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fix: Fix deadlock issues in async processors #307

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Merged
thomhurst merged 1 commit into from
Aug 9, 2025
Merged

fix: Fix deadlock issues in async processors #307

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11 changes: 10 additions & 1 deletion .claude/settings.local.json
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Original file line number Diff line number Diff line change
Expand Up @@ -12,7 +12,16 @@
"Bash(timeout 30 dotnet run:*)",
"Bash(.EnumerableAsyncProcessor.Example.exe)",
"Bash(EnumerableAsyncProcessor.Example.exe)",
"Bash(del \"EnumerableAsyncProcessor.UnitTests\\ValidationTests.cs\")"
"Bash(del \"EnumerableAsyncProcessor.UnitTests\\ValidationTests.cs\")",
"Bash(mkdir:*)",
"Bash(git add:*)",
"Bash(dotnet build)",
"Bash(dotnet build:*)",
"Bash(dotnet test)",
"Bash(dotnet test:*)",
"Bash(rg:*)",
"Bash(find:*)",
"Bash(timeout 30 dotnet test --no-build --verbosity minimal)"
],
"deny": []
}
Expand Down
12 changes: 8 additions & 4 deletions EnumerableAsyncProcessor/RunnableProcessors/Abstract/AbstractAsyncProcessorBase.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -148,12 +148,16 @@ protected virtual ValueTask DisposeAsyncCore()

public void Dispose()
{
// Use async disposal with ConfigureAwait(false) to avoid deadlocks
// and add a timeout to prevent indefinite blocking
// Use Task.Run to avoid deadlocks by running async disposal on thread pool
// Add timeout to prevent indefinite blocking
try
{
var disposeTask = DisposeAsync().ConfigureAwait(false);
disposeTask.GetAwaiter().GetResult();
var disposeTask = Task.Run(async () => await DisposeAsync().ConfigureAwait(false));
if (!disposeTask.Wait(TimeSpan.FromSeconds(30)))
{
// Log warning if disposal times out, but don't throw
// as per IDisposable pattern
}
}
catch
{
Expand Down
11 changes: 9 additions & 2 deletions ...ableAsyncProcessor/RunnableProcessors/AsyncEnumerable/AsyncEnumerableParallelProcessor.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -37,10 +37,17 @@ public async Task ExecuteAsync()
{
await channel.Writer.WriteAsync(item, cancellationToken).ConfigureAwait(false);
}
channel.Writer.Complete();
}
finally
catch (OperationCanceledException)
{
channel.Writer.Complete();
channel.Writer.TryComplete();
throw;
}
catch (Exception ex)
{
channel.Writer.TryComplete(ex);
throw;
}
}, cancellationToken);

Expand Down
93 changes: 77 additions & 16 deletions ...Processors/AsyncEnumerable/ResultProcessors/ResultAsyncEnumerableChannelBasedProcessor.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -62,9 +62,32 @@ private async IAsyncEnumerable<TOutput> ExecuteWithoutOrderPreservationAsync(Can
// Complete output when all processing is done
var completionTask = Task.Run(async () =>
{
await producerTask.ConfigureAwait(false);
await Task.WhenAll(consumerTasks).ConfigureAwait(false);
outputChannel.Writer.Complete();
Exception? exception = null;
try
{
await producerTask.ConfigureAwait(false);
await Task.WhenAll(consumerTasks).ConfigureAwait(false);
}
catch (Exception ex)
{
exception = ex;
}
finally
{
if (exception != null)
{
outputChannel.Writer.TryComplete(exception);
}
else
{
outputChannel.Writer.TryComplete();
}
}

if (exception != null)
{
throw exception;
}
}, cancellationToken);

// Yield results as they complete
Expand Down Expand Up @@ -138,7 +161,36 @@ private async IAsyncEnumerable<TOutput> ExecuteWithOrderPreservationAsync(Cancel
await Task.Delay(10, cancellationToken).ConfigureAwait(false);
}
}
outputChannel.Writer.Complete();
}, cancellationToken);

// Ensure channel completion when all tasks finish
var channelCompletionTask = Task.Run(async () =>
{
Exception? exception = null;
try
{
await yieldingTask.ConfigureAwait(false);
}
catch (Exception ex)
{
exception = ex;
}
finally
{
if (exception != null)
{
outputChannel.Writer.TryComplete(exception);
}
else
{
outputChannel.Writer.TryComplete();
}
}

if (exception != null)
{
throw exception;
}
}, cancellationToken);

// Yield from output channel
Expand All @@ -160,21 +212,30 @@ private async Task ProcessOrderedItemAsync(
SemaphoreSlim semaphore,
CancellationToken cancellationToken)
{
var tcs = new TaskCompletionSource<TOutput>();

await orderingLock.WaitAsync(cancellationToken).ConfigureAwait(false);
try
{
orderingDictionary[index] = tcs;
}
finally
{
orderingLock.Release();
}

try
{
var result = await _taskSelector(item).ConfigureAwait(false);

await orderingLock.WaitAsync(cancellationToken).ConfigureAwait(false);
try
{
var tcs = new TaskCompletionSource<TOutput>();
tcs.SetResult(result);
orderingDictionary[index] = tcs;
}
finally
{
orderingLock.Release();
}
tcs.TrySetResult(result);
}
catch (OperationCanceledException)
{
tcs.TrySetCanceled();
}
catch (Exception ex)
{
tcs.TrySetException(ex);
}
finally
{
Expand Down
12 changes: 8 additions & 4 deletions ...rocessor/RunnableProcessors/ResultProcessors/Abstract/ResultAbstractAsyncProcessorBase.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -155,12 +155,16 @@ protected virtual ValueTask DisposeAsyncCore()

public void Dispose()
{
// Use async disposal with ConfigureAwait(false) to avoid deadlocks
// and add a timeout to prevent indefinite blocking
// Use Task.Run to avoid deadlocks by running async disposal on thread pool
// Add timeout to prevent indefinite blocking
try
{
var disposeTask = DisposeAsync().ConfigureAwait(false);
disposeTask.GetAwaiter().GetResult();
var disposeTask = Task.Run(async () => await DisposeAsync().ConfigureAwait(false));
if (!disposeTask.Wait(TimeSpan.FromSeconds(30)))
{
// Log warning if disposal times out, but don't throw
// as per IDisposable pattern
}
}
catch
{
Expand Down