.CodeAnalysis;
using Microsoft.AspNetCore.InternalTesting;
using Microsoft.JSInterop;
using Moq;
Expand Down Expand Up @@ -101,6 +100,28 @@ public async Task ReceiveData_JSProvidesExcessData_Throws2()
Assert.Equal("Failed to read the requested number of bytes from the stream.", ex.Message);
}

[Fact]
public void Dispose_CallsDisposeAsyncOnJSStreamReference()
{
var jsStreamReferenceMock = new Mock<IJSStreamReference>();
var stream = PullFromJSDataStream.CreateJSDataStream(_jsRuntime, jsStreamReferenceMock.Object, totalLength: 10, cancellationToken: CancellationToken.None);

stream.Dispose();

jsStreamReferenceMock.Verify(x => x.DisposeAsync(), Times.Once);
}

[Fact]
public async Task DisposeAsync_CallsDisposeAsyncOnJSStreamReference()
{
var jsStreamReferenceMock = new Mock<IJSStreamReference>();
var stream = PullFromJSDataStream.CreateJSDataStream(_jsRuntime, jsStreamReferenceMock.Object, totalLength: 10, cancellationToken: CancellationToken.None);

await stream.DisposeAsync();

jsStreamReferenceMock.Verify(x => x.DisposeAsync(), Times.Once);
}

private static PullFromJSDataStream CreateJSDataStream(byte[] data, IJSRuntime runtime = null)
{
runtime ??= new TestJSRuntime(data);
Expand Down
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