NullReferenceException - when using Akka.Net v1.5.12 and Akka.Streams.Amqp.RabbitMq v1.5.8

[marekkardos]

Version Information
Akka.Net v1.5.12
Akka.Hosting v1.5.12
Akka.Streams v1.5.12
Akka.Streams.Amqp.RabbitMq v1.5.8
Akka.Cluster.Hosting v1.5.12

Describe the bug
Both Producer and Consumer of the Sample are throwing NullReferenceException.

To Reproduce
Steps to reproduce the behavior:

1. Checkout master from
   https://github.com/petabridge/akkadotnet-code-samples/tree/master/src/reliability/rabbitmq-backpressure

2. Update NugetDependencies in the project: ReliableRabbitMQ.Shared

<PropertyGroup>
    <TargetFramework>$(NetRuntime)</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
</PropertyGroup>

<ItemGroup>
    <PackageReference Include="Akka" Version="1.5.12" />
    <PackageReference Include="Akka.Hosting" Version="1.5.12" />
    <PackageReference Include="Akka.Streams" Version="1.5.12" />
    <PackageReference Include="Akka.Streams.Amqp.RabbitMq" Version="1.5.8" />
    <PackageReference Include="Akka.Cluster.Hosting" Version="1.5.12" />
</ItemGroup>

3. Run both ReliableRabbitMQ.Consumer and ReliableRabbitMQ.Producer

4. See the error in console.

Expected behavior
Both ReliableRabbitMQ.Consumer and ReliableRabbitMQ.Producer are working without an error.

Actual behavior
Both ReliableRabbitMQ.Consumer and ReliableRabbitMQ.Producer console apps are throwing NullReferenceException.

-------------------------------- Producer --------------------------------
[ERROR][08. 07. 2023 12:36:44.268Z][Thread 0014][[akka://RabbitMQProducer/user/amqp-producer/StreamSupervisor-1/Flow-1-2-AmqpSink#881794866]] Error during PreStart in [AmqpSink]
Cause: RabbitMQ.Client.Exceptions.BrokerUnreachableException: None of the specified endpoints were reachable
---> System.AggregateException: One or more errors occurred. (Object reference not set to an instance of an object.)
---> System.NullReferenceException: Object reference not set to an instance of an object.
at RabbitMQ.Client.Impl.SocketFrameHandler..ctor(AmqpTcpEndpoint endpoint, Func2 socketFactory, TimeSpan connectionTimeout, TimeSpan readTimeout, TimeSpan writeTimeout) at RabbitMQ.Client.ConnectionFactory.CreateFrameHandler(AmqpTcpEndpoint endpoint) at RabbitMQ.Client.EndpointResolverExtensions.SelectOne[T](IEndpointResolver resolver, Func2 selector)
--- End of inner exception stack trace ---
at RabbitMQ.Client.EndpointResolverExtensions.SelectOne[T](IEndpointResolver resolver, Func2 selector) at RabbitMQ.Client.Framing.Impl.AutorecoveringConnection.Init(IEndpointResolver endpoints) at RabbitMQ.Client.ConnectionFactory.CreateConnection(IEndpointResolver endpointResolver, String clientProvidedName) --- End of inner exception stack trace --- at RabbitMQ.Client.ConnectionFactory.CreateConnection(IEndpointResolver endpointResolver, String clientProvidedName) at Akka.Streams.Amqp.RabbitMq.AmqpConnectorLogic.PreStart() --- End of stack trace from previous location --- at Akka.Actor.PipeToSupport.PipeTo(Task taskToPipe, ICanTell recipient, Boolean useConfigureAwait, IActorRef sender, Func1 success, Func`2 failure)
at Akka.Streams.Implementation.Fusing.GraphInterpreter.Init(IMaterializer subMaterializer)

-------------------------------- Consumer --------------------------------
[ERROR][08. 07. 2023 12:36:45.507Z][Thread 0014][[akka://RabbitConsumer/user/amqp-consumer/amqp-consumer/StreamSupervisor-1/Flow-0-0-unknown-operation#844566059]] Error during PreStart in [AmqpSource]
Cause: RabbitMQ.Client.Exceptions.BrokerUnreachableException: None of the specified endpoints were reachable
---> System.AggregateException: One or more errors occurred. (Object reference not set to an instance of an object.)
---> System.NullReferenceException: Object reference not set to an instance of an object.
at RabbitMQ.Client.Impl.SocketFrameHandler..ctor(AmqpTcpEndpoint endpoint, Func2 socketFactory, TimeSpan connectionTimeout, TimeSpan readTimeout, TimeSpan writeTimeout) at RabbitMQ.Client.ConnectionFactory.CreateFrameHandler(AmqpTcpEndpoint endpoint) at RabbitMQ.Client.EndpointResolverExtensions.SelectOne[T](IEndpointResolver resolver, Func2 selector)
--- End of inner exception stack trace ---
at RabbitMQ.Client.EndpointResolverExtensions.SelectOne[T](IEndpointResolver resolver, Func`2 selector)
at RabbitMQ.Client.Framing.Impl.AutorecoveringConnection.Init(IEndpointResolver endpoints)
at RabbitMQ.Client.ConnectionFactory.CreateConnection(IEndpointResolver endpointResolver, String clientProvidedName)
--- End of inner exception stack trace ---
at RabbitMQ.Client.ConnectionFactory.CreateConnection(IEndpointResolver endpointResolver, String clientProvidedName)
at Akka.Streams.Amqp.RabbitMq.AmqpConnectorLogic.PreStart()
at Akka.Streams.Implementation.Fusing.GraphInterpreter.Init(IMaterializer subMaterializer)

Screenshots

Environment
Windows 10 Pro 22H2,
RabbitMQ 3.11.10 on Erlang 25.3 running in Docker,
.NET 6

[marekkardos]

I've just realized the problem is caused by Akka.Streams.Amqp.RabbitMq v1.5.8,
As I downgraded to Akka.Streams.Amqp.RabbitMq v1.5.7 the problem disapeared.
Now it works fine with the older version.

[Aaronontheweb]

I've just realized the problem is caused by Akka.Streams.Amqp.RabbitMq v1.5.8, As I downgraded to Akka.Streams.Amqp.RabbitMq v1.5.7 the problem disapeared. Now it works fine with the older version.

Weird, not sure what could be causing that. I'll take a look at the diffs.

[Aaronontheweb]

Found the problem - this PR introduced a regression in v1.5.8 that can cause this NRE: #1612