Only QOS0 retained messages are received by the client upon subscription.

[jkompis]

Describe the bug

Retained messages published with other than QOS 0 aren't received by the client upon subscription.

Which component is your bug related to?

• Server

To Reproduce

See code example.

Expected behavior

Upon subscription client will received all retained messages not only ones with QOS 0.

Code example

using System.Text;
using MQTTnet;
using MQTTnet.Client;
using MQTTnet.Diagnostics;
using MQTTnet.Packets;
using MQTTnet.Protocol;


// prepare server
var logger = new MqttNetEventLogger();
logger.LogMessagePublished += (_, eventArgs) =>
{
    Console.WriteLine(eventArgs.LogMessage.Message);
};
var factory = new MqttFactory(logger);
var serverOptions = factory.CreateServerOptionsBuilder()
    .WithDefaultEndpoint()
    .Build();
var mqttServer = factory.CreateMqttServer(serverOptions);

await mqttServer.StartAsync();

var clientOptions = factory.CreateClientOptionsBuilder()
    .WithTcpServer("127.0.0.1", 1883)
    .WithCleanSession()
    .Build();


// publish retained message
var writeClient = factory.CreateMqttClient();

await writeClient.ConnectAsync(clientOptions);
await writeClient.PublishAsync(new MqttApplicationMessage
{
    Topic = "test_topic/0",
    Payload = Encoding.UTF8.GetBytes(@"{""hello"":0}"),
    Retain = true,
    QualityOfServiceLevel = MqttQualityOfServiceLevel.AtMostOnce
});
await writeClient.PublishAsync(new MqttApplicationMessage
{
    Topic = "test_topic/1",
    Payload = Encoding.UTF8.GetBytes(@"{""hello"":1}"),
    Retain = true,
    QualityOfServiceLevel = MqttQualityOfServiceLevel.AtLeastOnce
});
await writeClient.PublishAsync(new MqttApplicationMessage
{
    Topic = "test_topic/2",
    Payload = Encoding.UTF8.GetBytes(@"{""hello"":2}"),
    Retain = true,
    QualityOfServiceLevel = MqttQualityOfServiceLevel.ExactlyOnce
});
await writeClient.DisconnectAsync();


// create new client and subscribe
var readClient = factory.CreateMqttClient();

readClient.ApplicationMessageReceivedAsync += eventArgs =>
{
    Console.WriteLine($"message received {eventArgs.ApplicationMessage.Topic}");
    return Task.CompletedTask;
};

await readClient.ConnectAsync(clientOptions);
await readClient.SubscribeAsync(new MqttTopicFilter
{
    Topic = "test_topic/+",
    QualityOfServiceLevel = MqttQualityOfServiceLevel.ExactlyOnce
});


// give it some time 
await Task.Delay(5000);

await readClient.DisconnectAsync();
await mqttServer.StopAsync();

[chkr1011]

Please test with version 4.0.1.184 from the MyGet feed (see Readme). I fixed the issue in this version. If it works I will release a hotfix version soon.

[jkompis]

It works as expected with 4.0.1.184.

[jkompis]

Sorry not sure it it was supposed to be closed by me and now so I reopen it.