Cancellation token not canceled in AsyncEventingBasicConsumer.ReceivedAsync

[Andersso]

Describe the bug

Hi again! I’ve noticed that AsyncEventingBasicConsumer provides a CancellationToken in BasicDeliverEventArgs during the ReceivedAsync event. However, that token never actually gets cancelled. If I close the channel while awaiting inside ReceivedAsync, I’d expect the token to trigger so I can bail out gracefully. Instead, the token stays active, and CloseAsync ends up waiting forever for the task to complete.

Reproduction steps

using RabbitMQ.Client;
using RabbitMQ.Client.Events;

var factory = new ConnectionFactory
{
    HostName = "localhost",
    UserName = "guest",
    Password = "guest",
};

const string exchangeName = "TestExchange";
const string queueName = "TestQueue";

// Setup
await using var connection = await factory.CreateConnectionAsync();

var channel = await connection.CreateChannelAsync();
await channel.ExchangeDeclareAsync(exchangeName, ExchangeType.Topic);
await channel.QueueDeclareAsync(queueName, false, true, true);

await channel.QueueBindAsync(queueName, exchangeName, queueName);

var consumer = new AsyncEventingBasicConsumer(channel);
consumer.ReceivedAsync += async (_, args) =>
{
    // Wait until cancellation token is cancelled
    await Task.Delay(-1, args.CancellationToken);
};

await channel.BasicConsumeAsync(queueName, true, consumer);

// Publish
await channel.BasicPublishAsync(exchangeName, queueName, "Hello"u8.ToArray());

// Give some time for the message to be processed
await Task.Delay(100);

// Close
await channel.CloseAsync();
await connection.CloseAsync();

Console.WriteLine("All good!");

Expected behavior

The CancellationToken provided in BasicDeliverEventArgs is cancelled when the channel closes (or is aborted), allowing the awaiting task to end quickly.

Additional context

I poked around in the code and noticed a token is never actually passed to IAsyncBasicConsumer.HandleBasicDeliverAsync.

I tried creating a CancellationTokenSource in the Channel class that I cancel in CloseAsync, then using its token when calling HandleBasicDeliverAsync. That change made things work as expected.

If you want, I can make pull request containing this fix.

[lukebakken]

If you want, I can make pull request containing this fix.

Please do!